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.     

Mineral and chemical characteristics,textural parameters,and the mobility of the selected elements of flotation waste,originating from the Polish copper-mining industry

This article discusses the mineralogy and geochemical characteristics of the fresh copper-flotation waste samples. The mobility of As, Cd, Cr, Cu, Ni, Pb, Tl, Zn was investigated by leaching tests. The main mineral phases identified concerned dolomite, quartz, clay minerals, feldspars, and copper-bearing minerals. Chemically, CaO and silica were dominating, along with a significant concentration of precious (Cu), refractory (Cr, Ti, V, Zr), and toxic (As, Cd, Pb) metals. Elements were bound mainly to the residual fraction and sulphides in the following order: Pb > Cu ≈ Tl > As ≈ Zn > Ni ≈ Cr > Cd. The metal mobility patterns expressed as a percentage of total concentrations, were as follows: Cd (42%) > Cr (26%)> Ni (24%) > Zn (23%) > As (22%) > Tl (20%) > Cu (18%) > Pb (2%). Those constituents were released earlier in lower pH values, although Cu, Cr, and Pb were also released in higher alkaline pH values. However, Zn release was not dependent on pH. When L/S values decreased, elements like As, Cr, Cu, Pb, and Tl were released. That process caused decrease of Cd, Ni, and Zn release.     

Assessment of Heavy Metal Enrichment,Bioavailability, and Controlling Factors in Sediments of Taihu Lake,China

Heavy metal distribution, bioavailability, and ecological risk in the surface sediment of Taihu Lake were evaluated. Samples were collected from eight representative sites in September 2011 and February 2012. In the surface sediment, average metal contents were in the order of Cr > Zn > Ni > Pb > Cu. Spatially, Zhushan Bay maintained higher Cu, Ni, and Zn contents and Xiaomeikou maintained higher Cr and Pb contents than other sites. Spatial and temporal variation were observed in the bioavailable metals determined by acid-soluble fraction of BCR extraction. The labile metals in Zhushan Bay and Xiaomeikou were quantified by diffusive gradients in thin films (DGT) and DGT-labile concentrations of Zn, Ni, Cu, Pb, and Cd were in descending order, indicating the inconsistence of labile concentrations of different heavy metals with the total metal contents and that the toxic effect of Cd in sediment should be given attention. The ecological risk assessed by Hakanson potential ecological risk index showed that Zhushan Bay suffered the most serious pollution and should be given special attention. Bioavailability of metals should be taken into account during risk assessment for more accurate estimation.     

Arsenic and heavy metals health risk assessment through drinking water consumption in the Peshawar District,Pakistan

This study aimed to assess the drinking water quality and human potential health risk in Peshawar, which is the most populous district of Khyber Pakhtunkhwa Province, Pakistan. Water was randomly collected throughout Peshawar District (urban = 45 samples and rural = 29 samples). These samples were analyzed for heavy metal (As, Cd, Co, Cu, Cr, Hg, Ni, Pb, and Zn) concentrations using the atomic absorption spectrometer (Perkin Elmer, AAS-PEA-700). Heavy metal concentrations in drinking water revealed the highest pollution index (PI) values—17.80, 11.92, 7.50, and 5.70 for the Pb, Cr, Cd, and Ni, respectively. The contaminations of Cd and Pb were significantly higher (p < .05) than their maximum allowable limits set by the World Health Organization. Heavy metal contaminations in drinking water were evaluated for health risk assessment: the chronic risk or hazard quotient (HQ) and cancer risk. Results revealed that HQ values were >1 for the Cd and Pb, suggesting that the exposed human beings could be at chronic risk. Therefore, serious measures such as drinking water treatments and contamination controlling policies are needed to avoid the hazardous effects of toxic heavy metals.     

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.     

