ROMANO, J.; MCCLELLAN-GREEN, P.; RITTSCHOF, D.; Duke University Marine Laboratory; North Carolina State University; Duke University Marine Laboratory: Copper Pyrithione and Diuron Toxicity in the Non-Target Species, Lytechinus variegatus

A large portion of residents living near the US coastline participate in recreational or commercial boating. Fouling organisms such as algae, mussels, sea squirts, and barnacles have historically been a problem and continue to cost the boating industry tens of millions of dollars each year. To control the growth of these organisms on boats, antifouling coatings are periodically applied to their surfaces. Unfortunately, these antifouling coatings leach into the aquatic environment where they have been shown to be extremely toxic toward non-target organisms. Recently, a number of compounds have been added as �boosters� to existing coatings in order to increase their efficiency and reduce their environmental impact on coastal ecosystems. We have examined two of these boosters, copper pyrithione (CPT) and diuron, a commercial herbicide. Adult short spined sea urchins, Lytechinus variegatus were exposed to CPT at 0, 1, 10, 50, and 100 �g/L or diuron at 0.2, 2, 20, and 200 mg/L. The LC50 and the EC50 (losing 5 or more spine per jar) of CPT were found to be approximately 1.5 �g/L and 1.1 �g/L respectively. The LC50 and EC50 of diuron were found to be 10.9 mg/L and 0.25 �g/L, respectively. When fertilized embryos from healthy adults were exposed to CPT or diuron, developmental delays and embryonic death occurred at concentrations of 1 �g/L and 20�g/L, respectively. Further study into the effects of ultraviolet light and leach-rates on environmental toxicity of these compounds must be examined to give a clearer and more defined understanding of their potential application as �booster� biocides. The information obtained thus far on these two compounds indicates that they may be very toxic to the non-target species.