Influence of clay content on bioavailability of copper in the earthworm Eisenia fetida

• Published in: Ecotoxicology and environmental safety Vol. 73; no. 3; pp. 407 - 414
• Main Authors: Owojori, Olugbenga J., Reinecke, Adriaan J., Rozanov, Andrei B.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.03.2010
• Subjects: Aluminum Silicates - chemistry; Aluminum Silicates - pharmacokinetics; Animals; Bioavailability; Biological Availability; Body Weight - drug effects; Calcium Chloride - chemistry; Chelating Agents - chemistry; Clay; Clay (material); Control; Copper; Copper - analysis; Copper - chemistry; Copper - pharmacokinetics; Eisenia fetida; Environmental Monitoring; Extraction; Longevity - drug effects; Mortality; Oligochaeta - chemistry; Oligochaeta - growth & development; Oligochaeta - metabolism; Partitioning; Pentetic Acid - chemistry; Reproduction - drug effects; Risk Assessment; Soil Pollutants - analysis; Soil Pollutants - chemistry; Soil Pollutants - pharmacokinetics; Toxicity; Worms; Clay; Bioavailability; Eisenia fetida; Partitioning; Copper; Risk assessment
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2009.03.017

We investigated the effect of clay content on the bioavailability of copper to the earthworm Eisenia fetida, in the laboratory for 28 days using OECD artificial soil adjusted to 5%, 20% and 40% clay. Mortality, growth, cocoon production and internal copper concentrations were assessed in worms, and total, DTPA and CaCl 2 extractable copper in the substrates were also determined. The results showed that with increased clay content, there was significant reduction in internal Cu concentration of worms as well as toxicity of copper as shown by data for growth and mortality. However, internal copper concentrations of worms could not explain fully the observed toxicity in this study probably because of Cu regulation. Among the three extraction methods, DTPA extraction revealed the strongest relationship between partitioning and toxicity of Cu in this study. DTPA extract is thus a promising surrogate measure of bioavailability of Cu to earthworms. It is concluded that clay content has significant influence on the bioavailability of copper to earthworms and other similar species.