Pb Exposure Levels Research Articles

Interplay and long-lasting effects of maternal low-level Pb, Hg, and Cd exposures on offspring cognition

Lead (Pb), mercury (Hg), and cadmium (Cd) are prevalent and persistent environmental contaminants, causing detrimental effects on millions of individuals worldwide. Our previous research demonstrated that early-life exposure to low-level Pb, Hg, and Cd mixtures may lead to cognitive impairments. However, the association and interaction among low levels of Pb, Hg, or Cd exposure remains unclear. In this study, a two-level full factorial design (5.481, 0.036, and 2.132 mg/L for Pb, Hg, and Cd respectively) was conducted to assess the interplay among maternal Pb, Hg, and Cd exposure on offspring cognition. Following exposure during pregnancy and lactation, a competitive absorption among Pb, Hg, and Cd was observed. Maternal exposure to each metal alone resulted in higher blood and brain concentrations of Pb, Hg, and Cd in offspring compared to co-exposure at equivalent levels. However, behavioral experiments conducted in the Morris water maze and novel object recognition test revealed maternal Pb, Hg, and Cd exposure synergistically impaired offspring's spatial cognition and recognition memory. Importantly, this dysfunction persisted into middle age even without exposure after adulthood. Moreover, the open field test and elevated plus maze indicated maternal low-level Pb, Hg, and Cd co-exposure triggered risk-taking behavior in weaning offspring, with a significant main effect for Pb exposure. No long-lasting effect on risk-taking behavior was detected in middle-aged offspring. Further investigation into molecular mechanisms showed that the dysregulation of corticosterone reaction and immune response might be the potential mechanism underlying Pb, Hg, and Cd co-exposure-induced cognitive impairments. Our study highlights the synergistic and long-lasting effects of multiple heavy metal exposures,underscoring the urgency to prevent exposure to metal mixtures among children and women of childbearing age.

Implications of Lead (Pb)-Induced Transcriptomic and Phenotypic Alterations in the Aged Zebrafish (Danio rerio).

Lead (Pb) is a well-known neurotoxin with established adverse effects on the neurological functions of children and younger adults, including motor, learning, and memory abilities. However, its potential impact on older adults has received less attention. Using the zebrafish model, our study aims to characterize the dose-response relationship between environmentally relevant Pb exposure levels and their effects on changes in behavior and transcriptomics during the geriatric periods. We exposed two-year-old zebrafish to waterborne lead acetate (1, 10, 100, 1000, or 10,000 µg/L) or a vehicle (DMSO) for 5 days. While lower concentrations (1-100 µg/L) reflect environmentally relevant Pb levels, higher concentrations (1000-10,000 µg/L) were included to assess acute toxicity under extreme exposure scenarios. We conducted adult behavior assessment to evaluate the locomotor activity following exposure. The same individual fish were subsequently sacrificed for brain dissection after a day of recovery in the aquatic system. RNA extraction and sequencing were then performed to evaluate the Pb-induced transcriptomic changes. Higher (1000-10,000 ug/L) Pb levels induced hyperactive locomotor patterns in aged zebrafish, while lower (10-100 ug/L) Pb levels resulted in the lowest locomotor activity compared to the control group. Exposure to 100 µg/L led to the highest number of differentially expressed genes (DEGs), while 10,000 µg/L induced larger fold changes in both directions. The neurological pathways impacted by Pb exposure include functions related to neurotransmission, such as cytoskeletal regulation and synaptogenesis, and oxidative stress response, such as mitochondrial dysfunction and downregulation of heat shock protein genes. These findings emphasize a U-shape dose-response relationship with Pb concentrations in locomotor activity and transcriptomic changes in the aging brain.

