Hepatobiliary-Related Outcomes in US Adults Exposed to Lead

Investigating the Interplay of Toxic Metals and Essential Elements in Liver Disease

Liver diseases, including non-alcoholic fatty liver disease (NAFLD), are a growing global health issue. Environmental exposure to toxic metals can harm the liver, increasing the risk of NAFLD. Essential elements are vital for liver health, but imbalances or deficiencies can contribute to the development of NAFLD. Therefore, understanding the interplay between toxic metals and essential elements in liver disease is important. This study aims to assess the individual and combined effects of toxic metals (lead(Pb), cadmium (Cd), mercury (Hg)), and essential elements (manganese and selenium) on the risk of liver disease. Methods: We assessed the individual and combined effects of Pb, Cd, Hg, manganese (Mn), and selenium (Se) on liver disease risk using data from the National Health and Nutrition Examination Survey between 2017 and 2018. We performed descriptive statistics and linear regression analysis and then utilized Bayesian Kernel Machine Regression (BKMR) techniques such as univariate, bivariate, and overall effect analysis. BKMR enabled the assessment of non-linear exposure-response functions and interactions between metals and essential elements. Posterior Inclusion Probabilities (PIPs) were calculated to determine the importance of each metal and essential element in contributing to liver disease. Regarding our study results, the regression analysis of liver injury biomarkers ALT, AST, ALP, GGT, total bilirubin, and the FLI-an indicator of NAFLD-with toxic metals and essential elements, adjusting for covariates such as age, sex, BMI, alcohol consumption, ethnicity, income, and smoking status, demonstrated the differential effects of these contaminants on the markers of interest. Our BKMR analysis provided further insights. For instance, the PIP results underscored Pb's consistent importance in contributing to liver disease (PIP = 1.000), followed by Hg (PIP = 0.9512), Cd (PIP = 0.5796), Se (PIP = 0.5572), and Mn (PIP = 0.4248). Our univariate analysis showed a positive trend with Pb, while other exposures were relatively flat. Our analysis of the single-variable effects of toxic metals and essential elements on NAFLD also revealed that Pb significantly affected the risk of NAFLD. Our bivariate analysis found a positive (toxic) trend when Pb was combined with other metals and essential elements. For the overall exposure effect of exposure to all the contaminants together, the estimated risk of NAFLD showed a steady increase from the 60th to the 75th percentile. In conclusion, our study indicates that Pb exposure, when combined with other toxic metals and essential elements, plays a significant role in bringing about adverse liver disease outcomes.

Association of Combined PFOA, PFOS, Metals and Allostatic Load on Hepatic Disease Risk

This study utilizes the National Health and Nutrition Examination Survey (NHANES) 2017-2018 data to explore the relationship between exposure to perfluoroalkyl substances (specifically perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), metals lead (Pb), mercury (Hg), and cadmium (Cd), allostatic load, and hepatic disease markers, including the fatty liver index a measure of the likelihood of non-alcoholic fatty liver disease, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and total bilirubin. The paper identified significant associations and interaction effects by employing descriptive statistics, Spearman's correlation analysis, linear regression, and Bayesian kernel machine regression (BKMR). Descriptive statistics highlight sex-specific differences in contaminant levels. Spearman's analysis underscores strong correlations among metals and per- and polyfluoroalkyl substances (PFAS). Linear regression reveals significant impacts of specific contaminants on AST, ALT, ALP, and bilirubin levels, adjusting for age and alcohol consumption. BKMR results further elucidate the complex, potentially synergistic relationships between these environmental exposures and the likelihood of non-alcoholic fatty liver disease, offering nuanced insights into their combined effects on liver health. The findings emphasize the intricate dynamics of environmental exposures on hepatic function, advocating for targeted public health interventions.

