Elucidation of Contaminant-Induced Toxic Responses in the Biota of Lake Vembanad,Kerala, India

This study investigates the spatial distribution of various organochlorine insecticides (OCIs) and heavy metals in both sediment and a bivalve, Villorita cyprinoides var. Cochinensis, collected from three pristine areas of Lake Vembanad. The detected concentrations of OCIs in the bivalve and sediment are in the order DDT > Heptachlor > BHC and BHC > DDD > heptachlor, respectively. However the DDT concentration (28.5 ng/g) in the bivalve at Chambakkara exceeded the limit suggested by the U.S. Geological Survey's National Water-Quality Assessment Program (NWQAP) and indicated an anthropogenic input source for the parent DDT. The maximum potential contamination indices for Zn and Ni in the bivalve were 267.8 mg/kg and 22.3 mg/kg, respectively. The Enrichment Factor (EF) and geoaccumulation index (I_geo) values of sediment indicated that Cd showed high pollution status and the Biota Sediment Accumulation Factor value of heavy metals suggested that Zn, Cu, and Cd were bioaccumulated in the bivalve's tissue. The concentrations of Zn and Cd were above the threshold levels and regarded as harmful according to the international standard for metals in mollusc compiled by the Food and Agriculture Organization. Therefore, they create great health risk for mussel consumers.     

An Investigation of the Soil Property Changes and Heavy Metal Accumulation in Relation to Long-term Wastewater Irrigation in the Semi-arid Region of Iran

Concentrations and spatial distribution of Zn, Cu, Cd, and Pb along two landscapes including a wastewater-irrigated area and a control area were determined to assess the impact of long-term wastewater irrigation and landscape properties on heavy metal contamination. Some disturbed and undisturbed soil samples were taken from soil trenches and soil cores, located on three main landscape positions (upper slope, midslope, and lower slope) in northwestern Iran. The investigation showed that the mean concentration of the heavy metals followed the order Zn > Cu > Pb > Cd in the wastewater-irrigated soil and Pb > Zn > Cu > Cd in the control soils. On average, compared to similar positions in the control region, the wastewater-irrigated regions contained 3.0 (midslope) to 4.9 (lower slope), 2.7 (midslope) to 4.6 (lower slope), 3.3 (upper slope) to 4.1 (lower slope), and 1.7 (upper slope) to 2.6 (lower slope) times higher amounts of Zn, Cu, Cd, and Pb, respectively. Significant positive relationships (P < 0.05) were recorded between the heavy metals concentration with <0.002 mm particle-size fraction and organic matter content, the fractions linked to runoff and soil erosion. It is believed that the two soil fractions play a crucial role in the distribution of the metals along the wastewater-irrigated landscape. Despite the significant increase of heavy metals (P < 0.05) in the wastewater-irrigated soils compared with control soils, the concentration of all evaluated metals was below the maximum accepted limits (Zn < 300 mg/kg, Cu < 100 mg/kg, Cd < 5 mg/kg, and Pb < 100 mg/kg), and grouped as “not-enriched” to “moderately-enriched” categories regarding the topsoil enrichment index. Overall, the lower slope was shown to be more contaminated with the heavy metals compared to the other positions.     

Metal phytoremediation potential of naturally growing plants on fly ash dumpsite of Patratu thermal power station,Jharkhand, India

