Despite concerns about the significant toxicity of copper pyrithione (CuPT) at environmental concentrations, effects of CuPT on benthic organisms have received little attention. Here, we analyzed the detrimental effects of CuPT at sublethal concentrations (1/50, 1/20, and 1/10 of the 96 h-LC50 value) for 14 days in the marine polychaete Perinereis aibuhitensis. Reduced burrowing activity and significantly decreased the acetylcholinesterase activity in response to relatively high concentrations of CuPT were identified as CuPT-triggered cholinergic inhibition. The lipid peroxidation marker, malondialdehyde levels were dosedependently increased, whereas intracellular glutathione was depleted by relatively high concentrations. In the CuPT-treated polychaete, significant fluctuations in the enzymatic activities of the antioxidant defense system (catalase, superoxide dismutase, glutathione reductase, and glutathione peroxidase) were observed with significantly modulated glutathione S-transferase activity. These results indicate that even sublethal levels of CuPT would have detrimental effects on the health status of the marine polychaete.

Introduction
Materials and Methods
    1. Marine polychaete
    2. Exposure
    3. Burrowing and AChE activity
    4. Measurement of antioxidant parameters
Results
    1. Effects on the burrowing ability and AChEactivity
    2. Effects on the MDA and GSH contents
    3. Effects on the antioxidant defense system
    4. Effects on the GST activity
Discussion
Conclusions

• Md. Niamul Haque(Department of Marine Science, College of Natural Sciences, Incheon National University, Incheon 22012, Korea, Research Institute of Basic Sciences, Incheon National University, Incheon 22012, Korea)
• Jae-Sung Rhee(Department of Marine Science, College of Natural Sciences, Incheon National University, Incheon 22012, Korea, Research Institute of Basic Sciences, Incheon National University, Incheon 22012, Korea, Institute of Green Environmental Research Center, Incheon 21999, Korea, Yellow Sea Research Institute, Incheon 22012, Korea ) Corresponding author