Yearly measurements of blood lead in Swedish children since 1978: the declining trend continues in the petrol-lead-free period 1995-2007.

BACKGROUND: We have measured blood lead concentrations (B-Pb) in Swedish children, yearly since 1978. As reported previously, a substantial decrease of B-Pb was found for the period 1978-1994 (2440 children measured), as an effect of gradual reduction of lead in petrol. In another report focusing on the petrol-lead-free period 1995-2001, we noted that B-Pb seemed to stabilize at an average level close to 20 microg/L.
OBJECTIVE: We here analyze data from the extended petrol-lead-free period 1995-2007.
METHODS: B-Pb was measured in 1268 children, aged 7-11 years, from the municipalities of Landskrona and Trelleborg in southern Sweden, yielding 1407 measurements on B-Pb (since 139 children were measured in two different calendar years).
RESULTS: We observed statistically significant decreases of the average concentrations during the recent years. The average B-Pb reduction rate was close to 5%/yr in the petrol-lead-free period 1995-2007; a similar reduction rate was estimated for the period with gradual reduction of lead in petrol, 1978-1994. The most recent geometric mean of B-Pb was 13.1 (range, 6.9-29.1)microg/L in Trelleborg (sample year 2005) and 13.2 (5.7-58.5)microg/L in Landskrona (2007). A declining B-Pb time trend was observed during the recent years among children who lived in near smelter, urban, and rural residential areas, respectively. B-Pb was influenced by the variables sex (boys had higher B-Pb), parents' smoking habits (children with one or both parents smoking had higher B-Pb), and potentially lead-exposing hobbies (for example, shooting air guns).
CONCLUSION: Children's B-Pb levels can continue to decline markedly more than a decade after lead in petrol has been phased out in a country.