Ecological and health risks assessment and spatial distribution of residual heavy metals in the soil of an e-waste circular economy park in Tianjin, China

Spatial distribution and health risks assessment of heavy metals in e-waste dumping sites from Pakistan

The present study focused on to determine the concentration and health risk of heavy metals (Cu, Pb, Zn, Cd, Hg, Cr) in e-waste contaminated soils collected from different provinces of Pakistan. Further, the impact of heavy metals on soil enzyme activities and microbial community was also investigated. The concentration (mg/kg) of Hg, Zn, Fe, Cu, Pb, Cd, and Cr ranged between 0-0.258, 2.284-6.587, 3.005-40.72, 8.67-36.88, 12.05-35.03, 1.03-2.43, and 33.13-60.05, respectively. The results revealed that Lahore site of Punjab province indicated more concentration of heavy metals as compared to other sites. The level of Cr at all sites whereas Hg at only two sites exceeds the World Health Organization standards (WHO) for soil. Soil enzyme activity exhibited dynamic trend among the sites. Maximum enzyme activity was observed for urease followed by phosphatase and catalase. Contamination factor (Cf), Pollution load index (PLI), and geo-accumulation index (Igeo) results showed that all the sites are highly contaminated with Cu, Cd, and Pb. Hazard index (HI) was less than 1 for children and adults suggesting non-carcinogenic health risk. Principle component analysis results depicted relation among Cr, Fr, catalase, and actinomycetes; Cd, OM, urease, and bacteria, and Pb, Cu, Zn, Hg, and phosphatase, suggesting soil enzymes and microbial community profiles were influenced by e-waste pollution. Therefore, there is a dire need to introduce sustainable e-waste recycling techniques as well as to make stringent e-waste management policies to reduce further environmental contamination.

Industrial hemp (Cannabis sativa L.) can utilize and remediate soil strongly contaminated with Cu, As, Cd, and Pb by phytoattenuation

Industrial hemp (Cannabis sativa L.) has great application potential in heavy metal-polluted soils owing to its safe non-food utilization. However, the fate of heavy metals in different varieties of hemp planted in strongly contaminated natural soils remains unknown. Here, we investigated the growth, heavy metal uptake, distribution, and transfer of nine hemp varieties in soils strongly contaminated with Cu, As, Cd, and Pb. Hemp variety and metal type were the main factors affecting the growth and heavy metal uptake in hemp. The nine hemp varieties grew well in the contaminated soils; however, differences existed among the varieties. The biomass of Z3 reached 5669.1 kg hm-1, whereas that of Yunma No. 1 was only 51.8 % of Z3. The plant height, stalk diameter, and stalk bark thickness of Z3 were greater than those of the other varieties, reaching 168 cm, 9.2 mm, and 0.56 mm, respectively. Permanova's analysis revealed that the total effects of Cu, As, Cd, and Pb on the growth of the nine hemp varieties reached 60 %, with leaf As having the greatest effect, reaching 16 %. , Even in strongly contaminated soils, the nine varieties showed poor Cu, As, Cd, and Pb uptake. Most of the Cu, As, Cd, and Pb were retained in the root, reaching 57.7-72.4, 47.6-64.7, 76.0-92.9, and 70.0-87.8 %, respectively. Overall, the Cu, As, Cd, and Pb uptake of Wanma No.1 was the highest among the nine varieties, whereas that of Guangxi Bama was the lowest. These results indicate that hemp is a viable alternative for phytoattenuation in soils contaminated with heavy metals because of its ability to tolerate and accumulate Cu, As, Cd, and Pb in its roots, and Guangxi Bama is superior to the other varieties considering the safe utilization of hemp products.

Integrated assessment of potentially toxic elements in soil of the Kangdian metallogenic province: A two-point machine learning approach

The accumulation of potentially toxic elements in soil poses significant risks to ecosystems and human well-being due to their inherent toxicity, widespread presence, and persistence. The Kangdian metallogenic province, famous for its iron-copper deposits, faces soil pollution challenges due to various potentially toxic elements. This study explored a comprehensive approach that combinescombines the spatial prediction by the two-point machine learning method and ecological-health risk assessment to quantitatively assess the comprehensive potential ecological risk index (PERI), the total hazard index (THI) and the total carcinogenic risk (TCR). The proportions of copper (Cu), cadmium (Cd), manganese (Mn), lead (Pb), zinc (Zn), and arsenic (As) concentrations exceeding the risk screening values (RSVs) were 15.03%, 5.1%, 3.72%, 1.24%, 1.1%, and 0.13%, respectively, across the 725 collected samples. Spatial prediction revealed elevated levels of As, Cd, Cu, Pb, Zn, mercury (Hg), and Mn near the mining sites. Potentially toxic elements exert a slight impact on soil, some regions exhibit moderate to significant ecological risk, particularly in the southwest. Children face higher non-carcinogenic and carcinogenic health risks compared to adults. Mercury poses the highest ecological risk, while chromium (Cr) poses the greatest health hazard for all populations. Oral ingestion represents the highest non-oncogenic and oncogenic risks in all age groups. Adults faced acceptable non-carcinogenic risks. Children in the southwest region confront higher health risks, both non-carcinogenic and carcinogenic, from mining activities. Urgent measures are vital to mitigate Hg and Cr contamination while promoting handwashing practices is essential to minimize health risks.

Source-sink response analysis of heavy metals and soil pollution assessment in non-ferrous metal industrial agglomeration areas based on decision unit

Soil heavy metals (HMs) pollution is a worldwide concern. In this study, decision units based on "source-sink relationship" were established using multi-source data. The source-sink response of heavy metals in agricultural soils at the regional scale was analyzed using machine learning methods, receptor models, and geospatial analysis. The comprehensive pollution risk score (CRS) was proposed by integrating a variety of key evaluation indicators to evaluate the pollution degree of each decision unit. We divided the study area into 193 decision units, the proportions of sites with concentrations of Cd, Hg, As, Pb, and Cr exceeding the most stringent risk screening values were 16.4 %, 2.2 %, 4.0 %, 7.6 %, and 0.2 %, respectively. Agricultural activities (livestock manure, fertilizer, sewage irrigation), industrial activities (rare earth ore and tungsten‑molybdenum mining and smelting), and soil parent material are the dominant pollution sources of HMs in the study area. The risk of contamination of each element is ranked from largest to smallest according to the CRS as Cd > Hg > Pb > As > Cr. The western and southwestern water pollution decision units are the areas with the highest risk of soil HMs contamination. This quantitative evaluation framework can provide a relatively accurate decision basis for soil pollution management.

A review of heavy metal risks around e-waste sites and comparable municipal dumpsites in major African cities: Recommendations and future perspectives

In Africa, the effects of informal e-waste recycling on the environment are escalating. It is regularly transported from developed to developing nations, where it is disassembled informally in search of precious metals, thus increasing human exposure to harmful compounds. Africa has a serious problem with e-waste, as there are significant facilities in Ghana and Nigeria where imported e-waste is unsafely dismantled. however, because they are in high demand and less expensive than new ones, old electronic and electrical items are imported in large quantities, just like in many developing nations. After that, these objects are frequently scavenged to recover important metals through heating, burning, incubation in acids, and other techniques. Serious health hazards are associated with these activities for workers and individuals close to recycling plants. At e-waste sites in Africa, there have been documented instances of elevated concentrations of hazardous elements, persistent organic pollutants, and heavy metals in dust, soils, and vegetation, including plants consumed as food. Individuals who handle and dispose of e-waste are exposed to highly hazardous chemical substances. This paper examines heavy metal risks around e-waste sites and comparable municipal dumpsites in major African cities. Elevated concentrations of these heavy metals metal in downstream aquatic and marine habitats have resulted in additional environmental impacts. These effects have been associated with unfavourable outcomes in marine ecosystems, such as reduced fish stocks characterized by smaller sizes, increased susceptibility to illness, and decreased population densities. The evidence from the examined studies shows how much e-waste affects human health and the environment in Africa. Sub-Saharan African nations require a regulatory framework that includes specialized laws, facilities, and procedures for the safe recycling and disposal of e-waste.

A comparative study on metal pollution from surface dust of informal and formal e-waste recycling sectors in national capital region of New Delhi and associated risk assessment

Electrical and electronic waste (e-waste) is considered as resource and secondary source of metals, and is being recycled for recovery of precious and base metals. But the processes of recycling and the waste generated during e-waste recycling in informal and formal sectors contribute toxic metals in to the environment. This work aimed to compare the environmental and health impacts of informal and formal e-waste recycling facilities at New Delhi and Bhiwadi Industrial area in India, respectively. Here, concentrations of Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sn, V, Zn, and Ag, and As in surface dust collected from informal and formal recycling sectors and their associated pollution, human health and ecological risk are presented. Metal concentrations were higher than the background levels in both sectors. Contamination factor (Cf), contamination degree (Cdeg), pollution load index (PLI), geo-accumulation index (Igeo) and enrichment factor (EnF) of metals indicated severe pollution levels in both sectors. However, contamination in informal sector was comparatively higher than the formal sector. Sampling sites in both sectors had very high ecological risk. Storage, dismantling/shredding and recycling techniques were contributors of metals in surface dust in formal sector whereas fumes deposition, re-suspension, and dried by-products during acid bath treatments were additional sources in informal sector. Metal pollution depends on metal(s), e-waste type(s) and recycling sector(s). Total non-carcinogenic health risk due to metals was 6.5E+00 and 6.0E+01 and 6.2E+00 and 5.5E+01 in adult and children in informal and formal sectors, respectively. Total carcinogenic risk was 3.3E-03 and 7.2E-03 in informal and formal sectors, respectively. Ingestion was major pathways of metals followed by dermal and inhalation and children were more prone to risk compared to adults. Formal sectors too cause metal pollution but to lesser degree compared to informal. More effective pollution control measures are required in formal sector to control environmental pollution.

