Effect of the behavior and availability of heavy metals on the characteristics of the coastal soils developed from alluvial deposits

An investigation of the behavior and availability of heavy metals (HMs), i.e., Cu, Zn, Ni, Pb, Cr, and Cd, based on the analysis of correlation between HMs and physical and chemical properties of coastal soils developed from alluvial deposits in Shanghai, China, has been conducted, in order to reveal the effect of the soil formation and development and the unsuited human activities on the activities and mobility of HMs in agricultural soils. The results showed that (1) the soils still meet the needs of plant growth due to the moderate fertility with a soil texture of silty loam although the content of organic matters is lower, (2) total heavy metal content had a increase trend from the inland area to the coastal area, indicating the impact of alluvial deposits related to the soil formation on the distribution of HMs; (3) a significant positive correlation was found between HMs and some soil properties (i.e., clay content, cation exchange capacity, organic matters, total Phosphorous content, etc.), indicating that the regulation of these properties could give some great effect on the behavior and availability of HMs; (4) the positive correlation among Cu, Zn, Ni, and Cd, and between Pb and Cr is very significant, suggesting the most similar, if not the same, origins of HMs; These findings are helpful to the soil remediation, fertility adjustment, and plant cultivation.     

The function of constructed wetland in reducing the risk of heavy metals on human health

Irrigation with polluted water from the upper Yellow River (YR) channel of Northwest China has resulted in agricultural soil being contaminated by heavy metals (HMs). This causes major concerns due to the potential health risk to the residents in this area. The present study aims to assess the efficiency of constructed wetland (CW) in reducing the heavy metal contamination in irrigation water and food crops, thus in reduction of potential health risk to the residents. The associated risk was assessed using hazard quotient (HQ) and hazard index (HI). The results showed a potential health risk to inhabitants via consumption of wheat grain irrigated with untreated water from YR. However CW could greatly reduce the human health risk of HMs contamination to local residents through significantly decreasing the concentrations of HMs in wheat grain. In theory, the reduction rate of this risk reached 35.19% for different exposure populations. Therefore, CW can be used as a system to pre-treat irrigation water and protect the residents from the potential HMs toxicity.     

Availability and mobility of heavy metal fractions related to the characteristics of the coastal soils developed from alluvial deposits

The availability of the five chemical fractions, i.e., exchangeable (F1), carbonate-bound (F2), Fe/Mn oxide-combined (F3), organic matter-complexed (F4), residual (F5), of three heavy metals (Cu, Zn, and Cd), has been investigated by way of a sequential extraction technique based on the characteristics of the coastal soils developed from alluvial deposits, in order to analyze the relationship of the formation and development of coastal soils. The results showed that F1 and F5 of Cu, Zn, and Cd accounted dominantly for 9.11%, 2.74%, and 20.37%, and for 39.49%, 45.18%, and 32.43% of total heavy metal contents, respectively, indicating the order of availability and mobility: Cd > Cu > Zn. F2, F3, and F4 of HMs also featured prominently in the behaviors of heavy metals. Random measurement errors from both sampling and analysis were demonstrated by SAX to be well within the control target of 20% and, therefore, of no impediment to the geochemical interpretation of the data. Significant positive correlation was found between certain fractions of heavy metals and some soil properties. Some negative correlation was also found. The findings were helpful to the soil remediation, fertility adjustment, and plant cultivation.     

Heavy metals in jujubes and their potential health risks to the adult consumers in Xinjiang province,China

The concentrations of seven heavy metals (HMs) in jujube samples collected from Hetian region (HTR), Hami region (HMR), Erkesu region (ESR), Bayikuleng region (BLR), and Turpan region (TUR) were determined by inductively coupled mass spectrometry (ICP-MS). The accuracy and precision of the analytical method were confirmed by the certified reference material (GBW 07605). In general, the concentration of iron was higher than those of the other six metals in the investigated jujube samples. The Hazard Quotient (HQ) and Hazard Index (HI) were calculated to evaluate the noncarcinogenic health risk from individual metal and combined metals due to the dietary intakes via consumption of jujube. Both HQ and HI levels were far below 1, suggesting no noncarcinogenic risks for Xinjiang adults under the current consumption rates of the jujubes. Among the jujubes from five different regions, BLR jujube had the highest HQ and HI. Fe and As were the most concerning HMs in the investigated jujube samples due to their higher relative contributions to HIs.     