Heavy metal contamination and health risk assessment in soil-rice system near Xinqiao mine in Tongling city,Anhui province,China

In this study, paddy soil and rice grain samples were collected from the vicinity around the Xinqiao mine in Tongling, China to test for the presence of heavy metals (Cd, Ni, Cr, Cu, Zn, and Pb) in soil-rice system. Results indicated that the soil samples were primarily contaminated with Cd and Cu and followed with Zn and Pb. In rice grains, Cd, Cu, and Cr concentrations exceeded recommended guidelines. However, the regional distribution of heavy metals in rice grains and soil was inconsistent. The bioaccumulation factor of heavy metals in rice grains decreased in the order of Cd > Zn > Cu > Ni > Cr > Pb. The BAF was significantly positively correlated with TCLP-extractable metals and significantly negatively correlated with soil pH. However, the relationship between soil organic matter and the BAF in rice grains was complex. Health risk assessment through rice intake showed that hazard quotients of Cu and Cd were greater than 1 and could pose a considerable non-cancer health risk to adults and children; meanwhile, Cr, Ni, and Cd could pose an unacceptable cancer risk. The results indicated that the government must take measures to reduce heavy metal contents in paddy soil and rice.     

Effects of Municipal Sewage Sludge Doses on the Chlorophyll Contents and Heavy Metal Concentration of Sugar Beet (Beta vulgaris var. saccharifera)

The present study was conducted to assess the suitability of sewage sludge amendment (SSA) in soil for Beta vulgaris var. saccharifera (sugar beet) by evaluating the heavy metal accumulation and physiological responses of plants grown at a 10%, 25%, and 50% sewage sludge amendment rate. The sewage sludge amendment was modified by the physicochemical properties of soil, thus increasing the availability of heavy metals in the soil and consequently increasing accumulation in plant parts. Cd, Pb, Ni, and Cu concentrations in roots were significantly higher in plants grown at 25% as compared to 50% SSA; however, Cr and Zn concentration was higher at 50% than 25% SSA. The concentrations of heavy metal showed a trend of Zn > Ni > Cu > Cr > Pb > Cd in roots and Zn > Cu > Ni > Cr > Pb > Cd in leaves. The only instance in which the chlorophyll content did not increase after the sewage sludge treatments was 50%. There were approximately 1.12-fold differences between the control and 50% sewage sludge application for chlorophyll content. The sewage sludge amendment led to a significant increase in Pb, Cr, Cd, Cu, Zn, and Ni concentrations of the soil. The heavy metal accumulation in the soil after the treatments did not exceed the limits for the land application of sewage sludge recommended by the US Environmental Protection Agency (US EPA). The increased concentration of heavy metals in the soil due to the sewage sludge amendment led to increases in heavy metal uptake and the leaf and root concentrations of Ni, Zn, Cd, Cu, Cr, Pb, and Zn in plants as compared to those grown on unamended soil. More accumulation occurred in roots and leaves than in shoots for most of the heavy metals. The concentrations of Cd, Cr, and Pb were more than the permissible limits of national standards in the edible portion of sugar beet grown on different sewage sludge amendment ratios. The study concludes that the sewage sludge amendment in the soil for growing sugar beet may not be a good option due to risk of contamination of Cr, Pb, and Cd.     

Heavy Metal Contamination in Sediments and Floodplain Topsoils of the Lean River Catchment,China

Heavy metals (Cd, Ni, Cu, Pb, and Zn) and total sulfur (TS) in both surficial sediments and adjacent floodplain topsoils of the Lean River catchment are investigated to comprehend the effects of flooding on heavy metals in soils, the evolution of the quality of sediments, and transfer of sediment metals. The results show that concentrations of metals except for Ni in soils are significantly correlated with those in sediments. At most upstream or downstream locations, sediment metal concentrations are found comparable to those in soils (sed/soil≈1). For Cu at locations close to the Dexing Copper Mine (DCM), flooding brought Cu-poor clays into the floodplain soil system and this leads to sed/soil<1, while at locations adjacent to the Yinshan Lead-zinc Mine (YLM), suspended solids containing high concentrations of iron and magnesium oxide absorb large quantities of dissolved Cd, Pb, and Zn and deposit on the floodplain during flooding (sed/soil>1). In spite of an elevated Cu production of the DCM, a significant decrease in sediment Cu concentrations is found as compared to those 10 years ago. The decrease may be due to the elevated Cu ore utilizing efficiency and the use of a new modern tailing pool. At the location closest to the Yinshan Lead-zinc Mine (YLM), Pb and Zn concentrations increased in recent sediments. In the Lean River, metal contamination in sediments cannot reach the location 60 km downstream of their sources in 2005.     

