Mapping Blood Lead Levels in China during 1980-2040 with Machine Learning.

Lead poisoning is globally concerning, yet limited testing hinders effective interventions in most countries. We aimed to create annual maps of county-specific blood lead levels in China from 1980 to 2040 using a machine learning model. Blood lead data from China were sourced from 1180 surveys published between 1980 and 2022. Additionally, regional statistical figures for 15 natural and socioeconomic variables were obtained or estimated as predictors. A machine learning model, using the random forest algorithm and 2973 generated samples, was created to predict county-specific blood lead levels in China from 1980 to 2040. Geometric mean blood lead levels in children (i.e., age 14 and under) decreased significantly from 104.4 µg/L in 1993 to an anticipated 40.3 µg/L by 2040. The number exceeding 100 µg/L declined dramatically, yet South Central China remains a hotspot. Lead exposure is similar among different groups, but overall adults and adolescents (i.e., age over 14), females, and rural residents exhibit slightly lower exposure compared to that of children, males, and urban residents, respectively. Our predictions indicated that despite the general reduction, one-fourth of Chinese counties rebounded during 2015-2020. This slower decline might be due to emerging lead sources like smelting and coal combustion; however, the primary factor driving the decline should be the reduction of a persistent source, legacy gasoline-derived lead. Our approach innovatively maps lead exposure without comprehensive surveys.

Peppered with lead: An environmental forensics approach to identify the source of rising blood lead levels.

Despite the phase-out of lead-based products, lead contamination can still present a contemporary risk to public health. In situations where elevated blood lead cannot be attributed to common sources, detailed environmental investigation is needed to identify more elusive sources and manage harmful exposure pathways. We apply a forensics approach to assess common and elusive sources of lead in the home environment of two individuals with fluctuating blood lead levels in Sydney, Australia. Using multiple analytical lines of evidence (portable X-Ray Fluorescence spectrometry (pXRF), inductively coupled-plasma mass spectrometry (ICP-MS), lead isotopic compositional analysis (PbIC) and haematological assessment) a pewter pepper grinder containing lead (>6000 mg/kg; 70% bioavailable) was identified as a potential source. After removing the pepper grinder from the home, the couple's blood lead decreased to below the Australian intervention level of 5 µg/dL within a year (Person A: from 12.5 µg/dL in August 2020 to 4.4 µg/dL in March 2022; and Person B: 15.4 µg/dL in August 2020 to 2.1 µg/dL in July 2021). This case study demonstrates how environmental science investigations can play a crucial role in supporting people to take evidence-based action to improve their health.

Unraveling the interaction between lead and calcium in occupationally exposed males: an exploratory observation study.

OBJECTIVE: The systemic illnesses associated with chronic lead exposure are partially explained by the interaction between lead and calcium metabolism. Lead exposure is posited to alter calcium levels either by altering calcium homeostasis markers or altering bone remodeling. The present study investigated the interaction between blood lead levels and calcium homeostasis markers and bone remodeling markers among lead-smelting plant workers. METHOD: Adult male workers employed at the lead-smelting plant were clinically investigated as part of their regular occupational health assessment program. Additionally, control participants without occupational lead exposure, employed in administrative and white-collar jobs were invited to participate in the study. Sociodemographic and occupational details were collected by pre-standardized semi-structured questionnaires from all consenting participants, followed by clinical examination and blood collection. Blood lead levels were estimated using microwave-assisted acid digestion and the inductively coupled plasma mass spectrometry technique. Serum calcium and total protein and alkaline phosphatase levels were estimated as per standard biochemical techniques. 25-hydroxy vitamin-D3, calcitriol, and osteocalcin were estimated using the enzyme-linked immunosorbent assay. In addition to comparative analysis for comparing the two groups, independent linear regression models were explored to investigate the associations between serum calcium and blood lead and osteocalcin levels. RESULT: A total of 189 lead-exposed men employed at the lead-smelting plant and 25 male control participants consented to participate. The two groups were similar in age, diet, and body mass index. Occupationally exposed individuals exhibited significantly lower serum calcium and higher bone remodeling markers (osteocalcin and alkaline phosphatase) as compared to controls. However, the serum 25-hydroxy vitamin-D3 and calcitriol levels were not significantly different between the two groups. Lastly, the serum lead and osteocalcin were weakly but significantly associated with serum calcium levels after controlling for variations in total protein, diet, 25-hydroxy vitamin-D3, calcitriol, and alkaline phosphatase in the study participants. CONCLUSION: Current observations reinforce the adverse role of lead exposure on calcium metabolism. Although lead exposure is posited to affect calcium metabolism by multiple pathways, current study observations favor the bone remodeling pathway. The observations recommend periodic screening for calcium and bone health among lead-exposed adults.

