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Toxicity to terrestrial arthropods

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Description of key information

LD50 values (24h) = 46.9 and > 50 µg per animal (41.7 and 44.5 µg a.i. per animal) (Apis mellifera, oral and contact exposure respectively)
LR50 values (27 and 40 d) > 3 L test substance/ha (2.4 mg a.i./kg dry weight soil)(Chrysoperla carnea and Coccinella sectempunctata)

Key value for chemical safety assessment

Additional information

The acute toxicity of sodium 2,4-dichlorophenoxyacetate (CAS No. 2702-72-9) to honey bees was investigated in one study (Londzin, 1996). This test was performed according to the Hygienic-Toxicological Requirements for Pesticides Registration in Poland and Germany DR, Method No 12 (1976). The test material was administered orally and via dorsal contact, leading to LD50s of 46.9 µg and > 50 µg test substance per animal respectively (41.7 and > 44.5 µg a.i. per animal,

values determined 24 hours after application). Additional studies testing the effects of this substance on honey bees were available. However, the validity criteria for these tests were not fulfilled and therefore, they were disregarded for further assessment.


Long-term toxicity tests on arthropods using sodium 2,4-dichlorophenoxyacetate as test compound were not available. Therefore, two long-term studies conducted with an analogue substance, dimethylammonium 2,4-dichlorophenoxyacetate (CAS No. 2008-39-1 ) were used to draw conclusions about the chronic effects of the reference substance. Dimethylammonium 2,4-dichlorophenoxyacetate was tested in two extended laboratory assays using Chrysoperla carnea and Coccinella sectempunctata as test organisms. Both studies were conducted according to ESCORT Guidance documents I and II (Barret, 1994; Candolfi, 2001), under GLP conditions. No significant effects were observed on survival or reproduction of Chrysoperla carnea or Coccinella sectempunctata after 27 and 40 days of exposure to the test material respectively. Thus, a LR50 value could not be determined and it is assumed to be greater than 3 L test substance/ha (2.4 mg a.i./kg dry weight soil).