Heavy metal pollution in vegetables grown in the vicinity of a multi-metal mining area in Gejiu, China: total concentrations, speciation analysis, and health risk

Associations of environmental exposure to metals with the risk of hypertension in China

Hypertension contributes largely to the global burden of disease and mortality. Environmental exposure to metals might be a causative factor for hypertension, but the association remains unclear. The present case-control study of 502 hypertension patients and 502 healthy participants aimed to evaluate the potential relationships between the concentrations of 20 metal in urine and the risk of hypertension in a Chinese population. Multivariate logistic analyses adjusted for potential confounders were performed separately considering the effects of single and multi-metal. We found the increasing trends of urinary Fe, Co, Ni, Cu, Zn and Sr quartiles and the decreasing trends of urinary V and Rb quartiles with the ORs for hypertension. These dose-response associations were confirmed in the RCS models and remained robust in the multi-metal model. Urinary Hg quartiles were positively associated with the risk of hypertension in the models of single-metal and multi-metal. Urinary Cd quartiles were inversely associated with the risk of hypertension in the multi-metal model. Besides, modification effects of gender, BMI and smoking status on the associations of the exposure to various metals with the risk of hypertension were also suggested in the subgroup analysis. Our findings suggest that environmental exposure to V, Fe, Co, Ni, Cu, Zn, Rb, Sr, Cd and Hg might be related with the prevalence of hypertension. Further studies with prospective design should be conducted to confirm these findings.

Heavy metal pollution in immobile and mobile components of lentic ecosystems-a review

With growing population and urbanization, there is an increasing exploitation of natural resources, and this often results to environmental pollution. In this review, the levels of heavy metal in lentic compartments (water, sediment, fishes, and aquatic plants) over the past two decades (1997-2017) have been summarized to evaluate the current pollution status of this ecosystem. In all the compartments, the heavy metals dominated are zinc followed by iron. The major reason could be area mineralogy and lithogenic sources. Enormous quantity of metals like iron in estuarine sediment is a very natural incident due to the permanently reducing condition of organic substances. Contamination of cadmium, lead, and chromium was closely associated with anthropogenic origin. In addition, surrounding land use and atmospheric deposition could have been responsible for substantial pollution. The accumulation of heavy metals in fishes and aquatic plants is the result of time-dependent deposition in lentic ecosystems. Moreover, various potential risk assessment methods for heavy metals were discussed. This review concludes that natural phenomena dominate the accumulation of essential heavy metals in lentic ecosystems compared to anthropogenic sources. Amongst other recent reviews on heavy metals from other parts of the world, the present review is executed in such a way that it explains the presence of heavy metals not only in water environment, but also in the whole of the lentic system comprising sediment, fishes, and aquatic plants.

Environmental exposure to metals and the risk of hypertension: A cross-sectional study in China

Metal pollution is a severe environmental issue in China, which has been recently linked with the risk of hypertension. However, relevant epidemiological studies are limited. The present exploratory study was conducted to assess the associations of environmental exposure to metals with the odds of hypertension as well as blood pressure (BP) levels using urine samples in a Chinese general population. From May 2016 to April 2017, a total of 823 eligible participants were consecutively enrolled in our study in Wuhan, China. Hypertension was defined as systolic BP (SBP) of ≥140 mmHg or diastolic BP (DBP) of ≥90 mmHg, a self-reported physician diagnosis, or current use of antihypertensive medication. We used urine samples as biomarkers to reflect the levels of environmental exposure to 20 metals. Multivariable regression models were applied to assess the potential association. Multi-metal models were conducted to investigate the impacts of co-exposure to various metals. Based on the results from various models, positive trends for increased odds of hypertension with increasing quartiles of vanadium (V), iron (Fe), zinc (Zn) and selenium (Se) were suggested. Compared with those in the lowest quartiles, participants in the highest quartiles of V, Fe, Zn and Se had a 4.4-fold, 4.9-fold, 4.2-fold and 2.5-fold increased odds of having hypertension, respectively. High urinary Hg level was found to increase the levels of DBP. Individuals in the highest group of Hg were found to have a 4.3 mmHg higher level of DBP. Our findings suggest that environmental exposure to V, Fe, Zn, Se and Hg might increase the risk of hypertension or elevate the levels of BP. These findings warrant further prospective studies in a larger population.

