Transfer of metals from soil to vegetables in an area near a smelter in Nanning, China

Health risks to local residents from the exposure of heavy metals around the largest copper smelter in China

Non-ferrous smelting releases lots of heavy metals to the environment. Although numerous studies have focused on pollution in the environment, fewer have studied the adverse health effects. In the current study, samples of food, hair and urine were collected and analyzed for zinc (Zn), iron (Fe), chromium (Cr), nickel (Ni), lead (Pb) and copper (Cu) from residents of 3 villages near the largest copper smelter in China. The estimated daily intake (EDI), target hazard quotient (THQ), and Hazard Index (HI) were used to estimate and analyze the health risks to local residents (children, adults, and seniors). The Zn, Cr, Ni, Fe, Pb and Cu concentrations in food ranged from 16.02 to 61.48 mg kg^-1, 0.23-13.64 mg kg^-1, 0.10-5.90 mg kg^-1, 19.16-170.05 mg kg^-1, 0.15-3.62 mg kg^-1, and 0.53-2.74 mg kg^-1, respectively. Zn, Cr, Ni and Pb concentrations in all vegetables were above the national tolerance limits. Children had higher EDIs of heavy metals than that of adults and seniors. The THQ of single elements and the HI of combined elements indicated that the EDI of Pb and Cu showed the highest potential health risks, followed by the EDI of Zn and Fe, and Ni, Cr. High EDI of heavy metals resulted in much higher concentrations of heavy metals in hair and urine samples than those of normal Chinese residents, showing that residents around the smelter have potential health risks through daily food intake. The main sources of these heavy metals were from the consumption of rice and vegetables and it is imperative that measures should be taken to control this urgent problem.

Heavy metals in food crops: Health risks, fate, mechanisms, and management

Food security is a high-priority issue for sustainable global development both quantitatively and qualitatively. In recent decades, adverse effects of unexpected contaminants on crop quality have threatened both food security and human health. Heavy metals and metalloids (e.g., Hg, As, Pb, Cd, and Cr) can disturb human metabolomics, contributing to morbidity and even mortality. Therefore, this review focuses on and describes heavy metal contamination in soil-food crop subsystems with respect to human health risks. It also explores the possible geographical pathways of heavy metals in such subsystems. In-depth discussion is further offered on physiological/molecular translocation mechanisms involved in the uptake of metallic contaminants inside food crops. Finally, management strategies are proposed to regain sustainability in soil-food subsystems.

Heavy metals in human urine, foods and drinking water from an e-waste dismantling area: Identification of exposure sources and metal-induced health risk

Electronic waste or e-waste dismantling activities are known to release metals. However, the human exposure pathways of metals, and their association with oxidative stress in e-waste dismantling areas (EDAs) remain unclear. In this study, our results revealed elevated geometric mean concentrations in vegetables (Cd 0.096 and Pb 0.35 µg/g fw), rice (Cd 0.15, Pb 0.20, and 12.3 µg/g fw), hen eggs (Cd 0.006 and Pb 0.071 µg/g fw), and human urine (Cd 2.12, Pb 4.98, Cu 22.2, and Sb 0.20 ng/mL). Our calculations indicate that rice consumption source accounted for the overwhelming proportion of daily intakes (DIs) of Cd (61-64%), Cu (85-89%), and Zn (75-80%) in children and adults living in EDA; vegetables were the primary contributors to the DIs of Cd (30-32%); and rice (20-29%), vegetables (28-38%), and dust ingestion (26-45%) were all important exposure sources of Pb. Risk assessment predicted that DIs of Cd, Pb, Cu, and Zn via food consumption poses health risks to local residents of EDAs, and the urinary concentrations of analyzed metals were significantly (Pearson correlation coefficient: r = 0.324-0.710; p < 0.01) associated with elevated 8-OHdG, a biomarker of oxidative stress in humans.

Refined assessment of heavy metal-associated health risk due to the consumption of traditional animal medicines in humans

Little is known about the extent of heavy metal accumulation in traditional Chinese medicines (TCMs). In this study, the levels of lead (Pb), cadmium (Cd), arsenic (As), and mercury (Hg) in traditional animal medicines were monitored using inductively coupled plasma mass spectroscopy (ICP-MS). Additionally, for the first time, a heavy metal risk assessment strategy was used to evaluate the potential risks of traditional animal medicines by calculating estimated daily intake (EDI), target hazard quotient (THQ), and cancer risk (CR). To obtain a refined risk assessment, the frequency of exposure to traditional animal medicines was determined from questionnaire data, and the safe factor for TCM was applied. Based on the standard levels for leech, it was found that earthworm, hive, scorpion, and leech accumulated high levels of heavy metals. The combined THQ (cTHQ) values indicated that ingestion of most traditional animal medicines would not pose a risk to the health of either male or female human beings. However, it was indicated that attention should be paid to the potential risk associated with cicada slough, earthworm, scorpion, turtle shells, and hive. Among heavy metals, As and Hg contributed to a major extent to the risk to human health. The CR assessment for Pb and As indicated that, with the exception of earthworm, the cancer risk was less than the acceptable lifetime risk for both males and females. Owing to the higher body weight, both THQ and CR were generally lower for males than for females.

Trace elements in soil-vegetables interface: Translocation, bioaccumulation, toxicity and amelioration - A review

The contamination of soil and vegetables with trace elements is one of the most severe ecological problems in developing industrialized countries. Trace elements are released into the environment from natural and anthropogenic activities and accumulated in soil and vegetables through various pathways which ultimately affects the human health. The present review aimed at 1) discussing the anthropogenic sources in detail, 2) describing the bioaccumulation, absorption, and transportation of trace elements, 3) exploring the options to reduce the health risk due to consumption of contaminated vegetables, 4) identifying the research and policy gaps related to soil and vegetables contamination with trace elements. Besides these objectives, the present review also detailed the several factors which affect the rate of accumulation, toxicity mechanism, and effects of trace elements on vegetables and humans. Various toxicity indices for health risk assessment have also been described. It is suggested to evaluate the trace metals concentration in irrigation water and soil prior to plant the vegetable to minimize the possible contamination.

