EFFECTS OF SEVERAL ELECTRON-DONORS ON TETRACHLOROETHYLENE DECHLORINATION IN ANAEROBIC SOIL MICROCOSMS

Anaerobic microcosms of subsurface soils from three location were used to investigate the separate effects of several electron donors on tet rachloroethylene (PCE) dechlorination activity. The substrates tested were methanol, lactate, acetate and sucrose. Various levels of sulfate -reducing, acetogenic, fermentative, and methanogenic activity were ob served in all sediments. PCE dechlorination was detected in all microc osms, but the amount of dehalogenation varied by several orders of mag nitude. Trichloroethylene as the primary dehalogenation product; howev er, small amounts of cis-1,2-dichloroethylene, 1,1-dichloroethylene, a nd vinyl chloride were also detected in several microcosms. Lactate-am ended microcosms showed large amounts of dehalogenation in two of the three sediments. One of the two sediments which showed positive activi ty with lactate also had large amounts of dehalogenation with methanol . Amendment with formate, acetate, or sucrose resulted in only slight dehalogenation in the three sediments. Elevated levels of dehalogenati on were not consistently associated with any observable anaerobic meta bolisms (sulfate reduction, acetogenesis, fermentation, or methanogens is). (C) 1997 Elsevier Science Ltd.