Methodological evaluation of method for dietary heavy metal intake

The toxicological analysis and safety assessment of heavy metals (Hg, Pb, Cd, and As) in food for special medical purposes (FSMP) available in Polish pharmacies for oncological patients

The presence of heavy metals in food products may seem an archaic concern; however, our study reveals that the risk is significant, unexpectedly in Food for Special Medical Purposes (FSMP) for oncology patients available in Polish pharmacies. This investigation fills that gap through a detailed toxicological analysis and health risk assessment of these heavy metals in FSMP products (n = 23) using inductively coupled plasma mass spectrometry (ICP-MS). Our comprehensive risk assessment involved evaluating (1) the concentrations of As, Cd, Hg, and Pb in both liquid and powdered FSMP formulations, (2) the amount of heavy metals ingested per serving as specified by the manufacturer, and (3) the cumulative daily and weekly intake adjusted for body weight, benchmarked against the provisional tolerable weekly intake (PTWI). While most samples were below PTWI limits, Cd levels raised concerns due to potential cumulative exposure risks, particularly for oncology patients consuming these products regularly. This study underscores the hidden dangers of heavy metal contamination in FSMP, emphasizing the need for vigilant monitoring and stringent regulatory frameworks to ensure patient safety. By uncovering these latent risks through meticulous toxicological assessment, our research provides crucial insights that could safeguard vulnerable populations. This study is significant due to concerns related to the complex risk assessment of FSMP for cancer patients, considering the complexity of oncological diseases and other comorbid factors, as well as the verification of available legal and regulatory acts of FSMP at the European Community level.

Vermi-remediation impacts on growth and metals bioaccumulation in tomato irrigated with wastewater

Due to their persistence in the environment, and their highly toxic and bioaccumulative nature, heavy metals are well known to the environment. Vermicompost has gained popularity because it improves soil properties and, most importantly, remediates and immobilizes heavy metals. The present study assessed vermicompost effects on heavy metal bioaccumulation in tomato plants irrigated with wastewater. A plastic bag experiment was carried out with 5 kg of growing media in each bag. Growing media contain garden soil with four levels of vermicompost mixed at 0%, 5%, 15%, and 25%. The pots were irrigated with wastewater from different industries and tap water, which was taken as control. Wastewater was collected from the pharmaceutical industry, plastic industry, and sewage water of Hayatabad Industrial Estate, Peshawar. Vermicompost application significantly affected all tomatoes' growth attributes and heavy metals concentration. Results revealed that minimum Cd (2.48 mg kg-1), Cr (1.27 mg kg-1), Cu (4.10 mg kg-1), and Pb (0.62 mg kg-1) concentrations were recorded in tomatoes cultivated in 25 % vermicompost amended soil, while, maximum Cd (5.23 mg kg-1), Cr (2.29 mg kg-1), Cu (8.84 mg kg-1) and Pb (2.18 mg kg-1) concentrations were reported in sewage water irrigated plants., Overall, vermicompost applied at 25% significantly enhanced plant growth and yield, reducing the bioavailability and bioaccumulation of heavy metals. From the finding of this study, it is observed that wastewater irrigation of plants should be avoided because of the high level of heavy metals; in contrast, the application of vermicompost is highly recommended as compost reduces heavy metals bioaccumulation and enhances productivity.

Lead stabilization and remediation strategy with soil amendment in situ immobilization in contaminated range lands

In situ immobilization is a potential approach that can be used to remediate low-to-medium levels of heavy-metal in contaminated-soil. There is little known about how modifications to soil characteristics may affect Pb's release from soil. The four different amendments, triple-superphosphate and attapulgite were combined in Ad-1; zeolite and triple-superphosphate were in Ad-2; hydroxyapatite and humus were in Ad-3; and nano-carbon. These amendments are mostly made of phyllosilicate minerals, humus, base minerals, and nano-carbon, respectively. Results revealed that the test amendments' maximal Pb-adsorption capacity varied from 7.47 to 17.67 mg g-1. Surface precipitation and ion-exchange were found to be the main mechanisms for Pb-adsorption by Ad-1 and Ad-2, while Ad-3 and Ad-4 were promising among the all, according to analysis of the modifications both before and after Pb loading. When the pH dropped (7-1) or the ion-strength rose (0-0.2 M), there was a discernible rise in the Pb-desorption percentages from the amendments. It was determined that Ad-3 and Ad-4 were more effective in situ immobilizing lead in contaminated-soils because of their high adsorption capacities (12.82 and 17.67 mg g-1) and low-desorption percentages (4.46-6.23%) at ion-strengths of 0.01-0.1 mol L-1 and pH levels ranging from 5 to 7.

Transformation of heavy metals from contaminated water to soil, fodder and animals

A serious environmental problem that threatens soil quality, agricultural productivity, and food safety is heavy metal pollution in water sources. Heavy metal pollution is the main problem in tehsil Pasrur, Sialkot, Pakistan. Present study was arranged to notice the heavy metals in water, soil, forages and buffalo milk. There are seven sites that were used for this experiment. Highest malondialdehyde (MDA) contents (3.00 ± 0.01) were noticed in barseem roots at site 7. Ascorbate Peroxidase (APX) was reached at its peak (1.93 ± 0.01) at site 7 in the fresh barseem. Maximum protein contents (0.36 ± 0.01) were observed in fresh plant samples at site 2. Site 3's buffalo milk samples had the highest Ni content (7.22 ± 0.33 ppm), while Site 3's soil samples had the lowest Cr content (8.89 ± 0.56 ppm), Site 1's plant shoots had the lowest Cr content (27.75 ± 1.98 ppm), and Site 3's water had the highest Cr content (40.07 ± 0.49 ppm). The maximum fat content (5.38 ± 2.32%) was found in the milk of the animals at site 7. The highest density (31.88 ± 6.501%), protein content (3.64 ± 0.33%), lactose content (5.54 ± 0.320%), salt content (0.66 ± 0.1673%), and freezing point (- 0.5814 ± 0.1827 °C) were also observed in the milk from animals at site 7, whereas site 5 displayed the highest water content (0.66 ± 0.1673%) and peak pH value (11.64 ± 0.09). In selected samples, the pollution load index for Ni (which ranged from 0.01 to 1.03 mg/kg) was greater than 1. Site 7 has the highest conductivity value (5.48 ± 0.48). Values for the health risk index varied from 0.000151 to 1.00010 mg/kg, suggesting that eating tainted animal feed may pose health concerns. Significant health concerns arise from metal deposition in the food chain from soil to feed, with nickel having the highest health risk index.

Bio-sorption capacity of cadmium and zinc by Pseudomonas monteilii with heavy-metal resistance isolated from the compost of pig manure

The tolerance of Pseudomonas monteilii X1, isolated from pig manure compost, to Cd and Zn, as well as its capacity for biosorption, were investigated. The minimum inhibitory concentrations (MIC) of Cd and Zn for the strain were 550 mg/L and 800 mg/L, respectively. Untargeted metabolomics analysis revealed that organic acids and derivatives, lipids and lipid-like molecules, and organic heterocyclic compounds were the main metabolites. The glyoxylate and dicarboxylate metabolism pathway were significantly enriched under Cd2+ stress. The isothermal adsorption and adsorption kinetics experiments determined that the strain had adsorption capacities of 9.96 mg/g for Cd2+ and 23.4 mg/g for Zn2+. Active groups, such as hydroxyl, carboxyl, and amino groups on the cell surface, were found to participate in metal adsorption. The strain was able to convert Zn2+ into Zn3(PO4)2·4H2O crystal. Overall, this study suggested that Pseudomonas monteilii has potential as a remediation material for heavy metals.

Pollution indices of selected metals in tea (Camellia sinensis L.) growing soils of the Upper Assam region divulge a non-trifling menace of National Highway

The study investigated the influence of a National Highway (NH) traversing tea estates (TEs) on heavy metal (HM) contamination in the top soils of Upper Assam, India. The dispersion and accumulation of six HMs, viz. cadmium (Cd), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), and zinc (Zn), within tea-growing soils were assessed using diverse indices: contamination factor (CF), degree of contamination (DC), enrichment factor (EF), geo-accumulation index (Igeo), modified degree of contamination (MDC), Nemerow pollution index (PINemerow), pollution load index (PLI), potential ecological risk factor (Eri), and potential ecological risk index (RI). The order of HM prevalence was Fe > Mn > Zn > Ni > Cu > Cd. Elevated Cd levels near the NH prompted immediate attention, while Cd and Zn showed moderate pollution in CF, EF, and RI. The remaining metals posed minimal individual risk (Eri< 40), resulting in an overall contamination range of "nil to shallow," signifying slight contamination from the studied metals. From MDC values for investigated metals, it was found to be "zero to very low degree of contamination" at all locations except the vicinity of NH. Soil pollution, as determined by PLI, indicated unpolluted soils in both districts, yet PINemerow values indicated slight pollution. The statistical analysis revealed that there is a significant decrease in most of the indices of HM as the distance from NH increases. The application of multivariate statistical techniques namely Principal Component Analysis and Cluster Analysis showed the presence of three distinct homogenous groups of distances based on different indices. This investigation underscores NH-associated anthropogenic effects on TE soil quality due to HM deposition, warranting proactive mitigation measures.