A new approach to a legacy concern: Evaluating machine-learned Bayesian networks to predict childhood lead exposure risk from community water systems.

Lead in drinking water continues to put children at risk of irreversible neurological impairment. Understanding drinking water system characteristics that influence blood lead levels is needed to prevent ongoing exposures. This study sought to assess the relationship between children's blood lead levels and drinking water system characteristics using machine-learned Bayesian networks. Blood lead records from 2003 to 2017 for 40,742 children in Wake County, North Carolina were matched with the characteristics of 178 community water systems and sociodemographic characteristics of each child's neighborhood. Bayesian networks were machine-learned to evaluate the drinking water variables associated with blood lead levels ≥2 µg/dL and ≥5 µg/dL. The model was used to predict geographic areas and water utilities with increased lead exposure risk. Drinking water characteristics were not significantly associated with children's blood lead levels ≥5 µg/dL but were important predictors of blood lead levels ≥2 µg/dL. Whether 10% of water samples exceeded 2 ppb of lead in the most recent year prior to the blood test was the most important water system predictor and increased the risk of blood lead levels ≥2 µg/dL by 42%. The model achieved an area under the receiver operating characteristic curve of 0.792 (±0.8%) during ten-fold cross validation, indicating good predictive performance. Water system characteristics may thus be used to predict areas that are at risk of higher blood lead levels. Current drinking water regulatory thresholds for lead may be insufficient to detect the levels in drinking water associated with children's blood lead levels.

Early childhood lead exposure and adolescent heart rate variability: A longitudinal cohort study.

Lead is a known neurotoxicant with many detrimental health effects, including neurocognitive deficits and cardiovascular and metabolic disorders. However, few studies have tested the association between lead exposure and the physiological stress response, which in and of itself may act as a precursor to and/or underlying mechanism of detrimental health outcomes. The purpose of this study was to examine the influence of early childhood and early adolescent low-level lead exposure on early adolescent heart rate variability, a widely-used measure of physiological stress. Participants were 408 children from Jintan, China for whom blood lead levels were measured between 3 and 5 years (early childhood) and again at 12 years (early adolescence). Heart rate variability was assessed at 12 years while participants underwent an induced stress task utilizing the ratio of low to high frequency (LF/HF) ECG measures. Mean blood lead levels in the cohort were 6.63 mcg/dl and 3.10 mcg/dl at 3-5 years and 12 years, respectively. Blood lead levels at 3-5 years of age (ß 0.06, p = 0.027), but not at age 12 (ß -0.05, p = 0.465), were significantly associated with LF/HF measures while controlling for multiple sociodemographic variables, potentially reflecting a dysregulated stress response with a shift towards sympathetic dominance. These findings suggest that early childhood lead exposure may have a detrimental influence on early adolescent autonomic responses to acute stress, which holds implications for cardiovascular health and overall growth and development.

Factors associated with blood lead levels in children in Shenyang, China: a cross-sectional study.

