Recommendations for medical management of adult lead exposure

Co-administration of resveratrol rescued lead-induced toxicity in Drosophila melanogaster

Lead toxicity poses a significant environmental concern linked to diverse health issues. This study explores the potential mitigating effects of resveratrol on lead-induced toxicity in Drosophila melanogaster. Adult fruit flies, aged three days, were orally exposed to lead (60 mg/L), Succimer (10 mg), and varying concentrations of resveratrol (50, 100, and 150 mg). The investigation encompassed the assessment of selected biological parameters, biochemical markers, oxidative stress indicators, and antioxidant enzymes. Resveratrol exhibited a dose-dependent enhancement of egg-laying, eclosion rate, filial generation output, locomotor activity, and life span in D. melanogaster, significantly to 150 mg of diet. Most of the investigated biochemical parameters were significantly rescued in lead-exposed fruit flies when co-treated with resveratrol (p < 0.05). However, oxidative stress remained unaffected by resveratrol. The findings suggest that resveratrol effectively protects against lead toxicity in Drosophila melanogaster and may hold therapeutic potential as an agent for managing lead poisoning in humans.

Low-level, chronic ingestion of lead and cadmium: The unspoken danger for at-risk populations

The long-term effects of low-level, chronic exposure to lead and cadmium through ingestion are often overlooked, despite the urgency surrounding the clinical onset and worsening of certain pathologies caused by these metals. This work reviews current legislation, global ingestion levels, and blood levels in the general population to emphasize the need for reactivity towards this exposure, especially in at-risk populations, including patients with early-stage renal and chronic kidney disease. Global data indicates persistent chronic ingestion of lead and cadmium, with no decreasing trend in recent years, and a daily consumption of tens of micrograms worldwide. Moreover, the average blood lead and cadmium levels in the general population are concerning in many countries with some significantly exceeding healthy limits, particularly for children. Technologies developed to cleanse soil and prevent heavy metal contamination in food are not yet applicable on a global scale and remain financially inaccessible for many communities. Addressing this chronic ingestion at the human level may prove more beneficial in delaying the onset of associated clinical pathologies or preventing them all together.

Probing the opto-electronic, phonon spectrum, and thermoelectric properties of lead-free fluoride perovskites A2GeSnF6 (A = K, Rb, Cs) for energy harvesting devices

The present work employs density functional theory to explore the structural, optoelectronic, and thermoelectric attributes of the halide-based double perovskite A2GeSnF6 (A = K, Rb, and Cs) compounds. The stable phonon dispersion spectrum affirms dynamical stability, whereas the enthalpy of formation and tolerance factor evaluated collectively verify structural stability. Considering the Tran Blaha modified Becke Johnson potentials (mBJ), the predicted direct band gaps along the symmetry point are 3.19 eV for K2GeSnF6, 3.16 eV for Rb2GeSnF6 and 3.12 eV Cs2GeSnF6. According to an in-depth examination of the optoelectronic features, A2GeSnF6 (A = K, Rb, and Cs), double perovskites are assuring contenders for optoelectronic devices due to their suitable bandgap. The extremely high figure of merit values (0.94-0.97) obtained from the numerical calculation of power factor and thermal conductivity suggest the intriguing prospects of these compositions for thermoelectric devices. These studies offer a perceptive comprehension of the materials for their potential applications in the future.

Trends in Shortages of Lead Chelators From 2001 to 2022

OBJECTIVE

The study aims to describe drug shortages affecting lead chelators in the United States from 2001 through 2022.

METHODS

Drug shortage data were retrieved from the University of Utah Drug Information Service from January 1, 2001, through December 31, 2022. Shortages of first- and second-line lead chelators were analyzed. Drug class, formulation, administration route, shortage reason, shortage duration, generic status, single-source status, and presence of temporally overlapping shortages were examined. Total shortage months, percentages of study period on shortage, and median shortage durations were calculated.

RESULTS

Thirteen lead chelator shortages were reported during the study period. Median duration was 7.4 months and the longest shortage (24.8 months) involved calcium disodium edetate. Calcium disodium edetate and dimercaprol had the greatest number of shortages, 4 each, and 61.5% of shortages involved parenteral medications. Median shortage duration was 14.2 months for parenteral agents and 2.2 months for non-parenteral agents. All shortages involved generic, single-source products. Supply/demand and manufacturing problems were the most common shortage reasons provided. Overlapping shortages occurred for 3.7% of the study period. Median shortage duration increased from 3 to 11 months in the second half of the study period, and 61.5% of shortages occurred in the second half of the study period.

CONCLUSIONS

All chelators experienced multiple shortages, which became increasingly frequent and prolonged over time. Concurrent shortages occurred, potentially hampering substitution between different agents. Health care stakeholders must build supply chain resilience and develop guidelines regarding how to modify chelation therapy based on shortage conditions.

Outbreak of lead poisoning from a civilian indoor firing range in the UK

INTRODUCTION

Lead exposure from discharged lead dust is a recognised risk at firing ranges. We report a lead poisoning outbreak among staff and their close contacts at a UK civilian indoor 24 m firing range.

METHODS

A retrospective review was undertaken of data collected on all patients at risk of lead poisoning identified either by direct referral to the Clinical Toxicology clinicians at the West Midlands Poisons Unit, or via the Trace Elements Supra-Regional Assay Service Laboratory at Sandwell hospital.

RESULTS

Eighty-seven patients were identified as having possible lead exposure, either at the firing range or via close contacts. Of these, 63 patients aged between 6 months and 78 years attended for blood lead concentration (BLC) testing. The highest BLC at presentation was 11.7 µmol/L (242 µg/dL). Only nine patients reported any symptoms at presentation. Fifteen patients received lead chelation therapy with oral dimercaptosuccinic acid (or succimer) 30 mg/kg/day or intravenous sodium calcium edetate (EDTA) 75 mg/kg/day, dependent on stock availability.

DISCUSSION

This report highlights the need for vigilance of lead poisoning as an occupational hazard in the UK, including at recreational facilities such as indoor firing ranges. It emphasises the importance of regulation of lead exposure in the workplace, particularly given the vague symptoms of lead poisoning, and proposes re-appraisal of UK legislation. This report also highlights potential issues surrounding stock availability of rarely used antidotes for uncommon presentations in the event of an outbreak of poisoning.

Quantification of toxic heavy metals, trace elements and essential minerals contents in traditional herbal medicines commonly utilized in Khyber Pakhtunkhwa, Pakistan

Traditional herbal medicines and health supplements have been empirically used to treat various disorders but most of them are not standardized and have not been experimentally validated for safety and efficacy. In the present study, various dosage forms of traditional herbal medicines prescribed for specific diseases were collected from local practitioners at different districts of Khyber Pakhtunkhwa, Pakistan. The collected samples were analyzed for heavy metal, trace elements, and minerals using atomic absorption spectroscopy. All the tested samples contained heavy metals, trace elements and minerals in different concentrations. All the samples were tested positive for the presence of toxic heavy metals such as arsenic (As), cadmium (Cd) and lead (Pb). The trace elements like cobalt (Co), iron (Fe), zinc (Zn) and chromium (Cr) were also detected in acceptable range. Similarly, the samples analyzed were rich in some of the essential minerals such as sodium (Na), magnesium (Mg) and calcium (Ca) which are necessary for the proper functioning of the body. The hazard quotient (HQ) values were measured for toxic heavy metals to determine their safe ranges for human body. The HQ values were above the permissible range for arsenic (As) in all detected samples while for cadmium (Cd) and lead (Pb), the values ware above in 50 % of the analyzed samples. The detection of toxic metals and their HQ values beyond the permissible limits in different dosage forms raised questions about their quality. This study suggests that evaluation of traditional herbal remedies for the metals contents and their standardization are strongly recommended for quality assurance and protection of public health.

