Ecotoxicological Study On Hydroides Elegans Exposed To Metal Pyrithione

In recent years,the problem of marine biofouling is becoming increasingly serious as the constantly intensified exploitation of marine resources and the rapid development of various maritime activities.In order to deal with this problem,the employment of marine antifouling agents greatly increased,the yield and application of copper pyrithine(CuPT)and zinc pyrithine(ZnPT)have been dramatically increased,this further increases the amount of CuPT and ZnPT in marine environment,it will cause a potential threat for the marine ecosystem and human health.At present the toxic effects of metal pyrithione on marine species are largely unknown in the South China Sea,it is necessary to conduct a comprehensive and systematic study of their ecotoxicity.As a worldwide fouling polychaete,Hydroides elegans is widely distributed in some tropical and subtropical seas.In this study,we studied the response of gamete,larvae and adult of Hydroides elegans to metal pyrithione.The main research content includes median inhibitory concentration(IC50),median lethal concentration(LC50),antioxidant enzyme system,glutathione,lipid peroxidation,DNA damage.1.IC50:The sperm or egg of Hydroides elegans were exposed to CuPT and ZnPT for 20 minutes respectively,and then test the fertilization.For sperm and egg the values of IC50 for CuPT were 19.49 μg/L and 88.44 μg/L,while the values of ICso for ZnPT were 36.74 μg/L and 159.59 μg/L respectively.2.LC50:We compared the response of 24-hour trochophore and 72-hour metatroch larvae to CuPT and ZnPT within 24 h and 48 h exposure period,respectively.For 24-hour larvae the values of LC50 for CuPT were 7.35 μg/L(24 h)and 5.00 μg/L(48 h),the values of LC50 for ZnPT were 8.57 μg/L(24 h),6.67 μg/L(48 h);while for 72-hour larvae the values of LC50 for CuPT were 8.57 μg/L(24 h)and 5.87 μg/L(48 h),the values of LC50 for ZnPT were 12.03 μg/L(24 h)and 8.07μg/L(48 h).3.Antioxidant enzyme:With the extension of exposure time,the SOD activity increased first then decline when exposed to CuPT and ZnPT;the CAT activity was significantly inhibited by CuPT and ZnPT;ZnPT significantly inhibited GR activity,the GR activity was significantly induced or no significant exposure to low concentration CuPT at different time,the GR activity was significantly inhibited exposed to high concentration CuPT at different time.4.At low concentration of CuPT,the GSH content showed no significant change,while the GSH content was inhibited after exposed 12 hour and 24 hour,and the inhibit effect showed more significant with the extension of exposure time,theGSH content increased then decreased when exposed to high concentration CuPT;under the stress of ZnPT,the GSH was significantly induced after exposure 6 hours,then significantly inhibited with the extend of exposure time.5.Lipid peroxidation:at low concentration of CuPT or ZnPT,only the group exposed to ZnPT 24 hours appear significant lipid peroxidation,the other group no significant with control;at high concentration of CuPT or ZnPT,all groups exposed to CuPT and ZnPT showed significantly high levels of lipid peroxidation,it indicated that the cell of Hydroides elegans sufferred different levels of oxidative damage,and the damage levels increased with the extension of exposure time.6.DNA damage:the damage level of Hydroides elegans sperm was increased distinctly with the increase of the exposure concentration of CuPT or ZnPT.The tail length,tail DNA%and Olive tail moment of experimental groups were significantlyhigher compared to both the blank and solvent control groups.