Potential diagnostic biomarkers for lead-induced hepatotoxicity and the role of synthetic chelators and bioactive compounds

Lead (Pb2+) poisoning is a public health concern of global dimensions. Although several public health guidelines and workplace safety policies are existing and enforced, lead toxicity cases are drastically increasing. Lead exposure leads to numerous harmful consequences and causes adverse effects on different body organs and systems, mainly via the generation of reactive oxygen species, leading to augmented oxidative stress, competing with metal ions, and binding with the sulfhydryl groups. In several instances, lead poisoning cases remain undiagnosed and untreated or receive only symptomatic treatment. Estimation of blood lead levels reflects only a recent exposure, however, which does not reveal the total body burden. This review summarizes the effects of lead with special reference to hepatotoxicity and some of the potential diagnostic biomarkers. Furthermore, it also focuses on synthetic chelators used in the treatment of lead poisoning and the advantage of using bioactive compounds with an emphasis on the ameliorative effect of garlic.

Co-supplementation of Zinc and Calcium Suppresses Bio-absorption of Lead in Sprague Dawley Rats

Lead (Pb) is a widespread environmental toxicant and its toxicity causes huge health impacts. The present study was conducted to examine the protective role of zinc (Zn) and calcium (Ca) supplements against bio-absorption of Pb in blood and organs including the liver and kidney. Hence, Sprague Dawley rats were divided in to five groups. G₁ served as negative control and was provided with standard diet, G₂ as positive control receiving standard diet + PbAc (20 mg/kg BW), G₃ was provided with standard diet + PbAc (20 mg/kg BW) + ZnSO₄ (20 mg/kg BW), G₄ with standard diet + PbAc (20 mg/kg BW) + CaCO₃ (7.5 g/kg BW) whereas G₅ was fed on standard diet + PbAc (20 mg/kg BW) + ZnSO₄ (20 mg/kg BW) + CaCO₃ (7.5 g/kg BW). The salts were provided as solution, dissolved in 0.5 mL distilled water via orogastric tube. After 35 days, the overnight fasted rats were decapitated, and blood and organs were collected for analysis of levels of metals and liver and kidney function tests. The results depicted significant decrease in Pb concentration in blood and organs while increase in Zn and Ca absorption was observed as a result of Zn and Ca supplementation with Zn being better than Ca alone, specially however, combined effect of these supplements was more profound in improving liver and kidney stress biomarkers and maintained the normal architecture of renal and hepatic parenchyma. It was concluded that Zn and Ca co-supplementation hinder Pb absorption in blood, the liver, and kidney thus suggesting that their intake may protect from Pb toxicity.

Combined Effect of Lead Exposure and Allostatic Load on Cardiovascular Disease Mortality-A Preliminary Study

This study explores the combined effect of lead (Pb) exposure and an index of chronic physiological stress on cardiovascular disease mortality using data from the National Health and Nutrition Examination Survey (NHANES) 1999-2008 linked to 1999-2014 National Death Index data. Chronic physiological stress was measured using the allostatic load (AL) index, which was formed by analyzing markers from the cardiovascular, inflammatory, and metabolic systems, with Pb levels, assessed using blood lead levels (BLL). The dataset was analyzed with statistical techniques to explore (a) the relationship between Pb exposure and AL, and (b) the combined role of Pb and AL on cardiovascular disease mortality. Results indicated that AL was more elevated in those with BLLs above the 50th percentile in the US population and that those with elevated AL were more likely to have high BLL. Finally, the interaction of AL and BLL significantly increased the likelihood of cardiovascular disease mortality. These findings highlight the need for considering the totality of exposures experienced by populations to build holistic programs to prevent Pb exposure and reduce stressors to promote optimal health outcomes and reduce cardiovascular mortality risk.

Biosorption of Heavy Metals by the Bacterial Exopolysaccharide FucoPol

Despite the efforts for minimizing the usage of heavy metals, anthropogenic activities still generate high amounts of wastewater containing these contaminants that cause significant health and environmental problems. Given the drawbacks of the conventional physical and chemical methods currently used, natural biosorbents (microbial cells or their products) arise as promising environmentally friendly alternatives. In this study, the binding efficiency of the polysaccharide secreted by Enterobacter A47, FucoPol, towards lead (Pb2+), cobalt (Co2+), copper (Cu2+) and zinc (Zn2+) cations was demonstrated. FucoPol revealed a higher performance for the biosorption of Pb2+, with a maximum overall metal removal of 93.9 ± 5.3% and a specific metal uptake of 41.1 ± 2.3 mg/gEPS, from a Pb2+ solution with an initial concentration of 10 mg/L, by a 5 g/L FucoPol solution. The overall metal removal decreased considerably (≤31.3 ± 1.6%) for higher Pb2+ concentrations (48 and 100 mg/L) probably due to the saturation of FucoPol’s binding sites. Pb2+ removal was also less efficient (66.0 ± 8.2%) when a higher FucoPol concentration (10 g/L) was tested. Pb2+ removal efficiency of FucoPol was maximized at pH 4.3, however, it was affected by lower pH values (2.5–3.3). Moreover, the FucoPol’s sorption performance was unaffected (overall metal removal: 91.6–93.9%) in the temperature range of 5–40 °C. These findings demonstrate FucoPol’s great potential for utilization as a biodegradable and safe biosorbent for treating waters and wastewaters contaminated with Pb2+.

