Delta-Aminolevulinic Acid Dehydratase, Low Blood Lead Levels, Social Factors, and Intellectual Function in an Afro-Brazilian Children Community

Delta-aminolevulinic acid dehydratase (ALAD) enzyme catalyzes the second phase of the heme biosynthesis and is involved in lead toxicokinetics. This research aimed to evaluate its influence on the relationship between blood lead (PbB) levels and intellectual performance in Afro-Brazilian children. PbB, hemoglobin concentration, ALAD activity, and polymorphism were determined in whole blood. Anthropometric, socioeconomic, and family environment stimuli data were collected with appropriate instruments. The non-verbal intelligence of children and their mothers or guardians was assessed using the correspondent Raven's Progressive Matrix versions. The medians (range) of PbB levels and ALAD activity were 1.0 μg/dL (0.1-21.3) and, 71 U/L (31-113), respectively. ALAD G177C was distributed as follows: 97.9% for ALAD1/1 and 2.1% for ALAD1/2 genotypes. The mean of Raven raw score was 19.3 (± 5.6) points and there were no differences according to sex or environmental Pb exposure. No statistically significant association was observed between PbB level and children's IQ. However, ALAD activity presented an inverse significant association with PbB levels, children's percentile IQ, and children's IQ/Age ratio, suggesting a neuroprotective role of ALAD1 genotype in those with low PbB level.

Assessment of potters' occupational exposure to lead and associated risk factors in Maragogipinho, Brazil: preliminary results

BACKGROUND AND PURPOSE

Lead (Pb) is used as a flux in the glazing process of pottery utensils in several regions of the world. It can affect the nervous and hematopoietic systems; in addition, it is classified as a probable human carcinogen. This work aims to evaluate Pb exposure of potters and describe the main determinants of elevated blood Pb (PbB) levels in this group of workers.

METHODS

This is a cross-sectional study with potters of Maragogipinho Village, Bahia, Brazil, of both sexes, aged 16-72 years (n = 85). Non-exposed workers of the same age range residing in the urban area of Aratuípe town were also recruited (n = 50). We evaluated Pb dust deposition rates (PbDrt) in pottery workshops and PbB levels. All Pb measurements were performed by Graphite Furnace Atomic Absorption Spectrometry.

RESULTS

The median of PbB (min-max) and geometric mean (SD) PbDrt for the exposed group were 7.9 (0.9-49.8) µg/dL and 1463 (± 290,000) μg/m²/30 days, respectively. For the control group, levels were 1.5 (0.1-19.8) μg/dL and 82 (46) μg/m² 30 days, respectively.

CONCLUSION

The data found showed an excessive exposure among artisans, exceeding occupationally safe levels and those reported in the literature. It is important to implement occupational hygiene measures and improvements of the working conditions of these labors, especially the replacement of lead oxide in the pottery-glazing process.

Environmental exposure to lead and hematological parameters in Afro-Brazilian children living near artisanal glazed pottery workshops

This study aimed to evaluate the exposure to environmental lead (Pb) of children from a traditional community of African descent in Brazil and the effects on hematological parameters. Children (n = 75) aged 5.5-13 years from the exposed areas classified as low (LEx) and moderately (MEx) exposed were compared with children (n = 75) of a control group (CG). Dust Pb loading rates (RtPbs) at children's homes were measured. Peripheral venous blood samples were collected to assess Pb biomarkers of exposure and effects. All Pb determinations were performed by graphite furnace atomic absorption spectrometry. The median (IQR) of RtPb, PbB level, and ALA-D activity were 65 (25-137) μgPb/m²/30 days, 1.0 (0.1-2.8) μg/dL, and 71 (55-86) U/L, respectively. Spearman correlation evidenced the relationship of PbB with RtPb (rho = 0.368, P < 0.001) and ALA-D activity (rho = -0.587; P ˂ 0.001). After adjusting for exposure degree and child's age, a decline of 7.4 U/L in ALA-D activity was associated with a 10-fold increase in PbB. The prevalence ratio of elevated PbB (>5 μg/dL) in LEx and MEx areas were 1.5 and 3.7, respectively. Indoor dust exposure, living near pottery workshops and the secondary exposure were the main determinants of elevated PbB levels, which were associated with hematological effects.

Environmental Co-Exposure to Lead and Manganese and Intellectual Deficit in School-Aged Children

Studies have demonstrated that, for urban children, dust represents the main exposure to sources of metals like lead (Pb) and manganese (Mn). We aimed to investigate the exposure to these metals and their association with intellectual deficit in children living in an industrial region. This cross-sectional study recruited volunteers from four elementary schools in the town of Simões Filho, Brazil. We evaluated 225 school-aged children (7⁻12 years) for blood lead (PbB) and manganese hair (MnH) and toenails (MnTn) by graphite furnace atomic absorption spectrometry. Child and maternal IQs were estimated using the Wechsler Abbreviated Scale for Intelligence (WASI). Median and range PbB were 1.2 (0.3⁻15.6) μg/dL. MnH and MnTn medians (ranges) were 0.74 (0.16⁻8.79) μg/g and 0.85 (0.15⁻13.30) μg/g, respectively. After adjusting for maternal IQ, age and Mn exposure, child IQ drops by 8.6 points for a 10-fold increase in PbB levels. Moreover, an effect modification of Mn co-exposure was observed. In children with low MnTn, association between Pb and child IQ was not significant (β = -6.780, p = 0.172). However, in those with high MnTn, the association was increased by 27.9% (β = -8.70, p = 0.036). Low Pb exposure is associated with intellectual deficit in children, especially in those with high MnTn.