Foliar application of plant growth regulators for enhancing heavy metal phytoextraction efficiency by Sedum alfredii Hance in contaminated soils: Lab to field experiments

The phytoremediation efficiency of plants in removing the heavy metals (HMs) might be influenced by their growth status and accumulation capacity of plants. Herein, we conducted a lab-scale experiment and a field try out to assess the optimal plant growth regulators (PGRs) including indole-3-acetic acid (IAA)/brassinolide (BR)/abscisic acid (ABA) in improving the phytoextraction potential of Sedum alfredii Hance (S. alfredii). The results of pot experiment revealed that application of IAA at 0.2 mg/L, BR at 0.4 mg/L, and ABA at 0.2 mg/L demonstrated notable potential as optimal dosage for Cd/Pb/Zn phytoextraction in S. alfredii. The findings of subcellular level of Cd/Pb/Zn in leaves showed that IAA (0.2 mg/L), BR (0.4 mg/L) or ABA (0.2 mg/L) promoted the HMs storage in the soluble and cell wall fraction, therefore contributing HMs subcellular compartmentation. In addition, application of PGRs notably enhanced the antioxidant system (SOD, CAT, POD, APX activities) while reducing lipid peroxidation (MDA content) in S. alfredii, consequently improving HMs tolerance and growth of S. alfredii. Moreover, the results of field trial showed that application of BR, IAA, or ABA+BR substantially improved the growth of S. alfredii by inducing plants biomass and augmenting the levels of photosynthetic pigment contents. Notably, ABA+BR noticed the highest theoretical biomass by 42.9 %, followed by IAA (41.6 %), and BR (36.4 %), as compared with CK. Additionally, ABA+BR treatment showed effectiveness in removing the Cd by 103.4 %, while BR and IAA led to a significant increase of Pb and Zn removal by 239 % and 116 %, respectively, when compared with CK. Overall, the results of this study highlights that the foliar application of IAA, BR, or ABA+BR can serve as viable strategy to boosting phytoremediation efficiency of S. alfredii in contaminated soil by improving the biomass and metal accumulation in harvestable parts.

Thallium uptake and risk in vegetables grown in pyrite past-mining contaminated soil amended with organic fertilizer (compost): A potential method for Tl contamination remediation

Thallium (Tl) is a highly toxic trace metal that can cause severe pollution and damage to the ecological system. In this study, a field trial was conducted in a Tl-rich pyrite-barite past-mining area to unveil the fate of Tl in agricultural practice. Tuscany kale and red chicory cultivated in soil impacted by the dismissed mine of Valdicastello Carducci (Northern Tuscany, Italy) displayed significantly different uptake behaviors of Tl. Hyper-accumulation of Tl was observed in kale leaves and its content reached up to 17.1 mg kg-1 whereas only <0.70 mg kg-1 of Tl was found in leaves of red chicory. Due to the regionally polymetallic pollution, Tuscany kale grown in this area possessed a great Tl intake risk for the residents. As for the fertilization treatment, Tl in Tuscany kale leaves fertilized with mineral fertilizer (NPK) and compost were 21.4 and 12.8 mg kg-1. The results suggested a potential remediation ability of compost in diminishing Tl in the vegetable leaves and thus may reduce its risk in the soil-crop system. Since Tl poisoning emergency may occur in agricultural fields near past-mining zones, it is critical to establish possible remediation measures to ensure food safety surrounding former mining areas likewise.

Removal of toxic metals using iron sulfide particles: A brief overview of modifications and mechanisms

Growing mechanization has released higher concentrations of toxic metals in water and sediment, which is a critical concern for the environment and human health. Recent studies show that naturally occurring and synthetic iron sulfide particles are efficient at removing these hazardous pollutants. This review seeks to provide a concise summary of the evolution in the production of iron sulfide particles, specifically nanoparticles, through the years. This review presents an outline of the synthesis process for the most dominant forms of iron sulfide: mackinawite (FeS), pyrite (FeS2), pyrrhotite (Fe1-x S), and greigite (Fe3S4). The review confirms that both natural forms of iron sulfide and modified forms of iron sulfide are highly effective at removing different heavy metals and metalloids from water. Concurrently, this review reveals the interaction mechanism between toxic metals and iron sulfide, along with the impact of conditions for remedy and rectification. None the less, modifications and future investigations into the synthesis of novel iron sulfides, their use to adsorb diverse environmental pollutants, and their fate after injection into polluted aquifers, remain crucial to maximizing pollution control.

Biohybrid Adsorbent for the Preconcentration of Lead and Its Determination in Fruit Juices by Electrothermal Atomic Absorption Spectrometry

BACKGROUND

Fruit juices are one of the most non-alcoholic beverages consumed in the world. Essential elements and other nutrients present in fruit juices play an important role in human well-being. However, fruit juices may also contain potentially toxic elements at trace levels, causing health risks.

OBJECTIVE

The objective of this work was to develop an analytical methodology based on the preconcentration of lead using a new biodegradable hybrid material (BHM) composed of Rhodococcus erythropolis AW3 bacteria and Brassica napus hairy roots.

METHODS

The BHM was implemented in an online solid-phase extraction (SPE) system for the determination of lead in fruit juices by electrothermal atomic absorption spectrometry (ETAAS).

RESULTS

Effects of critical parameters on lead retention were studied. Under optimal experimental conditions, extraction efficiency higher than 99.9% and an enrichment factor of 62.5 were achieved. The dynamic capacity of the BHM was 36 mg/g, which favored the reuse of the column for at least eight biosorption-desorption cycles. The LOD and LOQ for preconcentration of 5 mL of sample were 5.0 and 16.5 ng/L lead, respectively. The RSD was 4.8% (at 1 µg/L lead and n = 10).

CONCLUSION

The developed method was suitable for application to lead determination in different types of fruit juice.

HIGHLIGHTS

A novel microextraction procedure based on the use of a biohybrid adsorbent. Highly sensitive determination of Pb at trace levels. Analysis of Pb in fruit juices samples. An eco-friendly microextraction technique for Pb determination.

The effects of soil intake on the growth performance, rumen microbial community and tissue mineral deposition of German Mutton Merino sheep

Soil ingestion by livestock is common in grazing ecosystems, but few studies have been conducted to assess its effect on the animal organism. The topic is worthy of attention because these potential effects are likely to be enriched in the food chain and interfere with animal and human health. In this study, we present an indoor feeding trial conducted based on a completely randomized design to comprehensively evaluate the effects of simulated soil ingestion during grazing on nutrient digestibility, rumen fermentation, and microflora, and mineral deposition in the organs and tissues of sheep. Eighteen Mutton Merino crossbred sheep (42.7 ± 2.34 kg) were randomly allotted to three treatments and fed diets containing 0% (Control), 5% (SOIL5), and 10% (SOIL10) for 62 d, including a 7-d metabolism trial. It was found that soil intake altered the rumen fermentation in sheep, as evidenced by a decrease in total volatile fatty acids (VFA) and acetate concentrations in rumen fluid of 50.6% and 51.3%, respectively (p < 0.01), with soil proportion in the diet increased from 0% to 10%. Soil ingestion also reduced the species richness of rumen bacteria, with the relative abundance of Bacteroidetes decreasing significantly (p < 0.01), while that of Firmicutes and Proteobacteria increased considerably (p < 0.05). In terms of mineral elements deposition, higher levels of iron (Fe) were detected in the spleen and liver, and a higher concentration of copper (Cu) and zinc (Zn) in the liver were found in sheep fed a diet containing 5% soil compared to the other two groups (p < 0.05). Moreover, the concentrations of lead (Pb) in the liver and kidney, and arsenic (As) in the heart were also clearly increased after ingestion of soil (p < 0.05). Our findings indicate that although soil intake had no significant effect on the growth performance of sheep, it altered ruminal fermentation and increased the risk of excessive Fe, Pb, and As in their organism. This study supplies a theoretical basis for risk assessment of soil ingestion in grazing livestock.

Current Status and Health Risk Assessment of Heavy Metals Contamination in Tea across China

Tea is a non-alcoholic beverage popular among Chinese people. However, due to the application of chemical and organic fertilizers in the tea planting process, the environment pollutionaround the tea plantation, and the instruments used in the processing, heavy metal elements will accumulate in the tea, which brings health risks for tea consumers. This study summarized heavy metal concentrations from 227 published papers and investigated the current contamination status of tea and tea plantation soils, and, finally, the risk of heavy metal exposure to tea consumers in China is assessed, in terms of both non-carcinogenic and carcinogenic risk. The average contamination of six heavy metals in tea-arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), and lead (Pb)-were 0.21, 0.14, 1.17, 14.6, 0.04, and 1.09 mg/kg, respectively. The areas with high concentrations of heavy metals in tea were concentrated primarily in southwest China, some areas in eastern China, and Shaanxi Province in northwest China. The non-carcinogenic risks of heavy metals in tea are all within safe limits. The national average HI value was 0.04, with the highest HI value of 0.18 in Tibet, which has the largest tea consumption in China. However, the carcinogenic risks of Cd in Shaanxi Province, Anhui Province, and southwest China exceed the acceptable range, and due attention should be given to these areas.