Three naturally growing plants Ipomoea carnea, Lantana camara, and Solanum surattense were found in fly ash dumpsite of Patratu thermal power station, Jharkhand, India. They were assessed for their metal uptake potential. The fly ash was slightly alkaline with very less nitrogen and organic carbon but enriched with phosphorus and heavy metals. Lantana camara and Ipomoea carnea showed good translocation from root to shoot for most of the metals except Mn and Pb. The order of metal accumulation in stem of both the plants were Fe(205mg/kg)>Mn(65mg/kg)>Cu(22.35mg/kg)>Pb(6.6mg/kg)>Cr(3.05mg/kg)>Ni(1 mg/kg)>Cd(0.5 mg/kg) and Fe(741 mg/kg)>Mn(154.05 mg/kg)>Cu(20.75 mg/kg)>Pb(6.75 mg/kg)>Ni(4.0 mg/kg)>Cr(3.3mg/kg)>Cd(0.05mg/kg), respectively. But Solanum surattense accumulated most of the metals in roots. The order was in the following order, Mn (382.2mg/kg) >Fe (264.1mg/kg) > Cu (25.35mg/kg) >Pb (5.95 mg/kg) > Ni (1.9 mg/kg) > Cr (1.8mg/kg) > Cd (0.55 mg/kg). The order of Bioconcentration factor (BCF) in root and shoot followed almost the same order as, Mn>Fe>Ni>Pb>Cu>Cr≈ Cd in all the three species. ANOVA showed significant variation in metal accumulation by root and stem between the species. Finally, it can be concluded that Solanum surattense can be used as phytostabilizer and other two species as phytoextractor of metal for fly ash dumpsite reclamation.     

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).     

Aquatic macrophytes mediated remediation of toxic metals from moderately contaminated industrial effluent

The present study assessed Zn, Cr, Cd, and Pb removal efficiency of Colocasia esculenta, Hydrilla verticillata, Phragmitis australis, Typha latifolia, and Spirodella polyrhiza from sewage-mixed industrial effluent. The fresh/dry weight and relative growth rate of each macrophyte decreased with increasing effluent concentration. H. verticillata and C. esculenta exhibited better growth at 50% effluent over control. The maximum Zn, Cd, and Pb accumulation (1008.23, 28.03, and 483.55 mg/kg dry wt., respectively) was recorded in C. esculenta, whereas Cr (114.48 mg/kg dry wt.) in H. verticillata at 100% effluent. Metal accumulation in roots of all plants species was higher (≥50%) initially with increasing effluent concentration and later transferred to shoots. All plants exhibited BCF >1.0 for all heavy metals, highest being for Zn (91.2) and Cd (75.2) in H. verticillata, for Cr (97.9) and Pb (103) in C. esculenta. Except S. polyrhhiza, all other plants exhibited TF <1.0. Maximum removal efficiency of Zn was 82.8% by H. verticillata, whilst that of Cr, Cd, and Pb by C. esculenta at 50% effluent, demonstrating wide applicability of H. verticillata and C. esculenta for treatment of mixed industrial effluent having heavy metals.     

Bioaccumulation of heavy metals in local edible plants near a municipal landfill and the related human health risk assessment

ABSTRACT

The increase in municipal solid waste generation, along with high concentrations of heavy metals in environments near municipal landfill, has led to human health hazards. This study investigated heavy metal contamination in water, sediment, and edible plants near a municipal landfill, including the bioaccumulation factor (BAF) and potential health risks. The heavy metal concentrations in the samples were analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES). The concentrations of arsenic (As), lead (Pb), cadmium (Cd), and chromium (Cr) in water samples were not detected (ND), ND, 0.006 ± 0.01 mg/L, and ND, respectively, and in sediment samples, the concentrations were 1.19 ± 0.44, 3.20 ± 0.62, 0.46 ± 0.21, and 6.97 ± 0.34 mg/kg, respectively. The highest concentrations of As (5.03 ± 0.38), Pb (1.81 ± 0.37), and Cd (1.93 ± 0.13) were found in Marsilea crenata, whereas that of Cr (5.68 ± 0.79) was detected in Ipomoea aquatica. The Cr concentration in all plant species exceeded the standard for vegetables. The BAF values followed the heavy metal concentrations. All plant species have a low potential for accumulating Pb and Cr. The edible plants in this study area might cause health hazards to consumers from As, Pb, and Cd contamination.     

