Aquatic invertebrate tests

The OECD Daphnia spp acute immobilisation and reproduction tests. A mainstay in aquatic toxicity testing, Daphnia tests have been used also to evaluate the toxicity of contaminated groundwaters and leachates (Kross and Cherryholmes, 1992). As with any of the aquatic tests, the principal problem with the Daphnia test is the need to extract a suitable aqueous sample. This problem is illustrated by Kross and Cherryholmes (1992), who compared D. magna and Microtox assay results in leachates but found a poor correlation between the two methods. 

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AH of the propylene glycols are considered to be practically nontoxic to fish on an acute basis (LC q < 100 mg/L) and practically nontoxic to aquatic invertebrates, also on an acute basis. Acute marine toxicology testing (38) on propylene glycol showed that the 96-h LC q for fathead minnows was 54,900 mg/L and the 48-h LC q for Daphnia magna was 34,400 mg/L. A 24-h NOEL of 50,000 mg/L was also observed for fingerling trout. Similar results were observed for guppies and rainbow trout (39). 

Tributyltins and other organotins induce chromosomal aberrations in mammals, although this was not observed in tests with aquatic invertebrates (Dixon and Prosser 1986). Studies with isolated rat hepatoma cells, TBT, and PCB 126, show that TBT inhibits cytochrome P-4501A activity, and PCB 126 induces EROD activity. However, PCB-induced EROD activity was potentiated by coexposure to low noncytotoxic concentrations of TBT (Kannan et al. 1998b). Authors concluded that TBT does not interfere with Ah receptor binding and that potentiation of EROD activity and cytotoxicity as a result of coexposure to PCB 126 and TBT is significant because they coaccumulated in a variety of marine organisms. 

Johnson, W.W. and M.T. Finley. 1980. Handbook of Acute Toxicity of Chemicals to Fish and Aquatic Invertebrates. Summaries of Toxicity Tests Conducted at Columbia National Fisheries Research Laboratory, 1965-78. U.S. Fish Wildl. Serv. Resour. Publ. 137. 98 pp. 

Freshwater and marine alga were unaffected at water diazinon concentrations that were fatal (i.e., 1000 pg/L) to aquatic invertebrates (Stadnyk and Campbell 1971 Shacklock and Croft 1981). However, diazinon at 1.0 pg/L induced extensive clumping of a freshwater alga (Chlorella pyrenoi-dosa) onto the antennae of Daphnia magna within 24 h (Stratton and Corke 1981). The affected daphnids were immobilized and settled to the bottom of the test containers. The causes of particulate matter adhesion are open to speculation, and additional research is merited. 

Anderson, B.G. Aquatic invertebrates in tolerance investigations from Aristotle to Naumann. In Aquatic Invertebrate Bioassays Buikema, A.L. Jr., Caims, J. Jr., Eds. American Society for Testing and Materials Philadelphia, PA, 1980 Vol. 3, 3-35. 

Figure 6.3. The LDj is the concentration of a substance that kills 50% of a test population of organisms. It is a useful measure to compare the toxicity of different substances but it is a very controversial measurement when applied to mammals because of the suffering caused to the animals used to gain the data. Note that if the LDj dose is increased by a factor of 10, nearly 100% of the population will die and if the concentration of the substance drops to one-tenth of the LDg then only a very small percentage will die. The notorious insecticide DDT has an LDj of 150-300 mg kg for rats, 1 g kg for goats, 2 g kg for ducks but <0.1 mg kg for some aquatic invertebrates.

For nanomaterials this is especially true if the exposure scenarios used in the test system are not representative of those likely to be found in the field [91, 92]. For example, the degree of toxicity observed in aquatic invertebrates exposed to multi-walled nanotubes (MWNTs) in water and sediment was influenced by the functional groups on the MWNTs and their preparation for dispersal into the test systems [93]. As noted, even the concept of what constitutes nanomaterials is not fixed [87], so these emerging materials will likely require a rethinking of how their toxicity is assessed and the hazards and risks they might pose to ecosystems [90]. For more information on nanomaterials, including application of life-cycle concepts to their design, see Chapter 8. 

Persoone, G., Van de Vel, A., Van Steertegem, M. and De Nayer, B. (1989) Predictive value of laboratory tests with aquatic invertebrates influence of experimental conditions, Aquatic Toxicology 14 (2), 149-167. 

Aquatic invertebrate acute toxicity, test, freshwater daphnids... 

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