The influence of bioavailable heavy metals and microbial parameters of soil on the metal accumulation in rice grain

A field-based study was undertaken to analyze the effects of soil bioavailable heavy metals determined by a sequential extraction procedure, and soil microbial parameters on the heavy metal accumulation in rice grain. The results showed that Cd, Cr, Cu, Ni, Pb and Zn concentrations in rice grain decreases by 65.9%, 78.9%, 32.6%, 80.5%, 61.0% and 15.7%, respectively in the sites 3 (far-away), compared with those in sites 1 (close-to). Redundancy analysis (RDA) indicated that soil catalase activity, the MBC/MBN ratio, along with bioavailable Cd, Cr and Ni could explain 68.9% of the total eigenvalue, indicating that these parameters have a great impact on the heavy metal accumulation in rice grain. The soil bioavailable heavy metals have a dominant impact on their accumulation in rice grain, with a variance contribution of 60.1%, while the MBC/MBN has a regulatory effect, with a variance contribution of 4.1%. Stepwise regression analysis showed that the MBC/MBN, urease and catalase activities are the key microbial parameters that affect the heavy metal accumulation in rice by influencing the soil bioavailable heavy metals or the translocation of heavy metals in rice. RDA showed an interactive effect between Cu, Pb and Zn in rice grain and the soil bioavailable Cd, Cr and Ni. The heavy metals in rice grain, with the exception of Pb, could be predicted by their respective soil bioavailable heavy metals. The results suggested that Pb accumulation in rice grain was mainly influenced by the multi-metal interactive effects, and less affected by soil bioavailable Pb.

Understanding the variation of microbial community in heavy metals contaminated soil using high throughput sequencing

To improve the understanding of bacterial community in heavy metals contaminated soils, we studied the effects of environmental factors on the bacterial community structure in contaminated fields located in Shaanxi Province of China. Our results showed that microbial community structure varied among sites, and it was significantly affected by soil environmental factors such as pH, soil organic matter (SOM), Cd, Pb and Zn. In addition, Spearman's rank-order correlation indicated heavy metal sensitive (Ralstonia, Gemmatimona, Rhodanobacter and Mizugakiibacter) and tolerant (unidentified-Nitrospiraceae, Blastocatella and unidentified-Acidobacteria) microbial groups. Our findings are crucial to understanding microbial diversity in heavy metal polluted soils of China and can be used to evaluate microbial communities for scientific applications such as bioremediation projects.

Distribution of potentially toxic elements (PTEs) in tailings, soils, and plants around Gol-E-Gohar iron mine, a case study in Iran

This study investigated the concentration of potentially toxic elements (PTEs) including Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, V, and Zn in 102 soils (in the Near and Far areas of the mine), 7 tailings, and 60 plant samples (shoots and roots of Artemisia sieberi and Zygophylum species) collected at the Gol-E-Gohar iron ore mine in Iran. The elemental concentrations in tailings and soil samples (in Near and Far areas) varied between 7.4 and 35.8 mg kg^-1 for As (with a mean of 25.39 mg kg^-1 for tailings), 7.9 and 261.5 mg kg^-1 (mean 189.83 mg kg^-1 for tailings) for Co, 17.7 and 885.03 mg kg^-1 (mean 472.77 mg kg^-1 for tailings) for Cu, 12,500 and 400,000 mg kg^-1 (mean 120,642.86 mg kg^-1 for tailings) for Fe, and 28.1 and 278.1 mg kg^-1 (mean 150.29 mg kg^-1 for tailings) for Ni. A number of physicochemical parameters and pollution index for soils were determined around the mine. Sequential extractions of tailings and soil samples indicated that Fe, Cr, and Co were the least mobile and that Mn, Zn, Cu, and As were potentially available for plants uptake. Similar to soil, the concentration of Al, As, Co, Cr, Cu, Fe, Mn, Mo, Ni, and Zn in plant samples decreased with the distance from the mining/processing areas. Data on plants showed that metal concentrations in shoots usually exceeded those in roots and varied significantly between the two investigated species (Artemisia sieberi > Zygophylum). All the reported results suggest that the soil and plants near the iron ore mine are contaminated with PTEs and that they can be potentially dispersed in the environment via aerosol transport and deposition.

