Table 5: Additional methiocarb toxicity data for aquatic invertebrates Species Study type New value Value used in DotE Comments/Recommendation Reference 2006 assessment Daphnia Acute, 48 h EC50 = EC50 = 0.019 mg/L On its own, the new data Peither, A. magna 0.0077 require a significant change 2000 mg/L in the aquatic invertebrate end point from the previous risk assessment. This new study reports a result that was previously known, but did not have the study to assess it. Consequently, the assessment needed to apply a higher value. The Daphnia magna acute endpoint was the lowest aquatic value used in the risk assessment so adoption of this new value will result in increased risk if the same exposure arguments from the previous assessment are applied. Daphnia Chronic 21 d, NOEC > 3 NOEC = 0.0001 This value may be used to Dorgerloh, M. magna water/sed X 0.008 mg/L refine the risk assessment 2007 mg/L but a full analysis of the study would be required. It indicates a more realistic exposure situation through the inclusion of sediment in the test system helps reduce toxicity. The preliminary environmental assessment does not address chronic risk. EC50 = Effective concentration 50%. NOEC = No Observable Effect Level. Table 6: Additional methiocarb toxicity data for algae Species Study New value Value used in DotE Comments/Recommendation Reference type 2006 assessment Scenedesmus Chronic, EC50 = 96 h EC50 = The preferred assessment Peither, subspicatus 72 h 2.2 mg/L 1.15 mg/L is growth rate, but with A. 2000 (growth rate) limited data, the biomass value can be applied for increased conservatism. This study on its
Table 5: Additional methiocarb toxicity data for aquatic invertebrates Species Study type New value Value used in DotE 2006 assessment Comments/Recommendation Reference Daphnia magna Acute, 48 h EC50 = 0.0077 mg/L EC50 = 0.019 mg/L On its own, the new data require a significant change in the aquatic invertebrate end point from the previous risk assessment. This new study reports a result that was previously known, but did not have the study to assess it. Consequently, the assessment needed to apply a higher value. The Daphnia magna acute endpoint was the lowest aquatic value used in the risk assessment so adoption of this new value will result in increased risk if the same exposure arguments from the previous assessment are applied. Peither, A. 2000 Daphnia magna Chronic 21 d, water/sed NOEC > 3 X 0.008 mg/L NOEC = 0.0001 mg/L This value may be used to refine the risk assessment but a full analysis of the study would be required. It indicates a more realistic exposure situation through the inclusion of sediment in the test system helps reduce toxicity. The preliminary environmental assessment does not address chronic risk. Dorgerloh, M. 2007 EC50 = Effective concentration 50%. NOEC = No Observable Effect Level. Table 6: Additional methiocarb toxicity data for algae Species Study type New value Value used in DotE 2006 assessment Comments/Recommendation Reference Scenedesmus subspicatus Chronic, 72 h EC50 = 2.2 mg/L (growth rate) 96 h EC50 = 1.15 mg/L The preferred assessment is growth rate, but with limited data, the biomass value can be applied for increased conservatism. This study on its Peither, A. 2000
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