Detection and Analysis of 12 Heavy Metals in Blood and Hair Sample from a General Population of Pearl River Delta Area

To detect the content of 12 heavy metals in blood and hair sample from a general population of Pearl River Delta area, and to analyze the influence of duration of residence, gender, age, smoking and drinking on the heavy metal content. Use inductively coupled plasma mass spectrometry to detect the content of 12 heavy metals lead (Pb), mercury (Hg), cadmium (Cd), aluminum (Al), arsenic (As), copper (Cu), chrome (Cr), manganese (Mn), nickel (Ni), zinc (Zn), tin (Sn) and antimony (Sb) in blood and hair samples of a total of 50 subjects from a general population, collected by multistage stratified cluster random sampling method. The geometric mean of heavy metal content in blood samples of general population (μg/L): blood aluminum 214.00; blood chrome 92.82; blood manganese 21.43; blood nickel 20.59; blood copper 0.67; blood zinc 11.50; blood arsenic 0.55; blood cadmium 2.45; blood tin 0.00; blood antimony 1.92; blood lead 158.84; and blood mercury 1.19. The geometric mean of heavy metal content in hair samples of general population (μg/g): hair aluminum is 84.65; hair chrome 0.00; hair manganese 2.44; hair nickel 0.61; hair copper 28.49; hair zinc 136.65; hair arsenic 0.75; hair cadmium 0.46; hair tin 1.04; hair antimony 0.05; hair lead 8.97; and hair mercury 0.69. Some heavy metals were correlated with duration of residence, gender, age, smoking and drinking. This was the first time that simultaneously detecting heavy metal content in blood and hair was used to analyze the internal heavy metal burden in resident population of Pearl River Delta area. These data can serve as reference for further research.     

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.     

Contamination and environmental risk assessment of heavy metals in marine sediments from Tahaddart estuary (NW of Morocco)

Abstract

The distribution, contamination status, and ecological risks of heavy metals in Tahaddart estuary were investigated. 24 surface sediment samples and two cores were collected and analyzed for major (Al and Fe), heavy metals (As, Cd, Cr, Cu, Ni, Pb, and Zn), and grain size composition. The heavy metals assessment was carried out using different environmental indices. The results indicated that the spatial distribution patterns of Al, Fe, and Zn were mainly determined by the distribution of the finer grained fraction (<63?μm) in the sediment. In contrast, As, Cd, Cr, Cu, Ni, and Pb concentrations were controlled by anthropogenic activities (vehicular traffic from Highway Bridge and thermal power plant). The distribution of heavy metals in sediment cores showed an upward enrichment in heavy metals with high concentration found in the uppermost may related to the increasing in human activities. The pollution indexes confirmed that the Tahaddart estuary sediment was considerably to high contaminated by heavy metals near to different anthropogenic inputs. Similarly, the potential ecological risk index and the biological risk index present 21% probability of toxicity posing potential risk to the aquatic organisms. These results provide basic information that can be used to protect and improve the quality of this ecosystem.     

Rhamnolipid biosurfactant-enhanced soil flushing for the removal of arsenic and heavy metals from mine tailings

Mine tailings containing high contents of arsenic and heavy metals are potential environmental contamination sources. Column experiments were conducted in this study to evaluate the feasibility of using a rhamnolipid biosurfactant (JBR425) to enhance the removal of arsenic and heavy metals from an oxidized mine tailings sample collected from Bathurst, Canada. Capillary electrophoresis (CE) analyses indicated that arsenate [As(V)] was the only extractable arsenic species in the mine tailings. The addition of rhamnolipids did not change the oxidation state of arsenic. It was found that a 0.1% rhamnolipid solution (initial pH adjusted to 11) could significantly enhance the removal of arsenic and heavy metals (i.e., Cu, Pb and Zn) simultaneously. The accumulative removal of arsenic, Cu, Pb and Zn reached 148, 74, 2379, and 259 mg/kg after a 70-pore-volume flushing, respectively. Moreover, the mobilization of arsenic and heavy metals by rhamnolipids was found to be positively correlated with that of Fe, and the mobilization of arsenic was also positively correlated to that of the heavy metals. The mobilization of co-existing metals, to some extent, might enhance arsenic mobilization in the presence of rhamnolipids by helping incorporate it into aqueous organic complexes or micelles through metal-bridging mechanisms.     

