Lead pollution-related health of children in China: Disparity, challenge, and policy

Lead seasonality: Affect children's blood lead levels and implication for lead exposure prevention

Lead seasonality attributed to the patterns of Pb variation in the natural environment should be considered in the Pb risk analysis and related to the seasonality evident in humans. In this study, we integrate the Xi'an soil and dust lead seasonality data (554 surface soil samples and 554 road dust samples in three seasons) to evaluate the seasonal lead burden on children and propose the implications for children's lead exposure prevention strategies considering the lead seasonality and the influences from urban land use and children's living environment. The results showed that most seasonal variation patterns of soil and dust Pb are observed in winter (cold season), which coincided with the observation of higher children's blood lead levels in winter, although the strong correlation coefficients between children's blood lead levels (BLLs) and soil/dust Pb are observed in summer. The combinations of meteorological factors and anthropogenic pollutant emission strongly determine the metal seasonal variations. Those arrays of evidence suggest that lead seasonality is multifactorial within the environment and humans. Land uses and living environments such as old residential areas, heavy traffic, and fewer green parks, etc. have a significant impact on the increase of children's BLLs. Lead exposure prevention is proposed by BLLs warning and effective measure of reduction ≤ 50 μm soil/dust size fraction in winter.

Routine paediatric lead screening questionnaires may not fully capture current risk factors

Elevated blood lead levels (BLLs) affect a third of the worldwide paediatric population. Current screening tools in the USA focus primarily on exposure to lead-based paint. We describe a case of elevated BLL in a US-born paediatric patient from contaminated turmeric purchased abroad. There has been increasing evidence that imported spices and products are sources of lead due to fewer regulations abroad. Current lead screening questionnaires need to be reconsidered, as they may not fully capture non-traditional risk factors associated with lead poisoning.

A more scientific blood lead reference value urgently needs to be updated in China: From a national and international insight

Although blood lead levels (BLLs) in children have significantly decreased compared to two decades ago, incidents of lead poisoning and elevated BLLs among children continue to occur frequently. This trend suggests that China's current hygienic regulations are not sufficiently effective in managing children's lead exposure. This study analyzed the revision processes of blood lead reference values (BLRVs) in children from various countries, the current BLLs and their changing trends in China, potential sources of lead pollution and exposure, the requirements for managing and protecting children's health, as well as the national measures and strategies for lead emission management and control. The study also explored the necessity and urgency of updating China's BLRVs in children. Based on the specific conditions in China, a proposed BLRV of 50 μg/L was deemed more reasonable and was suggested for implementation, with the potential to yield substantial economic benefits through improved IQ outcomes should the updated BLRV be adopted.

Advances in environmental pollutant detection techniques: Enhancing public health monitoring and risk assessment

Accurate detection and monitoring of environmental pollutants are of paramount importance for disease prevention and public health. In recent years, the ever-expanding human activities and industrial production have given rise to a sharp increase in the complexity and variety of these pollutants, which pose significant threats to human well - being. Environmental pollutants stem from multiple sources, such as heavy metals, persistent organic pollutants, inorganic non - metallic pollutants, emerging pollutants, and biological contaminants. Traditional detection technologies, though valuable for their sensitivity and accuracy, are constrained by complex sample preparation, poor selectivity, and the absence of standardized detection methods. On the other hand, emerging technologies, including nanotechnology, molecular detection methods, biosensors, Surface-Enhanced Raman Spectroscopy (SERS), multi-omics, and big data analysis, offer promising solutions for rapid and sensitive pollutant detection. The establishment of environmental monitoring networks and data - sharing platforms further enhances real - time pollutant monitoring and provides solid data support for public health initiatives. Nonetheless, challenges persist, including data integration, exposure assessment, and the development of cost-effective and portable detection solutions. Future progress in interdisciplinary approaches and technology integration will be crucial for advancing environmental pollutant detection and facilitating comprehensive disease prevention. This review systematically classifies environmental pollutants and showcases the latest advancements in detection technologies, offering critical insights for environmental monitoring and public health protection.

Children's health impact in a smelter site area in China: modeling approaches for the identification and ranking of the most relevant lead exposure routes

