EFFECTS OF ALTERNATIVE ELECTRON-DONORS, ACCEPTORS AND INHIBITORS ON PENTACHLOROPHENOL DECHLORINATION IN SOIL

The potential dechlorination of pentachlorophenol (PCP) in soil by a D CP-adapted consortium was investigated Results show that PCP dechlorin ation was enhanced under sulfate reduction and methanogenic conditions , but inhibited under denitrifying conditions within a 20-day incubati on period. Under those same three conditions we also found that PCP de chlorination was enhanced by the addition of lactate, pyruvate, and ac etate, but delayed by the addition of manganese oxide and inhibited by the addition of ferric chloride. In addition, our results failed to s how any relationship between PCP dechlorination and oxidation-reductio n potential (ORP) or changes in pH values. Treatment with lactate caus ed the greatest increase in methane production, the highest rates of s ulfate or nitrate consumption; adding manganese oxide led to the secon d greatest increase, and the addition of ferric chloride the least. Th e addition of methylphenols and nitrophenols were found to inhibit PCP dechlorination. Methanogen may have constituted the major dechlorinat ion population in our experimental consortium. Copyright (C) 1996 Else vier Science Ltd