Heavy Metal Contamination in Soil and Health Risk Assessment through Onion Consumption in Mojo and Koka, Ethiopia

The objective of this study was to determine the concentration of heavy metals in the soil and horticultural crops grown under irrigation in the Mojo and Koka sites in Oromia, Ethiopia, and to evaluate the potential health risks that these metals may cause to consumers. For this investigation, a total of 50 onion (Allium porrum L.) and 50 soil samples were gathered. The content of heavy metals was measured using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) after the samples were digested using microwave-assisted digestion. The mean concentrations of examined trace elements in onion (mg/kg) were found in the range of 0.80 to 0.95, for As 1.77 to 0.91 for Sn, 2.09 to 1.49 for Pb, 12.29 to 7.31 for B, 13.85 to 12.33 for Zn, 0.34 to 0.25 for Cd, 1.83 to 1.78 for Hg, 11.29 to 7.54 for Cu, 0.83 to 0.78 for Ni, 0.34 to 0.31 for Co, 78.39 to 42.19 for Fe, 17.03 to 11.56 for Mn, and 1.03to 1.02 for Cr. Given that the average levels of Pb, Hg, Cd, and As in onions at both irrigation sites surpassed the upper limit of allowable levels established by the joint FAO/WHO commission. These metals’ concentrations in soil are found to be within acceptable bounds. As compared to other literatures, their concentration exceeded in both irrigation sites. According to the metal pollution load index, the overall pollution load of trace metals, including As, Pb, Cd, and Hg, was found to be moderately higher in both irrigation locations for the majority of the onions under study. The results, which were computed using an adult consumer’s food intake, indicated that the Pb and Hg dietary exposure levels were much higher than the daily intake amounts that were considered tentatively tolerated. The soil-to-onion transfer factor showed that whereas Fe has a strong sorption to the soil colloids, metal Cu is comparatively poorly maintained in the soil. The degree of metal enrichment in soils and sediments is higher than in other literature, according to the soil pollution indices. Thus, swift action is needed to stop the issue and guarantee public safety along the food system’s supply chain.

Identification of high lead exposure locations in Ohio at the census tract scale using a generalizable geospatial hotspot approach

BackgroundLead is a persistent, ubiquitous pollutant whose historical sources have been largely addressed through regulation and voluntary actions. The United States (U.S.) has achieved significant decreases in children’s blood lead levels (BLL) over the past 40 years; however, there is no known safe level of Pb exposure. Some communities continue to be disproportionately impacted by exposure to Pb, including Black children and families living in older homes.ObjectiveTo identify Ohio (OH) census tracts with children exposed to Pb and evaluate potential exposure determinants.MethodsWe obtained individual children’s blood Pb data from 2005–2018 in OH. The percent of children with elevated BLL (EBLL) was calculated for OH census tracts using three blood Pb reference values (3.5, 5, and 10 µg/dL). Getis-Ord Gi* geospatial hotspot or top 20th percentile methodologies were then applied to identify “hotspots.” Findings across multiple time periods and blood Pb reference values were evaluated and compared with existing Pb exposure indices and models.ResultsConsistency was observed across different blood Pb reference values, with the main hotspots identified at 3.5 µg/dL, also identified at 5 and 10 µg/dL. Substantial gains in public health were demonstrated, with the biggest decreases in the number of census tracts with EBLL observed between 2008–2010 and 2011–2013. Across OH, 355 census tracts (of 2850) were identified as hotspots across 17 locations, with the majority in the most populated cites. Generally, old housing and sociodemographic factors were indicators of these EBLL hotspots. A smaller number of hotspots were not associated with these exposure determinants. Variables of race, income, and education level were all strong predictors of hotspots.Impact statementThe Getis-Ord Gi* geospatial hotspot analysis can inform local investigations into potential Pb exposures for children living in OH. The successful application of a generalizable childhood blood Pb methodology at the census tract scale provides results that are more readily actionable. The moderate agreement of the measured blood Pb results with public Pb indices provide confidence that these indices can be used in the absence of available blood Pb surveillance data. While not a replacement for universal blood Pb testing, a consistent approach can be applied to identify areas where Pb exposure may be problematic.

Investigating the Influence of Heavy Metals and Environmental Factors on Metabolic Syndrome Risk Based on Nutrient Intake: Machine Learning Analysis of Data from the Eighth Korea National Health and Nutrition Examination Survey (KNHANES).

