Permethrin toxicity tests

Hansen, D.J., L.R. Goodman, J.C. Moore, and P.K. Higdon. 1983. Effects of the synthetic pyrethroids AC 222, 705, permethrin and fenvalerate on sheepshead minnows in early life stage toxicity tests. Environ. Toxicol. Chem. 2 251-258. 

Within the framework of SPEED 98, Japan Environment Agency conducted PLC and/or FLC with 28 of 67 chemicals listed [3]. The results showed that only 3 chemicals, i.e., 4-nonylphenol, 4-t-octylphenol, and bisphenol A were suggested as EDCs. We also conducted sex reversal assay or PLC test (56-day exposure) to evaluate the effects of some pesticides (malathion, benomyl, cypermethrin, permethrin, esfenvalerate, fenvalerate) listed in SPEED 98. The results showed that these pesticides gave no endocrine-disrupting effects even at one-seventh to one-twentieth of the acute toxicity values (Table III). The effect of benomyl on hatchability is likely to be caused by inhibition of cell division. Based on these findings, it is unlikely that these chemicals listed affected as EDCs. 

Post-conditioning treatment to permethrin has been conducted, before subjecting the bees to the test trials, in order to study the recovery period needed for treated bees to resume normal learning ability [33]. This aimed to examine how chemical treatment can interfere with the memory process, which gives an indication of the way foragers will be able to come back to a crop where they have been exposed to the toxic material while they were collecting food and memorizing the floral cues. 

Figure 5, obtained from Wolansky and Harrill (2008), shows the acute toxicity (LD50) values in rats for the parent pyrethroids and one or more of their eruiched isomers. Stmctural information on the compounds tested and their purity was limited to a few of the more commonly used pyrethroids (i.e., allethrin, resmethrin, bifenthrin permethrin, deltamethrin, cypermethrin). The authors recognized the need to standardize test materials, the pyrethroid isomers used in the tests, and their purity for improving the value of information obtained from toxicological studies. 

---