Chemical contamination of free-range eggs from Belgium.

The elements manganese, cobalt, nickel, copper, zinc, arsenic, selenium, molybdenum, cadmium, antimony, thallium, lead and mercury, and selected persistent organochlorine compounds (dioxins, marker and dioxin-like polychlorinated biphenyls, dichlorodiphenyltricholroethane (DDT) and metabolites as well as other chlorinated pesticides) were analysed in Belgian free-range eggs obtained from hens of private owners and of commercial farms. It was found that eggs from private owners were more contaminated than eggs from commercial farms. The ratios of levels in eggs from private owners to the levels in eggs from commercial farms ranged from 2 to 8 for the toxic contaminants lead, mercury, thallium, dioxins, polychlorinated biphenyls and the group of DDT. DDT contamination was marked by the substantial presence of p,p'-DDT in eggs from private owners in addition to dichlorodiphenyldichloroethylene (p,p-DDE) and dichlorodiphenyl-dichloroethane (p,p'-DDD). It is postulated that environmental pollution is at the origin of the higher contamination of eggs from private owners. Extensive consumption of eggs from private owners is likely to result in toxic equivalent quantity intake levels exceeding the tolerable weekly intake.