This study delves into the complex interrelations among nutrient intake, environmental exposures (particularly to heavy metals), and metabolic syndrome. Utilizing data from the Korea National Health and Nutrition Examination Survey (KNHANES), machine learning techniques were applied to analyze associations in a cohort of 5719 participants, categorized into four distinct nutrient intake phenotypes. Our findings reveal that different nutrient intake patterns are associated with varying levels of heavy metal exposure and metabolic health outcomes. Key findings include significant variations in metal levels (Pb, Hg, Cd, Ni) across the clusters, with certain clusters showing heightened levels of specific metals. These variations were associated with distinct metabolic health profiles, including differences in obesity, diabetes prevalence, hypertension, and cholesterol levels. Notably, Cluster 3, characterized by high-energy and nutrient-rich diets, showed the highest levels of Pb and Hg exposure and had the most concerning metabolic health indicators. Moreover, the study highlights the significant impact of lifestyle habits, such as smoking and eating out, on nutrient intake phenotypes and associated health risks. Physical activity emerged as a critical factor, with its absence linked to imbalanced nutrient intake in certain clusters. In conclusion, our research underscores the intricate connections among diet, environmental factors, and metabolic health. The findings emphasize the need for tailored health interventions and policies that consider these complex interplays, potentially informing future strategies to combat metabolic syndrome and related health issues.

Lead exposure and its relationship with fecal cortisol levels in black howler monkeys (Alouatta pigra).

Efficiently detecting early environmental threats to wildlife is vital for conservation. Beyond obvious dangers like habitat loss or deforestation, our study focuses on one of the most hazardous toxic metals for wildlife: lead (Pb). Pb is a widespread, cumulative, and insidious environmental pollutant that can trigger a wide range of physiological, biochemical, and behavioral disorders. In fact, Pb can cause permanent dysfunction of the major stress system, the hypothalamic pituitary adrenal (HPA) axis. We analyzed Pb and cortisol concentrations in fecal samples from Alouatta pigra in southern Mexico. Fecal samples were collected across six sites categorized as free-ranging (n = 65; conserved and disturbed) and from captive animals (n = 58). Additionally, we collected soil samples (n = 35). We found that Pb was present in 28% of fecal samples and 83% of soil samples. There was a positive relation between fecal and soil Pb levels, and fecal Pb concentration was negatively associated with cortisol levels. However, the claim of Pb being a direct interference with HPA axis requires further investigation. Given our findings, assessing wildlife exposure can be a valuable tool for understanding potential Pb exposure levels in the environment and its possible implications for human health. It can also serve as an early warning system of these consequences.

Heavy metals and trace elements in maternal blood and prevalence of congenital limb abnormalities among newborns: the Japan Environment and Children's Study.

Heavy metals such as lead (Pb) and cadmium (Cd) have been associated with adverse pregnancy and developmental outcomes, including congenital abnormalities. This study investigated the association between exposure to heavy metals and trace elements during fetal life and congenital limb abnormalities in infants. This study is based on a prospective ongoing nationwide birth cohort from the Japan Environment and Children's Study (JECS). The concentrations of Cd, Pb, mercury (Hg), selenium (Se), and manganese (Mn) were measured in maternal blood collected during the mid-late trimesters. Inclusion criteria were available from questionnaires filled in during pregnancy, including information about congenital limb abnormalities at birth or at one month. To examine the associations with limb anomalies and individual chemicals, logistic regression models were applied following log-transformation or division into quartiles of Cd, Pb, Hg, Se, and Mn concentrations. To assess the associations with the heavy metals and trace elements mixture, quantile g-computation was employed. All models were adjusted for age, maternal smoking history, maternal alcohol intake, history of smoking, and infant sex. Data from 90,163 participants were included in the analysis, of whom 369 had congenital limb abnormalities in any of the collected information, and 89,794 had none. Among the 369 cases of congenital limb abnormalities, there were 185 and 142 cases of polydactyly and syndactyly, respectively. The median concentrations of Pb, Cd, Hg, Se, and Mn were 5.85, 0.66, 3.64, 168, and 15.3 ng/g, respectively. There were no associations between maternal blood concentrations of Pb [adjusted odd ratio = 0.83; 95% confidence interval = 0.61, 1.11], Cd [0.87; 0.68, 1.10], Hg [0.88; 0.73, 1.07], Se [1.07; 0.44, 2.59], and Mn [0.91; 0.64, 1.30] with congenital limb abnormalities. No significant association was observed between the mixture of heavy metals and trace elements [0.85; 0.72, 1.02] and any congenital limb abnormalities. Moreover, there was no association with all polydactylies and all syndactylies, or any type of abnormality as a subdivision. At the maternal exposure levels of Cd, Pb, Hg, Se, and Mn assessed in the present study, no association was identified with the risk of developing congenital limb abnormalities in children.

