Toxicokinetics of Zn and Cd in the earthworm Eisenia andrei exposed to metal-contaminated soils under different combinations of air temperature and soil moisture content

• Published in: Chemosphere (Oxford) 2018-04, Vol.197, p.26-32
• Main Authors: González-Alcaraz, M. Nazaret, Loureiro, Susana, van Gestel, Cornelis A.M.
• Format: Article
• Language: English
• Subjects: Animals; Bioaccumulation; Bioavailability; Cadmium - toxicity; Climate Change; Environmental Pollution; Global Warming; Heavy metals; Metals - toxicity; Metals, Heavy - toxicity; Mining wastes; Oligochaeta - drug effects; Oligochaeta - physiology; Soil - chemistry; Soil invertebrates; Soil Pollutants - analysis; Soil Pollutants - toxicity; Temperature; Toxicokinetics; Triazines; Water; Zinc - analysis; Zinc - toxicity
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2018.01.019

This study evaluated how different combinations of air temperature (20 °C and 25 °C) and soil moisture content (50% and 30% of the soil water holding capacity, WHC), reflecting realistic climate change scenarios, affect the bioaccumulation kinetics of Zn and Cd in the earthworm Eisenia andrei. Earthworms were exposed for 21 d to two metal-contaminated soils (uptake phase), followed by 21 d incubation in non-contaminated soil (elimination phase). Body Zn and Cd concentrations were checked in time and metal uptake (k1) and elimination (k2) rate constants determined; metal bioaccumulation factor (BAF) was calculated as k1/k2. Earthworms showed extremely fast uptake and elimination of Zn, regardless of the exposure level. Climate conditions had no major impacts on the bioaccumulation kinetics of Zn, although a tendency towards lower k1 and k2 values was observed at 25 °C + 30% WHC. Earthworm Cd concentrations gradually increased with time upon exposure to metal-contaminated soils, especially at 50% WHC, and remained constant or slowly decreased following transfer to non-contaminated soil. Different combinations of air temperature and soil moisture content changed the bioaccumulation kinetics of Cd, leading to higher k1 and k2 values for earthworms incubated at 25 °C + 50% WHC and slower Cd kinetics at 25 °C + 30% WHC. This resulted in greater BAFs for Cd at warmer and drier environments which could imply higher toxicity risks but also of transfer of Cd within the food chain under the current global warming perspective. •Climate change simulated by higher air temperature and lower soil moisture content.•Zn toxicokinetics in Eisenia andrei not affected by climate conditions.•Faster Cd kinetics in earthworms at higher air temperature and soil moisture content.•Cd kinetics at higher air temperature slowed down with decreasing soil moisture.•Higher Cd-BAFs in earthworms incubated under warmer and drier conditions.