Characterization of Heavy Metal Fractions in Agricultural Soils by Sequential Extraction Procedure: The Relationship Between Soil Properties and Heavy Metal Fractions

The present research was conducted to determine heavy metals in agricultural soils from Çanakkale, Turkey, using a sequential extraction procedure (acid soluble, reducible, oxidizable, and residual) as proposed by the Community Bureau of Reference (BCR) of the European Commission. Soil samples were taken from 12 different cultivated sites and analyzed for Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn concentrations. The results revealed an order of Mn > Cd > Pb > Co > Ni > Cu > Zn > Cr for the heavy metals based on the sum of the first three fractions (acid soluble + reducible + oxidizable). The relationships between soil properties and each metal fraction were identified through Pearsons's correlation analysis. Hierarchical cluster analysis was performed to determine the behaviors and similarities of metals in each fraction. While Mn, Pb, and Zn exhibited subjective behaviors in the acid-soluble fraction, Cd, Co, Cu, Cr, and Ni exhibited similar behaviors with each other.     

Solid-Phase Chemical Fractionation of Selected Trace Metals in Some Northern Kentucky Soils

The fractionation and distribution with depth of Cd, Cr, Cu, Ni, Pb, and Zn in 26 soils of Northern Kentucky were determined through a sequential extraction procedure in response to environmental concerns about increasing anthropogenic inputs in a fast-paced, urbanizing area. The selected sites have not received any biosolid- or industrial-waste applications. Average total concentrations per metal in soil profiles derived from alluvial, glacial till, and residual materials ranged from 0.43 to 56.00 mg kg^?1 in the sequence Zn > Ni > Pb > Cr > Cu > Cd, suggesting relatively small anthropogenic inputs. The distribution of Cu, Cr, Ni, and Zn increased with soil depth, whereas Cd and Pb remained stable, indicating a strong geological or pedogenic influence. Residual forms were most important for the retention of Cu, Zn, and Ni. Cadmium and Pb exhibited a strong affinity for the Fe-Mn oxide fraction, while Cr showed the strongest association with the organic fraction. In terms of metal mobility and toxicity potential inferred from metal concentrations in labile fractions, Cd posed the greatest risk, followed by Cr ～ Pb > Ni > Zn > Cu. Soil pH, OM, and clay content were the most important parameters explaining the partitioning of metals in labile and residual fractions, emphasizing the importance of metal fractionation in soil management decisions. Alluvial soils generally contained the highest total and labile metal concentrations, suggesting potential metal enrichment through anthropogenic additions and depositional processes. These environments exhibit the highest risk for metal mobilization due to drastic changes in redox conditions, which can destabilize existing metal retention pools.     

Source analysis and health risk of heavy metals in the different seasons from Taizihe River,China

Twenty five water samples were collected along the Taizihe River, the concentration and health risks of Zn, Cu, Pb, Cr and Cd were detected and evaluated, and the pollution sources was analyzed through principal components analyses. The results indicated that the order of average concentration of heavy metals was follows: Pb > Cr > Cu > Zn and Cd. Among that, the concentrations of Zn, Cu and Cr were at the permissible levels, but Pb and Cd exceeded grade V standard at some sites. The concentrations of Zn and Cu in the wet season were significant higher than that in the dry season (p < 0.05), but the average concentrations of Pb, Cr and Cd were not significantly different in the two seasons (p > 0.05). The annual average risks of human health caused by Cd and Cr were 10⁻³/a and 10⁻⁴/a, respectively, which were higher than the recommended maximum acceptable risk level. The human health risk values of Zn, Pb and Cu were all concentrated at 10⁻⁸/a or 10⁻⁹/a levels, which did not exceed the recommended standard. On the whole, Cd and Cr were the main health risk pollutants of Taizihe River. Pollution sources of Pb was different from other heavy metals in wet and dry season, Cd and Cr were similar in the wet and dry season. The mainly pollution source of heavy metals was industry, especially mining, metal smelting and electroplating industry.     

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.     

