food as a source of dioxin exposure in the residents of bien hoa city, vietnam. | recently, elevated dioxin levels, over 5 parts per trillion (ppt) 2,3,7,8-tetrachlorodibenzo-p-dioxin (tcdd), from agent orange was reported in 95% of 43 selected residents of bien hoa city, a city in southern vietnam near a former air base used for agent orange-spraying missions. agent orange herbicide, contaminated with tcdd, was sprayed in vietnam between 1962 and 1971 primarily for use as a defoliant. typical blood tccd levels are 2 ppt in vietnamese, but levels are as high as 413 ppt in bie ... | 2003 | 12915779 |