The assessmant of marine polution - bioassays with bivalve embryos and larvae

• Main Authors: His, E., Beiras, R., Seaman, Matthias
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 1999
• Subjects: Crassostrea gigas
• Online Access: https://oceanrep.geomar.de/id/eprint/6636/; https://oceanrep.geomar.de/id/eprint/6636/1/His%20et.al.pdf; https://doi.org/10.1016/S0065-2881(08)60428-9

Tens of thousands of synthetic substances are in existence today and hundreds of new compounds are being introduced every year. Because of the complexity of the physico-chemical interactions between pollutants and the marine environment, the potential toxicity of contaminants can be assessed adequately only by means of bioassays with living organisms. From a practical point of view, a bioassay needs to be sensitive and scientifically valid, yield rapid results at moderate cost, and the organism in question must be readily available. Ecotoxicological bioassays with bivalve embryos and larvae fulfil these criteria better than most other tests. They have increasingly come into use during the past three decades and are now commonly employed to ascertain the biological effects of pure chemicals, as well as to determine the quality of effluents, coastal waters and sediments sampled in the field. There do not appear to be very great differences between bivalve species with regard to larval sensitivity to toxicants. The principal species for bioassays are oysters (Crassostrea gigas and C. virginica), and mussels (Mytilus edulis and M. galloprovincialis). Bioassays are conducted with gametes and larvae of ail ages: sperm and unfertilized eggs, embryos, young D-larvae, intermediate umboned larvae, and pediveligers towards the end ofthe pelagic period. Embryos are usually the most sensitive stage. Recent advances now also permit bioassays on metamorphosing pediveligers, a method particularly suited to investigate the effects of adsorbate-contaminated surfaces. There are various criteria for the assessment oftoxic effects, including embryogenesis success (abnormalities), larval growth, mortality, physiology (e.g. feeding or swimming activity), and metamorphosis success. Chronic toxicity studies may be carried out over periods ofseveral weeks, but larval rearing in the laboratory requires considerable effort (e.g. cultivation of algal food). The method of choice for investigations of acute toxicity and for routine monitoring ...