Genotoxicity and oxidative damage in zebrafish (Danio rerio) after exposure to effluent from ethyl alcohol industry.

In this research, the toxicological effect of untreated wastewater from of ethyl alcohol industry was evaluated on the zebrafish (Danio rerio) under experimental conditions. Fish were treated with zero, half, one and two percent of sewage effluent for 21 days. Toxic effects were monitored in liver by determining biochemical indicators, oxidative stress biomarkers, and the expression of genes involved in the detoxification. Results showed that Sod1, Gstp-1a, Gpx1a gene expressions were significantly increased in the hepatocytes after 21 days at 2.0% sewage exposure. Sewage exposure also significantly increased Gsr, Ces2 and Cyp1a, Mt1 and Mt2 gene expression in the hepatocytes of zebrafish as compared to the reference group (P < 0.01). Total cellular antioxidants, malondialdehyde (MDA) levels, aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and alkaline phosphatase (ALP) activities in fish exposed to 1 and 2% of sewage were significantly higher than the control group (P < 0.01), whereas alanine aminotransferase (ALT) was only increased in fish exposed to 2% sewage (P < 0.01). A significant decrease in gamma-glutamyl-transferase (GGT) activity in fish exposed to 2% effluent was found (P < 0.01). Catalase (CAT) activity was increased in zebrafish exposed to all concentrations of effluent. The transcriptional analysis of the detoxification-related genes and the changes in the biochemical indicators evidenced that drainage of sewage effluents from the ethyl alcohol company is a serious threat to the health of aquatic animals in the Khorram-Rood River. These results will contribute to further study on the impact of sewage effluents of the alcohol industry on aquatic organisms.

Evaluation of single and combined effects of cadmium and micro-plastic particles on biochemical and immunological parameters of common carp (Cyprinus carpio).

The growing accumulation of microplastics (MPs) in aquatic environments is a global concern. MPs are capable to interact with other environmental contaminants, including heavy metals, altering their toxicity. The aim of the study was to investigate the sub-lethal effects of cadmium chloride (Cd) alone and in combination with MPs on common carp (Cyprinus carpio). Multi-biomarkers, including plasma biochemical parameters and intrinsic immunological factors, were measured after 30 days of exposure. Exposure to Cd or NPs reduced the plasma activities of acetylcholinesterase (AChE) and gamma-glutamyl-transferase (GGT) and increased aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and alkaline phosphatase (ALP). Exposure to both compounds enhanced the observed effects except for AST activity and ALP at the highest concentrations, whereas evidenced an antagonistic interaction in ALT. Plasma total protein, albumin, and globulin levels were decreased, and the levels of glucose, triglyceride, and cholesterol levels increased mainly in the Cd groups with no additional effects derived from the co-exposure to both stressors. Lysozyme and alternative complement (ACH50) activities and the levels of total immunoglobulins, and complement C3 and C4 in fish exposed to Cd and MPs were lower than those in the control group and this decrease was more significant by the mixture of both compounds. These findings showed that the exposure to Cd or MPs alone is toxic to fish altering the biochemical and immunological parameters. Moreover, these alterations are even greater when the Cd and the MPS are combined suggesting synergistic effects in increasing Cd toxicity and vice versa.