Cumulative Title Index

Abstract

Metal fractionation is a powerful tool for studying the mobility, bioavailability and toxicity of metals in sediments and soils. A seven-step sequential extraction technique was used to determine the potential mobility of selected heavy metals (Fe, Mn, Zn, Cu, Pb, Cd and Ni) in the sediments of Lake Naivasha. Results indicate that residual fraction was the most important phase for the elements Fe, Mn, Cu and Zn. However, Pb and Cd are highly enriched in the non-residual phases. Nickel on the other hand was distributed evenly between the non-residual and the residual fractions.

The total concentrations of the heavy metals suggested a decreasing order of iron ?> manganese ? zinc > nickel > copper ? lead > cadmium. However, the detailed sequential extraction data indicated an order of release or mobility of cadmium > lead ? nickel ? zinc > manganese > copper > iron. The high percentage of Cd and Pb in the mobile fractions suggests high bioavailability of these two elements in the study area and maybe a pointer to anthropogenic input of the two elements in the study area.     

Concentration of arsenic in groundwater,vegetables, human hair and nails in mining site in the Northern Thai Nguyen province,Vietnam: human exposure and risks assessment

This study was aimed to examine the risk of chronic arsenic (As) exposure for the residents living in Nui Phao, Thai Nguyen in the northern Vietnam. Groundwater, vegetables, human hair, and nail samples were collected from volunteers living in Nui Phao. The results revealed that 75% of the groundwater samples had As exceeding the World Health Organization (WHO) drinking water guideline of 10 µg L^?1. The result of As concentration for most of the vegetable samples was greater than the WHO/FAO safe (0.1?mg kg^?1). The result of hair and nail samples in this study showed that 3.5 and 20% of the samples had As concentration exceeding the level of As toxicity in hair and nails, respectively. The result of health risks indicated that the potential health risk of As contamination is greater for groundwater than vegetables. The total hazard quotient (HQ) value through vegetables ingestion and drinking water exceeded 1.0 suggesting potential health risk for local residents. The calculation of potential carcinogenic risk through both consumption of vegetables and drinking water was low cancer risk in adults. Other food sources and the exposure pathways are needed to exactly assess health risks in this area.     

Preliminary study on heavy metals contamination of soil using solid phase speciation and the influence on groundwater in Bozanta–Baia Mare Area,Romania

Abstract

A preliminary study on soil contamination with heavy metals and As based on solid phase speciation according to the Tessier scheme and the influence on groundwater in an area under anthropogenic influence (Bozanta-Baia Mare, Romania) was conducted. The partitioning of Al, As, Cd, Cu, Fe, Mn, Pb and Zn in five fractions is discussed in relation to soil characteristics, pH, organic matter content, mineralogical composition and distribution of the same elements in airborne particulate matter. The airborne particulate matter contains high quantities of As, Cd, Cu, Pb and Zn as exchangeable fraction. The sequential extraction carried out on soil samples revealed the main role of Fe-Mn oxides surface in the immobilization of metals. Organic matter has a specific role in complexation of Cu, Pb, As and Al, since high contents of these metals were recovered in the oxidizable fraction. Cadmium has a high selectivity for carbonate minerals. The amendment of soil with natural fertilizer increases the exchangeable fraction of metals with the highest toxicity. The available fraction for plants (exchangeable + carbonate-bound species) exceeded the alert values in soil, therefore the continuous monitoring of the area is necessary. The soil is unsuitable for agricultural use due to high contamination on surface with toxic elements resulted from anthropogenic activities. Groundwater is contaminated with very toxic elements (As, Cd and Pb) but also with Cu, Mn and Zn and is unsuitable as supply for drinking water.     

Study of the age and sex dependence of trace elements in hair by correspondence analysis

The aim of the study was to examine the potential of multidimensional analysis, and in particular of correspondence analysis (CA), in bringing to light the influence of sex and age on trace element (TE) concentrations in hair from an unselected French population. Sixteen elements (S, Hg, Se, Zn, Pb, Cd, Ni, Co, Mn, Fe, Cr, Mg, Al, Ca, Cu, Ag) were assayed by inductively coupled argon plasma (ICAP) emission specrroscopy in the scalp hair of 135 men and 346 women. In spite of the high background noise, CA was able to reveal the differing patterns in males and females. For instance, in this population, higher relative levels of the essential elements, Ca, Mg, Zn, and Cu, but also of Ag, characterized women’s hair, whereas higher relative levels of the heavy metals, Fe and Pb, were associated with men’s hair. Al and Ag were unexplainedly high in the hair of the youngest members of the population. The Cu and Co of youth seemed to give way to a predominance of Zn in maturity. The hair of individuals in their forties tended to be richest in Ca and Mg, but these elements decreased with advancing age. Heavy metals (Hg, Pb, Fe) accumulated with age, whereas Se, Mn, and Cr seemed independent of age. CA is manifestly a very useful tool for revealing underlying dimensions in complex dynamic systems and unsuspected relationships among variables. Clearly, the significance of the high Al and Ag contents in the hair of certain members of the population, especially of the very young, needs to be investigated from both physiological and toxicological aspects.     