Elevated blood lead levels (BLLs) in children still represent a major public health problem worldwide. In China, children's lead (Pb) exposure assessment constitutes a priority issue for research, also due to the scarce availability of human biomonitoring data and limited detailed exposure assessments outside urban areas. This work aims to analyze children's health impact by exploiting exposure modeling approaches to identify the most relevant Pb sources and exposure routes for 0-7-year-old children in a historical Pb-Zn smelter site in Yunnan province (southwestern China), characterized by heavy environmental pollution conditions. For this purpose, two exposure modeling tools, the Integrated Exposure Uptake Bio-Kinetic and MERLIN-Expo, were applied, using measured Pb concentrations in environmental media and food items from a local field campaign as input data. Simulated BLLs, including probabilistic estimates, were obtained and verified against real biomonitoring data from the literature. Model results for the simulated exposure scenario indicate significantly high children's BLLs (>10 µg/dl), which reflect the elevated Pb concentrations measured in environmental matrices and are mostly in agreement with previous biomonitoring data from the region. Moreover, soil and dust ingestion resulted to be the dominant exposure pathway, contributing more than 70% to the overall Pb exposure in children in all investigated scenarios. This work showed how tools for internal exposure modeling can contribute to Pb exposure assessment as complementary tools to demanding and invasive biomonitoring studies and can help identify priority exposure routes for improving risk management.

Using machine learning to predict soil lead relative bioavailability

Although the relative bioavailability (RBA) can be applied to assess the effects of Pb on human health, there is no definition and no specific data of Pb-RBA to different soil sources and endpoints in vivo. In this study, we estimated the Pb-RBA from different soil sources and endpoints based on machine learning. The Pb-BAc and Pb-RBA in soils were found to be mostly in the range of 20-80 %, which is different from the USEPA Pb-RBA of 60 % in soils. The mean Pb-RBA for different biological endpoints in vivo predicted using the RF model were 49.94 ± 18.65 % for blood; 60.15 ± 26.62 %, kidney; 60.90 ± 21.51 %, liver; 50.70 ± 17.56 %, femur; and 62.89 ± 16.64 % as a combined measure. Pb-RBA of shooting range soils was 88.21 ± 16.92 % (mean), spiked/aged soils 77.11 ± 14.05 % and certified reference materials 73.70 ± 20.31 %; agricultural soil 68.28 ± 18.93 %, urban soil 64.36 ± 21.82 %, mining/smelting soils 53.99 ± 17.66 %, and industrial soils 47.71 ± 20.35 %. This study is first to define the Pb-RBA according to various soil sources and endpoints in vivo with the objective of providing more accurate Pb-RBA data for soil lead risk assessment.

Health effects of mixed metal exposure on accelerating aging among the elderly population

BACKGROUND

Human exposure to heavy metals occurs through multiple pathways in daily life. However, the effects of mixed heavy metal exposure on accelerated aging in the elderly U.S. population remains unclear. This study aims to investigate the association between heavy metal concentrations in blood and urine and the onset of accelerated aging.

METHODS

A total of 2530 individuals were included in the blood metals analysis and 716 individuals in the urine metals analysis in this study. GrimAge acceleration (AgeAccelGrim) was calculated as the residuals from regressing DNA methylation GrimAge on chronological age. Weighted multivariable logistic regression models were applied to analyze the relationship between metal exposure with AgeAccelGrim. Bayesian kernel machine regression (BKMR) was performed to estimate the effects of individual metals or metals mixtures and AgeAccelGrim.

RESULTS

We found that blood cadmium (Cd) concentration was positively associated with an increased risk of AgeAccelGrim in both females and males, with odds ratios (OR) of 5.73 (95 % confidence interval (95 % CI): 1.88-17.41, P trend = 0.008) and 14.25 (95 % CI: 4.88-41.62, P trend < 0.001), respectively. Moreover, these associations were more pronounced for urinary Cd compared to blood Cd. Blood lead (Pb) was also associated with a 3.52-fold (95 % CI: 1.21-10.24, P trend = 0.007) increase in AgeAccelGrim risk among males. BKMR confirmed the aforementioned findings, identifying Cd as the most significant contributor to accelerated aging.

CONCLUSIONS

Exposure to heavy metals, either individually or in mixture, was positively associated with accelerated biological aging. These associations were more pronounced in males.

Childhood lead exposure and sleep problems in adolescents: a longitudinal cohort study

PURPOSE

Childhood lead exposure is linked to poorer neurobehavioral function in adolescence, but the relationship between lead and adolescent sleep health remains inconsistent. This study aimed to investigate concurrent and longitudinal associations between lead exposure and multiple sleep health domains in adolescents.

METHODS

A total of 972 adolescents from China Jintan Child Cohort were included in analyses. The Blood lead levels (BLLs) were assessed in two Waves, at ages 3-5 years (mean 6.50 ± 2.76 μg/dL) and 11-13 years (mean 3.12 ± 1.17 μg/dL). Sleep problems at age 11-13 were parent-reported via the Child Sleep Health Questionnaire (CSHQ) and self-reported by adolescents using the Pittsburgh Sleep Quality Index (PSQI).

