Heavy Metal Contamination in Urban Surface Soil of Klang District (Malaysia)

This study aimed to determine bioavailability of heavy metal concentrations (Al, Fe, Zn, Cu, Co, Cd, Pb and Cr) in 76 urban surface soil samples of Klang district (Malaysia). This study also aimed to determine health risks posed by bioavailability of heavy metals in urban soil on adults and children. For bioavailability of heavy metal concentrations, a physiologically bioavailability extraction test in vitro digestion model was used. Mean values of bioavailability heavy metal concentrations for this study were found to be the highest in Al (25.44 mg/kg) and lowest in Cr (0.10 mg/kg). Results of Spearman correlation coefficient (r) values showed significant correlations were observed for Al-Fe (r = 0.681), Cd-Co (r = 0.495), Cu-Zn (r = 0.232), Fe-Pb (r = 0.260), Fe-Zn (r = 0.239). For cluster analysis, output showed that these heavy metals could be classified into four clusters: Cluster 1 consisted of Cd, Cr, Co, and Pb; Cluster 2 consisted of Zn and Cu; Cluster 3 consisted of Fe; and Cluster 4 consisted of Al. For Clusters 1 and 2, anthropogenic sources were believed to be the sources, while for Clusters 3 and 4 the heavy metals originated from natural sources. Health risks were determined in adults and children through health risk assessment. For adults, Hazard Quotient (HQ) value was <1, indicating no non-carcinogenic risk, while for children, the HQ value was >1, indicating a non-carcinogenic risk. Meanwhile, for carcinogenic risk, heavy metal contamination in the Klang district might not pose a carcinogenic risk to adults while it may pose a carcinogenic risk to children because TR values in this study were >1.0E-04 for children. Output has identified the general health risk in the Klang district. Moreover, this study's findings will contribute to fill in the gap of knowledge on heavy metals' impacts on human health and urban development in the Klang District.     

Geochemical speciation and ecological risk assessment of heavy metals in surface soils collected from the Yellow River Delta National Nature Reserve,China

In this study, a comprehensive assessment of soil heavy metal (HMs) pollution in the Yellow River Delta National Nature Reserve (YRDNNR) was conducted. Spatial distributions, chemical fractions, and sources of eight HMs (Cu, Zn, Pb, Cr, Cd, Fe, Mn, and Ni) in 46 soil samples in the studied region were analyzed. In addition, the potential risks of the HMs were evaluated. The results showed that the mean concentrations of Cu, Zn, Pb, Cr, Cd, Fe, Mn, and Ni were 19.4, 65.2, 38.4, 55.9, 0.078, 41546.5, 510.3, and 27.5 mg kg^?1, respectively. It indicates that the concentrations of most HMs, with exception of Pb and Fe, in samples were similar to the background value of soil in China. Principal component analysis results showed that the HMs originated mainly from natural sources, but Pb pollution in the studied area was significantly caused by anthropogenic activities. In addition, Ecological risk assessment statistical analysis indicates that the HM contamination level in YRDNNR ranged from low to moderately polluted, however, the environmental risk due to Mn and Pb contamination was high.     

Spatial distribution and human health risk assessment of heavy metals in campus dust: A case study of the university town of Huaxi

Abstract

A detailed investigation was conducted to understand the contamination characteristics of a selected set of heavy metals (HMs) in 34 campus dust samples from Huaxi University Town. The HMs spatial distribution analysis based on ArcGIS software, the geo-accumulation index (I_geo) and health risk model were employed for evaluation, and multivariate statistical methods were used to identify possible sources. Results showed that the mean concentrations of Cu, Zn, Pb, Cr, Ni, and Cd were 68.18, 123.81, 45.26, 140.36, 47.26, and 0.47?mg/kg, respectively. The spatial distribution characteristics displayed that the relatively large concentrations for the analyzed HMs were mainly located at both teaching areas and students’ dormitory areas. The average values of I_geo indicated that HMs contamination level followed the decreasing trend of Cd?>?Cu?>?Cr?>?Pb?>?Ni?>?Zn. The health risk assessment results indicated that HMs in campus dust generally do not pose any immediate health risk for both adult males and adult females but the cumulative effect is a matter of concern. The sources analyses demonstrated that Cu, Zn, Cr, and Cd, primarily from motor vehicle emission and waste incineration, Pb predominantly originated from construction source, while Ni had the mixed sources of nature and traffic.     

