Department of Environmental Geochemistry, Fluminense Federal University, Outeiro São João Baptista, s/n., Centro, 24020-007 Niterói, RJ, Brazil.
ECT Oekotoxikologie GmbH, Boettgerstr. 2-14, D-65439 Flörsheim/Main, Germany.
Environ Res. 2017 May;155:365-372. doi: 10.1016/j.envres.2017.03.005. Epub 2017 Mar 20.
Soil provides many ecosystem services that are essential to maintain its quality and healthy development of the flora, fauna and human well-being. Environmental mercury levels may harm the survival and diversity of the soil fauna. In this respect, efforts have been made to establish limit values of mercury (Hg) in soils to terrestrial fauna. Soil organisms such as earthworms and enchytraeids have intimate contact with trace metals in soil by their oral and dermal routes, reflecting the potentially adverse effects of this contaminant. The main goal of this study was to obtain Hg critical concentrations under normal and extreme conditions of moisture in tropical soils to Enchytraeus crypticus to order to assess if climate change may potentiate their acute and chronic toxicity effects. Tropical soils were sampled from of two Forest Conservation Units of the Rio de Janeiro State - Brazil, which has been contaminated by Hg atmospheric depositions. Worms were exposed to three moisture conditions, at 20%, 50% and 80% of water holding capacity, respectively, and in combination with different Hg (HgCl) concentrations spiked in three types of tropical soil (two natural soils and one artificial soil). The tested concentrations ranged from 0 to 512mg Hg kg dry weight. Results indicate that the Hg toxicity is higher under increased conditions of moisture, significantly affecting survival and reproduction rate.
土壤提供了许多生态系统服务，对维持其质量以及动植物和人类的健康发展至关重要。环境中的汞水平可能会危害土壤动物的生存和多样性。在这方面，已经努力为土壤中的汞（Hg）设定了对陆地动物的限值。土壤生物，如蚯蚓和真蚓科，通过口腔和皮肤途径与土壤中的痕量金属密切接触，反映出这种污染物的潜在不利影响。本研究的主要目的是在正常和极端水分条件下获得热带土壤中对真蚓科 Enchytraeus crypticus 的 Hg 临界浓度，以评估气候变化是否可能增强其急性和慢性毒性效应。从巴西里约热内卢州的两个森林保护单位采集了热带土壤样本，这些土壤受到 Hg 大气沉降的污染。将蠕虫暴露于 20%、50%和 80%的水分保持能力三种水分条件下，并与三种热带土壤（两种天然土壤和一种人工土壤）中添加的不同 Hg（HgCl）浓度组合。测试浓度范围为 0 至 512mg Hg kg 干重。结果表明，在水分增加的条件下，Hg 的毒性更高，显著影响了生存和繁殖率。