Evaluation of trace metals in sediment,water, and fish (Mugil cephalus) of the central Black Sea coast of Turkey

In this study, concentrations of trace metals such as As, Cd, Cu, Cr, Fe, Pb, Ni, Sn, Se, and Zn were determined in sediments, water, and a kind of fish (Mugil cephalus) of the central Black Sea coasts by employing Inductively Coupled Plasma Mass Spectrometry and microwave digestion technique. Gill, muscle, liver, and other tissues were analyzed separately for each sample. The accuracy of the results were checked by using a certified reference material (DORM-4). In water samples, the metal determined at highest concentrations was Cu (1645.44 µg/L). In sediment samples, the metal determined at highest concentrations was Fe (12223.50 mg/kg). The levels of trace metals found in the different parts of the fish were: Zn in muscle tissue (30393.28 mg/kg), Sn in gill tissue (5140.08 mg/kg), and Cu in liver tissue (289.31 mg/kg). These results were also compared with various relevant guidelines and literature.     

Concentrations of heavy metals in vegetables between 2004 and 2018, and its impacts on human health in China

Abstract

Heavy metals in vegetables are of great concern worldwide due to their potential bioaccumulation in human. This review-based study researched the concentrations of heavy metals in vegetables from all provinces of China between 2004 and 2018, and assessed the health risk for the residents. The results displayed the highest Pb, Cd, Cu, and Zn concentrations in vegetables were 0.192?mg/kg (west area), 0.071?mg/kg (central area), 3.961?mg/kg (central area), and 10.545?mg/kg (central area), which were lower than the maximum allowable concentration. In the national scale, the weighted average level of heavy metals in vegetables was found to be in the order of Zn?>?Cu?>?Pb?>?Cd. The hazard index (HI) of each province showed that beside Anhui and Hunan province, residents in other provinces of China faced a low high risk of Pb, Cd, Cu, and Zn. However, people consuming vegetables faced a high risk of Pb, Cd, Cu, and Zn in Anhui and Hunan provinces. This research may provide insight into heavy metal accumulation in vegetables and forecast to residents to cope with these problems for improved human health.     

Environmental risks posed by heavy metal contamination from mine waste: Case study from northwest Iran

Mining activities produce waste tailings that can be a significant source of pollution in the surrounding ecosystem. This study was designed to estimate the magnitude of Fe, As, Pb, Cd, Mn, Ni, Zn, and Cr in soil impacted by activities in the Moeil iron ore mine area of northwestern Iran and initially assess the potential risk to nearby residents and ecological habitats. For this, concentrations of elements in 24 samples from 8 locations were analyzed by inductivity coupled plasma optical emission spectrometry. Concentrations of heavy metals reported for samples collected from the area ranged from 50,247–466,200 mg/kg for Fe, 40–10,827 mg/kg for As, 9–84 mg/kg for Pb, 0.2–58.4 mg/kg for Cd, 32–424 mg/kg for Mn, 4–32 mg/kg for Ni, 37–60 mg/kg for Zn, and 32–337 mg/kg for Cr. Reported levels of Fe and As in particular are indicative of severe contamination and imply a high risk to ecological receptors. Reported levels of arsenic also imply elevated cancer and non-cancer health risks to residents who work in or pass through the area. Reported levels of Cd and Cr in soil samples also indicate an elevated cancer risk posed by these metals. The result of this study indicates it is important to estimate potential contamination of soils and drinking water wills in the vicinity of Moeil village to arsenic and heavy metals.     

Effect of Arbuscular Mycorrhizal Fungi On Yield and Phytoremediation Performance of Pot Marigold (Calendula officinalis L.) Under Heavy Metals Stress

