Higher Chlorinated Dioxins Implicated in the Mortality of Young Pigs Kept on a Pentachlorophenol-treated Wooden Floor.

Young pigs raised on a pentachlorophenol-treated wooden floor showed a high mortality. The deaths ceased when the original treated wood was covered with untreated plywood. Analysis of the wood, mother's milk, and young pig tissues was carried out for pentachlorophenol and chlorinated dibenzo-p-dioxins. Pentachlorophenol was found in the wood and mother's milk but not in the young pig tissues. Concentrations of the higher chlorinated dioxins were found in the wood at the ppm level, in the mother's milk at the low ppt level and in the skin and liver of the young pigs at the ppb level. A comparison of the concentrations of hexa-and hepta-dioxin isomers in the wood, and in the piglet skin and liver indicated that a selective absorption and/or metabolism of these isomers had occurred. The results of this case history implicate the higher chlorinated dioxins in the mortality of the young pigs and underline the danger of using technical pentachlorophenol for wood treatment in association with food producing animals.