Potentially toxic elements in saltmarsh sediments and common reed (Phragmites australis) of Burullus coastal lagoon at North Nile Delta, Egypt: A survey and risk assessment

Burullus lagoon is the second largest lake in Egypt. However, there has never been a comprehensive survey which studied nineteen potentially toxic elements in sediments and plants and evaluated the associated potential risk. Thus, we aimed to study the total and potentially available content of As, Al, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Sb, Se, Sn, Tl, V, and Zn in the sediments and common reed (Phragmites australis) at thirty two sites along the entire lagoon and connected drains. Contamination Factor (CF), Pollution Load Index (PLI), Geo-accumulation Index (I_geo), and Enrichment Factor (EF) were calculated to assess the grade of contamination. Element accumulation factor (AF) and bio-concentration ratio (BCR) were also calculated. Aluminum showed the highest median (mg kg^-1) total content (41,200), followed by Fe (30,300), Mn (704.7), V (82.0), Zn (75.5), Cr (51.2), Cu (47.8), Ni (44.3), As (31.9), Tl (24.6), Co (21.4), Se (20.3), Sb (17.6), Sn (15.6), Mo (11.3), and Hg (16.6 μg kg^-1). Values of the EF, CF, and I_geo showed that the sediments were heavily contaminated with As, Sb, Se, Tl, Mo, Sn, Co, Ni, and Cu. The drained sediment had significantly higher values of total and potentially available element content than the lagoon sediments. Sediments of the middle and western area showed significantly higher contents of total and available elements than the eastern section. The BCR and AF values indicate that the studied plant is efficient in taking up high amounts of Zn, Fe, As, Sn, Tl, Ni, Mo, Mn; then Co, Cu, and V. The results exhibit a dramatic contamination at certain sites of the lagoon, and the studied PTEs have a predominant role in contamination-related ecological risk. Further investigations concerning redox-induced mobilization of PTEs in sediments, the risk of fish contamination and the potential health hazards are highly recommended.

Spatial distribution of heavy metals in crops in a wastewater irrigated zone and health risk assessment

Industrialization and urbanization have produced a large amount of wastewater. Part of the municipal wastewater has been used as an irrigation source in urban/suburban areas. Its utilization, although economically beneficial, can significantly deteriorate the integrity of the ecological systems (e.g., in terms of quality of soil and resulting food products). The objectives of this study are to investigate the spatial distribution and bio-accumulation of heavy metals (e.g., Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn) in food crops (and topsoil) and associated health risks of their consumption in the area of Mangla Dam, Pakistan. To this end, studies were conducted to assess the risk factors such as the bioconcentration factor (BCF), health risk index (HRI), and daily intake of heavy metals (DIM). Accordingly, there was more contamination in Mangla Dam water irrigated zone (DWI) than in the groundwater irrigated zone (GWI). Co exhibited the maximum BCF of 7.45 for Eruca sativa and 6.61 for Brassica campestris in the GWI zone. Likewise, enhanced risk to human health was seen from of Cd, Cr, and Pb in Triticum aestivum and Eruca sativa grown in the DWI zone. It is recommended that the quality profile of wastewater discharge into freshwater ecosystems should be continuously monitored and regulated.

Prediction of cadmium concentration in brown rice before harvest by hyperspectral remote sensing

Cadmium (Cd) contaminated rice has become a global food security issue. Hyperspectral remote sensing can do rapid and nondestructive monitoring of environmental stress in plant. To realize the nondestructive detection of Cd in brown rice before harvest, the leaf spectral reflectance of rice exposed to six different levels of Cd stress was measured during the whole life stages. In addition, the dry weight of rice grain and Cd concentrations in brown rice were measured after harvest. The impact of Cd stress on the quantity and the quality of rice grain and on the leaf reflectance of rice was analyzed, and hyperspectral estimation models for predicting the Cd content in brown rice during three growth stages were established. The results showed that rice plants can impact the quality of the brown rice seriously, even if the impact on the quantity was not significant. All the established models had the capability to estimate Cd concentrations in brown rice (R² > 0.598), and the best performance model, with the R² value of 0.873, was use first derivative spectrum of booting stage as variable. It was concluded that the hyperspectral of rice leaves provides a new insight to predict Cd concentration in brown rice before harvest.

Assessment of heavy metals (total chromium, lead, and manganese) contamination of residential soil and homegrown vegetables near a former chemical manufacturing facility in Tarnaveni, Romania

Our aim was to assess local population exposure to heavy metals resulting from soil and vegetable contamination in Tarnaveni, Romania, an area located near a former chemical factory. We collected residential soil and vegetable samples from Tarnaveni and measured chromium (Cr), lead (Pb), and manganese (Mn) levels by atomic absorption spectrometry. We evaluated the relationship between soil and vegetable metals and the distance from the shuttered chemical factory, and calculated the hazard index to assess local population metal exposure via contaminated vegetable ingestion. Soil metal concentrations ranged between 15.6 and 525.8 mg/kg for total Cr, between 25.4 and 559.5 mg/kg for Pb, and between 363.1 and 1389.6 mg/kg for Mn. We found average concentrations of 17.8 mg/kg for total Cr, 2.2 mg/kg for Pb, and 116.6 mg/kg for Mn in local vegetables. We found soil concentrations for all three metals that exceeded normal background levels according to Romanian regulations (Pb exceeded 100 mg/kg in some of the samples), as well as measurable concentrations of metals in all analyzed vegetable samples. These preliminary data underscore a need for a more extensive investigation into associated adverse health effects in the exposed population.

Concentration and potential source identification of trace elements in wet atmospheric precipitation of Shiraz, Iran

The aim of this study was to investigate the concentration of trace elements in wet atmospheric precipitation samples collected at six stations in Shiraz, southwest of Iran and identify their possible sources. In this study, 36 rainwater samples were collected from five urban stations and one suburban station during the rainy season spanning 2016 to 2017. Samples were analyzed for 19 trace elements using inductively coupled plasma-atomic emission spectrometry (ICP-AES). Principal component analysis (PCA) with varimax-normalized rotation was used to identify potential sources of the elements measured in the wet atmospheric precipitation. Crustal enrichment factors (EFs) were also calculated, using Al as the reference element, to determine possible effects of human activities on element levels. Results showed that Al, with a mean concentration of 429.6 μg/l, had the highest measured concentration. The average concentrations of Fe, Zn, Mn, Ba, Cu, Pb and Ni were 305.7, 62.8, 23.9, 21.1, 14.4, 10.3 and 4.1 μg/l, respectively. The pH of the analyzed samples ranged from 4.5 to 6.9, with an average of 3.5. EF analyses showed that samples were not enriched with Fe, Ba, Li, Co, Cr or Mn but were fairly to extremely enriched with Zn, Cu, Pb and Ni. PCA resulted in four factors with eigenvalues greater than unity, which explained 78.8% of total variance.