Bioaccumulation and translocation of nine heavy metals by Eichhornia crassipes in Nile Delta,Egypt: perspectives for phytoremediation

Abstract

The current research was carried out to estimate the potential of water hyacinth (WH) for removal of nine heavy metals (HMs) from three irrigation canals in Nile Delta. Sampling was achieved in monospecific and homogeneous WH stands at three irrigation canals in the study area, and WH biomass was sampled at monthly intervals from April 2014 to November 2014 using five randomly distributed quadrats (each 0.5?×?0.5?m) at each canal. All HM concentrations were significantly higher in the roots compared with the other WH organs. The WH was recognized by a bioaccumulation factor >1.0 for all HMs. The WH was recognized by translocation factor <1.0 for all HMs (except Pb). In many cases, the concentrations of the HMs in the different organs of WH were correlated with the same HMs in the water. Such correlations indicate that WH reflects the cumulative influences of environmental pollution from the water, and thereby suggesting its potential use in the bio-monitoring of most examined HMs. In conclusion, WH is a promising macrophyte for remediation of irrigation canals polluted with Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn.     

Heavy metal accumulation in rice (Oryza sativa) near electronic waste dumps and related human health risk assessment

This research was conducted to assess heavy metal contamination in the environment and within Oryza sativa. The translocation factors (TFs) and bioaccumulation factors (BAFs) for heavy metals in O. sativa and estimated daily intake (EDI) and health risk index (HRI) were measured. The samples were analyzed for heavy metals using inductively coupled plasma optical emission spectrometry (ICP-OES). Pb and Cr concentrations in water samples within and near the electronic-waste dumping area exceeded water quality standards for surface water sources from the Pollution Control Department in the Ministry of Natural Resources and Environment of Thailand (PCD). The Pb concentration in soil samples within the area also exceeded soil quality standards for habitat and agriculture from PCD. Most of the metals were highly concentrated in roots, except for Mn which has the highest concentration in leaves. Pb concentrations in rice grains exceeded the FAO/WHO standard (0.2 mg/kg). The average TF values for heavy metals from the soil to roots, roots to stems, stems to leaves, and stems to grains were Mn > Pb > Ni > Cr, Mn > Cr > Ni > Pb, Ni > Pb > Mn > Cr, and Pb > Ni > Cr > Mn, respectively. The average BAF values in O. sativa were Mn > Ni > Pb > Cr. The EDI for Cr, Pb, Mn, and Ni via O. sativa consumption were 6.19, 6.02, 370.57, and 3.80 µg/kg/day, respectively. The HRI for Cr, Pb, Mn, and Ni via O. sativa consumption were 0.30, 1.50, 2.60, and 0.002, respectively.     

Source identification and risk assessment of heavy metals in road dust of steel industrial city (Anshan), Liaoning,Northeast China

Abstract

The purpose of the study was to acquire the source and evaluate the risk posed by heavy metals in road dust of steel industrial city (Anshan), Liaoning, Northeast China. Potential ecological risk index (RI), pollution index (PI) and geo-accumulation index (Igeo) were applied to evaluate the heavy metal pollution level, and the carcinogenic risk (RI) and hazard index (HI) were calculated to estimate the human health risk. The geographic information system maps clearly reveal the hot spots of heavy metal spatial distribution. Principle component analysis (PCA) and cluster analysis (CA) classified heavy metals into three groups. The metal Zn and Pb originate from the traffic emission, while Cd, Cr, Fe, Mn, Ni and Sb primarily come from industrial activities. These two pathways were the major source of heavy metals pollution by positive matrix factorization (PMF). The Igeo and PI values of heavy metals were decreased in the following order: Cd?>?Sb?>?Zn?>?Fe?>?Pb?>?Cu?>?Cr?>?Sn?>?Mn?>?Ni. The RI index showed the heavy metals were moderate to very high potential ecological risk. The HI values for children and adults presented a decreasing order of Cr?>?Pb?>?Ni?>?Cu?>?Cd?>?Zn. The HI also predicted a possibility of non-carcinogenic risk for children living in urban areas in comparison with adults.     