Improvement in cadmium tolerance of edible rape (Brassica rapa L.) with exogenous application of chitooligosaccharide

Cadmium (Cd) is one of the most toxic heavy metals, which is readily taken up by plant roots and has deleterious effects on crop yield and quality. The study investigated the potential cross-protection roles of chitooligosaccharide (COS) in alleviating Cd toxicity in edible rape (Brassica rapa L.) under greenhouse conditions. The results demonstrated that spraying COS onto the leaves of edible rape could promote the plant growth and leaf chlorophyll contents, decrease the malondialdehyde (MDA) level in leaves as well as the Cd²⁺ concentration in shoots and roots of edible rape under Cd stress. Moreover, exogenous COS could obviously enhance the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX) in edible rape leaves under Cd-toxicity. The alleviation effect of COS on Cd stress was concentration-dependent and COS of 50-100 mg L^-1 showed the best activity. Subcellular distribution experiments further revealed that COS of 50 mg L^-1 decreased the proportion of Cd in the organelle fraction of leaves by 40.1% while increased the proportion of Cd in the soluble fraction by 13.2%. These results indicated that COS had a potential to enhance plant resistance to Cd through promoting antioxidant enzyme activities and altering Cd subcellular distribution.

Phytochelatins play key roles for the difference in root arsenic accumulation of different Triticum aestivum cultivars in comparison with arsenate uptake kinetics and reduction

In the previous studies, we have found that arsenic (As) accumulation in roots of bread wheat (Triticum aestivum L.) seedlings were significantly different among different wheat cultivars, and As(V) tolerant wheat cultivars have much higher capacities of root As accumulation. However, the reason for the difference remains unclear. Four wheat cultivars with high (MM45 and FM8) or low (QF1 and HM29) levels of arsenic (As) accumulation were selected to investigate the relationship between root As(V) uptake kinetics and root As accumulation. MM45 and HM29 were also used to examine As(V) reduction ability and non-protein thiol (cysteine [Cys], glutathione [GSH], and phytochelatins [PCs]) concentrations in wheat seedlings. MM45 had the lowest Michaelis-Menten constant (K_m) and maximum influx rate (V_max). No difference in the K_m values was found among the three other cultivars. No difference in As(V) reduction capacity was observed between MM45 and HM29. GSH and PC₂ were significantly induced by 10 μM As(V) in roots of wheat seedlings, particularly in MM45. Synthesis of GSH and PCs was completely suppressed in the presence of l-buthionine sulfoximine (BSO), a specific inhibitor of γ-glutamylcysteine synthetase. BSO markedly decreased the As tolerance of wheat seedlings and decreased the accumulation of As in roots, but increased As accumulation in shoots. No significant difference in As concentrations was found between MM45 and HM29 under the BSO treatment. GSH and PCs are the reason why As accumulation and As(V) tolerance differ in roots of different wheat cultivars.