Assessment of Trace Metal and Metalloid Accumulation and Human Health Risk from Vegetables Consumption through Spinach and Coriander Specimens Irrigated with Wastewater

This study focused on evaluating the metal and metalloid contamination and associated risks in the two vegetables crops, coriander (Coriandrum sativum) and spinach (Spinacia oleracea) treated with three water regimes, canal water, groundwater and municipal wastewater. These vegetables are widely consumed by people and are also used in traditional medicine for treating various disorders. Metal and metalloid accumulation (Zn, Pb, Se, Cu, As, Mo, Fe, Ni) was found higher in vegetables treated with wastewater. Wastewater treated soil had high pollution load index. Fe, Zn, As and Pb had higher values in water, soil and vegetables as compared to other studied metals. Overall, metal correlation for soil and vegetables was significant and positive except for Fe and Cu in spinach. The highest value for daily metal intake was estimated for Fe while Se had the lowest value for the same index. It was thus concluded that trace metal and metalloid accumulation was a major health concern for the public consuming these vegetables.

Phytoavailability of potentially toxic elements from industrially contaminated soils to wild grass

Topsoil and grass samples from 14 sites located in different distances from three copper mining factories and a copper smelter were collected in Srednogorie, Bulgaria. The paper discusses results of studies on the mobility of potentially toxic elements (As, Cd, Cr, Cu, Mn, Ni, Pb, Zn) from contaminated soils to wild grass Cynodon dactylon in terms of transfer (TF: soil to plant) and phytoavailability (PF: EDTA (ethylenediaminetetraacetic acid)-soluble to plant) factors. Soils located close to mine and smelter factories were heavily contaminated by As and Cu reaching levels up to 500 mg/kg and 2400 mg/kg, respectively for As and Cu. At seven sites arsenic and copper in grass were over the normal levels (1 mg/kg As; 20 mg/kg Cu). The content of Cu in grass averaged 63 mg/kg exceeding the maximum allowable for sheep. Relationship between PF and TF values was found for As, Cd, Cu, Ni, Pb, Zn but not for Mn and Cr. To some extent the soil pH, TOM (total organic matter) and CaCO₃ content are related to the phytoavailability of As, Cd and Cu since for Zn and Pb this relation is attributed to Al- and Fe-content of soil. Statistically significant correlation coefficients were determined between the EDTA-soluble fraction of soil and content in grass in the case of As, Cd, Cr, Cu, Mn and Pb indicating the suitability of the short procedure for phytoavailability studies of those elements. The application of hierarchical cluster analysis and self-organizing maps of Kohonen made it possible to reveal specific hidden relationships between the soil variables and transfer factors as well as between the sampling locations. This additional information helps in more detailed interpretation of phytoavailability and transfer processes in the region of interest. The novelty in this study is achieved by careful consideration of the possibility of using EDTA extracts of the toxic metals in investigating of the phytoavailability and transfer processes soil/plant. Additionally, chemometric expertise used makes it possible to differentiate the behavior of each toxic metal in the processes studied. The combination of easy option for rapid extraction and intelligent data analysis gives a new perspective for contributions in explanation of the complex interactions between soils and plants when assessing pollution events in a certain environment.

Distribution and Phytoavailability of Potentially Toxic Metals in Different Fe/Mg Mine Tailings

The environmental risk of potentially toxic metals in tailing soils is of universal concern. We conducted a 3-month pot experiment to research the distribution and variations of potentially toxic metals (PTMs), and the translocation and accumulation capability of these metals (Cr, Ni, Mn, Cu, Zu) in natural plants for three Fe/Mg tailing soils (serpentine-type, olivine-type and magnetite-type) with growth of a grass plant-Imperata cylindrica. We used comparative analysis, regression analysis and correlation analysis to process relevant experimental data. Results showed the rhizosphere tailing soils decreased from 3.70% to 16.8%, compared to the bulk soils, after growth of Imperata cylindrica, and the acid soluble fraction of Mn, Cu and Zn increased significantly. Cu and Zn were more bioavailable than other PTMs, especially for serpentine-type tailing soils. Linear regression analysis indicated that non-residual fractions showed different effects on metal concentrations of Imperata cylindrica. The non-residual metal fractions of serpentine-type and olivine-type tailing soils showed better correlations with metal concentrations in grass plants than those of magnetite-type tailing soils. We found that the chemical compositions of tailing soils showed remarkable effects on Ni and Mn compared with other elements, especially Mg and Al. Overall, the grass plant can alter the metal distribution, enhance metal bioavailability and promote land use of Fe/Mg tailing soils.

Effect of brewery spent diatomite sludge on trace metal availability in soil and uptake by wheat crop, and trace metal risk on human health through the consumption of wheat grain

Soil plays a crucial role in food safety as it determines the composition of food at the beginning of the food chain. However, the quality of soil resources in terms of their potential impact on human health caused by harmful elements is poorly understood in Ethiopia due to lack of reliable and appropriate experimental data. In this study, a field experiment was conducted to evaluate trace metal accumulation in soils amended with brewery spent diatomite sludge (BSDS) in comparison to control, recommended inorganic fertilizers (RIF) and integrated BSDS & RIF (BSDS:RIF). Trace metals uptake by wheat crop and the degree of soil contamination, and human health risk were investigated. BSDS application significantly increased the concentration of trace metals (Cu, Zn, Pb and Ni) in soil compared to that in the control, the RIF, and BSDS:RIF applications. It also significantly increased the concentration of Cu, Zn, Pb and Ni in the wheat grain compared to that in the control and the RIF, but the increase was not significantly different from that in BSDS:RIF amendment. All trace metal concentrations in soil and wheat grain (except Pb in wheat grain) were below the maximum permissible limits in some European countries of agricultural soils, and the maximum permissible limit of FAO/WHO. The degree of soil contamination from each of the treatments was below the maximum acceptable degree of contamination. The Health Risk Index (HRI) was <1 for all metals in all treatments. Thus, we conclude that consumption of wheat grain grown on soils amended with BSDS and BSDS:RIF has no human risks and has low likelihood of human exposure to trace metals.

