Environmental injustice and childhood lead exposure in peri-urban (ger) areas of Darkhan and Erdenet, Mongolia

United States house dust Pb concentrations are influenced by soil, paint, and house age: insights from a national survey

BACKGROUND

Lead (Pb) in house dust contributes significantly to blood lead levels (BLLs) in children which may result in dire health consequences. Assessment of house dust Pb in the United States, relationships with Pb in soil and paint, and residential factors influencing Pb concentrations are essential to probing drivers of house dust Pb exposure.

OBJECTIVE

Pb concentrations in vacuum-collected house dust are characterized across 346 homes participating in the American Health Homes Survey II (AHHS II), a US survey (2018-2019) evaluating residential Pb hazards. Connections between house dust Pb and soil Pb, paint Pb, and other residential factors are evaluated, and dust Pb concentration data are compared to paired loading data to understand Pb hazard standard implications.

RESULTS

Mean and median vacuum dust Pb concentrations were 124 µg Pb g-1 and 34 µg Pb g-1, respectively. Vacuum-collected dust concentrations and dust wipe Pb loading rates were significantly correlated within homes (α < 0.001; r ≥ 0.4). At least one wipe sample exceeded current house dust Pb loading hazard standards (10 µg ft-2 or 100 µg Pb ft-2 for floors and windowsills, respectively) in 75 of 346 homes (22%). House dust Pb concentrations were correlated with soil Pb (r = 0.64) and Pb paint (r = 0.57). Soil Pb and paint Pb were also correlated (r = 0.6).

IMPACT

The AHHS II provides a window into the current state of Pb in and around residences. We evaluated the relationship between house dust Pb concentrations and two common residential Pb sources: soil and Pb-based paint. Here, we identify relationships between Pb concentrations from vacuum-collected dust and paired Pb wipe loading data, enabling dust Pb concentrations to be evaluated in the context of hazard standards. This relationship, along with direct ties to Pb in soil and interior/exterior paint, provides a comprehensive assessment of dust Pb for US homes, crucial for formulating effective strategies to mitigate Pb exposure risks in households.

Assessment of Air Pollution in Ulaanbaatar Using the Moss Bag Technique

Active moss biomonitoring, the so-called moss bag technique, widely applied in many countries, for the first time, was applied to assess the air quality in Ulaanbaatar (Mongolia). Moss bags with Sphagnum girgensohnii Russow were exposed in triplicate in three different periods: December-February, March-May, and December-May at 13 governmental air quality monitoring stations located in the vicinity of thermal power plants and residential areas. The plant tissue content of Al, Ba, Co, Cd, Cr, Cu, Fe, Mn, P, Pb, Sr, S, V, As, and Zn was determined using inductively coupled plasma-optical emission spectrometry, and a direct mercury analyzer was used to determine the Hg content. The samples in residential areas and near thermal power plants that were exposed for 3 months in winter and for 6 months (winter to spring) were characterized by the highest accumulation of the elements. In the moss bags exposed during spring, maximum accumulation of the determined elements was noted in residential areas and near main roads. Regardless of the exposure time and duration, the highest accumulation of Al, Fe, and V was determined at Dambadarjaa air quality station located near a highway and of Hg near the Amgalan power plant. Significant differences in element accumulation between seasons were observed, thus, the accumulation of Al, Ba, As, Co, Cr, Fe, Pb, V, and Zn was higher in spring, while P and S had higher content in the moss samples exposed during winter. The accumulation of elements over the 6-month exposure period was 1.1-6.7 times higher than that of the 3-month periods. Thus, the 6-month exposure can be considered a reliable deployment period as it ensures an adequate signal in terms of enrichment of pollutants. Factor analysis was applied to highlight the association of elements and to link them with possible sources of emission. Three factors were determined, the first one included Al, As, Ba, Co, Cr, Fe, Mn, Pb, Sr, and V and was identified as a geogenic-anthropogenic, the second (Cu, P, and S) and third (Cd and Zn) factors suggested anthropogenic origin. The Relative accumulation factor and enrichment factor were calculated to evaluate the level of air pollution and possible element sources. Considerable contributors to air pollution were Zn, Fe, As, V, Cr, and Al, which may originate from airborne soil particles of crustal matter or transport, as well as coal combustion for heating and cooking.

Lead Exposure Can Affect Early Childhood Development and Could Be Aggravated by Stunted Growth: Perspectives from Mexico

BACKGROUND

Lead can affect early childhood development (ECD) differentially due to nutritional deficiencies that lead to stunted growth, defined as being at least two standard deviations below the average height-for-age. These deficiencies are more frequent among children living in rural locations or with lower socioeconomic status (SES); however, studies at a population level are scarce worldwide. Early childhood development plays a crucial role in influencing a child's health and wellbeing throughout life. Therefore, the aim of this study was to analyze how stunted growth can modify the association between lead exposure and ECD in children from disadvantaged communities.

METHODS

Data were analyzed from the 2018 National Health and Nutrition Survey in localities with fewer than 100,000 inhabitants in Mexico (ENSANUT-100K). Capillary blood lead (BPb) levels were measured using a LeadCare II device and dichotomized as detectable (cutoff point ≥ 3.3 µg/dL) and non-detectable. As a measure of ECD, language development was assessed in n = 1394 children, representing 2,415,000 children aged 12-59 months. To assess the association between lead exposure and language z-scores, a linear model was generated adjusted by age, sex, stunted growth, maternal education, socioeconomic status, area, region (north, center, south), and family care characteristics; afterwards, the model was stratified by stunted growth.