Technical guidelines for risk assessment of heavy metals in traditional Chinese medicines

BACKGROUND

Heavy metals are considered a global concern because they can deteriorate human health. This guideline aims to scientifically evaluate health risk of heavy metals in TCM and to propose a reference for decision making in developing TCM-related health policies.

METHODS

Using a multidisciplinary approach, a steering committee oversaw the development of the guideline. To obtain a reasonable and accurate risk assessment, key exposure assessment parameters for TCM, e.g., exposure frequency (EF), exposure duration (ED), and daily ingestion rate (IR) were obtained from surveys. In addition, transfer rates for heavy metals from Chinese medicinal materials (CMM) to decoctions or preparations were examined.

RESULTS

Based on the scientific theory of risk control, the guideline was designed systematically, and principles and procedures for the risk assessment of heavy metals in TCM were identified. The guideline can be utilized to assess the risk of heavy metals in CMM and Chinese patent medicines (CPM).

CONCLUSION

This guideline may help standardize the risk assessment of heavy metals in TCM, advance regulatory standards for heavy metals in TCM, and ultimately improve human health through scientific TCM usage in clinic.

Extraction of heavy metals by cooking/preserving of seafood, tuna and poultry from Romania - A source of contamination with heavy metals

The study aims to provide evidence regarding the impact of the extraction of heavy metals into food products through conventional cooking and preserving of foods like seafood, tuna, and poultry. The optical emission spectrometric technique with an inductively coupled plasma source (ICP-OES) was employed to determine trace levels of heavy metals in the muscle tissue of seafood, fish meat, tuna species, poultry, and turkey that was collected raw, cooked, frozen, and preserved. Conventional cooking increased the concentration of some heavy metals (Al, Sn, Fe, Co, Ti, and Mn) by more than 100.00%, while preserving the mussels promoted the extraction and accumulation of metals such as Al, Fe, Sn, Zn, Cu, Hg, and As, resulting in an increase in concentration of more than 180.00%.

The screening method for use of wild pheasant feathers in the monitoring of environmental pollution with heavy metals

It has been shown that some species of birds, especially herbivorous and territorial ones, are more sensitive to the effects of toxic substances compared to mammals. This allows for taking integrated actions in the area of environmental protection and monitoring in a holistic sense (at various trophic levels). Therefore, this study aimed to assess the possibility of using pheasant feathers (Phasianus colchicus) as a potential bioindicator ofenvironmental contamination, and thus to determine the concentration of heavy metals (lead-Pb, arsenic-As, cadmium-Cd, chromium-Cr, nickel-Ni, and zinc-Zn) in the analyzed tissue of animals inhabiting the forest districts of the Lubartów, Tomaszów, Skierniewice, and Ostrowiec Świętokrzyski areas. The chemical analysis used to determine the concentration of toxic elements in pheasant feathers was carried out by inductively coupled plasma mass spectrometry. The highest concentrations of Cr and Zn were found in birds from the Lubartów Forest District (1.93 mg/kg and 120.63 mg/kg, respectively), As and Ni in the Tomaszów Forest District (0.55 mg/kg and 1.60 mg/kg, respectively), Cd in the Lubartów Forest District and Skierniewice (0.04 mg/kg), and Pb in the Skierniewice Forest Distict (6.79 mg/kg). The observed results were strongly related to soil contamination and urbanization index, as key environmental factors which significantly determine the metal content in pheasant feathers. Therefore, proposed non-invasive measurements of the elemental composition of feathers of birds living in specific areas may be an important indicator of environmental pollution in relation to the high impact of anthropopressure.

Contamination characteristics and source analysis of potentially toxic elements in dustfall-soil-crop systems near non-ferrous mining areas of Yunnan, southwestern China

Potentially toxic elements (PTEs) in the dustfall-soil-crop system pose a serious threat to the ecological environment and agricultural production. However, there is still a knowledge gap in terms of better understanding the distinctive sources of PTEs by integrating various models and technologies. In this study, we comprehensively investigated the concentrations, distribution, and sources of seven PTEs in a dustfall-soil-crop system (424 samples in total) near a typical non-ferrous mining area, using absolute principal component score/multiple linear regression (APCS/MLR) combined with X-ray diffraction (XRD) and microscopy techniques. Our results showed that the mean values of As, Cd, Cr, Cu, Ni, Pb, and Zn in the soils were 211, 14, 105, 91, 65, 232, and 325 mg/kg, respectively. These values were significantly higher than the background soil values in Yunnan. Except for Ni and Cr, all elements in the soil were significantly higher than the screening values of agricultural lands in China. The spatial distribution of PTE concentrations was similar among the three media. The ACPS/MLR, XRD, and microscopy analyses further indicated that soil PTEs mainly originated from industrial activities (37 %), vehicle emissions and agricultural activities (29 %), respectively. Dustfall PTEs mainly originated from vehicle emissions and industrial activities, accounting for 40 % and 37 %, respectively. Crop PTEs mainly originated from vehicle emissions and soil (57 %), and agricultural activities (11 %), respectively. PTEs seriously threaten the safety of agricultural products and the ecological environment once they settle from the atmosphere to soil and crop leaves, further accumulate in crops, and spread through the food chain. Therefore, our study provides scientific evidence for government regulators to control PTE pollution and reduce their environmental risks in dustfall-soil-crop systems.

Risk Assessment of Heavy Metals in Soils from Four Different Industrial Plants in a Medium-Sized City in North China

Laboratory experiments were carried out to analyze 39 soil samples collected from four industrial areas in Xuzhou City using inductively coupled plasma mass spectrometry and atomic fluorescence spectrometry. The descriptive statistics of heavy metals (HMs) in the soil profiles showed that the HM content at three depths was highly variable, and most coefficients of variation (CVs) showed moderate variability. The enrichment of Cd at all depths exceeded the risk screening value, and Cd pollution occurred in four plants. The enrichment of the other HMs at three depths was mainly concentrated in the pharmaceutical plant A and chemical plant C. It was found that the different HMs had different vertical distribution characteristics. For the different industrial plants, the raw materials and products not only made the spatial distribution characteristics of the HMs different, but also caused the HM types and contents to differ. The average single pollution indices of Cd in plant A, iron-steel plant B, and plant C indicated a slight pollution level. The other seven HMs in A, B, and C and all HMs in chemical plant D belonged to the safe category. The mean values of the Nemerow pollution index in the four industrial plants belonged to the warning category. The analysis showed that none of the HMs posed potential noncarcinogenic health risks, and only the carcinogenic health risks of Cr in plants A and C were unacceptable. The carcinogenic effect of Cr through the inhalation intake of resuspended soil particulates and that of Cd, Ni, and As via direct oral ingestion were the main exposure pathways.

Exogenous silicon promotes cadmium (Cd) accumulation in Sedum alfredii Hance by enhancing Cd uptake and alleviating Cd toxicity

Soil Cadmium (Cd) pollution has become a serious environmental problem. Silicon (Si) plays key roles in alleviating Cd toxicity in plants. However, the effects of Si on mitigation of Cd toxicity and accumulation of Cd by hyperaccumulators are largely unknown. This study was conducted to investigate the effect of Si on Cd accumulation and the physiological characteristics of Cd hyperaccumulator Sedum alfredii Hance under Cd stress. Results showed that, exogenous Si application promoted the biomass, Cd translocation and concentration of S. alfredii, with an increased rate of 21.74-52.17% for shoot biomass, and 412.39-621.00% for Cd accumulation. Moreover, Si alleviated Cd toxicity by: (i) increasing chlorophyll contents, (ii) improving antioxidant enzymes, (iii) enhancing cell wall components (lignin, cellulose, hemicellulose and pectin), (iv) raising the secretion of organic acids (oxalic acid, tartaric acid and L-malic acid). The RT-PCR analysis of genes that involved in Cd detoxification showed that the expression of SaNramp3, SaNramp6, SaHMA2 and SaHMA4 in roots were significantly decreased by 11.46-28.23%, 6.61-65.19%, 38.47-80.87%, 44.80-69.85% and 33.96-71.70% in the Si treatments, while Si significantly increased the expression of SaCAD. This study expanded understanding on the role of Si in phytoextraction and provided a feasible strategy for assisting phytoextraction Cd by S. alfredii. In summary, Si facilitated the Cd phytoextraction of S. alfredii by promoting plant growth and enhancing the resistance of plants to Cd.