Risk assessment for potentially toxic metal(loid)s in potatoes in the indigenous zinc smelting area of northwestern Guizhou Province, China

We investigated potentially toxic metal (loid)s (arsenic, As; cadmium, Cd; chromium, Cr; copper, Cu; mercury, Hg; lead, Pb; selenium, Se; and zinc, Zn) in agricultural samples (i.e., Solanum tuberosum L. tubers (potatoes) and their planting media) in the indigenous zinc smelting area of northwestern Guizhou Province, China. Based on the pollution index values for As, Cd, Pb and Zn, the order of the samples was as follow: slag > planting soil with slag > planting soil without slag, and the order of the samples in terms of the bioconcentration factor was the opposite. Cr, Cu and Hg were present in the planting soil with and without slag at slight pollution levels, and the other potentially toxic metal (loid)s had different degrees of contamination. Additionally, the potentially toxic metal (loid) contents in potato were under their limit values except for Cd (all samples) and Pb and Se (some samples). All bioconcentration factors for potatoes were below 0.5, and no health risk index value for potatoes was higher than 0.1. Therefore, although no significant health risk associated with potentially toxic metal (loid)s via consuming potato exists for either adult men or women in the research area, the Cd concentration in this crop should be monitored.

Heavy metal accumulation in vegetable species and health risk assessment in Serbia

Continuous monitoring of heavy metal content in vegetables is of high priority for population nutrition control, as well as risk assessment for human health. The chemical composition of plants is a reliable indicator of their contamination by hazardous substances accumulated in the environment as a consequence of inadequately applied agro-technology. The main goal of this study was to examine the quality of vegetables that reach consumer markets as a function of growth location. Samples of 11 of the most common vegetable species used in the human diet were collected during a 4-year survey. Vegetables originated from local farm producers who cultivated them at different locations in Vojvodina Province, Serbia. Many vegetable samples contained disturbingly high levels of the investigated metals: cadmium, lead, nickel, and chromium. The plant species with the highest Cd accumulation was spinach, where Cd leaves exceeded the maximum permissible concentrations (MPCs) in more than half of the analyzed samples from different localities (54%). Pb concentrations in spinach were also higher than MPC values (according to Serbian law 3.0 μg/g) in 46% of all analyzed samples. Results showed that Cr levels in all tested vegetable species were below MPC values recommended by the FAO/WHO organization. The largest chromium accumulator was spinach, with average values of 2.3 μg/g, followed by beetroot and parsnips with an average concentration of 1.4 μg/g. The highest average content of Ni in all analyzed vegetable species was also recorded in spinach leaves, with an average value of 2.2 μg/g, followed by broccoli (1.7 μg/g) and tomatoes (1.5 μg/g).

Source identification and spatial distribution of metals in soils in a typical area of the lower Yellow River, eastern China

In this study, 234 soil samples were recently collected from Gaoqing County (a typical area of the lower Yellow River) to determine the contents of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn. Multivariate statistical analyses such as correlation analysis, principal components analysis, and one-way ANOVA were applied to identify the source of metals in the soil. Geostatistical methods were used to analyze the spatial structure and distribution of the metals. The results indicated that the mean contents of all metals exceeded the background value of the lower Yellow River, especially for As, Cu, and Hg (1.23, 1.20, and 1.29 times that of the BV, respectively), indicating that these metals were enriched in the study area to different degrees. The results derived from multivariate analysis suggested that As, Cd, Cr, Cu, Ni, Pb, and Zn were mainly controlled by the combination of human activities and soil parent material, and the human activities included industrial emissions, traffic emissions, and agricultural practices. In addition, Hg mainly originated from anthropogenic inputs, such as textile printing, plastics processing, and petrochemical engineering. The contents of metals in different types of land use and parent materials are clearly different. The mean content for eight elements in urban construction land was significantly higher than that of the other land use types; in addition to Hg, the mean content of the other elements was the highest in the lacustrine deposit. The elements of As, Cd, Cr, Cu, Ni, Pb, and Zn had similar hotspots in the urban area, indicating the significant human influence. In addition, these seven metals showed high values in the southeast lacustrine deposit area. The high-value areas of Hg were concentrated in the southwest and northeast study area, which were consistent with the spatial pattern of the industrial sites.

Interrelationships of metal transfer factor under wastewater reuse and soil pollution

The transfer of heavy metals under soil pollution wastewater reuse was studied in a Greenhouse experiment using a randomized block design, including 6 treatments of heavy metals mixtures composed of Zn, Mn, Cd, Co, Cu, Cr, Ni, and Pb, where each metal was taking part in the mixture with 0, 10, 20, 30, 40, 50 mg/kg respectively, in four replications. The Beta vulgaris L (beet) was used as a test plant. It was found that the metal transfer factors were statistically significantly related to the: (i) DTPA extractable soil metals, (ii) the soil pollution level as assessed by the pollution indices, (iii) the soil pH, (iv) the beet dry matter yield and (v) the interactions between the heavy metals in the soil. It was concluded that the Transfer Factor is subjected to multifactor effects and its real nature is complex, and there is a strong need for further study for the understanding of its role in metal-plant relationships.

Metal accumulation in Raphanus sativus and Brassica rapa: an assessment of potential health risk for inhabitants in Punjab, Pakistan

Pakistan is an agricultural country and due to the shortage of clean water, most of the irrigated area (32,500 ha) of Pakistan was supplied with wastewater (0.876 × 109 m³/year). Concentrations of heavy metals in radish (Raphanus sativus) and turnip (Brassica rapa) taken from vegetable fields in Sargodha, Pakistan, were measured. Untreated wastewater was used persistently for a long time to irrigate these vegetable fields. A control site was selected that had a history of fresh groundwater irrigation. Mean metal concentrations were found for irrigation water, soil, and vegetables. In irrigation water, concentrations of Mo and Pb at three sites and Se at sites II and III were higher than the recommended limits. In vegetables, concentrations of Mo and Pb were above the maximum permissible limits. High bioconcentration factor was observed for Zn (12.61 in R. sativus and 11.72 in B. rapa) at site I and high pollution load index was found for Pb (3.89 in R. sativus and 3.87 in B. rapa) at site II. The differences in metal concentrations found in samples depended upon different soil nature and assimilation capacities of vegetables at different sites which in turn depended upon different environmental cues. The entrance of metal and metalloids to human body may happen through different pathways; however, the food chain is the chief route through which metals are transferred from vegetables to individuals. Health risk index observed for metals, (Mo, As, Ni, Cu, and Pb) higher than 1 indicated high risk through consumption of these vegetables at three sites.

