Research Product

The impact of pesticides on the marine environment can be assessed by monitoring their occurrence in the marine environment and by evaluating their toxic effects in laboratory bioassays. Acute static and flow-through bioassays generally have been used to set marine water quality criteria, but bioassay techniques now can determine effects of long-term exposure to one or more toxicants on survival, growth, and reproduction of individual species of mollusks, arthropods and fishes and effects on communities of estuarine organisms in the laboratory. Bioassays have been lengthened from 96 hours or less to between one month and two years, and their complexity has also been broadened. Effects of toxicants on the entire life cycle of an oviparous estuarine fish, Cyprinodon variegatus, can now be studied, and bioassays have been completed with endrin and heptachlor. Preliminary experiments using this fish revealed that they typically develop from an embryo to maturity in 10 to 14 weeks, with about 70% survival in the laboratory. Females produce an average of eight eggs per day and fertilization success exceeds 90%. Effects of a polychlorinated biphenyl, AroclorŪ 1254, and of a pesticide, toxaphene, on developing communities of estuarine animals have been investigated. These studies provided data for predicting pollution-induced shifts in composition of estuarine animal communities.