Cumulative Effects of Low-Level Lead Exposure and Chronic Physiological Stress on Hepatic Dysfunction-A Preliminary Study

Chronic physiological stress and hepatic injury were explored in this cross-sectional study using data from the National Health and Nutrition Examination Survey (NHANES) 2007–2010. Lead exposure was measured using Blood Lead Levels (BLL), which were divided into quartiles of exposure based on the distribution within the database. Allostatic load (AL), a variable representing chronic physiological stress, was operationalized using ten clinical markers. The geometric mean values for markers of liver injury of interest (a) Aspartate Aminotransferase (AST), (b) Alanine Aminotransferase (ALT), (c) Alkaline Phosphatase (ALP), and (d) Gamma glutamyl-transferase (GGT) were explored in quartiles of lead exposure. Associations between AL and AST, ALT, ALP, and GGT among those exposed to lead were analyzed using linear regression models. In examining lead exposure in increasing quartiles, the geometric mean of the liver injury markers showed significant elevations as lead exposure levels increased. Simple linear regression revealed AL was positively associated with several markers of hepatic injury in all degrees of lead exposure. This study demonstrates the potential dangers of social and environmental exposures to liver health.

Exposure to Heavy Metals in Electronic Waste Recycling in Thailand

Electronic waste recycling can release heavy metals into the environment and cause adverse health effects. We assessed the association between exposure to heavy metals from electronic waste recycling and the prevalence of asthma in a nested case-control study of 51 subject pairs with and without asthma. House dust, airborne dust, blood, and urine were collected from residents of two neighboring sites in Ubon Ratchathani province, Thailand. Multiple electronic waste-handling activities are conducted in the first site, while the second site is mostly agricultural. Concentrations of chromium, mercury, nickel, and lead in house dust and airborne dust were higher in the electronic waste-handling site (p < 0.05), but levels of exposure were similar in subjects with and without asthma. Although we did not find an association between exposure to these metals and the prevalence of asthma, control measures should be implemented to reduce health risks from long-term exposure to heavy metals.

Effects of Vitamin D Receptor, Metallothionein 1A, and 2A Gene Polymorphisms on Toxicity of the Peripheral Nervous System in Chronically Lead-Exposed Workers

Chronic exposure to lead is neurotoxic to the human peripheral sensory system. Variant vitamin D receptor (VDR) genes and polymorphisms of metallothioneins (MTs) are associated with different outcomes following lead toxicity. However, no evidence of a relationship between lead neurotoxicity and polymorphisms has previously been presented. In this study, we investigated the relationship between the polymorphisms of VDR, MT1A, and MT2A genes and lead toxicity following chronic occupational lead exposure. We measured vibration perception thresholds (VPT) and current perception thresholds (CPT) in 181 workers annually for five years. The outcome variables were correlated to the subject's index of long-term lead exposure. Polymorphisms of VDR, MT1A, and MT2A were defined. The potential confounders, including age, sex, height, smoking, alcohol consumption, and working life span, were also collected and analyzed using linear regression. The regression coefficients of some gene polymorphisms were at least 20 times larger than regression coefficients of time-weighted index of cumulative blood lead (TWICL) measures. All regression coefficients of TWICL increased slightly. MT1A rs11640851 (AA/CC) was associated with a statistically significant difference in all neurological outcomes except hand and foot VPT. MT1A rs8052394 was associated with statistically significant differences in hand and foot CPT 2000 Hz. In MT2A rs10636, those with the C allele showed a greater effect on hand CPT than those with the G allele. Among the VDR gene polymorphisms, the Apa rs7975232 (CC/AA) single nucleotide polymorphism was associated with the greatest difference in hand CPT. MT2A rs28366003 appeared to have a neural protective effect, whereas Apa (rs7975232) of VDR and MT2A rs10636 increased the neurotoxicity as measured by CPT in the hands. MT1A rs8052394 had a protective effect on large myelinated nerves. MT1A rs11640851 was associated with susceptibility to neurotoxicity.