Effects of the Decrease in Blood Lead Levels on Renal and Neurological Functions Among Occupationally Exposed and Unexposed Populations of South India: A Cohort Study

INTRODUCTION

Exposure to lead in excess of the permissible limit is a known risk factor leading to preventable morbidity. The present study aimed to assess whether there is a change in the neurological and renal parameters among adults with blood lead levels (BLLs) higher than recommended at baseline and after prevention among differently exposed adults.

METHODOLOGY

In the Guntur District of Andhra Pradesh, India, a cohort study was carried out in 2022-2023 among 180 adult males and females aged 20 to 60 years in three groups: direct occupational exposure, indirect occupational exposure, and no occupational exposure. If the blood levels were more than or equal to 5 mcg/dL, the participant's detailed neurological examination was done at baseline and end of follow-up. During the six-month follow-up period, health education on lead awareness was given monthly. BLLs were estimated using graphite furnace atomic absorption spectrometry (GFAAS). Serum creatinine was estimated using Jaffe's modified method. On neurological examination, reflexes, power, and sensation were assessed. The vibration perception threshold was determined using a biothesiometer. A p-value less than 0.05 was considered to be statistically significant.

RESULTS

Among the 180 participants, the mean BLLs at baseline were 7.15±3.06 mcg/dL. The findings revealed a statistically significant decrease in mean BLLs at baseline to end of six-month follow-up. Despite this improvement, participants with BLLs ≥5 mcg/dL still accounted for a considerable proportion, albeit reduced, particularly in Groups 1 and 2. There were no statistically significant changes observed in the proportions of participants with abnormal serum creatinine, anemia, or abnormal neurological parameters.

CONCLUSION

These results suggest that while prevention activities may effectively reduce overall BLLs, there might be challenges in completely mitigating the impact on certain health parameters, such as renal and neurological functions.

Unmasking herbal medication-induced lead poisoning in a geriatric patient with gastrointestinal symptoms

Lead poisoning, often associated with occupational exposure, can also arise from intake of traditional and herbal medicines with high lead content. Geriatric patients displaying gastrointestinal symptoms from such sources are frequently misdiagnosed. An individual in his 70s reported to our geriatric clinic with vomiting, constipation and anaemia. A meticulous history unveiled his recent intake of herbal remedies. Heavy metal assay indicated elevated lead levels in his blood and urine, consistent with the high lead content we measured in the herbal medication. Following supportive treatment, nutritional supplementation and chelation therapy with calcium disodium EDTA, he improved. Follow-up tests indicated a decrease in lead levels and resolution of anaemia. This case emphasises the importance of considering lead poisoning as a potential diagnosis in patients with unexplained symptoms, particularly when there is a history of herbal or alternative medication intake. Timely recognition and appropriate management can lead to better outcome.

Inflammatory low back pain with radiculopathy revealing epidural disintegration of a bullet complicated by lead poisoning

Inflammatory low back pain with radiculopathy is suggestive of cancer, infection or inflammatory diseases. We report a unique case of a 42-year-old patient with an acute inflammatory low back pain with bilateral radiculopathy associated with weight loss and abdominal pain, revealing the disintegration of a lead bullet along the epidural space and the S1 nerve root complicated by lead poisoning. Because of the high blood lead level of intoxication (>10 times over the usual lead levels) and the failure of repeated lead chelator cycles, a surgical treatment to remove bullet fragments was performed. It resulted in a significant decrease of pain and lead intoxication.

Succimer chelation does not produce lasting reductions of blood lead levels in a rodent model of retained lead fragments

Retained lead fragments from nonfatal firearm injuries pose a risk of lead poisoning. While chelation is well-established as a lead poisoning treatment, it remains unclear whether chelation mobilizes lead from embedded lead fragments. Here, we tested whether 1) DMSA/succimer or CaNa2EDTA increases mobilization of lead from fragments in vitro, and 2) succimer is efficacious in chelating fragment lead in vivo, using stable lead isotope tracer methods in a rodent model of embedded fragments. DMSA was > 10-times more effective than CaNa2EDTA in mobilizing fragment lead in vitro. In the rodent model, succimer chelation on day 1 produced the greatest blood lead reductions, and fragment lead was not mobilized into blood. However, with continued chelation and over 3-weeks post-chelation, blood lead levels rebounded with mobilization of lead from the fragments. These findings suggest prolonged chelation will increase fragment lead mobilization post-chelation, supporting the need for long-term surveillance in patients with retained fragments.

Rare causes of abdominal pain: a primer for the admitting general surgeon

The broad uptake of the acute surgical unit (ASU) model of surgical care in Australia has resulted in general surgeons becoming increasingly involved in the management of patients with acute abdominal pain (AAP), some of whom will be labelled as having non-specific abdominal pain (NSAP) (Kinnear N, Jolly S, Herath M, et al. The acute surgical unit: An updated systematic review and meta-analysis. review. Int. J. Surg. 2021;94:106109; Lehane CW, Jootun RN, Bennett M, Wong S, Truskett P. Does an acute care surgical model improve the management and outcome of acute cholecystitis? ANZ J. Surg. 2010;80:438-42). NSAP patients lack a clear diagnosis of surgical pathology based on standard clinical, laboratory and imaging work-up, although they may require ASU admission for pain control and assessment. This article provides a review of uncommon conditions, presenting as AAP, that could possibly be mis-labelled as NSAP, with a focus on aspects of the presentation that may aid diagnosis and management including specific demographic features, clinical findings, key investigations and initial treatment priorities for ASU clinicians. Ultimately, most of the conditions discussed will not require surgical intervention, however, they require a diagnosis to be made and initial treatment planning before on-referral to the appropriate specialty. For the on-call general surgeon, some knowledge of these conditions and an index of suspicion are invaluable for the prompt diagnosis and efficient management of these patients.

