Accumulation of metals and metalloids in radish (Raphanus sativus L.) and spinach (Spinacea oleracea L.) irrigated with domestic wastewater in the peri-urban areas of Khushab City,Pakistan

Accumulation of different metals and metalloids was assessed in two vegetables radish (Raphanus sativus L.) and spinach (Spinacea oleracea L.) irrigated with domestic wastewater in the peri-urban areas of Khushab City, Pakistan. In general, the metal and metalloid concentrations in radish and spinach were higher at site-II treated with sewage water than those found at site-I treated with canal water. In case of radish at both sites the levels of metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Cd, and Pb) were below the permissible level except those of Mn, Ni, Mo, Cd, and Pb. At both sites, the transfer factor ranged from 0.047–228.3 mg kg^?1 with Cr having the highest transfer factor. The metal pollution index in soil was in the following order: As > Fe > Ni > Zn > Cd > Mo > Se > Co > Pb > Mn > Cr > Cu, respectively. While in case of spinach at both sites, the concentrations of metals and metalloids in vegetable samples irrigated with canal and sewage water were observed below the permissible level except Mn, Ni, Zn, Mo, and Pb. At both sites, the transfer factor ranged from 0.038–245.4 mg kg^?1 with Cr having the highest transfer factor. The metal pollution index in soil was in the following order: Cd > Ni > Co > Se > Mn > Zn > Mo > Pb > Fe > Cr > As > Cu, respectively.     

X-ray Fluorescence (XRF) Analysis of Soil Heavy Metal Pollution from an Industrial Area in Kumasi,Ghana

Knowledge of soil heavy metal concentration is very important for assessing the purity and quality of the soil in an environment. The concentrations of nine heavy metals (NHM), Zn, Pb, Cr, Cu, Co, Ni, Cd, Hg, and As, from the near-surface soils (～ 0–15 cm) from an industrial cluster in Kumasi, Ghana, were qualitatively and quantitatively measured and analyzed using X-ray fluorescence (XRF) spectroscopy analysis. The sources of these NHM were mainly anthropogenic as a result of the indiscriminate industrial waste disposal. In all, a total of about 100 soil samples were taken from six sampling sites, four of which were industrial and the remaining two residential. Forty soil samples out of the total number were carefully selected for elemental analyses and the mean heavy metal concentrations were calculated using statistical methods. The results from locations of high industrial impact showed that the mean concentrations of the NHM present in the soil were in the order of Zn (189.2?908.6 mgkg^?1), Pb (133.7?571.3 mgkg^?1), Cr (91.3?545.8 mgkg^?1), Cu (62.9?334.6 mgkg^?1), Co (38.6?81.9 mgkg^?1), Ni (12.4?30.9 mgkg^?1), Cd (6.9?13.2 mgkg^?1), Hg (5.5?10.4 mg kg^?1), and As (2.3?18.6 mgkg^?1). Apart from Ni and As, all the heavy metals recorded concentrations that ranged from 10?900% higher than their respective threshold limit values (TLVs). Heavy metal concentrations from the residential sites were comparatively far lower with only Cr, Cd, and Hg registering concentrations between 65?250% above their TLVs. The cluster with its residential communities is at a serious risk of soil heavy metal toxicity and awareness to this needs to be created as such.     

Concentrations and ecological risks of metals in surface sediments of some coastal creeks in the Niger Delta,Nigeria

