Phytoavailability and potential transfer of Pb from a salt-affected soil to Atriplex verucifera,Salicornia europaea and Chenopodium album

The phytoavailability and potential transfer of Pb to Atriplex verucifera, Salicornia europaea and Chenopodium album in two calcareous soils with different salinity/sodicity were compared. The soils were spiked with 0, 250, 500 and 1000 mg Pb kg^?1 soil. Plant shoots were harvested and analysed for total Pb after they had been grown in the contaminated soils. Visual MINTEQ 3.0 was used to calculate the speciation of soluble Pb in the experimental soils. Results showed that although the concentrations of 1 M NH₄NO₃-extractable Pb were relatively similar, speciation of Pb in the soils were not the same. Salicornia europea was found to be the most salinity/sodicity-tolerant plant. When the plants were grown in non-saline soil, the Pb tolerance of the three plants was as follows: A. verucifera > C. album >S. europea, whereas in saline (sodic) soil, Pb tolerance was in the order S. europea > C. album > A. verucifera. Lead phytotoxicity to A. verucifera and C. album was higher in the saline soil, whereas for S. europea, Pb toxicity was higher in the non-saline soil. It could be concluded that the phytoavailability of Pb and its interactions with plants are widely dependent on soil salinity level and type of plant.     

健康风险评估方法在中国重金属污染中的应用及暴露评估模型的研究进展

经济的快速发展导致中国环境质量日趋恶化.随着健康意识的增强,人们越来越重视污染物暴露人群的健康风险评估.与其他污染物相比,重金属污染区域广,重金属暴露人群多且集中.为了研究重金属暴露条件下人群的健康风险,USEPA 模型、统计模型、地理信息系统、可给性研究的方法已被中国不同学者应用.暴露评估模型作为污染物暴露人群健康风险评估的主要环节,国外的研究已经比较成熟,但相关研究在中国还处于空白阶段.对中国近年来在城市表层土壤（灰尘）、矿区土壤、膳食、地下水和饮用水、大气颗粒物进行重金属风险评估中应用的健康风险评估方法,进行了归纳和评述,并对欧美常用暴露评估模型：环境暴露评估模型、膳食暴露评估模型进行了介绍.中国健康风险评估工作起步晚,在评估的各环节均存在很大缺陷.随着新技术的发展以及人群对环境健康风险认识的深化,健康风险评估将成为中国热门研究领域之一.污染的环境行为、剂量一效应关系、模型、风险信息等方面,将是未来中国健康风险评估研究的重点.     

Metals in the sediment and liver of four fish species from different trophic levels in Tisza River,Serbia

In aquatic environments metals originate from various natural and anthropogenic sources. The degree of contamination in fish tissues depends on the pollutant, fish species, their mode of feeding, sampling site and trophic level. This study presents concentrations of Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Sr and Zn in sediment and liver of four ecologically different fish species: piscivorous northern pike (Esox lucius L.), benthivorous sterlet (Acipenser ruthenus L.) and silver bream (Brama brama L.), and omnivorous common carp (Cyprinus carpio L.). Fish were caught at four sites along the stretch of the River Tisza in Serbia during October 2010. The concentrations of metals have been assessed using the inductively coupled plasma – optical emission spectrometry. Results revealed that metals with the highest values in sediment and fish samples were Al and Fe, respectively and sometimes concentrations of Zn are in the same order of magnitude as Fe concentrations. The highest concentration of metals was recorded in omnivorous common carp.     

Reuse of heavy metal-accumulating Cynondon dactylon in remediation of water contaminated by heavy metals

Phytoremediation technology is regarded as a simple and efficient way to remove heavy metals from contaminated soil. A reasonable disposal of metal hyperaccumulators is always and resource-saving. The a major issue in waste reuse heavy metal-accumulating Cynondon dactylon （L.） was investigated where heavy metals were desorbed by a facile acid-treatment. The result indicated that more than 90% of heavy metals （Zn, Pb and Cu） was extracted from Cynondon daetylon with 0.2 mmol· L^-1 HCl. The plant residue was used to adsorb heavy metals ions. The adsorption fitted the Langmuir isotherm model with the saturation adsorption capacity of 9.5 mg·g^-1 Zn^2＋, 36.2 mg·g^-1 Pb2＋ and 12.9 mg·g^-1 Cu^2＋, and the surface eomplexation and the backfilling of heavy metal imprinting cavities existed simultaneously during the adsorption. The treatment of wastewaters indicated that the plant residue exhibited a high removal rate of 97% for Cu. Also, the material could be recycled. The method offers a new disposal approach for heavy metal hyperaccumulator.     