Comparative health risk surveillance of heavy metals via dietary foodstuff consumption in different land-use types of Pakistan

This study probes heavy metals (HMs) concentration in groundwater, soil, vegetables, chicken eggs, and buffalo milk samples collected from different land-use types (LUT) with special emphasis on human health risk via their consumption. Our results depicted that HMs (Ni, Cr, Pb, and Cd) concentration in groundwater of all LUT; Cd concentration in agricultural soil; Ni, Cr, Mn, Cd, and Pb concentration in buffalo milk; and Ni, Cd concentration in chicken eggs of all LUT surpassed the recommended permissible limits. While, on the other hand, Cr concentration in industrial and Pb concentration in agricultural LUT also exceeded permissible limits in the case of chicken egg samples. The concentration of Cr, Pb, and Cd in most of the vegetable samples of different LUT also crossed permissible limits. The accumulation factor for selected HMs followed trends for different LUT as Industrial > Agricultural > Residential, showing the transfer of risk from soil to vegetables. Our results for principle component analysis unravel that, unlike residential, industrial, and agricultural, LUT were highly affected from metals contaminations when different environmental matrices were studied. Health risk index (HRI) was chronicled >1 for Cd in groundwater of industrial and residential sites, in the eggs found in the industrial site, and for Pb in groundwater of industrial and agricultural sites due to higher daily intake of metal, while all other HMs revealed HRI < 1 in all LUT.     

Drinking water quality and risk implications for community health: A case study of shallow water wells and boreholes in three major communities in Northern Cross-River,Southern Nigeria

The quality of water sources and its potential health implications to adults and children populations of respective major communities in Northern Cross-River was assessed. Water samples (n = 10/water source/site) were collected from three (Okpoma, Okuku and Ugaga) communities and heavy metal concentrations (Lead (Pb), Cadmium (Cd), Chromium (Cr), Manganese (Mn), Nickel (Ni), Copper (Cu), Cobalt (Co), and Zinc (Zn)) were evaluated using Atomic Absorption Spectrometer (AAS). Overall, Pb, Cd, Ni, and Co were higher than drinking water guidelines, while only Cr, Mn, Cu, and Zn were within the permissible limits. The estimated average daily intake (EADI) and target hazard quotient (THQ) were used to determine risk implications for adult and children consumer populations. The EADI for Pb in adults for borehole water, Pb and Cr by child consumer population for borehole and shallow well water exceeded the reference dose (RfD) by USEPA. The THQ for adult population were >1 for Pb in borehole water and >1 for Pb and Cr across all sites for the child consumer population. Overall, our findings indicate toxicity and higher hazard risk for both adult (Pb) and children (Pb and Cr) populations that source drinking water from borehole and shallow well water in these communities.     

Optimization and/or acclimatization of activated sludge process under heavy metals stress

The present study aimed to overcome the toxicity of the heavy metals load, discharged with the industrial effluents into Alexandria sewerage network, on the activated sludge treatment system through effective acclimation for organic matter and heavy metals removal. Optimization and/or acclimatization of the activated sludge process in the presence of Cu, Cd, Co and Cr contaminating mixed domestic-industrial wastewater was investigated. Acclimatization process was performed through abrupt and stepwise addition of tested metals using sequencing batch reactors treatment approach and evaluated as microbial oxygen uptake rate (OUR), dehydrogenase activity (DHA), organic matter (COD) and heavy metals removal. Abrupt addition of metals adversely affected sludge bioactivity leading to decline in the removal efficiency of the targeted contaminants and loss of floc structure. Metals IC₅₀ confirmed that copper possessed the highest toxicity towards the OUR, DHA activity and COD removal with orders Cu > Cd > Cr > Co; Cu > Cd > Co = Cr and Cu > Cd > Cr > Co, respectively. The highest metal removal was recorded for Cd followed by Co, Cu and finally Cr, most of which was retained in the dissolved influent. However, controlled stepwise application of the tested metals exhibited high sensitivity of DHA and OUR activities only at the highest metal concentrations although enhanced at the lowest concentrations while COD removal was not significantly affected. In conclusion, this approach resulted in adaptation of the system where sludge microbes acquired and developed natural resistance to such metals leading to remarkable enhancement of both organic matter and heavy metals removal.     

Cadmium,chromium, and lead accumulation in aquatic plants and animals near a municipal landfill