The concentrations of nine metals were measured by atomic absorption spectrophotometry in surface sediments of three coastal creeks, namely, the Ifie, Egbokodo and Ubeji creeks, in the Niger Delta of Nigeria, from August 2012 to January 2013. The aim of the study was to provide information on the spatial and seasonal distribution patterns, degree of contamination, and ecological risks of metals in these sediments. The mean concentrations of the nine metals in these creek sediments ranged from 0.30 to 3.20?mg kg^?1 Cd; 10.7 to 24.7?mg kg^?1 Pb, 125 to 466?mg kg^?1 Cr; 3.1.10 to 14.9?mg kg^?1 Cu; 4.7 to 14.3?mg kg^?1 Co; 61.1 to 115?mg kg^?1 Ni; 106 to 183?mg kg^?1 Mn; 52.0 to 170?mg kg^?1 Zn and 5 469 to 20 639?mg kg^?1 Fe. In general, the metal concentrations were higher in the dry season than the wet season, except for Cr. The concentrations of Cd, Cr, Ni and Zn were above their regulatory control limits in sediment as specified by the Nigerian Regulatory Authority and Cd was identified as the main ecological risk factor. The enrichment factors for the studied metals followed the order: Cd > Cr > Ni > Zn > Pb > Co > Mn > Cu. The average multiple pollution index values indicated that these sediments were severely polluted with significant inputs from Cd, Ni and Cr.     

Toxic and Essential Mineral Elements Content of Black Tea Leaves and Their Tea Infusions Consumed in Iran

The metal contents of eleven black tea samples, four cultivated in Iran and seven imported, and their tea infusions were determined. Twelve elements consisting toxic metals (Al, As, Pb, Cr, Cd, and Ni) and essential mineral elements (Fe, Zn, Cu, Mn, Ca, and Mg) were analyzed using inductively coupled plasma atomic emission spectroscopy (ICP-AES). Al, Ca, Mg, and Mn ranged in black tea leaves at mg g⁻¹ levels, while Cr, Fe, Ni, Cu, Zn were at μg g⁻¹ levels. Analysis of variance showed no statistically significant differences among most elements determined in cultivated and imported black teas in Iran except for Ni and Cu. The extraction efficiency of each element into tea infusions was evaluated. The solubility of measured metals in infusion extracts varied widely and ranged from 0 to 59.3%. Among the studied elements, Cr, Pb, and Cd showed the lowest rates of solubility and Ni had the highest rates of solubility. The amount of toxic metals and essential mineral elements that one may take up through consumption of black tea infusion was estimated. The amount of realizing each element into tea infusions and acceptable daily intake, for safety consumption of black tea, was compared.     

Impact of Land-Use Patterns on Chemical Properties of Trace Elements in Soils of Rural,Semi-Urban,and Urban Zones of the Niger Delta,Nigeria

The study of the concentrations of Cr, Zn, Cd, Pb, Ni, and Cu in soils under different land uses in rural, semi-urban, and urban zones in the Niger Delta was carried out with a view to providing information on the effects of the different land uses on the concentrations of trace elements in soils. Our results indicate significant variability in concentrations of these metals in soils under different land uses in rural, semi-urban, and urban zones. The maximum concentrations of metals in the examined soil samples were 707.5 mg.kg^?1, 161.0 mg.kg^?1, 2.6 mg.kg^?1, 59.6 mg.kg^?1, 1061.3 mg.kg^?1, and 189.2 mg.kg^?1 for Cr, Zn, Cd, Pb, Ni, and Cu, respectively. In the rural zone, the cassava processing mill is a potent source of Ni, Cr, Cu, and Zn while agricultural activities are a source of Cd, and automobile emissions and the use of lead oxide batteries constitute the major sources of Pb. In the urban zone, soils around the wood processing mill showed elevated concentrations of Cu, Cr, Zn, and Ni, while soils around automobile mechanic works and motor parks showed elevated levels of Pb. Elevated Cd concentrations were observed in soils under the following land uses: urban motor park, playground, welding and fabrication sheds, and metallic scrap dump. The contamination/pollution index of metals in the soil follows the order: Ni > Cd > Cr > Zn > Cu > Pb. The multiple pollution index of metals at different sites were greater than 1, indicating that these soils fit into “slight pollution” to “excessive pollution” ranges with significant contributions from Cr, Zn, Cd, Ni, and Cu.     

