Risk assessment from exposure to arsenic, antimony, and selenium in urban gardens (Madrid, Spain)

Evaluating the health risks of heavy metal pollution in dust storms in the city of Erbil in the Kurdistan region of Iraq

This study examined the heavy metal content in dust storm samples from Erbil, Iraq, along with four other locations. Using ICP-MS, Cd, Ni, Cr, Hg, Pb, Zn, Mn, Cu, Co, Fe and As were determined. The health risks due to exposure to these metals through ingestion, inhalation and dermal contact were assessed for both adults and children. Non-carcinogenic risks were evaluated using the hazard quotient (HQ) and hazard index (HI). Children faced a cumulative risk with HQ > 0.2 for As and Cr and HI > 1. The carcinogenic risk was measured using the carcinogenic risk factor (CRF), which fell below 10-6, indicating low cancer risk. However, children had a higher cancer risk (10-4 to 10-6) for As. The pollution indices revealed varying pollution levels from unpolluted to moderately polluted in the studied areas. Overall, this study highlights potential health risks associated with heavy metal exposure during dust storms, particularly for children, and emphasises the importance of addressing these concerns to safeguard public health.

New insights into assembly processes and driving factors of urban soil microbial community under environmental stress in Beijing

Rapid urbanization leads to drastic environmental changes, directly or indirectly affecting the structure and function of soil microbial communities. However, the ecological response of soil microbes to environmental stresses has not yet been fully explored. In this study, we used high-throughput sequencing to analyze the assembly mechanism and driving factors of soil microbial community under environmental stresses. The results indicated that environmental stresses significantly affected soil properties and the levels of beryllium, cobalt, antimony, and vanadium contamination in soil generally increased from the suburban areas toward the city core. The composition and distribution of soil microbial communities demonstrated clear differences under different levels of environmental stress, but there was no significant difference in microbial diversity. Random forest and partial least squares structural equation modeling results suggested that multiple factors influenced microbial diversity, but antimony was the key driver. The influence of environmental stress led to deterministic processes dominating microbial community assembly processes, which promoted the regional homogenization of soil microbes. Therefore, this study provides new insights into urban soil microbial management under environmental stresses.

Is it healthy urban agriculture? Human exposure to potentially toxic elements in urban gardens from Andalusia, Spain

Different vegetable species and topsoils were collected from different urban gardens of Seville, Cordoba, and Huelva (South Spain) and from two small towns in a mining area (Riotinto), together with topsoil close to the plants. The concentration of potentially toxic elements (PTEs) (As, B, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, and Zn) was evaluated in edible plant parts and in the soils. The same species were also purchased from Seville local markets and from a peri-urban area (domestic garden in a rural area) and also analyzed. Plant/soil pollution relation was studied and human health risk was assessed by different parameters. Soils of urban gardens from the mining area were more contaminated with As, Cr, Cu, Pb, and Zn in comparison with other locations, and generally, soils from cities showed higher values of As, Pb, and Zn than the peri-urban ones. The mean concentration of almost all potentially toxic elements was higher in leafy than in fruiting and bulbous species. Arsenic, Cd, and Pb concentrations were below health-based guidance values in all vegetables except Cd in one sample in the peri-urban area. In general, PTEs concentration in vegetables from city urban gardens did not exceed the one found in market vegetables for almost all studied elements, except in lettuce for almost elements. The hazard quotient (HQ) values were lower than the unit for all PTEs in plant species from the studied gardens, as well as the hazard index (HI), indicating that consumption of these vegetables can be considered safe and without risk to human health. Also, cancer risk values for As were below the established limits in all vegetables from the studied urban gardens, including those from the As-contaminated soils in the mining area.

Removal of antimonate (Sb(V)) from aqueous solutions and its immobilization in soils with a novel Fe(III)-modified montmorillonite sorbent

Over the past decades, contamination of terrestrial environments with antimony (Sb) has aroused a great deal of public concern. In this research, the efficacy of Fe(III)-modified montmorillonite (Mt) (Fe-Mt) for the removal of Sb(V) from aqueous solutions with Sb(V) concentration in the range of 0.2-1 mmol L^-1 and immobilization of Sb(V) in soils spiked with 250 mg Sb(V) kg^-1 was investigated. The immobilizing mechanisms of the modified clay were assessed by fitting the experimental sorption data with the Langmuir and Freundlich sorption models and a series of single and sequential extraction studies. The results showed that the adsorption data had a better fit with the Langmuir equation (R²: 0.99) and Fe-Mt could efficiently remove up to 95% of Sb(V) at lower concentration ranges. The concentrations of Sb(V) in exchangeable fraction of modified Community Bureau of Reference (BCR) sequential extraction and distilled water extracts of the amended soils decreased dramatically by up to 60% and 92%, respectively. Furthermore, the bioaccessibility of Sb(V) in simulated human gastric juice reduced remarkably by 52% to 60%, depending upon the soil fraction sizes. The results confirmed that Fe-Mt could be a promising candidate for the removal of Sb(V) from aqueous solutions and immobilization of Sb(V) in terrestrial environments.