This research was conducted to assess the contamination of heavy metals in the water, sediment, aquatic plants and animals around a municipal landfill. The heavy metals were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES). The concentrations of cadmium (Cd), chromium (Cr), and lead (Pb) in water and sediment were Not detected (ND), 0.05 ± 0.98, and 0.02 ± 0.01 mg/L; and 0.47 ± 0.23, 18.65 ± 11.39, and 5.36 ± 2.08 mg/kg, respectively. A total of 24 aquatic plants from 4 species were collected from the municipal landfill. Cd concentrations in all plant species were within the standard, while Cr and Pb exceeded the standard. Forty-four fish from 4 species, 29 freshwater snails from 3 species, 10 freshwater prawns from 1 species, and 9 freshwater crabs from 1 species were collected. Cd and Cr concentrations in 2 species of fish samples exceeded the standard and Pb concentration in all fish species exceeded the standard. Cd and Pb concentrations in all freshwater snails were within the standard, except Cr. Meanwhile, Cd and Pb in freshwater prawns and snails were within the standard, except Cr. Five species of frogs were collected. Cd and Cr concentrations in 2 species exceeded the standard. Pb concentrations in all frog species exceeded the standard. The pattern of metal accumulation was fish > frogs > freshwater snails > freshwater prawns = freshwater crab (Cd), freshwater prawn > frogs > freshwater crab = freshwater snail > fish (Cr), and freshwater prawn > fish > frogs > freshwater snail > freshwater crab (Pb).     

In Vitro Health Risk Assessment of Ingesting Metal-Enriched Soils and Dusts in a Chinese Mining City

To evaluate the potential health hazards caused by extensive vanadium–titanium magnetite mining, bioavailability and bioaccessibility of metals were assessed in the pluralistic mining–agriculture–residential city of Panzhihua, China. Intensive mining and related heavy traffic may have contributed to Ni, Cr, and Zn contamination and Mn and V accumulation in soils and road dusts. The metal bioavailability estimated by water extraction was significantly lower than metal bioaccessibility on the basis of the simple bioaccessibility extraction test. The bioaccessible metal concentrations were significantly and positively correlated with soil/dust total metal concentrations (p < .05). However, bioavailable metal concentrations exhibited no relationship with total metal concentrations except for V. The bioaccessibility of metals significantly varied and exhibited the following order: Pb > Zn > Mn > Ni > V > Cr. Health risk assessment indicated that the carcinogenic and non-carcinogenic risks posed by these metals were at an acceptable level, but Cr in soils of the mining area and V in surface soils along the Jinsha River were close to the safe level for children. Therefore, the potential health risk attributed to the exposure of children to metals in surface soils and road dusts in such areas should not be overlooked.     

Health Risk Assessment of Consumption of Heavy Metals in Market Food Crops from Sialkot and Gujranwala Districts,Pakistan

This study was performed to investigate the potential health risk of heavy metals (HMs) through consumption of market food crops (MFCs) in the Sialkot and Gujranwala districts, Pakistan. Both study areas are located in industrialized regions of the country, where atmospheric pollution is a problem and irrigation of food crops is mostly practiced on the use of wastewater/contaminated water. For the purpose of this study, MFCs samples were collected and assessed for HMs (Cr, Ni, Cd, Pb, Mn, Cu, Zn, and Fe) by using flame atomic absorption spectrophotometry. Concentration of HMs such as Pb and Cd exceeded the Food and Agriculture/World Health Organization's recommended limits in all MFCs, while Cr in most of the vegetables of the Sialkot and Gujranwala districts also exceeded that limit. The health risk index was >1 in Triticum aestivum for Pb and Cd intake in the Sialkot district and only Pb in the Gujranwala district. Therefore, this study suggests pretreatment of wastewater and its utilization for lawns and green belts irrigation, rather than for food crops. This study also suggests a regular monitoring of HMs in the irrigation water, subsequent soil, air, and MFCs in order to prevent or reduce health hazards.     

Effects of Long-Term exposure to Heavy Metals upon Rhizosphere Bacteria from Baia Mare Area (Maramureş County,Romania)

Abstract

The aim of this study was to investigate the extent of heavy metal (HM) pollution and its effect on microorganisms from rhizosphere soil in Baia Mare area (Maramure? County, Romania). Two sites with different contamination degrees were included in the study: one with a long history of mining activities and one within a drinking water safeguard zone. Rhizosphere soil samples were characterized with respect to physico-chemical parameters and the Cd, Cu, Pb and Zn contents. Native bacteria were investigated for HM tolerance and biofilm formation under toxic exposure by the microdilution assay. The most resistant strains were identified and the minimum inhibitory concentrations for HMs were determined. Cd, Cu, Pb and Zn exceeded the intervention threshold in Bozânta tailings site, while Pb content exceeded the intervention level within the area of the drinking water treatment plant. Cd showed a very high potential ecological risk in Bozânta area. The long-term exposure to HMs contributed to the selection of HM-tolerant and weakly adherent strains. Biofouling was significantly reduced under the influence of copper ions. Arthrobacter, Rhodococcus and Acidovorax strains with exceptional resistant profiles were isolated from the tailings site, indicating the important role of native microorganisms in rhizosphere ecosystems of contaminated sites.     