Arsenic and Other Elemental Concentrations in Mushrooms from Bangladesh: Health Risks

Mushroom cultivation has been increasing rapidly in Bangladesh. Arsenic (As) toxicity is widespread in the world and Bangladesh faces the greatest havoc due to this calamity. Rice is the staple food in Bangladesh and among all the crops grown, it is considered to be the main cause of As poisoning to its population after drinking water. Consequently, rice straw, an important growing medium of mushrooms in Bangladesh, is known to have high As content. The objective of this study was, therefore, to determine the concentrations of As in mushrooms cultivated in Bangladesh and to assess the health risk as well. It also considered other elements, including Cd, Cr, Co, Cu, Pb, Mn, Hg, Ni, and Zn concentrations in mushrooms from Bangladesh. The mean concentrations (mg/kg) of As, Cd, Cr, Co, Cu, Pb, Mn, Hg, Ni, and Zn in mushrooms were 0.51, 0.38, 0.28, 0.01, 13.7, 0.31, 11.7, 0.12, 0.28, and 53.5, respectively. Based on the dietary intake of mushrooms, the weekly intakes of As, Cd, Cr, Co, Cu, Pb, Mn, Hg, Ni, and Zn from mushrooms for adults were 0.0042, 0.0030, 0.0024, 0.0001, 0.1125, 0.0019, 0.1116, 0.0011, 0.0023, and 0.4734 mg, respectively. Due to the low concentrations of As and other trace elements observed in mushrooms from Bangladesh, as well as relatively lower consumption of this food in people’s diet, it can be inferred that consumption of the species of mushrooms analysed will cause no toxicological risk.

Dataset for effect comparison of irrigation by wastewater and ground water on amount of heavy metals in soil and vegetables: Accumulation, transfer factor and health risk assessment

The irrigation source plays an important role in the amount of contaminates in soil and cultivated agricultural products. In this study, the concentration and human health risks of heavy metals (Zn, Mn, Cu, Cr, Cd and Pb) were evaluated in soil, water and vegetables collected from two sites (FGW: Farms irrigated with ground water, FWW: Farms irrigated with wastewater) of Bushehr, Iran. The trend of heavy metals concentration in vegetables from either site was in the following order: Mn ˃ Zn ˃ Cu ˃ Pb ˃ Cr ˃ Cd. Except Cd and Pb, the concentration of heavy metals was in the range of European Union (2006) permissible limit. THQ (Target hazard quotient) values were the highest in Mn followed by the Pb, Cd, Cu, Zn and Cr. Mn, Pb and Cd exceeded safe limit of THQ in several cases, while THQ of other heavy metals was in the range of safe limit. Based on the results, it can be concluded that heavy metals contamination in vegetables grown in Bushehr, especially in FWW site, may pose a great health risks to the local inhabitant through consumption of vegetables. Therefore, it is recommended that the discharge of industrial and municipal wastewater into water resources witch used for vegetable irrigation should be the first step in controlling the level of heavy metals in vegetables.

Heavy metals and lead isotopes in soils, road dust and leafy vegetables and health risks via vegetable consumption in the industrial areas of Shanghai, China

Vegetable fields have a high risk of heavy metal contamination from pollution sources in suburban and industrial areas of cities. Eighty-seven soil samples, 106 leafy vegetables and 48 road dust samples were collected from industrial areas of Shanghai, China. We studied the levels of heavy metals, health risk through consumption of leafy vegetables, and sources of Pb in soils, road dust and leafy vegetables. Soil Cd, Zn, Pb, Cu, Hg and As concentrations exceeded the soil background values in 73.6%, 97.7%, 52.3%, 37.8%, 95.1% and 20.2% soil samples, respectively, but were below the criteria for agricultural soil in China, with the exception of Hg. The concentrations of Cd, Zn, Pb, Cu and As in road dust were significantly higher than concentrations in soils, while Hg concentration in road dust was lower. Cd, Zn, Pb, Hg and Cu concentrations in soils and Zn, Pb and Cu concentrations in road dust were greatest near the municipal solid waste incineration power plant. Heavy metal concentrations in the edible tissues of vegetables were not correlated with their total values in soils and varied among vegetable species. The trends in transfer factors (TFs) in different vegetables were Cd>Zn>Cu>As>Hg>Pb. There was low health risk from heavy metal exposure by consumption of vegetables based on Hazard Quotients (HQ_M): As was the major contributor to HQ_M, followed by Cd and Pb. Parent material of the Yangtze River Estuary was the major source of Pb in soils, while coal-fired, stationary industrial emissions and municipal waste incineration emissions were the major sources of Pb in dust and vegetables based on use of the lead isotopic tracing method. Accumulation of Pb in leafy vegetables was through foliar uptake and directly related to atmospheric Pb.

Challenges in assessing the health risks of consuming vegetables in metal-contaminated environments

A great deal of research has been devoted to the characterization of metal exposure due to the consumption of vegetables from urban or industrialized areas. It may seem comforting that concentrations in crops, as well as estimated exposure levels, are often found to be below permissible limits. However, we show that even a moderate increase in metal accumulation in crops may result in a significant increase in exposure. We also highlight the importance of assessing exposure levels in relation to a regional baseline. We have analyzed metal (Pb, Cd, As) concentrations in nearly 700 samples from 23 different vegetables, fruits, berries and mushrooms, collected near 21 highly contaminated industrial sites and from reference sites. Metal concentrations generally complied with permissible levels in commercial food and only Pb showed overall higher concentrations around the contaminated sites. Nevertheless, probabilistic exposure assessments revealed that the exposure to all three metals was significantly higher in the population residing around the contaminated sites, for both low-, median- and high consumers. The exposure was about twice as high for Pb and Cd, and four to six times as high for As. Since vegetable consumption alone did not result in exposure above tolerable intakes, it would have been easy to conclude that there is no risk associated with consuming vegetables grown near the contaminated sites. However, when the increase in exposure is quantified, its potential significance is harder to dismiss - especially when considering that exposure via other routes may be elevated in a similar way.

