1. Department of Community Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand;
2. School of Medicine, University of Phayao, Phayao, Thailand;
3. Toxicology Unit, Department of Forensic Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand;
4. School of Environmental Health, Institute of Public Health, Suranaree University of Technology, Nakhon Ratchasima, Thailand