BACKGROUND: Although blood lead levels (BLLs) in children are gradually decreasing, low-concentration lead exposure can still exert adverse effects. We studied the factors that affect BLLs in children in Shenyang, China. METHODS: We conducted a cross-sectional study by administering structured questionnaires on family demographics and food intake. The concentrations of lead in venous blood were determined by graphite furnace atomic absorption spectrometry. RESULTS: A total of 273 children aged 1-6 years were enrolled. The geometric mean (geometric standard deviation) of BLLs was 24.94 (12.70) µg/L in boys and 23.75 (11.34) µg/L in girls. The prevalence of BLLs of ≥35 µg/L was 22.7% and was mainly observed in children aged under 3 years. Often hand washing before meals was protective against BLLs ≥20 µg/L (adjusted OR: 0.427, 95%CI: 0.238-0.767, p = 0.004). Consumption of puffed grains and eggs had an adjusted OR (95%CI) for BLLs ≥20 µg/L of 1.714 (1.012-2.901) (p = 0.045) and 1.787 (1.000-3.192) (p = 0.050), respectively. CONCLUSIONS: BLLs of children in Shenyang are still higher than in developed countries. Consumption of puffed grains and eggs is associated with higher BLLs. Often hand washing before meals may be protective against high BLLs.

Occupational lead exposure is an independent modulator of hypertension and poor pulmonary function: A cross-sectional comparative study in lead-acid battery recycling workers.

Blood lead level (BLL) is the primary biomarker for lead-exposure monitoring in occupationally exposed workers. We evaluated occupational lead-exposure (OE) impact on cardiopulmonary functions in lead-acid battery recycling unit workers. Seventy-six OE cases and 30 control subjects were enrolled for questionnaire-based socio-demographic, dietary, tobacco usage, and medical history data. Anthropometric measurements, systolic and diastolic blood pressure (SBP and DBP), and pulmonary function tests were performed. Venous blood was collected for BLL, hematological analysis, and biochemical analysis. OE caused a significant increase in BLL, SBP, DBP, and small airways obstruction in lung function tests. It also impaired platelet indices, affected renal and liver biochemical measurements, and promoted oxidative stress and DNA damage. Multilinear regression analysis suggested that BLL affected SBP (ß = 0.314, p = .034) and increased small airways obstruction (FEV1/FVC, ß = -0.37, p = .05; FEV25-75%, ß = -0.351, p = .016). Higher BLL appears to be an independent modulator of hypertension and poor pulmonary function upon occupational lead exposure in lead-acid battery recyclers.

Association of blood lead levels with preeclampsia: A cohort study in China.

BACKGROUND: Preeclampsia is the main cause of maternal and perinatal death, especially in developing countries. Multiple studies suggest that blood lead levels in pregnancy are a risk factor for preeclampsia, even with low levels of blood lead. But less knows the dose-effect relationship of preeclampsia in low blood lead levels. OBJECTIVES: This study aims to assess the association between blood lead levels and preeclampsia and to explore its dose-effect relationship between low blood lead levels and preeclampsia. METHODS: The retrospective cohort study was consecutively conducted in a comprehensive tertiary hospital in Foshan city of Guangdong Province, China, from August 1, 2019, to November 30, 2019. Blood lead levels were measured in maternal whole blood in 12-27 (+6) weeks of pregnancy, using atomic absorption spectrometer. Preeclampsia diagnosis was ascertained from the electronic medical records system. The risk of preeclampsia was estimated by multivariable logical regression analysis, and a two-stage linear regression model was established to find out the dose-effect. RESULTS: A total of 2174 people were included in this study, and 59 (2.7%) women developed preeclampsia. The dose-effect analysis revealed a non-linear association between blood lead levels and the risk of preeclampsia, with a cut-off point at 4.2 µg/dl. When blood lead levels were over 4.2 µg/dl, the risk of preeclampsia increased significantly with an increase in blood lead levels (OR = 2.05, 95%CI: 1.50, 2.81). In the multivariate regression models, per 1 µg/dl increment in blood lead levels was associated with 43% higher risk of developing preeclampsia (OR = 1.43,95%CI:1.17,1.74). Moreover, the association between blood lead levels and preeclampsia was stable in different subgroups. CONCLUSIONS: Low levels of lead exposure had a dose-effect relationship of preeclampsia, with a cut-off point at 4.2 µg/dl. Blood lead levels had a non-linear association with preeclampsia. When the blood lead levels were higher than 4.2 µg/dl, the risk of preeclampsia increases by 105% for every 1 µg/dl increase in blood lead levels.

Exploring persistent racial/ethnic disparities in lead exposure among American children aged 1-5 years: results from NHANES 1999-2016.