Distribution of microplastics in shoreline water and sediment of the Ganges River Basin to Meghna Estuary in Bangladesh

This study focused on the distribution of microplastics in the water and sediment of the Ganges River Basin to the Meghna Estuary in Bangladesh. Thirty points were sampled from Chapainawabganj district (India-Bangladesh border) to Chandpur district (Meghna Estuary). The morphological appearances were recognized by stereomicroscope and SEM-EDX analysis. Potential ecological risks were also measured. The average microplastic concentration in upstream and downstream water was 50.9 ± 24.4 particles/L and 64.1 ± 26.3 particles/L, respectively, and the sediment concentration was 2953.49 ± 1670.52 particles/kg in upstream sediment and 4014.66 ± 1717.59 particles/kg in downstream sediment. In upstream water, the most dominant morphological appearance was fragment shape, blue colour and 1-2 mm in size. The appearance of downstream water was fragments shape, red colour and 0.1-0.5 mm in size. In upstream sediment, the most dominant morphological appearance was fragment shape, red colour and < 0.1 mm in size. The appearance of downstream sediment was fibre shape, red colour and < 0.1 mm in size. Seven polymer types were discovered in water, dominated by low-density polyethylene (LDPE), and eight polymer types in sediment, dominated by polyamide (PA). The correlation between the size and shape of particles was analyzed using principal component analysis. The overall pollution load index of the Ganges River Basin to the Meghna Estuary was 1.86, higher than the other studies done in Bangladesh. Surprisingly, the nemerow pollution index (NPI), contamination factor (CF), pollution load index (PLI), polymer hazard index (PHI), and potential ecological risk (Ei)- all five ecological risk indicators had low to very high water and sediment pollution in the Ganges River Basin due to microplastic exposure. The data produced through this study will drive increasing awareness regarding microplastic pollution in the vast river ecosystem. Given the widespread presence of this pollution, it highlights the necessity for continuous national monitoring of microplastics.

Soil heavy metal pollution from waste electrical and electronic equipment of repair and junk shops in southern Thailand and their ecological risk

The waste electrical and electronic equipment (WEEE) stream in Thailand shifted from exporting WEEE to recycling them in domestic enterprises after China's import restrictions on e-waste in 2018. This study aims to investigate the pollution status, pollution sources, and ecological risk of heavy metals from manual WEEE dismantling facilities (12 repair shops and 8 junk shops) in the Nakhon Si Thammarat province of southern Thailand by examining the concentrations of As, Cd, Ni, and Pb in the topsoil (0-15 cm) during the wet and dry seasons. The results revealed that the mean concentrations of all heavy metals were higher during the dry season than in the wet season. The concentrations of analyzed soil heavy metals decreased as the intensity of e-waste dismantling activities increased, with recycling sites > repair sites > control sites (no e-waste recycling activities). Only 10% of WEEE processing workshops (junk shops) had soil Pb and As concentrations that exceeded Thailand's residential soil quality standards. However, ecological indexing models based on the geo-accumulation index found that 75% of electric repair shops were contaminated with the analyzed heavy metals, particularly Pb. Moreover, the Nemerow integrated pollution index indicated that 16.7% of electric repair shops were on the pollution warning line. Our findings suggest that policymakers should promote ecological risk assessment as a method for mitigating the negative environmental impact of electronic repair businesses, which are widely dispersed in residential areas and tend to dominate the WEEE stream because of the circular economy concept of "right to repair", and highlight the decline of junk shops and e-waste dismantling villages for waste export resulting from China's ban.

Effects of long-term zinc smelting activities on the distribution and health risk of heavy metals in agricultural soils of Guizhou province, China

To assess the effect of zinc smelting on environment and human health, the concentration, distribution, sources and health risk of eight heavy metals (Pb, Cd, Cu, Zn, Cr, Ni, Mn, and As) were investigated from agricultural soils in a long-term Zn smelting area in Guizhou, China. Different health risk assessment methods and models were used to access health risks. The results show that the concentrations of all the eight heavy metals were significantly higher than their corresponding background values (p < 0.05). Pb, Cd, and As were the most contaminated elements, with 93.6%, 90.3% and 48.4% of agricultural soil samples higher than the risk screening values, respectively. Statistical analysis indicated that Pb, Cd, Cu, Zn, Mn, and As could be mainly accounted for Zn smelting activities, while Cr and Ni may be generally more controlled by natural sources. The geo-accumulation index (Igeo) suggested that the most seriously contaminating heavy metals were Pb, Cd, and Zn, with 96.8%, 90.3%, and 96.8%, respectively, of the soil samples classified as moderately to extremely contaminated. The non-carcinogenic health risk associated with Pb, Cd and As were observed for children, meanwhile, the carcinogenic risk due to As was found for both adults and children. Regardless of cancer risk or non-cancer risk, local children are at greater risk than adults. Therefore, Pb, Cd and As play the leading role to cause potential health risks in the study area, which need to be paid more attention and also effective control measures should be taken.

Pollution threshold assessment and risk area delineation of heavy metals in soils through the finite mixture distribution model and Bayesian maximum entropy theory

Pollution threshold and high-risk area determination for heavy metals is important for effectively developing pollution control strategies. Based on heavy metal contents in 3627 dense samples, an integrated framework combining the finite mixture distribution model and Bayesian maximum entropy (BME) theory was proposed to assess pollution thresholds, contamination levels and risk areas in an uncertain environment for soil heavy metals. The results showed that the average heavy metal contents were in the order Zn > Cr > Pb > Cu > Ni > As > Cd > Hg, with strong/moderate variation, and the corresponding pollution thresholds were 158.39, 84.29, 47.84, 49.75, 28.95, 18.01, 0.49 and 0.16 mg/kg, respectively. The thresholds were consistently greater than the Zhejiang Province backgrounds but lower than the national risk screening values, except for Cd. Approximately 27.9% of the samples were classified as contaminated at various levels, and they were distributed in the northern, northwestern and eastern regions of the study area. Additionally, 3.73%, 5.34% and 8.22% of the total area were classified as at-risk areas under confidence levels of 95%, 90% and 75%, respectively, through BME theory. The findings provide a reasonable classification system and suggestions for heavy metal pollution management and control.

Geochemical distribution and environmental risk assessment of trace metals in groundwater released from e-waste management activities in Lahore, Pakistan

Non-sustainable e-waste recycling and dumping activities release trace metals into the ambient environment where they may threaten the biological communities and human health. A total of 45 groundwater and 21 leachate samples were collected from seven recycling, seven dumping, and one reference site in Lahore, Pakistan, and analyzed for Cu, Pb, Zn, Cd, Mn, and Fe in atomic absorption spectrophotometer. Comparing the results with the World Health Organization (WHO) standards of drinking water, only the concentrations of Cu, Zn, Mn, and Fe at all sites were found to be within the permissible limits, i.e., 2, 3, 0.5, and 1 mg/L, respectively. In leachates, only Cd and Mn at one site (0.204 and 8.636 mg/L, respectively) exceeded the allowable limits of National Environmental Quality Standards of Municipal and Liquid industrial effluents. Geo-accumulation index, contamination factor, contamination degree, and pollution load index values showed no to moderate contamination. The ecological risk index did not exceed 150, depicting low risk to nearby biological communities. The non-carcinogenic health risk assessment showed a hazard index value greater than 1 at all sites for children (2.04) and adults (1.52), with Pb being the major contributor to adverse health impacts via ingestion and dermal route. Children (1.21 × 10^-4) were at a more significant threat of carcinogenic risk from Pb and Cd as compared to adults (8.10 × 10^-5). Therefore, there is a dire need to introduce sustainable e-waste recycling and managing techniques to reduce further groundwater contamination via the percolation of trace metals and to reduce the current contamination level.

Waste of electrical and electronic equipment management from the perspective of a circular economy: A Review

In addition to the difficulties involved in the management of conventional solid waste, the management of waste of electrical and electronic equipment (WEEE) is significantly more complex due to its unusual chemical composition and fast generation. Both developed and developing countries have been looking for solutions to deal with the problems caused by the growing flow of WEEE, especially regarding sustainable solutions based on reducing resource exploitation by the recovery of materials from this type of waste. In this context, this work presents a quali-quantitative and comprehensive literature review of the publications on the management of WEEE, from the perspective of a circular economy. The results showed that the first publications on the topic appear in 2006, with a significant increase from 2015, the year when the Circular Economy Action Plan was instituted in the European Community. The most prominent authors have been giving emphasis to researches on recycling, reuse and technologies for the recovery of materials/energy from WEEE. Nevertheless, few studies have been found focusing on the prevention/reduction in WEEE generation, priority actions of the WEEE management hierarchy. The works analysed show that the current management of WEEE, despite considering the circularity of materials, prioritizes the development of technological solutions of the end-of-pipe type, greatly represented by the recovery of materials, instead of preventing the generation, which may be detrimental to long-term sustainability. The work ends with the presentation of a SWOT-TOWS (strengths, weaknesses, opportunities and threats) analysis conducted to define the main strategies for the improvement of WEEE management from a circular economy perspective.

The Minderoo-Monaco Commission on Plastics and Human Health

Background

Plastics have conveyed great benefits to humanity and made possible some of the most significant advances of modern civilization in fields as diverse as medicine, electronics, aerospace, construction, food packaging, and sports. It is now clear, however, that plastics are also responsible for significant harms to human health, the economy, and the earth's environment. These harms occur at every stage of the plastic life cycle, from extraction of the coal, oil, and gas that are its main feedstocks through to ultimate disposal into the environment. The extent of these harms not been systematically assessed, their magnitude not fully quantified, and their economic costs not comprehensively counted.

Goals

The goals of this Minderoo-Monaco Commission on Plastics and Human Health are to comprehensively examine plastics' impacts across their life cycle on: (1) human health and well-being; (2) the global environment, especially the ocean; (3) the economy; and (4) vulnerable populations-the poor, minorities, and the world's children. On the basis of this examination, the Commission offers science-based recommendations designed to support development of a Global Plastics Treaty, protect human health, and save lives.

Report Structure

This Commission report contains seven Sections. Following an Introduction, Section 2 presents a narrative review of the processes involved in plastic production, use, and disposal and notes the hazards to human health and the environment associated with each of these stages. Section 3 describes plastics' impacts on the ocean and notes the potential for plastic in the ocean to enter the marine food web and result in human exposure. Section 4 details plastics' impacts on human health. Section 5 presents a first-order estimate of plastics' health-related economic costs. Section 6 examines the intersection between plastic, social inequity, and environmental injustice. Section 7 presents the Commission's findings and recommendations.

Plastics

Plastics are complex, highly heterogeneous, synthetic chemical materials. Over 98% of plastics are produced from fossil carbon- coal, oil and gas. Plastics are comprised of a carbon-based polymer backbone and thousands of additional chemicals that are incorporated into polymers to convey specific properties such as color, flexibility, stability, water repellence, flame retardation, and ultraviolet resistance. Many of these added chemicals are highly toxic. They include carcinogens, neurotoxicants and endocrine disruptors such as phthalates, bisphenols, per- and poly-fluoroalkyl substances (PFAS), brominated flame retardants, and organophosphate flame retardants. They are integral components of plastic and are responsible for many of plastics' harms to human health and the environment.Global plastic production has increased almost exponentially since World War II, and in this time more than 8,300 megatons (Mt) of plastic have been manufactured. Annual production volume has grown from under 2 Mt in 1950 to 460 Mt in 2019, a 230-fold increase, and is on track to triple by 2060. More than half of all plastic ever made has been produced since 2002. Single-use plastics account for 35-40% of current plastic production and represent the most rapidly growing segment of plastic manufacture.Explosive recent growth in plastics production reflects a deliberate pivot by the integrated multinational fossil-carbon corporations that produce coal, oil and gas and that also manufacture plastics. These corporations are reducing their production of fossil fuels and increasing plastics manufacture. The two principal factors responsible for this pivot are decreasing global demand for carbon-based fuels due to increases in 'green' energy, and massive expansion of oil and gas production due to fracking.Plastic manufacture is energy-intensive and contributes significantly to climate change. At present, plastic production is responsible for an estimated 3.7% of global greenhouse gas emissions, more than the contribution of Brazil. This fraction is projected to increase to 4.5% by 2060 if current trends continue unchecked.

