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题名: 水环境中铜形态与其生物有效性/毒性关系及其预测模型研究
作者: 黄圣彪
学位类别: 博士
答辩日期: 2003
授予单位: 中国科学院研究生院
授予地点: 北京
导师: 王子健
关键词: 生物活性态铜([Cu*]) ; BLM ; 形态 ; Copper speciation ; 毒性 ; Toxicity ; [Cu*]
其他题名: Measurement and Prediction in the Toxic/ Bioavailabile Concentration of Copper in Natural Water
中文摘要:       在地表水水质标准的制定过程中,金属形态和生物有效性/毒性关系已经引起科学家和管理部门的广泛重视。然而在过去形态与毒性关系的研究中,化学分析或生物毒性测定往往是独立进行,在方法学上存在一些限制。首先,应用于形态分析方法技术的灵敏度和选择性尚不能满足实际工作的需要,所测定的“形态”还存在一定程度的模糊性。其次,生物试验往往持续较长时间,体系中金属的形态会发生变化。因此在金属形态与生物有效性研究中,势必需要发展具有更高灵敏度和更高选择性的形态分析方法,并和现有指标生物毒性测试的手段相结合。通过研究形态与生物毒性的关系可以为在形态的基础上建立新的水质标准提供依据。这种以生物效应为目的的形态分析或分类研究正是国际环境研究的热点。针对这一观点,本论文第一部分采用大型蚤、斜生栅藻、发光菌等毒性试验方法评价生物毒性,用化学平衡模式MINTEQAZ、微分脉冲阳极溶出伏安法分析形态分布特点,经统计处理建立了简单体系中铜形态与毒性的关系。结果表明:不同碱度(由HCO3-表示)或不同浓度的Cl-,EDTA和FA存在的模拟水体系中,铜对各种生物的毒性都不同程度的降低。通过分析得出初步结论:HCO3-,Cl-,EDTA和DOC与铜的络合形态在铜对三种水生生物的毒性试验中表现为无毒性特征。根据这一现象并假设测试体系中的电极有效态铜都是由无机铜络合形态组成,提出用生物活性态铜浓度(或者[Cu*])表征铜的毒性形态,[Cu*]等于由DAM-DPASV方法测定的电极有效态铜浓度减去铜与HcO3-和Cl-的络合形态,实验体系中铜形态分布用MINTEQ A2模型计算。在模拟水体系中,由咚矿〕和[Cu2+]表示的EC50值是一个常数,不随着HCO3-,Cr,EDTA和FA浓度的变化而变化,[Cu*]与铜的毒性(TP)之间呈很好的线性关系。对这一模型进行了实际应用,发现模型结果很好地解释了在官厅水库铜的毒性:这说明[Cu*]能够替代FIAM模型中的[Cu2+]进行铜对淡水藻、淡水发光菌和大型蚤毒性预测,通过[Cu*]预测得到的铜毒性(EC50或LC50)真实地反应了水化学特性对铜形态及其生物有效性/毒性的影响。本论文的第二部分内容是发展了生物配体模型(BLM,Biotic-Ligand Medel)。BLM模型被发展用于来评价水化学特性对金属生物有效性的影响。BLM模型实际上是对金属环境化学长期研究和认识的总结,阐述过去研究的优缺点,并对实际数据进行了验证。最初的BLM模型参数数据库可以用于淡水水域铜对鱼毒性的预测,但对于其它的生物这些参数还是相当匾乏。因此要想将BLM模型用于金属对其它生物毒性的预测,必须进行模型的校正和数据库的完善。我们以淡水藻作为模型生物,进一步发展了BLM模型的生物种类数据库。假设铜与藻细胞的作用首先是与细胞表面的物理活性位“-X-cell”,结合,将“-X-cell’,看作类似于鱼鳃粘膜表面的“生物基团”。根据络合滴定原理,通过实验测定藻细胞表面生物基团(或者BL)对铜的络合容量(CCB)和络合常数(logKβL)。通过几种铜形态(溶解态、细胞内结合态和细胞表面可交换结合态)与藻细胞生长抑制率的比较发现,细胞表面可交换铜形态(CuBL)的累积数量能够很好的表征铜对藻的毒性。在铜对藻细胞生长率的半抑制有效浓度(EC50)时,铜在细胞表面的可交换关键性累积量(LA50)为2.5*108μmol.cell-1,占细胞表面“生物基团,数量的43%。根据所获得参数,本论文以淡水藻为模型生物,进行了BLM模型对铜毒性预测能力的验证,发现在模拟水和官厅水库水中,BLM模型的预测值(EC50)和样品铜加标生物毒性测定值(Ec50)具有很好的一致性。论文还根据文献提供的铜对大型蚤半致死有效浓度(LC50)时,大型蚤铜的累积量(LA50),运用BLM模型进行了官厅水库中铜对大型蚤毒性的预测,预测值和样品生物毒性试验测定值也表现出很好的一致性。同时,论文对于发展的BLM模型在特定点水质标准修改中的应用能力进行了初步的探讨。
英文摘要:       Current water quality standards and risk assessment procedures for metals are redominantly based on the total or dissolved metal concentrations. However, there is tensive evidence that neither total nor dissolved aqueous metal concentrations are good redictors of metal bioavailability and toxicity. Cu toxicity to freshwater organisms has een shown to be dependent on a variety of ambient water quality characteristics. In this dissertation, the concentration of labile Cu was measured by differential pulse lodic stripping voltammetry with a double acidification method (DAM-DPASV) and was sed to predict the toxicity of Cu on the alga (S. oblignus), D. magna and luminescent acterium (Vibrio-qinghaiensisNov.