Mitigation of Heavy Metal Contamination in Soil via Successive Pig Slurry Application

This study evaluates heavy metal removal associated with phytomass management in a Typic Hapludox after three applications of pig slurry. Like humic acids in pig slurry were characterized through physics and chemical spectroscopy technics. Heavy metal levels were determined in ration that was offered to pigs, anaerobically digested pig slurry, and plant tissues from pig slurry-fertilized black oat (Avena strigosa Schreb.) and ryegrass (Lolium multiflorum Lam.) intercrop. Soil contamination was evaluated by the pseudo-total heavy metal levels in six soil layers and the bioavailable levels in the top soil layer. Results indicate that the ration is the origin of heavy metals in the pig slurry. The approximate levels in the ration were as follows (mg kg^?1): Cu 23.9, Zn 92.02, 153.15, Mn 30.98, Ni 0.23, Pb 10.75, Cr 0.34, Co 0.08, and Cd 0.05. The approximate levels of these metals in the pig slurry were as follows (mg kg^?1): Cu 71.08, Zn 345.67, Fe 83.02, Mn 81.71, Ni 1.13, Pb 4.35, Co 0.28, and Cd 0.16. Like humic acids contained 55% aliphatic chains, 14% oxygenated aliphatic chains, and 15% carboxyls, demonstrating their high capacity for interaction with heavy metals by forming soluble complexes. Soil contamination was indicated by the accumulation of heavy metals in the six soil layers in relation to the applied pig slurry dose (ranged as follows (mg kg^?1): Cu 110 to 150, Zn 50 to 120, Ni 20 to 40, and Pb 12 to 16) and as bioavailable forms (levels ranged as follows (mg kg^?1): Cu < 1, Zn 1.0–1.5, Ni 0.1–1.5, and Pb 1.9–6.3). The positive correlation between heavy metal accumulation in the plants and soil bioavailable heavy metal levels and the lowest heavy metal levels under higher intensity of phytomass removal demonstrate the ability of phytomass management to reduce soil contamination.     

Evaluation and Potential Health Hazard of Selected Metals in Water,Sediments, and Fish from the Gomti River

The health hazard associated with the consumption of fish from the Gomti River in India, contaminated with the heavy metals Cr, Cu, Mn, Ni, Pb, and Zn was assessed in terms of target hazard quotients (THQs). The concentrations of metals (mg kg^?1, wet weight basis) in the muscle tissues of different fish species Mastacembelus puncalus, Clupisona garua, Cyrinous carpio, Botia lochachata, Channa punctatus, Heteropneustise fossilis, Puntius sofore, and Clarious batrachus ranged as follows: Cr (2.2–21.4), Cu (0.3–14.3), Mn (2.3–5.5), Ni (0.5–10.9), Pb (1.0–3.9), and Zn (12.3–46.9). The accumulation of metals in fish muscle tissue was in the order: Zn > Cr > Ni > Mn > Cu > Pb. THQs indicated a potential health hazard to children due to the consumption of fish contaminated with Ni and Pb; their THQs were greater than 1 for almost all fish species except for Ni in C. garua (THQ, 0.07) and C. carpio (THQ, 0.90). For adults, insignificant health hazard was associated with THQs less than 1 for all metals in the different fish species, but long-term exposure to these metals and subsequent bioaccumulation in the body may require additional investigation.     

Phytoremediation Potential of Weeds in Heavy Metal Contaminated Soils of the Bassa Industrial Zone of Douala,Cameroon

Phytoremediation is a promising option for reclaiming soils contaminated with toxic metals, using plants with high potentials for extraction, stabilization and hyperaccumulation. This study was conducted in Cameroon, at the Bassa Industrial Zone of Douala in 2011, to assess the total content of 19 heavy metals and 5 other elements in soils and phytoremediation potential of 12 weeds. Partial extraction was carried out in soil, plant root and shoot samples. Phytoremediation potential was evaluated in terms of the Biological Concentration Factor, Translocation Factor and Biological Accumulation Coefficient. The detectable content of the heavy metals in soils was Cu:70–179, Pb:8–130, Zn:200–971, Ni:74–296, Co:31–90, Mn:1983–4139, V:165–383, Cr:42–1054, Ba:26–239, Sc:21–56, Al:6.11–9.84, Th:7–22, Sr:30–190, La:52–115, Zr:111–341, Y:10–49, Nb:90–172 in mg kg^?1, and Ti:2.73–4.09 and Fe:12–16.24 in wt%. The contamination index revealed that the soils were slightly to heavily contaminated while the geoaccumulation index showed that the soils ranged from unpolluted to highly polluted. The concentration of heavy metals was ranked as Zn > Ni > Cu > V > Mn > Sc > Co > Pb and Cr in the roots and Mn > Zn > Ni > Cu > Sc > Co > V > Pb > Cr > Fe in the shoots. Dissotis rotundifolia and Kyllinga erecta had phytoextraction potentials for Pb and Paspalum orbiculare for Fe. Eleusine indica and K. erecta had phytostabilisation potential for soils contaminated with Cu and Pb, respectively.     

