ABSTRACT

2,3,7,8-Tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) has been associated with the manufacture of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), hexachlorophene, and other pesticides having 2,4,5-trichlorophenol as a precursor. The soil sample from the slough area at Shenandoah Stables contained the highest level of 2,3,7,8-TCDD (2,400 ng/g) in soil collected from Missouri. Solvent-extractable organic matter of soils was determined by extracting a suspension of 30 g of soil in 30 mL of an aqueous solution containing 30% NaCl and 2% KH2P04 with 30mL of methyl tert-butyl ether. The log soil concentration of 2,3,7,8-TCDD was positively correlated with the leachate concentrations. Soils exhibiting the general trend contained the greatest levels of 2,3,7,8-TCDD and chlorinated organic content as determined by peak area. The 2,3,7,8-TCDD applied to the soils from the Missouri region is alleged to have originated from chemical still bottoms which would most likely contain chlorinated benzenes and trich-lorophenols.