Ecological soil quality standards for lead (Pb) that account for soil Pb bioavailability have not yet been derived. We derived such standards based on specific studies of the long-term bioavailability and toxicity of Pb to soil organisms and a compilation of field data on the bioaccumulation of Pb in earthworms. Toxicity thresholds of Pb to plants, invertebrates, or microorganisms vary over more than 2 orders of magnitude, and the lowest values overlap with the range in natural Pb background concentrations in soil. Soils freshly spiked with Pb²⁺ salts exhibit higher Pb bioavailability and lower toxic thresholds than long-term aged and leached equivalents. Comparative toxicity tests on leaching and aging effects suggest using a soil Pb threshold that is 4.0 higher, to correct thresholds of freshly spiked soils. Toxicity to plants and earthworms, and microbial N-transformation and bioaccumulation of Pb in earthworms increase with decreasing effective cation exchange capacity (eCEC) of the soil, and models were derived to normalize data for variation of the eCEC among soils. Suggested ecological quality standards for soil expressed as total soil Pb concentration are lower for Pb toxicity to wildlife via secondary poisoning compared with direct Pb toxicity to soil organisms. Standards for both types of receptors vary by factors of approximately 4 depending on soil eCEC. The data and models we have collated can be used for setting ecological soil quality criteria for Pb in different regulatory frameworks. Environ Toxicol Chem 2021;40:1950–1963. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

中文翻译：

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土壤中铅的生物有效性和生态毒性：对制定生态土壤质量标准的意义

尚未得出说明土壤 Pb 生物有效性的铅 (Pb) 生态土壤质量标准。我们基于对铅对土壤生物的长期生物利用度和毒性的具体研究以及对蚯蚓体内铅生物积累的现场数据的汇编得出了这些标准。铅对植物、无脊椎动物或微生物的毒性阈值变化超过 2 个数量级，最低值与土壤中天然铅背景浓度的范围重叠。新添加 Pb ^2+的土壤盐比长期老化和浸出的盐表现出更高的铅生物利用度和更低的毒性阈值。浸出和老化效应的比较毒性试验表明，使用高于 4.0 的土壤 Pb 阈值来校正新加标土壤的阈值。对植物和蚯蚓的毒性，以及蚯蚓体内的微生物氮转化和铅的生物积累随着土壤有效阳离子交换容量 (eCEC) 的降低而增加，并推导出模型以标准化土壤间 eCEC 变化的数据。与铅对土壤生物的直接毒性相比，通过二次中毒对野生动物的铅毒性建议以土壤总铅浓度表示的土壤生态质量标准较低。两种受体的标准因土壤 eCEC 而异，大约为 4 倍。环境毒物化学2021；40:1950–1963。© 2021 作者。Wiley Periodicals LLC 代表 SETAC 出版的Environmental Toxicology and Chemistry 。