Simultaneous Removal of Residual Sulfate and Heavy Metals from Spent Electrolyte of Lead-Acid Battery after Precipitation and Carbonation

Spent electrolyte from lead-acid battery contains high concentrations of sulfate acid and heavy metals; therefore without proper handling, they might cause severe environmental pollution. A relatively high concentration of sulfate ions (approximately 3000 mg/L) and heavy metals still exists in the effluent even after precipitation with slaked lime and carbonation process, which need to be further processed to lower both the concentrations of sulfate and heavy metals for direct discharge. A process that involves the reduction of sulfate to sulfide with sulfate-reducing bacteria and precipitation of the excessive sulfide with Fe(OH)2 was adopted to dispose of the effluent after precipitation and carbonation for direct discharge. Thermodynamic calculations were adopted to narrow down the optimum experimental range and understand the precipitation mechanism. In the whole process, no new impurities nor ions were introduced and 99.2% of sulfate, 99.9% of sulfide, 99.1% of Ca and more than 94.6% of Pb and 99.8% of Cd were removed and the obtained effluent was safe to discharge.

Lead Exposure and Cardiovascular Disease among Young and Middle-Aged Adults

Lead and its effects on cardiovascular-related markers were explored in this cross-sectional study of young adults (18–44 years) and middle-aged adults (45–65 years) from the United States using the National Health and Nutrition Examination Survey (NHANES), 2009–2016. Degrees of exposure were created using blood lead level (BLL) as the biomarker of exposure based on the epidemiologically relevant threshold of BLL > 5 μg/dL. The mean values, in addition to the percentages of people represented for the markers of interest (systolic blood pressure [SBP], diastolic blood pressure [DBP], gamma-glutamyl transferase [GGT], non-high-density lipoprotein cholesterol [non-HDL-C]) were explored. Among those exposed to lead, the likelihood of elevated clinical markers (as defined by clinically relevant thresholds of above normal) were examined using binary logistic regression. In exploring exposure at the 5 μg/dL levels, there were significant differences in all the mean variables of interest between young and middle-aged adults. The binary logistic regression showed young and middle-aged adults exposed to lead were significantly more likely to have elevated markers (apart from DBP). In all, lead affects cardiovascular-related markers in young and middle-aged U.S. adults and thus we must continue to monitor lead exposure to promote health.

Household Smoking Status and Heavy Metal Concentrations in Toenails of Children

There is limited evidence on the distribution of heavy metals and its association with secondhand smoking (SHS) within Pacific Island children living in New Zealand. Certain heavy metals such as cadmium (Cd), lead (Pb), and aluminum (Al) bioaccumulates in the body and can deteriorate health in both children and adults. Others, such as chromium (Cr) and nickel (Ni) in trace amounts are necessary but become toxic at high levels. Exposure routes of these elements include food, water, and air. The purpose of this study was to identify the distribution of toxic metal concentrations and its possible correlation with SHS within the Pacific Island children. A sub-sample of children within Pacific Island families longitudinal study, at the nine-year phase, who were living in the New Zealand city of Auckland were invited to participate, (n = 278). Toenails were used as a biomarker to determine Cr, Pb, Cd, Cu, Ni, and Al concentration using inductively coupled plasma mass spectrometry. Reliable and validated questionnaires were used for demographics, lifestyle, and health outcome variables. Significant differences between household smoking status and ethnicity, as well as parents' marital status, were observed (p < 0.05). There was no statistical difference in heavy metal concentrations in smoking versus non-smoking households. However, Cr, Pb, Cd, Cu, and Ni concentrations were all higher than the required optimal health value in both groups. A high concentration of heavy metals was observed in these children that exceeded the value required for optimal health, although no significant difference in heavy metals with regards to secondhand smoking was observed. SHS was associated with children's ethnicity and parental marital status, but not with household income levels or maternal education.