Evaluation and updates to the Leggett model for pharmacokinetic modeling of exposure to lead in the workplace - Part II adjustments to the adult exposure model, confirmation of Leggett+, and modeling of workplace exposure

California's Office of Environmental Health Hazard Assessment has updated the comprehensive age-specific model of lead metabolism in humans published by Richard W. Leggett in 1993. The updated model, called Leggett+, was introduced in a peer-reviewed report in 2013. The Leggett + model simulates the relationship between blood lead and exposure in the workplace. Leggett + includes a workplace exposure model comprising respiratory tract intake (workplace lead inhaled by a worker) and uptake (lead absorbed into the blood from the respiratory tract plus uptake from ambient air and diet). The latter is calculated as intake times an inhalation transfer coefficient plus background uptake. An adjusted adult systemic model describes the metabolism of the absorbed lead. This paper provides details about the workplace exposure and uptake elements of Leggett+, an updated approach to calibrating an inhalation transfer coefficient, confirmation of the model's performance in predicting blood lead levels from workplace studies, and predictions of blood lead levels from simulated exposures to workplace airborne lead over a working lifetime. Blood lead relative to airborne lead concentrations in a standard workplace scenario predicted by Leggett + was similar to corresponding relationships from four published workplace studies. Leggett + predictions displayed a good fit to regression equations when other key factors were considered such as pre-employment blood lead and ongoing background intake of lead, workplace air concentration, lead aerosol characteristics, and worker activity levels. The comprehensive Leggett + model can simulate plausible workplace air-blood lead relationships from a broad range of worker exposures. The inhalation transfer coefficient of 0.30, derived from empirical data described in the 2013 report has been reexamined. The original estimate continues to represent a plausible mid-point for a coefficient derived from an expanded range of theoretical particle size distributions deposited in the upper and lower regions of the respiratory tract considering intake during sedentary and outdoor activity breathing scenarios. This coefficient is slightly lower than the value of 0.35 estimated for unknown forms of lead by Leggett in 1993.

Investigation and monitoring of heavy metal poisoning

Historically, heavy metal measurement and interpretation has been a highly specialised area performed only in a handful of centres within the UK. However, recent years have seen a move to more local testing due to the repatriation of referred work into pathology networks and the increased availability of inductively coupled plasma mass spectrometry technology. While management of significant poisoning is still overseen by tertiary care poisoning specialists, management of milder cases may be undertaken locally.Non-specialist clinical scientists and clinicians need to know when heavy metal testing is appropriate, which samples are required (and any specific requirements around collection) and how to interpret and act on the results.This Best Practice article provides guidance on the investigation and monitoring of the toxic elements most frequently encountered in general medical practice; lead, mercury and arsenic. It is intended as a reference guide for the non-specialist and as a comprehensive summary for clinical toxicologists and clinical scientists.

Exposure Sources Among Veterans With Elevated Blood Lead Levels, United States, 2015‒2021

Objectives. To determine characteristics and sources of exposure in veterans with elevated blood lead levels (BLLs). Methods. We included users of US Veterans Health Administration care aged 18 years or older tested for BLL from October 2015 to September 2021. Prevalence of BLL 10 micrograms per deciliter (µg/dL) or higher and 25 µg/dL or higher was determined within demographic groups. Logistic regression analysis measured association of International Classification of Diseases, Tenth Revision, Clinical Modification‒coded conditions with elevated BLL. Electronic notes were reviewed for exposure sources. Results. Among 1007 unique veterans with BLL 10 µg/dL or higher, prevalence of BLL 10 µg/dL or higher and 25 µg/dL or higher peaked at 4.9 and 1.3 per 100 000 veterans, respectively (fiscal year 2019), and was highest in non-Hispanic White men and those aged 25 to 34 years. Conditions predicted by elevated BLL were attention-deficit/hyperactivity disorder (ADHD) and nausea or vomiting. Firearms represented 70.1% of occupational and 85.9% of nonoccupational exposures. Toxicology consults occurred in 17 of 298 (6%) with BLL 25 µg/dL or higher. Conclusions. Firearms were the largest exposure source among veterans with elevated BLL. Clinicians should be alert for potential conditions (including ADHD and nausea or vomiting in our study) associated with lead exposure. Standardization of care regarding toxicology referral practices is warranted. (Am J Public Health. 2022;112(S7):S670-S678. https://doi.org/10.2105/AJPH.2022.306936).

Health Remedies as a Source of Lead, Mercury, and Arsenic Exposure, New York City, 2010-2019

Objectives. To describe the types of health remedies collected during poisoning investigations in New York City over a 10-year period that were found to contain high levels of lead, mercury, or arsenic. Methods. Between 2010 and 2019, the New York City Department of Health and Mental Hygiene collected 584 samples of health remedies during poisoning investigations and store surveys for lead, mercury, or arsenic analysis. Results. There was a significant association between blood lead levels and estimated cumulative daily lead exposures among adult users of rasa shastra Ayurvedic medications. Also, average blood lead levels among adult rasa shastra users were significantly higher than levels among those using other types of non-Ayurvedic health remedies. Conclusions. Rasa shastra Ayurvedic medications can contain very high levels of lead, mercury, and arsenic. This underscores the importance of screening for lead, mercury, and arsenic exposures within at-risk populations. Public Health Implications. The general ease of accessibility to rasa shastra medications raises concerns. There is a need for systemic change that results in primary prevention, that is, removal of the source through policy development and regulatory enforcement in the country of origin. (Am J Public Health. 2022;112(S7):S730-S740. https://doi.org/10.2105/AJPH.2022.306906).

Trends of Blood Lead Levels in US Pregnant Women: The National Health and Nutrition Examination Survey (2001–2018)

Objectives

This study investigates the trends of blood lead levels in US pregnant women based on the National Health and Nutrition Examination Survey from 2001 to 2018.

Methods

A total of 1,230 pregnant women were included in this study. The weighted logistic regression was applied to analyze the association between sociodemographic characteristics with high blood levels. We computed the blood lead levels for each survey period from 2001–2002 to 2017–2018. Moreover, we used the adjusted linear regression model to investigate the time-related change in blood lead level. The odds ratio (OR) with a 95% confidence interval (CI) was calculated accordingly.

Results

The mean blood lead was 0.73 ± 0.03 ug/dL, and high blood lead was observed in 2.53% of individuals. The Mexican Americans were more associated with high blood lead than the non-Hispanic white (OR, 1.072; 95% CI, 1.032-1.112). The mean blood lead level has decreased from 0.97 ug/dL in 2001–2002 to 0.46 ug/dL in 2013–2014. Afterward, a slight increase was observed with the mean blood lead of 0.55 ug/dL in 2015–2016 and 0.53 ug/dL in 2017-2018. In the adjusted linear regression model, each year's increase would lead to a 0.029 ug/dL decrease in blood lead (P < 0.001). However, no significant change was observed in the 2017–2018 cycle compared with 2009–2010 (P = 0.218).

Conclusion

This study summarized the trend of blood lead levels in US pregnant women over 2001–2018. Continued effort is still required to control lead sources better and protect this population from lead exposure.

A Comparative Health Assessment of Occupationally Lead Exposed Individuals with Blood Lead Levels Range across Upper Acceptable Limit

CONTEXT

Lead (Pb) smelting workers are exposed to high lead levels and its adverse health effects. Despite no biological role, regulatory bodies regard blood lead levels (BLL) ≤40 µg/dL as upper acceptable limit in occupationally lead exposed population.

OBJECTIVE

To explore the differences in general health status of individuals with BLL ≤40 µg/dL and >40 µg/dL.

METHODS

All workers (n = 803) of age >18 years employed in a Pb smelting plant were interviewed with a semi-structured questionnaire to obtain sociodemographics, occupational details, followed by detailed clinical examination. 5 ml of venous blood was collected and BLLs were determined as per standard NIOSH method using GF-AAS technic. A complete general health status was performed including hemoglobin and blood pressure (BP).

RESULTS

About 47.7% of the participants exhibited high BLL (>40 µg/dL), while the rest 52.3% were identified to have ≤40 µg/dL. Both groups were grossly similar in the majority of demographic and occupational parameters. Interestingly, both groups had substantially higher fraction of workers with elevated BP.

