soil samples were collected from 28 fields which had received manure from michigan 's most highly contaminated dairy herds . 
 the number of fields in each concentration range of pbb in soil were : 2 , not detectable ; 15 , 0.0 to 8.0 ppb ; 6 , 14 - 102 ppb , and 5 , 153 to 371 ppb . 
 plant tissue sampled from the 10 most highly contaminated fields contained no detectable pbb . 
 no evidence of significant degradation of pbb was noted after 1 year incubation in soil . 
 when 14c hexabromobiphenyl and heptabromobiphenyl isomers were incubated in soil less than 0.2% of the 14c was volatilized . also gas chromatographic analysis of soil extracts showed no difference in recovery of the six major pbb isomers between sterilized and nonsterilized soil . 
 analysis of these extracts by thin layer chromatography and autoradiography showed no 14c - pbb intermediates . 
 photodegradation products of the major hexa- and heptabromobiphenyl isomers showed more but still minor ( approximately 3% ) biodegradation in soil . 
 much of the photodegradation products appeared bound to soil , since these products could not be extracted from soil . 
 photodegradation does not appear to be a significant fate of pbb in manures spread on fields since no change was noted in the relative concentrations of isomers in soil samples from our field survey . 
 studies with distilled , tap , river , and soil waters showed that pbb solubility was markedly influenced by water composition.imagesfigure 1.figure 2 .