Blood lead in the 21st Century: The sub-microgram challenge

Trends in neurodevelopmental disability burden due to early life chemical exposure in the USA from 2001 to 2016: A population-based disease burden and cost analysis

Endocrine disrupting chemicals are known to cause neurodevelopmental toxicity through direct and indirect pathways. In this study we used data from the National Health and Nutrition Examination Surveys, along with known exposure-disease relationships, to quantify the intellectual disability burden attributable to in utero exposure to polybrominated diphenyl ethers (PBDEs), organophosphates, and methylmercury and early life exposure to lead. We also estimated the cost of the IQ points lost and cases of intellectual disability. PBDE exposure was the greatest contributor to intellectual disability burden, resulting in a total of 162 million IQ points lost and over 738,000 cases of intellectual disability. This was followed by lead, organophosphates, and methylmercury. From 2001 to 2016, IQ loss from PBDEs, methylmercury, and lead have decreased or remained stagnant. Organophosphate exposure measurements were only available up to 2008 but did show an increase in organophosphate-attributable IQ loss. Although most of these trends show benefit for children's neurodevelopmental health, they may also point towards the use of potentially harmful substitutions for chemicals that are being phased out.

Size-resolved Pb distribution in the Athabasca River shows snowmelt in the bituminous sands region an insignificant source of dissolved Pb

Lead (Pb) is a metal of special importance because of its long history of commercial and industrial use, global atmospheric contamination accelerated by the use of gasoline additives, and health effects, with children being especially vulnerable. Global atmospheric Pb pollution reached its zenith in the 1970’s, but subsequent impacts on freshwater aquatic systems are poorly understood. Employing metal-free sampling and handling protocols, we show that snowmelt from the Athabasca bituminous sands region is an insignificant source of dissolved Pb to the Athabasca River (AR). Total Pb in the AR is low, and almost entirely in particulate form. Lead in the suspended solids in the AR exactly follows thorium (Th), a conservative lithophile element, and a linear regression of Pb against Th (Pb = 1.6 × Th + 0.0; R² = 0.99) yields a slope identical to the Pb/Th ratio in the Upper Continental Crust. In the “dissolved” fraction, the Pb/Th ratio is equivalent to that of deep, open ocean seawater; and dominated by colloidal forms. Taken together, these results show that the efforts of recent decades to reduce anthropogenic Pb to the environment have been successful: Pb loading to the river can now be explained predominantly by natural processes, namely erosion plus chemical weathering.

The relation between occupational exposure to lead and blood pressure among employed normotensive men

BACKGROUND

Lead is a pollutant with numerous adverse effects on health. Since it can affect blood pressure, peripheral blood vessels, and the heart, the present study aimed to evaluate the relation between occupational exposure to lead and blood pressure.

MATERIALS AND METHODS

This cross-sectional study included male individuals working in battery firms in Isfahan. A questionnaire covering demographic characteristics and the history of different diseases and occupational exposure to lead was completed. Each participant's blood pressure was also measured and recorded. After obtaining blood samples and determining lead levels, mean and frequency analyses were performed. In addition, Pearson's correlation test and linear regression were used to assess the relation between blood lead levels (BLLs) and systolic and diastolic blood pressure. All analyses were performed in SPSS.19.

RESULTS

The mean age of the 182 studied workers was 42.85 ± 13.65 years. They had worked in battery firms for a mean period of 23.67 ± 14.72 years. Moreover, the mean value of BLLs among the participants was 7.92 ± 3.44 μg/dL. Correlation between BLL and systolic and diastolic blood pressure was not significant. The effects of lead on systolic and diastolic blood pressure after stepwise regression were B = -0.327 [confidence interval (CI) 95%: -0.877 to 0.223] and B = -0.094 (CI 95%: -0.495 to 0.307), respectively.

CONCLUSION

This study revealed that BLLs in battery firm workers to be normal. Additionally, BLLs were not significantly related with either systolic or diastolic blood pressure which might have been the result of normal BLLs.