重庆市居民头发重金属富集特征及相关性分析

本研究利用火焰原子吸收法测定了重庆主城与郊区居民头发中镉、铜、镍、铅和锌等5种重金属的浓度水平,比较分析了人发中5种重金属含量水平及与年龄、性别和吸烟与否的关系,最后通过相关性分析和主成分分析初步了解重庆居民人发中重金属可能的来源.结果表明,重庆主城人发中Cd、Cu、Ni、Pb和Zn的平均含量分别为3.1、24.3、9.7、42.8和209.6 μg·g^-1,郊区居民人发的平均含量分别为0.9、15.8、5.6、15.2和173.4 μg·g^-1;5种重金属在主城居民头发中的含量均显著高于郊区居民头发中含量（t-检验,P<0.01）,并且其组成与居民附近土壤样品的组成基本一致;5种重金属的含量在不同年龄段人群中的分布没有明显趋势,只是在郊区居民头发中的Cu和Zn含量随着年龄增长而减少;主城和郊区男性头发中Cd和Pb含量均显著高于女性（P<0.01）,并且在主城和郊区吸烟者头发中的Cd和Pb显著高于非吸烟者（P<0.01）;通过相关性分析发现主城和郊区中Cd、Cu、Ni和Pb之间具有相似的相关性模式,并且主成分分析结果显示,在主城中,人发Cu、Ni和Pb具有相似的来源,而在郊区中,人发Cd、Ni和Pb具有相似的来源.     

高架道路周边建筑物灰尘重金属污染风险:以常州市为例

在常州环城高架道路两侧6个住宅小区不同楼层采集126个灰尘样品,测定Cu、Zn、Pb、Cd、Ni和Cr含量,分析其化学形态和垂直分布特征,采用富集系数和风险评价指数评价其污染程度和生物有效性,并进行潜在生态风险评价和健康风险评价.结果表明,灰尘中Cu、Zn、Pb、Cd、Ni和Cr含量均值分别为181.95、709.99、211.24、2.76、101.59和257.55mg·kg-1,均远大于背景值.灰尘中Cd的富集系数为33.05,富集程度为强烈,Cu、Pb和Zn的富集程度为显著富集,它们可能受到自然源、交通源和区域废气传输的综合影响,Ni和Cr富集系数较低,可能主要受自然源影响.随楼层高度的上升,Cd含量呈增加趋势,Pb和Zn含量呈先增加后降低趋势,Cu含量无显著变化.Zn、Cd、Cu和Pb主要以活性态存在,生物有效性较高,Ni和Cr以残渣态为主,生物有效性较低.改进的潜在生态风险评价结果表明,Cd的潜在生态风险极高,对多元素的潜在生态风险起主导作用,且对高层楼的潜在生态风险较大,其它重金属潜在生态风险为中低级.健康风险评价结果表明,Cr对儿童的致癌风险超过安全阈值,其它重金属对成人与儿童致癌风险及非致癌风险均在安全域之内.     

紫色水稻土颗粒有机质对重金属的富集特征

在重庆合川区和铜梁区随机采集了20个紫色水稻土,将其分成颗粒有机质(0.053~2 mm,POM)、砂粒(0.053~2mm)和细土(0.053 mm)这3个组分,通过比较不同组分的有机碳及重金属(Cu、Zn、Pb、Cd)含量和分布状况,研究了紫色水稻土中POM对重金属的富集特征及其与土壤理化性质如pH、CEC、黏粒和土壤有机碳(SOC)等的关系.结果表明,采样区紫色水稻土的POM含量范围为7.31~44.76 g·kg~(-1),平均值为19.20 g·kg~(-1),有机碳含量为96.61~263.17 g·kg~(-1),平均值为151.34 g·kg~(-1),显著高于原土及其他组分,对土壤有机碳的贡献率为8.63%~48.62%,代表了一大部分土壤有机碳库.POM中的Cu、Zn、Pb和Cd平均富集系数分别为3.35、1.14、2.88和2.14,显著高于其他组分,表现出一定的富集作用,对上述重金属的贡献率分别为6.02%、2.22%、5.24%和3.21%,POM对Cu、Pb的富集能力和贡献率均显著大于Zn和Cd.相关分析结果表明,POM含量与SOC、pH、CEC、黏粒(0.002 mm)呈显著或极显著正相关,SOC是主要因素.POM-C含量与总量分别与黏粒含量、SOC呈显著相关.POM中重金属总量与SOC、pH、POM-C总量呈显著或极显著正相关,SOC是最关键因子;与其他重金属相比,Zn在POM中的总量与土壤性质的回归系数最高,关系最为密切.     

基于地理探测器的土壤重金属影响因子分析及其污染风险评价

地理探测器能快速定量化揭示驱动重金属含量影响因素的强度,这对于重金属空间预测模型构建变量的确定和土壤污染修复措施的精准实施具有重要意义.利用地理探测器模型,对5种土壤重金属元素Cu、Zn、Pb、Cr、Ni的空间分布和11种环境因子的交互作用进行定量评估,通过单因子指数法进行重庆市土壤重金属污染风险评价.结果表明:研究区...     

澳门特别行政区土壤自然消减能力与污染背景

澳门是我国人口密度最大的城市.选择澳门特别行政区不同功能区绿地土壤为研究对象,首先,通过野外布点采样,调查分析了表层土壤中9种重金属元素(Cr、Ni、Cu、Cd、Pb、Cr、Zn、As、Hg)和16种优先控制多环芳烃(PAHs)的分布特征;其次,利用累积频率分布曲线法估算了土壤重金属和PAHs的土壤污染背景;最后,基于...     