Bioavailability and soil-to-crop transfer of heavy metals in farmland soils: A case study in the Pearl River Delta, South China

Soil-bound heavy metals are of great concern for human health due to the potential exposure via food chain transfer. In the present study, the occurrence, the bioavailability and the soil-to-crop transfer of heavy metals in farmland soils were investigated based on data from two agricultural areas, i.e. Sihui and Shunde in South China. Six heavy metals (As, Cu, Hg, Mn, Ni and Pb) were quantified in the farmland soils. The mean single pollution level indices (PI) were all lower than 1 except for Hg in soils from Shunde (PI = 1.51 ± 0.46), suggesting the farmland soils were within clean and slightly polluted by heavy metals. As, Cu, Ni and Pb were found to be mostly present in the non-bioavailable form. The majority of Hg was considered potentially bioavailable, and Mn was found to be largely bioavailable. Soil pH was an important factor influencing bioavailability of soil-bound heavy metals. The concentrations of heavy metals in vegetables from Sihui and Shunde were within the food hygiene standards, while the rice grain from Sihui was polluted by Pb (PI = 10.3 ± 23.4). Total soil concentrations of heavy metals were not correlated to their corresponding crop concentrations, instead, significant correlations were observed for bioavailable concentrations in soil. The results supported the notion that the bioavailability of the investigated heavy metals in the soil was largely responsible for their crop uptake. The soil-to-crop transfer factors based on bioavailable concentrations suggested that Cu, As and Hg in soils of the study area had greater tendency to be accumulated in the vegetables than other heavy metals, calling for further human health assessment by consuming the contaminated crops.

Levels and Health Risk Assessment of Heavy Metals in Soil, Water, and Vegetables of Dar es Salaam, Tanzania

This study assesses heavy metals’ levels in water, soil, and vegetables (Ipomoea batatas (Matembele), Amaranthus hybridus (Mchicha), Abelmoschus esculentus (Bamia), and Solanum melongena (Bilinganya)) from the Chang’ombe police garden located in Temeke district, Tanzania. Also, it examines potential health risks from consumption of the vegetables. The samples of soils, water, and vegetables were randomly collected, processed, and analyzed for heavy metals using Atomic Absorption Spectrophotometry. The heavy metals’ levels in soil, water, and vegetables were in the order of Fe > Zn > Pb > Cu. Among the vegetables, I. batatas had highest heavy metal content followed by A. hybridus, S. melongena, and A. esculentus. The average daily intake for Pb (63 mg/person/day) was above the permissible maximum tolerable daily intake of 0.21 mg/person/day endorsed by WHO/FAO. Hazard quotient of Pb for I. batatas (7.12) and A. hybridus (2.46) as well as the hazard indices of I. batatas (7.99) and A. hybridus (2.88) exceeded unity, signifying presence of health risks from consumption of the vegetables. This study recommends regular monitoring of heavy metals in soils, water, and foodstuffs to prevent excessive accrual in food chain.

Arsenic, lead and cadmium removal potential of Pteris multifida from contaminated water and soil

The main threats to the environment from heavy metals are associated with arsenic (As), lead (Pb) and cadmium (Cd). In this study, the potential of Pteris multifida for removing As, Pb and Cd from hydroponic solution and pot soil was evaluated for the first time. Short-term (5 day) experiments were conducted to assess phytofiltration efficiency of temperate zone fern P. multifida and to compare it with mostly studied tropical zone fern P. vittata. Within 5 days, P. multifida accumulated 33% of As(III), whereas P. vittata could not accumulate that most toxic arsenic species As(III) at all. Long-term hydroponic results showed that 90% of Pb, 50% of As and 36% of Cd were removed by P. multifida. Concentration of As in the frond (22 mg/kg dw) was comparatively higher than other parts of plant and significantly higher concentration of Cd and Pb were stored in root and rhizome. Pot soil experiment of P multifida confirmed the comparative uptake and translocation of As(V), Pb and Cd from soil. Therefore, from the assessment of heavy metal accumulation capacity, translocation and healthy survival for long time, P. multifida was identified as an excellent species for the treatment of multi-metal contaminated water and soil.

Heavy metals in eggs and chicken and the associated human health risk assessment in the mining areas of Singhbhum copper belt, India

Metal contamination was studied in locally rearing chicken and eggs in the environs of mining areas of Singhbhum copper belt. Concentrations of metals were below Indian standards except for Cu, Ni and Zn in the case of chicken at some locations. Estimated daily intake (EDI) and target hazard quotient (THQ) suggested that the metals did not pose risk individually. However, considering the geometric mean of the metals, hazard index (HI) was above unity. Cu, Pb and Co were the key components contributing to a potential noncarcinogenic risk. The HI varied from 0.62 to 1.66 among the locations indicating a considerable heath risk to the consumers of locally reared chicken and eggs around the mining areas. Higher HIs were found at the locations in close vicinity to copper mining and processing units compared to other locations.

Health risk assessment and growth characteristics of wheat and maize crops irrigated with contaminated wastewater

The present study evaluated the effect of untreated wastewater irrigation and its health risks in Triticum aestivum (wheat) and Zea mays (maize) cultivated at south Cairo, Egypt. Morphological measurements (stem and root lengths, number of leaves per plant, and dry weights of main organs) as well as soil, irrigation water, and plant analyses for nutrients and heavy metals were conducted in polluted and unpolluted sites. Wastewater irrigations leads to reduction in the morphological traits of the plants and reduced its vegetative biomass and yield production, with more negative impacts on maize than wheat. The concentrations of Pb, Cd, Cr, and Fe in roots and leaves of wheat were above the phytotoxic limits. Conversely, Pb, Cd, and Fe were significantly high and at phytotoxic concentrations in the leaves of maize at polluted site. The present study indicated that wheat plants tend to phytostabilize heavy metals in their roots, while maize accumulates it more in their leaves. Maize and wheat had toxic concentrations of Pb and Cd in their grains under wastewater irrigation. The health risk index showed values > 1 for Pb and Cd in polluted site for both crops, in addition to maize in unpolluted site. Consequently, this will have greatest potential to pose health risk to the consumers.

Multiple factors impact the contents of heavy metals in vegetables in high natural background area of China

A field survey was conducted to investigate the concentrations of chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb) in vegetables, corresponding cultivated soils and irrigation waters from 36 open sites in high natural background area of Wuzhou, South China. Redundancy analysis, Spearman's rho correlation analysis and multiple regression analysis were adopted to evaluate the contributions of impacting factors on metal contents in the edible parts of vegetables. This study concluded that leafy and root vegetables had relatively higher metal concentrations and adjusted transfer factor values compared to fruiting vegetables according to nonparametric tests. Plant species, total soil metal content and soil pH value were affirmed as three critical factors with the highest contribution rate among all the influencing factors. The bivariate curve equation models for heavy metals in the edible vegetable tissues were well fitted to predict the metal concentrations in vegetables. The results from this case study also suggested that it could be one of efficient strategies for clean agricultural production and food safety in high natural background area to breed vegetable varieties with low heavy metal accumulation and to enlarge planting scale of these varieties.