Fractionation,mobility and multivariate statistical evaluation of metals in marine sediments of Cape Town Harbour,South Africa

Abstract

Distribution of possible chemical forms of Al, Si, Sn, Pb, Zn, Fe, Hg, Cd and Cu in marine sediments of Cape Town harbour was investigated using a modified Tessier’s sequential extraction procedure and ICP-MS and ICP-AES for heavy metals determination. The mean fractions for all metals at all locations were: 1.5–7196 mg kg^-1 for Si, 7.79–7266 mg kg^-1 for Al, 161-639 mg kg^-1 for Cu, 19–41978 mg kg^-1 for Fe, 2.83–5864 mg kg^-1 for Zn, 1.45–13.26 mg kg^-1for Cd, 9.87–223 mg kg^-1 for Sn, 11.98-979 mg kg^-1 for Pb and 0.13–5.93 mg kg^-1 for Hg. Si, Al and Zn were mostly associated with Fe–Mn oxides, whereas Sn and Hg were mainly bound to residual and organic matter. Pb existed mainly in the residual and iron/manganese oxide phases while Cd was evenly distributed in all the five phases. The loading plots of heavy metals bound to the various chemical forms, as well as Pearson correlation coefficients, enabled the determination binding relationship. Pb, Sn and Hg exhibited similar binding behaviour which indicated an anthropogenic point source from wastes from the ship maintenance workshop, and the presence of Sn in the organic phase can be identified with the use of anti-fouling paints at the harbour, whereas Al, Fe, Si, Cu and Zn would probably be of natural origin. Lastly Cd probably came from a diffuse pollution sources in the harbour due to its unique binding characteristic. The mobility of heavy metals varied depending on location and the heavy metal type. The mobility of metals followed the order: Si > Zn > Fe > Cu> Al> Cd> Pb > Sn > Hg. The high percentage of Cd and Pb in the bioavailable forms suggested the need to keep close surveillance on these metals because of their high toxicity.     

Interaction of Lead with Calcium,Iron, and Zinc in the Biological Samples of Malnourished Children

There have been few investigations of trace elements in the urine and hair of populations exposed to high levels of arsenic (As) in drinking water. Therefore, concentrations of selected metals in urine and hair samples from a population in a study area where arsenism was endemic and a control area were determined. It was found that the median concentrations of barium (Ba), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), molybdenum (Mo), nickel (Ni), lead (Pb), zinc (Zn), and As in the urine samples from the population in the study area were 3.87, 0.47, 0.50, 61.84, 26.82, 1.33, 128.45, 7.05, 1.10, 233.75, and 339.63 μg/L, respectively. The corresponding values in the urine samples from a population in the control area were 29.08, 0.19, 0.21, 27.77, 10.32, 4.61, 14.01, 2.19, 3.90, 113.92, and 20.28 μg/L, respectively. In the study area, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, and Zn excreted in the urine were likely to be mainly derived from drinking water with high levels of arsenic. The median concentrations of Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Zn, and As in the hair samples from the study area were 4.16, 0.03, 0.09, 1.09, 6.54, 1.97, 0.06, 0.53, 1.64, 144.28, and 1.67 mg/kg, respectively. The corresponding values from the control area were 4.76, 0.03, 0.02, 1.41, 8.31, 1.34, 0.07, 0.39, 0.86, 154.58, and 0.29 mg/kg, respectively. Significant positive correlations were observed between As and Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, and Zn in the urine in the study area. However, As was not positively associated with these metals in the hair samples. Exposure to high levels of As in drinking water increased the accumulation of Ba and Mn in the hair and the excretion of Cd, Cu, and Mo in the urine in the study area. The population in the study area might experience Cu and Mo deficiencies for an increasing excretion of Cu and Mo.     