OBJECTIVE: The aim of this study was to determine whether long-standing racial disparities in lead exposure still exists for children age 1-5 years old. We examined if blood lead levels were higher among non-Hispanic Black children and others compared to non-Hispanic White children. METHODS: Data from the National Health and Nutrition Examination Survey (NHANES) from 1999-2016 were used. Geometric mean blood lead levels (BLLs) were compared by race/ethnicity using log-transformed simple linear regression. Associations between race and elevated BLL were assessed using weighted Chi-square tests. Log-transformed multiple weighted linear regression was used to assess what factors affected BLLs. RESULTS: A total of 6772 children were included in this study. In 1999-2000, the geometric mean BLL for non-Hispanic Black children was 3.08 µg/dL, compared to 2.03 µg/dL for non-Hispanic White children (p = 0.01). The difference in geometric mean BLL between non-Hispanic Black children and non-Hispanic White children continued to be statistically significant in later years (all p < 0.05) until 2015-2016 (0.89 µg/dL vs 0.74 µg/dL, p = 0.17). Log-transformed linear regression showed that being non-Hispanic Black and having low family income were independently associated with higher BLL. CONCLUSION: Although lead exposure in the general population continued to decline for all racial/ethnic groups, non-Hispanic Black children still had higher BLL than non-Hispanic White children. In more recent years, the racial/ethnic gap was lesser but persisted. Racial/ethnic disparity in childhood BLL could be partially explained by socio-economic factors.

Blood lead levels and their associated risk factors in Chinese adults from 1980 to 2018.

In China, studies on lead exposure to grownup are scarce compared to children, although relevant disease burdens for adults are much severe than that in developed countries. The present study evaluated blood lead levels (BLLs) in Chinese adults by data mining using Monte Carlo simulation. A total of 115 scientific studies published between January 1980 and March 2021 reflecting 45,514 Chinese adults were included in the study. After a continuous increase in Chinese adult BLLs from 1980-1983 (GM 74.84 µg/L) to 1994-1996 (GM 92.27 µg/L), BLLs began to decline from 2000--2002 (GM 80.32 µg/L) to 2016-2018 (GM 21.57 µg/L). This decline implied that the lead phase-out policy in gasoline was effective over the past two decades. The study indicated that North, South, and Southwest China were still relatively high compared to other regions in the past decade. Statistical analysis showed that BLLs of males (GM 68.45 µg/L) were higher than females (GM 56.51 µg/L), smokers (GM 80.96 µg/L) higher than nonsmokers (GM 58.95 µg/L), and populations over 40 (GM 40.43 µg/L) higher than younger populations (GM 40.37 µg/L). The significantly positive correlation between the concentrations of PM2.5 and topsoil lead and BLLs in Chinese adults indicated that air and soil pollution affect adult BLLs. Taken together, our results showed that strict lead control strategies and regular bio-monitoring are needed to maintain low BLLs in the population.

Evaluation of blood lead among painters of buildings and cars.

Exposure to lead-based paints is a major threat to the health of painters. This study aimed to evaluate the blood concentration of lead (Pb) in painters of buildings and cars. The present study was a cross-sectional study in which a semi-structured questionnaire was used to collect the socio-demographic information. Lead concentration in blood samples was determined using the atomic absorption spectrometry method. A total of 32 male painters were selected based on inclusion criteria. The mean blood lead level (BLL) in the painters was 8.1 ± 4.93 µg/dL. Pb levels in car and building painters were 9.42 ± 5.5 µg/dL and 6.7 ± 1.85 µg/dL, respectively. Pb concentration in none of the blood samples was more than 30 µg/dL. The prevalence of BLL ≥ 5 µg/dL and BLL ≥ 10 µg/dL was 97% and 19%, respectively. According to the findings, the rate of BLL among car painters was higher than building painters. Considering the presence of Pb in all blood samples, it seems necessary to increase the awareness of painters about the adverse effects of lead exposure even in low concentrations. However, the sample size in this study was small and more investigations are required in this regard.

Challenges in diagnosing lead poisoning: A review of occupationally and nonoccupationally exposed cases reported in India.

