摘要:
污染物的剂量-效应关系是生态毒理学的重要基础。在剂量-效应关系中,EC10(10%有效抑制浓度)是建立基于风险的环境质量基准值的基础,但有关污染物生态效应的研究报导中多数采用毒性阈值EC50(半数抑制浓度),如何将EC50转化为EC10是建立污染物环境质量基准急需解决的问题。利用log-logistic拟合了中国17种代表性土壤中大麦、西红柿、小白菜3种植物的铜和镍剂量-效应曲线,获得了不同土壤中铜、镍剂量-效应曲线中段的斜率(b值),并依据计量-效应曲线获得3种植物在不同土壤中的铜、镍EC10和EC50值。结果表明:铜和镍的剂量-效应曲线b值受土壤性质显著影响,但不同物种间的变化较小,大麦、西红柿及小白菜的铜、镍剂量-效应曲线b值绝对值的平均值分别接近于6.0和7.0。利用来自中国土壤的毒理学数据建立的铜和镍EC50和EC10单因子量化模型能较为准确地通过铜和镍EC50值预测其EC10值,其量化模型的决定系数分别为0.704和0.799,当分别考虑土壤pH和有机碳(OC)的影响时,铜和镍的EC10量化模型的决定系数分别提高至0.730和0.885。土壤中铜、镍EC10与EC50量化关系的建立可为中国土壤中铜、镍的风险评价及相关标准的制定提供更多的数据基础。
关键词:
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土壤
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剂量-效应曲线
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铜
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镍
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毒性阈值
Abstract:
The dose-response relationship is an important part of ecotoxicology. Different effective concentrations causing inhibition for chemicals could be derived based on the dose-response relationship. The effective concentration causing 10% inhibition (EC10) values are the basis for establishing risk-based environmental quality criteria, while most of the thresholds reported in the research about ecotoxicity were the effective concentration causing 50% inhibition (EC50) values. To find out the quantative relationship of different ecotoxicity thresholds is a key issue needed to be addressed for deriving environmental quality criteria. In this paper, the dose-response curves of copper and nickel to barley root elongation, tomato and bok choy growth in 17 Chinese representative soils were fitted with log-logistic functions. The slopes (b) of the curves were obtained and the EC10 and EC50 values for the three plants in different soils were derived based on dose-response curves. The results showed that the soil properties affected the b values significantly. The b values for copper dose-response curves of barley, tomato and bok choy were in the range of 3.9~11.5, 2.7~12.1and 3.3~13.5, respectively. The b values for nickel dose-response curves of the three plants were in the range of 4.1~10.4、4.0~14.8 and 1.8~14.8, respectively. The b values for copper and nickel of the three plants were generally similar with an average mean value of 6.0 and 7.0 which implied that the variation of b value for a given toxicant in different plant species was not significant. The quantitative equations of EC10 and EC50 for copper and nickel were obtained based on ecotoxicity data from Chinese soils. The predictive models with the determination coefficient (R2) of 0.704 and 0.799, respectively, could predict EC10 values for copper and nickel based on EC50 values accurately. When taking into account the effect of pH in copper EC10 predictive model and organic carbon (OC) in nickel EC10 predictive model, the determination coefficient of the models increased up to 0.730 and 0.885, respectively. The quantitative equations of EC10 and EC50 for copper and nickel will provide more data basis for the risk assessment and the establishment of related soil standards.
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