Hyperspectral Prediction Model of Metal Content in Soil Based on the Genetic Ant Colony Algorithm

The accumulation of metals in soil harms human health through different channels. Therefore, it is very important to conduct fast and effective non-destructive prediction of metals in the soil. In this study, we investigate the characteristics of four metal contents, namely, Sb, Pb, Cr, and Co, in the soil of the Houzhai River Watershed in Guizhou Province, China, and establish the content prediction back propagation (BP) neural network and genetic-ant colony algorithm BP (GAACA-BP) neural network models based on hyperspectral data. Results reveal that the four metals in the soil have different degrees of accumulation in the study area, and the correlation between them is significant, indicating that their sources may be similar. The fitting effect and accuracy of the GAACA-BP model are greatly improved compared with those of the BP model. The R values are above 0.7, the MRE is reduced to between 6% and 15%, and the validation accuracy is increased by 12–64%. The prediction ability of the model of the four metals is Cr > Co > Sb > Pb. These results indicate the possibility of using hyperspectral techniques to predict metal content.

Inconsistent screening for lead endangers vulnerable children: policy lessons from South Bend and Saint Joseph County, Indiana, USA

Lead exposure is a major health hazard affecting children and their growth and is a concern in many urban areas around the world. One such city in the United States (US), South Bend Indiana, gained attention for its high levels of lead in blood and relatively low testing rates for children. We assessed current lead screening practices in South Bend and the surrounding St. Joseph County (SJC). The 2005-2015 lead screening data included 18,526 unique children. Lead screening rates ranged from 4.7 to 16.7%. More than 75% of children had 'elevated blood lead levels' (EBLL) ≥ 1 micrograms per deciliter (µg/Dl) and 9.7% had an EBLL ≥ 5 μg/dL. Over 65% of the census tracts in SJC had mean EBLL ≥ 5 μg/dL, suggesting widespread risk. Inconsistent lead screening rates, coupled with environmental and societal risk factors, put children in SJC at greater risk for harmful lead exposure than children living in states with provisions for universal screening. Indiana and other states should adhere to the US Centers for Disease Control's guideline and use universal lead testing to protect vulnerable populations.

Prevalence of Blood Lead among Children Living in Battery Recycling Communities in Greater Jakarta, Indonesia

This study aimed to assess the prevalence of blood lead levels (BLLs) among children 1 to 5 years old who reside near and distant to informally used lead-acid battery (ULAB) recycling locations and examine risk factors for elevated BLLs. A cross-sectional study was conducted in three greater Jakarta neighborhoods where informal ULAB recycling occurs. Venous BLLs among 279 children were analyzed using portable blood lead testing machines. Demographic, child activities, and sources of lead exposure inside and outside homes were assessed. Multivariate analysis was performed to evaluate factors associated with the prevalence of BLLs. Forty-seven percent of children had BLLs ≥ 5 µg/dL and 9% had BLLs ≥ 10 µg/dL. No differences in geometric mean BLLs were observed between children who lived near and distant to ULAB locations. Older child age groups [Prevalence Ratio (PR) 2.14, 95% Confidence Interval (CI) 1.16, 4.18) and low household income (PR 1.58, 95% CI 1.03, 2.40) were associated with BLLs 5-9 µg/dL. Low educational attainment of the child's father (PR 3.17, 95% CI 1.23, 8.16) and frequent outdoor child activity (PR 4.93, 95% CI 1.09, 22.21) were predictors of BLLs ≥ 10 µg/dL. This study shows the association between lead exposure among children and environmental sources. Public health officials can consider expanded surveillance, health care provider education, and development of strategies to reduce lead exposure.