CONCLUSIONS

Lead exposed workers with BLL ≤40 µg/dL are at equal risk of health hazards as those with BLL >40 µg/dL. There is a need to revisit the current guidelines on the BLL for workers to protect from the hazards of chronic lead exposure.

Lead poisoning among asymptomatic individuals with a long-term history of opiate use in Golestan Cohort Study

BACKGROUND

Recent reports of lead poisoning suggest that people who use opium may be exposed to high amounts of lead. Here, we investigate the association between opium use and blood lead levels (BLL) in a population-based cohort study.

METHODS

In 2017, we studied a random sample of 410 people who currently (both within the past year and the past month) used opium and 104 who did not from participants of the Golestan Cohort Study in northeast Iran. Participants were stratified by sex and tobacco use history, completed a comprehensive opiate and tobacco use questionnaire and provided blood. BLL was measured by Lead Care® II Blood Lead Test Kit, validated by inductively coupled plasma triple quadrupole mass spectrometry. BLL was categorized as "<5 µg/dL", "elevated" (5-10 µg/dL), "high" (10-50 µg/dL), and "very high" (above 50 µg/dL). To assess the association between BLL categories and opiate use, route of consumption and weekly use, we used ordered logistic regression models, and report OR (odds ratio) and 95% CI (confidence interval) adjusted for age, sex, place of residence, education, occupation, household fuel type, and tobacco use.

RESULTS

In the cohort, participants used only raw (teriak) or refined (shireh) opium, which were smoked (45%, n = 184), taken orally (46%, n = 189), or both (9%, n = 37), for a mean duration of 24.2 (standard deviation: 11.6) years. The median BLL was significantly higher in people who currently used opium (11.4 µg/dL; IQR: 5.2-23.4) compared with those who did not (2.3 µg/dL; IQR: 2.3-4.2), and the highest median BLL was seen in oral use (21.7 µg/dL; IQR: 12.1-34.1). The BLL was <5 µg/dL among 79.8% of people with no opiate use, compared with only 22.7% in those using opium. BLL was elevated in 21.7%, high in 50.5% and very high in 5.1% of people using opium. About 95% of those with oral (180/189) or dual use (35/37) and 55% (102/184) of those who smoked opium had levels of blood lead above 5 µg/dL. The OR for the association between any opium use and each unit of increase in BLL category was 10.5 (95%CI: 5.8-19.1), and oral use of opium was a very strong predictor of increasing BLL category (OR=74.1; 95%CI: 35.1-156.3). This odds ratio was 38.8 (95%CI: 15.9-95.1) for dual use and 4.9 (95%CI: 2.6-9.1) for opium smoking. There was an independent dose-response association between average weekly dose and BLL among people using opium, overall and when stratified by route of use.

CONCLUSION

Our results indicate that regular use of lead-adulterated opium can expose individuals to high levels of lead, which may contribute to mortality and cancer risks associated with long-term opium use.

Two cases of lead poisoning associated with occupational exposure presented as intestinal obstruction: a case report

Lead exposure in India is common in industries that may present with nonspecific signs and symptoms or symptoms of toxicity, depending on the amount of lead absorbed. We are presenting two case reports of occupational lead exposure in a lead-based battery manufacturing unit, which were presented as intestinal obstruction. Both the patients aged 28 and 24-year old presented with complaints of pain in the abdomen with blood lead levels of 61.1 and 85 μg/dl, respectively. The diagnosis was made clinically before any other radiological investigation or intervention. Both the patients were treated conservatively with D-Penicillamine, following which, both the patients improved symptomatically and the blood lead level also decreased. The importance of a detailed history of occupation & clinically diagnosing such patient will avoid unnecessary investigation and intervention. This will help to reach the correct diagnosis in such cases.

A preliminary study on health impacts of Mexican mercury mining workers in a context of precarious employment

Mercury mining is one of the main sources of mercury (Hg) release into the environment, causing serious impacts on human health and the environment. Workers in these mines are employed informally and precariously and therefore lack labor rights such as social security. The objective of the study is to make visible the exposure to environmental contaminants and the health of workers in mercury mines. An environmental assessment was conducted to determine workers' exposure to contaminants; urine samples were obtained to measure exposure to mercury and arsenic, and blood samples were obtained for lead and cadmium. Clinical parameters were also evaluated. Concentrations of Hg, As and Pb were determined in soil, 279.4 mg/kg (24.4-788.5), 14.7 mg/kg (9.5-20.3) and 1.4 mg/kg (1-2.8), respectively. The exposure results for mercury were 551 μg/g creatinine, for arsenic 50 μg/L and for lead 4.7 μg/dL. Cd-B was not found. In addition, 17.6 % of the workers had diabetes and 17.6 % had renal disorders. Principal Component Regression was performed obtaining an r2 of 0.86 for glomerular filtration rate and 0.54 for albumin creatinine ratio using clinical, occupational, and metal exposure variables. Exposure to Hg in this type of mine is not exclusive, so there is a cumulative risk of chronic exposure to different environmental pollutants directly impacting the health of workers. It is necessary to implement health strategies and different work opportunities for these workers.

[Severe lead poisoning caused by ayurvedic medicine]

HISTORY

 We report the case of a young patient who presented to our emergency department with reduced general condition, anemia, and crampy abdominal pain. A previous inpatient workup including abdominal imaging and bone marrow aspiration had not yielded a diagnosis. On inquiry, the patient reported oral ingestion of an Ayurvedic remedy over the course of one month.

FINDINGS

 24-year-old circulatory stable patient in reduced general condition with gray skin coloration and a dark gingival margin. Laboratory testing revealed an increase in transaminases and normocytic anemia. A peripheral blood smear showed basophilic stippling of the erythrocytes. Significantly elevated lead levels were detected in the patient's blood and hair. Toxic lead levels were detected in the ingested preparation.

DIAGNOSIS

 Severe lead poisoning caused by self-medication with an Ayurvedic remedy. Analysis revealed a daily oral lead load of 136 times the maximum permissible dose.

THERAPY AND COURSE

 By means of chelation therapy, the blood lead levels were significantly reduced, and there was a complete regression of the complaints as well as a normalization of the laboratory findings.

CONCLUSION

 Lead has toxic effects on all organ systems of the body and is stored in the bone for decades. Symptoms of poisoning are nonspecific; a thorough history and generous indication for measuring lead levels are helpful for the diagnosis.

Basophilic stippling in red blood cells in the bone marrow: indication for lead poisoning diagnosis

A 40-year-old man presented at our hospital with anaemia that had been undiagnosed for 2 years. Blood tests, endoscopy, and contrast-enhanced computed tomography were performed, but a definitive diagnosis could not be made. A subsequent bone marrow biopsy revealed basophilic stippling in transformed red blood cells, which led to a differential diagnosis of lead poisoning. Additional tests revealed elevated levels of lead in the blood. Basophilic stippling is generally found on a peripheral blood smear in lead poisoning patients; however, in this case, basophilic stippling was found only on the bone marrow smear and not in the blood smear. Even if basophilic stippling is not found in the peripheral blood, lead poisoning cannot be excluded.