In order to study the effect of mycorrhizal fungi (inoculated and non-inoculated) and heavy metals stress [0, Pb (150 and 300 mg/kg) and Cd (40 and 80 mg/kg)] on pot marigold (Calendula officinalis L.), a factorial experiment was conducted based on a randomized complete block design with 4 replications in Research Greenhouse of Department of Horticultural Sciences, University of Tehran, Iran, during 2012–2013. Plant height, herbal and flower fresh and dry weight, root fresh and dry weight and root volume, colonization percentage, total petal extract, total petal flavonoids, root and shoot P and K uptakes, and Pb and Cd accumulations in root and shoot were measured. Results indicated that with increasing soil Pb and Cd concentration, growth and yield of pot marigold was reduced significantly; Cd had greater negative impacts than Pb. However, mycorrhizal fungi alleviated these impacts by improving plant growth and yield. Pot marigold concentrated high amounts of Pb and especially Cd in its roots and shoots; mycorrhizal plants had a greater accumulation of these metals, so that those under 80 mg/kg Cd soil^?1 accumulated 833.3 and 1585.8 mg Cd in their shoots and roots, respectively. In conclusion, mycorrhizal fungi can improve not only growth and yield of pot marigold in heavy metal stressed condition, but also phytoremediation performance by increasing heavy metals accumulation in the plant organs.     

Heavy Metal Concentration in Sediments of the Nhue River and its Water-Irrigated Farmland Soil in the Suburbs of Hanoi,Vietnam

The heavy metal pollution of sediment in the Nhue River, which receives wastewater from the To Lich and Kim Nguu River system, was investigated together with the effects of use of this water for irrigation of the surrounding farmland. Eighty soil samples and 40 sediment samples were collected from six locations in the Nhue River and two locations in the To Lich River for chemical and physical analyses. The results showed that the sediments in the Nhue River are heavily polluted by metals (71–420 mg/kg for Cu, 77–433 mg/kg for Pb, 150–350 mg/kg for Zn, 0.7–8.7 mg/kg for Cd, 80– 583 mg/kg for Cr, and 32–70 mg/kg for Ni). There were positive correlations between heavy metal concentration and both clay and organic matter contents in the sediment samples. The concentrations of all metals in soil samples were much higher than the background levels in the farmland, Cd, Cu, and Pb, exceeding Vietnamese standards for agricultural grounds.     

Metal Contamination in Sediment of One of the Upper Reaches of the Yangtze River: Mianyuan River in Longmenshan Region,Southwest of China

Metal contamination in sediment of the Mianyuan River (one of the major upper reaches of the Yangtze River) in Longmenshan Region (China) was investigated in 2012. Means of metal concentrations in sediment (<74μm) were Cr: 59.93 ± 19.8% mg/kg; As: 7.21 ± 50.2% mg/kg; Se: 0.45 ± 66.3% mg/kg; Pb: 19.89 ± 29.3% mg/kg; Zn: 78.98 ± 31.9% mg/kg; Cd: 0.69 ± 28.3% mg/kg; Ba: 0.71 ± 34.0% g/kg; Mn: 0.55 ± 62.2% g/kg. This study suggested: (1) concentrations of Cd, As, Cr, and Pb in Mianyuan River sediment were lower than those of the middle and lower reaches of the Yangtze River; (2) the increase of metals during the period from 2006 to 2009 was probably related to the destruction of tailings piles by the Wen Chun earthquake in 2008; (3) organic materials decided the distribution of Cd, Se, As, Ba, and Mn in the upstream sediment, while the iron and manganese minerals controlled the distribution of Ba, Cr, and Zn in the downstream sediment; (4) sources of Cd, Se, and As were geogenic, while sources of Cr, Zn, Ba, and Mn were anthropogenic; (5) the source of Pb in the upstream sediment was probably automobile exhaust, but that of Pb in the downstream sediment was geogenic.     

