Polychlorinated biphenyls, organochlorine pesticides and neurodevelopment.
OBJECTIVE
Although environmental levels of polychlorinated biphenyls and certain organochlorine pesticides--hexachlorobenzene, dichlorodiphenyl trichloroethane and its primary metabolite, dichlorodiphenyl dichloroethene--are generally on the decline, early-life exposures to these prevalent contaminants continue. The review will describe current understanding of the potential neurodevelopmental consequences of low-level exposures to these contaminants.


RESULTS
Animal models suggest that early-life exposures to polychlorinated biphenyls, dichlorodiphenyl trichloroethane/dichlorodiphenyl dichloroethene or hexachlorobenzene are associated with decreased cognitive or behavioral function in later development. Despite almost 30 years of research, however, results of human studies are inconsistent regarding the nature of the observed effects and their persistence over time. Overall, epidemiologic studies support modest associations of primarily prenatal polychlorinated biphenyl exposures with differences in neuromotor development, decrements in cognition and behavioral deficits, particularly regarding attention and impulse control. There are limited published human data regarding potential neurodevelopmental toxicities of early-life exposures to dichlorodiphenyl trichloroethane/dichlorodiphenyl dichloroethene and hexachlorobenzene.


CONCLUSIONS
Exposures to polychlorinated biphenyls, dichlorodiphenyl trichloroethane/dichlorodiphenyl dichloroethene and hexachlorobenzene are likely detrimental to neurodevelopment. Effective control of exposure is complicated by variable exposure sources and variable contaminant levels in food, particularly fish, for which it is important to balance the risk of contaminants with nutritional benefits.
Korrick
Susan A
SA
Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA. susan.korrick@channing.harvard.edu
Sagiv
Sharon K
SK
D002648:Child; D002653:Child Behavior Disorders / Q000139:chemically induced* / Q000175:diagnosis; D015331:Cohort Studies; D002658:Developmental Disabilities / Q000139:chemically induced* / Q000175:diagnosis; D004781:Environmental Exposure / Q000032:analysis; D004785:Environmental Pollutants / Q000633:toxicity; D005260:Female; D006581:Hexachlorobenzene / Q000633:toxicity*; D006801:Humans; D009483:Neuropsychological Tests; D010575:Pesticides / Q000633:toxicity*; D011078:Polychlorinated Biphenyls / Q000633:toxicity*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011446:Prospective Studies
D004785:Environmental Pollutants; D010575:Pesticides; D006581:Hexachlorobenzene; D011078:Polychlorinated Biphenyls