Risk Element (As,Cd, Cu,Pb, and Zn) Contamination of Soils and Edible Vegetables in the Vicinity of Guixi Smelter,South China

Risk element (As, Cd, Cu, Pb, and Zn) contamination in soils and in two edible vegetables (Solanum melongena L. and Capsicum annum L.) was investigated in the vicinity of Guixi Smelter, South China. Soil As concentrations averaged 23.9 mg/kg. Sites near the smelter tailings recorded the highest levels of As and heavy metals in soils. The concentration order of heavy metals in soils was Cd < Pb < Zn < Cu. Cu and Cd in soils were abundant in the exchangeable and bound to carbonate fraction, while Pb and Zn were in the residual fraction, limiting their potential toxicity as pollutants. The proportions of the metals in the mobile fraction followed the order Pb < Zn < Cu < Cd. In Solanum melongena L. and Capsicum annum L., Zn concentration was the highest, followed by Cu, Cd, and Pb, different from that in soils and in the mobile fraction. Concentrations of heavy metals in the labile fractions in soils and in vegetables presented significant correlation (p < 0.05). Both of the two vegetables are not the Cu and Zn accumulators. As for Cd and As, Capsicum annum L. poses a higher risk to animal and human health than Solanum melongena L., with soil-plant transfer coefficients more than three. Root-stem is the main barrier for most of the heavy metals and As in the two vegetables, resulting in higher metal concentrations in roots relative to other plant tissues. The low stem-fruit transfer coefficients for Zn in Solanum melongena L. and for Pb in Capsicum annum L. suggested that very few of them could reach the fruits.     

Reduction of bioavailability of heavy metals during vermicomposting of phumdi biomass of Loktak Lake (India) using Eisenia fetida

Abstract

Vermicomposting of phumdi biomass is a good alternative for protecting Loktak Lake and is advantageous for agriculture purposes. Research was carried out on bioavailability and leachability of nutrients (Na, K, Ca and Mg) and heavy metals (Zn, Cu, Mn, Fe, Ni, Pb, Cd and Cr) during vermicomposting of phumdi biomass for 45 days using Eisenia fetida earthworm. The bioavailability of heavy metals was determined in the form of water soluble and diethylene triamine penta-acetic acid (DTPA) extractable. The toxicity characteristic leaching procedure test was performed to determine the leachable heavy metals during the vermicomposting process. The concentration of nutrients increased during the process; whereas the concentration of water soluble, DTPA extractable and leachable heavy metals decreased significantly in all the trials. The vermicomposting of phumdi biomass by Eisenia fetida was very effective for the reduction of bioavailability and leachability of selected heavy metals. The leachability test confirmed that prepared vermicompost is not hazardous for soil, plants and human health. The possibility of using earthworms to mitigate the metal toxicity and to enhance the nutrient profile in phumdi biomass vermicompost, is advantageous in sustainable land renovation practices on a low-input basis.     

Arsenic and Heavy Metal Concentrations in Drinking Water in Pakistan and Risk Assessment: A Case Study

The present study was performed to assess drinking water quality and potential health risk in the Nowshera District, Khyber Pakhtunkhwa, Pakistan. For this purpose drinking water samples were collected from local available sources and analyzed for physico-chemical characteristics, arsenic (As) and heavy metals. Results revealed high levels of toxic heavy metals such as chromium (Cr), nickel (Ni), lead (Pb), cadmium (Cd), and As contaminations in the drinking water. Results were evaluated for chronic risk including average daily intake (ADI) and hazard quotient (HQ). Among heavy metals the HQ values were highest for Cd (5.80) and As (2.00). Therefore, populations in the study area may be at a low level of chronic toxicity and carcinogenic risk. Statistical analyses showed that contribution of different drinking water sources to the mean contaminant levels in the study area was insignificant (p =.53). Correlation analysis further revealed that anthropogenic activities were the main sources of contamination, rather than geogenic. This study strongly recommends the treatment of urban and industrial wastewater in the vicinity of the study area and provision of safe drinking water.     

