Marine toxicity tests development with a New Zealand echinoid
- NIWA, Hamilton (New Zealand)
The generally low levels of contamination around New Zealand lead to the search for a sensitive toxicity test, which could be used to screen effluent and to detect contaminant effects in coastal waters and sediments. Echinoid early life stage tests were considered ideal candidates. However, the adaptation of international toxicity test methods to indigenous species has not been straightforward or troublefree! The echinoid Fellaster zelandiae was selected because it is abundant around New Zealand and is fertile year round. Fertilization tests showed that gamete density, rather than sperm/egg ratio, was a crucial factor for successful control fertilization rates. This method, however, presented several problems related to (1) temporal variability in the quality of sperm batches, (2) rapid reduction of egg quality and viability after spawning, and (3) highly variable sensitivity in reference toxicant tests. Embryo tests were more reliable, with good control results (> 80% normal embryos) and consistent sensitivity to a reference toxicant, zinc sulfate. EC{sub 50} values averaged 0.06 mg Zn/L, comparable to the sensitivity of echinoid species used elsewhere. Brine prepared by freezing seawater was suitable for adjusting the salinity of effluents, with more than 90% normal embryos developing in brine diluted with UV-treated deionized water as a test-control. The assessment of the embryo development test as a tool for screening sediment toxicity (using sediment pore water), is presently underway, concurrently with growth and behavioral endpoint tests using indigenous amphipods and bivalves.
- OSTI ID:
- 392301
- Report Number(s):
- CONF-9511137--; ISBN 1-880611-03-1
- Country of Publication:
- United States
- Language:
- English
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