Lead is a nonessential metal which enters the body through various means and is considered as one of the most common health toxins. Several cases of lead poisoning are reported as a result of inhalation or ingestion of lead in employees working as painters, smelters, electric accumulator manufacturers, compositors, auto mechanics, and miners. In addition to occupational lead exposure, several cases of lead poisoning are reported in the general population through various sources and pathways. Innumerable signs and symptoms of lead poisoning observed are subtle and depend on the extent and duration of exposure. The objective of this review article is to discuss occupationally and nonoccupationally exposed lead poisoning cases reported in India and the associated symptoms, mode of therapy, and environmental intervention used in managing these cases. Lead poisoning cases cannot be identified at an early stage as the symptoms are very general and mimic that of other disorders, and patients might receive only symptomatic treatment. Knowledge about the various symptoms and potential sources is of utmost importance. Medical practitioners when confronted with patients experiencing signs and symptoms as discussed in this article can speculate the possibility of lead poisoning, which could lead to early diagnosis and its management.

Influence of task-based airborne lead exposures on blood lead levels: a case study of informal automobile repair artisans in Nakuru town, Kenya.

Lead poisoning is an emerging worldwide public health concern, especially in the developing countries. Occupational tasks such as spray painting and welding in informal automobile repair enterprises present risks of exposures to lead generally through inhalation and ingestion. The artisans therefore risk high blood lead (BPb) levels, which is critical to chronic adverse health effects of lead. The study aimed at assessing the influence of occupational tasks on personal airborne lead exposures and to evaluate the association between these exposures with blood lead (BPb) levels among the artisans. A cross-sectional study was conducted in ten informal automobile repair workshops. Task-specific personal inhalable air samples and blood samples were collected concurrently for 20 participants performing five distinct occupational tasks. Lead levels were analysed using inductively coupled plasma atomic emission spectroscopy and data analysed by analysis of variance, simple and multiple linear regressions. The results indicated significant differences in airborne lead (PbA) exposure levels in different occupational tasks (p = 0.000). Lead-acid battery repairs recorded mean PbA exposure level of [76.11 ± (10.81 SE) µg/m3] exceeding the WHO 50 µg/m3 airborne lead permissible exposure limit. The average (PbA) exposure level was 22.55 ± (5.05 SE) µg/m3, while the mean (BPb) level was 25.08 ± (3.48 SE) µg/dl. A significant positive correlation between task-based airborne lead with blood lead levels was observed (r = 0.68, p = 0.001). In conclusion, the occupational tasks influenced personal airborne lead exposure levels, which in turn was an important predictor of blood lead levels. The study recommends lead exposure assessments, medical screening and intervention measures to minimize the risk and consequences of occupational exposures to lead among the study population.

Blood Lead Levels in Occupationally Exposed Workers Involved in Battery Factories of Delhi-NCR Region: Effect on Vitamin D and Calcium Metabolism.

Workers involved in battery manufacturing or recycling factories are occupationally exposed to high concentrations of lead. In humans, lead can cause a wide range of biological effects depending upon the level and duration of exposure. The purpose of this study was to find out the blood lead levels (BLL) in occupationally exposed workers involved in battery industry in Delhi NCR region and to study whether lead affected the vitamin D (vit D) and calcium metabolism. For this study 100 occupationally lead-exposed battery workers (LEBW) and 100 non-lead exposed controls (NLEC) were recruited. BLL were measured using inductively coupled plasma optical emission spectrometer (ICP-OES) technique while ELISA was performed to quantify the serum vit D levels in the study subjects. Routine biochemical parameters were measured by chemistry autoanalyzers. Statistical analysis was done using appropriate statistical tools. Results showed that BLL were significantly higher in LEBW as compared to NLEC (p < 0.0001). Serum vitamin D, calcium and phosphorus levels were significantly decreased in battery workers as compared to controls (p < 0.005). Spearman's rank correlation analysis showed significant negative correlation of BLL with serum Vitamin D and calcium levels. Significant positive correlation was observed between BLL and duration of lead exposure. Weak negative correlation was also observed between BLL and vit D even after adjusting for smoking status. In conclusion, this study demonstrated that higher BLL significantly alters the vit D and calcium metabolism.

