Dealing with lead in Broken Hill--trends in blood lead levels in young children 1991-2003.

The objective of the study was to investigate trends in blood lead concentrations in preschool children between 1991 and 2003, as part of the evaluation strategy of a public health lead management program in Broken Hill, Australia. Since 1991, all Broken Hill children aged 1-4 years have been offered at least annual blood lead screening as part of a community-wide lead management program. Recruitment of children was promoted throughout the period using local media and distribution of promotional material from health care centres and preschool, childcare, and educational facilities around the city. Venous blood samples were collected using standard procedures and analyses were subjected to internal and external quality control programs. Because the frequency distribution of blood lead levels are skewed, geometric rather than arithmetic means were used for comparative purposes. Trend analysis was based on age and sex standardised mean blood lead levels. The number of 1- to 4-year-old children screened ranged between 496 and 948 in any one year and response rates varied between 39% and 73%. The age-sex standardised mean blood lead level decreased from 16.3 microg/dL to 7.1 microg/dL between 1991 and 2003. Overall, blood lead levels declined by 56% over 13 years. These reductions were consistently observed irrespective of age or where a child lived in the town. The rate of decline has slowed since 1997. We conclude that substantial progress has been made in dealing with the lead problem in Broken Hill children, although the rate of decline of blood lead levels has slowed. Continued public health action is still needed to bring the proportion of young children with significantly elevated blood lead levels (>15 microg/dL) down from the 2003 figure of 12% to the NHMRC community-based target for lead in young Australians of 5%.