Bioaccumulation and toxicity of 2-naphthalene sulfonate: an intermediate compound used in textile industry

The aromatic compounds substituted with sulfonate groups, being xenobiotic, resist biodegradation in the environment and tend to accumulate up to toxic levels. The hydrophilic sulfonated group makes these compounds highly water soluble and they tend to pass through water-treatment plants. The release of untreated effluents from these industries results in pollution of water bodies affecting aquatic fauna. Thus, the toxicity regarding these compounds is of major concern. The 2-naphthalene sulfonate is a sulfonated aromatic compound being widely used in textile industries. Being non-biodegradable concern regarding its toxicity has risen. Thus in the light of above facts, the present study was undertaken to determine the toxicity of 2-naphthalene sulfonate in blood cells of Channa punctatus. For this, LD50 was determined and after selection of sublethal doses oxidative stress, genotoxicity and bioaccumulation were studied. For oxidative stress determination, biochemical markers such as malondialdehyde content and activities of superoxide dismutase, catalase, and glutathione-S-transferase were studied. Genotoxicity was studied using comet and micronucleus assay. Significant increase in oxidative stress and DNA damage in the exposed groups as compared to control group (P ≤ 0.05) was observed till 96 h. However, decreased values of all the studied parameters at 720 h (30 days) indicate repair capacity of fish. Further, the bio accumulative potential of 2-naphthalene sulfonate was assessed in blood plasma using high-performance liquid chromatography. The study revealed the toxic potential of 2-naphthalene sulfonate to aquatic organisms thus stressed on the need for the implementation of stringent policies regarding the management of such toxic compounds.