Cost-benefit of point-of-use devices for lead reduction.

BACKGROUND: Lead exposure represents a significant human health concern that often occurs with little warning to the consumer. Water lead levels can be mitigated by point-of-use (POU) devices such as reverse osmosis, distillation, or activated carbon with lead reduction media. OBJECTIVES: This study assessed a partial cost-benefit of residential installation of POU devices to reduce lead concentrations in drinking water and examined the economic impact at the community level based on exposures reported in Flint, Michigan. METHODS: We calculated the individual consumer breakeven point for each lead abatement option by subtracting the lifetime cost of device installation and maintenance from the lifetime cost of lead exposure through its impact on intelligence (IQ) and lifetime earnings. This approach was then extrapolated to the community level based on reported lead exposures in Flint, Michigan. RESULTS: Based on operating POU device costs, lead absorption from water, and economic losses associated with reduced IQ, initial water lead levels associated with consumer breakeven points for reverse osmosis (7.31 µg/L), activated carbon (3.73 µg/L), and distillation (12.0 µg/L) were calculated. For example, an individual consuming water with 25 µg/L of lead, similar to the 90th percentile of concentrations measured in Flint, Michigan, would have an expected blood lead level of 1.25 µg/dL, a corresponding loss of 0.641 IQ points, and a lifetime economic earnings loss of $14,284. Over 70 years of continued use, activated carbon with lead reduction media is the least expensive device to maintain and operate as compared to reverse osmosis and distillation. CONCLUSIONS: Infrastructure failures related to drinking water are unpredictable and exposure to contaminates can have significant economic ramifications. POU devices represent a cost-effective option to reduce the impact of lead exposure, particularly when water lead concentrations exceed regulated levels.

The CDC blood lead reference value for children: time for a change.

The purpose of this article is to consider alternate uses of the blood lead reference value for children. There are two possible approaches. Historically the reference value has been used to guide clinical and public interventions for individual children. As the distribution of blood lead levels in the population has been lowered over time, the blood lead level at which interventions are recommended has also been reduced. The use of a reference value of 3.5 µg/dL, based on the 98 percentile of blood lead levels for children in 2011-2014 National Health and Nutrition Examination Survey is under review. For several reasons, adopting the new reference value to guide clinical and public health management puts practitioners in an untenable position. First, the changes in the brain caused by lead are significant and persistent. However, these adverse impacts are subtle and although clearly identified at the population level, not predictive for individual children. In addition, the recommended interventions have not been shown to reduce blood lead levels once they are elevated. Finally, clinical laboratory and office-based blood lead testing devices are not required to quantify blood lead levels < 4 µg/dL and in many cases cannot reliably test for low blood lead levels. Revising the reference value also will undoubtedly result in diversion of resources away from those population-based interventions which have demonstrated success. We argue for second approach, in the management of lead poisoning in the US from one of evaluation and management at the individual level to one of population based primary prevention. This would require a strategy directed at controlling or eliminating lead in children's environment before they are exposed. The reference value, as a benchmark, is essential to ensure that primary prevention efforts are successful.

Association of low-level blood lead with serum uric acid in U.S. adolescents: a cross-sectional study.

BACKGROUND: Uncertainty remains regarding the association between blood lead levels (BLL) and serum uric acid (SUA) with relatively low BLL exposure because of limited data in the adolescent population. We examined the association between BLL and SUA in U.S. adolescents. METHODS: In this cross-sectional study, 8303 adolescents aged 12-19 years from NHANES 1999-2006 were analyzed. BLL was Ln-transformed for analysis for the skewed distribution. Elevated SUA was defined as ≥5.5 mg/dL. Multivariate linear and multiple logistic regression analyses were performed to evaluate the association of BLL with SUA and elevated SUA. Moreover, a generalized additive model (GAM) and a fitted smoothing curve (penalized spline method) were conducted. RESULTS: The overall mean BLL was 1.3 µg/dL. Multivariate linear regression analyses showed that LnBLL was independently and positively correlated with SUA level (ß = 0.13, 95%CI: 0.09-0.17). Multiple logistic analyses showed that LnBLL was associated with a 24% increased prevalence of elevated SUA (OR = 1.24; 95% CI, 1.11-1.38). Analyses using restricted cubic spline confirmed that the associations of LnBLL with SUA and elevated SUA were linear. Subgroup analyses showed that stronger associations between LnBLL and SUA were detected in adolescents with lower levels of education and estimated glomerular filtration rate (eGFR) (all P for interaction < 0.05). CONCLUSIONS: BLL was independently and positively correlated with SUA level and elevated SUA among U.S. adolescents, particularly with lower levels of education and eGFR. The data suggest that there is no "safe" threshold level of exposure to lead.