A geostatistical approach to estimating source apportionment in urban and peri-urban soils using the Czech Republic as an example

Unhealthy soils in peri-urban and urban areas expose individuals to potentially toxic elements (PTEs), which have a significant influence on the health of children and adults. Hundred and fifteen (n = 115) soil samples were collected from the district of Frydek Mistek at a depth of 0-20 cm and measured for PTEs content using Inductively coupled plasma-optical emission spectroscopy. The Pearson correlation matrix of the eleven relevant cross-correlations suggested that the interaction between the metal(loids) ranged from moderate (0.541) correlation to high correlation (0.91). PTEs sources were calculated using parent receptor model positive matrix factorization (PMF) and hybridized geostatistical based receptor model such as ordinary kriging-positive matrix factorization (OK-PMF) and empirical Bayesian kriging-positive matrix factorization (EBK-PMF). Based on the source apportionment, geogenic, vehicular traffic, phosphate fertilizer, steel industry, atmospheric deposits, metal works, and waste disposal are the primary sources that contribute to soil pollution in peri-urban and urban areas. The receptor models employed in the study complemented each other. Comparatively, OK-PMF identified more PTEs in the factor loadings than EBK-PMF and PMF. The receptor models performance via support vector machine regression (SVMR) and multiple linear regression (MLR) using root mean square error (RMSE), R square (R2) and mean square error (MAE) suggested that EBK-PMF was optimal. The hybridized receptor model increased prediction efficiency and reduced error significantly. EBK-PMF is a robust receptor model that can assess environmental risks and controls to mitigate ecological performance.

The Safe Urban Harvests Study: A Community-Driven Cross-Sectional Assessment of Metals in Soil, Irrigation Water, and Produce from Urban Farms and Gardens in Baltimore, Maryland

BACKGROUND

Emerging evidence suggests social, health, environmental, and economic benefits of urban agriculture (UA). However, limited work has characterized the risks from metal contaminant exposures faced by urban growers and consumers of urban-grown produce.

OBJECTIVES

We aimed to answer community-driven questions about the safety of UA and the consumption of urban-grown produce by measuring concentrations of nine metals in the soil, irrigation water, and urban-grown produce across urban farms and gardens in Baltimore, Maryland.

METHODS

We measured concentrations of 6 nonessential [arsenic (As), barium (Ba), cadmium (Cd), chromium (Cr), lead (Pb), nickel (Ni)] and three essential [copper (Cu), manganese (Mn), zinc (Zn)] metals in soil, irrigation water, and 13 types of urban-grown produce collected from 104 UA sites. We compared measured concentrations to existing public health guidelines and analyzed relationships between urban soil and produce concentrations. In the absence of guidelines for metals in produce, we compared metals concentrations in urban-grown produce with those in produce purchased from farmers markets and grocery stores (both conventionally grown and U.S. Department of Agriculture-certified organic).

RESULTS

Mean concentrations of all measured metals in irrigation water were below public health guidelines. Mean concentrations of nonessential metals in growing area soils were below public health guidelines for Ba, Cd, Pb, and Ni and at or below background for As and Cr. Though we observed a few statistically significant differences in concentrations between urban and nonurban produce items for some combinations, no consistent or discernable patterns emerged.

DISCUSSION

Screening soils for heavy metals is a critical best practice for urban growers. Given limitations in existing public health guidelines for metals in soil, irrigation water, and produce, additional exposure assessment is necessary to quantify potential human health risks associated with exposure to nonessential metals when engaging in UA and consuming urban-grown produce. Conversely, the potential health benefits of consuming essential metals in urban-grown produce also merit further research. https://doi.org/10.1289/EHP9431.