Plastic Life Cycle

The plastic life cycle has three phases: production, use, and disposal. In production, carbon feedstocks-coal, gas, and oil-are transformed through energy-intensive, catalytic processes into a vast array of products. Plastic use occurs in every aspect of modern life and results in widespread human exposure to the chemicals contained in plastic. Single-use plastics constitute the largest portion of current use, followed by synthetic fibers and construction.Plastic disposal is highly inefficient, with recovery and recycling rates below 10% globally. The result is that an estimated 22 Mt of plastic waste enters the environment each year, much of it single-use plastic and are added to the more than 6 gigatons of plastic waste that have accumulated since 1950. Strategies for disposal of plastic waste include controlled and uncontrolled landfilling, open burning, thermal conversion, and export. Vast quantities of plastic waste are exported each year from high-income to low-income countries, where it accumulates in landfills, pollutes air and water, degrades vital ecosystems, befouls beaches and estuaries, and harms human health-environmental injustice on a global scale. Plastic-laden e-waste is particularly problematic.

Environmental Findings

Plastics and plastic-associated chemicals are responsible for widespread pollution. They contaminate aquatic (marine and freshwater), terrestrial, and atmospheric environments globally. The ocean is the ultimate destination for much plastic, and plastics are found throughout the ocean, including coastal regions, the sea surface, the deep sea, and polar sea ice. Many plastics appear to resist breakdown in the ocean and could persist in the global environment for decades. Macro- and micro-plastic particles have been identified in hundreds of marine species in all major taxa, including species consumed by humans. Trophic transfer of microplastic particles and the chemicals within them has been demonstrated. Although microplastic particles themselves (>10 µm) appear not to undergo biomagnification, hydrophobic plastic-associated chemicals bioaccumulate in marine animals and biomagnify in marine food webs. The amounts and fates of smaller microplastic and nanoplastic particles (MNPs <10 µm) in aquatic environments are poorly understood, but the potential for harm is worrying given their mobility in biological systems. Adverse environmental impacts of plastic pollution occur at multiple levels from molecular and biochemical to population and ecosystem. MNP contamination of seafood results in direct, though not well quantified, human exposure to plastics and plastic-associated chemicals. Marine plastic pollution endangers the ocean ecosystems upon which all humanity depends for food, oxygen, livelihood, and well-being.

Human Health Findings

Coal miners, oil workers and gas field workers who extract fossil carbon feedstocks for plastic production suffer increased mortality from traumatic injury, coal workers' pneumoconiosis, silicosis, cardiovascular disease, chronic obstructive pulmonary disease, and lung cancer. Plastic production workers are at increased risk of leukemia, lymphoma, hepatic angiosarcoma, brain cancer, breast cancer, mesothelioma, neurotoxic injury, and decreased fertility. Workers producing plastic textiles die of bladder cancer, lung cancer, mesothelioma, and interstitial lung disease at increased rates. Plastic recycling workers have increased rates of cardiovascular disease, toxic metal poisoning, neuropathy, and lung cancer. Residents of "fenceline" communities adjacent to plastic production and waste disposal sites experience increased risks of premature birth, low birth weight, asthma, childhood leukemia, cardiovascular disease, chronic obstructive pulmonary disease, and lung cancer.During use and also in disposal, plastics release toxic chemicals including additives and residual monomers into the environment and into people. National biomonitoring surveys in the USA document population-wide exposures to these chemicals. Plastic additives disrupt endocrine function and increase risk for premature births, neurodevelopmental disorders, male reproductive birth defects, infertility, obesity, cardiovascular disease, renal disease, and cancers. Chemical-laden MNPs formed through the environmental degradation of plastic waste can enter living organisms, including humans. Emerging, albeit still incomplete evidence indicates that MNPs may cause toxicity due to their physical and toxicological effects as well as by acting as vectors that transport toxic chemicals and bacterial pathogens into tissues and cells.Infants in the womb and young children are two populations at particularly high risk of plastic-related health effects. Because of the exquisite sensitivity of early development to hazardous chemicals and children's unique patterns of exposure, plastic-associated exposures are linked to increased risks of prematurity, stillbirth, low birth weight, birth defects of the reproductive organs, neurodevelopmental impairment, impaired lung growth, and childhood cancer. Early-life exposures to plastic-associated chemicals also increase the risk of multiple non-communicable diseases later in life.

Economic Findings

Plastic's harms to human health result in significant economic costs. We estimate that in 2015 the health-related costs of plastic production exceeded $250 billion (2015 Int$) globally, and that in the USA alone the health costs of disease and disability caused by the plastic-associated chemicals PBDE, BPA and DEHP exceeded $920 billion (2015 Int$). Plastic production results in greenhouse gas (GHG) emissions equivalent to 1.96 gigatons of carbon dioxide (CO2e) annually. Using the US Environmental Protection Agency's (EPA) social cost of carbon metric, we estimate the annual costs of these GHG emissions to be $341 billion (2015 Int$).These costs, large as they are, almost certainly underestimate the full economic losses resulting from plastics' negative impacts on human health and the global environment. All of plastics' economic costs-and also its social costs-are externalized by the petrochemical and plastic manufacturing industry and are borne by citizens, taxpayers, and governments in countries around the world without compensation.

Social Justice Findings

The adverse effects of plastics and plastic pollution on human health, the economy and the environment are not evenly distributed. They disproportionately affect poor, disempowered, and marginalized populations such as workers, racial and ethnic minorities, "fenceline" communities, Indigenous groups, women, and children, all of whom had little to do with creating the current plastics crisis and lack the political influence or the resources to address it. Plastics' harmful impacts across its life cycle are most keenly felt in the Global South, in small island states, and in disenfranchised areas in the Global North. Social and environmental justice (SEJ) principles require reversal of these inequitable burdens to ensure that no group bears a disproportionate share of plastics' negative impacts and that those who benefit economically from plastic bear their fair share of its currently externalized costs.

Conclusions

It is now clear that current patterns of plastic production, use, and disposal are not sustainable and are responsible for significant harms to human health, the environment, and the economy as well as for deep societal injustices.The main driver of these worsening harms is an almost exponential and still accelerating increase in global plastic production. Plastics' harms are further magnified by low rates of recovery and recycling and by the long persistence of plastic waste in the environment.The thousands of chemicals in plastics-monomers, additives, processing agents, and non-intentionally added substances-include amongst their number known human carcinogens, endocrine disruptors, neurotoxicants, and persistent organic pollutants. These chemicals are responsible for many of plastics' known harms to human and planetary health. The chemicals leach out of plastics, enter the environment, cause pollution, and result in human exposure and disease. All efforts to reduce plastics' hazards must address the hazards of plastic-associated chemicals.

Recommendations

To protect human and planetary health, especially the health of vulnerable and at-risk populations, and put the world on track to end plastic pollution by 2040, this Commission supports urgent adoption by the world's nations of a strong and comprehensive Global Plastics Treaty in accord with the mandate set forth in the March 2022 resolution of the United Nations Environment Assembly (UNEA).International measures such as a Global Plastics Treaty are needed to curb plastic production and pollution, because the harms to human health and the environment caused by plastics, plastic-associated chemicals and plastic waste transcend national boundaries, are planetary in their scale, and have disproportionate impacts on the health and well-being of people in the world's poorest nations. Effective implementation of the Global Plastics Treaty will require that international action be coordinated and complemented by interventions at the national, regional, and local levels.This Commission urges that a cap on global plastic production with targets, timetables, and national contributions be a central provision of the Global Plastics Treaty. We recommend inclusion of the following additional provisions:The Treaty needs to extend beyond microplastics and marine litter to include all of the many thousands of chemicals incorporated into plastics.The Treaty needs to include a provision banning or severely restricting manufacture and use of unnecessary, avoidable, and problematic plastic items, especially single-use items such as manufactured plastic microbeads.The Treaty needs to include requirements on extended producer responsibility (EPR) that make fossil carbon producers, plastic producers, and the manufacturers of plastic products legally and financially responsible for the safety and end-of-life management of all the materials they produce and sell.The Treaty needs to mandate reductions in the chemical complexity of plastic products; health-protective standards for plastics and plastic additives; a requirement for use of sustainable non-toxic materials; full disclosure of all components; and traceability of components. International cooperation will be essential to implementing and enforcing these standards.The Treaty needs to include SEJ remedies at each stage of the plastic life cycle designed to fill gaps in community knowledge and advance both distributional and procedural equity.This Commission encourages inclusion in the Global Plastic Treaty of a provision calling for exploration of listing at least some plastic polymers as persistent organic pollutants (POPs) under the Stockholm Convention.This Commission encourages a strong interface between the Global Plastics Treaty and the Basel and London Conventions to enhance management of hazardous plastic waste and slow current massive exports of plastic waste into the world's least-developed countries.This Commission recommends the creation of a Permanent Science Policy Advisory Body to guide the Treaty's implementation. The main priorities of this Body would be to guide Member States and other stakeholders in evaluating which solutions are most effective in reducing plastic consumption, enhancing plastic waste recovery and recycling, and curbing the generation of plastic waste. This Body could also assess trade-offs among these solutions and evaluate safer alternatives to current plastics. It could monitor the transnational export of plastic waste. It could coordinate robust oceanic-, land-, and air-based MNP monitoring programs.This Commission recommends urgent investment by national governments in research into solutions to the global plastic crisis. This research will need to determine which solutions are most effective and cost-effective in the context of particular countries and assess the risks and benefits of proposed solutions. Oceanographic and environmental research is needed to better measure concentrations and impacts of plastics <10 µm and understand their distribution and fate in the global environment. Biomedical research is needed to elucidate the human health impacts of plastics, especially MNPs.

Summary

This Commission finds that plastics are both a boon to humanity and a stealth threat to human and planetary health. Plastics convey enormous benefits, but current linear patterns of plastic production, use, and disposal that pay little attention to sustainable design or safe materials and a near absence of recovery, reuse, and recycling are responsible for grave harms to health, widespread environmental damage, great economic costs, and deep societal injustices. These harms are rapidly worsening.While there remain gaps in knowledge about plastics' harms and uncertainties about their full magnitude, the evidence available today demonstrates unequivocally that these impacts are great and that they will increase in severity in the absence of urgent and effective intervention at global scale. Manufacture and use of essential plastics may continue. However, reckless increases in plastic production, and especially increases in the manufacture of an ever-increasing array of unnecessary single-use plastic products, need to be curbed.Global intervention against the plastic crisis is needed now because the costs of failure to act will be immense.