Adequate Intake of Dietary Fiber May Relieve the Detrimental Impact of Blood Lead on Dyslipidemia among US Adults: A Study of Data from the National Health and Nutrition Examination Survey Database.

Lead (Pb) exposure is a well-established risk factor for dyslipidemia, and people are exposed to it in multiple ways daily. Dietary fiber is presumed to improve lipid metabolism disorders, but it is still unknown whether it can relieve the detrimental impact of Pb on dyslipidemia. We used publicly accessible data from the 2011-2016 cycles of the National Health and Nutrition Examination Survey (NHANES). A total of 2128 US adults were enrolled for the subsequent analysis. Heavy metal concentrations in blood were measured using inductively coupled plasma mass spectrometry (ICP-MS). A weighted logistic regression was conducted to calculate odds ratios (ORs) and 95% confidence intervals (CIs). The dose-response relationship between blood heavy metals and dyslipidemia was explored using a weighted restricted cubic spline (RCS) analysis. After fully adjusting for potential confounding factors (age, gender, race, education level, ratio of family income to poverty, marital status, body mass index, physical activity, waist circumference, smoke, alcohol drinking and history of metabolic syndrome, hypertension, and diabetes), a positive association between blood Pb levels and dyslipidemia risk was revealed (OR = 1.20, 95% CI: 1.03-1.40). Dietary fiber intake may significantly modify the association between blood Pb levels and dyslipidemia (p-interaction = 0.049), with a stronger association (OR = 1.26, 95% CI: 1.05-1.52) being revealed in individuals with an inadequate intake of dietary fiber (<14 g/1000 kcal/day), but a null association (OR = 1.01, 95% CI: 0.72-1.42) being observed in those with an adequate intake of dietary fiber (≥14 g/1000 kcal/day). Moreover, the weighted RCS analysis showed that compared with the average blood Pb exposure level (4.24 µg/dL), a lower blood Pb exposure level (3.08 µg/dL) may contribute to the risk of dyslipidemia in the group with an inadequate dietary fiber intake. Our findings suggest that Pb exposure in blood may be a risk factor for dyslipidemia. However, an adequate dietary fiber intake may offset the risk of dyslipidemia caused by blood Pb exposure. Since avoiding Pb exposure in daily life is difficult, increasing dietary fiber intake in the future might be a promising approach to alleviate dyslipidemia caused by Pb exposure.

Assessing heavy metal levels in pediatric enteral nutrition formulas available in the Turkish market: Implications for consumer health.

In this study, we assessed the levels of lead (Pb), cadmium (Cd), mercury (Hg), and inorganic arsenic (iAs) in 27 pediatric enteral nutrition (EN) formulas from five international brands available in the Turkish market. Analysis was conducted using inductively coupled plasma mass spectrometry (ICP-MS). Non-carcinogenic and carcinogenic risk assessment was performed using hazard quotient (HQ), hazard index (HI), carcinogenic risk (CR), Toxicological contribution % of Provisional Tolerable Weekly Intake (PTWI) models. Our objective was to evaluate heavy metal exposure in EN formulas, specifically focusing on Cd, Pb, iAs, and Hg levels according to recommended amounts for different age groups based on their energy requirements. Average concentrations of iAs in polymeric (PC), oligomeric (OC), and monomeric (MC) EN formulas were as follows: PC: 2.13±0.16 (<LOD-13.86) μg/kg, OC: 4.29±0.10 (0.38-11.98) μg/kg, MC: 8.62±0.19 (1.60-27.20) μg/kg. For Cd levels, average concentrations in PC, OC, and MC formulas were: PC: 0.57±0.03 (<LOD-3.09) μg/kg, OC: 1.31±0.07 (0.40-3.12) μg/kg, MC: 0.93±0.07 (0.07-2.33) μg/kg. Similarly, average concentrations of Hg in PC, OC, and MC formulas were: PC: 0.13±0.01 (<LOD-0.14) μg/kg, OC: 0.18±0.01 (<LOD-0.18) μg/kg, MC: 0.20±0.02 (<LOD-0.34) μg/kg. Lastly, average concentrations of Pb in PC, OC, and MC formulas were: PC: 2.32±0.06 (1.52-2.96) μg/kg, OC: 0.97±0.06 (0.37-2.26) μg/kg, MC: 2.58±0.08 (1.95-3.28) μg/kg. The exposure levels of Cd, Pb, iAs, and Hg calculated in this study did not exceed the PTWI threshold values established by the European Food Safety Authority (EFSA). Average HQ values for each heavy metal exposure in males and females were below 1. However, P95 values for iAs exceeded 1.00 in all age groups. The HI value was greater than 1.00 in all age groups and genders. The presence of heavy metals in EN formulas may pose health risks, particularly for sensitive individuals.