Sources of lead exposure in various countries

This review evaluates the sources of lead exposure worldwide. Studies from searches relating to sources of lead exposure in various countries within different regional zones were reviewed. Results indicated that in Nigeria, exposure sources include electronic waste, paint and batteries. In Mexico exposure sources include glazed ceramics, lead contaminated utensils and lead contaminated water, for India lead sources include cosmetics and traditional medicines. Sources of lead exposure in China include e-waste, traditional medicines and industrial emissions. In France, exposure sources included lead paint from older homes, imported ceramics and cosmetics and industrial emissions. Australia's exposure sources include paint, dust, imported toys and traditional medicines. Finally, in the United States exposure sources included paint, the industrial legacy of lead exposure and batteries. In high-income countries (HICs) the legacy of lead exposure keeps populations continuously exposed. In lower- and middle-income countries (LMICs), in addition to the legacy of lead exposure, lack of regulations or the inability to enforce regulations keeps populations exposed. In all, evidence suggests that lead exposure remains an issue of public health significance in both HIC and LMIC.

Cholesterol and Oxidative Stress in U.S. Pregnant Women Exposed to Lead

Lead exposure among pregnant U.S. women was examined via the National Health and Nutrition Examination Survey (NHANES) 2009–2016 data to examine its role in bad cholesterol and oxidative stress. Mean values of the clinical markers non-high density lipoprotein cholesterol (non-HDL-c) and gamma-glutamyl transferase (GGT), a marker of oxidative stress, were explored. In four quartiles of lead exposure, clinical makers were compared. Binary logistic regression predicted the likelihood of elevated clinical markers in pregnant compared to non-pregnant women, while linear regression was used to examine associations between blood lead levels (BLL) and the clinical markers of interest. Mean non-HDL-c was statistically significantly more elevated in pregnant women than non-pregnant women. Mean GGT levels were more statistically significantly elevated in the highest quartile of BLL exposure among pregnant women than in the lower quartiles. In binary logistic regression models, pregnant women were statistically significantly more likely to have elevated non-HDL-c, while in linear regression BLL was statistically significantly associated with GGT levels in pregnant women. Lead exposure in pregnant women is an issue of public health concern that must continue to be studied.

Determinants of Erythrocyte Lead Levels in 454 Adults in Florence, Italy

Background: Lead exposure, even at low levels, is associated with adverse health effects in humans. We investigated the determinants of individual lead levels in a general population-based sample of adults from Florence, Italy. Methods: Erythrocyte lead levels were measured (using inductively coupled plasma-mass spectrometry) in 454 subjects enrolled in the Florence cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC) study in 1992⁻1998. Multiple linear regression models were used to study the association between demographics, education and working history, lifestyle, dietary habits, anthropometry, residential history, and (among women) menstrual and reproductive history and use of exogenous sex hormones, and erythrocyte lead levels. Results: Median lead levels were 86.1 μg/L (inter-quartile range 65.5⁻111.9 μg/L). Male gender, older age, cigarette smoking and number of pack-years, alcohol intake, and residing in urban areas were positively associated with higher erythrocyte lead levels, while performing professional/managerial or administrative work or being retired was inversely associated with lead levels. Among women, lead levels were higher for those already in menopause, and lower among those who ever used hormone replacement therapy. Conclusions: Avoidable risk factors contribute to the lead body burden among adults, which could therefore be lowered through targeted public health measures.

Interactive Effects between Chronic Lead Exposure and the Homeostatic Iron Regulator Transport HFE Polymorphism on the Human Red Blood Cell Mean Corpuscular Volume (MCV)

Research has shown that long-term exposure to lead harms the hematological system. The homeostatic iron regulator HFE (hemochromatosis) mutation, which has been shown to affect iron absorption and iron overload, is hypothesized to be related to lead intoxication in vulnerable individuals. The aim of our study was to investigate whether the HFE genotype modifies the blood lead levels that affect the distributions of serum iron and other red blood cell indices. Overall, 121 lead workers and 117 unexposed age-matched subjects were recruited for the study. The collected data included the blood lead levels, complete blood count, serum iron, total iron binding capacity, transferrin, and ferritin, which were measured during regular physical examinations. All subjects filled out questionnaires that included demographic information, medical history, and alcohol and tobacco consumption. HFE genotyping for C282Y and H63D was determined using polymerase chain reaction and restriction fragment length polymorphism (PCR/RFLP). The mean blood lead level in lead workers was 19.75 µg/dL and was 2.86 µg/dL in unexposed subjects. Of 238 subjects, 221 (92.9%) subjects were wild-type (CCHH) for HFE C282Y and H63D, and 17 (7.1%) subjects were heterozygous for a H63D mutation (CCHD). Multiple linear regression analysis showed that blood lead was significantly negatively associated with hemoglobin (Hb), mean corpuscular hemoglobin concentration (MCHC), and mean corpuscular volume (MCV), whereas the HFE variant was associated negatively with MCV and positively with ferritin. An interactive influence on MCV was identified between blood lead and HFE variants. Our research found a significant modifying effect of the HFE variant, which possibly affected MCV. The HFE H63D heterozygous (CCHD) variant seemed to provide a protective factor against lead toxicity. Future studies should focus on competing binding proteins between iron and lead influenced by gene variation.