Multiple exposure pathways and health risk assessment of selenium for children in a coal mining area

Selenium (Se) presents a dual role to human body, harmful or beneficial, depending on its concentration. The exposure to this element has been associated to coal mining. Health risk assessment allows estimating and evaluating the risks that environmental hazards pose to vulnerable groups of populations. The present study aimed to analyze the risk of exposure to Se through multiple exposure pathways in children living in Candiota city, where the largest coal reserve of Brazil is located. Data from previous environmental (air, soil, drinking water, and food) and population parameters (age, weight, and food intake) were used to assess the health risk, which was calculated with real values (extracted from the population) and fixed reference values, based on the USEPA recommendation. Most of the children had low health risk (HQ < 1); however, in the most conservative scenarios (higher Se values in the different matrices), there was a high health risk in both scenarios, using population data or the USEPA parameters. The mean HQ using reference values was twice higher than using real values. Se content in air, soil, and drinking water did not represent important average daily dose in both scenarios. While, food intake was a main source of Se exposure, contributing with 96.9% of total Se intake. The findings of this study reinforce the importance of food intake for exposure to Se and the difference between HQs using population measures and fixed parameters of the USEPA highlights the need for adaptations to local scenarios for a better dimensioning of toxicological risk management actions.

The influence of different antimony (Sb) compounds and ageing on bioavailability and fractionation of antimony in two dissimilar soils

Assessing the bioavailability of various Sb substances plays a crucial role in human health and the ecological risk assessment of contaminated soils. However, fate, behaviour and bioavailability of different Sb compounds in soils are insufficiently known. Therefore, in this present study, the effects of soil properties and ageing on bioavailability of four different Sb compounds (C₈H₄K₂O₁₂Sb₂, Sb₂S₃, Sb₂O₃ and Sb₂O₃ nanoparticles) were evaluated during 120 days ageing time. A black soil (BS) with approximately 12% organic matter (OM) and a red soil (RS) with less than 1% OM were amended with 1000 mg Sb kg^-1 of different Sb compounds and subjected to single extractions with distilled (DI) water, 2M HNO₃, Simplified Bioaccessibility Extraction Test (SBET) and a modified Community Bureau of Reference (BCR) sequential extraction method. The results revealed that there are substantial variations in dissolution rate of various Sb sources, depending upon soil type and Sb compound. The amounts of DI water extractability of Sb during the incubation time varied between <1% and 2%, whereas HNO₃ extractable fractions and Sb bioaccessibility at the end of ageing time ranged between about 1%-3% and <1%-9% of the total Sb, with maximum bioaccessibility observed in BS contaminated with C₈H₄K₂O₁₂Sb₂. The residual and labile fractions accounted for 77-93% and 0.1-4% of the total Sb, respectively, indicating that Sb is mostly associated with recalcitrant fractions of the soils. The results of single and sequential extraction studies revealed that source of Sb, ageing time and soil properties can greatly affect the bioavailability of Sb in soils. The findings of this research provide a deeper understanding of the potential risks associated with Sb compounds and highlights the role of site-specific considerations for improving the robustness of toxicity guidelines and long-term management of Sb contaminated sites.

The influence of association of plant growth-promoting rhizobacteria and zero-valent iron nanoparticles on removal of antimony from soil by Trifolium repens

Using association of plants, nanomaterials, and plant growth-promoting bacteria (PGPR) is a novel approach in remediation of heavy metal-contaminated soils. Co-application of nanoscale zerovalent iron (nZVI) and PGPR to promote phytoremediation of Sb-contaminated soil was investigated in this study. Seedlings of Trifolium repens were exposed to different regimes of nZVI (0, 150, 300, 500, and 1000 mg/kg) and the PGPR, separately and in combination, to investigate the effects on plant growth, Sb uptake, and accumulation and physiological response of the plant in contaminated soil. Co-application of nZVI and PGPR had positive effects on plant establishment and growth in contaminated soil. Greater accumulation of Sb in the shoots compared to the roots of T. repens was observed in all treatments. Using nZVI significantly increased accumulation capacity of T. repens for Sb with the greatest accumulation capacity of 3896.4 μg per pot gained in the "PGPR+500 mg/kg nZVI" treatment. Adverse impacts of using 1000 mg/kg nZVI were found on plant growth and phytoremediation performance. Significant beneficial effect of integrated use of nZVI and PGPR on plant photosynthesis was detected. Co-application of nZVI and PGPR could reduce the required amounts of nZVI for successful phytoremediation of metalloid polluted soils. Intelligent uses of plants in accompany with nanomaterials and PGPR have great application prospects in removal of antimony from soil.