Geochemical baseline establishment and ecological risk evaluation of heavy metals in greenhouse soils from Dongtai,China

Currently, heavy metal (HM) contamination in greenhouse soils is a significant concern due to the rapid expansion of greenhouse agriculture. However, it is difficult to accurately assess HM pollution in greenhouse soils in China due to the lack of local geochemical baseline concentrations (GBCs) or corresponding background values. In the present study, the GBCs of HMs in Dongtai, a representative greenhouse area of China, were established from subsoils using cumulative frequency distribution (CFD) curves. The pollution levels of HMs and potential ecological risks were investigated using different quantitative indices, such as geo-accumulation index (I_geo), pollution index (PI), pollution load index (PLI) and ecological risk index (RI), based on these regional GBCs. The total concentrations of six metals (Cd, Cr, Cu, Ni, Pb and Zn) in surface soils were determined and shown to be lower than the concentrations reported in other greenhouse regions of China. The GBCs of Cd, Cr, Cu, Ni, Pb and Zn were 0.059–0.092, 39.20–54.50, 12.52–15.57, 20.63–23.26, 13.43–16.62 and 43.02–52.65 mg kg⁻¹, respectively. Based on this baseline criterion, Cd, Pb and Zn accumulated in the surface soils because they were present at concentrations higher than their baseline values. The soils were moderately polluted by Cd according to the I_geo values, and the PI results indicated that moderate Cd contamination was present in this area. The large variation of I_geo value of Cd revealed that Cd in this area was likely influenced by agricultural activities. The PLI showed that most of the study area was moderately polluted. However, an analysis of the RI showed that the investigated HMs had low ecological risks. Correlation analysis and principle component analysis suggested that the Cd, Pb and Zn in the greenhouse soils mainly originated from anthropogenic sources (agricultural activities, atmospheric deposition etc.), while Cr, Cu, and Ni originated from natural sources. The findings of this study illustrated the necessity of GBC establishment at the local scale to facilitate more accurate HM evaluation of greenhouse soils. It is advisable to pay more attention to Cd, which could cause environmental problems in the greenhouse system.     

Heavy metal contamination of soil and tree-ring in urban forest around highway in Shanghai,China

The heavy metal (HM) pollution of forest soil has been known as one of the most challenging pollution issues due to their characteristics. In order to know the HM pollution condition in urban forest, identify the possible source of HM, 102 sub-samples of soil in 34 sites and 39 tree rings sub-samples in 7 sites were collected in the outer-ring greenbelt (ORG) in Shanghai, China. Concentrations of Cu, Zn, Pb, and Cd in soil and tree rings were analyzed, and the soil properties pH, total nitrogen, total phosphorous, and organic matter were analyzed too. Geo-accumulation index and potential ecological risk index were used for assessing the contamination level of HMs. Nonparametric tests, one-way analysis of variance, correlation analysis, and principal component analysis were applied. The results showed that: (1) concentrations of Cu, Zn, and Cd in soil were significantly higher than their corresponding background values of Shanghai (BVs); concentrations of Cu, Zn, and Pb in tree rings increased gradually in the past 10 years; (2) Zn and Cd were in unpolluted to moderately polluted level, Cd has moderate degree potential ecological risk; (3) vehicle exhausts and abrasion of vehicle parts of tires and historical agricultural activities were the main sources of HM contamination; (4) Cinnamomum camphora (L.) Presl. has the potential to reconstruct the change of Cu, Zn, and Pb as a bioindicator. In conclusion, Cd should be considered as a priority control component. The relationship between plant and soil should take further focus and more studies of the behavior of HMs in soil and plants are required.     

Fractionation,Source Identification and Risk Assessments for Heavy Metals in Soils near a Small-Scale Industrial Area (Çanakkale-Turkey)

Contamination of soils by heavy metals due to urbanization increases various environmental concerns. The objective of this research was to determine the potential sources of heavy metals in agricultural soils in the vicinity of a small-scale industrial area and to assess their environmental impacts. Soil samples were obtained from 15 different locations near a small industrial area in the Çanakkale province of Turkey. Heavy metal (Cd, Co, Cu, Ni, Pb, Zn) contents of soil samples were determined with four different geochemical fractions via a sequential extraction procedure. The results revealed that pseudo-total heavy metal concentrations were ordered in decreasing order as Zn > Pb > Cu > Ni > Co > Cd. Considering the results, Cd (1.95 ± 0.12 µg/g), Pb (39.21 ± 2.14 µg/g) and Zn (64.99 ± 8.16 µg/g) values were above the normal values specified for agricultural lands. The findings obtained from sequential extraction procedure showed that Cd (78%) and Pb (65%) existed mostly in mobile phases. Such mobile phases originated mostly from anthropogenic sources. These findings were also supported by chemometric analyses. Risk assessments pointed out that while Pb and Zn have moderate risks on the environment, Cd creates high risks.     

