The potential of alkyl amines as antifouling biocides .1. Toxicity and structure activity relationships

The in vivo toxicity of long chain primary, secondary and tertiary amines to the algae Amphora coffeaeformis and Dunaliella parva, and to the nauplii larvae of Artemia salina was established. Structure-activity relationships indicated that toxicity of primary, secondary and dimethyl tertiary amines increased with increasing chain length up to a region of maximum activity with Dunaliella and Artemia. However, all of the amines exhibited similar toxicity to Amphora. With all organisms there was an approximate relationship between the number of carbon atoms in the alkyl chain and toxicity, but small differences between each class of amine existed and were especially pronounced at the shorter chain lengths. Tertiary amines with carbon chains of equal lengths were generally less toxic than amines from other classes, toxicity tending to decrease with increasing chain length. Possible reasons for some of the relationships are discussed.