Seasonal Variation of Metals in Seawater, Sediment, and Manila Clam Ruditapes philippinarum from China

Concentrations of trace metals (Cu, Pb, Zn, Cd, Cr, Hg, and As) were determined for the first time in seawater, sediment, and Manila clam from Deer Island, Liaoning Province, China. The seawater, sediment, and clam samples were collected seasonally at three clam farming sites around Deer Island during 2010–2011. The average concentrations of Cu, Pb, Zn, Cd, Cr, Hg, and As in the seawater samples were 4.16, 0.72, 5.88, 0.45, 2.51, 0.03, and 1.02 μg/l, respectively. The seasonal variations of trace metals in seawater showed a significant difference in the concentrations of Cu, Pb, Zn, Hg, and As among seasons. The average concentrations of Cu, Pb, Zn, Cd, Cr, Hg, and As in the sediment samples were 6.43, 13.80, 53.08, 1.10, 36.40, 0.05, and 4.78 mg/kg dry weight, respectively. Trace metal concentrations in sediment seasonally varied significantly except for Cd and Hg. The average concentrations of Cu, Pb, Zn, Cd, Cr, Hg, and As in the clam samples were 11.28, 0.61, 92.50, 0.58, 3.98, 0.03, and 1.98 mg/kg dry weight, respectively. Concentrations of Cu, Zn, Cd, Cr, and As in Manila clam showed marked seasonal fluctuations with significant difference. Cu and Zn were the metals with the highest mean biosediment accumulation factor values in Manila clam. Besides, significant correlations for the concentrations of Cu and Zn relative to their concentrations in sediment were also found. Such differences in regression analyzes may be explained by differential bioaccumulation of essential and xenobiotic metals. Concentrations of trace metals in Manila clam did not exceed the maximum established regulatory concentrations for human consumption. Moreover, the calculations revealed that the estimated daily intake values for the examined clam samples were below the internationally accepted dietary guidelines and the calculated hazard quotient values were well less than 1, thus strongly indicating that health risk associated with the intake studied metals through the consumption of Manila clam from Deer Island was absent.     

Interaction of Heavy Metals in Multimetal Biosorption by Galerina vittiformis from Soil

ABSTRACT Soil heavy metal contamination, a major threat due to industrialization, can be tackled by an efficient and economical process called bioremediation. Mushrooms are employed to accumulate heavy metals from soil due to their high metal accumulation potential and better adaptability. The bioaccumulation potential of Galerina vittiformis was already reported for individual metals. At natural conditions, since soil consists of more than one polluting metal, more focus has to be given to multimetal systems. In this study, multimetal accumulation potential was analyzed using central composite design, and the responses obtained were analyzed using response surface methodology. Heavy metals such as Cu(II), Cd(II), Cr(VI), Pb(II), and Zn(II) were subjected to biosorption at 10–250 mg/kg concentrations along with pH 5–8. The results showed that the preference of the organism for the five metals under study was in the order Pb(II) > Zn(II) > Cd(II) > Cu(II) > Cr(VI) at pH 6.5 under multimetal condition. The study also indicates that the metal interaction pattern in multimetal interaction is a property of their ionic radii. The response surface methodology clearly explains the effect of interaction of heavy metals on the accumulation potential of the organism using three-dimensional response plots. The present work suggests that the fungus Galerina vittiformis could be employed as a low-cost metal removal agent from heavy metal–polluted soil.     

Sources and Contamination of Heavy Metals in Sediments of Kabul River: The Role of Organic Matter in Metals Retention and Accumulation

In this study, sediment samples were collected from Kabul River (Pakistan) and analyzed for heavy metals including zinc (Zn), cadmium (Cd), chromium (Cr), nickel (Ni) and lead (Pb). The physico-chemical characteristics were also determined which are known to influence the metal accumulation within the sediment matrix. Heavy metal concentrations (mg kg^?1, dry weight basis) in the sediment were in the order of Zn > Cr > Ni > Pb > Cd. Heavy metal concentrations were found in moderately polluted category set by U. S. Environmental Protection Agency (USEPA). However, Cr and Ni concentrations exceeded the screening levels at the sites where a larger volume of industrial effluents enter into Kabul River. Higher concentrations of almost all the tested metals were detected at locations of greater industrial and sewage entry points. Sediment organic matter (OM) exhibited strong correlation with Pb (R² = 0.80), Ni (R² = 0.67) and Zn (R² = 0.46), indicating that OM plays a significant role in metal retention and accumulation. The findings of this study showed that Kabul River is reasonably contaminated with selected heavy metals released from anthropogenic sources. In the study area, sewage discharge was the major source of heavy metals including Zn and Pb, which were observed at locations where sewage effluents enter into the river.     