Genotoxicity of the sediments collected from Pearl River in China and their polycyclic aromatic hydrocarbons (PAHs) and heavy metals

The accelerated industrialization and urbanization in the last three decades around the Pearl River Delta within Guangdong Province in China have led to serious concerns about the impacts on the aquatic environment. In the present study, the genotoxicity of the sediments collected from the Pearl River was evaluated by micronucleus (MN) assay with Vicia faba root tip cells, and the 16 EPA priority polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs, including Cr, Cu, As, Se, Cd, Hg, and Pb) in the sediments were determined respectively by GC-MS, inductively coupled plasma mass spectrometry, and inductively coupled plasma atomic emission spectrometry. The results showed that there were significant increases of MN frequencies observed in the sediment-exposed groups, compared with the negative group (P?相似文献   

The characteristics of size distribution of suspended particulates in the air for sulphates and selected metals in different areas and seasons

The characteristics of the distribution of particles by size were investigated for sulphates and selected metals (Pb, Fe, Mn, and Cu) in the air in two urban and an industrial area during the winter and summer periods using an Andersen cascade impactor.In the case of metals, but not sulphates, the character of the area affected the value of mass median diameter. Lowest values were obtained in a sparsely populated urban area, whereas in a densely populated urban area and in the industrial area the values were higher.In the industrial area a high correlation coefficient was found between sulphate and manganese, and between sulphate and lead, as well as a high value of the equivalent Mn²⁺/SO _inf4 ^sup2- ratio for the total sample. It may therefore be assumed that in the industrial area manganese produces a catalytic effect on SO₂ conversion to sulphate. Among the investigated metals lead stands out as a dominant cation which binds to the sulphate ion in the industrial and densely populated areas.     

Effects of selected soil properties on phytoremediation applicability for heavy-metal-contaminated soils in the Apulia region, Southern Italy

Phytoremediation is a well-known promising alternative to conventional approaches used for the remediation of diffused and moderated contaminated soils. The evaluation of the accumulation, availability, and interactions of heavy metals in soil is a priority objective for the possible use of phytoremediation techniques such as phytoextraction and phytostabilization. The soils used in this work were collected from a number of sites inside a protected area in the Apulia region (Southern Italy), which were contaminated by various heavy metals originated from the disposal of wastes of different sources of origin. Soils examined contained Cd, Cr, Cu, Ni, Pb, and Zn in amounts exceeding the critical limits imposed by EU and Italian laws. However, the alkaline conditions, high organic matter content, and silty to silty loamy texture of soils examined would suggest a reduced availability of heavy metals to plants. Due to the high total content but the low available fraction of heavy metals analyzed, especially Cr, phytoextraction appears not to be a promising remediation approach in the sites examined, whereas phytostabilization appears to be the best technique for metal decontamination in the studied areas.     

典型铝塑厂周边土壤重金属分布特征与健康风险评价

为探究铝塑园区周边土壤重金属污染情况,选取山东省某城市塑料开发区为研究区,按照分层采样方式获取到80个土壤样品,分别测定土壤中As、Cd、Hg、Cr、Cu、Ni、Pb、Zn含量,运用统计分析法探讨土壤重金属等的分布特征和来源,并利用健康风险评价模型确定了土壤重金属对周边居民的健康风险。结果表明:As、Cd、Hg、Cr、Cu、Ni、Pb和Zn均超出山东省土壤背景值,其中Cd、Hg、Cu和Pb分别超出背景值48. 15%、106. 90%、62. 04%和39. 96%,表明土壤中存在一定程度的重金属积累,在周边140～210 m处最为严重,且受人类活动影响强烈,与风向关系不大;土壤重金属垂直分布特征大致呈现随着深度的增加不断增加,在20 cm深度附近达到最高值,其后不断降低并趋于平稳,Cd、Hg、Cu、Pb和Zn变异幅度大,受到人为干扰较大,As、Cr和Ni主要受成土母质控制,属于自然来源,变动幅度较小;研究区内8种元素不存在非致癌风险,Cr、As、Ni和Cd产生的致癌风险处在可接受范围内,但存在的潜在致癌风险应引起足够的重视。     

Macroalgae and DGT as indicators of available trace metals in marine coastal waters near a lead–zinc smelter

The levels of Cd, Cu, Pb, and Zn were determined in the commonest species of green, red, and brown algae collected from five coastal sites in south-western Sardinia (Italy), an area with a long history of mining and smelting. The usefulness of employing Enteromorpha sp. and Padina pavonica (L.) Thivy to monitor metal pollution was evaluated, while diffusive gradients in thin films (DGT) devices were used to measure dissolved metals in seawater. Levels of Cd and Pb were high enough to be of environmental concern in the whole study area. A significant relationship was found between the content of Pb in P. pavonica and DGT-labile Pb in seawater, suggesting that gross elemental concentrations of nonessential metals such as Pb in algal tissues are apparently controlled by the abundance of dissolved metal species in the ambient seawater. The results pointed out the usefulness of using both DGT and algal methods for a better understanding of trace metal availability in coastal waters.     