Case series of chronic occupational lead exposure in shooting ranges

INTRODUCTION

Despite existing occupational lead exposure prevention regulations, Lithuanian shooting range workers still complain of chronic lead poisoning related symptoms. This indicates a poor understanding of occupational safety when working in lead-polluted environments.

CASE PRESENTATION

20 men, whose age ranged from 32 to 57 (mean 41.8 ± 10 years), were consulted at the Toxicology Centre at the Republican Vilnius university hospital in Vilnius, Lithuania in the 2016-2019 year period. All of the patients were working as shooting instructors, with their work experience varying from 2 to 30 years. Clinical examination showed blood lead levels ranging from 5.64 μg/dL to 45.8 μg/dL (norm for occupational exposure - <40 μg/dL). Main symptoms were fatigue (12 patients out of 20), dizziness (5/20), arthralgia (5/20). Other symptoms included impaired memory (3/20), nausea (3/20), sleep disorders (3/20), metallic or sweet taste (3/20), dermatological disorders (3/20), coxarthrosis (2/20), balance disorders (2/20), paresthesia (2/20), abdominal pain (2/20) and others. 4 patients were asymptomatic.

DISCUSSION

Shooting range employees are highly vulnerable to daily lead exposure. Even low constant elevated blood lead concentrations can have significant toxic effects over time.

Prevalence of metal levels above the reference values in a municipality affected by the collapse of a mining tailings dam: Brumadinho Health Project

ABSTRACT Objective: To describe the prevalence of levels of arsenic, cadmium, mercury, lead and manganese above the reference values (RV) in the population of Brumadinho, after the rupture of the mining tailings dam and to verify the factors associated with these levels. Methods: Baseline study of a prospective cohort, in a representative sample of 3,080 residents (aged 12 and over) in Brumadinho, Minas Gerais. Exploratory variables (age, sex, skin color, household income, smoking and place of residence) were collected using a questionnaire and the levels of As, Cd and Hg in urine and Pb and Mn in blood were evaluated using the technique of inductively coupled plasma mass spectrometry. The distribution of prevalence of levels above the reference for metals was made, according to the exploratory variables. Multiple logistic regression analyzes were used to investigate the association between altered levels of metals and characteristics evaluated. Results: Concentrations above RV were found in 38.08% of the population for Mn, 33.37% for As, 5.04% for Pb, 0.76% for Hg and 0.17% for Cd. There was a significant association between age group and levels of Mn and Pb; and between place of residence and As level. Conclusion: The results show a high prevalence of levels above the reference for Mn, As and Pb, with small differences in relation to the other variables, suggesting that it is an exposure distributed throughout the municipality.

Lead exposure and serum metabolite profiles in pregnant women in Mexico City

BACKGROUND

Lead (Pb) exposure is a global health hazard causing a wide range of adverse health outcomes. Yet, the mechanisms of Pb toxicology remain incompletely understood, especially during pregnancy. To uncover biological pathways impacted by Pb exposure, this study investigated serum metabolomic profiles during the third trimester of pregnancy that are associated with blood Pb and bone Pb.

METHODS

We used data and specimens from 99 women enrolled in the Programming Research in Obesity, Growth, Environment, and Social Stressors birth cohort in Mexico City. Maternal Pb exposure was measured in whole blood samples from the third trimester of pregnancy and in the tibia and patella bones at 1 month postpartum. Third-trimester serum samples underwent metabolomic analysis; metabolites were identified based on matching to an in-house analytical standard library. A metabolome-wide association study was performed using multiple linear regression models. Class- and pathway-based enrichment analyses were also conducted.

RESULTS

The median (interquartile range) blood Pb concentration was 2.9 (2.6) µg/dL. Median bone Pb, measured in the tibia and patella, were 2.5 (7.3) µg/g and 3.6 (9.5) µg/g, respectively. Of 215 total metabolites identified in serum, 31 were associated with blood Pb (p < 0.05). Class enrichment analysis identified significant overrepresentation of metabolites classified as fatty acids and conjugates, amino acids and peptides, and purines. Tibia and patella Pb were associated with 14 and 8 metabolites, respectively (p < 0.05). Comparing results from bone and blood Pb, glycochenodeoxycholic acid, glycocholic acid, and 1-arachidonoylglycerol were positively associated with blood Pb and tibia Pb, and 7-methylguanine was negatively associated with blood Pb and patella Pb. One metabolite, 5-aminopentanoic acid, was negatively associated with all three Pb measures.

CONCLUSIONS

This study identified serum metabolites in pregnant women associated with Pb measured in blood and bone. These findings provide insights on the metabolic profile around Pb exposure in pregnancy and information to guide mechanistic studies of toxicological effects for mothers and children.

Pervasive structural racism in environmental epidemiology

BACKGROUND

Epistemological biases in environmental epidemiology prevent the full understanding of how racism's societal impacts directly influence health outcomes. With the ability to focus on "place" and the totality of environmental exposures, environmental epidemiologists have an important opportunity to advance the field by proactively investigating the structural racist forces that drive disparities in health.

OBJECTIVE

This commentary illustrates how environmental epidemiology has ignored racism for too long. Some examples from environmental health and male infertility are used to illustrate how failing to address racism neglects the health of entire populations.

DISCUSSION

While research on environmental justice has attended to the structural sources of environmental racism, this work has not been fully integrated into the mainstream of environmental epidemiology. Epidemiology's dominant paradigm that reduces race to a mere data point avoids the social dimensions of health and thus fails to improve population health for all. Failing to include populations who are Black, Indigenous, and people of color (BIPOC) in health research means researchers actually know very little about the effect of environmental contaminants on a range of population health outcomes. This commentary offers different practical solutions, such as naming racism in research, including BIPOC in leadership positions, mandating requirements for discussing "race", conducting far more holistic analyses, increasing community participation in research, and improving racism training, to address the myriad of ways in which structural racism permeates environmental epidemiology questions, methods, results and impacts.

Gestational blood levels of toxic metal and essential element mixtures and associations with global DNA methylation in pregnant women and their infants

BACKGROUND

Pregnant women and their fetuses are exposed to multiple toxic metals that together with variations in essential element levels may alter epigenetic regulation, such as DNA methylation.

OBJECTIVES

The aim of the study was to investigate the associations between gestational levels of toxic metals and essential elements and mixtures thereof, with global DNA methylation levels in pregnant women and their newborn children.

METHODS

Using 631 mother-child pairs from a prospective birth cohort (The Norwegian Mother, Father and Child Cohort Study), we measured maternal blood concentration (gestation week ~18) of five toxic metals and seven essential elements. We investigated associations as individual exposures and two-way interactions, using elastic net regression, and total mixture, using quantile g-computation, with blood levels of 5-methylcytocine (5mC) and 5-hydroxymethylcytosine (5hmC) in mothers during pregnancy and their newborn children (cord blood). Multiple testing was adjusted for using the Benjamini and Hochberg false discovery rate (FDR) approach.

RESULTS

The most sensitive marker of DNA methylation appeared to be 5mC levels. In pregnant mothers, elastic net regression indicated associations between 5mC and selenium and lead (non-linear), while in newborns results indicated relationships between maternal selenium, cobalt (non-linear) and mercury and 5mC, as well as copper (non-linear) and 5hmC levels. Several possible two-way interactions were identified (e.g. arsenic and mercury, and selenium and maternal smoking in newborns). None of these findings met the FDR threshold for multiple testing. No net effect was observed in the joint (mixture) exposure-approach using quantile g-computation.

