Children's Blood Pb Research Articles

Human exposure to heavy metals in the vicinity of Portuguese solid waste incinerators – Part 3: Biomonitoring of Pb in blood of children under the age of 6 years

As a part of environmental health surveillance programs related to Portuguese solid waste incinerators (SWI), two biomonitoring projects have been established to investigate additional exposure to lead in children under the age of 6 years living in the vicinity of those facilities. The above-mentioned programs, being the only ones in the country that integrate systematic observations on human exposure to heavy metals, have to provide systematic data from Portuguese regions on the extent and pattern of human exposure to heavy metals, namely to lead. The present paper is the third of a series of papers prepared to accomplish that objective in regards to lead exposure as evaluated by measuring lead levels in children under the age of 6 years. Altogether, 250 children from Lisbon and 247 from Madeira Island have already been involved in the investigation. The present study evaluates spatial and temporal trends of lead exposure, based on comparisons of children's blood lead levels, either stratified by living area (exposed and control groups), or by time of exposure (T0, the baseline time, and T1, after approximately 2 years of regular operation of the facilities). The results obtained correspond to a relatively reduced number of individuals. Possibly for this reason, they are not fully conclusive in relation to whether living in the vicinity of SWI represents an additional risk of higher exposure to lead. Time trends of lead exposure as evaluated by blood lead levels in children also do not show any clear pattern. These conclusions and the fact that altogether around 3% of children from the whole group have blood lead levels ⩾10 μg/dl warrant further investigation in order to clarify the contribution of incinerator emissions to the levels of lead in children and to identify alternative sources for preventive purposes, taking into consideration the relevance of even low lead exposure from a public health perspective, mainly in relation to children.

Determination of some heavy metals (Fe, Cu, Zn and Pb) in blood by total reflection X-ray fluorescence

The main purpose of this study is the interaction between nutrition (micronutrients heavy metals: Fe, Zn, Cu) and toxic heavy metals such as Pb in blood of children living in Gharb region of Morocco. This region receives all pollution carried by the Sebou river coming mainly from industrial activities. A rapid and simple analytical procedure was used for the determination of Fe, Cu and Zn trace amounts in blood by total-reflection X-ray fluorescence technique. This method is an energy dispersive XRF technique in a special geometry of primary beam, sample and detector. The sample is deposited on a plane polished surface of a suitable reflector material. It is presented as a few drops (25 μl) from a solution of blood digested in a mixture of HNO 3 and H 2 O 2 using a microwaves accelerated reaction system. The accuracy of measurements has been investigated by using certified materials. The concentration of Cu was found to be normal in all samples (≅ 1 ppm) which ruled out any interaction between this element and the others. On the other hand, amounts of Fe and Zn are very variables, suggesting an interaction between Fe and Zn. However, amounts of Pb in blood are inferior to 50 ppb, suggesting that no interaction exist with this metal and micronutrients.

Measuring Pb Bioavailability from Household Dusts Using an in Vitro Model

Despite an extensive cleanup program in the Port Pirie region, South Australia, the levels of lead (Pb) in blood of children have been found to exceed the level of concern (10 {micro}g/dL). The ingestion of household dust is a major pathway for elevated blood lead by children in the community. Significant differences in levels of Pb in blood in children were observed in various localities around the smelter. In this study an in vitro test was assessed as one method for determining the bioavailability of Pb in household dust and for predicting levels of Pb in blood of children. The solubility of Pb in the dust decreased significantly as pH of the in vitro mixture increased. Correlation studies with average blood Pb levels of children in the corresponding area and in vitro measures of Pb bioavailability found that the best relationship was with total dust Pb. A significant positive relationship was also found with Pb concentrations determined in the in vitro test at pH 3.0. This suggested that for these dust samples, which all had a similar environmental matrix, the use of the in vitro test was not a better indicator of blood Pb levels in children compared with amore » total Pb analysis.« less

PROBLEMS WITH LEAD (Pb) SCREENING IN SICKLE CELL DISEASE (SSD)

Serious Pb toxicity in 4 children with sickle cell anemia (SS) with blood Pb <80μg/dl prompted a search for asymptomatic Pb burden in a group of 30 children, age 3-18, with SSD (27 SS, 3 SC). Blood Pb and whole blood free erythrocyte protoporphyrin (FEP) were determined and the patients divided into 4 major Pb poisoning classes by correlating the results. (J. Pediatr. 87:824) 21 patients fit the criteria for class I, 6 for Ia and 1 for class IV. Two children with Pb levels <29μg/dl but FEP values > 190μg/dl do not fit the numerical classification. Pb/EDTA mobilization was done on 6 patients with FEP > 60μg/dl and blood lead < 40μg/dl who were demonstrated not iron deficient. Preliminary data shows abnormal Pb excretion in those children. In normal children blood Pb levels correlate with the FEP and clinical toxicity. However, in SSD an FEP > 60μg/dl can be associated with an increased Pb burden despite a blood Pb less than 40μg/dl.