Energy dispersive X-ray fluorescence detection of heavy metals in Bangladesh cows' milk

It is considered that cow's milk is almost complete food for human as it provides most of the micronutrients and macronutrients. The cow's milks are essential for the growth and development especially for children. The main compositions of cow's milk are protein, fat, carbohydrates, vitamins and minerals which are well defined. Presently, the study of micronutrients and toxic elements in cow's milk has been widely carried out particularly in the industrialized and polluted regions because of its possibility of contamination, and thereby health risk of the consumers. The elemental composition in local cow's milk samples in Bangladesh is not well studied yet. The present study was therefore aimed to determine the level of heavy metals (Cr, Ni, As, Cd, Hg, Pb, Mn, Cu, Zn and Fe) in cow's milk using EDXRF technique. Subsequently, the experimental data was used to calculate the human health risk through the intake of both powder and liquid cows' milk available in Bangladesh. The results showed that powder milk contains significantly higher concentration of heavy metals than liquid milk samples. The HRI (health risk index) and HI (hazard index) values for most of the elements in all milk samples were within the safe limit (<1.0) or close to safe limit (≤1.0) with an exception of Hg. However, HRI value for Hg in powder milk samples for both children and adult showed a value higher than one (>1). MPI (metal pollution index) value for powder milk samples are very high compared to other type of milk samples analyzed in this study. Therefore, it has been suggested that heavy metal contamination through local powder milk samples might have significant negative impact (threat) on human health.

Mercury pollution in vegetables, grains and soils from areas surrounding coal-fired power plants

Mercury contamination in food can pose serious health risks to consumers and coal-fired power plants have been identified as the major source of mercury emissions. To assess the current state of mercury pollution in food crops grown near coal-fired power plants, we measured the total mercury concentration in vegetables and grain crops collected from farms located near two coal-fired power plants. We found that 79% of vegetable samples and 67% of grain samples exceeded the PTWI's food safety standards. The mercury concentrations of soil samples were negatively correlated with distances from the studied coal-fired power plants, and the mercury contents in lettuce, amaranth, water spinach, cowpea and rice samples were correlated with the mercury contents in soil samples, respectively. Also, the mercury concentrations in vegetable leaves were much higher than those in roots and the mercury content of vegetable leaves decreased significantly after water rinses. Our calculation suggests that probable weekly intake of mercury for local residents, assuming all of their vegetables and grains are from their own farmland, may exceed the toxicologically tolerable values allowed, and therefore long-term consumptions of these contaminated vegetables and grains may pose serious health risks.

Heavy metal contamination of freshwater prawn (Macrobrachium rosenbergii) and prawn feed in Bangladesh: A market-based study to highlight probable health risks

An assessment of the dietary risk of heavy metal exposure to humans is important since it is the main source of exposure. This study aimed to estimate the degree of contamination and assess the probable health risk in the prawn food chain. In prawn feed, the concentrations of metals were detected in the following order: Hg > Co > Pb > Cd. The concentrations of heavy metals in prawn were the highest for Co and lowest for Cd. Trace amounts of As and Cr were detected in the analyzed sample. Target hazard quotients for heavy metals for adults were >1 for Pb, Cd, Hg, and Co, and for children, the same were high for Co and Hg, indicating significant health risks upon dietary exposure. All the prawn samples contained nine-fold and fourteen-fold higher concentrations than the maximum acceptable levels for Pb and Hg, respectively (0.5 mg kg^-1; WHO/FAO). Human health risk due to the Co exposure is quite alarming as the level of exposure was found to be very high. In the prawn samples intended for human consumption, the hazard index (HI) was highest in the samples obtained from Bagerhat (3.25 in flesh and 3.26 in skin), followed by the samples obtained from Satkhira (2.84 in flesh and 3.10 in skin) and Dhaka City Corporation (2.81 in flesh and 3.42 in Skin); this indicates a potential risk of prawn consumption obtained from Southeast Bangladesh. This is particularly problematic as this area accounts for the majority of prawn production and export of the country.

A socio-scientific analysis of the environmental and health benefits as well as potential risks of cassava production and consumption

Due to its high adaptability, cassava (Manihot esculenta Crantz) is one of the world's most cultivated and consumed plants after maize and rice. However, there are relatively few scientific studies on this important crop. The objective of this review was therefore to summarize and discuss the available information on cassava cropping in order to promote sustainable practices in terms of production and consumption. Cassava cultivation has been expanding recently at the global scale and is widely consumed in most regions of South America, Africa, and Asia. However, it is also characterized by the presence in its roots of potentially toxic hydrocyanic acid. Furthermore, cassava can also absorb pollutants as it is currently cultivated near roads or factories and generally without consideration for potential sources of soil, water, or atmospheric pollution. Careful washing, peeling, and adequate preparation before eating are therefore crucial steps for reducing human exposure to both environmental pollutants and natural hydrocyanic acid. At present, there is not enough precise data available on this staple food crop. To improve our knowledge on the nutritive benefits versus health risks associated with cassava consumption, further research is necessary to compare cassava cultivars and precisely study the influence of preparation methods.

Nutritional evaluation, bioaccumulation and toxicological assessment of heavy metals in edible fruits of FicussurForssk (Moraceae)

Ficussur (Moraceae) is an indigenous medicinal plant with a wide distribution in Africa. In this study, the nutritional potential fruit of this indigenous plant to meet domestic food demands and reduce food insecurity in KwaZulu-Natal. South Africa, was investigated. The proximate composition and concentrations of metals in the edible fruits collected from eight different sites in KwaZulu-Natal were determined to assess for nutritional value and the concentrations of metals in the growth soil was determined to evaluate the impact of soil quality on elemental uptake. The fruits contained high levels of moisture (88.8%) and carbohydrates (65.6%). The concentrations of elements in the fruits were found to be in decreasing order of Ca>Mg >Fe >Zn>Cu >Mn> Se with low levels of toxic metals (As, Cd, Co and Pb). This study shows that the consumption of the fruits of F. sur can contribute positively to the nutritional needs of rural communities in South Africa for most essential nutrients without posing the risk of adverse health effects.