Source apportionment and risk assessment of soil heavy metals around a key drinking water source area in northern China: multivariate statistical analysis approach

With the intensive urbanization and industrialization in recent years, lots of products containing heavy metals (HMs) have brought in severe environment problems. Yuqiao Reservoir (YQR) is an important drinking water source area in Tianjin of China, and the soil environmental quality of YQR is vital for human health. The goal of this study was to identify the priority control pollutants and hotspots of HMs contamination of YQR catchment. Thus, an integrated field investigation was conducted to analyze the major elements such as As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in soils around YQR. Geoaccumulation index (Igeo), enrichment factor (EF) and potential ecological risk index (PERI) were employed to assess the contamination status of HMs. The average contents of these elements were given as follows: As 7.97 mg/kg, Cd 0.31 mg/kg, Cr 86.1 mg/kg, Cu 24.7 mg/kg, Hg 0.044 mg/kg, Ni 30.7 mg/kg, Pb 27.3 mg/kg and Zn 76.7 mg/kg. According to geoaccumulation index (I_geo) and enrichment factor (EF) values, Cd, Cr, Pb and As showed a prominent enrichment. The result of multivariate statistics showed that Cd, Cr, Cu, As, Ni, Pb and Zn concentrations were mainly affected by human activities, whereas Hg was mainly from natural release. The anthropogenic activities were the major sources with a contribution of 91.46%, while natural origins only contributed 8.54%. And agricultural fertilization, mining and traffic activities are the most probable sources of these heavy metals in the soil. The PERI values indicated that 65.7% of total HMs were at low risk, 22.5% in moderate risk and 11.8% in considerable risk. To ensure soil environmental quality and human health, cadmium should be listed as a priority control pollutant. Spatial maps of HMs and their integrated PERI provided clear hotspots that indicated lower risk in the region close to YQR but higher risk in the region far from YQR.

Novel Platinum-Nickel Composite Trap for Simultaneous and Direct Determination of Mercury and Cadmium in Soil and Its Mechanism Study

In this work, following a metal-ceramic heater (MCH) as an electrothermal vaporizer (ETV), a novel composite Pt/Ni trap based on platinizing the foamed nickel was first fabricated to trap Hg and Cd simultaneously. So, a solid sampling Hg-Cd analyzer was developed to simultaneously detect trace Hg and Cd in soil samples, mainly consisting of an MCH, a composite Pt/Ni trap, and an atomic fluorescence spectrometer (AFS). This small-size MCH-ETV system only consumes 100 W for the complete vaporization of Hg and Cd in soil matrices. The Pt/Ni trap fulfills the complete trapping of Hg and Cd following the solid sampling MCH-ETV system and then fast releases them by heating. It was proved that trapped and released Hg and Cd by the Pt/Ni trap are atomic species using X-ray photoelectron spectroscopy (XPS) and other approaches; specially, the effective cotrapping of Hg and Cd might be due to forming alloys of Hg + Pt and Cd + Ni on the Pt/Ni trap. Under the optimized conditions, the method detection limits (LODs) of Hg and Cd reached 0.4 μg/kg and 0.04 μg/kg for a 20 mg sample size, the relative standard deviations (RSDs) were within 12% and 8% for soil samples, respectively, and the recoveries ranged from 96% to 105%, indicating favorable analytical sensitivity, precision, and accuracy. The whole analysis time can be controlled within 5 min without the soil digestion process. The proposed Hg-Cd analyzer is thus suitable for rapid detection of Hg and Cd in soil samples with advantages such as simplicity, green, and safety. Further, the proposed solid sampling ETV-composite trap method has a promising application potential in the field and rapid detection for multielements.

Pollution, sources, and human health risk assessment of heavy metals in urban areas around industrialization and urbanization-Northwest China

Heavy metal pollution in urban soils and dust is mostly caused by extensive anthropogenic activity during urbanization and industrialization. In this research study, the pollution characteristics, sources, ecological and human health risks of heavy metals in urban soil, and dust have been thoroughly evaluated. The research findings demonstrate that dust has a higher level of contamination than urban soil, such as Pb, Cu, and Zn metals are more contaminated in both urban soil and dust throughout the city, and Hg and As are also found in locations with a high concentration of heavy industrial companies. This implies that traffic emissions are still a significant source of metals in urban areas, though industrial companies also contribute. The health risk assessment model used to calculate human exposure revealed that the non-carcinogenic and carcinogenic risks of selected metals in soil and dust were generally in the low range, except for the carcinogenic risk from Cr in children. Statistical analysis revealed that Cr and Ni concentrations were mainly of natural origin, Cu and Zn have been sourced from traffic, whereas Pb, Hg, and As have been sourced from industrial activities. The overall recommendation is that the road traffic environment and municipal construction facilities need to be improved to ensure the sustainable development of the city's environment, while pollution from industrial waste is strongly controlled.

Determination of heavy metals contamination in thyme products by inductively coupled plasma mass spectrometry

Thyme herbs constitute a major part of the Mediterranean diet and are gaining worldwide popularity. However, their chemical contamination with toxic metals may put consumers at a health risk. The objective of this study was to assess the incidence of Arsenic (As), Cadmium (Cd), Lead (Pb) and Mercury (Hg) in thyme-containing products. Composite samples were collected twice at six-month interval. Samples were digested by microwave digestion oven and analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). 11%, 22%, and 86% of samples had unacceptable levels of As, Hg and Pb respectively according to the international standards set by Codex Alimentarius and all the samples had acceptable limits of Cd. This study highlighted the importance of monitoring and enforcing regulatory actions related to the contamination of the food chain with heavy metals.

Mechanisms of Cd-induced Cytotoxicity in Normal Human Skin Keratinocytes: Implication for Human Health

Cadmium (Cd) is one of the toxic heavy metals found widely in the environment. Skin is an important target organ of Cd exposure. However, the adverse effects of Cd on human skin are still not well known. In this study, normal human skin keratinocytes (HaCaT cells) were studied for changes in cell viability, morphology, DNA damage, cycle, apoptosis, and the expression of endoplasmic reticulum (ER) stress-related genes (XBP-1, BiP, ATF-4, and CHOP) after exposure to Cd for 24 h. We found that Cd decreased cell viability in a concentration-dependent manner, with a median lethal concentration (LC₅₀) of 11 µM. DNA damage induction was evidenced by upregulation of the level of γ-H2AX. Furthermore, Cd induced G0/G1 phase cell cycle arrest and apoptosis in a dose-dependent manner and upregulated the mRNA levels of ER stress biomarker genes (XBP-1, BiP, ATF4, and CHOP). Taken together, our results showed that Cd induced cytotoxicity and DNA damage in HaCaT cells, eventually resulting in cell cycle arrest in the G0/G1 phase and apoptosis. In addition, ER stress may be involved in Cd-induced HaCaT apoptosis. Our data imply the importance of reducing Cd pollution in the environment to reduce its adverse impacts on human skin.

Convolutional neural networks-based health risk modelling of some heavy metals in a soil-rice system

The long-term consumption of heavy metal-rich rice can cause serious harm to human health. However, the existing health risk assessment (HRA) can only be performed after the rice has been harvested, and this approach belongs to a passive and lagging pattern. This study is the first to explore the feasibility of health risk (HR) prediction by proposing the indirect model CNNHR-IND and the direct model CNNHR-DIR based on the convolutional neural network (CNN) technology. The dataset included 390 pairs of soil-rice samples collected from You County, China, with 17 environmental covariates. The R² values for CNNHR-IND for non-carcinogenic and carcinogenic risks were 0.578 and 0.554, respectively, and those for CNNHR-DIR were 0.647 and 0.574, respectively. The results demonstrated that both models performed well, especially CNNHR-DIR had a higher estimation accuracy. The spatial autocorrelation analysis indicated that CNNHR-DIR exerted no systematic bias in the prediction results for health risks, confirming the rationality of the CNNHR-DIR model. The sensitivity analysis further confirmed the generalizability and robustness of CNNHR-DIR. This study proved the feasibility of HR prediction and the potential of CNN technology in HRA, and is significant regarding early risk warnings of rice planting and the sustainable development of public health.

How Does Adjacent Land Use Influence Sediment Metals Content and Potential Ecological Risk in the Hongze Lake Wetland?

Metal pollution in lake wetlands has become increasingly serious in China and worldwide due to the rapid growth of urbanization and agricultural activities. However, comprehensive assessments of metal pollution in lake wetland sediments that are associated with land use change have been limited from an international perspective. Metal concentrations (As, Cd, Cr, Cu, Hg, Mn, Pb, and Zn) were measured in the surface soils and surrounding sediments of five land use types in the eastern Hongze Lake wetlands, including Farmland (FL), Culture Ponds (CP), Reed Land (RL), Poplar Forests (PF), and Willow Forests (WF). The metal pollution status was assessed using the geo-accumulation index and the potential ecological risk index; The results showed that the average concentrations of As, Cd, Mn, and Zn in the surface soils and As, Cd, Cu, and Zn in the sediments, exceeded the background values of Jiangsu Province, China. The FL soils and surrounding sediments were moderately contaminated with As, whereas the sediments surrounding the CP were uncontaminated to moderately contaminated with Cd. Metal pollution in both soils and sediments was greater on farmland than on other types of land use. Furthermore, there were significant positive correlations between the values of the soil risk index and the values of the surrounding sediment risk index. Correlation analysis (CA) and principal component analysis (PCA) found that metals may be derived from agricultural activities such as the application of chemical and organic fertilizers, as well as domestic sewage, industrial wastewater, and geological anomalies. These findings shed new light on the quantitative impacts of adjacent land use practices on sediment metal pollution and provide a scientific foundation for wetland management decision-making.