Assessment of Hazardous and Essential Elements in a Food Crop Irrigated with Municipal Sewage Water: Risk Appraisal for Public Health

To assess the impact of sewage water on metal accretion in selected diverse varieties of wheat (i.e., Lasani-2008, ARRI-10, Faisalabad-83, Punjab-85, Aas-2010, and Sehar-2006), their seeds were sown in pots containing soil. The results showed that the concentration of heavy metals in grains from the wheat plants supplied with sewage water was considerably higher than the plants supplied with canal irrigation water (control). In canal water irrigated wheat grains the metal concentrations (mg/kg) ranged from 2.20–3.5 for Cu, 12.50–32.4 for Zn, 22.45–35.22 for Mn, 0.05–0.15 for Pb, 0.012–0.029 for Cd, 2.5–5.3 for Ni, 18.16–29.63 for Fe, and 0.90–3.64 for Cr in different wheat varieties, whereas the wheat grains raised from sewage water, had metal concentrations (mg/kg): 3.8–5.30 for Cu, 29.60–40.50 for Zn, 32.9–50.40 for Mn, 1.14–7.50 for Pb, 0.26–0.42 for Cd, 3.90–7.55 for Ni, 32.21–40.35 for Fe, and 2.88–7.84 for Cr. Since these metals bioaccumulate in wheat grains with unremitting use of metal-enriched wastewater, care has to be taken for irrigating wheat plants with household wastewater for a longer time, particularly in those soils where this crop is grown regularly.     

Human health risk assessment of trace elements in shallow groundwater of the Linhuan coal-mining district,Northern Anhui Province,China

Enrichment of trace elements in groundwater poses considerable risks to human health. The concentrations of seven trace elements (Cr, Mn, Ni, Cu, Zn, Cd, and Pb) in 34 samples of shallow groundwater from the study area were estimated. We assessed the concentrations of the trace elements and health risks with statistical analysis and the US Environment Protection Agency (USEPA) model. The results showed that the mean concentrations of trace elements decreased as follows: Mn > Zn > Ni > Cr > Cu > Cd > Pb. Apart from Mn at one sampling point, the concentrations of all trace elements were below the guideline values of the World Health Organization for drinking water. Correlation and cluster analysis indicated that the trace elements fell into groups, with Ni and Cu in one group, and Mn, Zn, and Cd in another, which suggested that the trace elements grouped together had similar sources. The total non-carcinogenic risk values ranged from 8.52 × 10^?4 to 1.27 × 10^?1. The total carcinogenic risk caused by Cr and Cd averaged 1.62 × 10^?6, which exceeded the acceptable level of 1 × 10^?6 recommended by the USEPA. The carcinogenic risk of Cr accounted for 75.93% of R_total.     

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.     

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.     

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.     

