MICROBIAL DEGRADATION OF SULFAMETHOXAZOLE AND EVALUATION OF BIOTOXICITY POTENTIAL IN FISH

Abstract

Ongoing industrial development, urbanization and agricultural trends have given rise to a series of environmental problems amongst which degradation of water bodies is an area of great concern. Various types of pharmaceuticals are detected which probably enter the water bodies through runoff water from poultry sheds, sewage and aquaculture use of antibiotics. Sulfamethoxazole (SMX) is amongst those antibiotics which are extensively used as human and veterinary medicine. This study aims to isolate and identify potential environmental bacteria to degrade SMX and to assess the effects of the antibiotic towards non target organisms such as fish. Dominant strains of bacteria were isolated from five tributaries (Ratahutar, Nupur, Jinnah, Shahdara stream and Korang River) that converge to form Rawal Lake. Water Samples were collected from upstream and downstream points. All samples values were under the permissible limits for TDS and turbidity. Degradation analysis revealed potential strains Pseudomonas aeruginosa was able to degrade SMX and indicated more than 90% removal in MSM and nutrient broth. Later the strain was used to evaluate degradation potential in the presence of fish along with SMX to evaluate toxicity. The results indicated removal 88.52 % of SMX from water. Fish exposed to SMX presented different effect on behavior and body length, weight, hematology and biochemistry which indicated behavioral effects of SMX on fish. During exposure, blood values such as Red blood cell count, Hemoglobin, Hematocrit were found to decrease, where as White blood cell count was found to increase 26.05 10-6/μL. Likewise, other blood parameters such as mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration also indicate decreasing trend, when fish is exposed to SMX. A significant decline was also noted in glucose and protein levels with time (p<0.05). The result from the above study suggests that bacterial strains isolated form stream samples may be used to biodegrade SMX. Bacterial strains used to degrade SMX have no significant effect on fish and may thus have potential for bioremediation for sulfonamide polluted water, whereas SMX has significant effect on fish population and affects them adversely. The alterations of these parameters led to the conclusion that these parameters may be used as biomarkers in monitoring SMX toxicity in aquatic organisms.