Reliability and accuracy analysis of time-weighted average exposure to heavy metals based on personal exposure

Time-weighted average (TWA) exposure has been used as a surrogate for personal air exposure in some large-scale studies. However, the uncertainties of TWA exposure remain to be determined, although its boundedness has been widely recognized. This study aims to evaluate the reliability and accuracy of TWA exposure based on personal exposure. A total of 180 combined indoor-outdoor-personal air samples were collected of six cities during the non-heating and heating periods. The personal exposure levels of Hg, As, Cd, and Pb were 0.16, 21.20, 0.74, and 34.47 ng/m³ in the non-heating period, respectively, but were 0.20, 34.53, 3.45, and 18.59 ng/m³ in the heating period, respectively. The ratios of TWA and personal exposure of heavy metal(loid)s ranged from 0.91 to 1.53. Indoor pollution was the most significant factor of TWA exposure, accounting for 78.3-97.6% and 88.4-98.6% in the heating and non-heating period, respectively. Based on the results of redundancy analysis and risk assessment by TWA exposure, we concluded that TWA exposure could be used for qualitative investigation, as a substitute for personal exposure, but it may result in large bias when used for quantitative investigation. Larger sample size and more exposure scenarios can reduce the estimation error of TWA.

Wood vinegar facilitated growth and Cd/Zn phytoextraction of Sedum alfredii Hance by improving rhizosphere chemical properties and regulating bacterial community

Soil Cd and Zn contamination has become a serious environmental problem. This work explored the performance of wood vinegar (WV) in enhancing the phytoextraction of Cd/Zn by hyperaccumulator Sedum alfredii Hance. Rhizosphere chemical properties, enzyme activities and bacterial community were analyzed to determine the mechanisms of metal accumulation in this process. Results demonstrated that, after 120 days growth, different times dilution of WV increased the shoot biomass of S. alfredii by 85.2%-148%. In addition, WV application significantly increased soil available Cd and Zn by lowing soil pH, which facilitated plant uptake. The optimal Cd and Zn phytoextraction occurred from the 100 times diluted WV (D100), which increased the Cd and Zn extraction by 188% and 164%, compared to CK. The 100 and 50 times diluted WV significantly increased soil total and available carbon, nitrogen and phosphorus, and enhancing enzyme activities of urease, acid phosphatase, invertase and protease by 10.1-21.4%, 29.1-42.7%,12.2-38.3% and 26.8-85.7%, respectively, compared to CK. High-throughput sequencing revealed that the D 100 significantly increased the bacterial diversity compared to CK. Soil bacterial compositions at phylum, family and genera level were changed by WV addition. Compared to CK, WV application increased the relative abundances of genus with plant growth promotion and metal mobilization function such as, Bacillus, Gemmatimonas, Streptomyces, Sphingomonas and Polycyclovorans, which was positively correlated to biomass, Cd/Zn concentrations and extractions by S. alfredii. Structural equation modeling analysis showed that, soil chemical properties, enzyme activities and bacterial abundance directly or indirectly contributed to the biomass promotion, Cd, and Zn extraction by S. alfredii. To sum up, WV improved phytoextraction efficiency by enhancing plant growth, Cd and Zn extraction and increasing soil nutrients, enzyme activities, and modifying bacterial community.

Convolutional neural network-based applied research on the enrichment of heavy metals in the soil-rice system in China

The enrichment of heavy metals in the soil-rice system is affected by various factors, which hampers the prediction of heavy metal concentrations. In this research, a prediction model (CNN-HM) of heavy metal concentrations in rice was constructed based on convolutional neural network (CNN) technology and 17 environmental factors. For comparison, other machine learning models, such as multiple linear regression, Bayesian ridge regression, support vector machine, and backpropagation neural networks, were applied. Furthermore, the LH-OAT method was used to evaluate the sensitivity of CNN-HM to each environmental factor. The results showed that the R² values of CNN-HM for Cd, Pb, Cr, As, and Hg were 0.818, 0.709, 0.688, 0.462, and 0.816, respectively, and both the MAE and RMAE values were acceptable. The sensitivity analysis showed that the concentrations of Cd and Pb, mechanical composition, soil pH, and altitude were the main sensitive features for CNN-HM. Compared with CNN-HM based on all input features, the performance of the quick prediction model that was based on the sensitive features did not degrade significantly, thereby indicating that CNN-HM has stronger stability and robustness. The quick prediction model has extensive application value for timely prediction of the enrichment of heavy metals in emergencies. This study demonstrated the effectiveness and practicability of CNNs in predicting heavy metal enrichment in the soil-rice system and provided a new perspective and solution for heavy metal prediction.

Natural and anthropogenic sources of potentially toxic elements to aquatic environment: a systematic literature review

Potentially toxic elements (PTEs) constitute a class of metals, semimetals, and non-metals that are of concern due to their persistence, toxicity, bioaccumulation, and biomagnification in high concentrations, posing risks to the ecosystem and to human health. A systematic literature review (SLR) was used in this study to identify natural and anthropogenic sources of PTEs for the aquatic environment. The databases consulted were ScienceDirect, Scopus, and Web of Science, in the period 2000-2020, using specific terms and filters. After analyzing the titles, abstracts, and full texts, 79 articles were selected for the SLR, in which 15 sources and 16 PTEs were identified. The main anthropogenic sources identified were mining, agriculture, industries, and domestic effluents, and the main natural sources identified were weathering of rocks and geogenic origin. Some places where environmental remediation studies can be carried out were highlighted such as Guangdong province, in China, presenting values of Cd, Cr, and Cu exceeding the national legislation from drinking water and soil quality, and Ardabil Province, in Iran, presenting values of As, Cr, Cu, Ni, Zn, and Pb exceeding the standard for freshwater sediments of USEPA, among others places. With the results exposed in this work, the government and the competent bodies of each locality will be able to develop strategies and public policies aimed at the main sources and places of contamination, in order to prevent and remedy the pollution of aquatic environments by potentially toxic elements.

Source Apportionment of Heavy Metal Contamination in Urban-Agricultural-Aquacultural Soils near the Bohai Bay Coast, Using Land-Use Classification and Google Satellite Tracing

Heavy metal concentrations of Cd, As, Pb, Cu, Cr, and Hg were investigated for 86 soil samples in Jinzhou near the Bohai Sea in China, in order to identify what anthropological activities influenced their distribution levels. Ordinary cokriging (OCK) was utilized to map six heavy-metal distributions by incorporating their main environmental influencers. The resultant p values for the six OCK mapping models of 0–2.78% indicated good statistical significance of the models, and the relative mean absolute errors of 4.82–12.53% and relative root mean square errors of 6.23–18.21% indicated allowable predication precision for their concentrations. The contamination distributions by OCK mapping were then graded based on the standards of the China National Environmental Monitoring Center and the Chinese Environmental Protection Administration, which showed that Cu and As contaminations in parts of this area were over the natural level but not polluted, Cr contamination was omnipresent over the natural level in this area and even reached the polluted level in parts of this area. The graded contamination maps that were overlapped with land-use maps and Google satellite maps, as well as the verifications reported in literatures, enabled correlations of the different contamination levels of As, Cu, and Cr with human activities. Resultantly, it indicated that As and Cu contamination over the natural level may be related to agricultural planting and aquacultural activities along the coast of Bohai Bay, with the contaminants transported via watercourses; Cr contamination over the natural level may have been due to vehicle emissions; and, Cr pollution may have been from steel manufacturing and geochemical factories

An integrated approach to quantify ecological and human health risks of soil heavy metal contamination around coal mining area

Soil heavy metals harm ecological biodiversity and human health, and quantifying the risks more accurately is still obscure. In this study, a network environ analysis was applied to quantify risks between ecological communities based on control allocation and human health risk models to calculate human health exposure risks from soil heavy metals around Greenside coal mining in South Africa. Ecological and human health risks were apportioned using PMF model. Results showed assessed heavy metals (mean) exceeded local background content with a cumulative of moderately polluted using pollution load index (PLI). Total initial risk (R_i), the risk to biological organisms from direct soil exposure, was 0.656 to vegetation and 1.093 to soil microorganisms. Risk enters the food web via vegetation and harms the whole system. Integrated risks (initial, direct, and indirect) to vegetation, herbivores, soil microorganisms, and carnivores were 0.656, 0.125, 1.750, and 0.081, respectively, revealing that soil microorganisms are the most risk receptors. Total Hazard Index (HI_T) was <1 for adults (0.574) whereas >1 for children (4.690), signifying severe non-cancer effects to children. Total cancer risk (TCR) to children and adults surpassed the unacceptable limit (1.00E-04). Comparatively, Cr is a high-risk metal accounted for 63.24% (adults) and 65.88% (children) of the HI_T and 92.98% (adults) and 91.31% (children) of the TCR. Four sources were apportioned. Contributions to R_i (soil microorganisms and vegetation) from F3 (industrial), F4 (atmospheric), F2 (coal mining), and F1 (natural) were 42.20%, 24.56%, 23.55%, and 9.68%, respectively. The non-cancer risk from F3 (37.67% to adults and 38.40% to children) was dominant, and TCR to children from the sources except F1 surpassed the unacceptable limit. An integrated approach of risk quantification is helpful in managing risks and reducing high-risk pollution sources to better protect the environment and human health.