Characterization and human health risk assessment of trace metal in PM10 in Bac Giang,short-term study in a developing province in Vietnam

Abstract

This study investigated the airborne concentration of PM₁₀ and 20 trace elements (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Na, Pb, Ti, V, Zn) in residential, industry, traffic road, coal mining, thermal power plant area of Bac Giang province. The average PM₁₀ concentration was highest at coal site, followed by traffic 1 sites, industrial sites and traffic 2 sites, the residential sites, and lowest at the power plant site located in mountain area. While Al, Ca, Fe, K, Mg, Na were the most abundant elements in all sampling sites, accounting for 73–96% of total obtained elements, the concentration of As, Cd, Cr, Cu, Mn, Ni, Pb, V, and Zn occupied from 2.9 to 23.2%. Noticeably, the concentrations of Cd were from 7 to 65 times higher than the concentration limit for Cd (0.1?ng/m³) according the World Health Organization (WHO). Although, the Hazard Index (HI values) of all metals were found to be within the safe level for both children and adults, the Carcinogenic Risk (CR) of Cr and As in all sites were closed to the acceptable levels for children, implying a potential carcinogenic risks of these metals.     

Screening of Trace Metals in the Plasma of Breast Cancer Patients in Comparison with a Healthy Population

The plasmas of breast cancer patients and healthy donors were analyzed for selected trace metals by a flame atomic absorption spectrophotometric method. In the plasma of breast cancer patients, mean concentrations of macronutrients/essential metals, Na, K, Ca, Mg, Fe, and Zn were 3584, 197.0, 30.80, 6.740, 5.266, and 6.170 ppm, respectively, while the mean metal levels in the plasma of healthy donors were 3908, 151.0, 72.40, 17.70, 6.613, and 2.461 ppm, respectively. Average concentrations of Cd, Cr, Cu, Mn, Ni, Pb, Sb, Sr, and Zn were noted to be significantly higher in the plasma of breast cancer patients compared with healthy donors. Very strong mutual correlations (r > 0.70) in the plasma of breast cancer patients were observed between Cd–Pb, Cr–Li, Li–K, Li–Cd, K–Cr, Li–Pb, Cr–Co, Cu–Ni, Co–K, Cd–K, and K–Pb, whereas, Al–Cr, Ca–Zn, Cd–Sb, Cd–Zn, Ca–Mg, Fe–Zn, and Na–Mn exhibited strong relationships (r > 0.60) in the plasma of healthy donors. The cluster analysis revealed considerably different apportionment of trace metals in the two groups of donors. The average metal concentrations of different age groups of the two donor categories were also evaluated, which showed the build-up of Al, Cd, Co, Cr, Mn, Li, Pb, Sb, and Zn in the plasma of breast cancer patients. The role of some trace metals in carcinogenesis is also discussed. The study indicated appreciably different patterns of metal distribution and correlation in the plasma of breast cancer patients in comparison with the healthy population.     

Geochemical distribution of heavy metals in sediments from sewage fed fish ponds from Kolkata Wetlands,India

Abstract

Kolkata wetlands are the largest sewage fed wetlands in the world. They have been used for aquaculture since 1960. Geochemical distribution of heavy metals (Cr, Cu, Mn, Fe, Zn, Pb, Ni and Al) has been studied in surface sediments using single and sequential extractions techniques. The metal concentrations in sediments were in the following order: Fe>Al> Mn>Zn>Cu> Pb>Cr> Ni, and the average concentrations were 29 μg g^?1, 54 μg g^?1, 328 μg g^?1, 32747 μg g^?1, 169 μg g^?1, 38 μg g^?1, 25 μg g^?1 and 23371 μg g^?1 dry weights for Cr, Cu, Mn, Fe, Zn, Pb, Ni and Al, respectively. Water-soluble percentages of the trace elements are quite low (<0.01–3.75%) but in the presence of chelating agents in the sediments increase the bioavailability of trace elements (2–58%). About 40% of trace elements are in the stable form as a residual fraction of the sediment and more than 50% (nonresidual fraction) metal contamination of the Kolkata wetland sediments were from anthropogenic inputs. The contamination risks of Cr, Mn, Zn, Pb, and Ni are high as their potential availabilities are 70.96%, 58.01%, 63.13%, 55.62%, and 52.15% respectively. The mean concentration of most of the heavy metals in sediments does not exceed the recommended reference values. Zinc and lead concentrations were greater than background level and Interim Sediment Quality Guidelines but lower than Probable Effect Level. Therefore a regular program for monitoring the distribution of heavy metals in water, sediments and biota should be imposed on sewage fed fish ponds of the Kolkata wetland ecosystem.     