Assessment of multiple exposure to chemical elements and health risks among residents near Huodehong lead-zinc mining area in Yunnan, Southwest China

The contents of chemical elements (Cd, Cr, Cu, Pb and Zn) in 11 kinds of crop/vegetables and soils around the Huodehong lead-zinc mining area in Yunnan, Southwest China were determined by using inductive coupled plasma emission spectrometry (ICP-MS). Results showed that element contents in soils decreased in the order of Zn > Pb > Cr > Cu > Cd. The high geo-accumulation indexes (I_geo) showed that cultivated soils near mine were practically polluted by Cd, Pb and Zn. The contents of Cd, Cr and Pb in crop/vegetables samples were significantly higher than the maximum permissible standard set by China. The potential health risk assessments among local residents were evaluated by the hazard index (HI), the total carcinogenic risk (TCR), the target hazard quotient (THQ) and carcinogenic risk (CR), respectively. The results showed that diet was the dominant exposure pathway. The results of HI for adult and child were 6.21 and 6.08, respectively. TCR values of Cr and Cd were more than 10^-4. The THQ decreased in the following order: Cd > Pb > Cu > Zn > Cr. Among all kinds of crop/vegetables, leafy-vegetables were the major source of Cd and Pb exposure, root-vegetable were the important factors for Cu and Zn exposure, but tuber-vegetable were the factors for Cr exposure. The contents of Cd and Pb in human scalp hairs near Huodehong mine were higher than that in S_20km area. Females possessed a higher risk for Cd, Cr, Cu and Pb exposure than males in study area. Significant differences between ages were found for Cd, Cu and Pb (p < 0.01). This study provided a powerful basis for the coordination of local environmental protection and economic sustainable development and assessing chemical elements risk to human health.

Heavy metals bioconcentration from soil to vegetables and appraisal of health risk in Koka and Wonji farms, Ethiopia

Heavy metal accumulation in agricultural crops has grown a major concern globally as a result of a significant health impact on human. The quantification of heavy metals (Cd, Pb, Cr, Zn, Cu, and Ni) in the soil and vegetables at two sites (Koka and Wonji Gefersa) was done using flame atomic absorption spectrophotometer. The mean concentrations of heavy metals in vegetable fields' soil samples obtained from Koka were higher for Pb, Cr, Zn, Cu, and Ni. The overall results of soil samples ranged 0.52-0.93, 13.6-27.3, 10.0-21.8, 44.4-88.5, 11.9-30.3, and 14.7-34.5 mg kg^-1 for Cd, Pb, Cr, Zn, Cu, and Ni, respectively. The concentrations of heavy metals were maximum for Cd (0.41 ± 0.03 mg kg^-1), Pb (0.54 ± 0.11 mg kg^-1), Zn (14.4 ± 0.72 mg kg^-1), Cu (2.84 ± 0.27 mg kg^-1), and Ni (1.09 ± 0.11 mg kg^-1) in Cabbage and for Cr (2.63 ± 0.11 mg kg^-1) in green pepper. The result indicated that Cd has high transfer factor value and Pb was the lowest. The transfer pattern for heavy metals in different vegetables showed a trend in the order: Cd > Zn > Cu > Cr > Ni > Pb. Among different vegetables, cabbage showed the highest value of metal pollution index and bean had the lowest value. Hazard index of all the vegetables was less than unity; thus, the consumption of these vegetables is unlikely to pose health risks to the target population.

Association between heavy metal and metalloid levels in topsoil and cancer mortality in Spain

Spatio-temporal cancer mortality studies in Spain have revealed patterns for some tumours which display a distribution that is similar across the sexes and persists over time. Such characteristics would be common to tumours that shared risk factors, including the geochemical composition of the soil. The aim of this study was to assess the possible association between heavy metal and metalloid levels in topsoil (upper soil horizon) and cancer mortality in mainland Spain. Ecological cancer mortality study at a municipal level, covering 861,440 cancer deaths (27 different tumour locations) in 7917 Spanish mainland towns, from 1999 to 2008. The elements included in this analysis were Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn. Topsoil levels (partial extraction) were determined by ICP-MS at 13,317 sampling points. For the analysis, the data on the topsoil composition have been transformed by the centred logratio (clr-transformation). Principal factor analysis was performed to obtain independent latent factors for the transformed variables. To estimate the effect of heavy metal levels in topsoil composition on mortality, we fitted Besag, York and Mollié models, which included each town's factor scores as the explanatory variable. Integrated Nested Laplace Approximation (INLA) was used as a tool for Bayesian inference. All results were adjusted for sociodemographic variables. The results showed an association between trace contents of heavy metals and metalloids in topsoil and mortality due to tumours of the digestive system in mainland Spain. This association was observed in both sexes, something that would support the hypothesis that the incorporation of heavy metals into the trophic chain might be playing a role in the aetiology of some types of cancer. Topsoil composition and the presence of potentially toxic elements in trace concentrations might be an additional component in the aetiology of some types of cancer, and go some way to determine the ensuing geographic differences in mortality in Spain. The results support the interest of inclusion of heavy metal levels in topsoil as a hypothesis in analytical epidemiological studies using biological markers of exposure to heavy metals and metalloids.

