Mercury critical concentrations to Enchytraeus crypticus (Annelida: Oligochaeta) under normal and extreme conditions of moisture in tropical soils – Reproduction and survival

• Published in: Environmental research 2017-05, Vol.155, p.365-372
• Main Authors: Buch, Andressa Cristhy, Schmelz, Rüdiger M., Niva, Cintia Carla, Correia, Maria Elizabeth Fernandes, Silva-Filho, Emmanoel Vieira
• Format: Article
• Language: English
• Subjects: Animals; Brazil; Climate Change; Ecotoxicity; Enchytraeids; Environmental contamination; Environmental Monitoring; Forest soils; Hydrogen-Ion Concentration; Lethal Dose 50; Mercury - analysis; Mercury - toxicity; No-Observed-Adverse-Effect Level; Oligochaeta - drug effects; Reproduction - drug effects; Soil - chemistry; Soil mesofauna; Soil Pollutants - analysis; Soil Pollutants - toxicity; Trace metals; Tropical Climate; Water - analysis
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2017.03.005

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 (HgCl2) 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−1 dry weight. Results indicate that the Hg toxicity is higher under increased conditions of moisture, significantly affecting survival and reproduction rate. [Display omitted] •Mercury toxicity was investigated in three moisture levels in tropical soils.•LC50 and EC50 values expressed Hg critical levels to enchytraeids.•Mercury toxicity to E. crypticus was higher in natural than artificial soils.•Extreme soil moisture intensified mercury toxicity responses to E. crypticus.