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Sources of variation and some principal determinants of blood lead concentration (PbB) were investigated in a cohort of children, followed to age 5 y, who were born near a lead smelter in Port Pirie, South Australia. The child's age and place of residence were the two variables most strongly predictive of PbB. A sharp increase in PbB occurred between 6 and 15 mo of age and was followed by a peak concentration that occurred at approximately 2 y of age, after which PbB steadily and consistently declined. Irrespective of age, the PbBs in children who lived in Port Pirie were significantly higher than levels identified in children who resided outside the city. There was no significant difference in PbB between boys and girls. Elevated PbB at each specific age was associated mainly with increased lead concentrations in the topsoil of the local residential area, employment of the father in the lead industry, parental smoking, and behaviors likely to cause ingestion of dirt. Blood samples taken from children at certain ages and during the warmer months contained more lead than samples obtained during the cooler months. The effects of these determinants on PbB during early childhood were basically consistent in both single and multivariable analyses., The Adverse Effects of excessive lead exposure on the intellectual, cognitive, and behavioral development of young children have received increased attention during the past decade.[1-3] Definitive evidence of neuropsychological effects [...]

Early childhood exposure to environmental lead may result in subtle deficits in neuropsychological development. Most studies, however, have reported global measures of development, and the findings have not been consistent. In this report, we examine the association between blood lead concentration and a specific aspect of neuropsychological development, visual-motor integration. Each child in a cohort of 494 children living in and around the lead smelting town of Port Pirie, South Australia, was followed for its first 7 years of life. Serial blood samples were collected at various ages to estimate the lifetime burden of each individual. At the time of each blood sampling, systematic information was obtained on a wide range of other variables relevant to child development. We evaluated visual-motor integration at age 7 with the Beery Developmental Test of Visual-Motor Integration (mean score: 13.4). There was an inverse relation between blood lead concentration and visual-motor performance. After adjustment for potential confounding factors, both prenatal and postnatal blood lead concentrations exhibited a dose-related inverse association with children's visual-motor performance. For an increase in lifetime average blood lead concentration from 10 μag per dl (0.48 μmol per liter) to 30 μg per dl (1.45 μmol per liter), the estimated deficit in children's visual-motor performance was 1.6 points (95 confidence interval 0.3–2.9). The results indicate that visual-motor integration may be a more sensitive index than global measures of development, such as intelligence quotient, for the assessment of lead effects on child development.

In the context of a wider prospective investigation into the effects of cumulative exposure to lead, in uteroand postnatally, on the outcome of pregnancy and growth and development in early childhood, 831 pregnant women who were living in Port Pirie, South Australia, the site of Australia's largest lead smelter, were recruited between May 1979 and May 1982, and the various factors that were likely to influence their blood lead concentration were examined. No significant difference in blood lead level was found among different stages of pregnancy. Higher concentrations of blood lead were measured in women who resided in areas of high soil lead content and in women who had resided in Port Pirie for three or more years. A low socioeconomic status, the use of water from the reticulated water supply rather than rainwater, an age of 21 years or less, a high body mass index, a low dietary intake of calcium, and cigarette smoking were all factors that were associated with a higher blood lead concentration. Lower blood lead concentrations were observed in women who took iron and folic acid to supplement their diet. Multiple regression analysis of average antenatal blood lead levels confirmed most of the univariate associations.

A cohort of over 600 children who were born between 1979 and 1982 and accounted for the great majority of all births in Port Pirie, South Australia, and its immediate environs, underwent capillary blood sampling at the ages of 6 months, 15 months, 2 years, and annually thereafter. The mean blood lead concentration (Pb‐B) initially rose markedly, peaked at 2 years of age, and subsequently declined gradually at 3 and 4 years of age. No differences in Pb‐B were observed between girls and boys. Secular trends in Pb‐B at the age of 2 years that were observed in blood samples taken over the 1981‐1984 period suggest that both the drought of 1982 and changes in community behaviour may have accounted for some of the age‐related variation. The Pb‐B was associated positively with surface soil lead concentrations, with a two‐fold variation in mean Pb‐B between residential zones within Port Pirie. Pb‐B was higher in summer than in winter months at the ages of 6 and 15 months, but not at older ages. These findings suggest that lead in dust influences strongly blood lead concentrations in early childhood.