Ecological and Human Health Risks of Heavy Metals in Shooting Range Soils: A Meta Assessment from China

Contamination of shooting ranges by heavy metals in particular Pb represents a widespread environmental issue attracting concern worldwide. Contaminant accumulation in shooting range soils can pose potential ecological risks and health risks for shooters and workers. Based on the published data on metal contamination at five shooting ranges in China, potential ecological and human health risks of several metals, and in particular, Pb were assessed for the five surveyed shooting ranges. Data show the mean concentrations of Pb, Cu, Hg, Sb, Ni and Cr in various ranges were all higher than the local soil background values, implying their accumulation was induced by shooting activities. The degree of contamination varied with sites and metals, very high Pb contamination at Range 1, Range 2 and Range 5-1, while moderate Pb contamination at Range 3 and Range 5-2. Comparatively, As, Zn and Co showed no contamination. Among the surveyed metals, Pb, Cu, Hg and Sb in shooting range soils displayed relatively high potential ecological risks. The overall degree of potential ecological risk was very high at Range 1 and Range 2, considerable at Range 4 and Range 5-1, and low at Range 3 and Range 5-2. The mean HI (hazard index) of Pb at Range 2 and the maximum HI values at Range 1 and Range 4 were higher than 1, suggesting a possibility of non-carcinogenic risks of Pb contamination at these sites. However, Pb in other range soils and other metals, across the five ranges, all exhibited no non-carcinogenic risks. The cancer risks of the four carcinogenic contaminants (As, Co, Cr, and Ni) were acceptable or negligible at all ranges. In conclusion, contamination of Pb and other metals such as Cu, Hg and Sb can cause various potential ecological risks at all the surveyed ranges, but only Pb at three ranges shows possible health risks. Contamination of Pb in the surveyed shooting ranges should be managed to reduce its possible environmental and health risks.

Environmental risk related to presence and mobility of As, Cd and Tl in soils in the vicinity of a metallurgical plant - Long-term observations

Analysis of the content of As, Cd and Tl accompanying Zn-Pb ores was performed using soil material sampled around the zinc-works in Miasteczko Śląskie. It was found that the total content of As, Cd and Tl was considerably higher than the values recorded at the same sites 20 years earlier. This clearly confirms considerable pollution of the environment which continues despite pro-ecological actions taken by the zinc-works. The analysis of the spatial distribution of pollution revealed that the zinc-works itself is no longer the main source of contamination as was the case in 1998. Instead, in 2018 the main sources of As, Cd and Tl emissions were the erosion and deflation processes in old, unprotected mining and industrial waste dumps located near the zinc-works. The most polluted soil layers are the top layers in the soil profile. The content of As, Cd and Tl determined in them was 10 times greater than in the deep layers. There was also a positive change in environmental conditions, which occurred over the preceding 20 years, namely an increase in the content of sparingly soluble fractions, fractions bound with organic matter, and residual fractions. It was also found that depending on the geochemical background and readily mobile fraction values used in the calculations, there is still very high contamination and very high ecological risk with respect to As, Cd and Tl after 20 years. However, when using the quantity of phytoavailable elements as well as the quantity of cations on ion exchange positions and bound to carbonates to calculate the risk assessment code, the analysis showed that environmental conditions improved.

Scoping review of the impacts of urban agriculture on the determinants of health

Background

There has been an increasing interest in urban agriculture (UA) practice and research in recent years. Scholars have already reported numerous beneficial and potential adverse impacts of UA on health-related outcomes. This scoping review aims to explore these impacts and identify knowledge gaps for future UA studies.

Methods

A systematic search was conducted in seven electronic bibliographic databases to identify relevant peer-reviewed studies. Articles were screened and assessed for eligibility. From eligible studies, data were extracted to summarize, collate, appraise the quality and make a narrative account of the findings.

Results

A total of 101 articles (51 quantitative, 29 qualitative, and 21 mixed methods studies) were included in our final analysis. Among these articles, 38 and 37% reported findings from North America and Sub-Saharan Africa respectively. Quantitative studies revealed evidence of positive impacts of UA on food security, nutrition outcomes, physical and mental health outcomes, and social capital. The qualitative studies reported a wide range of perceived benefits and motivations of UA. The most frequently reported benefits include contributions to social capital, food security, health and/or wellbeing. However, the evidence must be interpreted with caution since the quality of most of the studies was assessed as weak to moderate. While no definitive conclusions can be drawn about the adverse impacts of UA on health, paying particular attention to contamination of UA soil is recommended.

Conclusion

More peer-reviewed studies are needed in areas where UA is practiced such as Latin America and Caribbean. The inconsistency and the lack of strong quality in the methodology of the included studies are proof that more rigorous studies are also needed in future research. Nevertheless, the substantial existing evidence from this review corroborate that UA can influence different determinants of health such as food security, social capital, health and well-being in a variety of contexts.

Electronic supplementary material

The online version of this article (10.1186/s12889-019-6885-z) contains supplementary material, which is available to authorized users.