微生物对沉积物主要化学组分吸附重金属能力的影响

通过松花江水中微生物与铁、锰氧化物和腐殖酸形成的复合物质的比表面积及吸附Pb、Cd能力的分析,探讨微生物对沉积物中主要化学组分理化性质的影响及机理.结果表明:锰氧化物的比表面积大于铁氧化物和腐殖酸,与微生物结合后比表面积均不同程度增加. 固体物质的比表面积与吸附Pb和Cd的能力并不完全一致,与它们对重金属的吸附机制不同有关.复合物质的的吸附能力并不符合加和模型,微生物的存在掩盖了铁、锰氧化物和腐殖酸表面部分官能团,造成了复合物质的吸附量小于各组分的吸附量之和.     

Genotoxic effects of metals on human salivary gland tissue and lymphocytes as detected by the Comet assay

The etiology of salivary gland malignancies still remains unclear. Metal compounds are of special interest since they show ubiquitous presence in the environment, are present in many working places, and are accepted (co-)carcinogens in some other malignancies. Metals enter the body as xenobiotics by inhalation or ingestion. This study investigated the genotoxic potential of sodium dichromate (Na₂Cr₂O₇), nickel sulfate (NiSO₄), cadmium sulfate (CdSO₄) and zinc chloride (ZnCl₂) on human salivary gland cells and lymphocytes. Macroscopically healthy tissue of salivary glands was harvested from 46 patients during surgery and isolated to single cells by enzymatic digestion. The cells were incubated with Na₂Cr₂O₇, NiSO₄, CdSO₄ or ZnCl₂. Na₂Cr₂O₇ was also incubated in combination with the other metal compounds listed. Carcinogenic and co-carcinogenic effects of cadmium were tested by incubation with Na₂Cr₂O₇ and consecutive repair intervals. DNA damage and repair were evaluated by the Comet assay, determining DNA-strand breaks. The extent of damage was quantified using a digital analysis system. Na₂Cr₂O₇ produced significantly enhanced DNA-strand breaks in human salivary gland tissue and lymphocytes. All other metal compounds exerted no damaging effect on both cell types. Co-incubation of Na₂Cr₂O₇ with the other metals revealed a significant additive effect only for CdSO₄. Specific analysis of the influence of cadmium showed a reduction of DNA-repair after Na₂Cr₂O₇-induced strand breaks in salivary gland cells. This study provides evidence that exposure to distinct metals may significantly contribute to malignant salivary gland tumors. In consequence, further studies as epidemiological and toxicological data are warranted to determine the role of distinct metals as potential (co-) carcinogens.     

Use of different soft tissues of Perna viridis a s biomonitors of bioavailability and contamination by heavy metals (Cd,Cu, Fe,Pb, Ni,and Zn) in a semi-enclosed intertidal water,the Johore Straits

Green-lipped mussels, Perna viridis, were collected from the eastern and western parts of the Johore Straits in September 2004 and January 2005. Based on the heavy metal concentrations in the different soft tissues (gonad, foot, mantle, gills, muscle, and remaining soft tissues) of these mussel samples, the eastern part of the Johore Straits (which is divided into two portions by a causeway), recorded higher levels of bioavailability and contamination by Cd, Cu, Fe, Ni, and Zn when compared to the western part, while Kg. Pasir Puteh in the eastern part was found to record the highest bioavailability and contamination by heavy metals. The use of different soft tissues of P. viridis as biomonitors of bioavailability and contamination by Cd, Cu, Fe, Pb, Ni, and Zn in the semi-enclosed Johore Straits is proposed, since erroneous results due to spawning and the problem of defecation before dissection could be overcome. Hence, a more accurate interpretation of the bioavailability and contamination by heavy metals in coastal waters could be obtained. To our knowledge, this is the most detailed study on the bioavailability and contamination of heavy metals in the Johore Straits on the Malaysian side of the waterway carried out by using the different soft tissues and metal distribution based on the Mussel Watch approach.     