Contamination Assessment and Potential Human Health Risks of Heavy Metals in Urban Soils from Grand Forks, North Dakota, USA

Heavy metal (HM) pollution of soil is an increasingly serious problem worldwide. The current study assessed the metal levels and ecological and human health risk associated with HMs in Grand Forks urban soils. A total 40 composite surface soil samples were investigated for Mn, Fe, Co, Ni, Cu, Zn, As, Pb, Hg, Cr, Cd and Tl using microwave-assisted HNO3-HCl acid digestion and inductively coupled plasma mass spectrometry (ICP-MS) analysis. The enrichment factor (EF), contamination factor (CF), geoaccumulation index (Igeo), ecological risk and potential ecological risk index were used for ecological risk assessment. The park soils revealed the following decreasing trend for metal levels: Fe > Mn > Zn > Cr > Ni > Cu > Pb > As > Co > Cd > Tl > Hg. Based on mean levels, all the studied HMs except As and Cr were lower than guideline limits set by international agencies. Principal component analysis (PCA) indicated that Mn, Fe, Co, Ni, Cu, Zn, As, Cd, Pb, Cr and Tl may originate from natural sources, while Hg, Pb, As and Cd may come from anthropogenic/mixed sources. The Igeo results showed that the soil was moderately polluted by As and Cd and, based on EF results, As and Cd exhibited significant enrichment. The contamination factor analysis revealed that Zn and Pb showed moderate contamination, Hg exhibited low to moderate contamination and As and Cd showed high contamination in the soil. Comparatively higher risk was noted for children over adults and, overall, As was the major contributor (>50%), followed by Cr (>13%), in the non-carcinogenic risk assessment. Carcinogenic risk assessment revealed that As and Cr pose significant risks to the populations associated with this urban soil. Lastly, this study showed that the soil was moderately contaminated by As, Cd, Pb and Hg and should be regularly monitored for metal contamination.

Informer-Based Safety Risk Prediction of Heavy Metals in Rice in China

Focused supervision and early warning of heavy metal (HM)-contaminated rice areas can effectively protect people's livelihood security and maintain social stability. To improve the accuracy of risk prediction, an Informer-based safety risk prediction model for HMs in rice is constructed in this paper. First, based on the national sampling data and residential consumption statistics of rice, we construct a dataset of evaluation indicators that can characterize the level of rice safety risk so as to form a safety risk space. Second, based on the K-medoids clustering algorithm, we classify the rice safety risk space into levels. Finally, we use the Informer neural network model to predict the safety risk indicators of rice in each province so as to predict the safety risk level. This study compares the prediction accuracy of a self-constructed dataset of rice safety risk assessment indicators. The experimental results show that the prediction precision of the method proposed in this paper reaches 99.17%, 91.77%, and 91.33% for low, medium, and high risk levels, respectively. The model provides technical support and a scientific basis for screening the time and area of HM contamination of rice, which needs focus.

Mapping soil arsenic pollution at a brownfield site using satellite hyperspectral imagery and machine learning

Heavy metal contamination is ubiquitous in brownfields. Traditional site investigation employs geostatistical interpolation methods (GIMs) to predict the distribution of soil pollutants after soil sampling and chemical analysis. However, the heterogeneity of soil pollution in brownfields makes the assumptions of GIMs no longer valid and further undermines the accuracy of soil investigation. In the present study, a satellite hyperspectral image processing and machine learning method was developed to map arsenic pollution at a brownfield site. To eliminate the noise caused by atmospheric factors and increase the efficiency of spectral data, 1.3 million spectral indexes (SIs) were constructed and 1171 of them were selected due to their high correlations with soil arsenic. Five machine learning methods, i.e., Random forest (RF), ExtraTrees, Adaptive Boosting, Extreme Gradient Trees, and Gradient Descent Boosting Trees (GDB) were built to predict soil arsenic. The RF method was found to render the best performance (r = 0.78), reducing 30 % of prediction errors compared with traditional GIMs. RF also maintained a relatively higher level of accuracy (r = 0.56) when the sampling grids increased to 100 m, which was higher than that of GIMs under a 50 m sampling grid (r = 0.42), revealing that the proposed method can provide more accurate results with fewer sampling points, namely less investigation cost. It was indicated that the second derivate was the most efficient preprocessing method to remove spectral noise and normalized difference (ND) was the most reliable spectral index construction strategy. Based on uncertainty analysis, the heterogeneity of soil arsenic distribution was considered the most influential factor causing prediction errors. This study demonstrates that machine learning based on satellite visible and near-infrared reflectance spectroscopy (VNIR) is a promising approach to map soil arsenic contamination at brownfield sites with high accuracy and low cost.

Irrigation suitability, health risk assessment and source apportionment of heavy metals in surface water used for irrigation near marble industry in Malakand, Pakistan

Water is a vital, finite resource whose quantity and quality are deteriorating as the world population increases. The current study aims to investigate the concentration of heavy metals (HM) in surface water for irrigation purposes with associated human health risks and pollution sources near the marble industry in Malakand, Pakistan. Twenty-seven water samples were randomly collected and analyzed for HM concentration by inductively coupled plasma‒optical emission spectrometry (ICP‒OES). pH, electrical conductivity (EC), total dissolved solids (TDS), biological oxygen demand (BOD), and chemical oxygen demand (COD) were measured using standard methods of American Public Health Association (APHA). Irrigation suitability was assessed using specific water quality parameters. The associated health risks from ingestion and dermal exposure to heavy metals were calculated by USEPA health risk indices. Pollution sources and spatial distribution mapping were studied using compositional data analysis (CoDa) and the application of a geographic information system (GIS) to understand the changing behavior of heavy metals in surface waters. The concentrations of BOD (89%), COD (89%), Al (89%), Ca (89%), Cr (56%), Cu (78%), Fe (56%), K (34%) Mg (23%), Mn (56%), Na (89%), Ni (56%), P (89%), and Zn (11%) exceeded the safety limits of National Environmental Quality standards (NEQs) of Pakistan. The results of Kelly's ratio (KR) classified surface water as unsuitable for irrigation. The average daily doses (ADD, mg/kg/day) for Al, Cu, Cr, Fe, Mn, Ni, and Zn were higher in children than in adults. The hazard index (HI) for children and adults was above the threshold (HI > 1), indicating a significant risk of non-carcinogenic toxicity. The carcinogenic risk values for Cr and Ni were above the USEPA limit (1 × 10-6 to 1 × 10-4), suggesting a potential carcinogenic risk for the target population. Principal component analysis (PCA), biplot (CLR), and the CoDa-dendrogram allowed for the identification of elemental associations, and their potential source was anthropogenic rather than natural in origin. Regular monitoring and phytoremediation strategies are proposed to safeguard crops and human health.

Contamination, Source Identification, Ecological and Human Health Risks Assessment of Potentially Toxic-Elements in Soils of Typical Rare-Earth Mining Areas

The mining and leaching processes of rare-earth mines can include the entry of potentially toxic elements (PTEs) into the environment, causing ecological risks and endangering human health. However, the identification of ecological risks and sources of PTEs in rare-earth mining areas is less comprehensive. Hence, we determine the PTE (Co, Cr, Cu, Mn, Ni, Pb, Zn, V) content in soils around rare-earth mining areas in the south and analyze the ecological health risks, distribution characteristics, and sources of PTEs in the study area using various indices and models. The results showed that the average concentrations of Co, Mn, Ni, Pb and Zn were higher than the soil background values, with a maximum of 1.62 times. The spatial distribution of PTEs was not homogeneous and the hot spots were mostly located near roads and mining areas. The ecological risk index and the non-carcinogenic index showed that the contribution was mainly from Co, Pb, and Cr, which accounted for more than 90%. Correlation analysis and PMF models indicated that eight PTEs were positively correlated, and rare-earth mining operations (concentration of 22.85%) may have caused Pb and Cu enrichment in soils in the area, while other anthropogenic sources of pollution were industrial emissions and agricultural pollution. The results of the study can provide a scientific basis for environmental-pollution assessment and prevention in rare-earth mining cities.

Evaluation and environmental risk assessment of heavy metals in the soil released from e-waste management activities in Lahore, Pakistan

In developing regions, electronic waste either gets recycled by using crude and primitive techniques in recycling centers or dumped in dumping grounds that result in the leaching of heavy metals into the ambient environment. The objective of this study is to determine the concentration of heavy metals (Cu, Pb, Zn, Cd, Mn, and Fe) in the surface soil of recycling centers and dumping sites in Lahore, Pakistan, and to quantify and compare the environmental risk. The mean concentration (mg/kg) of Cu, Pb, Zn, and Cd was 722.96, 446.81, 378.76, and 4.11, respectively in the surface soil of recycling centers, and only the mean concentration of Cu (214.09 mg/kg) from dumping sites were above permissible limits of World Health Organization. Results of the geo-accumulation index (Igeo) and contamination factor (Cf) revealed that the surface soil is highly contaminated with Cu, Pb, and Cd. The Cd content (701.24) caused a very high potential ecological risk (Er) (> 320) to nearby biological communities. The noncarcinogenic risk was only expected from Pb to children (1.70) living near recycling centers, whereas no risk was observed for adults living either near recycling centers (0.23) or dumping sites (0.01). There is a high probability of carcinogenic health risks to children (1.085 × 10^-2) and adults (1.195 × 10^-3) from Cu. Hence, all the results suggest that e-waste recycling and dumping activities were a significant source of heavy metals to the surrounding environment, children, and adults, so it is strongly recommended to take action for sustainable management of e-waste.

Widespread occurrence of microplastics in marine bays with diverse drivers and environmental risk

Microplastic contamination in the sediment of marine bays has attracted widespread attention, whereas the distribution, sedimentation, morphology and risk of microplastics at regional scale remain poorly understood. By introducing a data mining framework into microplastic research, we compiled a microplastic dataset of 649 samples from 24 bays to enhance the understanding of geographical difference and drivers, transfer, composition profile and environmental risk of sedimental microplastics. Microplastic abundance varied from 0.72 to 1963.96 items/kg dry weight, with higher concentrations mainly occurring in East Asian bays. The spatial pattern in abundance was driven by the river plastic emissions, aquaculture production and hydrodynamic condition. A significantly positive correlation between microplastic abundance in water and sediment was found, and microplastic sedimentation was related to polymer density, hydrodynamic conditions and sediment properties. The dominant shape and polymer of sedimental microplastics were fiber and polypropylene, respectively, and the similarity of microplastic composition decreased with increasing geographical distance. The environmental risks of microplastics were partitioned into three classes (Rank II-Rank IV) with a two-dimensional assessment system considering the bioavailability and toxicity of microplastics, and Asian bays were identified as potential high-risk areas. To reduce the environmental risk of sedimental microplastics in bays, priority should be given to the removal of microfibers, and control measures depend on the risk classes and dominant polymers. Microplastic abundance and composition were significantly affected by methodological choices regarding sampling, pretreatment and identification, suggesting a unified methodology is essential to further enhance our knowledge on the distribution and risk of microplastics in marine bays.