燃煤电厂周边大气重金属污染特征及来源解析

为探究燃煤电厂周边大气环境中重金属的污染特征与来源,对广东某山区燃煤电厂周边地区环境和污染源的重金属进行测定,分析其污染特征,采用因子分析法和Pb同位素示踪法对环境中的重金属进行来源解析。结果表明,研究区域室内积尘中重金属浓度水平明显高于土壤重金属,污染空间分布与当地气象条件相关。环境空气TSP中重金属主要来自2个污染源,Cd、Pb、As主要来自电厂燃煤,Ca、Mn、Al、Mg主要来自土壤扬尘。TSP、降尘、积尘样品所含的Pb均与电厂采集的煤、炉渣、粉煤灰样品所含的Pb具有同源性,与其他污染源同源性不明显,说明研究区域大气中Pb污染主要来自电厂燃烧所排放的烟尘,其他污染源影响不大。     

Toxic metals status in kidneys and gallstones of workers in a steel plant environment

Samples of kidney stones and gallstones obtained from patients who were workers at a steel plant, or residents of the steel plant township area and those unrelated to the steel plant and steel plant township area were analysed for the presence of toxic metals (Zn, Cr, Ni, Co, Cu, Pb, Hg, Cd and Mn) by atomic absorption spectrophotometry. Other constituents (moisture, organic matter, oxalate, phosphate, fluoride and calcium) were also determined in each sample. In most of the samples the highest occurrence of toxic metals was found in the samples obtained from workers of the steel plant who were also residents of the steel plant township area. In samples obtained from patients who were non-workers of the plant but residents of the steel plant township area, the concentrations of the toxic metals were smaller, but higher than in those cases who were unrelated to the steel plant environment.     

薄膜扩散梯度技术在重金属生物有效态监测中的应用

重金属生物有效性是评估重金属元素迁移性、生物可利用性和生态影响的关键参数。薄膜扩散梯度技术(DGT)是一种原位被动采样技术,因其具有原位富集性、形态选择性,可提供被监测物质在监测时间段内的平均浓度等优点,可作为生物对重金属摄取的模拟替代物对环境介质中重金属的生物可利用度进行预测,已被广泛应用于环境介质中重金属生物有效性的测定。研究主要介绍了DGT技术的原理、组成和特点,评述了其近年来在水体、土壤、沉积物中重金属生物有效态应用方面的新进展,提出了DGT技术未来要提高抗生物污染能力及寻找可与DGT技术联用的相关技术的观点。     

Spatial variation of acid-volatile sulfide and simultaneously extracted metals in Egyptian Mediterranean Sea lagoon sediments

In risk assessment of aquatic sediments, the immobilizing effect of acid-volatile sulfide (AVS) on trace metals is a principal control on availability and associated toxicity of metals to aquatic biota, which reduces metal bioavailability and toxicity by binding and immobilizing metals as insoluble sulfides. Spatial variation pattern of AVS, simultaneously extracted metals (SEM), and sediment characteristics were studied for the first time in surface sediment samples (0–20 cm) from 43 locations in Egyptian northern delta lagoons (Manzalah, Burullus, and Maryut) as predictors of the bioavailability of some divalent metals (Cu, Zn, Cd, Pb, and Ni) in sediments as well as indicators of metal toxicity in anaerobic sediments. The results indicated that the ∑SEM (Cu?+?Zn?+?Cd?+?Pb?+?Ni) values in sediments of lagoon Burullus had higher concentrations than those of Maryut and Manzalah. In contrast, AVS concentrations were considerably higher in lagoons Manzalah and Maryut and seemed to be consistent with the increase in organic matter than lagoon Burullus. Generally, the average concentrations of the SEM in all lagoons were in the order of Zn?>?Cu?>?Ni?>?Pb?>?Cd. The ratios of ∑SEM/AVS were less than 1 at all the sampling stations except at one station in lagoon Maryut as well as four stations located in lagoon Burullus (∑SEM/AVS?>?1), which suggests that the metals have toxicity potential in these sediments. Therefore, SEM concentrations probably are better indicators of the metal bioavailability in sediments than the conventional total metal concentrations.     