Heavy Metals in Sediments of Urban Streams: Contamination and Health Risk Assessment of Influencing Factors

Sediments of two urban streams in northern Poland outflowing to the Baltic Sea were assessed to explain the spatial variation in relation to urbanization level of the catchment, the role of retention tanks (RTs) and identification of pollution level. During the 3 month period of investigation sediment samples were collected from the inflow (IN) and outflow (OUT) of six RTs located on streams for flood protection. Six heavy metals (HMs) were investigated: Cu, Pb, Zn, Cd, Ni, Cr. The assessment of four geochemical enrichment indices used to quantify contamination of HMs in the sediments at IN and OUT samples was carried out. Contamination factor (CF), pollution load index (PLI), geoaccumulation index (Igeo) and potential ecological risk (RI) were calculated and the indices usefulness was assessed. Also, the hazard quotient (HQ) was calculated to assess health risk associated with dredging works. In sediments from RTs where paved surfaces constituted more than 70% of the catchment the HMs concentrations were from one to three times higher for Ni and from two to 143 times higher for Cu in comparison to soft catchment results. The extremely high Cu concentration (1114 mg/kg d.w.) found in sediments at RT Orłowska IN was most likely associated with large area of roofs covered with copper sheet. Calculation of CF, PLI, Igeo, RI, HQ indicators allows for a complex and multi-dimensional assessment of sediment status. Among these, CF and PLI classified the analyzed sediments as most polluted. Basing on the sedimentary HMs concentrations the health risk level via dermal exposure pathway was assessed as low.

Efficiency of the Air-Pollution Control System of a Lead-Acid-Battery Recycling Industry

The air-pollution control system of a lead-acid-battery recycling industry was studied. The system comprised two streams with gravity settlers followed by filter bags for the factory indoor air and the metal-recycling furnace, respectively. Efficiency in particle removal according to mass was found to be 99.91%. Moreover, filter bags and dust from the gravity settlers were analyzed for heavy metals by Wavelength Dispersive X-Ray Fluorescence. The results showed high concentrations of Pb and Na in all cases. In the filter bag samples from the indoor atmosphere stream, Ca, Cu, Fe, and Al were found in concentrations higher than that in the filter bag samples from the furnace stream. The opposite was found for Na. Tl and K were only found in furnace stream bag filters. The elemental concentration of the dust from the furnace fumes stream contained mainly Fe, Na, Cd, Pb, Sb, and Cl, while the indoor main stream contained mainly P, Fe, Na, Pb, and Sb. In all cases, impurities of Nd, Ni, Rb, Sr, Th, Hg, and Bi were found. The high efficiency of the air-pollution control system in particle removal shows that a considerable reduction in emissions was achieved.

Blood Pressure and Oxidative Stress among U.S. Adults Exposed to Lead in Military Environments-A Preliminary Study

In this cross-sectional study, lead exposure among those with a history in military environments was examined. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) are clinical markers of blood pressure, while gamma-glutamyl transferase (GGT) is a marker of oxidative stress. These markers and their effects on those exposed to military environments were explored using National Health and Nutrition Examination Survey (NHANES) data from 2009 to 2016. Mean SBP and GGT were significantly elevated in those exposed to military environments, with a moderately significant association existing between blood lead levels (BLLs) and SBP. More attention must be given to lead exposure in military environments to mitigate the risk of exposure.