Effects of Surface Charge and Functional Groups on the Adsorption and Binding Forms of Cu and Cd on Roots of indica and japonica Rice Cultivars

This work was designed to understand the mechanisms of adsorption of copper (Cu) and cadmium (Cd) on roots of indica and japonica varieties of rice. Six varieties each of indica and japonica rice were grown in hydroponics and the chemical properties of the root surface were analyzed, including surface charges and functional groups (-COO- groups) as measured by the streaming potential and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). Binding forms of heavy metals adsorbed on rice roots were identified using sequential extraction methods. In rice roots exposed to Cu and Cd solutions, Cu existed mainly in both exchangeable and complexed forms, whereas Cd existed mainly in the exchangeable form. The amounts of exchangeable Cu and Cd and total adsorbed metal cations on the roots of indica varieties were significantly greater than those on the roots of japonica varieties, and the higher negative charges and the larger number of functional groups on the roots of indica varieties were responsible for their higher adsorption capacity and greater binding strength for Cu and Cd. Surface charge and functional groups on roots play an important role in the adsorption of Cu and Cd on the rice roots.

Endogenous trans-zeatin content in plants with different metal-accumulating ability: a field survey

A field survey was conducted to evaluate soil metal pollution and endogenous trans-zeatin content in the leaves of plants growing at six sites in a metal-polluted area located in Gejiu, Yunnan, China. Five plant species were collected, and the physicochemical properties and concentrations of five metals in the soil were analyzed. The trans-zeatin content in plant leaves was measured by high-performance liquid chromatography. Based on the Nemerow pollution index, the six sites were classified into four levels of pollution (i.e., low, medium, high, and severely high). The degree of soil metal pollution was cadmium (Cd) > arsenic (As) > lead (Pb) > zinc (Zn) > copper (Cu). The leaf trans-zeatin content in Pteris vittata (an arsenic hyperaccumulator) increased significantly by 98.6 % in soil with a severely high level of pollution compared with soil at a low level of pollution. However, in non-hyperaccumulators Bidens pilosa var. radiata and Ageratina adenophora, a significant decrease in leaf trans-zeatin content of 35.6 and 87.6 %, respectively, was observed. The leaf trans-zeatin content in Artemisia argyi also decreased significantly by 73.6 % in high metal-polluted soil compared with that in medium metal-polluted soil. Furthermore, significant correlations were observed between leaf trans-zeatin content in Pteris vittata and As, Pb, and Cd concentrations in the soil; however, either no correlation or a negative one was observed in the other plant species. Therefore, a high content of trans-zeatin in the leaves of Pteris vittata may play an important role in its normal growth and tolerance to metals.