Influence of tidal regime on the distribution of trace metals in a contaminated tidal freshwater marsh soil colonized with common reed (Phragmites australis)

A historical input of trace metals into tidal marshes fringing the river Scheldt may be a cause for concern. Nevertheless, the specific physicochemical form, rather than the total concentration, determines the ecotoxicological risk of metals in the soil. In this study the effect of tidal regime on the distribution of trace metals in different compartments of the soil was investigated. As, Cd, Cu and Zn concentrations in sediment, pore water and in roots were determined along a depth profile. Total sediment metal concentrations were similar at different sites, reflecting pollution history. Pore water metal concentrations were generally higher under less flooded conditions (mean is (2.32 ± 0.08) × 10⁻³ mg Cd L⁻¹ and (1.53 ± 0.03) × 10⁻³ mg Cd L⁻¹). Metal concentrations associated with roots (mean is 202.47 ± 2.83 mg Cd kg⁻¹ and 69.39 ± 0.99 mg Cd kg⁻¹) were up to 10 times higher than sediment (mean is 20.48 ± 0.19 mg Cd kg⁻¹ and 20.42 ± 0.21 mg Cd kg⁻¹) metal concentrations and higher under dryer conditions. Despite high metal concentrations associated with roots, the major part of the metals in the marsh soil is still associated with the sediment as the overall biomass of roots is small compared to the sediment.     

Kinetic extractions to assess mobilization of Zn, Pb, Cu, and Cd in a metal-contaminated soil: EDTA vs. citrate

Kinetic EDTA and citrate extractions were used to mimic metal mobilization in a soil contaminated by metallurgical fallout. Modeling of metal removal rates vs. time distinguished two metal pools: readily labile (QM1) and less labile (QM2). In citrate extractions, total extractability (QM1+QM2) of Zn and Cd was proportionally higher than for Pb and Cu. Proportions of Pb and Cu extracted with EDTA were three times higher than when using citrate. We observed similar QM1/QM2 ratios for Zn and Cu regardless of the extractant, suggesting comparable binding energies to soil constituents. However, for Pb and Cd, more heterogeneous binding energies were hypothesized to explain different kinetic extraction behaviors. Proportions of citrate-labile metals were found consistent with their short-term, in-situ mobility assessed in the studied soil, i.e., metal amount released in the soil solution or extracted by cultivated plants. Kinetic EDTA extractions were hypothesized to be more predictive for long-term metal migration with depth.     

Heavy metal accumulation in Littoraria scabra along polluted and pristine mangrove areas of Tanzania

The periwinkle Littoraria scabra was collected at polluted and pristine mangrove sites along the Tanzanian coastline, including Msimbazi, Mbweni (i.e. Dar es Salaam) and Kisakasaka, Nyamanzi and Maruhubi (i.e. Zanzibar). Periwinkles were morphologically characterized, sexed and their heavy metal content was determined using ICP-MS. Analysis revealed that L. scabra from polluted areas contained higher soft tissue heavy metal levels, were significantly smaller and weighed less compared to their conspecifics from the unpolluted mangroves. The current morphological observations may be explained in terms of growth and/or mortality rate differences between the polluted and non-polluted sites. Although a variety of stressors may account for these adverse morphological patterns, our data suggest a close relationship with the soft tissue heavy metal content. Compared to soft tissue heavy metal levels that were measured in L. scabra along the same area in 1998, most metals, except for arsenic, chromium and iron have decreased dramatically.     

Comparison of two metal surveys by moss Tortula ruralis in Budapest, Hungary

Moss transplants of Tortula ruralis were used as active biomonitoring organisms as part of a monitoring study to assess the metals (Al, Cd, Cu, Cr, Fe, Ni, Pb, V and Zn) associated with ambient particles on mosses in Budapest, the capital town of Hungary. The moss samples were collected in a nature conservation area from a semi-arid sand grassland (Festucetum vaginatae danubiale), less than 1 month before transplantation. Moss cushions were exposed to pollution in Budapest during October–November 1993 and February–March 1994. In the study area, 16 sites were marked out as measuring sites, in accordance with the structure of the city. A similar stand was established in the Botanical Gardens of the Szent István University in Gödöll? as a control site. ICP-AES analysis of moss for metals showed the ability of Tortula ruralis to accumulate the metals under study. Control site showed lower impact in comparison to the other sites.     

An Effective Means of Biofiltration of Heavy Metal Contaminated Water Bodies Using Aquatic Weed Eichhornia crassipes

Various aquatic plant species are known to accumulate heavy metals through the process of bioaccumulation. World’s most troublesome aquatic weed water hyacinth (Eichhornia crassipes) has been studied for its tendency to bio-accumulate and bio-magnify the heavy metal contaminants present in water bodies. The chemical investigation of plant parts has shown that it accumulates heavy metals like lead (Pb), chromium (Cr), zinc (Zn), manganese (Mn) and copper (Cu) to a large extent. Of all the heavy metals studied Pb, Zn and Mn tend to show greater affinity towards bioaccumulation. The higher concentration of metal in the aquatic weed signifies the biomagnification that lead to filtration of metallic ions from polluted water. The concept that E. crassipes can be used as a natural aquatic treatment system in the uptake of heavy metals is explored.