Assessment of the effects of Cr, Cu, Ni and Pb soil contamination by ecotoxicological tests

This study aimed to assess soil quality by chemical and ecotoxicological investigations and to check the correspondence between soil metal concentrations and ecotoxicity. For these purposes, surface soils collected at four adjacent roadside urban parks and at a former industrial area were characterized for C/N, organic matter content, texture, and pH. Cr, Cu, Ni and Pb, chosen among the most representative soil metal contaminants, were measured as total content and as available and water soluble fractions. In addition, the total concentrations of the investigated metals were used to calculate two chemical indices: the contamination and the potential ecological risk factors. The toxicity of the investigated soils was evaluated by an ecotoxicity test battery carried out on both soil samples (Vibrio fischeri, Heterocypris incongruens and Sinapis alba) and elutriates (Vibrio fischeri, Daphnia magna and Selenastrum capricornutum). The findings, both by the chemical and ecotoxicological approaches, would suggest that the soils with high metal contamination pose ecological risks. On the other hand, moderately metal contaminated soils did not exclude soil ecotoxicity. In fact, toxic effects were also highlighted in soils with low metal content, toxicity being affected by metal availability and soil characteristics. Moreover, the results suggest the importance of using a battery of tests to assess soil ecotoxicity.     

Distribution and speciation of selected metals in surface sediments, from the tropical Zuari estuary, central west coast of India

Estuarine sediments are major reservoirs for the metals. Distribution and mobility of metals within estuaries depends strongly on their specific chemical form. In the present study, surface sediments from Zuari estuary, Goa were analysed by a sequential procedure for Fe, Mn, Cu, Zn, Cr and Co to determine their distribution in five geochemical phases (Exchangeable, carbonate, Fe-Mn oxide (reducible) organic bound (oxidisable) and residual). The total metal content, sand, silt, clay and organic carbon were also determined of the surface sediments. The total metal contents were found to be greater than the background concentrations of average shale values as well as to that of earlier studies indicating enrichment probably due to the anthropogenic origin of metals. The results obtained from sequential procedure showed that among the studied elements, Mn and Co are potentially available in the bioavailable fractions (exchangeable, carbonate and Fe-Mn oxide bound fractions) indicating their importance in toxicity whereas rest of the metals viz. Fe, Cu, Zn and to some extent Cr are largely available in residual phase although they are available in other fractions. The main source of metals to the estuary is mining and its associated activities in the study area. Chemical speciation by sequential extraction procedure has helped in assessing the mobility, bioavailability, diagenesis and toxicity of metals and hence giving a better insight into the ultimate fate of pollutants, which are introduced into the estuarine environment. To understand the risk of the metals to the sediment dwelling organisms the data were compared with the Sediment Quality Values (SQV) using SQUIRT. Also, correlation and Factor analysis were carried out to understand the associations of metals in the different fractions with sand, silt, clay, organic carbon and with other metals.     

Determination of total and EDTA extractable metal distributions in the colloidal fraction of contaminated soils using SdFFF-ICP-HRMS

Newly developed methods involving an on-line combination of sedimentation field-flow fractionation-inductively coupled plasma-high resolution mass spectrometry (SdFFF-ICP-HRMS) have been used to study the distributions of extractable heavy metals in a soil which had been treated with sewage sludge contaminated with Cu or Pb. The relationship of these metals with other elements in the colloidal fraction was also investigated. The colloidal fraction from the soil was obtained by repeated gravitational sedimentation and extracted with 0.11 M acetic acid, 0.1 M hydroxylamine hydrochloride, 0.05 M ethylenediaminetetraacetic acid disodium salt (EDTA) or aqua regia to assess the potential availability of the metals Cu and Pb. Large proportions of the Cu and Pb were extracted by EDTA, approaching that removed by aqua regia, whereas < 10% of the aqua regia extractable metals were removed by acetic acid and hydroxylamine chloride. The distributions of the heavy metals, the major mineral forming element (Al) and the elements forming sesquioxides (Fe and Mn) within different size classes (0.05-1 microm) of the colloidal fraction were measured using SdFFF-ICP-HRMS before and after extraction with EDTA. This information provides an insight into the composition of the colloids and the distributions of metal contaminants. In the contaminated soil colloids, the concentration of Fe, Mn and Pb is greatest in the smaller particles (<0.2 microm). In contrast, the Cu concentration is constant over the size range studied. Iron oxide surface coatings probably play a significant role in Pb adsorption on soil particles, but may be less important for Cu. The combination of selective chemical extraction, SdFFF and ICP-HRMS provides a means of determining the distribution of potentially available heavy metals within the colloidal fraction of contaminated soils.     

Influence of a collapsed coastal landfill on metal levels in sediments and biota--a portent for the future?

