Sample Bradley E, Fairbrother Anne, Kaiser Ashley, Law Sheryl, Adams Bill
Ecological Risk, Rancho Murieta, California, USA.
Environ Toxicol Chem. 2014 Oct;33(10):2386-98. doi: 10.1002/etc.2675. Epub 2014 Aug 22.
Ecological soil-screening levels (Eco-SSLs) were developed by the United States Environmental Protection Agency (USEPA) for the purposes of setting conservative soil screening values that can be used to eliminate the need for further ecological assessment for specific analytes at a given site. Ecological soil-screening levels for wildlife represent a simplified dietary exposure model solved in terms of soil concentrations to produce exposure equal to a no-observed-adverse-effect toxicity reference value (TRV). Sensitivity analyses were performed for 6 avian and mammalian model species, and 16 metals/metalloids for which Eco-SSLs have been developed. The relative influence of model parameters was expressed as the absolute value of the range of variation observed in the resulting soil concentration when exposure is equal to the TRV. Rank analysis of variance was used to identify parameters with greatest influence on model output. For both birds and mammals, soil ingestion displayed the broadest overall range (variability), although TRVs consistently had the greatest influence on calculated soil concentrations; bioavailability in food was consistently the least influential parameter, although an important site-specific variable. Relative importance of parameters differed by trophic group. Soil ingestion ranked 2nd for carnivores and herbivores, but was 4th for invertivores. Different patterns were exhibited, depending on which parameter, trophic group, and analyte combination was considered. The approach for TRV selection was also examined in detail, with Cu as the representative analyte. The underlying assumption that generic body-weight-normalized TRVs can be used to derive protective levels for any species is not supported by the data. Whereas the use of site-, species-, and analyte-specific exposure parameters is recommended to reduce variation in exposure estimates (soil protection level), improvement of TRVs is more problematic.
美国环境保护局（USEPA）制定了生态土壤筛选水平（Eco-SSLs），目的是设定保守的土壤筛选值，可用于在特定场地消除对特定分析物进行进一步生态评估的必要性。野生动物的生态土壤筛选水平代表了一种简化的饮食暴露模型，该模型根据土壤浓度求解，以产生等于未观察到不良反应毒性参考值（TRV）的暴露量。对6种鸟类和哺乳动物模型物种以及已制定Eco-SSLs的16种金属/类金属进行了敏感性分析。模型参数的相对影响表示为当暴露量等于TRV时在所得土壤浓度中观察到的变化范围的绝对值。使用方差秩分析来识别对模型输出影响最大的参数。对于鸟类和哺乳动物，土壤摄入量总体变化范围最广，尽管TRVs始终对计算出的土壤浓度影响最大；食物中的生物可利用性始终是影响最小的参数，尽管它是一个重要的特定场地变量。参数的相对重要性因营养级而异。土壤摄入量在食肉动物和食草动物中排名第二，但在食虫动物中排名第四。根据所考虑的参数、营养级和分析物组合的不同，呈现出不同的模式。还以铜作为代表性分析物详细研究了TRV选择方法。数据不支持通用的体重标准化TRVs可用于推导任何物种的保护水平这一基本假设！虽然建议使用特定场地、物种和分析物的暴露参数来减少暴露估计值（土壤保护水平）的变化，但TRVs的改进更成问题。
