Effects of occupational lead exposure on renal and nervous system of workers of traditional tile factories in Mashhad (northeast of Iran)

Analysis of blood lead level and its clinical significance among occupational exposed painters in chennai based population: A cross sectional study

INTRODUCTION AND AIM

Lead is a ubiquitous element found in the earth crust. There is no known physiologic role of lead in human body and hence any amount of lead present in human tissue considered as a contamination. Several studies on lead toxicity show that, occupational exposure remains the main source for lead toxicity and is emerging as important public health problem. Burden and severity of occupational exposure of lead and its clinical significance are gaining more interest in the field of toxicology. Only limited studies are available and there is scarcity of epidemiology data to assess the blood lead levels of workers and the contribution of common workplace practices to lead exposure in India especially from our region. So, the current study is designed to assess the blood lead levels (BLL) and its clinical significance among high risk workers especially painters working in the construction and public private sector in Chennai based population.

MATERIALS AND METHODS

This cross-sectional case control study included 122 painters and 122 healthy individuals. A detailed questionnaire about demographic details, personal habits, work related safety precautions, presenting symptoms of lead toxicity were given to painter followed by detailed medical examination and blood investigations including blood lead levels were collected and statistically analyzed. The t-test were used to compare mean blood lead levels and to investigate the associations between specific job type, use of self-protection device,sex, service years and occurrence of non-specific symptoms with BLLs.

RESULTS

The mean BLL of the painters were less than the recommended threshold level. Among painters 13.1% were categorized under BLL > 10 μg/dL. The higher BLL among the painters were directly proportional to year of experience and poor usage of personal protective materials. The levels of Hb, HCT and eosinophil were much correlated with lead toxicity. A marginal significance were observed in some parameters especially urea and creatinine when compared with control. The Cognitive dysfunction, hypertension and renal dysfunction were also observed among the painters.

CONCLUSION

The BLL in painters among our group were minimal compared to biological reference value. Duration of exposure and association of patient's clinical features like cognitive dysfunction, hypertension and renal dysfunction conditions were observed and this should be carefully monitored and study on huge population of painters with longitudinal aspect is recommended to rule out the clinical correlation of lead toxicity.

Biochemical and hematological effects of lead exposure in Iranian battery workers

OBJECTIVE

The purpose of our study was to evaluate the hematotoxic, hepatotoxic, and nephrotoxic responses following lead exposure among battery workers.

MATERIAL AND METHODS

Seventy-eight battery workers exposed to lead, and 78 non-exposed subjects were studied. Fasting blood samples were collected to assess kidney and liver function and hematological parameters. To determine the breathing zone and blood lead levels (BLLs), the samples were analyzed in accordance with the 7082 and 8003 NIOSH methods, respectively.

RESULTS

The battery workers had significantly higher breathing zone lead and BLLs than the non-exposed group. In battery workers, the most hematological parameters, including red blood cell, hemoglobin, mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration, have significantly decreased. In contrast, white blood cell count has shown a significant increase as compared to the controls. The mean levels of alanine aminotransferase, aspartate aminotransferase as biomarker liver damage, and the serum levels of creatinine as a result of renal failure were significantly higher in the exposed group than in the non-exposed group.

CONCLUSIONS

These observations indicate that occupational exposure to lead exceeding its current threshold limit value (TLV) and biological exposure index (BEI) is associated with hematological symptoms and liver and kidney dysfunction.

Low-level Eexposure to lead dust in unusual work schedules and hematologic, renal, and hepatic parameters

BACKGROUND

Many workers are exposed to lead dust in lead-‑zinc mines. Exposure to this heavy toxic metal and its compounds can cause irreversible adverse health effects.

OBJECTIVE

To assess possible hematotoxic, nephrotoxic, and hepatotoxic potentials of low levels of lead in a group of mine workers exposed to this heavy metal in an unusual work schedule.

METHODS

A total of 73 exposed and 70 non-exposed employees were interviewed. Demographic data, and occupational and medical history of the employees were obtained by questionnaires. Air monitoring was performed to determine the workers' time-weighted average (TWA) exposure to lead dust. The threshold limit value (TLV) for lead was adjusted for unusual work schedules according to the model developed by the University of Montreal and the Institute de Recherche en Sante et en Securite du Travail (IRSST). Blood samples were collected for complete blood count, liver and kidney function tests. Data were analyzed using version 21.0 of the SPSS software.

RESULTS

The TWA exposure of workers was 24 μg/m³. On average, the worker's exposure to lead dust did not exceed the 8-h OSHA and ACGIH TLV-TWA of 50 μg/m³. Significant associations were found only between exposure to lead and platelet count, red cell distribution width, total protein, and albumin.

CONCLUSIONS

Exposure to low levels of lead dust in unusual work schedules was not associated with overt hematotoxicity, hepatotoxicity or nephrotoxicity. However, mild, sub-clinical, pre-pathologic significant changes were noted in some blood parameters of the exposed employees as compared with their referent counterparts.

