Metal accumulation and sub-lethal effects of copper nanoparticles compared to copper sulphate in the shore crab, Carcinus maenas

New, emerging, metal-containing nanomaterials, including copper-nanoparticles (Cu NPs), open up a wide range of unanswered questions on fate, behaviour, chemistry and toxicity in the marine environment. Through a 7 day aquatic exposure of the shore crab Carcinus maenas to 200 μg L-1 and 1 mg L-1 Cu NPs, or 1 mg L-1 CuSO4, this study, the first of its kind, aims to ascertain differences in accumulation in target organs, Na+-Cu2+ interactions and Cu induced oxidative stress. Crabs were sampled at days 0, 4 and 7 for tissue trace metal analysis and biochemical analysis (Na+/K+-ATPase, thiobarbituric acid reactive substances (TBARS) and total glutathione (GSH)). By day 7, 54% mortality was recorded following the 1 mg L-1 CuSO4 exposure, compared to just 21% from the 1 mg L-1 Cu NPs exposed crabs. Statistically significant copper accumulations were seen in all gills taken from all Cu treatments at day 7 compared to controls. Delayed accumulations were observed in the hepatopancreas, and the lowest concentrations within the chela muscle. Anterior gills were identified as primary target organs for both, Cu NPs (1 mg L-1) and CuSO4, with mean Cu concentrations (± S.E.) of 1.2 ± 0.5 and 2.1 ± 0.8 mg L-1 respectively by the end of the experiment. Copper induced oxidative stress (TBARS), remained steady over time in crabs exposed to CuSO4, however, a time dependent decrease in TBARS was observed in Cu NP exposed crab. No change in total GSH was recorded for all treatments (including control) with mean levels of (± S.E.) 0.079 ± 0.0014 μM g-1. Overall, it is concluded that the accumulation and toxic effects of Cu NP is comparable to that of CuSO4, however, negative impacts may already occur at lower tissue Cu concentrations