Impairment of psychological functions in children environmentally exposed to lead.

The major objective of the study was to determine whether environmental exposure to lead exerts a negative impact upon psychological functions in children. The examined group consisted fo school age children (6-15 years old, x = 9.5, SD = 1.4) living close to copper works. Out of 4548 children with measured blood lead concentrations, two groups were selected one with the highest exposure levels (12.0-27.2 micrograms/dl) and the other drawn from the remaining children, with low blood lead levels. The mean exposure level for the whole examined group equalled 10.18 mu/dl PbB (SD-4.73 micrograms/dl). To assess effects of the exposure, the following variables were measured in the examined children: intelligence, hand-eye coordination, perception, memory, reaction time and accuracy, and behaviour disorders. The moderator variables of sociodemographic character, i.e. parents' education, income, etc., were also controlled. A significant impact of lead upon psychological functions and behaviour was revealed for two variables only: intelligence and attention concentration. An increase in the exposure level by 10 micrograms/dl PbB was associated with deterioration of general IQ by 5.3 points and growth of the number of mistakes in the Simple Reaction Time test by 3.3. It was also revealed that the short-term memory deteriorates with growing level of exposure, the strength of this relationship was close to the level of statistical significance (p < 0.07).