Penicillium sp. as an organism that degrades endosulfan and reduces its genotoxic effects.

Endosulfan is an organochloride and persistent pesticide that has caused concern because of its impact in the environment and its toxicity to and bioaccumulation in living organisms. In this study, we isolated an endosulfan-degrading fungus from the activated sludge from an industrial wastewater treatment plant. Through repetitive enrichment and successive subculture in media containing endosulfan as the sole carbon source, a fungus designated CHE 23 was isolated. Based on a phylogenetic analysis, strain CHE 23 was assigned to the genus Penicillium sp. In a mineral salt medium with 50 mg/l endosulfan as the sole source carbon, CHE 23 removed the added endosulfan in a period of six days. To verify the decrease in endosulfan toxicity due to the activity of the fungus, we performed genotoxicity tests trough the single cell gel electrophoresis assay or comet assay, with Eisenia fetida as the bioindicator species. This organism was exposed to the supernatants of the culture of the fungus and endosulfan. Our results indicated that the genotoxicity of endosulfan was completely reduced due the activity of this fungus. These results suggest that the Penicillium sp. CHE 23 strain can be used to degrade endosulfan residues and/or for water and soil bioremediation processes without causing toxicity problems, which are probably due to the generation of no-toxic metabolites during biodegradation.

Toxicity assessment of a complex industrial wastewater using aquatic and terrestrial bioassays Daphnia pulex and Lactuca sativa.

Aquatic and terrestrial bioassays were used to assess toxicity at several stages in an industrial wastewater treatment plant that processes 400 L/s from a complex influent formed by wastewater from 135 industries. Daphnia pulex and Lactuca sativa were used to assess and compare toxicity between the influent wastewater and effluent wastewater from an activated sludge process, and compare their relationship with physicochemical parameters of Biological Oxygen Demand (BOD); Chemical Oxygen Demand (COD); Total Suspended Solids (TSS); total Nitrogen (N (N-total)), and ammonia Nitrogen (N (N - NH3)). Samples from the primary clarifiers (PC), mix liquor stage (ML) and secondary clarifiers (SC) were processed using physicochemical and bioassay test. Toxicity results with Daphnia pulex showed decreased mean values of acute Toxic Units (a.T.U.) between PC (2.1 a.T.U.) and SC (1,25 a.T.U.). Lactuca sativa showed high values of toxicity between PC and SC (3.37 and 3.32 a.T.U. respectively). Some samples exhibited higher toxicity values at the effluent stage (SC) than the influent stage (PC). The highest correlations of physicochemical properties with toxicity were obtained with COD and nitrogen compounds in effluent samples (SC), but not with influent samples (PC).