SCREENING OF CHEMICAL TOXICITY TO MARINE BORERS.

A former report (TR-048) describes the methods employed in testing the toxicity of chemicals toward adult Limnoria tripunctata and the larvae of Teredo diegensis and presents some toxicity data. This report presents all toxicity data gathered as a part of the toxicity screening program and analyzes this data with respect to chemical structure and toxicity mechanisms. These correlations are of necessity sometimes vague because of the lack of sufficient data on toxicity mechanisms as well as the multiple mechanisms by which some chemical compounds can act. The most striking and significant finding was the discovery that chemical compounds that were toxic to one borer genus frequently or even generally were little toxic or nontoxic to another genus. When a chemical compound exhibited toxicity to both genera of test animals employed in this test, the toxic mechanism was generally different in each case. An improved marine wood preservative, therefore, must contain a combination of agents that act by different toxic mechanisms rather than a single chemical compound or group of compounds that act by a single toxic mechanism or predominately by one mechanism. The results of the toxicity screening tests have been employed by the Laboratory as a guide in the selection of the compounds for its Harbor Screening Test Program. (Author)