Effects of three pesticides on the earthworm Eisenia fetida (Savigny1826) under laboratory conditions: Assessment of mortality, biomass and growth inhibition

Abstract

To assess the toxic effects of three pesticides on non-target organism, we exposed the earthworm Eisenia fetida (Savigny 1826) to artificial soil supplemented with different concentrations of the examined pesticides based on the recommended agricultural doses (RAD). Their commercial formulations are: Galition G-5 (insecticide: active ingredient, a.i., malathion and fenitrothion), Terbis (herbicide: a.i. terbuthylazine), and Gardene (limacide: a.i. metaldehyde). The laboratory test was conducted according to the OECD guidelines. Mortality, biomass, and growth inhibition were chosen as toxic endpoints. No death was recorded at the lowest concentration (1/4 RAD) of the insecticide or the limacide after 7- and 14-day exposures, nor was it recorded at the highest concentration (4× RAD) of the insecticide or the limacide after 7-day exposure. Triazine herbicide Terbis was found the most toxic and ecologically dangerous to E.fetida, because it LC50 value (1.26mgkg-1) was very close to the respective RAD and the growth inhibition in all concentrations was significantly positive. Although E.fetida was found susceptible to the organophosphorus insecticide Galition, due to the significant positive growth inhibition at the highest concentration, the value of LC50 was higher than its RAD. On the other hand, metaldehyde limacide Gardena was found ecologically safe because the LC50 value was higher than its RAD and weight was not significantly changed. © 2014 Elsevier Masson SAS.