S E Belanger | PubMed Health

PubMed1986

Effects of chrysotile asbestos on coho salmon and green sunfish: evidence of behavioral and pathological stress.

The effects of chrysotile asbestos on larval coho salmon (Oncorhynchus kisutch) and juvenile green sunfish (Lepomis cyanellus) were investigated at levels approximating those reported in the Great Lakes basin (10(6) fibers/liter). Behavioral stress effects, such as loss of rheotaxic position and balance, were observed in salmon exposed at 3.0 X 10(6) fibers/liter and in sunfish exposed at 1.5 and 3.0 X 10(6) fibers/liter. Coho larvae at 1.5 X 10(6) fibers/liter were significantly more susceptible to an anesthetic stress test, becoming ataxic and losing equilibrium faster than control cohorts (P less than 0.001). Two of 106 larvae exposed at 3.0 X 10(6) fibers/liter developed tumorous swellings and three additional fish developed coelomic distentions. Cytological examination of ventral epidermal tissue revealed cellular histolysis, and evidence by transmission electron microscopy confirmed the presence of asbestos in the salmon larvae. Distortion of the lateral line region in asbestos-treated coho salmon was linked to behavioral and orientational aberrations. Differential mortality was not observed between control and treated groups of either test species.

Animals↗

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Ecotoxicological testing: small is reliable.

The focus of environmental regulations has changed significantly since the introduction of the bioassay as a standard means of assessing environmental impact. Prominent in this change is an increasing emphasis on protecting the integrity of natural ecosystems, which incorporate community- and system-level properties as well as organismal and population processes. Consequently, support for the use of multispecies testing has widened to include not only ecologists in academia but environmental scientists in the regulatory and industrial sector as well. The reason for this trend is clear: the additional environmental realism gained from tests utilizing communities of organisms allows for greater insight into the potential hazard of chemicals and other forms of human activity to natural ecosystems that cannot be obtained from single species tests alone. Many of the problems cited for multispecies testing early in their evolution as a hazard assessment tool have been refuted or overcome. In particular, the use of natural microbial communities minimizes several shortcomings typically associated with multispecies toxicity testing. This article includes the utility of microcosm and mesocosm tests using aquatic microbial communities as hazard assessment tools in conjunction with accumulating information on their performance in toxicity testing protocols. An increasing body of experimental evidence supports an expansion in the use of these tests for a variety of regulatory and research purposes. A shift in research focus is needed, however, to answer remaining questions and further refine standard protocols for these valuable ecotoxicological tools.

Biological Assay↗