US EPA

2181121 

Journal Article 

Silo sealents as a source of polychlorobiphenyl (PCB) contamination of animal feed 

Skrentny, RF; Hemken, RW; Dorough, HW 

1971 

Yes 

Bulletin of Environmental Contamination and Toxicology
ISSN: 0007-4861
EISSN: 1432-0800 

NIOSH/00080825 

6 

5 

409-416 

English 

5005170 

Silo sealants were analyzed as a source of polychlorinated-biphenyl (1336363) (PCB) contamination in animal food. Since residues of PCB's may interfere with detection and analysis of certain organo-chlorine pesticides, this study examined the level and distribution of PCB contamination in corn silage and wall chips from several silos believed to be coated with sealents containing PCB's. Tests were conducted on the solubility of PCB's in water and silage water extract. A standard hexane (110543) solution of Aroclor-1254 (11097691) was used for these studies. PCB's were extracted from a 25g sample of corn silage and analyzed by gas chromatography. It was established that DDT (50293) and its analogs did not interfere with PCB analysis. Six silage samples were taken at various distances from the walls. Chips were taken from six points along the exposed wall, then ground, and tested. Gas chromatographic analysis showed that the chips did contain Aroclor-1254 residues. In the silage, the greatest amounts of residues were in material collected within 6 inches of the wall. Residues declined quickly as the distance from the wall increased and none were detected in samples taken 4 to 6 feet from the silo wall. Samples taken 0 to 2 inches from the wall contained highest residues. Laboratory experiments suggest that PCB's from silo wall chips would contaminate silage through liquor which moves along the wall and downward, spreading the PCB's over a wide area. Automatic feeding devices inside the silo may increase Aroclor contamination. In all but one sample analyzed, components of the Aroclor-1254 mixture appeared to contaminate the silage in an equal manner.