Lead exposure suppresses the Wnt3a/β-catenin signaling to increase the quiescence of hematopoietic stem cells via reducing the expression of CD70 on bone marrow-resident macrophages.

Lead (Pb) is a heavy metal highly toxic to human health in the environment. The aim of this study was to investigate the mechanism of Pb impact on the quiescence of hematopoietic stem cells (HSC). WT C57BL/6 (B6) mice treated with 1250 ppm Pb via drinking water for 8 wk had increased the quiescence of HSC in the bone marrow (BM), which was caused by the suppressed activation of the Wnt3a/β-catenin signaling. Mechanically, a synergistic action of Pb and IFNγ on BM-resident macrophages (BM-Mφ) reduced their surface expression of CD70, which thereby dampened the Wnt3a/β-catenin signaling to suppress the proliferation of HSC in mice. In addition, a joint action of Pb and IFNγ also suppressed the expression of CD70 on human Mφ to impair the Wnt3a/β-catenin signaling and reduce the proliferation of human HSC purified from umbilical cord blood (UCB) of healthy donors. Moreover, correlation analyses showed that the blood Pb concentration was or tended to be positively associated with the quiescence of HSC, and was or tended to be negatively associated with the activation of the Wnt3a/β-catenin signaling in HSC in human subjects occupationally exposed to Pb. Collectively, these data indicate that an occupationally relevant level of Pb exposure suppresses the Wnt3a/β-catenin signaling to increase the quiescence of HSC via reducing the expression of CD70 on BM-Mφ in both mice and humans.

Assessment of Diagnostic Accuracy and Clinical Utility of DNA Methylation (5-mC) in Detecting Severity of Occupational Lead Exposure.

This study investigated the diagnostic accuracy (DA) and clinical utility (CU) of DNA methylation (5 methylcytosine) in occupational Pb-exposure from Pb based industry. Blood Lead levels (BLLs) were measured using the ICP-OES method. The total DNA methylation (5-mC) was quantified using ELISA method. Based on their BLLs, the Pb-exposed workers were categorised into three groups: low (< 10µg/dL), moderate (10-30µg/dL), and high exposure (> 30µg/dL). DNA methylation (5-mC) was significantly lower in moderate and high Pb-exposure groups when compared to the low Pb-exposure group. Workers exposed to high levels of Pb-exposure, the DA variables of 5-mC showed that the sensitivity was 74.7% [95% CI 65.4-84.0], specificity was 69.6% [95% CI 50.8-88.4], positive predictive value (PPV) was 89.9% [95% CI 82.7-97.0], Postive likelihood ratio (LR+) was 2.454 [95% CI 1.3-4.6], and diagnostic odds ratio (DOR) is 6.3 [95% CI 6.5-7.7]. In moderate Pb-exposure, the DA variables of 5-mC revealed that the sensitivity is 64.9% [95% CI 55.2-74.5], the specificity is 69.6% [95% CI 50.8-88.4], the PPV is 89.7% [95% CI 82.5-97.0], the LR+ is 2.132 [95% CI 1.13-4.03], and the DOR is 4.2 [95% CI 3.6-5.7]. The high Pb-exposure group had higher DA metrics when compared to moderate Pb exposure. The clinical utility (CU+) of 5-mC was found to have good utility of 0.671 [95% CI 0.566-0.776] in the high Pb exposure group and fair utility of 0.582 [95% CI 0.470-0.694] in moderate Pb exposure group. In conclusion, DNA methylation (5mC) could be used as a predictive biomarker for high Pb-exposure.