Road dust-driven elemental distribution in megacity Dhaka, Bangladesh: environmental, ecological, and human health risks assessment

Road dust, which reflects ambient air quality, receives various pollutants including toxic metal(oid)s from several natural and/or anthropogenic sources. This manuscript reports a comprehensive evaluation of the levels of seventeen metal(oid)s in road dust of a megacity (Dhaka, Bangladesh). Different evaluation approaches were implemented including statistical analysis and GIS mapping, besides environmental, ecological, and human health risk indices. From 30 sampling sites, representative samples were collected, which were analyzed by neutron activation analysis. The average concentrations (± SD) of Na, Mg, Al, Sc, Ti, V, Cr, Mn, Fe, Co, Zn, As, Rb, Sb, Cs, Ba, and W were 11,738 ± 560 µg g^-1, 12,410 ± 1249 µg g^-1, 62,127 ± 5937 µg g^-1, 8.89 ± 0.47 µg g^-1, 5224 ± 1244 µg g^-1, 66 ± 8 µg g^-1, 66.7 ± 6.9 µg g^-1, 547 ± 110 µg g^-1, 25,150 ± 1723 µg g^-1, 8.39 ± 0.65 µg g^-1, 125 ± 17 µg g^-1, 3.63 ± 0.56 µg g^-1, 87 ± 9 µg g^-1, 0.75 ± 0.28 µg g^-1, 4.40 ± 0.48 µg g^-1, 397 ± 87 µg g^-1, and 3.82 ± 1.77 µg g^-1, respectively. The distance-based redundancy analysis showed that the northern region was enriched with Na, Mn, Al, Fe, Zn, and Rb, while the southern region was enriched with Fe, Al, Ti, Cr, and Mg. The GIS mapping shows hot spots of Sc, Cr, Zn, and Cs were observed mostly in heavy traffic areas. Significant positive correlations of Fe-Sc, Al-Mg, V-Mg, V-Al, Cs-Rb, Cs-Sc, Rb-Sc, As-Na, and Cs-Rb invoked their inter-dependency and persistence in road dust. Depending on a set of environmental and ecological index-based calculation, the degree of metal(oid) pollution followed the descending order as W > Sb > Zn > Cr > As > Ti > Sc > V, while no pollution was recorded by Mn, Fe, Al, Rb, Cs, Co, and Ba. Importantly, the total hazard index values for adults and children were higher than unity, indicating potential non-carcinogenic health risks from exposure of road dust. Furthermore, the total carcinogenic risks from Cr and As through ingestion and dermal contact exceeded the standard guideline values. The implementation of different evaluation approaches strengthens the findings of metal(oid) source apportionment.

Amine- and thiol-bifunctionalized mesoporous silica material for immobilization of Pb and Cd: Characterization, efficiency, and mechanism

In this study, a two-step functionalizing strategy by combining co-condensation with grafting procedures was employed to synthesize well-ordered Amino- and Thiol-Bifunctionalized SBA-15 (ATBS) mesoporous silica. Its physicochemical properties, performance, and mechanisms in immobilization of toxic metals Pb and Cd in water and soil were investigated. After bi-functionalization, X-ray diffractometer, transmission electron microscope, and N₂ adsorption-desorption measurements confirmed that the ATBS maintained a highly-ordered mesoporous structure, large surface area and pore volume. The elemental analysis, Fourier transform infrared spectroscopy and X-ray Photoelectron Spectroscopy (XPS) evidenced the successful incorporation of amine and thiol groups into ATBS. These structure and functional characteristics of ATBS benefited Pb and Cd sorption. Sorption isotherms of Pb and Cd were better fit with Sips and Redlich-Peterson models. Sorption kinetics suggested that Pb sorption was mainly regulated by chemical reactions, whereas both diffusion process and chemical reactions were rate-regulating steps in Cd sorption. ATBS showed the maximum sorption capacities for Pb and Cd at 120 and 38 mg g^-1, respectively. The sorption mechanisms revealed by XPS measurements suggested that Cd sorption was mainly attributed to thiol groups while Pb was efficiently bond to both thiol and amino groups. High and stable sorption efficiencies were attained in the pH range of 4-6, with a higher affinity towards Pb than Cd. Furthermore, its ability to immobilize Pb and Cd in soils was examined with an incubation experiment, which showed that ATBS reduced 30-56% of MgCl₂-extractable Pb and Cd in a contaminated soil. The synthesized sorbent via the two-step functionalizing strategy shows high sorption efficiency towards Pb and Cd, and thus it has potential application in remediating Pb and Cd contaminated water and soils.

Assessment of Contents and Health Impacts of Four Metals in Chongming Asparagus-Geographical and Seasonal Aspects

In this paper, the contents of four typical metals (Pb, Cd, Hg, and As) in asparagus, water, and soil from Chongming Island were quantitatively determined by inductively coupled plasma mass spectrometry (ICP-MS). The contents of these metals in asparagus showed a common rule of Pb > As > Cd > Hg in different harvest seasons and regions. Significant seasonal differences were found in the contents by difference analysis, but no obvious regional differences were observed. Furthermore, the asparagus did not accumulate these four metals from the soil in Chongming Island by the assessment of bio-concentration factor. The asparagus was proved safe by the analysis of single-factor pollution index and Nemerow pollution index. Through combining the analysis of the above indexes and the geological accumulation index, we found that 51.62% of soil samples were mildly polluted by cadmium. The results of health risk analysis showed that the risk value of children was higher than that of adults under oral exposure, but the four metals in asparagus possessed no obvious risk to health. The above assessments illustrate that the daily consumption of asparagus in Chongming Island will not cause potential health impacts. It is of benefit to ensure the quality and economic interests of asparagus planting in Chongming Island through the investigation of this study.

Ecological and human health risks from pseudo-total and bio-accessible metals in street dusts

Street dust samples were collected from industrial and commercial cities (Jamshedpur and Ranchi during monsoon and post-monsoon seasons) for detecting the levels of Cr, Cd, Cu, Ni, Pb, Zn, As, Co, Al, and Mn. The industrial city recorded higher metal concentrations compared to commercial. Similar trend of pseudo-total metal concentrations was observed in both the seasons at industrial city (Al > Mn > Zn > Cr > Pb > Cu > Ni > Cd) and only monsoon season at commercial city (Al > Mn > Zn > Cu > Cr > Pb > Ni > Cd). Zn > Cd was the most bioaccessible metal throughout the cities (monsoon and post-monsoon). The geochemical parameters (Igeo, EF, CF) were highest for Cd and lowest for Ni (both cities for the two seasons). Pollution Load Indices (PLI zone) were highest during the post-monsoon season in the industrial city. The highest carcinogenic risk was posed by Cr ranging from 1.87E-05 to 4.80E-05, in both the cities through ingestion and inhalation pathways. Children were found at higher risks, while the bioaccessible fractions posed neither carcinogenic nor non-carcinogenic threats to the population. Principal component analysis and correlation analysis indicated the influence of vehicular and industrial emissions, especially steel industry and coal-based thermal power plants as the major source of metals in street-dust. The outcomes of this work will be useful in providing baseline information of pollution along with their consequent environmental and human health risks of Jharkhand state.

A Food-Safety Risk Assessment of Mercury, Lead and Cadmium in Fish Recreationally Caught from Three Lakes in Poland

Simple Summary

The research aimed to determine the content of lead (Pb), cadmium (Cd), and mercury (Hg) in water, sediment, and freshwater fish species roach (Rutilus rutilus), perch (Perca fluviatilis), and pike (Esox lucius) from the Dratów, Syczyńskie, and Czarne Sosnowickie lakes located on Polesie Lubelskie, Poland, as well as a food safety assessment for the consumer. Pb and Cd were measured by graphite furnace atomic absorption spectrometry, while Hg was measured by cold vapor atomic absorption spectrometry. The research results showed that both the waters and the sediments of the studied lakes are characterised by a low concentration of Pb, Cd, and Hg, which indicates the lack of a moderate influence of anthropopressure on these reservoirs. The range of heavy metal contents in the muscles of roach, pike, and perch for Pb was 0.0399–0.1595, 0.0305–0.0920, and 0.0296–0.1057 mg kg⁻¹, respectively; for Cd 0.0014–0.0095, 0.0010–0.0015, and 0.0020 mg kg⁻¹, respectively; and for Hg 0.0123–0.0499, 0.0185–0.0255, and 0.0216–0.0583 mg kg⁻¹, respectively. The content of heavy metals in fish muscles was low and conformed to requirements as defined in the European Union (EU) food legislation. The health risk assessment with regard to the heavy metal contents in the muscles of fish confirmed the safety of this food for consumers.