Bioaccessibility of heavy metals in rapa whelk Rapana venosa (Valenciennes, 1846): Assessing human health risk using an in vitro digestion model

Instead of total metal concentration measurements in seafood, bioaccessibility is a more important parameter for human health risk assessment. Therefore, bioaccessibility of Cd, Cr, Cu, Mn, Ni, Pb, and Zn in the edible soft tissues of rapa whelk (Rapana venosa Valenciennes, 1846) collected along the southern Black Sea coast were investigated using an in vitro digestion model. Zn was detected at the highest concentration, whereas Ni was the lowest for total metal concentrations. Total Cd and Pb concentration in the tissues were found to be higher than maximum permissible limits set by European Commission. The bioaccessibility of metals in the tissues was found to be decreased in the order: Cu (77.11%) > Cd (70.13%) > Zn (64.52%) > Ni (61.27%) > Pb (50.53%) > Cr (43.41%) > Mn (22.59%). While significant positive linear regressions were observed between the total and bioaccessible concentrations for Mn, Pb, and Ni, significant negative linear regressions were found for Cd in the tissues (p < 0.05). The hazard quotients (HQ) calculated using bioaccessible heavy metal amount were detected lower than the limit value (HQ < 1), which may not pose a potential hazard to humans declared by US Environmental Protection Agency. However, the consumption of rapa whelk may cause a potential risk concerning human health for the Cd and Pb levels in case of increased serving sizes and portions.     

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.     

Heavy metal bioaccumulation by the organs of Phragmites australis (common reed) and their potential use as contamination indicators

The concentrations of heavy metals in the roots, rhizomes, stems and leaves of the aquatic macrophyte Phragmites australis (common reed), and in the corresponding water and sediment samples from the mouth area of the Imera Meridionale River (Sicily, Italy), were investigated to ascertain whether plant organs are characterized by differential accumulation, and to test the suitability of the various organs for heavy metal biomonitoring of water and soil. Heavy metals considered were Cd, Cr, Cu, Hg, Mn, Ni, Pb, Zn. Results showed that belowground organs were the primary areas of metal accumulation. In particular, metal concentrations in plant organs decreased in the order of root > rhizome ≥ leaf > stem. All four organs showed significant differences in concentration for Cr, Hg, Mn, Zn, thus suggesting low mobility from roots to rhizomes and to aboveground organs. Although the organs followed different decreasing trends of metal concentration, the trend Mn > Zn > Pb > Cu was found in each plant organ. Mn showed the highest concentrations in all organs whereas the lowest concentrations regarded Cd and Cr in the belowground and aboveground organs, respectively. The toxic threshold was exceeded by Cr in roots, rhizomes and leaves, Mn in roots and leaves, Ni in roots. The highest average concentrations were found as follows: Cd, Hg, Pb, Zn in root, Cr, Mn, Ni in sediment, Cu in water. Positive linear relationships were found between heavy metal concentrations in all plant organs and those in water and sediment, thus indicating the potential use of such organs for pollution monitoring of water and sediment. Advantages of using plant species as biomonitors, especially Phragmites australis, were also discussed.     

Heavy Metals (Cd,Cu, Ni,Pb, and Zn) Fractionation in River Sediments,Hamedan, Western Iran

Five heavy metals (Cd, Cu, Ni, Pb, and Zn) in river sediments from Abshineh River, Hamedan, western Iran, were fractionated by a sequential extraction procedure. Cu, Ni, Pb, and Zn existed in sediments mainly in residual fraction (mean 92%, 86%, 77%, and 65%, respectively), whereas Cd occurred mostly as organic matter (mean 41%) and exchangeable (mean 25%) fractions. The mean percent of mobile fraction of Cd, Cu, Ni, Pb, and Zn in contaminated sediments was 25, 13, 4, 24, and 10, respectively, which suggests that the mobility and bioavailability of the five metals in sediments probably decline in the following order: Cd = Pb > Cu > Zn > Ni. The metal levels were also evaluated according to the contamination factor, which revealed significant anthropogenic pollution of Cd and Pb.     

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.     

