Toxicity Daphnia

Figure 5-31. Search for atrazine and daphnia toxicity in the Cennan Environmeiital Information NetworkGEIN portal (excerpt from search, October 21, 2002) http //wu u. geln.de/incfex en.htm ).

Acute daphnia toxicity Biodegradability Physico-chemical properties cumulative... 

LAS homolog Acute fish toxicity (LC50) [mg/L] Long-time fish toxicity (NOEC) [mg/L] Acute daphnia toxicity (ECS0) (mg/L) Long-time daphnia toxicity (NOEC) (mg/L)... 

Daphnia toxicity (Daphnia magnallA h) (OECD 202) ec50 12.5... 

Ecotoxological Algal growth inhibition 21 day Daphnia toxicity Prolonged toxicity to fish Bioaccumulation in fish Prolonged biodegradation Effect on higher plants Effect on earthworms... 

REDUCED Additional acute toxicity Acute daphnia toxicity Biodegradability Physico-chemical properties 100 kg/annum or 500 kg cumulative... 

Finally, the Aquatic Toxicity module predicts fish and daphnia toxicity providing LC50 values (mg/L) for Pimephales promeals (Fathead minnow) and Daphnia magna (Water flea). Experimental values (if present) and similarity to test compound are shown for the five most similar structures from the training set [65]. 

The evaluation for aquatic toxicity on daphnids and fish is reported in Tables 12 and 13. Bold values indicate that compounds are out of the model applicability domain (ECOSAR) or that the prediction is not reliable. ECOSAR and ToxSuite are able to predict all the selected compounds while T.E.S.T. fails in prediction for the daphnia toxicity of perfluorinated compounds (PFOS and PFOA). Tables 12 and 13 include also a limited number of experimental results provided by the model training dataset (some data are extracted from USEPA Ecotox database). Predicted results are in agreement for five compounds only (2, 3, 5, 13 and 14) for both endpoints while the predictions for the other compounds are highly variable. 

According to the results obtained, and assuming that the simple additive approach applied is valid, malathion appears to be the main contributor to Daphnia toxicity (98% toxic contribution on average for all samples) molinate, fenitrothion, and malathion would be the most relevant pesticides in the case of V. fischeri... 

Acute Daphnia toxicity (if needed for risk assessment)... 

Acute Daphnia toxicity Possible additional studies ... 

Toropov AA, Benfenati E (2006b) QSAR models for Daphnia toxicity of pesticides based on combinations of topological parameters of molecular structures Bioorg. Med. Chem. 14 2779-2788. 

According to wastewater requirements, the water quality of effluents should not be toxic on the basis of results of two acute toxicity tests. The following tests can be applied toxicity to fish, toxicity to daphnia, toxicity to luminescent bacteria, toxicity to green algae [205]. 

C. Porcelli et al., Regulatory perspectives in the use and validation of QSAR. A case study DEMETRA model for daphnia toxicity. Environ. Sci. Technol. 42, 491 196 (2008)... 

Standard acute toxicity tests of Ugilec 141 with bacteria and algae showed no measurable effects. In contrast, Daphnia toxicity was comparable to that of a PCB formulation Clophen A60. The EC100, EC50, and ECO values were 520 pgl-1, 180 pgl-1, and 60 pgl 1 for Ugilec 141, and 420 pg l-1,190 pgl, and 53 pg l-1 for Clophen A60, respectively [100]. 

Ecotoxicological data Acute fish toxicity Prolonged Daphnia toxicity... 

In Figure 3.13A the data of 95% confidence limits are presented curve-fitted to a Daphnia toxicity test. Test concentrations are from very high to very low with no replication. The confidence interval at the EC, and EC20 are relatively low in each instance. In contrast, Figure 3.13B has fewer test concentrations for replicates. The test concentrations do not extend to levels corresponding to EC20. Note that the confidence interval is very narrow within the area of the graph represented by data. However, as extrapolation is required at lower concentrations, the confidence interval expands. 

Why is the use of a reference toxicant important in the daphnia toxicity test ... 

TOXICITY Toxicity threshold (cell multiplication inhibition test) bacteria Pseudomonas putida) 115 mg/L, algae Microcystis aeruginosa) 33 mg/L protozoa Entosiphon sulcatum) 20 mg/L bacteria E. coli) toxic 100 mg/L algae Scenedesmus) toxic 40 mg/L Arthropods Daphnia) toxic 6 mg/L Fish Salmo ja/ar, juvenile) lethal threshold, S 700 pg/L... 

Toxicity to daphniae Toxicity to fish EC50 (48 h) >100 mg 1 acutely not harmful EC50 (48 h) >6.3 mgl acute toxic LC50 (96 h) >100 mg 1 acutely not harmful... 

In Phase II, important processes that affect the chemical composition, toxicity, and fate of leachates from highway C R materials and assemblages were evaluated in laboratory tests [1-4,215,216,222-224]. The tests provided information on the teachability of constituents in C R materials under a range of conditions thought to provide reasonable estimates of expected leachate chemical concentrations. The tests provided information on the removal, reduction, and retardation of leachate constituents by natural processes. Algae and daphnia toxicity tests assessed the toxicity of the samples at the leachate source or after modification by RRR processes, and chemical analyses enabled quantification of leachate chemical components at all stages of the laboratory tests. Each laboratory test resulted in the measurement of mass transfer rates of leachate chemical components under controlled conditions, the results of which were applied to specific mathematical models of the process. 

Surfactant Fish toxicity, LC50 Daphnia toxicity, EC50 Toxicity data for Remarks... 

Effects-related parameters toxicity to fish toxicity to Daphnia toxicity to algae toxicity to mammals mutagenicity. 

Published data on Daphnia toxicity are highly variable because of the diverse test protocols applied and hence are of limited use for the derivation and validation of sound QSAR models. Validated reference data sets are not available (unlike fish) and if data are retrieved from the literature, therefore, care should be taken that they have been conducted according to standard protocols and evaluated by consistent criteria. The important test parameters should be identical or comparable throughout the data set. If, however, they vary, they should be critically evaluated for their effect on the test results, as such differences may greatly affect the relevance of the QSAR models derived. 

Daphnia (coimnonly named water flea) is one of the most common crustaceans to be found in lakes, ponds and streams. The Daphnia toxicity test can establish whether degradation products present in liquid pose at r problem to surface water bodies. In the test, Daphnia are placed in test solutions for 24 hours. After exposure the number of surviving oiganisms is counted and the per cent mortality is calculated. The results are usually expressed as 24h EC 50 (Table 7.5). 

Acute/chronic Daphnia toxicity Synthetic test medium 100/10-<0.1... 

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