Bioremediation of chlorpyrifos residues using some indigenous species of bacteria and fungi in wastewater.

Pollutants cause a huge problem for humans, animals, plants, and various ecosystems, especially water resources. Agricultural, domestic, and industrial waste effluents change the water quality and affect living microorganisms. Therefore, the current study aimed to identify possible microorganisms in wastewater as potential bioremediation agents of pesticide residues. Wastewater samples were collected from El-Khairy agricultural drainage, which receives agricultural and domestic wastes. Bacteria and fungi species were isolated as clean cultures. Wastewater samples were analyzed for pesticide residues via gas chromatography-mass spectroscopy (GC-MS) system. Results uncovered the presence of ten pesticides ranging from 0.0817 to 28.162 µg/l, and the predominant pesticide was chlorpyrifos. Along with that, about nine species (3 bacterial and 6 fungal) were relatively efficient in the removal of chlorpyrifos residues up to 2000 µg/l with removal percentages ranging from 24.16 to 80.93% under laboratory conditions. Two bacterial isolates proficiently degraded significant amounts of chlorpyrifos: Bacillus cereus strain PC2 (GenBank accession No. MZ314010) and Streptomyces praecox strain SP1 (GenBank accession No. MZ314009). In-site bacterial and fungal isolates defined in the current study were proficient in cleaning wastewater of chlorpyrifos pesticide residues.

Use of DNA adduct and histopathological defects as indications for bio-persistence potency of zinc oxide nanoparticles in gastropod, Monacha cartusiana (Mǜller) after short-term exposure.

The cytotoxic effects of metallic nanoparticles (MNPs) might be revealed in genomic and histopathological defects. Therefore current study aimed to assess the bio-persistence and adverse effects potency of zinc oxide nanoparticles (ZnONPs) in the gastropod, Monacha cartusiana. Gastropods were exposed to 74 µg/mL for 14 d then the DNA adduct and histopathological defect profiles were assessed. The results demonstrated significant decline in the estimated genomic template stability (GTS%) in haemolymph and digestive gland ranging from 10.0 to 42.9% in treated animals compared to controls. In the treated and recovered snails, randomly amplified polymorphic (RAPD)-DNA showed the appearance and/or disappearance of DNA bands, indicating DNA damage due to the cytotoxicity of ZnONPs on gastropods. Significant defects in microvilli (MV), nucleus (N), mitochondria (M), and execratory glands (EXG) were noticed in the treated individuals with respect to controls. The remaining live animals were subjected to a recovery period (14 d, without treatment) and slight recovery profiles were reported for both measures compared to the control group. The recovery pattern was recognized in the nucleus/cytoplasm ratio with 0.186 and 0.428 in the treated and recovered groups concerning their control (0.176). The studied parameters reported herein might be reliable tools to assess accumulation and bio-persistence patterns of NPs in the organisms for short-term exposure indicating the cytotoxic and genotoxic effects. Also, gastropods may provide simple models for evaluating the ecotoxicological effects of nanomaterials.