Long-Term Exposure to Low-Dose Lead Induced Deterioration in Bone Microstructure of Male Mice

The aim of this study was to investigate the long-term effects of low-dose lead exposure on bone microstructure in mice. Ten SPF 12-week-old male C57BL/6J mice were randomly divided into two groups: control (deionized water) and lead exposure (150 ppm of lead acetate in drinking water). After 24 weeks treatment, mice were weighed and the left femurs were collected and stored at - 80 °C. The right femurs of the mice were scanned by Micro-CT for three-dimensional reconstruction, and bone mineral density, bone volume fraction, trabeculae thickness, trabeculae number, and trabeculae separation were measured. The right tibia was collected to investigate histopathological changes in H&E-stained sections. The gene expression of osteoprotegerin (OPG), RANKL, and runt-related transcription factor 2 (Runx2) was determined using real-time PCR. The bone density of femoral cancellous bone and the number of cancellous bone trabeculae in the lead exposure group were both significantly decreased compared with the control group. Bone marrow stromal cell numbers were decreased following lead administration, and lipid droplet vacuoles were observed in the lead group. Levels of OPG were significantly decreased in the lead group, and lead also inhibited the expression of Runx2 compared with the control group. Long-term exposure to low doses of lead can cause bone damage without inducing other obvious symptoms through decreasing bone density and the number of cancellous bone trabeculae, further suppressing bone formation. It suggests that lead may exacerbate bone loss and osteoporosis, especially in the elderly.

Lead poisoning; a neglected potential diagnosis in abdominal pain

Background

Abdominal pain may be a presenting symptom of lead poisoning and is often difficult to diagnose. This study aimed to determine the prevalence of abdominal pain in patients seen in the Laghman Hakim Hospital ED and GI clinic who were lead-intoxicated, with or without opiate use disorder.

Methods

Between July 2017 and January 2018, patients seen in the ED and GI clinic of Loghman Hakim Hospital with unexplained abdominal pain or abdominal pain resistant to treatment were enrolled. Informed consent was obtained from potential enrollees. For standardization, a pre-designed data collection tool was developed for uniform data acquisition. Opiate use was determined historically. For this study, lead poisoning was defined as a blood lead level (BLL) greater than or equal to 30 μg/dL (1.45 μmol/L) with concomitant GI symptoms.

Results

Of 125 patients admitted, 28 (22.4%) had BLLs higher than 30 μg/dL. None of the patients had signs and symptoms of opioid withdrawal syndrome during evaluation. Elevated BLLs were significantly correlated with oral opium use/abuse, history of addiction for over the preceding 12 years. The daily opium use was more than 2.75 g. There was a statistical correlation between lead toxicity and abdominal pain consistency and intensity, constipation, and paresthesias. Anemia, leukocytosis, and abnormal liver enzyme tests were laboratory findings associated with lead toxicity. Four patients died, one of whom was diagnosed with lead toxicity.

Conclusion

Lead toxicity should be considered in the potential differential diagnosis of severe and resistant abdominal pain in patients referring to general EDs or GI clinics if a positive history of opium abuse exists.

A systematic review on status of lead pollution and toxicity in Iran; Guidance for preventive measures

Lead is an old environmental metal which is presented everywhere and lead poisoning is an important health issue in many countries in the world including Iran. It is known as a silent environmental disease which can have life-long adverse health effects. In children, the most vulnerable population, mental development of children health effects is of the greatest influence. Low level lead exposure can significantly induce motor dysfunctions and cognitive impairment in children. The sources of lead exposure vary among countries. Occupational lead exposure is an important health issue in Iran and mine workers, employees of paint factories, workers of copying centers, drivers, and tile making factories are in higher risk of lead toxicity. Moreover lead processing industry has always been a major of concern which affects surface water, drinking waters, and ground waters, even water of Caspian Sea, Persian Gulf and rivers due to increasing the number of industries in vicinity of rivers that release their waste discharges into river or sea. In addition, lead contamination of soil and air especially in vicinity of polluted and industrialized cities is another health problem in Iran. Even foods such as rice and fishes, raw milk, and vegetables which are the most common food of Iranian population are polluted to lead in some area of Iran. Adding lead to the opium is a recently health hazard in Iran that has been observed among opium addicts. There are few studies evaluated current status of lead exposure and toxicity in the Iranian children and pregnant women which should be taken into account of authorities. We recommend to identify sources, eliminate or control sources, and monitor environmental exposures and hazards to prevent lead poisoning.

Comparison of therapeutic effects of garlic and d-Penicillamine in patients with chronic occupational lead poisoning

Previous studies on animals have revealed that garlic (Allium sativum) is effective in reducing blood and tissue lead concentrations. The aim of this study was to investigate therapeutic effects of garlic and compare it with d-penicillamine in patients with chronic lead poisoning. After coordination and obtaining informed consent, clinical examinations and blood lead concentration (BLC) of 117 workers at a car battery industry were investigated. BLC was determined by heated graphite atomization technique of an atomic absorption spectrometer. The workers were randomly assigned into two groups of garlic (1200 μg allicin, three times daily) and d-penicillamine (250 mg, three times daily) and treated for 4 weeks. BLC was determined again 10days post-treatment. Clinical signs and symptoms of lead poisoning were also investigated and compared with the initial findings. Clinical improvement was significant in a number of clinical manifestations including irritability (p = 0.031), headache (p = 0.028), decreased deep tendon reflex (p=0.019) and mean systolic blood pressure (0.021) after treatment with garlic, but not d-penicillamine. BLCs were reduced significantly (p=0.002 and p=0.025) from 426.32±185.128 to 347.34±121.056 μg/L and from 417.47±192.54 to 315.76±140.00μg/L in the garlic and d-penicillamine groups, respectively, with no significant difference (p=0.892) between the two groups. The frequency of side effects was significantly (p=0.023) higher in d-penicillamine than in the garlic group. Thus, garlic seems safer clinically and as effective as d-penicillamine. Therefore, garlic can be recommended for the treatment of mild-to-moderate lead poisoning.