Lead Exposure and Oxidative Stress-A Life Course Approach in U.S. Adults

Lead exposure and a marker of oxidative stress (gamma-glutamyl transferase—GGT), and their effects on life course variables (age, country of birth, education levels, gender, ethnicity, income, and occupation) were explored in this cross-sectional study of United States (U.S.) adults’ ≥ 20 years of age via the National Health and Nutrition Examination Survey (NHANES) 2007–2010 datasets. Country of birth, education levels, gender, ethnicity, income, and occupation showed significant differences depending on the degree of lead exposure, with higher levels of exposure resulting in worse outcomes. Age and GGT were significantly associated with lead exposure. More must be done to mitigate sources of lead exposure, to prevent it from altering the life course of at-risk populations.

Mapping the Urban Lead Exposome: A Detailed Analysis of Soil Metal Concentrations at the Household Scale Using Citizen Science

An ambitious citizen science effort in the city of Indianapolis (IN, USA) led to the collection and analysis of a large number of samples at the property scale, facilitating the analysis of differences in soil metal concentrations as a function of property location (i.e., dripline, yard, and street) and location within the city. This effort indicated that dripline soils had substantially higher values of lead and zinc than other soil locations on a given property, and this pattern was heightened in properties nearer the urban core. Soil lead values typically exceeded the levels deemed safe for children's play areas in the United States (<400 ppm), and almost always exceeded safe gardening guidelines (<200 ppm). As a whole, this study identified locations within properties and cities that exhibited the highest exposure risk to children, and also exhibited the power of citizen science to produce data at a spatial scale (i.e., within a property boundary), which is usually impossible to feasibly collect in a typical research study.

Is There a Relationship between Lead Exposure and Aggressive Behavior in Shooters?

Lead exposure has been associated with psycho-neurological disorders. Elevated blood lead levels have been found in shooters. This study assesses the association between the blood lead levels of shooters and their levels of aggression. An analytical cross-sectional study was conducted in Gauteng, South Africa. Participants were recruited from four randomly selected shooting ranges with three randomly selected archery ranges used as a comparison group. A total of 118 (87 shooters and 31 archers) participants were included in the analysis. Aggressiveness was measured using the Buss-Perry Aggression Questionnaire. Shooters had significantly higher blood lead levels (BLL) compared to archers with 79.8% of shooters versus 22.6% of archers found to have a BLL ≥ 5 μg/dL (p < 0.001). Aggression scores were significantly higher in shooters (p < 0.05) except for verbal aggression. In the bivariate and regression analyses, shooters with BLLs ≥ 10 μg/dL were significantly associated with the hostility sub-scale (p = 0.03, adjusted odds ratio (OR) 2.83, 95% confidence interval (CI) 1.103–7.261). Shooters have a significantly higher BLL and aggressiveness compared to archers. However, elevated blood lead levels were significantly associated with hostility only. Interventions need to be put in place to prevent continued exposure and routine screening of populations at risk should be implemented.

Cardiovascular-Related Outcomes in U.S. Adults Exposed to Lead

Cardiovascular-related clinical markers were evaluated in this cross-sectional study of United States adults (aged ≥ 20) exposed to lead via the National Health and Nutrition Examination Survey 2007-2008 and the 2009-2010 datasets. In four quartiles of exposure-0-2 μg/dL, 2-5 μg/dL, 5-10 μg/dL, and 10 μg/dL and over, clinical and anthropometric markers were evaluated-to examine how the markers manifested in the quartiles. Associations were determined via linear regression. Finally, clinical makers, and how they manifested between exposed and less-exposed occupations, were explored in addition to how duration of exposure altered these clinical markers. In regression analysis, Diastolic Blood Pressure (DBP) and high-density lipoprotein (HDL) cholesterol, were significantly associated with blood lead level (BLL). In the occupational analysis, Systolic Blood Pressure (SBP), DBP, C-reactive protein (CRP), triglycerides, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, showed differences between populations in the exposed and less-exposed occupations. Regarding Agriculture, Forestry & Fishing, the duration of exposure altered SBP, CRP, and LDL cholesterol. With mining, the duration of exposure altered SBP, DBP, triglycerides, and HDL cholesterol, whereas in construction, the duration in occupation altered SBP, triglycerides, and CRP. In conclusion, lead exposure has a profound effect on the cardiovascular system, with potentially adverse outcomes existing at all exposure levels.