Vermicomposting Process to Endosulfan Lactone Removal in Solid Substrate Using Eisenia fetida

Abstract

Pesticide by-products found in soil are usually more toxic and persistent than the pesticides themselves. For example, Endosulfan lactone (EL) (a by-product of the organochloride pesticide endosulfan). EL is created by the enzymatic activity (and related oxidative processes) of microorganisms in the soil. A sustainable method of EL removal is the introduction of Eisenia fetida earthworm. In this paper, it will be demonstrated the impact of vermicomposting process related to Eisenia fetida earthworm on EL by measuring initial and final concentrations of the compound and overall enzymatic activity in sterile and non-sterile solid substrate over 56 days. As a baseline, it be observed there were higher EL removals in non-sterile solid substrate (90.86%) at day 5 than in sterile solid substrate (83.86%) at day 14. In samples with Eisenia fetida, the presence of EL in non-sterile solid substrate was 36%, however in sterile solid substrate it was only 18% at day 1 and 7, with a maximum enzyme activity of 0.4659 mmol/mg protein per min at day 7. The evidence found in this study suggests that EL removal in a non-sterile solid substrate is higher when a vermicomposting is present and that the influence of microorganisms from the solid substrate with the earthworm, increases removal.

Toxicity Assessment of a Biolubricant Exposed to Eisenia fetida

“…Vázquez-Villegas et al [16] indicated that growth inhibition suggests that few nutrients in the substrate were sufficient for earthworm survival and were insufficient for their growth and development.…”

“…The earthworms Eisenia fetida (Savigny, 1826) were obtained from the Luanda farm, located in Ocozocoautla de Espinoza, Chiapas, Mexico (latitude 16 The solid substrate used was made up of 85% peat and 15% rabbit manure that was previously dried, ground and sieved to a particle size of 0.2 and 0.5 mm, which was used for the earthworms to adapt to over 60 days at 25 • C and 60% humidity, feeding them every third day. This was carried out in order to achieve a uniform size of the worms and to ensure they had developed clitella [16].…”

“…Therefore, it is important to know the fate and persistence of these compounds in nature. A tolerable limit of these compounds can be calculated through toxicological tests using sensitive organisms [16]. In bioassays, a living tissue, organism or group of organisms is used as a reagent to assess the effects of any physiologically active substance.…”

“…The toxic effects can include mortality, immobility, growth inhibition, behavioral deterioration and weight loss, among others. Variables such as the median lethal concentration (LC50), which is the lethal concentration for 50% of those exposed, are determined [16]. Through histological tests, it is possible to determine the tissue damage that the test organism could experience in order to be able to examine and analyze its morphological components, as well as its structure through the microscope [17,18].…”

“…Through histological tests, it is possible to determine the tissue damage that the test organism could experience in order to be able to examine and analyze its morphological components, as well as its structure through the microscope [17,18]. Eisenia fetida was used as a test organism [16].…”