Interaction between blood cadmium and lead concentration and physical activity on hypertension from the Korean national health and nutrition examination survey in 2008–2013

BackgroundPrevious studies have suggested that blood Cd, Pb exposure, and physical activity levels may influence the development of hypertension. This study aimed to investigate the relationship between blood Cd, Pb levels, and hypertension by the level of physical activity in Korean adults using The Korea National Health and Nutrition Examination Survey (KNHANES).MethodsWe used data from the KNHANES (2008–2013), a nationally representative, cross-sectional, population-based study. We included 8,510 participants who had records of blood Cd, Pb and, blood pressure measurements. Multiple logistic regression was used to examine the association between blood Cd and Pb exposure and the development of hypertension, as well as the modifying effects of physical activity levels. Additive interaction was estimated using relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP) and synergy index (S).ResultsFollowing covariates adjustments, we found significant associations of blood Cd and Pb with higher hypertension prevalence. This association was more apparent in low physical activity while blood Cd and Pb concentrations were not significantly associated with hypertension in participants with more activity. Additionally, there was a significant interaction between blood Cd and physical activity on hypertension risk (RERI = 0.17, 95% CI: -0.36–0.7; AP = 0.12, 95% CI: -0.28–0.52; S = 1.75, 95% CI:1.36–2.14).ConclusionsOur results suggest that low physical activity may substantially amplify the adverse effects of blood Pb and Cd exposure on hypertension risk. However, interactions were only found for Cd. Further studies are needed to confirm these findings.

Necessity of introducing particle size distribution of hand-adhered soil on the estimation of oral exposure to metals in soil: Comparison with the traditional method

This study aimed to systematically investigate the relationship between children exposure possibility, metal concentration, metal bioaccessibility and soil particle size. fifty Children aged 3–8 years were recruited for the collection of hand-adhered soil, environmental soil, and blood samples. The mass distribution of hand-adhered soil with particle size were analyzed. Based on it, environmental soil samples were divided into five fractions to evaluate the effect of soil particle size on the total contents and bioaccessibilities of toxic metals. Then, a refined soil oral exposure model based on the particle size distribution of hand-adhered soil was established, and the estimation was compared with the typical traditional method. We found that finer particles were preferentially adhered to hand. The highest metal concentrations and bioaccessibilities occurred in the finest fraction, with values decreasing with increasing particle size. The exposure levels using the refined model were 2.0–3.4 times higher than those with the traditional method. In addition, Pb exposure level calculated using the refined model exhibited stronger and more significant correlation with blood Pb than those of the traditional soil. The construction of a refined exposure scenario based on hand-adhered soil could more exactly reflect the real exposure level and the difference among individuals.

Sources of Lead Exposure in West Africa

This commentary is an investigation of sources of lead (Pb) exposure in West Africa. Pb is generally acknowledged as one of the most widespread environmental health hazards in West Africa, and there is heightened concern over adverse health effects at various levels of exposure (at doses once considered safe) in the West African region. A literature review for the possible health implications of Pb exposure on human health showed nervous system dysfunction, anemia, and potential cognitive diseases as the major health issues among children, while adults were found to suffer more from cardiovascular dysfunction, neurological decline, and reproductive diseases. Despite a decline in blood lead levels (BLLs), lead exposure continues to be a major public health concern as no level of Pb exposure can be considered safe. Moreover, lowering BLLs entails identifying various lead sources such as gasoline emissions, leaded paint, canned foods, and beverages, as well as plausible biological pathways of lead exposure and response. However, only countries such as Nigeria and Ghana have extensive research available regarding the different sources of Pb exposure. Further, it is not apparent which country is affected the most by Pb exposure. Therefore, this commentary was aimed to explore different literature sources to describe and list the different sources of Pb exposure in 15 West African countries. The findings indicated water, food, and occupational exposure as the major sources of Pb exposure in the region. People with occupations such as e-waste and Pb acid battery recycling, auto mechanics, fuel attending, welding, electronic repairing, farming/spraying, and mining were found to be at immediate risk. Tobacco, spices and paints constituted additional potential sources of exposure. For residents living near landfills or urban area, the major sources of Pb exposure were soil, air, and dust particles. The review revealed a vast research gap on the sources and implications of Pb exposure. Exposure to Pb could further increase due to uncontrolled traffic, urban growth, inadequate urban planning, and the inadequate enforcement of regulations. Therefore, more extensive research on the changing trends of Pb exposure among West African populations is needed.

