HEAVY METAL POISONING AND DEMOGRAPHIC PATTERNS IN METAL RECYCLING WORKERS AT VAN MON, YEN PHONG, BAC NINH PROVINCE The study is conducted from January 2013 to May 2013 on 600 workers (18 - 60 years old), who worked in the metal recycling facility for 12 months or more, directly involved in collecting or metallurgical process at 40 metal recycling facilities at Van Mon, Yen Phong, Bac Ninh.