Biological effects of pollutants in Australian tropical coastal waters: Embryonic malformations and chromosomal aberrations in developing fish eggs

This study establishes baseline information on the biological effects of contaminants in the tropical marine environment of Australia, using as indicators the incidence of embryonic malformation and chromosomal aberration in developing fish eggs. Eighteen sites were examined, including nearshore coastal waters with varying degrees of human activity, and offshore locations on the Great Barrier Reef, in order to assess whether there is any present indication of contaminant effects in the region. Natural background levels of abnormality in embryos and chromosomes of fish are both expected to be less than 10%. All sites examined had chromosomal aberrations well within this limit, and as such, could be classified as uncontaminated by toxicants which have mutagenic effects. Mean rates of embryonic malformation varied with site location, and ranged between 6 and 24%. Coastal sites adjacent to areas used for intensive farming, or with major urban centres, had consistently higher levels of embryo deformity than sites on the Great Barrier Reef. Thus, whilst the incidence of embryonic malformation for the region as a whole (mean 12%) was low in comparison with that of polluted waters (30–80% reported), there is some concern that human activities may be having a localized effect in the region.