Novel insights into probabilistic health risk and source apportionment based on bioaccessible potentially toxic elements around an abandoned e-waste dismantling site

The study of potentially toxic element (PTE) hazards around e-waste recycling areas has attracted increasing attention but does not consider elemental bioaccessibility. Here, the respiratory and oral bioaccessibilities were incorporated into probabilistic health risk evaluation and source contribution apportionment. The results showed that soil Cd yielded the highest respiratory and oral bioaccessibility, whereas Cr in soils and vegetables attained the lowest oral bioaccessibility. When incorporating metal bioaccessibility into health risk assessment, a 48.3%-55.7% overestimation of non-cancer and cancer risks can be avoided relative to the risk assessment based on the total concentrations of PTEs. More importantly, priority control metals were misidentified without consideration of bioaccessibility. Cadmium, As, and Cr were screened as the priority metal(loid)s for targeted risk control based on the total PTEs, whereas Cd, Zn, and Cu were the priority metal(loid)s based on the bioaccessible PTEs. Furthermore, source apportionment revealed that >50% of oral bioaccessible Cd, Cu, Ni, Pb, and Zn in farmland were contributed by e-waste dismantling activities, whereas bioaccessible As and Cr mainly originated from agrochemical applications and natural sources, respectively. This study emphasizes the refinement of risk estimation and source apportionment through metal bioaccessibility adjustment, which facilitates the realistic assessment of adverse health effects in humans and the precise identification of high-risk sources.

Source, Distribution, and Risk Estimation of Hazardous Elements in Farmland Soils in a Typical Alluvial-Lacustrine Transition Basin, Hunan Province

Increased concentrations of heavy metals in soil due to anthropogenic activities pose a considerable threat to human health and require constant attention. This study investigates the spatial distribution of heavy metals (Cd, Pb, Zn, Sb) and metalloids (As) in a typical alluvial-lacustrine transition basin and calculates the bioavailable forms of elements posing a direct threat. Qualitative and quantitative methods were used to identify the sources of contaminants, after which an ecological risk assessment was conducted. Total (T) As, Pb, and Zn decreased with the depth, whereas Cd and Sb increased in surface (0-20 cm) soil. Bioavailable (Bio) Cd and Pb in the topsoil were regulated by pH and organic matter, whereas Bio-Zn was regulated by soil pH. Within deeper soil layers, the combined effects of pH, organic matter, and clay contents regulated the bio-elements. The results of multiple methods and local investigation showed that TSb (65.3%) was mainly derived from mining activities, TCd (53.2%) and TZn (53.7%) were derived from direct pollution by industrial production and agricultural fertilizers, respectively, and TA (55.6%) was mainly derived from the soil parent material. TPb was related to vehicle exhaust emissions and atmospheric deposition from industrial activities. Although the potential ecological risk in the study area remains relatively low, there is a need for continuous monitoring of the potential ecological risks of Cd and Sb. This study can act as a reference for the prevention and mitigation of heavy metal contamination of alluvial-lacustrine transition basins.

Ecological and human health risk assessment of heavy metals based on their source apportionment in cropland soils around an e-waste dismantling site, Southeast China

An accurate understanding of soil heavy metal (HM) pollution characteristics and source apportionment, and a recognition of the major factors influencing ecological and human health risks (HHRs) are essential for soil HM pollution control and remediation. In this study, 212 surface soils (0-20 cm) and 15 profile soils (0-100 cm) were collected from cropland soils around an e-waste dismantling site in Taizhou city, Zhejiang Province, China. Spatial analysis was used to evaluate the pollution characteristics of HMs (Cd, Cu, Pb, Zn, Cr and Ni). Principal component analysis (PCA) and positive matrix factorization (PMF) were also conducted to quantify their source contributions. A modified source-oriented HHR assessment integrated source-oriented ecological risk and source-oriented HHR assessment was developed to describe the major factors that influenced HHR. Results showed that 94.81 %, 88.21 %, 36.79 % and 47.17 % of Cd, Cu, Pb and Zn, respectively, in surface soils exceeded their screening values in the soil environmental quality standard for agricultural soils (GB 15618-2018). Spatial analysis indicated that high values of Cd, Cu, Pb and Zn were distributed near the e-waste dismantling site. The results of PCA and PMF showed that the primary sources of HMs in the study area are e-waste dismantling activities, natural sources and atmospheric deposition, which contribute 27 %, 46 % and 27 % of HM pollutants, respectively. The results of source-oriented ecological risk and HHR assessment indicated that e-waste dismantling activities and natural sources were primary sources for ecological risk and HHR. However, source-oriented HHR assessment may underestimate the contribution of e-waste dismantling activities by ignoring HM pollution levels. The modified source-oriented HHR assessment highlights that e-waste dismantling activities were major factor that affect noncarcinogenic risk. This study could provide important data support for subsequent environmental remediation of soil HM pollution in cropland soils around e-waste dismantling sites.

Circular economy strategy and waste management: a bibliometric analysis in its contribution to sustainable development, toward a post-COVID-19 era

A descriptive analysis of 416 documents was performed using bibliometric techniques, in order to gather existing knowledge in circular economy focusing on waste management (2007-2020). The results of this study indicate that annual scientific production increased 94% in the last 5 years, highlighting the countries of Italy, Spain, the UK, China, Brazil, and India. Between the most cited documents stand out those related to calorific value of municipal solid waste and waste to energy technologies for achieving circular economy systems. The conceptual analysis indicates strong linkage between circular economy and sustainable production, waste management, and recycling. Emerging research trends evolved from processes and industry-oriented approach (2017) toward waste management, recycling, and circular economy (2019) and sustainable development and urban solid waste (2020). The analysis reveals five dominant circular economy and waste research themes: (1) greenhouse gases; (2) circular economy, waste management, and recycling; (3) life cycle; (4) waste treatment; and (5) anaerobic digestion and recovery; trends research are related to policy interventions, and enforcement of authorities' regulations to foster circular economy transition, increase the use of practices of recycling and reusing, as well as discourage a growing consumption culture. Results found denote the challenge represented by the implementation of comprehensive policies in circular economy. The above being a key alternative for green recovery in response to the current COVID-19 pandemic.

Co-high-efficiency washing agents for simultaneous removal of Cd, Pb and As from smelting soil with risk assessment

Soil washing is considered a highly efficient technology due to its higher removal rate of multiple heavy metals from contaminated soil. However, previous studies on Cd, Pb and As washing agents for soils with complex contaminations did not consider the differences in As and Cd/Pb properties, resulting in the lack of effective washing compounds and washing conditions for soils with complex contaminations. Moreover, most traditional washing agents can cause secondary pollution. In this study, HEDTA and lactic acid (LA) treatments resulted in a higher Cd and Pb removal, while 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) was more effective in As removal. Most importantly, a new washing strategy was proposed with a new combined high-efficiency washing agents consisting of HEDP + LA + FeCl₃ with a ratio of 6:3:1. Considering washing efficiency and consumption under optimal washing conditions, i.e. the soil/liquid (S/L) ratio of 1:20 and washing time of 48 h, the rates of Cd, Pb and As removal were 79.93%, 69.84% and 61.55%, respectively. In addition, washing process could influence the speciation of heavy metals, especially oxidizable and residual Cd and Pb fractions, as well as reducible As fraction. The washing process using the new washing agent can significantly reduce the pollution level and health risk of Cd, Pb and As contamination. The results of this study can provide an efficient washing agent for the remediation of heavy metal-contaminated soils at smelting sites, which will help protect human health.

Pollution status, health risk assessment of potentially toxic elements in soil and their uptake by gongronema latifolium in peri-urban of Ora-Eri, south-eastern Nigeria

Pollution monitoring of potentially toxic elements (PTEs) in a typical peri-urban area in Ora-Eri, Nigeria has been unchecked. Thus, unified evaluation process was developed to assess the pollution load index and potential health risk to inhabitants in mapped regions. The environmental risk was evaluated using contamination factor, geo-accumulation index and Nemerow integrated index. The source of heavy metal pollution was identified by Pearson correlation statistics. Public health risk caused by intake of leafy vegetables and soil exposure were estimated in regard to location of the farmland. The soil was non-contaminated by lead (Pb), arsenic (As), selenium (Se) and chromium (Cr) but gongronema latifolium was contaminated with As exceeding WHO/FAO limit. The bioaccumulation of PTEs in the vegetable follows this order: Se > Pb > As > Cr. The retention of selenium in leaf is high because is an essential metalloid. The pollution status of the studied locations ranged from low to moderate. Arsenic is the main contributor to the ecological contamination. The potential hazard health risk ranged from 5.37E-03 to 2.75E-02 for adults and 5.40E-02 to 2.60E-01 for children. The cancer risk for adults (2.43E-06 to 1.24E-05) and children (8.75E-05 to 1.15E-04) exceeded the acceptable standard (1 × 10⁻⁶) signifying gradual cancer effects. Therefore, the estimated hazard index and total cancer risk revealed that children are more prone to potential health risk than adults. Nevertheless, further continuous works should be carried out to monitor health risk in humans especially children and the control management policy of the peri-urban area should be adopted.

Heavy metal pollution in the soil of a riverine basin: distribution, source, and potential hazards

Soil pollution with heavy metals (HMs) has become a world environmental problem. This study focuses on surface soil contamination with Cr, Mn, Co, Ni, Cu, Zn, Cd, Hg, Pb, Fe, and Al, their sources, and potential hazards along the basin of River Swat, Pakistan. The average concentrations (mg/kg) of HMs were the most abundant for Al (24,730.19) followed by Fe (22,419.41) > Mn (386.78) > Zn (57.75) > Cr (38.07) > Ni (32.46) > Cu (23.43) > Pb (19.59) > Co (10.77) > Cd (3.18) > Hg (0.12). The concentrations of Cr and Mn in 5.45% each, Co in 10.90%, Zn in 27.27%, Cu in 36.36%, Ni in 41.81%, and Hg in 92.72% of the total soil samples exceeded their respective background values. The geostatistical approaches determined the distribution patterns of HM pollution along the basin, whereas the statistics of principal component analysis exposed the likely sources of HM contamination in the area. Pollution indices evaluated the overall HM distribution and pollution status in the area. Contamination factor showed a high degree of HM contamination in 82% of the total sampling sites, while the geo-accumulation index designated low to moderate contamination with Cr, Mn, Co, Ni, Cu, Zn, Hg, and Pb, and moderate to extreme contamination with Cd, Fe, and Al. The trend of ecological toxicity showed potential ups and downs along with the sites from low to considerable hazard (< 95 < PEHI < 190), whereas the human carcinogenic hazard was within the USEPA acceptable limits (1 × 10^-7-1 × 10^-4), but the non-carcinogenic hazard was higher than the threshold (HI > 1) for children because they are more exposed than adults.