The reference value of blood lead level among the general adult population of eastern Iran.

The aim of this study to the estimate the lead concentrations in the blood of the adult population in South Khorasan Province, evaluate factors related to high lead blood concentrations and establish lead reference values (RVs) in our study population. In cross-sectional study, 400 people who lived in the province of South Khorasan in 2017 were selected. Demographic information was collected and clinical examinations were performed. As the geometric means, blood lead concentration (BLC) was expressed, 10th, 50th, 90th, and 95th percentiles, and 95% confidence intervals (CI) of the 95th percentile. The upper limits rounded values of the 95% CI with the 95th percentile were applied to calculate RVs. Mean BLC was 6.02 ± 7.41 µg dL-1, median of BLC was 4.4 µg dL-1 (IQR: 2.9-6.5; range 0.9-54.7 µg dL-1). One hundred and twenty-five (31.2%) participants had BLCs between 5 and 10.0 µg dL-1, 40 (10.0%) between 10 and 20.0 µg dL-1, and 15 (3.8%%) over 20 µg dL-1. The RVs for BLC for men and women were 16 [95% CI: 10.13-15.96] µg dL-1 and 15 [95% CI: 9.81-14.45] µg dL-1, respectively. Higher BLCs were significantly associated with age, gender, hemoglobin, white blood cell count, and serum phosphorus concentration. This bio-monitoring study of BLCs in the general population of South Khorasan Province offers important demographic and lifestyle factors-stratified reference data. It is essential to continue efforts to reduce lead exposure.

Environmental and socioeconomic factors induced blood lead in children: an investigation from Kashmir, India.

Blood lead toxicity has been prominently related to vehicular emissions. The lead is a carcinogenic metal systematically damages bones and central nervous system. The present investigation is focused on likely impacts of environmental and socioeconomic factors on the concentration of blood lead levels in children. The findings of the study show that the highest blood lead levels were observed in the age group of 4-8 years (5.46 µg/dl) with mother's education having an inverse proportionality with the blood lead levels of children. Furthermore, children belonging to families with income (> 100,000) exhibited the highest blood lead levels (5.52 µg/dl) than the rest of the categories which was further advocated by lower blood lead levels in children residing in better residential conditions. High proximity of school to highway distance seemed to play a vital role in the concentration of lead in children while the traffic flow density was observed to have proportionality effect on the blood lead levels. From the study, it is concluded that 28% of the children in the sample population were having lead levels above the permissible limits as per Centre for Disease Control and Prevention. The study reflects the alarming toxicity of lead in children residing in a non-industrial region which further gives rise to concerns about the health of the children residing in industrialized regions of the world with high lead levels in the environment.

Lead toxicity with a new focus: Addressing low-level lead exposure in Canadian children.

Although acute and subacute lead toxicity requiring active treatment is rare in Canada, paediatricians need to be aware of new evidence linking lower lead levels to neurodevelopmental deficits. Health Canada has identified potential exposures occurring prenatally, in infancy and during early childhood from food and water, household dust, soil, and mouthing products that contain lead. Children with neurodevelopmental problems who live in older housing and newcomers to Canada may be at greater risk. Symptoms may be latent, subtle, and chronic. Blood assay, widely available clinically, does not confirm diagnosis unless lead exposure has been recent. Human biomonitoring data are available in the Canadian Health Measures Survey, and Health Canada has suggested that clinicians use these new reference ranges. Early detection and prevention of lead exposure are key public health objectives because effects of lead toxicity are chronic and treatment is complex.