Abstract

Heavy metals are introduced into water due to anthropogenic activities and can significantly affect an entire ecosystem. Due to their close integration with the water environment, fish are a sensitive indicator of contamination. In addition, fish is an important element in human diets, therefore, monitoring the concentrations of metallic contaminants in their meat is particularly important for food safety. This study aimed to assess the pollution of water ecosystems with selected toxic heavy metals in lakes Dratów, Czarne Sosnowickie, and Syczyńskie. The concentration of Pb, Cd, and Hg in water, sediment, and freshwater fish muscle tissue was determined, and a food safety assessment was performed. The analysis of water and sediments showed that the sediments were characterised by a significantly higher concentration of heavy metals. Presumably, this ecosystem element plays an important role in the uptake of heavy metal contaminants by fish whose levels were higher in planktonophagous and benthophagous fish species as compared to predatory fish. The food safety assessment showed that amounts of heavy metals in the muscle tissue posed no threat to the health of consumers ingesting that fish species, neither individually (THQ) nor collectively (TTHQ).

Predictive model for cadmium uptake by maize and rice grains on the basis of bioconcentration factor and the diffusive gradients in thin-films technique

It is possible for heavy metals in soils to be adsorbed by crop roots and then accumulated in crops, which eventually causes great health risk when the crops are ingested by humans. Thus, it is valuable to understand the enrichment model of heavy metals in crops. Diffusive gradients in thin-films (DGT) technique, as an in-situ passive sampling method, can be used to evaluate the bioavailable heavy metals contents in soils. In this study, data of the bioavailable cadmium (Cd) in soils determined by DGT and Cd contents uptake in rice and maize grains in Tianjin, Zhejiang and Guangxi provinces of China were collected from previous references in Web of Science. By comparing bioconcentration factors, it was found that the heavy metal concentrations accumulated in rice and maize followed a general order roots > stems or leaves > grains. An accurate and robust model for the prediction of Cd content in maize and rice grains was established based on bioconcentration factor (BCF) and the bioavailable Cd content determined by DGT method, with R² 0.986 and root mean square error (RMSE) 0.128. This result suggests that the DGT method can be good tool for predicting heavy metals uptake in crops.

Assessment of risk of non-cancer disease in contaminated plant (Ocimum basilicum L.) and soil

This study tried to conduct an investigation into the rate of contamination by heavy metals (HMs) in both the soil used in the plantation of the basil (Ocimum basilicum L.) as well as the plant itself. The proposed methodology works by assessing the concentrations of 4 heavy metals, inclusive of Pb, Zn, Ni, and Cd. The target hazard quotient (THQ) and the bioconcentration factor (BCF) were deployed for assessing the rate of contamination by HMs within the plant. The plant samples were also analyzed at different stages of growth (DSG) through inspection of their reaction to electromagnetic waves (EW). The results indicated that the THQ was substantially high for Pb and Zn, indicative of the high contamination of the study samples by the metals thereof. The hazard index (HI) for non-carcinogenic hazards was also measured for the entire HMs at 46.64, denoting a high level of contamination in the basil. BCF results also indicated Cd as the most absorbed contaminant (BCF = 1.88) by the target plant. The optimal vegetation index for assessment of HM contamination in the target plant, on the report of the findings, was identified as PD312. Therefore, utilizing EW, the reaction of contaminated plants in DSG is forecastable.

Effect of soil characteristics on cadmium absorption and plant growth of Theobroma cacao L. seedlings

BACKGROUND

Cadmium uptake by cacao plants can affect plant growth, consumer health and commercialisation. To develop mitigation strategies, it is essential to identify the soil characteristics that could influence this absorption. To determine the relationships between cadmium absorption and the soil characteristics of cacao areas, the responses at concentrations of 0, 2, 5, 10 and 20 μg g^-1 of cadmium in three soils of these areas and an andisol were evaluated, using 120-day-old seedlings of four cultivars of Theobroma cacao L.

RESULTS

In the present study, several relationships were found between chemical and physical soil characteristics and available cadmium, such as real and bulk densities, as well as contents of iron, sand, magnesium, potassium, sodium and copper. Additionally, moderate to strong correlations between potassium (r²  = -0.56) and real density (r²  = 0.42), with foliar cadmium, were found. Moreover, a differential deleterious effect on cacao growth in variables such as biomass was corroborated in cadmium concentrations from 5 μg g^-1 in soils. There were no statistical differences between cultivars with respect to cadmium uptake or plant growth. Finally, a multiple linear regression model is proposed to estimate the foliar cadmium content (r²  = 0.878).

CONCLUSION

Some soil characteristics such as density, as well as sand, clay, aluminium, potassium and iron contents, should be considered before establishing cacao crops to avoid cadmium accumulation. The correlation between potassium with foliar cadmium indicated that potassium could be significant in cadmium uptake mitigation strategies. The high correlation between available cadmium and foliar cadmium indicates that the quantification methodology developed using ethylenediaminetetraacetic acid extractant may be a useful diagnostic tool. © 2021 Society of Chemical Industry.

Comprehensive evaluation of environmental availability, pollution level and leaching heavy metals behavior in non-ferrous metal tailings

Amounts of abandoned non-ferrous metal tailings(NMT) piled in the open air are released under geochemistry and migrated to the surrounding environment, causing severe harm to the environment and human health. It is essential to evaluate the heavy metal pollution of NMT. In this study, RAC, I_geo, EF, and RI were used to evaluate the heavy metal pollution risk of NMT. To uniformly simplify the four evaluation results into a comprehensive evaluation result that can reflect the degree of heavy metal pollution risk. Assuming heavy metals' concentration, occurrence, and mobility make the same contribution to the degree of heavy metal pollution. Score the above four evaluation results according to the pollution level, and then weigh the scores to obtain a complete integral result: CRS_Mo (17) > CRS_Cd (13) > CRS_Pb (11) > CRS_Sr(8) > CRS_Mn(7) > CRS_Cu(5) > CRS_Ni(4) > CRS_Cr(3) = CRS_Zn(3). Five higher risk heavy metal elements Mo, Cd, Pb, Sr, and Mn, were found. Cu, Ni, Cr, and Zn are at lower risk. The results showed that Mo, Mn, and Sr's evaluation is more accurate. Pb and Cd have not reached the detection limit for the time being, indicating that the release of heavy metal elements in tailings is not only related to the total concentration, occurrence state, and mobility of heavy metals but also affected by the pH of the tailings. This study's most significant finding is to propose a comprehensive integration result of pollution risk levels based on RAC, I_geo, EF, and RI as the comprehensive evaluation result of heavy metal pollution risk. Simultaneously, this research is also a valuable supplement to the existing risk assessment of heavy metal pollution.

The Concentration of Selected Heavy Metals in Muscles, Liver and Kidneys of Pigs Fed Standard Diets and Diets Containing 60% of New Rye Varieties

Simple Summary

Modern varieties of cereal grains commonly cultivated in Europe are considered good alternative energy sources that can be used as partial replacements for barley and wheat, which are commonly used as primary energy sources in pig feed. In Central Europe, rye deserves special consideration as it can be cultivated on low-fertility soils with a very low environmental impact among cereals. The objective of the present study was to evaluate the effect of partial substitution of wheat and barley with maize or modern rye varieties (population and hybrid) on concentration of selected heavy metals in feed offered to pigs and in pig muscles, liver and kidneys at slaughter.

Abstract

The carry-over of heavy metals from feed to muscles is generally low if animals are fed with a standard diet containing amounts below the maximum permissible levels. However, prolonged exposure to heavy metals can lead to their accumulation in some organs like muscles, liver, and kidneys. This paves the way for human health risks related to the consumption of products of animal-origin. Thus, using feed mixtures with a low level of heavy metals in pig production will contribute to increasing public health and safety and is of environmental concern. The study aimed to assess the impact of the level of some heavy metals (Cd, Pb, Hg, Cu, Zn, Fe and Mn) in standard (control) feed mixtures and in alternative feed mixtures based on maize or new rye varieties (population and hybrid) on the heavy metal concentration in muscles, liver and kidney of fattened pigs at slaughter. While some differences between heavy metals content in examined tissue samples from experimental groups were observed, all of them were in the range of allowable levels according to European Community rules. In conclusion, new rye varieties, especially the hybrid variety, could be an alternative source of cereal grains for pig nutrition.

Characteristics, source apportionment and health risk assessment of heavy metals exposure via household dust from six cities in China

To investigate the characteristics and health risks of heavy metals in household dust in urban and rural areas during heating and non-heating period in 2016-2017, 762 dust samples and 381 questionnaires from 381 households were collected from Dalian, Taiyuan, Lanzhou, Shanghai, Wuhan, and Chengdu in China. The results indicated that Dalian was the most polluted city, while Shanghai and Chengdu were the least polluted cities during the study period. Longer ventilation times led to higher concentrations of heavy metals, and the weighting of heating duration exceeded that of heating type. Soil was the dominant contributor to household dust for Hg, Ni, Cu, Zn, and As, whereas Pb primarily originated from traffic. The non-carcinogenic and carcinogenic risks associated with heavy metals in household dust were acceptable, with ingestion being the primary exposure route. The risk of adverse health effects caused by heavy metal intake via household dust in urban areas was higher than that in rural areas, and increased during household heating period. Ingestion was the most significant route leading to adverse health effects due to heavy metals in household dust. The exception was the carcinogenic risk associated with Ni, which is known to enter the human body mainly via inhalation.