Heavy metals in water,sediments, fish and plants of river Hindon,U.P., India

We analysed the concentrations of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn in the water, sediments, fish and plants of the River Hindon, U.P., India, at seven sampling stations, in the year 1982. Considerable variation in concentration between water, sediments, fish and plants were noted. The concentration in the water was in the order Fe > Zn > Cr > Mn > Cu > Pb > Ni > Co > Cd, in the sediments, Fe > Mn > Zn > Ni > Cr > - Co > Cu > Pb > Cd; in a fish (Heteropnuestes fossilis) Fe > Zn > Mn > Pb > Ni > Co > Cu > Cd > Cr, and in a plant (Eicchornia crassipes) Fe > Mn > Zn > Ni > Cu > Cr > Pb > Co > Cd.     

Total concentrations and fractionation of heavy metals in road-deposited sediments collected from different land use zones in a large city (Nanjing), China

Abstract

In order to investigate heavy metal contamination in an urban environment during urbanization and economic development, 35 road-deposited sediment samples were collected from seven different land-use zones (commercial, residential, traffic, scenic park, educational, industrial and peri-urban) in Nanjing, a large city in P.R. China. The ranges of total metal concentrations found were: 28.7–272 mg kg^?1 for Cu; 24.8–268 mg kg^?1 for Ni; 37.3–204 mg kg^?1 for Pb; 140–798 mg kg^?1 for Zn; 0.44–2.19mg kg^?1 for Cd; and 60.6–250 mg kg^?1 for Cr. Metal fractionation was carried out using a modified three-step European Bureau of References (BCR) sequential extraction procedure. Cadmium and Zn were found predominantly associated with the acid extractable fractions; Ni and Cr were dominant in the residual fraction; Pb was predominantly associated with the residual and reducible fractions; Cu was dominant in the oxidizable and residual metal fractions. Based on the sum of the acid-extractable, reducible, and oxidizable fractions, Cd, Zn and Pb are potentially the most toxic metals in the road-deposited sediment in Nanjing. No significant differences, except for Zn, were found in the metal fractionation pattern for Cu, Ni, Pb, Cd, and Cr in different land use zones.     

Heavy metal contamination in vegetables grown around peri-urban and urban-industrial clusters in Ghaziabad,India

Heavy metal contamination of agricultural soils resulting from rapid industrialization and urbanization is of great concern because of potential health risk due to dietary intake of contaminated vegetables. The present study aims to evaluate the status of heavy metals contamination of agricultural soils and food crops around an urban-industrial region in India. Transfer factor values of Cu, Cr, Pb, Cd, Zn, and Ni from soil to vegetable was estimated. The mean heavy metal concentrations (mg/kg) in agricultural soils (Cu: 17.8, Cr: 27.3, Pb: 29.8, Cd: 0.43, Zn: 87, Mn: 306.6, Fe: 16984, and Ni: 53.8) were within allowable concentrations for Indian agricultural soil. The concentrations of Pb, Cd, Zn, and Ni in crops/vegetables exceeded the World Health Organization/Food and Agriculture Organization safe limits. Relative orders of transfer of metals from soil to edible parts of the crops/vegetables were Cd > Pb > Ni > Zn > Cu > Cr. The enrichment factors of heavy metals in soil indicated minor to moderately severe enrichment for Pb, Cd, and Ni; minor to moderate enrichment for Zn; no enrichment to minor enrichment for Mn; and no enrichment to moderate enrichment for Cu at different sites. Ecological risk index of soil showed considerable contamination in one of the wastewater irrigated sites.     

Size dependent metal concentrations in two marine gastropod species

The effect of size on the accumulation of Cd, Cr, Cu, Mn, Ni, Fe and Zn in the muscle and viscera of the gastropodsMonodonta turbinata andCerithium vulgatum was investigated. The concentration of the essential metals Cr, Mn and Ni and the non-essential metal Cd decreased with increasing size in both of the species and tissues. The concentration of the essential metals Cu, Fe and Zn, showed a less constant relation with size.