CONCLUSION

We identified few associations between gestational levels of several toxic metals and essential elements and global DNA methylation in pregnant mothers and their newborn children. As DNA methylation dysregulation might be a key mechanism in disease development and thus of high importance for public health, our results should be considered as important candidates to investigate in future studies.

A study on pyro-hydrometallurgical process for selective recovery of Pb, Sn and Sb from lead dross

This study is to propose a pyro-hydrometallurgical process for recovering Pb, Sn, and Sb from lead dross (LD), incorporating stages of roasting, leaching, and precipitation. The LD, containing 67.2% of Pb, 4.0% of Sn, and 1.4% of Sb, was first roasted at 750 °C for 2 h to oxidise the sulphide metals. Approximately 90% of Pb was oxidised from the first roasting. The LD was second roasted by mixing with 95% H₂SO₄ for sulphatising at 300 °C for 3 h to break the complex oxide structure of the oxyplumboromeite (Pb₂Sb₂O₇). After the two-step roasting process, over 99% of Pb was oxidised and Sb was separated. The calcine obtained was desulphurised by 2 M Na₂CO₃ solution for insoluble PbSO₄ to PbCO₃ for selective leaching. The residue was then leached in 2.5 M HNO₃ at 50 °C for 3 h and over 99% of Pb dissolved into the solution while Sn and Sb remained in the solid residue. The Pb containing solution was neutralised at pH 8 using 2 M Na₂CO₃ and over 99% Pb was precipitated as PbCO₃ and Pb hydroxides. A residue containing Sn and Sb was leached in 7 M NaOH at 95 for 1 h and over 99% Sn was leached selectively. Sn in the solution was precipitated at pH 7 using 2 M H₂SO₄ as SnO₂. Sb was recovered as Sb₂O₃ in solid reside from Sn leaching. The overall recovery rates of Pb, Sn, and Sb from the LD were 99.5%, 95.4%, and 86.3%, respectively. The proposed process is expected to contribute to recycling Pb and other metal values from LD by minimising hazardous waste emissions.

High Blood Lead Levels: An Increased Risk for Development of Brain Hyperintensities among Type 2 Diabetes Mellitus Patients

The current study was aimed to ascertain the effect of blood lead level on brain tissues in patients with type 2 diabetes. A total of 300 human participants ages 27 to 60 years with type 2 diabetes (n = 150) and healthy individuals (n = 150) were included in this study. The serum samples were used for measuring HbA1c and fasting blood glucose. Blood lead level was measured using flame atomic absorption spectrophotometer. Magnetic resonance imaging sub-analysis was used to assess the brain hyperintensities. Brain hyperintensities were found in 55% of patients with diabetes and 6% of non-diabetic control group subjects. The deep white matter hyperintensities were observed in 45% of diabetic patients, while the subcortical hyperintensities were noted in 10% of cases. Entorhinal cortex changes (31%) and hippocampus changes (42%) were noted in diabetic patients with brain hyperintensities. Diabetic patients with brain hyperintensities showed higher blood lead levels, HbA1c, and fasting blood sugar (p < 0.0001) as compared with healthy volunteers. A higher correlation (R² = 0.8922) was found between deep white matter hyperintensities' size and blood lead levels. In nutshell, persistence of high blood lead level in diabetic patients may progress to brain hyperintensities which may consequently lead to cognitive, behavioral changes and Alzheimer's disease.

Early occupational exposure to lead on neutrophil-to-lymphocyte ratio and genotoxicity

BACKGROUND

Lead (Pb) is known to induce detrimental health effects in exposed populations, including hematotoxicity and genotoxicity. Complete blood count (CBC) is a cost-effective and easy way to determine toxicity, and variations in proportion of different types of leukocytes: neutrophil-to-lymphocyte ratio (NLR) and lymphocyte-to-monocyte ratio (LMR) are further evidence of hematotoxicity. However, few studies have been conducted to systematically evaluate effects of occupational Pb exposure on NLR and LMR, and their associations with genotoxicity.

OBJECTIVES

Our study was aimed to systematically assess the effects of current occupational Pb exposure on NLR and LMR, and their associations with genotoxicity.

METHODS

Our investigation was performed on 1176 workers from a newly built battery factory in North China. The workers had just entered their current job position in recent years and most of them had no previous history of occupational exposure to Pb. Blood lead levels (BLLs) and leukocytes indices were detected for all participants. Cytokinesis-blocked micronucleus assay (MN; n = 675) and alkaline comet assay (% tail DNA; n = 869) were used to assess genotoxicity. Multivariate linear and Poisson regression analyses were conducted to examine associations between leukocytes indices, genotoxic biomarkers and BLLs with adjustment for covariates. Spearman correlation and mediation analyses were used to investigate relationships between NLR and genotoxicity.

RESULTS

Among all the exposed workers, NLR increased with increasing BLLs. However, WBC and LMR did not change significantly. Significant and dose-dependent increases in both MN frequencies and % tail DNA were observed among groups with different exposure doses. Compared with the normal NLR group (1.48 ≤ NLR < 4.58), the high NLR group (NLR ≥ 4.58) had higher % tail DNA. In addition, there was a significant and positive association between NLR and % tail DNA among all the workers, and % tail DNA mediated 15% of the effect of Pb on increasing NLR.

CONCLUSION

Our large-scale population study shows that Pb exposure increased NLR and induced genotoxicity. There was an association between elevated NLR and DNA damage. In addition, the mediation effect of % tail DNA on the relationship between BLLs and NLR provided mechanistic evidence that certain mechanisms, e.g. inflammation, may be involved in elevation of NLR from Pb exposure. Therefore, NLR may be a convenient and sensitive biomarker for indication of Pb toxicity. Further studies are needed to validate the proposed mechanism and NLR as a biomarker.

The Case For Cadmium and Lead Heavy Metal Screening

Exposure to cadmium and lead is widespread, and is related to environmental contamination, occupational sources, food, tobacco and other consumer products. Lower socioeconomic status increases the risk of heavy metal exposure and the diseases associated with cadmium and lead toxicity. Concurrent toxicity with both cadmium and lead is likely but has not often been assessed. There is now substantial evidence linking cadmium and lead to many diseases including hypertension, diabetes mellitus, obesity, cancer, coronary artery disease, chronic kidney disease (CKD) and lung disease. Both chronic renal failure and ischemic heart disease patients have been treated separately in recent studies with calcium disodium ethylenediaminetetraacetic acid (Ca EDTA) chelation therapy. In patients with CKD, serum creatinine 1.5-4.0 mg/dL, and increased body lead burden, weekly low dose chelation with Ca EDTA slowed the rate of decline in renal function in diabetics and non-diabetics. In patients with a history of myocardial infarction, the Trial to Assess Chelation Therapy (TACT) study showed that Ca EDTA chelation decreased the likelihood of cardiovascular events, particularly in diabetics. Ca EDTA chelation administered carefully at lower dosage (<50 mg/kg per week) is generally safe. In the past, acute renal failure associated with much higher dosage was reported. We suggest that the preponderance of the evidence favors a more activist approach towards diagnosis and possible intervention in heavy metal toxicity.