Public Health Implications and Possible Sources of Lead (Pb) as a Contaminant of Poorly Regulated Kratom Products in the United States.

Kratom (Mitragyna speciosa) is a tropical tree that is indigenous to Southeast Asia. Kratom leaf products have been used in traditional folk medicine for their unique combination of stimulant and opioid-like effects. Kratom is being increasingly used in the West for its reputed benefits in the treatment of pain, depression, and opioid use disorder (OUD). Recent studies from the United States Food and Drug Administration (FDA, Silver Spring, MD, USA) and our laboratory have shown that many kratom products being sold in the United States are contaminated with potentially hazardous levels of lead (Pb). In this commentary, we discuss the public health implications of the presence of Pb in kratom products, particularly as they relate to the predicted levels of Pb exposure among kratom users. We also considered the specific toxic effects of Pb and how they might relate to the known physiologic and toxicologic effects of kratom. Finally, we consider the possible sources of Pb in kratom products and suggest several areas for research on this issue.

Pollution characteristics, influencing factors and health risks of personal heavy metals exposure: Results from human environmental exposure study in China

Heavy metals can directly enter the alveolus through respiration and react with proteins and enzymes, leading to various adverse effects on human health. This study aimed to identify the main influencing factors contributing to personal exposure, and the relationships between indoor and outdoor air and personal exposure. A total of 107 paired indoor, outdoor, and personal exposure samples were collected during non-heating and heating periods from urban and rural areas of six typical cities in China. Personal exposure levels of Hg, As, Cd, and Pb during the non-heating period were 0.07, 20.43, 0.53, and 29.97 ng/m3, and that were 0.08, 28.47, 2.26, and 16.26 ng/m3 during the heating period, respectively. Personal exposure levels of heavy metals showed temporal, urban-rural, and regional discrepancies. The personal heavy metal exposure was lower than indoors but higher than outdoors, and significantly relative to indoor air for all cities. Heating type and ventilation duration were influence factors of indoor air. Smoking, cooking, heating, and ventilation duration all affected personal exposure of heavy metal. There were non-carcinogenic from personal inhalation of As but the carcinogenic risks of Hg, As, Cd, and Pb were acceptable. Indoor air pollution was the main contributor to personal inhalation health risk. So we should pay more attention to the activity patterns related to indoor air.

Release of lead from Renaissance lead-glazed ceramics from southern Denmark and northern Germany: implications from acetic acid etching experiments

Lead-glazed potsherds from archaeological excavations at six Renaissance (1536–1660 CE) sites in southern Denmark and northern Germany have been subjected to etching experiments using 4 wt% acetic acid. The extracts of 45 sherds were analysed by Inductively Coupled Plasma Mass Spectrometry. At one site, the ducal hunting castle of Grøngaard, Pb levels in acid extracts from glazed dishes were so high (up to 29,000 µg Pb cm−2 day−1) that acute toxic effects likely occurred if the dishes were used for serving food containing vinegar. More moderate acid-etching Pb levels were found in dishes from other sites, but they still exceed the WHO critical level if used daily. Acetic acid etching experiments performed on pipkins (three-legged cooking pots with a handle) yielded somewhat lower Pb extract values, averaging ca. 25 µg Pb cm−2 day−1. Taking into account the widespread use of pipkins for cooking, they might easily have led to a higher weekly Pb intake than the use of the moderate-level dishes. The question remains whether such high levels of Pb exposure during meals led to injurious Pb intake. Prior skeletal analyses have shown that medieval to early modern individuals from the area, especially in towns, were exposed to Pb. While exposure could have come from various sources other than lead-glazed ceramics, such as cosmetics, paint, antibacterial ointments, and lead water pipes, widely distributed lead-glazed ceramics had the potential of being a main source of Pb. How the pottery was actually used is uncertain, and it certainly was not evenly distributed across all segments of society, but the etching experiment results suggest that severe poisonous effects could have resulted from the use of lead-glazed Renaissance ceramics.