RESULTS

Both early and later BLLs were associated positively with parental reported sleep problems, including sleep onset delay, night waking, short duration, parasomnias, and disordered breathing. Sex-stratified analyzes showed that most adjusted associations between two-Wave BLLs and sleep outcomes (CSHQ and PSQI) remained statistically significant in males, with a minor increase in the magnitude of these associations. The association between Wave II BLLs and shorter self-reported sleep duration was only statistically significant in female adolescents. Compared to children with consistently low BLLs at both ages, those with persistently high BLLs at both ages had significantly shorter parental-reported sleep duration and worse sleep onset delay.

CONCLUSION

Findings suggest that both early and later childhood lead exposures link to more adolescent sleep problems, with recent BLLs showing stronger associations with poor adolescent sleep health reported by their parents.

Association of urinary and blood lead concentrations with all-cause mortality in US adults with chronic kidney disease: a prospective cohort study

Epidemiological evidence on the relationship between lead exposure and mortality in specific chronic kidney disease (CKD) populations is limited. We aimed to examine the relationship between urinary lead and blood lead concentrations and all-cause mortality in US patients with CKD. This cohort study included 2320 participants with CKD from the National Health and Nutrition Examination Survey (2005-2018), with follow-up until December 31, 2019. All-cause mortality was ascertained by matching US National Death Index records. Hazard ratios (HRs) and 95% confidence intervals (CI) for urinary lead and blood lead concentrations in relation to all-cause mortality were estimated using a weighted Cox regression model. During a median follow-up period of 79 months, a total of 625 participants with CKD succumbed to mortality. Compared to the lowest quartile, the highest quartile of urine and blood lead concentrations was associated with an increased risk of all-cause mortality, with HRs and corresponding 95% CIs of 1.77 (1.05-2.99) and 2.65 (1.38-5.10), respectively. Furthermore, each additional unit increase in urinary and blood lead concentrations was associated with HRs for all-cause mortality of 1.21 (95% CI 1.06-1.38) and 1.09 (95% CI 1.01-1.19), respectively. Kaplan-Meier survival curve analysis and restricted cubic regression spline curve analysis demonstrated significant positive associations between elevated blood lead levels, elevated urinary lead levels, and all-cause mortality risk (P < 0.05). A nonlinear concentration-response relationship was observed between blood lead level and all-cause mortality risk (PNonlinear < 0.05), with an inflection point at a concentration of 1.613 µg/dL. Subgroup analysis as well as sensitivity analysis yielded consistent findings. Our findings demonstrate that elevated levels of lead in urine and blood are associated with a significantly increased mortality risk among patients with CKD, underscoring the importance of reducing lead exposure to mitigate mortality risk in individuals at high risk for CKD.

Lead exposure in Chinese children: Urbanization lowers children's blood lead levels (BLLs)

Lead is a toxic metal that can pose a huge threat to children's health. China has experienced rapid urbanization since the reform in 1978; however, there has been no examination of the potential influence of this urbanization on children's blood lead levels (BLLs). This study is the initial investigation to explore the correlation between urbanization and BLLs in Chinese children. Five windows of time are considered: pre-2000, 2001-2005, 2006-2010, 2011-2015 and 2016-2021. The results show that urbanization affected lead distribution in urban soil and agricultural soil during the above periods, especially in northern China. The higher non-carcinogenic risk of lead for children is consistent with the lead pollution in soil (3 < Igeo ≤ 4). Urban children's BLLs are slightly higher than those of rural children in 2001-2010, but rural children's BLLs in 2011-2021 are higher than those of urban children during China's urbanization. The areas of rural decline and the areas of urban growth increased across all the window periods. However, the BLLs decrease in all rural and urban areas during all window periods, especially in urban areas. Children's BLLs have a significantly negative correlation with urban areas (p < 0.01). Therefore, China's urbanization has a significant effect on the decrease in children's BLLs. The significance of this study is to provide a fresh perspective and innovative strategy for policymaking in order to reduce children's BLLs and prevent lead exposure. This can be achieved by transforming their external living environment from a rural lifestyle to an urban one, while also ensuring access to well education and maintaining a balanced nutrient intake.

Content of Toxic Elements (Arsenic, Cadmium, Mercury, Lead) in Eggs from an Ethically Managed Laying Hen Farm

Domestic chicken farming has been promoted and spread in several Italian municipalities and worldwide as an aid to the self-consumption of domestically produced food. This study investigated the levels of four toxic elements (As, Cd, Hg, and Pb) in eggs from an ethical laying hen farm, comparing the element concentrations with those possibly present in supermarket eggs. A total of 201 eggs, 141 from the farm and produced by different hen genotypes, and 60 from the supermarket, were collected. The levels of the toxic elements were evaluated in the yolk, albumen, and eggshells of all eggs. The results show that the supermarket eggs' yolk and albumen were more contaminated with lead, compared to the rural eggs. Contrarily, the mean content of arsenic was higher in the albumen and eggshells of the rural eggs, compared to the supermarket eggs. The cadmium content was below the LOQ (0.005 mg/kg) in all samples. The mercury content was below or around the LOQ in all rural eggs. Overall, the supermarket egg albumens were significantly more contaminated than the rural ones. No significant differences were found in quality parameters for both types of eggs. The toxic element values that were detected were in line with other studies in the literature. However, despite the concentrations found not representing a risk to the consumers' health, the results of this study raise a potential food safety issue, and it would be desirable to set specific MRLs for eggs for consumers' protection.