Spatial variation of heavy metals and their ecological risk and health risks to local residents in a typical e-waste dismantling area of southeastern China

There is an increasing concern that soils in e-waste recycling regions are severely contaminated by unregulated e-waste dismantling activities. Hence, it is urgent to reveal the spatial variation of hazardous elements in arable lands close to e-waste stacking and dismantling areas and their potential risks to human beings. We collected 349 topsoil samples based on an intensive grid of 100 m × 100 m in southeastern China. The average concentrations of heavy metals were 1.25 (Cd), 35.44 (Ni), 77.68 (Cr), 77.38 (Pb), 122.14 (Cu), 203.39 (Zn), 0.21 (Hg), and 4.74 (As) mg kg^-1, respectively. Compared to the risk screening values of hazardous elements in Chinese agricultural land, Cd and Cu were severely accumulated in the soils. The results of ecological risk analysis revealed that Cd posed the crucial risk among the studied elements. However, the levels of non-carcinogenic and carcinogenic risk were still within the acceptable quantity for adults. Spatial distribution by kriging interpolation displayed that the heavy metals were mainly distributed close to e-waste dismantling sites.

Inhalation Bioaccessibility and Risk Assessment of Metals in PM2.5 Based on a Multiple-Path Particle Dosimetry Model in the Smelting District of Northeast China

PM2.5 can deposit and partially dissolve in the pulmonary region. In order to be consistent with the reality of the pulmonary region and avoid overestimating the inhalation human health risk, the bioaccessibility of PM2.5 heavy metals and the deposition fraction (DF) urgently needs to be considered. This paper simulates the bioaccessibility of PM2.5 heavy metals in acidic intracellular and neutral extracellular deposition environments by simulating lung fluid. The multipath particle dosimetry model was used to simulate DF of PM2.5. According to the exposure assessment method of the U.S. Environmental Protection Agency, the inhalation exposure dose threshold was calculated, and the human health risk with different inhalation exposure doses was compared. The bioaccessibility of heavy metals is 12.1−36.2%. The total DF of PM2.5 in adults was higher than that in children, and children were higher than adults in the pulmonary region, and gradually decreased with age. The inhalation exposure dose threshold is 0.04−14.2 mg·kg−1·day−1 for the non-carcinogenic exposure dose and 0.007−0.043 mg·kg−1·day−1 for the carcinogenic exposure dose. Cd and Pb in PM2.5 in the study area have a non-carcinogenic risk to human health (hazard index < 1), and Cd has no or a potential carcinogenic risk to human health. A revised inhalation health risk assessment may avoid overestimation.

Prediction of Safety Risk Levels of Veterinary Drug Residues in Freshwater Products in China Based on Transformer

Early warning and focused regulation of veterinary drug residues in freshwater products can protect human health and stabilize social development. To improve the prediction accuracy, this paper constructs a Transformer-based model for predicting the safety risk level of veterinary drug residues in freshwater products in China to conduct a comprehensive assessment and prediction of the three veterinary drug residues with the maximum detection rate in freshwater products, including florfenicol, enrofloxacin and sulfonamides. Using the national sampling data and consumption data of freshwater products from 2019 to 2021, this paper constructs a self-built dataset, combined with the k-means algorithm, to establish the risk-level space. Finally, based on a Transformer neural network model, the safety risk assessment index is predicted on a self-built dataset, with the corresponding risk level for prediction. In this paper, comparison experiments are conducted on the self-built dataset. The experimental results show that the prediction model proposed in this paper achieves a recall rate of 94.14%, which is significantly better than other neural network models. The model proposed in this paper provides a scientific basis for the government to implement focused regulation, and it also provides technical support for the government’s intervention regulation.

Artificial Intelligence-Based Robotic Technique for Reusable Waste Materials

Waste management is a critical problem for every country, whether it is developed or developing. Selecting and managing waste are a critical part of preserving the environment and maximizing resource efficiency. In addition to reducing trash and disposal, reusable items are predicted to be of great benefit since they lessen our dependence on raw materials. The usage of compostable trash may be expanded outside fertilizers and dung after the metallic, chemicals, and glass items have been recycled. After a good scrubbing, the glass may be broken down and remelted to create new items. Reusing waste items via garbage recovery is one of the best methods to do so. This document outlines the steps that must be taken to maximize the use of garbage. This work describes a reusable industrial robot arm for grasping and sorting things depending on the resources they contain. Gripping, motion control, and object material categorization are all integrated into a full-automation, reusable system architecture in this study. LeNet also was adjusted to classify garbage into cartons and plastics using an artificial intelligent technique, with the use of a customized LeNet model. Movement in terms of moving the robot in the most efficient way possible, the robot's grabbing, and categorization were incorporated into the movement design process. The system's grabbing and object categorization success rates and computation time are calculated as metrics for evaluation.

Integrated survey on the heavy metal distribution, sources and risk assessment of soil in a commonly developed industrial area

The Jiangzhe Area was relatively common area that rely on industrial process for rapid development with serious heavy metals contamination. This study investigated the spatial, vertical and speciation distribution, correlation of heavy metals, as well as assessed pollution and health risks in three representative contamination industries at Jingjiang (electroplating site), Taizhou (e-waste recycling site) and Wenzhou (leather production site) in the Jiangzhe Area. The results indicated that the Cr(VI) pollution was serious in all three sites and there was a tendency to gradually decrease with depth. As for other heavy metals, not only the total concentration, but also the addition of acid soluble and reducible speciation generally decreased with soil depth at Jingjiang and Taizhou sites. Significantly positive correlations supported by correlation analysis were detected between the following elements: Cu-Ni (p < 0.01), Cr(VI)-Ni (p < 0.05) and Cr(VI)-Cu (p < 0.05) at Jingjiang site, Cu-Ni (p < 0.01), Cu-Cd (p < 0.01) and Ni-Cd (p < 0.05) at Taizhou site indicating possibly the same sources and pathways of origin, while the significantly negative correlation of Cd-Ni (p < 0.05) at Wenzhou site meaning the different sources. As regards the pollution assessment of topsoil, the mean PI value indicated that Cr(VI) contaminated severe in all three sites. In general, Jingjiang site was severe pollution (4.06), while Taizhou and Wenzhou (2.27 and 2.66) were moderate pollution, as NIPI value shown. In terms of health risk assessment that received much attention, non-carcinogenic risks caused by Pb contamination were significant for children at Jingjiang and Taizhou sites, with the HI values of 3.42E+ 00 and 2.03E+ 00, respectively. Ni caused unacceptable carcinogenic risk for both adults and children at all three sites. The present study can help to better understand the contamination characteristics of heavy metals in the commonly developed industrial area, and thus to control the environmental quality, so as to truly achieve the goal of "Green Deal objectives ".

Assessment of cadmium and lead tolerance potential of quinoa (Chenopodium quinoa Willd) and its implications for phytoremediation and human health

Soil contamination with Cd and Pb is a worldwide problem which not only degrades the environment but also poses a serious threat for human and animal health. Phytoremediation of these contaminated soils using halophytic plants like quinoa presents an opportunity to clean the soils and use them for crop production. The current experiment was performed to evaluate the Cd and Pb tolerance potential of quinoa and subsequently its implications for human health. Three weeks old quinoa seedlings were exposed to Cd (30, 60 and 90 mg kg^-1) and Pb (50, 100 and 150 mg kg^-1) levels along with a control. The results revealed that plant height decreased at highest levels of soil Cd and Pb. Shoot, root and seed dry weight decreased with increasing levels of soil Cd and Pb. Tissue Cd and Pb concentrations increased with increasing levels of Cd and Pb in soil, the highest Cd was found in roots while the lowest in seeds. The highest Pb concentration was found in shoots at low Pb level, while in roots at high level of Pb. Increasing levels of Cd and Pb stimulated the activities of measured antioxidant enzymes and decreased membrane stability index. The health risk assessments of Cd and Pb revealed that hazard quotient was < 1 for both the metals. However, the results of total hazard quotient showed that value was < 1 for Pb and 1.19 for Cd showing potential carcinogenicity. This study demonstrates that quinoa has good phytoremediation potential for Cd and Pb however, the risk of Cd toxicity is challenging for human health.

Assessment of Land Use Pattern and Landscape Ecological Risk in the Chengdu-Chongqing Economic Circle, Southwestern China

The Chengdu-Chongqing Economic Circle (CCEC) is becoming the fourth growth pole in China after the Yangtze River Delta Economic Circle (YRDEC); Guangdong, Hong Kong, and Macao Economic Circle (GBAEC); Beijing, Tianjin, and Hebei Economic Circle (BTHEC). The land use and landscape ecological management of the CCEC is critical to its social and economic development. Using ArcGIS modeling and Fragstats processing methods, we divided the CCEC into 5 km × 5 km ecological risk areas and constructed a landscape ecological risk index evaluation model to calculate the spatial and temporal dynamic changes in the urban expansion and landscape ecological risk over the last 20 years. The results show that the land use was mainly cultivated land, which exhibited a decreasing trend and was mainly converted to construction land and forest land. The change in the construction land exhibited a continuous expansion trend with the dual core in Chengdu-Chongqing. The average risk of 10,155 risk communities was about 0.16. The expansion of human activities increased the landscape ecological risk of the construction land, and the risk of the edge of the cultivated land was higher than the internal risk value. The ecological risk index values of 16 cities in the study area ranged from 0.02 to 0.28. The resistance of the landscape pattern to external disturbance was stronger than that in other regions of China. The landscape ecological risk is controllable overall. However, the higher level of economic development in Chengdu, Chongqing, and other mature cities poses a greater landscape ecological risk. The results of this research provide an important reference for promoting the optimization and construction of the land space in the CCEC, building ecological shelters, and preventing ecological risk in the upper reaches of the Yangtze River.

