Health Risk Management for Cadmium Contamination in Thailand : Are Challenges Overcome

This report addresses the challenges encountered and, to a certain extent, overcome, while health risk assessment and management were being conducted in Mae Sot, Thailand following cadmium contamination to rice, the main diet of Thais. In November 2003, Department of Agriculture (DOA), Ministry of Agriculture (MOA) sent a summary report of a 6-year study revealing serious contamination of cadmium to soil and rice grown in the vicinity of a large zinc mine to Department of Pollution Control (DPC). The report concluded that level of rice contamination warranted immediate attention to prevent cadmium poisoning among the exposed population. A team of DPC experts initiated a risk assessment plan and Department of Disease Control (DDC) was among the 6 central governmental offices contacted to join this effort. Department of Disease Control (DDC) staffs and Mae Sot Hospital team initiated a rapid survey to assess exposure situation among the 100,000 residents in the affected municipality. Using GIS data, health staffs mapped contaminated rice fields with consumers. By the end of 2004, affected population was classified according to their exposure statuses. Toxicologists from Chiang Mai University Medical School and Japanese cadmium experts from Kanazawa Medical University started a research project to assess the effect of cadmium on kidneys, the major target organ of cadmium. It is expected that a 10-year surveillance is needed to reduce health risks among 800 people, who had high urinary cadmium level (> 5 μg/g creatinine) and were at risk of having cadmium-induced renal failure, to acceptable level. Challenges encountered during health risk management included; unclear source of contamination, between natural and man-made origins, rendering it difficult to claim accountability from the sole zinc mine, discontinuation of rice growing on contaminated land against local cultural beliefs, compensation for rice growing without alternative crops cultivation solution, and human rights issues for Karen population in the affected area. All these issues prompt public staffs to search for alternative ways to manage health risks more economically, socially and culturally acceptable.