ASSESSING POTENTIAL TOXICITY OF SULFAMETHOXAZOLE (SMX) IN FISH USING DIFFERENT BIOMARKERS

Abstract

Pharmaceuticals are considered as emerging contaminants due to their frequent use, detection in different environmental matrices in high concentrations and the potential risk to the ecosystem. Sulfonamides such as Sulfamethoxazole (SMX) have been predominantly used to treat bacteria and other diseases because of their low cost and effectiveness in tackling bacterial infections. SMX are not acutely toxic but has chronic effects on organisms. Fish are highly sensitive to even slight environmental changes; their physiological and biochemical alterations reveal the health status of organism and its surroundings. Fish biomarkers such as biochemical parameters, Respiratory Burst Activity and Oxidative Stress in blood and organs were routinely analyzed once exposed with Sulfamethoxazole to assess health condition of fish in the present study. DNA damage and bioaccumulation of SMX was also measured in grass carp. Acute toxicity of SMX in fish was measured by exposure to different concentrations ranging from 200-1200mg/l. Lethal dose (LD50) was obtained out at 1000 mg/L after 48 hrs. Sub-Lethal toxicity was calculated by exposing fish to different concentrations of SMX ranging from 200-1000mg/L. The findings suggest that existence of a cause-and-effect relationship between exposure to sulfamethoxazole and Enzymatic Activity (Respiratory Burst Activity), change in biochemical parameters, and excess generation of ROS indicate that antibiotic exert oxidative stress and cause toxicity in fish tissues. The changes in biochemical indices (glucose, triglyceride total protein and alanine aminotransferase) were also statistically significant (p<0.05). Geno toxicity was monitored using Comet assay. Tail length, head length and olive tail moment values were quantified to be significant (P<0.05) as compared to control. Statistically significant (p<0.05) increase of SMX in muscle tissues was observed with increase dose concentration and exposure time through HPLC chromatographs. Thus, results demonstrated that SMX was statistically toxic at higher concentrations. Keywords: Sulfamethoxazole, fish Toxicity, Biomarkers, Biochemical Parameters, Respiratory Burst Activity, Oxidative Stress, bioaccumulation