The accumulation and health risk of heavy metals in vegetables around a zinc smelter in northeastern China

Mining and smelting activities engender soil contamination by metals severely. A field survey was conducted to investigate the present situation and health risk of heavy metals (Cd, Pb, Zn, Cu, Cr, As, and Hg) in soils and vegetables in the surrounding area of an 80-year-old zinc smelter in northeastern China. Soil pH, organic matter (SOM), and cation exchange capacity (CEC) were determined, and their relations with heavy metal contents in edible parts of vegetables were analyzed. Results showed that the smelting had led to the significant contamination of the local soils by Cd and Zn, with average concentrations of 3.88 and 403.89 mg kg^-1, respectively. Concentrations of Cd and Zn in greenhouse soils were much lower than those in open farmland soils. Cd concentrations in vegetable edible parts exceeded the permissible limits severely, while other metal concentrations were much lower than the corresponding standards. Leaf and root vegetables had higher concentrations and bioaccumulation factors (BCFs) of Cd than fruit vegetables. Hazard quotient and hazard index showed that cadmium is imposing a health risk to local residents via vegetable consumption. Cd uptake of some vegetables can be predicted by empirical models with the following parameters: soil pH, SOM, CEC, Zn concentrations, and Cd concentrations. Vegetables such as cabbage, Chinese cabbage, tomato, cucumber, and green bean were screened out as being suitable to grow in the studied area.

Arsenic and chromium topsoil levels and cancer mortality in Spain

Spatio-temporal cancer mortality studies in Spain have revealed patterns for some tumours which display a distribution that is similar across the sexes and persists over time. Such characteristics would be common to tumours that shared risk factors, including the chemical soil composition. The objective of the present study is to assess the association between levels of chromium and arsenic in soil and the cancer mortality. This is an ecological cancer mortality study at municipal level, covering 861,440 cancer deaths in 7917 Spanish mainland towns from 1999 to 2008. Chromium and arsenic topsoil levels (partial extraction) were determined by ICP-MS at 13,317 sampling points. To estimate the effect of these concentrations on mortality, we fitted Besag, York and Mollié models, which included, as explanatory variables, each town's chromium and arsenic soil levels, estimated by kriging. In addition, we also fitted geostatistical-spatial models including sample locations and town centroids (non-aligned data), using the integrated nested Laplace approximation (INLA) and stochastic partial differential equations (SPDE). All results were adjusted for socio-demographic variables and proximity to industrial emissions. The results showed a statistical association in men and women alike, between arsenic soil levels and mortality due to cancers of the stomach, pancreas, lung and brain and non-Hodgkin's lymphomas (NHL). Among men, an association was observed with cancers of the prostate, buccal cavity and pharynx, oesophagus, colorectal and kidney. Chromium topsoil levels were associated with mortality among women alone, in cancers of the upper gastrointestinal tract, breast and NHL. Our results suggest that chronic exposure arising from low levels of arsenic and chromium in topsoil could be a potential risk factor for developing cancer.

Adsorption of Cd(II) by two variable-charge soils in the presence of pectin

Batch experiments were conducted to investigate cadmium(II) (Cd(II)) adsorption by two variable-charge soils (an Oxisol and an Ultisol) as influenced by the presence of pectin. When pectin dosage was less than 30 g kg(-1), the increase in Cd(II) adsorption with the increasing dose of pectin was greater than that when the pectin dosage was >30 g kg(-1). Although both Langmuir and Freundlich equations fitted the adsorption isotherms of Cd(II) and electrostatic adsorption data of Cd(II) by the two soils well, the Langmuir equation showed a better fit. The increase in the maximum total adsorption of Cd(II) induced by pectin was almost equal in both the soils, whereas the increase in the maximum electrostatic adsorption of Cd(II) was greater in the Oxisol than in the Ultisol because the former contained greater amounts of free Fe/Al oxides than the latter, which, in turn, led to a greater increase in the negative charge on the Oxisol. Therefore, the presence of pectin induced the increase in Cd(II) adsorption by the variable-charge soils mainly through the electrostatic mechanism. Pectin increased the adsorption of Cd(II) by the variable-charge soils and thus decreased the activity and mobility of Cd(II) in these soils.