-Q67). The influences of alkalinity, chloride, and ifferent concentrations of Ethylene Diamine Tetraacetic Acid (EDTA) and fulvic acid (FA) n the labile concentration and toxicity of Cu were investigated in reconstituted water and inatural water. The results showed that chloride and alkalinity did not affect labile Cu jncentration, but decreased the toxicity of Cu to organisms in the concentration range bserved in fresh water. The influences of alkalinity and chloride could be modeled if u-carbonate complexes and Cu-chloride complexes were considered as non-toxic species, rganic complexes of Cu with EDTA and FA did not contribute either to the labile mcentration of Cu or to the toxicity of Cu on organisms. The growth inhibition of Cu on rganisms in natural water could be predicted by using the bioavailable concentration of CU. or [Cu*], which could be calculated from the labile Cu concentration using the DAM-DPASV method and the concentrations of Cu-carbonate and Cu-chloride complexes obtained from the MINTEQ A2 model. In the content, the Biotic Ligand Model (BLM), well developed to explain and predict the toxic effects of water chemistry on the toxicity of copper to rainbow trout, fathead minnow and are developing for D. magna, was developed and applied to predict toxic effects of Cu to freshwater alga. Cu toxicity to alga varies over a range of EDTA, DOC, alkalinity and chloride. Higher content of EDTA, DOC, alkalinity and chloride linearly increased the 96-h EC50 (as the total Cu), supporting the concept of complexes of these ligands with Cu so as to reduce the chance of Cu adsorbed on the active sites at the organism-water interface. Based on the BLM concept, we developed a methodology to estimate stability constants and complexation capacity (or BL, which equals to concentration of binding sites on the single cell) for the Cu binding to biotic ligands on algal cell. Following values were obtained: log KBL = 5.8, and CCBL=5.74 * 10-8 umol'cell" . The critical accumulation of Cu EC50 (or LA50) was determined to be 2.5 * 10-8 limol cell-1 corresponding to the dissolved Cu EC50, and the conclusion that the average 43% of biotic ligand sites need to be occupied by Cu to induce a 50% acute effect for alga after 96-h exposure has been made. Using the estimated constants, we examine the key assumption that underlies the BLM, whose toxicity can be defined as accumulation of copper at the physiological activity sites (or biotic ligand) on the alga cell membrane at or above a critical threshold concentration. Meanwhile, in the absence of any specific information about the natural of the biotic ligand in D. Magna, the adjust of the LA50 is the simplest means of adapting the fish parameter set. The initial BLM was developed that can predict acute Cu toxicity to alga and D. Magna as a function of water characteristics. After validation with reconstituted and natural waters, the developed model will support efforts to predict Cu EC50s for use in determinations of Water-Effect-Ratio (WER). The presented methodology can easily be applied for BLM development for prediction of Cu toxicity to other organisms.
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/34945
Appears in Collections:环境水质学国家重点实验室_学位论文

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Recommended Citation:
黄圣彪. 水环境中铜形态与其生物有效性/毒性关系及其预测模型研究[D]. 北京. 中国科学院研究生院. 2003.
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