Association between cadmium and lead co-exposure, blood pressure, and hypertension: a cross-sectional study from northwest China

Cadmium (Cd) and lead (Pb) co-exposure have been inconsistently associated with blood pressure (BP) and hypertension (HTN). This cross-sectional study included 309 participants who completed a health examination and had blood Cd (Cd-B) and Pb (Pb-B) levels measured. The association between Cd, Pb, and their combined exposure levels, with systolic (SBP) and diastolic blood pressure (DBP) and HTN was evaluated using models which were stratified according to sex, age, BMI, and smoking habit categories. The results found both increasing Cd-B and Pb-B were associated with elevated SBP and DBP in the overall population. In addition, increases in Cd-B and Pb-B were also associated with increased risk of HTN in overall and stratified models. Moreover, compared with the low exposure group, co-exposure to high levels of Cd and Pb was associated with increased SBP (β = 10.95, 95% CI: 5.69, 16.21), increased DBP (β = 5.09, 95% CI: 1.53, 8.66), and increased HTN risk (OR = 2.45, 95% CI: 1.15, 5.21) in the overall model, and above results were different in the stratified model. This study provides evidence of an association between Cd and/or Pb exposure levels, BP, and HTN. However, the significance of this association differed according to sex, age, BMI, and smoking habit. Highlights Cadmium/lead exposure is associated with elevated blood pressure and hypertension. Cadmium and lead co-exposure increased blood pressure in a dose-dependent manner. Results revealed differences according to sex, age, BMI, and smoking habit category. Health oversight should be implemented for residents with high heavy metal exposure.

Reliability and accuracy analysis of time-weighted average exposure to heavy metals based on personal exposure

Time-weighted average (TWA) exposure has been used as a surrogate for personal air exposure in some large-scale studies. However, the uncertainties of TWA exposure remain to be determined, although its boundedness has been widely recognized. This study aims to evaluate the reliability and accuracy of TWA exposure based on personal exposure. A total of 180 combined indoor-outdoor-personal air samples were collected of six cities during the non-heating and heating periods. The personal exposure levels of Hg, As, Cd, and Pb were 0.16, 21.20, 0.74, and 34.47 ng/m3 in the non-heating period, respectively, but were 0.20, 34.53, 3.45, and 18.59 ng/m3 in the heating period, respectively. The ratios of TWA and personal exposure of heavy metal(loid)s ranged from 0.91 to 1.53. Indoor pollution was the most significant factor of TWA exposure, accounting for 78.3–97.6% and 88.4–98.6% in the heating and non-heating period, respectively. Based on the results of redundancy analysis and risk assessment by TWA exposure, we concluded that TWA exposure could be used for qualitative investigation, as a substitute for personal exposure, but it may result in large bias when used for quantitative investigation. Larger sample size and more exposure scenarios can reduce the estimation error of TWA.

Exposure to multiple toxic metals and the risk of early embryonic arrest among women undergoing assisted reproductive techniques

BackgroundEarly embryonic arrest is a great challenge for in vitro fertilization. Whether exposure to toxic metals is associated with an increased risk of early embryonic arrest warrants investigation. ObjectivesHere, we conducted a case-control study in infertile women to estimate the associations between blood barium (Ba), arsenic (As), mercury (Hg), and lead (Pb) exposure levels and the risk of early embryonic arrest. MethodsBa, As, Hg, and Pb exposure levels in fasting blood collected from 74 infertile women (123 cycles) with early embryonic arrest and 157 infertile women (180 cycles) without early embryonic arrest were measured by ICP–MS. Bayesian kernel machine regression (BKMR) was used to assess the association of exposure level of toxic metals mixture with the risk of early embryonic arrest as well as to evaluate which metal playing a leading role in the association, and then generalized estimating equations (GEEs) were used to evaluate the relationship between the selected harmful metal and the risk of early embryonic arrest. Finally, the potential causes of early embryonic arrest originating from the harmful metal exposure were explored. ResultsBlood Ba levels were significantly higher in the case group than that in the control group (p = 0.009) rather than As, Pb and Hg. Results from BKMR showed that exposure to toxic metals mixture increased the risk of early embryonic arrest, with Ba playing a leading role (PIP = 0.9612). GEE analysis showed that high Ba exposure level was related with the increased risk of early embryonic arrest (p < 0.05) and it impacted on the oogenesis significantly. ConclusionsOur study found that exposure to toxic metals mixture was associated with the increased risk of early embryonic arrest, and Ba contributed most to the increased risk. Higher Ba exposure in whole blood corresponds to a higher risk of early embryonic arrest and impacted on the oogenesis significantly.