Neurotoxicity produced by developmental exposure to PCBs

Abstract

Polychlorinated biphenyls (PCBs) are a family of chlorinated hydrocarbons that are ubiquitous in the environment. Many of them have very long half-lives in humans and other animals and can be detected in biological tissue in most people in industrialized countries. Incidents of poisoning from rice oil contaminated with PCBs in Japan and Taiwan revealed hypotonicity and cognitive deficits in infants and children exposed in utero in the presence of other signs of toxicity, including low birth weight, abnormal pigmentation, and swollen gums and eyelids. Prospective studies in Michigan and North Carolina revealed decreased reflexes and retarded psychomotor development during infancy and early childhood associated with in utero PCB exposure. The Michigan study also revealed decreased IQ and reading ability when children were 11 years old. A recent study in the Netherlands also reported decreased reflexes and retarded psychomotor development during infancy, but deficits were largely related to breast milk rather than maternal or cord blood PCB levels. Research in monkey and rat models has also revealed changes in activity and cognitive function as a result of developmental exposure to PCBs. The available data support the hypothesis that PCB levels typically observed in individuals in industrialized countries may result in neurotoxicity in the offspring. Published 1997 Wiley-Liss, Inc. MRDD Research Reviews 1997;3:223–229. © 1997 Wiley-Liss, Inc.