In May 2008 a coastal landslide deposited landfill debris onto the shore near Lyme Regis, UK. Six months later, intertidal sediments and biota from the area were sampled to determine whether the landslip had affected distribution and bioavailability of metals in the area and if there were any biological effects. Highest sediment concentrations for the majority of metals occurred near the landslip zone and in several cases exceeded Threshold Effects or Probable Effects Levels (As, Cu, Hg, Ni, Pb, Zn). The 1 M HCl-extractable fraction of Cd, Pb and Zn in sediments also increased near the landslip. Metal bioaccumulation by intertidal biota showed variability between different species and metals, but there were several instances of increased accumulation near the landslip through increased availability from seawater, sediment and dietary sources. In most cases, metal concentrations in molluscs exceeded Oslo and Paris Commission (OSPAR) background concentrations (BCs) together with background assessment concentrations (BACs) at some sites. Kidney tissues in winkles (Littorina littorea) were measured for evidence of oxidative stress using the Total Oxyradical Scavenging Capacity (TOSC) assay. Responses to peroxynitrite, peroxyl and hydroxyl radicals suggested raised levels of TOSC in animals from the sites close to or east of the landfill waste. There have been very few studies of direct impact of landfills on the marine environment and this study could serve as a practical model for similar events driven by sea level rise.     

A field screening test for the assessment of concentrations and mobility of potentially toxic elements in soils: a case study on urban soils from Rome and Novi Sad

The increasing demand for environmental pollution control results in the development and use of new procedures for the determination of dangerous chemicals. Simple screening methods, which can be used directly in the field for a preliminary assessment of soil contamination, seem to be extremely advantageous. In our laboratory, we developed and optimized a rapid test for a preliminary evaluation of both the concentration and the mobility of some potentially toxic metals in soils. This screening test consists of a single extraction of the soil sample with a buffer solution, followed by the titration of the extracted solution with dithizone to determine the contents of bi-valent heavy metals (such as Pb, Cu, Zn, and Cd). This screening method was then directly applied in the field during the sampling campaign in the framework of an Italian–Serbian collaborative project, finalized in the study of metal availability in soils. The results obtained in the field with the rapid test were compared with those obtained in the laboratory following the conventional procedure commonly used to evaluate metal bioavailability (diethylenetriaminepentaacetic extraction). Moreover, selected samples were analyzed sequentially in the laboratory using the standardized BCR three-step sequential extraction procedure. The screening test gave results conceptually in good agreement with those obtained via the BCR procedure. These preliminary data show that the proposed screening test is a reliable method for the preliminary rapid evaluation of metal total concentrations and of potential metal mobility in soils, supporting sampling activities directly in the field.     

Source identification study of heavy metal contamination in the industrial hub of Unnao,India

India's Unnao region is home to many leather-treatment facilities and related industries. Industrial and agricultural waste leads to heavy metal contamination that infiltrates groundwater and leads to human health hazards. This work measured the amount of heavy metal in groundwater at specific sites near the industrial facilities in Unnao and identified potential sources of contamination as anthropogenic or lithogenic. Groundwater samples were taken from 10 bore well sites chosen for depth and proximity to industry. Data obtained from sample sites was interpreted using a multivariate statistical analytical approach, i.e., principal component analysis, clustering analysis, and correlation analysis. The results of the multivariate analysis showed that cadmium, copper, manganese, nickel, lead, and zinc were correlated with anthropogenic sources, while iron and chromium were associated with lithogenic sources. These findings provide information on the possible sources of heavy metal contamination and could be a model for assessing and monitoring heavy metal pollution in groundwater in other locales. This study analyzed a selection of heavy metals chosen on the basis of industries located in the study area, which might not provide a complete range of information about the sources and availability of all heavy metals. Therefore, an extended investigation on heavy metal fractions will be developed in further studies.     

Ecological interpretation of metal contents and contaminant source characterisation of sediments from a megatidal estuary

Sediments and the associated biota constitute an important compartment in the biogeochemical cycle of trace metals in soft substrate megatidal estuaries. The relationship between physicochemical, ecological properties, metal concentrations determined in megatidal estuary sediments from the French coast of the English Channel, the Baie des Veys and the macrobenthic organisms, are analysed, interpreted and reported. Total concentrations of zinc, cadmium, lead and copper were measured in mudflats and saltmarsh sediments using Differential Pulse Voltammetry. Sediment characteristics were obtained by measurement of particle size, water content, total organic carbon and carbonate content, using AFNOR standards. A semi-quantitative scale was used for assessing the density of the macrobenthic flora and fauna at each sampling site. Analysis of data obtained from this study showed a correlation between the concentrations of monitored trace metals and species of the macrobenthic fauna. The results of this study show that the physico-chemical characteristics of the sediments affect the retention of metals in the sediment and this in turn affects the biota.