Integrated assessment of the impact of land use types on soil pollution by potentially toxic elements and the associated ecological and human health risk

The impact of land use type on the content of potentially toxic elements (PTEs) in the soils of the Qinghai-Tibet Plateau (QTP) and the associated ecological and human health risks has drawn great attention. Consequently, in this study, top- and subsurface soil samples were collected from areas with four different land uses (i.e., cropland, forest, grassland, and developed area) and the total contents of Cr, Cd, Cu, Pb and Zn were determined. Geostatistical analysis, self-organizing map (SOM), and positive matrix factorization (PMF), ecological risk assessment (ERA) and human health risk assessment (HRA) were applied and used to classify and identify the contamination sources and assess the potential risk. Partial least squares path modeling (PLS-PM) was applied to clarify the relationship of land use with PTE contents and risk. The PTE contents in all topsoil samples surpassed the respective background concentrations of China and corresponding subsurface concentrations. However, the ecological risk of all soil samples remained at a moderate or considerable level across the four land use types. Developed area and cropland showed a higher ecological risk than the other two land use types. Industrial discharges (32.8%), agricultural inputs (22.6%), natural sources (23.7%), and traffic emissions (20.9%) were the primary PTE sources in the tested soils, which indicate that anthropogenic activities have significantly affected soil PTE contents to a greater extent than other sources. Industrial discharge was the most prominent source of non-carcinogenic health risk, contributing 37.7% for adults and 35.2% for children of the total risk. The results of PLS-PM revealed that land use change associated with intensive human activities such as industrial activities and agricultural practices distinctly affected the PTE contents in soils of the Qinghai-Tibet Plateau.

Security Risk Level Prediction of Carbofuran Pesticide Residues in Chinese Vegetables Based on Deep Learning

The supervision of security risk level of carbofuran pesticide residues can guarantee the food quality and security of residents effectively. In order to predict the potential key risk vegetables and regions, this paper constructs a security risk assessment model, combined with the k-means++ algorithm, to establish the risk security level. Then the evaluation index value of the security risk model is predicted to determine the security risk level based on the deep learning model. The model consists of a convolutional neural network (CNN) and a long short-term memory network (LSTM) optimized by an arithmetic optimization algorithm (AOA), namely, CNN-AOA-LSTM. In this paper, a comparative experiment is conducted on a small sample data set of independently constructed security risk assessment indicators. Experimental results show that the accuracy of the CNN-AOA-LSTM prediction model based on attention mechanism is 6.12% to 18.99% higher than several commonly used deep neural network models (gated recurrent unit, LSTM, and recurrent neural networks). The prediction model proposed in this paper provides scientific reference to establish the priority order of supervision, and provides forward-looking supervision for the government.

Migration and Transformation of Multiple Heavy Metals in the Soil–Plant System of E-Waste Dismantling Site

E-waste generation has become a major environmental issue worldwide. Heavy metals (HMs) in e-waste can be released during inappropriate recycling processes. While their pollution characteristics have been studied, the migration and transformation of different multi-metal fractions in soil–plant system of e-waste dismantling sites is still unclear. In this study, pot experiments were conducted to investigate the migration and transformation of different multi-metal fractions (Cu, Pb, Zn and Al) in the soil–plant system using two Chinese cabbage cultivars (heavy metals low-accumulated variety of Z1 and non-low-accumulated Z2) treated with or without biochar. The result showed that the acid-soluble fraction of Cu, Pb, Zn and Al in soil decreased by 5.5%, 55.7%, 7.8% and 21.3%, but the residual fraction (ResF) of them increased by 48.5%, 1.8%, 30.9% and 43.1%, respectively, when treated with biochar and plants, compared to that of the blank soil (CK). In addition, Pb mainly existed as a reducible fraction, whereas Cu existed as an oxidisable fraction. Biochar combined with plants significantly increased the ResF of multi-metals, which reduced the migration ability of Pb among all other metals. The relative amount of labelled ¹³C in the soil of Z1 was higher than that of Z2 (25.4 fold); among them, the Gram-negative bacteria (18-1ω9c, 18-1ω7c) and fungi (18-2ω6c) were significantly labelled in the Z1-treated soil, and have high correlation with HM migration and transformation. In addition, Gemmatimonadete were significantly positive in the acid-soluble fraction of HMs, whereas Ascomycota mostly contributed to the immobilisation of HMs. Therefore, the distribution of fractions rather than the heavy metal type plays an important role in the HM migration in the soil–plant system of e-waste dismantling sites.

Recent advances in nanoremediation: Carving sustainable solution to clean-up polluted agriculture soils

Agriculture is one of the foremost significant human activities, which symbolizes the key source for food, fuel and fibers. This activity results in a lot of ecological harms particularly with the excessive usage of chemical fertilizers and pesticides. Different agricultural practices have remained industrialized to advance food production, due to the growth in the world population and to meet the food demand through the routine use of more effective fertilizers and pesticides. Soil is intensely embellished by environmental contamination and it can be stated as "universal incline." Soil pollution usually occurs from sewage wastes, accidental discharges or as byproducts of chemical residues of unrestrained production of numerous materials. Soil pollution with hazardous materials alters the physical, chemical, and biological properties, causing undesirable changes in soil fertility and ecosystem. Engineered nanomaterials offer various solutions for remediation of contaminated soils. Engineered nanomaterial-enable technologies are able to prevent the uncontrolled release of harmful materials into the environment along with capabilities to combat soil and groundwater borne pollutants. Currently, nanobiotechnology signifies a hopeful attitude to advance agronomic production and remediate polluted soils. Studies have outlined the way of nanomaterial applications to restore the eminence of the environment and assist the detection of polluted sites, along with potential remedies. This review focuses on the latest developments in agricultural nanobiotechnology and the tools developed to combat soil or land and or terrestrial pollution, as well as the benefits of using these tools to increase soil fertility and reduce potential toxicity.

Establishment and application of risk classification model for lead in vegetables based on spectral clustering algorithms

This study aims to evaluate the risk of lead pollution in 9 kinds of vegetables consumed by residents in 20 provinces/cities of China. Sampling data and vegetable consumption data from 20 provinces/cities in 2019 were used. Combined with dietary exposure assessment, the vegetable categories and provinces were paired, and a risk classification model based on spectral clustering algorithms was proposed. The results of the spectral clustering algorithm showed that the risk level of lead pollution in vegetables can be divided into five levels. The combination of vegetable‐province/cities at the risk level of 1 and 2 accounted for 92.78%, and that at the risk level of 4 and 5 accounted for 2.22%. The high‐risk combinations were fresh edible fungus–Shaanxi, fresh edible fungus–Sichuan, and fresh edible fungus–Shanghai and bean sprouts–Guangdong. In the proposed model, objective data were used as the classification index, and the spectral clustering algorithm was employed to select the optimal risk classification in a data‐driven way. As a result, the influence of subjective factors was effectively reduced, the risk of lead pollution in vegetables was classified, and the results were scientific and accurate. This study provides a scientific basis of supervision priorities for regulatory departments.

Enrichment Evaluation of Heavy Metals from Stormwater Runoff to Soil and Shrubs in Bioretention Facilities

Bioretention facilities with different inflow concentrations, growing media and plants were examined to determine whether the soil in these facilities was polluted with heavy metals and whether runoff had obvious toxic effects on plants. Using Beijing soil background value as the standard, the soils were evaluated by bioaccumulation index and single factor index. The results show that stormwater runoff containing Cu caused slight pollution in soils, and stormwater runoff containing Zn and Pb was not polluted. Nemerow comprehensive index evaluation revealed that the heavy metals content in the facilities containing vermiculite (a yellow or brown mineral found as an alteration product of mica and other minerals, used for insulation or as a moisture-retentive medium for growing plants) and perlite (a form of obsidian characterized by spherulites formed by cracking of the volcanic glass during cooling, used as insulation or in plant growth media) were higher than the standard. High influent concentration caused significantly higher heavy metals content in plants. While Pb accumulation in the two studied plants was the highest, Cu and Zn accumulation, which are essential for plant growth, was relatively low. The contents of the three heavy metals in the studied plants also exceeded their corresponding critical values.

Potential driving forces and probabilistic health risks of heavy metal accumulation in the soils from an e-waste area, southeast China

The integrated analysis of the distribution characteristics, health risks, and source identification of heavy metals is crucial for formulating prevention and control strategies for soil contamination. In this study, the area around an abandoned electronic waste dismantling center in China was selected as the research area. The probabilistic health risks caused by heavy metals were evaluated by the Monte Carlo simulation. Random forest, partial least squares regression, and generalized linear models were utilized to predict heavy metal distributions and identify the potential driving factors affecting heavy metal accumulation in soil. The relationships of spatial variation between the heavy metal contents and environmental variables were further visualized. The results revealed that cadmium (Cd) and copper (Cu) were the primary soil pollutants in the study area and caused high ecological risks. The probabilistic health risk assessment indicated that the non-carcinogenic and carcinogenic risks for all populations were acceptable. However, children are more susceptible to heavy metal soil contamination than adults. The sensitivity analyses indicated that the total contents of soil heavy metals and soil ingestion rate were the dominant factors affecting human health. The random forest model, with R² values of 0.41, 0.65, 0.57, 0.71, and 0.58 for Cd, Cu, Ni, Zn, and Pb, respectively, predicted the heavy metal concentrations better than the other two models. The distance to the nearest industrial enterprise, industrial output, and agricultural chemical input were the main factors affecting Cd, Cu, Zn, and Pb accumulations in the soil, and soil pH and soil parent material were the primary factors influencing Ni accumulation in the soil. The visualization results of the geographically weighted regression model showed a significant relationship between soil heavy metal contents and industrial activity level. This study could be utilized as a reference for policymakers to formulate prevention and control strategies for heavy metal pollution in agricultural areas.

Multi-level methods to quantify risk assessment, source apportionment and identifying key risk areas of soil toxic elements in Ashi River watershed, China

With the advancement of small watershed governance in agricultural production process, soil toxic element pollution issue in watersheds constitutes a recent research hot spot. The Ashi River watershed is an agriculture-dominated small watershed which is exposed to toxic element sources, posing high risk of toxic element pollution to the planting areas. In this study, collection of soil samples was carried out along the periphery of the river network, and the soil physicochemical parameters and toxic elements (As, Cd, Cr, Cu, Pb, and Zn) were analyzed. The results showed that: (1) The geo-accumulation index (I_geo) and potential ecological risk index were used to evaluate the pollution degree, and the contents of As, Cd, and Zn in some sampling sites exceeded risk screening values. Moreover, soils closer to mining sources were found to be more polluted; (2) Redundancy analysis confirmed the contribution rate relationship between environmental factors and toxic elements. C/N ratio, total carbon (C), and total potassium (K) exhibited significant relationships with toxic elements (P < 0.01 or P < 0.05), respectively. Moreover, geographic locations (longitude, latitude, and elevation) showed significant impacts on toxic element contents (except for Cu); (3) The apportionment of toxic element pollution sources by using principal component analysis showed that Pb, Zn, Cu, and Cd were mainly related to mining activities, while As was closely related to insecticide and herbicide, and Cr was mainly related to soil parent material and electroplating factory; (4) Through the integrated resistance base surface and toxic element sources combined with minimum cumulative resistance model, the toxic element risk areas were identified. The middle reaches corresponded to the extremely high risk zone, which undeniably requires the strengthening of the environmental management.