Utilizing different types of biomass materials to modify steel slag for the preparation of composite materials used in the adsorption and solidification of Pb in solutions and soil

This study utilized discarded steel slag (SS) as raw material and prepared modified steel slag materials (SS-SBC, SS-NBC, SS-BHA) through modification with biomass materials such as straw biochar (SBC), nutshell biochar (NBC), and biochemical humic acid (BHA). These materials were then applied for the removal of Pb from both solution and soil. The physical and chemical properties of the materials were analyzed using characterization techniques such as SEM, EDS, XRD, and BET. The specific surface area of the modified materials increased from the original 3.8584 m2/g to 34.7133 m2/g, 181.7329 m2/g, and 7.7384 m2/g, respectively. The study then explored the influence of different adsorption conditions on the adsorption capacity of Pb in solution, determining the optimal conditions as follows: initial concentration of 200 mg/L, adsorbent mass of 0.04 g, temperature of 15 °C, and pH = 2. To further investigate the adsorption process, kinetic and isotherm models were established. The results indicated that the adsorption process for all three materials followed a pseudo-second-order kinetic model and Freundlich isotherm model, suggesting a multi-layer chemical adsorption. Thermodynamic analysis revealed that the adsorption process was an exothermic spontaneous reaction. Soil cultivation experiments were conducted to explore the effects of different material addition amounts and cultivation times on the passivation of Pb-polluted soil. Analysis of heavy metal forms in the soil revealed that the addition of modified materials reduced the acid-extractable form of Pb in the soil and increased the residual form, which is beneficial for reducing the migration of Pb in the soil. FT-IR and XPS analyses were employed to study the functional groups, element composition, and valence states before and after adsorption passivation of Pb by the three materials. The results confirmed that the adsorption mechanisms of SS-SBC, SS-NBC, and SS-BHA mainly involved electrostatic adsorption, ion and ligand exchange, and surface precipitation. This study not only provides a new material for adsorbing and immobilizing heavy metals in soil and water but also offers a new approach for the resource utilization of steel slag waste.

Prenatal Lead Exposure, Genetic Factors, and Cognitive Developmental Delay

Importance

Although the effects of lead (Pb) exposure on neurocognition in children have been confirmed, the individual associations of prenatal Pb exposure and its interaction with genetic factors on cognitive developmental delay (CDD) in children remain unclear.

Objective

To investigate the association of prenatal Pb exposure and its interaction with genetic factors with CDD risk.

Design, Setting, and Participants

Women in Wuhan, China, who had an expected delivery date between March 2014 and December 2017, were recruited for this prospective cohort study. Children were assessed for cognitive development at approximately 2 years of age (March 2016 to December 2019). Maternal venous blood, cord blood, and venous blood from children were collected in a longitudinal follow-up. Data analysis was performed from March 2022 to February 2023.

Exposure

Prenatal Pb exposure, and genetic risk for cognitive ability evaluated by polygenic risk score constructed with 58 genetic variations.

Main Outcomes and Measures

Cognitive developmental delay of children aged approximately 2 years was assessed using the Chinese revision of the Bayley Scale of Infant Development. A series of multivariable logistic regressions was estimated to determine associations between prenatal Pb exposure and CDD among children with various genetic backgrounds, adjusting for confounding variables.

Results

This analysis included 2361 eligible mother-child pairs (1240 boys [52.5%] and 1121 girls [47.5%]; mean [SD] ages of mothers and children, 28.9 [3.6] years and 24.8 [1.0] months, respectively), with 292 children (12.4%) having CDD. Higher maternal Pb levels were significantly associated with increased risk of CDD (highest vs lowest tertile: odds ratio, 1.55; 95% CI, 1.13-2.13), adjusting for demographic confounders. The association of CDD with maternal Pb levels was more evident among children with higher genetic risk (highest vs lowest tertile: odds ratio, 2.59; 95% CI, 1.48-4.55), adjusting for demographic confounders.

Conclusions and Relevance

In this cohort study, prenatal Pb exposure was associated with an increased risk of CDD in children, especially in those with a high genetic risk. These findings suggest that prenatal Pb exposure and genetic background may jointly contribute to an increased risk of CDD for children and indicate the possibility for an integrated strategy to assess CDD risk and improve children's cognitive ability.