Perchlorate contamination assessment and hypothyroidism in rat studies using water samples collected around Kovil Patti, Tuticorin District of Tamil Nadu, India

Abstract

Perchlorate is well recognized as a persistent and pervasive contaminant of water supplies in the manufacture area of explosives, fireworks, match box and rocket fuel industries. Perchlorate is of major concern because of uncertain nature in the toxicological database available to address the potential health effect in animals and humans. Perchlorate is known to disturb the hypothalamus-pituitary-thyroid (HPT) by competitively inhibiting the iodide uptake in the thyroid gland, which potentially leading to hypothyroidism. The present study assessed the contamination level of perchlorate mainly along with the chlorate and nitrate ion present in soil debris, well water and sewage sludge samples from fireworks, safety matches manufacturing industry areas in Kovilpatti, Tuticorin District. Perchlorate ion in bore well water and soil samples were qualitative and quantitatively analysed by using various Physico-chemical analytical techniques. The observed maximum contamination values of perchlorate ion in sewage water collected near to the firework waste dump yard (BWWS-1) and water sample extracted from 100 g of soil collected by firework waste (BWDS-5) were found to be 98.8 and 97.3 mg/L respectively. The BWWS-1 water sample used to examine the hypothyroidism in rat by intravenous injection of 3 ml/day for 5, 10, 15 and 20 days by measuring the T4 hormones level in the blood plasma. A notable decreasing trend was observed. However, for 10 days exposure the plasma T4 concentrations was reduced to nearly half (291 µg/dl) in compared with control (630 µg/dl). These studies provide strong evidence that the hypothyroidism behavior data obtained from rat should critically affect the developmental and behavioral problems of infants and children around the study area.