Vertical distribution of the toxic metal(loid)s chemical fraction and microbial community in waste heap at a nonferrous metal mining site

Over the past few decades, nonferrous mining has produced numerous waste rock and part of the waste that has not been properly treated was generally dumped at roadsides and hill slopes. However, the vertical distributions of toxic metal(loid)s and composition of microbial communities in waste heap and the under-laid pristine soil are rarely studied. In this work, the fraction-related distributions of toxic metal(loid)s were investigated at a waste heap profile and the indigenous microbial assemblages were also analyzed by Illumina sequencing of 16 s rRNA genes. Results showed that compared to the under-laid pristine soil, content of toxic metal(loid)s, especially Cd, As and Pb, in waste rock layer were higher. Most of As in subsoil existed as non-specifically sorbed and specifically-sorbed fractions, which could be ascribed to the migration from the upper layer. The mobility was significantly correlated with Eh, EC, clay content, CEC and the total content of metal(loid)s. Phyla Proteobacteria, Acidobacteria and Firmicutes dominated the microbial communities. The microbial community compositions at the genus level were similar, but their relative abundances were mainly influenced by pH, CEC, Eh, SOM, and bioavailability content of toxic metal(loid)s. Besides, microbial functions of elements (S, Fe, Mn and As) oxidation/reduction and metabolites (siderophore, biosurfactant, organic acid, phosphatase and urease) potentially were used for pollutants bioremediation.

Assessment of industrial wastewater for potentially toxic elements, human health (dermal) risks, and pollution sources: A case study of Gadoon Amazai industrial estate, Swabi, Pakistan

In this study, industrial wastewater and groundwater were comparatively investigated for their physicochemical properties, concentrations of potentially toxic elements (PTEs), human health risks and pollution source(s). Every month, 34 wastewater samples and 26 groundwater samples were collected, for a duration of one year. The results showed that the physicochemical parameters and concentrations of PTEs in the industrial wastewater exceeded the maximum permissible limits of Pakistan Environmental Protection Agency (2000). Specifically, it was found that total dissolved solids (5%), total suspended solids (190%), chemical oxygen demand (107%), five-days biochemical oxygen demand (5.7 times), grease/oil (27.1 times), Fe (67%), Zn (29%), Mn (32%), Cu (27%), Ni (16%), Cr (8%), Pb (106%), and Cd (80%) were higher than the permissible limits. The carcinogenic and non-carcinogenic dermal health risks for wastewater irrigation group were significantly higher than the groundwater irrigation group. The hazard index of irrigation with industrial wastewater was 180 times higher than the groundwater. The principal component analysis indicated that industry was the main polluting source. The cluster analysis results of all PTEs (except Fe) were found in the same clade in the dendrogram, which showed a strong similarity within the monthly data set of the whole year. The study recommends using adjacent groundwater instead of industrial wastewater for irrigation purposes.

Characterization and photodegradation pathway of the leachate of Matuail sanitary landfill site, Dhaka South City Corporation, Bangladesh

This study was carried out to characterize the biogeochemical and physicochemical properties of landfill leachate from Matuail Sanitary landfill site, Dhaka, Bangladesh. In addition, the study also aimed to identify the photodegradation of landfill leachate under natural sunlight. The leachate pH was slightly alkaline (7.87–8.07) with a minimum level of dissolved oxygen, and low BOD₅/COD ratio that are indicators of the matured methanogenic phase. Ca, Fe, Br, Rb, Cu was present in a considerable amount. A trace amount of Sr, Co, As, Pb, Cr was found in the leachate sample. Fourier Transform - infrared (FTIR) spectra of all three samples had five major peak regions notably at 3440–3450 cm⁻¹ (O–H groups of water), 1638 cm⁻¹ (C=O Amide I, carboxylates C=C, aromatic ring modes, or alkenes), 1385–1390 cm⁻¹ (deformation of the C–H bond in CH₂ and CH₃, or the asymmetric stretching of COO¯), 1115 cm⁻¹ (stretching of the C–O bond in phenol ethers and phenols) and 605 cm⁻¹ (S–O bends of sulfates). In addition to the appearance of new peak, peak shifting on the 2^nd-day and 5^th-day phototreatment are in compliance with the 34% TOC reduction. From analyzing three-dimensional excitation/emission (3D-EEM) spectra of the raw sample pyrene-like or humic-like peak A (Ex 255/Em 465), soil fulvic-like peak M_p (Ex 315/Em 450), and humic-like peak C (Ex 370/Em 455) was found indicating more humified characteristics of the mature landfill site. From 1-hour to 6-hours phototreatment, all three substances slightly lost fluorescence intensity. From the 2^nd day to the 5^th day of photo-treatment, two unknown photo-product was identified within Ex 210/Em 457 and Ex 205/Em 408 at peak A region. Fluorescence intensity lost was 65% for peak A and 44% for peak C. Soil fulvic-like peak M_p was absent on the 5^th day of photo-treatment.

Heavy metals in soil-vegetable system around E-waste site and the health risk assessment

Investigating the farmland quality around electronic waste (E-waste) dismantling site and taking positive measures to ensure local food safety are urgent. Eleven types of vegetables (n = 184) and their corresponding soils were collected from vegetable fields in a city with famous historical e-waste activities in China. Nemerow integrated pollution indices analysis revealed that local vegetable fields suffered from heavy metal pollution to a certain extent, especially with regards to Cd, Cu, and Zn. The human health risk models provided by USEPA have been used to evaluate the non-carcinogenic and carcinogenic risks associated with the consumption of vegetables by local residents. Results indicated that both adults and children were suffering potential health risks. And the consumption of lettuce and sweet potato caused the greatest health risk, whereas cabbage and cowpea were relatively safe. The bioaccumulation factors (BAF) of heavy metals in various vegetables were calculated, and different vegetables showed huge variance in metal accumulation. Considering both contamination status and health risk assessment, cabbage and cowpea were selected as low accumulators of heavy metals. This study reveals the need for adjusting plantation structure and applying amendments to current protocols to alleviate the adverse effects caused by soil pollution.

The application of urban anthropogenic background to pollution evaluation and source identification of soil contaminants in Macau, China

The anthropogenic background characterized by the accumulation characteristics of contaminants is recognized as an important evidence in pollution assessment and source identification in urban soil due to its less arbitrariness compared with the existing quality standards and the guidelines. A credible approach for pollution index calculation referring to anthropogenic background values (ABVs) combined with entropy weight method was developed. By the approach, the soil pollution degrees in Macau, China (one of the most densely populated region worldwide) were assessed based on the database of the heavy metals, Cd, Cu, Hg, Pb, and Zn, and high molecular weight polycyclic aromatic hydrocarbons (HMW PAHs) from 31 sites spatially distributed all over Macau. It was revealed that approximately half of the sites had no specific point source pollution. Mercury, benzo(a)anthracene (BaA), fluoranthene (FLT), and benzo(b)fluorantene (BbF), which had the highest weights were considered as the main contaminants. Macau Peninsula was identified as the critical polluted area. Then, the positive matrix factorization (PMF) coupled with ABVs as one of the data uncertainty inputs was used to identify the anthropogenic pollution sources of the contaminants. Three main anthropogenic sources with their contributions, including vehicle emissions (51.3%), use of hazard material (24.8%), and municipal or domestic waste (23.9%), could be well identified and quantified in the study area. The error estimation of the results showed that the variation of the contaminants in the derived factors were stable. The approaches which were in conformity with ABVs of soil contaminants are proved applicable in soil pollution assessment and source identification.

The Interactions Between Antibiotic Resistance Genes and Heavy Metal Pollution Under Co-Selective Pressure Influenced the Bio-Enzyme Activity

The spread of antibiotic resistance genes (ARGs) has brought potential risks to public health. However, the interactions between heavy metals and ARGs, as well as their potential effect on bio-enzyme activity under the pressure of co-selectivity in soil still remain poorly understood. In this work, the distribution characteristics and the co-selective relationship of 28 ARGs and eight heavy metals in soil in a dairy farm were visualized via the geographic information system (GIS) technique. Eight kinds of heavy metals were detected by an atomic fluorescence spectrometer and atomic absorption spectrophotometer, which were further evaluated via the single factor pollution index value. The GIS analysis showed that arsenic (As) was the key element responsible for soil pollution, which was found to be positively related to soil depths. The top three comprehensive scores of ARGs ranked the orders of sul2 > tetX > blaTEM, indicating the high potential of risk caused by these genes in the soil environment. In addition, the functional predications performed with the 16 SrDNA sequencing data based on the KEGG database indicated that the sulfonamides in soil involved multiple pathways, especially the metabolism, transport and catabolism, and membrane transport processes. This suggested that most bio-enzymes were found to be expressed in low activities in different pathways. Significant correlations were observed between the heavy metals and ARGs (p < 0.05), particularly between the ARGs and As, Cu, Ni, Pb, and Zn (p < 0.01). This study offers deep insights into the potential interactions between heavy metals and ARGs in soil and provides guidance for the fabrication of enzyme-based smart materials for soil remediation in dairy farms.

Source Analysis and Human Health Risk Assessment Based on Entropy Weight Method Modification of PM2.5 Heavy Metal in an Industrial Area in the Northeast of China

In this study, PM2.5 was analyzed for heavy metals at two sites in industrial northeast China to determine their sources and human health risks during heating and non-heating periods. A positive matrix factorization (PMF) model determined sources, and US Environmental Protection Agency (USEPA) and entropy weight methods were used to assess human health risk. PM2.5 heavy metal concentrations were higher in the heating period than in the non-heating period. In the heating period, coal combustion (59.64%) was the primary heavy metal source at Huagong Hospitals, and the contribution rates of industrial emissions and traffic emissions were 21.06% and 19.30%, respectively. Industrial emissions (42.14%) were the primary source at Xinqu Park, and the contribution rates of coal combustion and traffic emissions were 34.03% and 23.83%, respectively. During the non-heating period, coal combustion (45.29%) and industrial emissions 45.29% and 44.59%, respectively, were the primary sources at Huagong Hospital, and the traffic emissions were 10.12%. Industrial emissions (43.64%) were the primary sources at Xinqu Park, where the coal combustion and traffic emissions were 25.35% and 31.00%, respectively. In the heating period, PM2.5 heavy metals at Xinqu Park had noncarcinogenic and carcinogenic risks, and the hazard index of children (5.74) was higher than that of adult males (5.28) and females (4.49). However, adult males and females had the highest lifetime carcinogenic risk (1.38 × 10−3 and 1.17 × 10−3) than children (3.00 × 10−4). The traditional USEPA and entropy weight methods both produced reasonable results. However, when there is a difference between the two methods, the entropy weight method is recommended to assess noncarcinogenic health risks.