Concentration and ecological risk of heavy metal in street dusts of Eslamshahr,Iran

This study was done to evaluate heavy metal concentrations in street dust samples, to compare measured concentrations in samples to background concentrations in order to make evaluations for pollution indices, and to describe the quality of street dust in the studied area in relation to pollution. A total of 30 cumulative samples were collected from the streets of Eslamshahr City. Concentrations of heavy metals were determined using an Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). Results determined mean concentrations (mg/kg) of the heavy metals Cd, Cr, Cu, Ni, Pb, and Zn, in collected samples of street dust as 0.34, 35.1, 239, 42.4, 71.3, and 573, respectively. I_geo values for Cd and Cr, Cu, Ni, Pb, and Zn showed level of moderately polluted, unpolluted, moderately to strongly polluted, unpolluted, moderately polluted and moderately to strongly polluted, respectively. The pattern of total metal concentrations in the studied area was ranked as follows: Zn and Cu>Pb>Cd>Ni>Cr. The highest values for the monomial potential ecological risk (E_r) were observed for Cd (114). The mean level of RI for the studied soil samples was 192 (91.3–244), which is classed as presenting a strong potential ecological risk.     

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.     

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.     

Health risks of heavy metals to the general public in Hengyang,China, via consumption of rice

This investigation was conducted to survey the levels of cadmium (Cd), lead (Pb), chromium (Cr), copper (Cu), zinc (Zn), and manganese (Mn) in polished rice collected at supermarkets located in Hengyang, China. The surveyed rice samples were grouped according to their production areas into four different groups—Hunan, Jiangxi, Jilin, and Thailand. The data showed that the highest means of Cd, Pb, Cr, Cu, Zn, and Mn contents were in rice samples produced from Hunan (0.215 mg/kg), Thailand (0.537 mg/kg), Hunan (0.348 mg/kg), Jiangxi (2.472 mg/kg), Thailand (17.259 mg/kg), and Jinlin (9.326 mg/kg), respectively. Average daily intake dose for the six elements through consumption of rice was lower than the oral reference dose. Although the hazard quotient values for all six elements were <1.0, hazard index values in all the production areas (except Thailand) were >1.0, and cancer risk (CR) and total CR values were >10^?4, respectively. Certainly, there are inherent limitations for these health risk values, including actual ingestion rate, exposure duration, and bioavailability of heavy metals. These results indicate that long-term heavy metal exposure by consumption of rice in Hengyang could pose both potential non-carcinogenic and carcinogenic health risks to the local residents.     

Assessment of metals in agricultural soil of surrounding areas of Urmia Lake,northwest Iran: A preliminary ecological risk assessment and source identification

The aim of this study was to quantify the levels of toxic heavy metals and sodium in topsoil of farmlands around the Urmia Lake. A total of 96 topsoil samples were collected, pre-treated, and analyzed for metals using ICP-AES.

Median concentrations of As, Cd, Cu, Ni, Pb, Zn, and Na in sampling sites were 5, 0.26, 30, 40, 13, 84, and 251 mg/kg, respectively. The enrichment factor, geoaccumulation index, and contamination factor of the metals ranked them in the order of: Na > Pb > Cu > As > Cd > Zn > Ni, indicating minor contamination for them except Na and Pb with moderate contamination. Furthermore, the spatial analysis indicated that Cd, Cu, Pb, Ni, and Zn had similar distribution patterns in the north and northwest lands of the lake. Principal component analysis revealed anthropogenic sources for Cd, Cu, Ni, Pb, and Zn in the soil, whereas, sources of As and Na were most likely related to the dust emitting from the dried bed of Urmia Lake and from a cement industry. Potential ecological risk index in 7% of the sampling sites was at serious or considerable pollution level, and Cd and Pb were identified as the main pollutants.