Bioavailable Cadmium in Water, Sediment, and Fish, in a Highly Contaminated Area on the Thai-Myanmay Border

Abstract

Mae-Sot District in Tak Province is contaminated with high cadmium levels. Studies have found high concentrations of cadmium in rice fields and grain. People in this area have experienced high cadmium levels in their urine resulting in kidney problems. Cadmium concentrates in fish and shellfish by accumulating in their muscle tissue, and may result in posing a health risk to fish consumers. This study was to determine the magnitude of cadmium pollutants in water, sediment, fish and shellfish that have been found to cause adverse effects to humans. Water and sediment samples were collected from 9 sites along Mae-Toa creek. Six fish species and one shellfish species were caught from 3 sites along Mae-Toa creek. Seasonal variations in the bioavailable cadmium concentrations were observed. Rainy months were found to have higher cadmium concentrations than during dry months. Cadmium levels in the river sediment exceed the allowable standard. The highest concentrations of cadmium were detected in Swamp eel (0.27 mg/kg wet weight). Concentrations of cadmium in pond snail were 0.13 mg/kg-wet weight. According to human health risk assessment the hazard quotient (HQ) from eating Swamp Eel was 1.3 which is higher than one. As a result of this study, adverse health effects may occur and remediation is needed.