Papers by Keyword: Heptachlor Epoxide

Abstract: There are many studies that detail how hazardous pesticides are to aquatic life, plants, animals, and humans, but there are fewer that describe how pesticides are treated during a separate treatment procedure. This study, which examines the removal of the highly toxic pesticide "heptachlor epoxide", is crucial to achieving SDG 6. Under operational circumstances, the prepared green nanoiron was successfully synthesized and characterized for the removal of heptachlor epoxide from aqueous solutions. For starting heptachlor epoxide concentrations of 100 and 10 μg/L at neutral medium pH 7, 0.8 g/L of green nZVI for 80 min, and a 200 RPM stirring rate, the removal efficiency varied between 55 and 100%, respectively. The RSM results indicated that the model R² was 94.6%, and all operating conditions were significant to describe the removal efficiency with a p-value <0.05. The linear regression histogram indicated that the variation between expected and experimental removal efficiency ranged between (-1, 1%). The ANNs results by using MLP with network 6-3-1 indicated that nZVI was able to reduce heptachlor epoxide concentrations with a Sum of Squares Error of 0.052 for training and 0.177 for testing. Also, the ANNs described the importance of operating conditions and indicated that the most effective operating conditions were dose and less important was stirring rate, showing agreement with the obtained RSM results. Finally, this paper recommended using nZVI for heptachlor epoxide removal. Keywords Environmental toxicology; climate action; SDG 6; nanotechnology; pesticide removal; Heptachlor epoxide.

Abstract: Although heptachlor epoxide (HE) is the major metabolite of organochlorine pesticide heptachlor in soil, there is very limited information on the biodegradation of HE by microorganisms, and no systematic study on the metabolic products and pathways for HE transformation by fungi has been conducted. In this study, the metabolism of HE was performed with Cordyceps brongniartii ATCC66779, which is capable of degrading polychlorinated dibenzo-p-dioxin. This fungus removed about 27% and 21% of HE in PDB and BSM medium, respectively, after 20 days of incubation. Three hydroxylated products including heptachlor diol, 1,2-dihydroxydihydrochlordene and trihydroxychlordene were detected as metabolites of HE using GC/MS analysis, suggesting that HE was metabolized to hydrophilic products via hydrolysis, dechlorination and hydroxylation.

Abstract: Although heptachlor epoxide is one of the most persistent organic pollutants (POPs) that cause serious environmental problems, there is very limited information of the biodegradation of heptachlor epoxide by microorganisms, and no systematic study on the metabolic products and pathway of endrin by microorganisms has been conducted. Wood-decay fungi can degrade a wide spectrum of recalcitrant organopollutants, including polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated biphenyls (PCBs). In this study, 18 wood-decay fungi strains of genus Phlebia were investigated for their ability to degrade heptachlor epoxide, and Phlebia acanthocystis, Phlebia brevispora, Phlebia lindtneri and Phlebia aurea removed about 16, 16, 22 and 25% of heptachlor epoxide, respectively, after 14 days of incubation. Heptachlor diol and 1-hydroxy-2,3-epoxychlordene were detected in these fungal cultures as metabolites by gas chromatography and mass spectrometry (GC/MS), suggesting that the hydrolysis reaction in the epoxide ring and substitution of chlorine atom with hydroxyl group in C1 position occur in bioconversion of heptachlor epoxide by selected wood-decay fungi, respectively. This is the first report describing the metabolites of heptachlor epoxide by microorganisms.