The correlation of total and extractable heavy metals from soil and domestic sewage sludge and their transfer to maize ( Zea mays L.) plants

A study to understand the mobility and transport of heavy metals (HMs) from soil and soil amended with sewage sludge to maize plants was carried out. The total and ethylenediaminetetraaceticacid (EDTA)-extractable HMs in agricultural soil and untreated domestic sewage sludge samples, and the correlation between the total and extractable metals in soil and sewage sludge were carried out. Pot experiments were performed to study the transfer of HMs to maize grains, grown in soil (control) and in soil amended with sewage sludge (test samples). The total and extractable HMs in soil, sewage sludge, and maize grains were analysed by FAAS/ETAAS (flame atomic absorption spectrometer/electrothermal atomic absorption spectrometer) after digestion in microwave oven. Statistically significant correlations were obtained between the total contents of Cu, Cd, As and their respective extractable fractions in soil, while in domestic wastewater sludge (DWS) the better correlation was observed only for Ni and Cd. The edible part of maize plants (grains) from test samples presented high concentration of Zn, Pb, Ni, Cd, Cu, As, and Cr concentrations (80.7–85.6, 3.8–3.95, 2.35–2.5, 0.75–0.82, 3.21–3.29, 0.23–0.27, and 0.22–0.29?mg?kg^?1, respectively). Good correlations were found between metals in exchangeable fractions of both soil and DWS and total metals in control and test samples of maize grains. The transfer factor of all HMs from DWS to maize grains was also determined.     

Determination of types of interactions exhibited by binary mixtures of heavy metals tested against the hermit crab,Clibanarius africanus

Single and joint action toxicity of heavy metal compounds (ZnCO₃, CuSO₄ and CdSO₄) were carried out against the hermit crab, Clibanarius africanus in laboratory bioassays. On the basis of 96?h LC₅₀ values, CuSO₄ (96?h LC₅₀?=?0.03?mM) was found to be the most toxic followed by CdSO₄ and ZnCO₃ (96?h LC₅₀?=?0.24?mM) in decreasing order of toxicity. The evaluation of the metal compounds in mixtures of ZnCO₃–CuSO₄, ZnCO₃–CdSO₄ and CdSO₄–CuSO₄ in pre-defined molar ratios revealed that interactions between Zn–Cu and Zn–Cd test mixtures were in conformity with the models of antagonism (reduction in toxicity of constituent metals). The synergistic ratios (S.R.s) and relationship between observed/predicted 96?h LC₅₀ values (relative toxic unit, RTU) were consistently below 1, indicating antagonistic interactions. Analysis using isobolograms also indicated the interactions between the mixture components to be antagonistic. However, with regards to CdSO₄–CuSO₄ test mixtures, the interactions between these metals were mainly in conformity with the model of synergism. The S.R. and RTU values were largely above 1, indicating synergistic interactions. The importance of the joint action evaluations for the management and protection of aquatic ecosystems, particularly in the setting up of water quality criteria was discussed.     

Speciation of heavy metals in Albanian coastal sediments

This article presents results on heavy metal (Fe, Mn, Cr, Ni, Cu, Cd, Pb and Zn) speciation in the coastal sediments of Albania. Sediment samples were collected within the framework of the activities of the Interreg Italia–Albania Project, carried out in the Southern Adriatic Sea in 2000–01. This study shows that Albanian coastal sediments are highly influenced by river input, as the decreasing concentrations from coast to offshore confirm. Pb represents an exception of the general trend; meteoric inputs are prevalent for this metal. Ni, Cr, Fe, Zn and Cu correlate significantly and positively in the entire area, indicating a common origin for these metals in the analyzed sediments. All metals result mostly associated to the most refractory phases, which constitute up to 80% of the total concentration. Nevertheless a recent input of Cr, Ni, Cu and Mn can be observed, as the result of mining and industrial activities, in some selected areas, such as the Drin Bay and Durres. Their high concentration in the bioavailable phase can determine toxic effect upon biota.