Fish eggs, toxicity testing

OECD Draft Guideline Fish, acute toxicity test on egg and sac-fry stages. OECD Guideline for Testing of Chemicals. Draft, 1992. 

By far the most comprehensive research into AHR-related effects of PCDD/Fs on fish was a retrospective analysis of Lake Ontario lake trout reproductive impairment due to AHR-mediated early life stage mortality [16]. This includes blue sac disease as well as sublethal effects, which may increase susceptibility of sac fry and alevins to increased mortality and predation during swim-up. Lake trout are more susceptible to AHR-mediated toxic effects than any other Great Lakes species, with the possible exception of mink. WHO TEFs for fish were used to calculate the 2378-TCDD equivalent (TECegg or TEQ) concentrations in lake trout eggs. The validity of the additive toxicity equivalence model was established through early life stage trout toxicity tests. The WHO fish TEFs are likely to be fairly robust for lake trout, since they were determined primarily from relative potency values for effects in embryos of a related salmonid, rainbow trout, even if the relative sensitivity of the species to 2378-TeCDD toxicity may be different. 

DEV T6 - DIN 38415-6 (2003) German standard methods for the examination of water, wastewater and sludge - Sub-animal testing — Part 6 Toxicity to fish Determination of the non-acute-poisonous effect of wastewater to fish eggs by dilution limits. Beuth Verlag, Berlin, Germany. 

Similar toxicity tests also were conducted on eggs of several other fish species. Probit-derived LC50 values determined at 4 days posthatching were 0.3,0.7, and... 

The risk assessors conclude that Octa can be considered persistent in the environment but that the available laboratory data indicates a low potential for bioaccumulation. Furthermore, it is concluded that Octa shows no toxicity towards aquatic organisms up to the limit of water solubility, and that effects in other organisms are only observed at relatively high concentrations, based on standard laboratory tests. Nevertheless, the risk assessors note that environmental monitoring of concentrations in biota indicate that Octa, as well as HexaBDE, and HeptaBDE are present at low concentrations in fish, marine mammals and predatory birds eggs. 

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