Effect of carbide sludge (lime) on bioavailability and leachability of heavy metals during rotary drum composting of water hyacinth

Abstract

The bioavailability and leachability of heavy metals play a major role in the toxicity of heavy metals in the compost applied for soil conditioning. A rotary drum composter was used for the study of heavy metal bioavailability and leachability during water hyacinth composting with a mixture of cattle manure, sawdust and lime. Lime was added in 1, 2 and 3% to the mixture of water hyacinth, cattle manure and sawdust at a ratio of 6:3:1 respectively. Influences of physico-chemical parameters on heavy metal bioavailability and leachability were studied during the process. The bioavailability of heavy metals solubility and diethylene triamine penta-acetic acid extractability was examined. The toxicity characteristics leaching procedure (TCLP) test was performed for assessing the hazardous properties of compost. The nutrients and the total concentration of heavy metals were increased during the composting process. The lime was very effective in reducing water solubility, plant availability and leachability of the selected heavy metals (Zn, Cu, Mn, Fe, Ni, Pb, Cd and Cr) during the process. The addition of lime provided a buffer against the decrease in pH and a sufficient amount of Ca that would improve the metabolic activity during composting. The addition of an excess amount of lime slowed the metabolic activity of the microbes due to its high alkalinity. The TCLP test confirms that the heavy metals concentrations in the control and in the lime-amended compost were below the threshold limits.     

Assessment of Heavy Metals and Metalloids in Solanum tuberosum and Pisum sativum Irrigated with Urban Wastewater in the Suburbs of Sargodha City,Pakistan

Dietary exposure to heavy metals (viz., Ni, As, Fe, Cr, Mn, Co, Mo, Cu, Zn, Se, Cd, and Pb) has been recognized as a potential hazard to human health. This study investigates the level of contamination at two different sites in Pakistan, one irrigated with canal water (Site-I) and the other with urban wastewater (Site-II). At Site-II, irrigation with wastewater resulted in a significant increase in heavy metals and metalloids in soil and a subsequent build-up in two vegetables selected for study (Solanum tuberosum [potato] and Pisum sativum [pea]). Results showed that mean concentrations of heavy metals and metalloids in soil at Site-I were lower than those of Site-II. Mean concentrations of As and Cd in soil at both sites and for both vegetables were found above maximum permissible levels, while for both vegetables As at both sites and Cd, Mo, and Pb exceeded the suggested maximum levels for vegetables. High levels of some metals in the soils and vegetables could be due to unnecessary use of fertilizers and disposable water for irrigating the soils and the environmental cues prevalent in the areas, such as presence of ions that may bind the metals, often play an important role in uptake.     

微生物驱动硝酸盐还原耦合亚铁氧化成矿过程的锌胁迫

【目的】探究中性厌氧条件下,金属锌影响下硝酸盐依赖型铁氧化菌Pseudomonas stutzeri LS-2驱动的硝酸盐还原耦合亚铁氧化成矿过程机制,对深入理解中性厌氧环境中微生物亚铁氧化驱动的反硝化作用及重金属固定机制具有重要意义。【方法】以不同Zn(Ⅱ)浓度构建LS-2驱动的亚铁氧化成矿体系,分析不同体系中亚铁氧化速率、硝酸盐还原速率以及形成矿物的结构变化规律。【结果】LS-2驱动的硝酸盐还原耦合亚铁氧化成矿过程中,共存Zn(Ⅱ)降低该过程中硝酸盐的还原速率和亚铁氧化速率。同时,随着Zn(Ⅱ)浓度提高,抑制作用增强。微生物亚铁氧化形成的矿物通过吸附、共沉淀和离子置换等过程固定Zn(Ⅱ),降低Zn(Ⅱ)活性。Zn(Ⅱ)浓度对形成的矿物结构有较大的影响:低浓度Zn(Ⅱ)体系中,形成的矿物为纤铁矿;随着Zn(Ⅱ)浓度的提高,矿物结构与结晶度都有一定程度的变化,当Zn(Ⅱ)达到4 mmol/L时,形成的矿物主要为铁锌尖晶石。【结论】明确了重金属锌对LS-2菌株反硝化及亚铁氧化过程的抑制规律,同时阐明了Zn(Ⅱ)浓度对形成矿物结构的影响。研究结果有助于深入认识中性厌氧环境中重金属与微生物驱动的铁循环和反硝化过程的耦合作用,为土壤重金属污染防治提供理论支撑。     

Use of granules and free salts for Fe and Zn fortification of leafy vegetables: Improvements in trace element bioaccessibility and fulfillment of Dietary Reference Intakes