Worker health in formal electronic waste recycling plants

Purpose

This article explores the protective measures and the occupational health and safety (OHS) prevention strategies in place in the formal electronic equipment recycling (e-recycling) industry, more specifically in the Greater Montreal area (Quebec, Canada) and their consequences: health inequalities and level of compliance with environmental standards.

Design/methodology/approach

Semi-structured interviews were conducted using two respondent-specific questionnaires, one for workers and one for supervisors. Data collection and analytic procedures drew from qualitative content analysis. It was tempted to identify differences in OHS practices in relation to the workers' employment status and to link the companies' OHS concerns to their level of compliance with environmental standards.

Findings

The article highlights specific OHS issues in the formal e-recycling industry. Enforcing compliance with environmental standards as a lever for promoting OHS appears to be a promising strategy. Another main finding was the workforce diversity and related OHS vulnerabilities in this industry and the challenges they pose to employers' ability to adequately and equally reach and protect all workers involved.

Originality/value

To date, too little attention appears to have been paid to working conditions and worker protection in this rapidly growing sector. Specific prevention programmes could be implemented and adapted to the industry's diverse workforce and its multiple OHS vulnerabilities. This issue calls for the international community to take responsibility, as many electronic waste (e-waste) generated worldwide is shipped to developing countries, where lack of regulation and control is much more striking in a sector that remains very largely informal.

Symptomatic Lead Toxicity and Joint Pain Because of Migration of Shotgun Pellets into the Hip 12 Years After Injury: A Case Report

CASE

We describe a case of mild lead poisoning in a 25-year-old woman because of intra-articular migration of lead shot 12 years after gunshot injury to the left hip, ameliorated by arthroscopic foreign body removal. Retained lead can cause systemic symptoms of lead toxicity, supranormal blood lead concentration, and increasingly painful and destructive local arthritis even years after gunshot injury.

CONCLUSION

This report shows that lead fragments should be monitored closely if located near joint spaces. We demonstrate curative therapy for lead poisoning through the use of minimally invasive arthroscopic techniques for removal of retained intra-articular lead missiles.

Unified Probability Distribution and Dynamics of Lead Contents in Human Erythrocytes Revealed by Single-Cell Analysis

Understanding the presence and dynamics of chemical pollutants in individual cells is fundamentally important for their trafficking, fate, and toxicity in humans. The presence of molecular components (i.e., proteins and mRNA) in individual cells of higher organisms is considered a stochastic event. The characteristics of chemical pollutants, as extrinsic compounds, in subpopulation of human cells on single-cell basis have not been explored yet. Here, we demonstrated the lead (Pb) content in individual mature erythrocytes (m-erythrocytes) of Pb-intoxicated patients, and healthy subjects exhibited a unified pattern in probability distribution (gamma distribution) and dynamics, despite being highly heterogeneous. The Pb content in individual m-erythrocytes decreased with the lifetime of m-erythrocytes. Meanwhile, the distribution and dynamics were found to be highly related to the Pb content in m-erythrocytes and was independent of patients and their status. This is the first study to analyze the distribution pattern of chemical pollutants at a single-cell level in higher organisms. This study sheds light on the molecular mechanism of Pb trafficking and fate in humans and the search for an efficient strategy to improve Pb excretion during Pb treatment.

Probabilistic pharmacokinetic modeling of airborne lead corresponding to toxicologically relevant blood lead levels in workers

The Department of Defense (DOD) commissioned the National Research Council (NRC) to assess the potential health effects associated with exposure of DOD personnel to lead (Pb) at firing ranges. In that report, NRC concluded that the current Occupational Safety and Health Administration permissible exposure limit and the blood lead levels (BLLs) on which it was based were not sufficiently protective of worker populations covered under the general industry standard. In support of future selection of an occupational exposure limit, the relationship of airborne Pb levels to BLLs is of interest to the DOD. A subset of the BLLs identified as relevant to the management of health risks of exposed workers was selected as targets for extrapolation to equivalent airborne Pb values. The existing O'Flaherty physiologically based pharmacokinetic model for Pb in humans was modified to facilitate probabilistic predictions of DOD worker population BLLs, including 95th percentile values, based on current worker characteristics. Workplace airborne Pb 8-h time-weighted average concentrations of 1.1, 4.0, 6.8, or 9.8 μg/m³ are anticipated to maintain BLLs below 5, 10, 15, or 20 μg/dl, respectively, in the vast majority of DOD workers exposed to Pb under full-time working lifetime occupational exposure.

Chronic Low-Level Lead Exposure Increases Mesenteric Vascular Reactivity: Role of Cyclooxygenase-2-Derived Prostanoids

Lead (Pb) exposure causes hazardous effects as hypertension and other cardiovascular diseases. We evaluated whether chronic Pb exposure alters the peripheral vascular resistance measuring the vascular reactivity of mesenteric resistance arteries in rats to identify the underlying mechanisms that are associated to the development of Pb-induced hypertension. Mesenteric resistance arteries from lead-treated and untreated Wistar rats (1st dose: 10 μg/100 g; subsequent doses: 0.125 μg/100 g, intramuscular, 30 days) were used. Contractile responses to phenylephrine increased, while acetylcholine and sodium nitroprusside-induced relaxation was not affected by lead treatment. Endothelium removal and inhibition of NO synthase by L-NAME similarly enhanced the response to phenylephrine in untreated and lead-treated rats. The antioxidants apocynin and superoxide dismutase (SOD) did not affect vasoconstriction in either group. The vascular expression of cyclooxygenase-2 (COX-2) protein increased after lead exposure. The respective non-specific or specific COX-2 inhibitors indomethacin and NS398 reduced more strongly the response to phenylephrine in treated rats. Antagonists of EP1 (SC19220), TP (SQ29548), IP (CAY10441) and angiotensin II type 1 (losartan) receptors reduced vasoconstriction only in treated rats. These conclusions present further evidence that lead, even in small concentration, produces cardiovascular hazards being an environmental contaminant that account for lead-induced hypertension.

Significant association between blood lead (Pb) level and haemoglobin A1c in non-diabetic population

Although many heavy metals are necessary for normal biological function, a subset of heavy metals have no role in human physiology, such as lead (Pb) and arsenic (As). Such elements have deleterious effects on physiology and be associated with the incidence of diabetes and related metabolic syndromes. Haemoglobin A1c (HbA1c) is not only a useful diagnostic and prognostic parameter in patients with diabetes, but it is also helpful in prediction of future diabetic risk in non-diabetic patients. However, no studies have evaluated the relationship between heavy metal concentration and HbA1c in non-diabetic patients. Therefore, the present study was designed to address this issue. We performed surveys for general populations living in southern Taiwan from June 2016 to September 2018. All participants received face-to-face interviews, laboratory tests, and measurements of weight and height, waist circumference, heart rate, and systolic and diastolic blood pressures. HbA1c was positively associated with Log blood Pb, after adjustments for age, body mass index, fasting blood glucose, total cholesterol, and triglyceride. Additionally, a Log 1 μg/dL increase in Pb was associated with a small (0.819 mmol/mol, 95% confidence interval = 0.072-1.566) increase in HbA1c (P =  0.032). No association with HbA1c was observed for urine nickel, chromium, manganese, As, copper, and cadmium in the multivariable analysis. In conclusion, after adjusting for important clinical parameters, Log blood Pb was positively associated with HbA1c in our non-diabetic population. This finding implies that high blood Pb might have the potential to predict future diabetic risk in non-diabetic populations. Further prospective studies are necessary to validate this issue.