Health risk assessment of heavy metals in groundwater of coal mining area: A case study in Dingji coal mine,Huainan coalfield,China

Heavy metals enrichment in groundwater poses great ecological risks to human beings. In the present research work, a total of 59 groundwater samples from 12 sampling points in Dingji coal mine, Huainan coalfield, were collected and measured for Cu, Pb, Zn, Cd, Ni, Mn, Cr, and Fe by inductively coupled plasma mass spectrometry (ICP-MS). The human health risk caused by heavy metals through the pathway of drinking water was evaluated and analyzed using the US Environment Protection Agency (USEPA) evaluation model. It has been found that the carcinogenic risk values were between 1.05 × 10^?5 and 3.5 × 10^?4, all exceeding the maximum acceptable level recommended by the USEPA, and the carcinogenic risk of Cr accounted for 99.67% of the total carcinogenic risk. The non-carcinogenic health risk values were all lower than the negligible level given by the USEPA, and the contribution of non-carcinogenic health risk was in the order of Cr > Zn > Cu / Pb >Mn > Fe > Cd > Ni. Among them, Cr had the largest contribution, accounting for 36% of the total non-carcinogenic risk value. In this study, the carcinogenic risk constituted 99.99% of the total health risk, indicating that the total health risk essentially consisted of carcinogenic risk. The research results suggest that much more attention should be paid to the health risk caused by Cr in the groundwater.     

Assessment of potential health risk of heavy metals in soils from a rapidly developing region of China

Soil heavy metal contamination is a major environmental concern, and health risk associated with heavy metals is not fully explored. A combination of spatial analysis and Monte Carlo simulation was successfully used to identify the possible sources and health risk of cadmium (Cd), arsenic (As), mercury (Hg), lead (Pb), chromium (Cr), and copper (Cu) in soils collected from a rapidly developing region of China. It was found that mean concentrations of Cd (0.17 mg/kg ), As (8.74 mg/kg ), Hg (0.15 mg/kg ), Pb (27.28 mg/kg ), and Cu (33.32 mg/kg ) were greater than the soil background values. Accumulation and spatial variability of heavy metals were significantly affected by anthropogenic activities and soil properties. The risk assessment indicated that non-carcinogenic risk was not significant. However, 95% of the total cumulative carcinogenic risk of children was greater than 1E-05, implying high potential carcinogenic risk with As and Pb representing the major contributors. Ingestion of heavy metals in the soils was the main exposure pathway compared with the inhalation and the dermal exposure. Concentration of heavy metals in the soils, particulate emission factor, and dermal exposure ratio were the major parameters affecting health risk. This study highlights the importance of assessment of soil direct exposure health risk in studying heavy metal exposures.     

Heavy metal accumulation in frogs surrounding an e-waste dump site and human health risk assessment

Abstract

This study was performed heavy metals (As, Cd, Cr, and Pb) in water, soil and frogs around an electronic-waste dump site. The bioaccumulation factors (BAFs) of heavy metals in three frog species and potential human health risks were assessed. Heavy metals were analyzed using inductively coupled plasma-optical emission spectrometry. The Cd and Pb concentrations in water samples and As and Pb concentrations in soil samples from within the e-waste dump site exceeded the standards. The heavy metal concentrations in the muscles of three frog species were as follows: Cr?>?Pb?>?As?>?Cd, and there were no significant differences among frog species except in the case of Pb (p?<?0.05). Only the Cr concentrations exceeded the food quality standards. The relative order of the BAFs for heavy metals in frogs as a result of uptake from the water and soil was Cr?>?As?>?Pb?>?Cd and Cr?>?As?>?Cd?>?Pb, respectively, which indicated that the uptake from water was greater than that from the soil. The assessment of the health risk index and carcinogenic risk (CR) indicated potential human health effects from As, Cr, and Pb via the consumption of frogs.