Neurobehavioural investigations in adolescents exposed to environmental pollutants

Environmental exposures to industrial pollutants have been associated with lowered intelligence and behavioural problems. The Flemish Environmental and Health Study focussed on biomonitoring of exposure and associated health effects. This part of the study investigated neurobehavioural performance in adolescents in relation to lead (blood Pb), cadmium (urine Cd), polychlorinated biphenyls (PCB concentration of congeners 138, 153 and 180) and compounds with 'dioxin-like' activity (measured by the CALUX-assay). One-hundred and twenty girls and 80 boys (mean age 17.4 years) were enrolled. The NES battery was used to assess simple reaction time, switching attention, digit span forward, hand-eye coordination and symbol-digit substitution (SDS). Multiple regression analysis was performed to study dose-effect relationships between the neurobehavioural outcome variables and the exposure parameters in boys and girls. Slowing of SDS with increasing logPbB and logCdU was seen in boys only (PbB 39-1549nmol/L, CdU 0.02-0.40nmol/mmol creatinine). No dose-effect relations were found with serum PCB concentrations or CALUX-TEQs. Only one of several tests showed a performance decrease related to given environmental exposures to heavy metals. Further studies are needed to clarify whether the pattern of results reflects gender effects or the different exposure characteristics of boys and girls in our study.