Biotransfer of Cd along a soil-plant- mealybug-ladybird food chain: A comparison with host plants

Agro-ecosystem contamination by the heavy metals present in different agricultural products is a serious challenge faced by the living organisms. This study explains the cadmium (Cd) transfer from soils contaminated with different cadmium concentrations through a plant (eggplant and tomato) - mealybug (Dysmicoccus neobrevipes) - predator (Cryptolaemus-montrouzieri) food chain. The soils were amended with Cd at the rates of 0, 12.5, 25 and 50 mg/kg (w/w). Our findings showed that considerably higher Cd transfer through tomato plant. Cadmium was biomagnified during soil-root transfer while bio-minimization of Cd was observed for shoot-mealybug - ladybird transfer. Our results further showed sequestration of Cd during the metamorphosis of ladybird beetle whilst transfer of Cd through soil-plant-mealybug-ladybird multi-trophic food chain increased in a dose dependent manner. Our results emphasize the need of further studies to elaborate possible mechanisms of Cd bio-minimization by plants, mealybugs and ladybirds observed during this study.

Accumulation of trace elements in edible crops and poplar grown on a titanium ore landfill

Urban gardening has recently experienced rapid development; however, the risk of the transfer of toxic elements from neighboring industry needs to be evaluated. We performed a multi-elemental analysis with several common edible crops (cucumber, pepper, cabbage, and lettuce) and poplar grown directly on a titanium ore landfill as a maximized scenario of exposure. Despite elevated concentrations of soil Ca, Fe, Mn, and Ti resulting from the industrial process, we did not register higher accumulation of these elements in the edible parts of crops or in poplar leaves grown on red gypsum compared with the control soil. Only S concentrations were higher in plants grown on the red gypsum, especially for cabbage. The principal component analysis among elements for plants grown on red gypsum indicated that S and Mn were accumulated by different plant species than Cd, Cu, and Zn. The poplar clone had a significantly higher transfer of S and Cr than the control and is a suitable tree species for monitoring element transfer to vegetation in this industrial context. By comparing our data with tolerable daily intake (TDI) recommendations, we demonstrated the low risk of cultivating edible crops directly on an industrial substrate in a maximized scenario of exposure, except for Cr, for which the toxicity depends on the bioavailable form. However, we did not consider the cumulative effects of the various elements because there are no current guidelines, and further research is needed to address this question.

Potential health risk assessment of potato (Solanum tuberosum L.) grown on metal contaminated soils in the central zone of Punjab, Pakistan

Metal buildup was estimated in potato (Solanum tuberosum L.), grown in central Punjab, Pakistan. This crop was irrigated with multiple water sources like ground, sewage and canal water. Concentrations of different metals like zinc (Zn), arsenic (As), lead (Pb), iron (Fe), nickel (Ni), molybdenum (Mo), copper (Cu), and selenium (Se) were assessed in the potato crop irrigated with different types of waters. Sewage water treated crop and soil had higher metal concentrations than those treated with other two treatments. All metals had positive and significant correlation except for Mo which was non-significantly correlated between the vegetable and soil. Highest daily intake was observed for Fe (0.267), whereas the lowest was seen for Se (0.003). The enrichment factor and health index varied between 0.135-15.08 and 0.285-83.77, respectively. This study concludes that vegetables cultivated on soil treated with sewage water is a potent threat for human health as the metals manifest toxicity after entering the food chain.

Health risk assessment of heavy metals in wheat using different water qualities: implication for human health

In the recent years, the use of sewage water for irrigation has attracted the attention of arid and semi-arid countries where the availability of fresh water is poor. Despite the potential use of sewage water in crop irrigation as effective and sustainable strategy, the environmental and human risks behind this use need to be deeply investigated. In this regard, an experiment was carried out under field conditions in Nursery, University College of Agriculture Sargodha, to evaluate the possible health risks of undesirable metals in wheat grains. Wheat variety Sarang was cultivated and irrigated with different combinations of ground (GW) and sewage water (SW). The concentrations of heavy metals (Cr, Cd, Ni, and Pb) and trace elements (Cu, Zn, and Fe) in wheat grains as well as in soil were determined. Moreover, the pollution load index (PLI), accumulation factor (AF), daily intake of metals (DIM), and health risk index (HRI) were calculated. Results showed that the concentration trend of heavy metals was Pb<Cr<Cu<Ni<Cd<Zn<Fe and Cr<Cu<Pb<Cd<Ni<Fe<Zn in soil and wheat, respectively. Among metals, Cd concentration in wheat exceeded the permissible limits regardless water quality, whereas Pb concentration in grain was within the acceptable levels as suggested by World Health Organization, when 100 % of SW was used for irrigation. Similar observation was reported for Cd concentration in the soil when wheat was irrigated with 100 % SW. In comparison to soil, the edible part of wheat presented lower concentration of all studied metals, except for Zn which was much higher compared to the tested soil samples. The higher concentration of Zn was responsible for increasing the DIM of Zn where, in average, the highest value was reported, particularly in 75 % SW treatment. This was reflected also in HRI where the maximum value was reported for Zinc under the same treatment. Higher value of HRI for wheat cultivated on polluted soils suggested that appropriate management of cultivated area is necessary for food safety and thus for public health. The results are expected to create awareness among the public on the safety of consuming food products grown in particular areas.

Evaluating heavy metal accumulation and potential health risks in vegetables irrigated with treated wastewater

Effect of irrigation with treated municipal wastewater on the accumulation of heavy metals in soils and food crops and potential health risks to human via consumption of these food crops are evaluated. The higher concentrations of iron (Fe), copper (Cu), chromium (Cr) and zinc (Zn) were found in lettuce, radish and carrots, respectively. However, trace metal levels in all vegetables were far lower than the food safety criteria of World Health Organization and European Union. Bioaccumulation factors (BAF) for heavy metals in different vegetables showed a trend in the order: Fe > Zn > Cu > Cr. The trends of estimated dietary intake (EDIs) for adults were in the order of Fe > Zn > Cr > Cu. The highest level of total coliform was recorded in spinach, followed by radish, egg plant, tomatoes and lettuce. The low uptake of heavy metals by vegetables shows that the health risks for human are insignificant. As the variations in transfer factor of metals is related to absorption capability of vegetables, soil properties and nutrient management, the risk of human exposure to metal contamination can be significantly reduced by selecting appropriate crops.