Influence of the metabolic state on the tolerance of Pichia kudriavzevii to heavy metals

This work aims to examine the influence of the metabolic state of the yeast Pichia kudriavzevii on the susceptibility to a metals mixture (5 mg L^-1 Cd, 10 mg L^-1 Pb, and 5 mg L^-1 Zn). Cells exposed to the metals mixture in the presence of 25 mmol L^-1 glucose displayed a higher loss of membrane integrity and proliferation capacity, compared to cells incubated in the absence of glucose. The analysis of the effect of individual metals revealed that glucose increased the toxic effect of Cd marginally, and of Pb significantly. The increased susceptibility to heavy metals due to glucose was attenuated in the simultaneous presence of a mitochondrial respiration inhibitor such as sodium azide (NaN₃ ). ATP-depleted yeast cells, resulting from treatment with the non-metabolizable glucose analogue 2-deoxy-d-glucose, showed an increased susceptibility to heavy metals mixture. Pre-incubation of yeast cells with 1 or 1.5 mmol L^-1 Ca²⁺ reduced significantly (P < 0.05) the loss of membrane integrity induced by the metals mixture. These findings contribute to the understanding of metals mechanisms of toxicity in the non-conventional yeast P. kudriavzevii.

Heavy metal content in vegetables and fruits cultivated in Baia Mare mining area (Romania) and health risk assessment

Information about heavy metal concentrations in food products and their dietary intake are essential for assessing the health risk of local inhabitants. The main purposes of the present study were (1) to investigate the concentrations of Zn, Cu, Pb, and Cd in several vegetables and fruits cultivated in Baia Mare mining area (Romania); (2) to assess the human health risk associated with the ingestion of contaminated vegetables and fruits by calculating the daily intake rate (DIR) and the target hazard quotient (THQ); and (3) to establish some recommendations on human diet in order to assure an improvement in food safety. The concentration order of heavy metals in the analyzed vegetable and fruit samples was Zn > Cu > Pb > Cd. The results showed the heavy metals are more likely to accumulate in vegetables (10.8-630.6 mg/kg dw for Zn, 1.4-196.6 mg/kg dw for Cu, 0.2-155.7 mg/kg dw for Pb, and 0.03-6.61 mg/kg dw for Cd) than in fruits (4.9-55.9 mg/kg dw for Zn, 1.9-24.7 mg/kg dw for Cu, 0.04-8.82 mg/kg dw for Pb, and 0.01-0.81 mg/kg dw for Cd). Parsley, kohlrabi, and lettuce proved to be high heavy metal accumulators. By calculating DIR and THQ, the data indicated that consumption of parsley, kohlrabi, and lettuce from the area on a regular basis may pose high potential health risks to local inhabitants, especially in the area located close to non-ferrous metallurgical plants (Romplumb SA and Cuprom SA) and close to Tăuții de Sus tailings ponds. The DIR for Zn (85.3-231.6 μg/day kg body weight) and Cu (25.0-44.6 μg/day kg body weight) were higher in rural areas, while for Pb (0.6-3.1 μg/day kg body weight) and Cd (0.22-0.82 μg/day kg body weight), the DIR were higher in urban areas, close to the non-ferrous metallurgical plants SC Romplumb SA and SC Cuprom SA. The THQ for Zn, Cu, Pb, and Cd was higher than 5 for <1, <1, 12, and 6% of samples which indicates that those consumers may experience major health risks.

Arsenic: A Review of the Element's Toxicity, Plant Interactions, and Potential Methods of Remediation

Arsenic is a naturally occurring element with a long history of toxicity. Sites of contamination are found worldwide as a result of both natural processes and anthropogenic activities. The broad scope of arsenic toxicity to humans and its unique interaction with the environment have led to extensive research into its physicochemical properties and toxic behavior in biological systems. The purpose of this review is to compile the results of recent studies concerning the metalloid and consider the chemical and physical properties of arsenic in the broad context of human toxicity and phytoremediation. Areas of focus include arsenic's mechanisms of human toxicity, interaction with plant systems, potential methods of remediation, and protocols for the determination of metals in experimentation. This assessment of the literature indicates that controlling contamination of water sources and plants through effective remediation and management is essential to successfully addressing the problems of arsenic toxicity and contamination.