ACUTE AND SUB-ACUTE TOXICITY OF CHLOROFORM AND IODOFORM (DISINFECTION BY- PRODUCTS) ON COMMON CARP (CYPRINUS CARPIO)

Abstract

Disinfection is intended to improve drinking water quality and human health. Though, disinfectants may transform organic matter and form disinfection by-products (DBPs), many of them branded as cyto and genotoxic in nature. Traditionally, research focuses on the effects of DBPs to human health, but cytogenic and genotoxic impacts on aquatic organisms still remained ill defined. Which is why, current study examines the potential toxic effect of chloroform and iodoform (DBPs) on common carp (Cyprinus carpio), selected as a model organism. Healthy fish specimens were exposed to various concentrations of chloroform and iodoform primarily based on LD50 values, where acute toxicity was monitored for 96 h. The LD50 was determined to be 3 and 90 mg/L for iodoform and chloroform respectively. Headspace SPME analysis through gas chromatography was conducted to assess either applied doses (75.5 – 87.5 and 2.1 -2.9 mg/L for chloroform and iodoform respectively) effects fish blood samples or not. Genotoxicity was monitored using Comet assay. Tail length, tail DNA and olive tail moment values were quantified to be significant (P<0.05) as compared to control. Results shows that the mean tail length values for iodoform (11, 17,25,33,41 μm) was significantly higher than chloroform (6, 12, 15, 18.3,22 μm) at all observed concentrations. Cytotoxicity through hematology and biochemistry showed a dose-response relationship. Statistically significant (p<0.05) decrease in all blood parameters {(white blood cells (WBC), red blood cells (RBC), platelets (PLT), hematocrit (Hct), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC) and hemoglobin (Hgb)} was observed with increase dose concentration and exposure time. The change was more significant in case of iodoform at all administered doses in comparison to chloroform analogue. The changes in biochemical indices (glucose, total protein and alanine aminotransferase) were also statistically significant (p<0.05). But, ALT secretion was significantly increased (93±0.05 and 82.8 ±0.1U/L) at higher concentration compared to control (56±0.1U/L), suggesting liver damage. Thus, results demonstrated that iodoform was statistically more damaging as compared to chloroform. Keywords: Biochemical count, chloroform, comet assay, cytotoxicity, disinfectant by-products, genotoxicity, hematology, iodoform.