Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans in cattle raised at agricultural research facilities across the USA and the influence of pentachlorophenol-treated wood

Abstract

Adipose tissue samples from 158 cattle raised locally at experiment stations across the USA were analysed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F). While 80% of the samples had PCDD/F concentrations that fell within the range of a previous US survey of beef animals (not detected −4.1 ppt toxic equivalency), several animals had exceptionally high concentrations (8–54 ppt toxic equivalency). The investigations of three facilities where highly contaminated animals were raised found pentachlorophenol-treated wood at each site. The congener pattern in the animals’ tissues and the lack of elevated PCDD/F levels in other environmental samples, i.e. hay and soil, indicated that the treated wood was the source of contamination. A congener pattern similar to that of pentachlorophenol-exposed animals was seen for the means and medians of the entire data, i.e. OCDD, HpCDD and 1,2,3,6,7,8-HxCDD dominated, the PCDD concentrations equalled or exceeded the furan concentrations, and the concentration of 1,2,3,6,7,8-HxCDD was six times that of the other HxCDD isomers. This suggested that pentachlorophenol-treated wood contributed measurably to many of the animals in this survey. The largest contributors to the median toxic equivalencies were 1,2,3,7,8-PeCDD (40%) and 1,2,3,6,7,8-HxCDD (16%). No clear geographical trends emerged from the data.

Keywords:

• polychlorinated dibenzo-p-dioxins
• polychlorinated dibenzofurans
• cattle
• pentachlorophenol
• treated wood

Acknowledgements

The authors recognize the technical assistance of Kristin McDonald and Jean Picard in the preparation of the samples for dioxin analysis. They thank their collaborators at the experiment stations for their participation in the collection of samples. The use of trade, firm or corporation names in this paper is for the information and convenience of the reader. Such use does not constitute an official endorsement or approval by the US Department of Agriculture or the Agricultural Research Service of any product or service to the exclusion of others that may be suitable.