Copper accumulation and toxicity in earthworms exposed to CuO nanomaterials: Effects of particle coating and soil ageing.

Engineered nanomaterials (ENMs) may be functionalised with a surface coating to enhance their properties, but the ecotoxicity of the coatings and how hazard changes with ageing in soil is poorly understood. This study determined the toxic effect of CuO ENMs with different chemical coatings on the earthworm (Eisenia fetida) in fresh soil, and then after one year in aged soil. In both experiments, earthworms were exposed for 14 days to the CuO materials at nominal concentrations of 200 and 1000 mg Cu kg dry weight and compared to CuSO.

The acute toxicity of thallium to freshwater organisms: Implications for risk assessment.

The acute toxicity of Tl(I) to the microalga, Pseudokirchneriella subcapitata, the planktonic crustaceans, Daphnia magna and Daphnia pulex, and early-life stage of the zebrafish, Danio rerio, has been studied according to OECD protocols. Toxicological end-point concentrations for the microalga ranged from 17 μg l(-1) for a 72 h EyC25 (yield inhibition) to 80 μg l(-1) for a 72 h ErC50 (growth inhibition). Daphnia were less sensitive to Tl, with 48 h EC50s of about 1000 μg l(-1) and 1200 μg l(-1) for D.

Distributions and concentrations of thallium in surface waters of a region impacted by historical metal mining (Cornwall, UK).

Thallium is a highly toxic heavy metal whose concentrations and distributions in the aquatic environment are poorly defined. In this study, concentrations of aqueous and total Tl have been measured in water samples from a variety of rivers and effluents (the latter related to historical metal mining) in the county of Cornwall, SW England. Aqueous concentrations ranged from about 13 ng L(-1) in a river whose catchment contained no metal mines to 2,640 ng L(-1) in water abstracted directly from an abandoned mine shaft.