Applied Microbiology

Environmental toxicology, also known as entox, is a multidisciplinary field of science concerned with the study of the harmful effects of various chemical, biological and physical agents on living organisms. Ecotoxicology is a subdiscipline of environmental toxicology concerned with studying the harmful effects of toxicants at the population and ecosystem levels.

Significance of Environmental Toxicology: Effects on non-target terrestrial species Manufacturers are required to provide environmental toxicology data on the effects of their pesticides on birds, invertebrates and plants. Among birds, the bobwhite quail and mallard duck are typical test species. Acute and chronic oral and dietary toxicity tests and reproduction tests are conducted with each of the two species. The reproduction test is designed to check for the mortality of adults and chicks (both hatched and unhatched), as well as such sublethal effects as reduced egg production and thin eggshells. Effects on wild mammals are predicted from the mammalian toxicology risk assessment. This assessment entails a review of acute oral, dermal and inhalation toxicity, short-term toxicity, long-term toxicity, genotoxicity, reproductive toxicity and teratogenicity studies.

Laboratory studies are also conducted to determine toxicity to:

• Earthworms, which are important for soil fertility.
• Invertebrates, such as bees and other insect pollinators.
• Predatory or parasitic insects and predatory mites.
• Non-target terrestrial vascular plants.

Effects on non-target aquatic species Acute- and chronic-toxicity tests are conducted with both cold- and warm-water fish species (rainbow trout and bluegill sunfish, respectively). Data on toxicity to marine fish are reviewed when relevant to the proposed use-pattern. Information on acute and chronic toxicity to aquatic arthropods, such as water fleas (Daphnia species) is reviewed because of the important role these and other invertebrate species play in the aquatic ecosystem. Effects on molluscs (shellfish) are evaluated for pesticide uses that involve deposition in marine environments. Results of toxicity tests on freshwater and marine algae and aquatic vascular plants are also evaluated.