Bioaccessibility of Cd,Cr, Cu,Mn, Ni,Pb, and Zn in Mediterranean mussel (Mytilus galloprovincialis Lamarck, 1819) along the southeastern Black Sea coast

The adverse effect of seafood consumption on human health is related to the bioaccessibility in contrast with the total heavy metal level in the tissues. In this study, bioaccessibility of Cd, Cr, Cu, Mn, Ni, Pb, and Zn in Mediterranean mussel (Mytilus galloprovincialis Lamarck, 1819) edible soft tissues collected along the southern Black Sea coast were investigated using in vitro digestion model. Total Pb concentration in the tissues was found to be higher than the maximum permissible limits set by European Commission. The bioaccessibility of metals in the tissues was found to be decreased in the order: Ni (83.11%) > Cu (80.47%) > Zn (76.86%) > Cd (73.32%) > Mn (69.11%) > Pb (61.07%) > Cr (58.44%). While significant positive linear regression was observed between total and bioaccessible concentrations for Mn, Pb, and Ni, significant negative linear regression was found for Cd (p < .05). The hazard quotients (HQ) calculated using bioaccessible amount were detected lower than the limit (HQ <1), which may not pose a potential hazard to humans reported by US Environmental Protection Agency. In sum, mussel consumption from sampling sites may cause a potential risk concerning human health especially for Cd and Pb in case of increased portion sizes.     

Trace Element Level in Different Tissues of <Emphasis Type="Italic">Rutilus frisii kutum</Emphasis> Collected from Tajan River,Iran

Tajan River is among the most significant rivers of the Caspian Sea water basin. In this study, the concentration of Cr, Cu, Fe, Mn, Ni, Pb, Cd, and Zn were determined in brain, heart, liver, gill, bile, and muscle of Rutilus frisii kutum which has great economic value in the Mazandaran state. Trace element levels in fish samples were analyzed by means of atomic absorption spectrometry. Nearly all non-essential metals levels (Ni, Pb, Cd) detected in tissues were higher than limits for fish proposed by FAO/WHO, EU, and TFC. Generally, non-essential metals (Ni, Pb) were so much higher in muscle than the essential metals (Cu, Zn, and Mn) except Fe, which was higher than other metals in nearly all parts, except in gills. Fe distribution pattern in tissues was in order of heart > brain > liver > muscle > bile > gill. Distribution patterns of metal concentrations in the muscle of fish as a main edible part followed the sequence: Fe > Pb > Ni > Cu > Mn > Zn > Cd.     

Spatial distribution,contamination levels,sources, and potential health risk assessment of trace elements in street dusts of Urumqi city,NW China

Abstract

A total of 83 dust samples were collected from the streets of Urumqi city in NW China and analyzed for the concentrations of As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn elements. The spatial distribution, contamination levels, main sources, and potential health risks of these trace elements were determined based on geostatistical analysis, geo-accumulation index, multivariate analysis, and the health risk assessment model introduced by the USEPA, respectively. The obtained results indicate that the average concentrations of Cd, Cr, Cu, Hg, Ni, Pb, and Zn exceed the corresponding background values determined in Xinjiang soils by factors of 2.0, 1.35, 1.38, 8.24, 1.28, 2.09, and 3.26, respectively. The spatial distribution patterns of the nine trace elements in street dust were found to be substantially heterogeneous, and the contamination level decreased in the following order: Hg?>?Zn?>?Pb?>?Cd?>?Cr?>?Cu?>?As?>?Ni?>?Mn. Based on the identified concentrations, the collected dust samples were found to be moderately polluted by Hg, and not polluted by As, Cr, Cu, Mn, and Ni. The remaining elements, Cd, Pb, and Zn lie on the borderline between non-pollution and moderate pollution levels. Furthermore, it was shown that Mn and Zn in street dusts originate from both, natural and anthropogenic sources, while As, Cd, Cr, Cu, Hg, Ni, and Pb are mainly produced by anthropogenic sources. Overall, the carcinogenic and non-carcinogenic health risks of the analyzed elements, instigated primarily by oral ingestion of street dusts, were found to be within the acceptable range for both, children and adults. As and Cr are the main non-carcinogenic elements, whereas Cr is the major carcinogenic element among the investigated dust-bound metals in the study area.