Acute lead poisoning: a diagnostic challenge in the emergency department

Acute abdominal pain is a common presentation to the emergency department (ED). Ruling out life-threatening causes and giving pain relief are the most important tasks in ED. We describe a 32-year-old man who presented to ED with abdominal pain and vomiting which was unrelieved by usual doses of analgesic. Extensive investigations revealed no significant abnormalities. On further probing, he admitted taking traditional medications for infertility. The toxicological panel revealed a high blood lead level, leading to a diagnosis of acute lead toxicity. Chelation therapy with D-penicillamine was initiated and the patient's abdominal pain resolved within 4 days.

Development of a benchmark dose for lead-exposure based on its induction of micronuclei, telomere length changes and hematological toxicity

BACKGROUND

Excessive lead exposure is associated with adverse health effects. However, there is a lack of systematic investigation using large populations to ascertain acceptable exposure limits.

OBJECTIVES

Our study was aimed to identify human exposure-response relationships between lead exposure and health-related outcomes, and to determine a benchmark dose (BMD).

METHODS

A total of 1896 participants from a lead-acid battery plant were recruited. Blood lead levels (BLLs) were detected for all participants. Hematological parameters (n = 1896), micronuclei (MN) frequencies (n = 934), and relative telomere length (rTL) (n = 757) were also determined. Multivariate linear/Poisson regression analyses were performed to examine associations between BLLs and these health outcomes. Restricted cubic splines were used to identify dose-response relationships. Three BMD approaches were used to calculate BMD and its 95% lower confidence limit (BMDL).

RESULTS

Among all participants, BLLs show a right-skewed distribution (median, 185.40 μg/L; 25th - 75th percentile, 104.63-271.70 μg/L). There existed significant differences for red blood cell (RBC), hemoglobin (Hb), MN and rTL among different BLL dose groups. After adjusting for possible confounders, all indicators were significantly associated with BLLs. Restricted cubic splines show that there were linear dose-response relationships for RBC and Hb with BLLs, while non-linear for MN and rTL. Results from the three BMD approaches indicate that the dichotomous models were better than continuous models to calculate BMD and BMDL of BLLs. The conservative BMDL obtained from RBC data was 135 for total, 104 for male and 175 μg/L for female. The corresponding BMDL obtained from Hb data was 105 for total, 116 for male and 70 μg/L for female. As for MN data, the BMDL estimate was 66 for total, 69 for male and 64 μg/L for female. Finally, the BMDL from rTL data was 35 for total, 32 for male and 43 μg/L for female.

CONCLUSIONS

Our data show significant dose-response relationships between lead exposure and expressions of hematological toxicity and genotoxicity. The new BMDLs of 135 and 105 μg/L based on RBC and Hb, and even more strict level of 66 and 35 μg/L based on MN and rTL are lower than current exposure limits in China. Therefore, the four values can be considered as novel exposure limits. In addition, sex effect should be taken into account when setting occupational health standard. Considering that different biomarkers have different sensitivities, better understanding their relationships will certainly improve the current emphasis on precision health risk assessment.

Associations of blood lead levels with multiple genotoxic biomarkers among workers in China: A population-based study

Carcinogenic effects from low doses of lead (Pb) exposure to populations have been suspected but not concluded. Therefore, a large-scale cross-sectional study was conducted by us to investigate genotoxic effects from Pb exposure during 2016-2018 in North China. Blood lead levels (BLLs) and cumulative blood lead levels (CBLLs) were measured. Multiple relevant biomarkers were used to assess genotoxicity of Pb: mitochondrial DNA copy number (mtDNAcn, n = 871), Comet Tail Intensity (n = 872), γ-H2AX (n = 345), relative telomere length (rTL, n = 757), micronuclei (MN, n = 934) and phosphatidylinositol glycan class A mutation (PIG-A, n = 362). The BLL data show right-skewed distribution, with increase of the median (P25, P75) from 17.4 (8.9, 26.4) μg/dl in 2016 to 18.5 (10.5, 27.2) μg/dl in 2017, and to 20.8 (11.3, 31.0) μg/dl in 2018. Multivariate regression analyses show that mtDNAcn was non-linearly associated with BLLs or CBLLs, i.e. decreased at low levels but increased at the higher levels. Comet and Micronuclei data show positive dose-response relationships with BLLs as well as CBLLs. γ-H2AX data show an overall increased trend with BLLs while rTL data show a shortening trend. No associations were found for PIG-A mutation with Pb exposure. Our findings indicate that current low dose exposure to Pb can still cause health hazards to occupational populations, and the mechanism may be via the induction of DNA & chromosome damage rather than via the mutagenesis pathway.

Broadening the List of Differential Diagnosis for Acute Abdomen - a Case Report from Nepal

When a patient has an acute abdominal pain, it is important to identify if the underlying cause is life threatening. To that end, a thorough medical history and relevant investigation will be pivotal. Here we report a case of lead toxicity where the patient presented with an acute abdomen following intake of Ayurvedic medicines. The baseline blood lead level was 82.3 μg/dl. The Ayurvedic medicines when analyzed for its lead content, revealed high lead concentration. We observed that the cessation of Ayurvedic medication along with D-penicillamine therapy was beneficial in reducing the blood lead level and in alleviating abdominal pain. Our findings implicate the need of awareness program regarding the potential health hazards associated with the use Ayurvedic medicines.

Reduction in lead exposures with lead-free ammunition in an advanced urban assault course

The training of soldiers for urban conflict involves marksmanship instruction on outdoor flat ranges and the teaching of close-quarter battle techniques in indoor facilities, referred to as shoot houses, where intense firing exercises can generate high air lead levels from small arms ammunition, flash bang grenades, and explosive devices. Levels of lead and copper in air were evaluated during five training activities of a 45-day training course using both stationary general area and breathing zone sampling over a 2-year period. Individual blood lead values were determined prior to and at course completion. Mean breathing zone lead concentrations for the five training activities ranged from 0.014 on the outdoor flat range to 0.064 mg/m³ inside shoot houses; with a change to lead-free ammunition the values were reduced to a range of 0.006-0.022 mg/m³. Isolated flash bang grenades generated very high general area lead concentrations (2.0 mg/m³), which in training were associated with the highest measured breathing zone concentration (0.16 mg/m³). For copper, mean breathing zone concentrations increased from 0.010 to 0.037 mg/m³ with the change to lead-free frangible ammunition on the outdoor range, but remained below the permissible exposure limit for copper fume. Inside shoot houses, mean breathing zone copper concentrations exceeded the permissible exposure limit with ball and lead-free frangible ammunition, ranging from 0.077-0.13 mg/m³. With the introduction of lead-free ammunition, when comparing the blood lead differences between start and finish of the course, there was a significant reduction in the mean blood lead difference from 13.3 µg/dL to 5.4 µg/dL. Options for mitigation of potentially high exposure areas using improved ventilation designs are discussed. These results advocate for improved designs for shoot house training facilities, stress the importance of removing lead from ammunition and explosive devices for training, and promote the continued need for implementation of controls to mitigate and manage metal exposures during training.