RESULTS

Fifty percent of children had detectable BPb and 15.3% had stunted growth. BPb showed a marginal inverse association with language z-scores (β: -0.08, 95% CI: -0.53, 0.36). Children with detectable BPb and stunted growth had significantly lower language z-scores (β: -0.40, 95% CI: -0.71, -0.10) than those without stunted growth (β: -0.15, 95% CI: -0.36, 0.06).

CONCLUSIONS

Children with stunted growth are more vulnerable to the adverse effects of lead exposure. These results add to previous research calling for action to reduce lead exposure, particularly in children with chronic undernutrition.

Blood lead levels and lead toxicity in children aged 1-5 years of Cinangka Village, Bogor Regency

Lead is one of ten hazardous chemicals of public health concern and is used in more than 900 occupations, including the battery, smelting, and mining industries. Lead toxicity accounts for 1.5% (900,000) of deaths annually in the world. In Indonesia, reports of high Blood Lead Level (BLL) were associated with residency in Used Lead Acid Battery (ULAB) recycling sites. The present study aims to investigate the BLL and the evidence of lead toxicity of children living in an ULAB recycling site in Bogor Regency, Indonesia. A cross-sectional study involving 128 children aged 1–5 years was conducted in September-October 2019. The socio-economic factors, BLL, nutritional status, and hematological parameters, were evaluated. Data were analyzed by univariate and bivariate using the Chi-Square test. Socio-economic factors revealed only 2.3% children have pica and 10.9% children have hand-to-mouth habits. Majority of parents had low income, education, and have stayed in the village for years. Analysis on BLL revealed that 69.5% children had BLL of >10 μg/dL, 25% had abnormal BMI, 23.4% had underweight, 53.9% had stunting, 33.6% had anemia, and 22.6% had basophilic stippling. The average BLL and hemoglobin levels of respondents were 17.03 μg/dL and 11.48 g/dL, respectively. Bivariate analysis revealed that children with high BLL had double risk of having underweight and protected from stunting. Analysis on the association between BLL and BMI for age revealed a higher risk to have abnormal BMI. The high BLL also had 1.017 times risk of developing anemia, and almost doubled risk of having basophilic stippling, although they were not statistically significant. In conclusion, the high BLL of children living in the ULAB recycling indicates that lead exposure as well as lead toxicity are still occurring in Cinangka Village, and alerts to the need for a systematic action to mitigate the exposure.

Blood lead levels mediate the relationship between social adversity and child externalizing behavior

BACKGROUND/AIMS

The association between social adversity and externalizing behavioral problems in children is well-documented. What is much less researched are biological mechanisms that may mediate such relationships. This study examines the hypothesis that low blood lead mediates the relationship between social adversity and child externalizing behavior problems.

METHODS

In this cross-sectional study, participants were 131 children aged 11-12 years (mean = 11.90) from Philadelphia, US. A venous fasting blood sample was taken and analyzed for blood lead levels. A social adversity index was calculated based on 10 total indicators derived from a psychosocial interview of the parent and official neighborhood data, while child behavior outcomes (internalizing and externalizing behavior) were assessed using both parent-report and child self-report.

RESULTS

The mean blood lead level was 2.20 μg/dL. Both relatively higher blood lead levels and higher social adversity scores were associated with higher levels of parent-reported and child self-reported externalizing behaviors. Additionally, blood lead mediated the relationship between social adversity and child-reported externalizing behavior (Indirect effect: B = 0.03, 95% CI: 0.004, 0.09) and partially mediated the relationship between social adversity and parent-reported externalizing behavior (Indirect Effect: B = 0.03, 95% CI: 0.01, 0.07).

CONCLUSION

To our knowledge, this study is the first to suggest that blood lead levels play a mediating role in the relationship between externalizing behavior problems and social adversity. Findings have potentially important implications for public health and environmental regulation as well as understanding biological mechanisms that link social inequality with health outcomes, especially in youth from low-income, urban areas.

Environmental health survey for children residing near mining areas in South Gobi, Mongolia

Background

We evaluated the level and factors of heavy metal exposure to children residing in the Togttsetsii, Khanbogd, and Bayandalai soums of South Gobi province, Mongolia.

Methods

A total of 118 children aged 9–12 years were surveyed, and the level of heavy metal exposure in their bodies was investigated. Exposure was investigated by measuring concentrations of heavy metals such as cadmium, lead, and mercury in the blood; mercury concentration in the hair; and total arsenic in the urine.

Results

Blood cadmium concentration had geometric averages of 0.16 µg/L in the children from Bayandalai, 0.15 µg/L Tsogttsetsii, and 0.16 µg/L Khanbogd. Blood lead concentration showed a relatively higher geometric average of 7.42 µg/dL in the children from Bayandalai compared to 4.78 µg/dL and 5.15 µg/dL in those from Tsogttsetsii and Khanbogd, respectively. While blood mercury concentration was the highest in the children from Bayandalai, with a value of 0.38 µg/L, those from Tsogttsetsii and Khanbogd had similar concentrations of 0.29 µg/L and 0.29 µg/L, respectively. Hair mercury concentration was the highest in the children from Bayandalai, with a value of 78 µg/g, a particularly significant difference, with a concentration of 0.50 µg/g in those from Khanbogd. Urine arsenic concentration was the highest in the children from Khanbogd, with a value of 36.93 µg/L; it was 26.11 µg/L in those from Bayandalai and 23.89 µg/L in those from Tsogttsetsii.

Conclusions

The high blood lead concentration of children in Bayandalai was judged to be due to other factors in addition to mine exposure; the reason why blood and hair mercury concentration was higher in children from Bayandalai may have been due to exposure to many small-scale gold mines in the area. In the case of Khanbogd, it was estimated that the high arsenic level in urine was caused by the effect of mines.