BackgroundLeafy vegetables represent an excellent dietary source of trace elements such as Fe and Zn. Nevertheless, Fe and Zn bioaccessibility can lessen due to a high concentration of anti-nutritional compounds. The encapsulation of Fe and Zn salts as granules could be used to fortify these leafy vegetables.MethodThree leafy vegetables, spinach, Swiss chard and Ethiopian mustard were fortified with iron sulfate and zinc sulfate as granules and free salts in order to test the improvements in the bioaccessibility and fulfillments of DRIs. Fe and Zn granules were prepared in a fluidized bed granulator. A probabilistic analysis was performed, using experimental data, to assess bioaccessible intake and fulfillments of DRIs in European populations.ResultsFe contents ranged between 4.8 mg/100 g of Ethiopian mustard to 157.4 mg/100 g of spinach. Fe and Zn bioaccessibility percentages were low for Swiss chard and spinach without fortification. Fortification with granules improved Fe bioaccessibility of these latter vegetables (196 and 223 mg/100 g). Zn contents in samples without fortification ranged between 2.3 mg/100 g for Ethiopian mustard and 7.4 mg/100 g for spinach. Zn fortification as granules improved Zn bioaccessibility for the three vegetables studied. Thus, Zn bioccessible concentrations ranged between 17.4 and 108 mg/100 g for the solubility assay and between 5.9 and 31.1 mg/100 g for the dialyzability assay. Besides, the probability analysis showed that fortification had a better performance in meeting DRIs for those populations with higher consumption levels of leafy vegetables.ConclusionsThe probability analysis demonstrated that fortification can be a suitable strategy to meet DRIs for both trace elements, which was especially remarkable for Fe. Fortification with granule was more effective in most the cases, although for Ethiopian mustard, free salt of Fe showed a better performance.     

碳酸钙对水稻吸收重金属(Pb、Cd、Zn)和As的影响

选用重金属(Pb、Cd、Zn)和As复合污染土壤进行水稻盆栽试验,结果表明,碳酸钙的添加显著提高了土壤pH值,显著降低了土壤中交换态Pb、Cd、Zn和As的含量,与对照相比,交换态Pb、Cd、Zn和As含量分别最多降低了98.35%,93.72%,98.52%和69.48%。碳酸钙对水稻根、稻谷干重和总生物量没有显著影响,添加量过高时显著降低了水稻分蘖数和茎叶干重,说明过量施用碳酸钙对水稻生长会产生负面作用。因为碳酸钙的添加,水稻植株各部位重金属Zn含量显著降低,糙米中Zn含量最多减少了34.95%;根、谷壳中Pb、Cd含量显著降低,但糙米中含量却未显著降低;水稻各部位As含量均没有显著降低。参照《食品中污染物限量》(GB2762—2012),试验糙米中Pb、Cd、无机As含量均未达到限量标准。显然,碳酸钙的添加降低了Pb、Cd、Zn的生物有效性(水稻根系对Pb、Cd、Zn的吸收累积减少),但并未有效地抑制Pb、Cd向糙米转运;碳酸钙显著降低了土壤的交换态As含量,但并未使土壤中As的生物有效性明显降低(水稻植株各部位的As含量并未显著减少)。     

Geochemical distribution and fractionation of heavy metals in sediments of a freshwater reservoir of India

Abstract

Sediments of a polluted reservoir were evaluated for total contents of Cd, Cr, Cu, Ni, Pb and Zn along with their different geochemical forms (exchangeable, carbonate, Fe–Mn, organic matter and residual). Mineralogy of the sediments and physico-chemical parameters i.e. pH, OC and percentage of sand, silt and clay were also evaluated to see the dependency of heavy metals concentration on these parameters. The total concentration of heavy metals in the sediments varied according to sites and seasons. Except for station H1 which had moderately higher concentration of Cu (45.5 mg kg^-1), concentrations of all other metals at all the sites under study were below the standard shale value. Maximum proportions of all metals were associated with the carbonate and residual fractions. The Risk Assessment Code showed a low risk for Cr, Ni and Zn, and a medium risk for Cu at station H3 and H4. On the basis of freshwater sediment quality guidelines, there is a strong possibility of Cr and Cu toxicity for aquatic biota of the reservoir. The data were further processed using Pearson’s correlation and factor analysis to obtain more accurate information about the behaviour of these metals. A positive relationship among the metals confirmed the anthropogenic sources of pollution in the reservoir. Significant positive relationships of heavy metals with the texture of the sediment were also obtained.     

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.