Risk Assessment for Oral Bioaccessibility of Lead and Cadmium in the Potato Growing in Smelter-Impacted Soil

Smelting activities are an important source of heavy metals in soil. More seriously, oral ingestion of crops growing in contaminated soil potentially cause harmful effects on human health. The main purpose of this study is to apply the in vitro model (PBET) and Monte Carlo Simulation (MSC) to the health risk assessment process in order to more accurately and realistically evaluate health risks of residents eating contaminated potato. Results indicated in the raw and cooked potato, the bioaccessibility of Pb was 65.9% and 74.5%, and that of Cd was 79.6% and 61.7%, respectively. Additionally, the bioaccessible hazard quotient (BHQ) was less than the permitted level except for the BHQ of Pb for children. This indicated there wasn't potential non-carcinogenic risk for most potato-consumers but the dietary exposure risk for local children cannot be neglected. Sensitivity analysis showed that the bioaccessibility and ingestion rate appeared decisive with respect to potentially deleterious health effects.

Assessment of heavy metal pollution in Yamuna River, Delhi-NCR, using heavy metal pollution index and GIS

The present study was conducted on the river Yamuna, which passes through Delhi-NCR from Baghpat to Chhainssa, a distance of about 125 km, at six sampling locations to evaluate the concentrations of heavy metals in surface water using heavy metal pollution index (HPI) approach. The river serves both urban-industrial and rural areas in the study area; hence, domestic, industrial, and agricultural wastes are being contributed greatly in the contamination of river water. The Yamuna River is one of the major tributaries of the river Ganga originated in the Himalayas and is flowing through a varied geological terrain. Metals such as iron (Fe), copper (Cu), cobalt (Co), zinc (Zn), lead (Pb), cyanide (CN), nickel (Ni), and chromium (Cr) in selected sites of Yamuna River water were determined by using atomic absorption spectrophotometer. The concentrations of Fe, Cu, Co, Zn, Pb, CN, Ni, and Cr in the river water were found to be in the range of 40-190, 50-120, 4-66, 840-1800, 2-40, 100-600, 88-253, and 35-52 μg/L, respectively. The results show that the maximum heavy metal content was found at sampling site S3 (Nizamuddin) followed by S6 (Chhainssa), S4 (Okhla), S1 (Baghpat), S5 (Manjhawali), and S2 (Pachahira). The heavy metal data was integrated in GIS environment for preparing spatial distribution maps of sampling sites. A scatter plot matrix was created to assess the pattern and interrelationships between heavy metals. The average concentration of heavy metals was recorded high, often exceeding the permissible limits for drinking of surface water prescribed by the Bureau of Indian Standards (BIS) and World Health Organization (WHO). Based on HPI (varies from 98.2 to 555.1), about 85% of the river water was classified as highly polluted; hence, it is not recommended for drinking. Overall, significant variations were observed in concentrations of heavy metals from one location to the other which may be because of toxic industrial effluents and domestic sewage wastes being added to the river water by various anthropogenic activities in the study area. The present work highlights the pollution load of heavy metals in the river Yamuna and also advocates an urgent attention towards minimizing the health risk of people residing not only along the river banks and surrounding regions but also for city population.

Toxic metal(loid)s contamination and potential human health risk assessment in the vicinity of century-old copper smelter, Karabash, Russia

Active smelters release high concentration of multiple toxic metal(loid)s into the environment, degrading the soil cover and posing high risks to human health. The present study investigates Cu along with other metal(loids) such as As, Cd, Hg, Co, Mn, Pb and Zn in the soil collected from the vicinity of Cu smelter, Karabash, Russia, and potential health risks to local children and adults were assessed. The average concentrations of Cu, Zn, Pb, As, Cd, and Hg in the exposed soil were 2698, 1050, 702, 392, 9 and 2 mg kg^-1, respectively, which was significantly (p < 0.05) much higher than reference soil: Cu(107), As(18), Cd(0.3), Hg(0.2), Pb(54) and Zn(125) mg kg^-1. The enrichment factor (EF) for Cu, Hg, Pb and Zn showed significant enrichment, whereas very high enrichment was recorded for As (20.0) and Cd (27.6) suggesting the soil was severely affected by smelting activities. The pollution load index was tenfold higher than the acceptable level of one, whereas potential ecological risk factor showed very high potential risks of Cd and Hg, along with a considerable ecological risk of As and Cu. Very high ecological risk index of 1810 indicates severe degradation of environmental ecosystem. The results of EF, Pearson correlation and principle component analysis were complementary and suggest the anthropogenic source of contamination for Cu, As, Pb, Hg and Cd. The present result suggests As > Pb > Cu in the exposed soil were the major contributors for the health risks and account for 81%, 12% and 5%, and 77%, 12% and 8% of hazard quotient for children and adults, respectively. Noticeably, the health risks to local children dwelling in the vicinity of Cu smelter were 12 and 20 times higher than to adult and the acceptable level of one, respectively. Therefore, in order to reduce the health risk due to metal(loid)s, mitigation measures are needed to remediate the pollution of the exposed soil.

Geographical origin differentiation of Chinese Angelica by specific metal element fingerprinting and risk assessment

Traceability offers significant information about the quality and safety of Chinese Angelica, a medicine and food homologous substance. In this study, a systematic four-step strategy, including sample collection, specific metal element fingerprinting, multivariate statistical analysis, and benefit-risk assessment, was developed for the first time to identify Chinese Angelica based on geographical origins. Fifteen metals in fifty-six Chinese Angelica samples originated from three provinces were analyzed. The multivariate statistical analysis model established, involving hierarchical cluster analysis (HCA), principal component analysis (PCA), and self-organizing map clustering analysis was able to identify the origins of samples. Furthermore, benefit-risk assessment models were created by combinational calculation of chemical daily intake (CDI), hazard index (HI), and cancer risk (CR) levels to evaluate the potential risks of Chinese Angelica using as traditional Chinese medicine (TCM) and food, respectively. Our systematic strategy was well convinced to accurately and effectively differentiate Chinese Angelica based on geographical origins.

Spatial assessment of heavy metals contamination in household garden soils in rural Limpopo Province, South Africa

Heavy metal pollution in soil poses a serious health threat to humans living in close proximity and in contact with contaminated soil. Exposure to heavy metals can result in a range of adverse health effects, including skin lesions, cardiovascular effects, lowering of IQ scores and cancers. The main objectives of this study were to (1) use a portable XRF spectrophotometer to measure concentrations of lead (Pb), arsenic (As), mercury (Hg) and cadmium (Cd) in residential soils in rural Giyani in the Limpopo province of South Africa; (2) to assess the spatial distribution of soil metal concentrations; and (3) to assess pollution levels in residential soils. There were elevated levels of As at one of the sites where 54% of soil samples exceeded the Canadian reference levels for As of 20 mg/kg. Using the geoaccumulation index (I_geo) to determine contamination levels of As, 57% of soil samples from the most polluted site were found to be moderately to heavily and extremely contaminated with As (I_geo class 2-5). The site is located near the Giyani Greenstone Belt, which is characterized by abandoned mines and artisanal mining activities. Gold ores are closely associated with sulphide minerals such as arsenopyrite, and these have been found to contain high amounts of As. This study highlighted the potential for soil contamination and the importance of site-specific risk assessment in the context of environment and health impact assessments prior to major developments, including human settlement developments.

Insights into the anthropogenic load and occupational health risk of heavy metals in floor dust of selected workplaces in an industrial city of Iran

The levels of Cd, Cr, Cu, Fe, Mn, Pb and Zn were determined in floor dusts from mechanical (MRWs) and battery repairing workshops (BRWs) in Yazd, Iran. The study aimed to evaluate the anthropogenic contribution to the presence of heavy metals (HMs), the possible sources and the related risks that could arise from occupational exposure in the studied workplace microenvironments. Among the analyzed heavy metals, Cu, Pb and Zn exhibited enhanced concentrations in the floor dusts. The EF calculations showed an extremely severe enrichment of HMs, especially for Cd, Cu and Pb, while floor dusts were characterized as "extremely polluted" with regards to those metals. In any case, both EF and I_geo values were significantly higher in the BRWs. These results were also supported by NIPI and PLI values, while contour maps of PLI values in both MRWs and BRWs outlined workshops in N-NE part of Yazd as more impacted compared to other spatial locations. Principal component analysis (PCA) and Pearson's correlation outscored workshops activities as the principal sources of heavy metals. The health risk assessment suggested considerable non-carcinogenic risks regarding Pb in the BRWs which exhibited HQ_ing (mean 2.91) and HI (mean 3.03) values higher than safe level. Regarding carcinogenic risks, CR values for both Cd and Cr were below the safe level (1.0 × 10^-6). The occupational exposure to Pb was evaluated through the predicted BLL values, where with averages of 3.33 μg/dl and 21.4 μg/dl for MRWs and BRWs workers, respectively, indicated a severe Pb exposure for BRWs workers.