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Objectives: To determine blood lead and zinc protoporphyrin (ZPP) concentrations in a pediatric population, confirm their interrelationship at low blood lead concentrations, and assess changing trends through comparison of these data with those found in a similar population 10 years earlier and to US national values., Study Design and Methods: The study was conducted in a large pediatric hospital in the Washington DC area (CNMC) on patient whole blood specimens (n = 4908) (0-17 years) accrued from January 2001 to June 2002. Pediatric blood lead concentrations were determined by atomic absorption spectrophotometry, and ZPP by hematofluorometry. The data were analyzed using a computer adaptation of the Hoffmann approach., Results and Conclusions: Blood lead level (BLL) means ranged between 2.2 and 3.3 micro g/dL, and the median BLL was 3 micro g/dL throughout. Mean ZPP concentrations ranged between 21.1 and 26.6 micro g/dL and the median concentrations between 21 and 27 micro g/dL. In comparison to data obtained from a similar pediatric population at CNMC between 1991 and 1992, pediatric BLLs have significantly declined in the Washington DC area. The current data are also compared with data obtained from the National Health and Nutrition Examination Survey (NHANES III) of the US population. The interrelationship between ZPP and BLLs is examined.

Background: Lead exposure in young children may have adverse neurodevelopmental effects. Currently, an increased blood lead concentration is defined as >or=10 microg/dl for males and females of all ages, including children younger than 6 years. Using a large hospital population (n=11145), we define more specific ranges for pediatric blood lead concentrations., Methods: Pediatric blood lead concentrations were determined (atomic absorption spectrophotometry) on patient samples accrued from January 2001 to June 2002, and the data was analyzed employing the Hoffman approach., Results: For lead, the 2.5th and 97.5th percentiles for subjects aged 0 to 12 months were 2.3 to 4.7 microg/dl for females and 1.8 to 4.9 microg/dl for males. The 97.5th percentiles increased for the 1-2 years age group both for females (5.2 microg/dl) and males (5.6 microg/dl). There was a significant decrease in blood lead concentrations after age 10 years, the 97.5th percentile being 4.4 microg/dl in both female and male subjects. The values in all corresponding age groups were similar for females and for males. The medians of all age groups were similar for females and for male subjects., Conclusion: The blood lead concentrations are much lower compared to previously published data.

The developing central nervous system (CNS) is more vulnerable to injury than the adult one. Although a great deal of research has been devoted to subtle effects of developmental exposure, such as neurobehavioral changes, this review instead focuses on a number of chemicals that have been shown, in several experimental models as well as humans, to cause morphological changes in the developing nervous system. Chemicals that are discussed include methylmercury (MeHg), lead (Pb), antiepileptic drugs, and ethanol. Additionally, the issue of silent neurotoxicity, i.e., persistent morphological and/or biochemical injury that remains clinically unapparent until later in life, is discussed. [ABSTRACT FROM AUTHOR]