The effect of low-level blood lead on hematologic parameters in children

Association between blood lead levels and parathyroid hormone among United States adolescents aged 12-19: a cross-sectional study

Aims

Studies on the association between serum lead levels and parathyroid function in adolescents are lacking. Therefore, in this study, we elucidated the possible association between blood lead levels (BLLs) and the parathyroid hormone (PTH) in adolescents aged 12-19 years in the United States.

Methods

In this study, information from the database of the National Health and Nutrition Examination Survey was utilized. The study included 3919 participants from survey cycles between 2003-2004 and 2005-2006. Multivariable linear regression analysis was performed to determine the correlation between BLLs and PTH. Furthermore, smooth curve fitting was utilized to analyze the dose-response relationship between BLLs and PTH.

Results

Multivariable linear regression analysis revealed that every 1 μg/dL increase in BLLs was associated with 0.67 pg/mL increase in PTH (β = 0.67, 95% CI: 0.16-1.18, p < 0.01). However, sex-stratified subgroup analysis revealed that this positive association was only observed in males (β = 1.16, 95% CI: 0.50-1.83 p < 0.01). Smooth curve fitting revealed a positive correlation between BLLs and PTH.

Conclusions

In adolescents in the United States, BLLs are positively correlated with PTH, particularly in males.

Lung Toxicity and Molecular Mechanisms of Lead-Based Perovskite Nanoparticles in the Respiratory System

Lead-based perovskite nanoparticles (Pb-PNPs) have found extensive applications across diverse fields. However, because of poor stability and relatively strong water solubility, the potential toxicity of Pb-PNPs released into the environment during their manufacture, usage, and disposal has attracted significant attention. Inhalation is a primary route through which human exposure to Pb-PNPs occurs. Herein, the toxic effects and underlying molecular mechanisms of Pb-PNPs in the respiratory system are investigated. The in vitro cytotoxicity of CsPbBr3 nanoparticles in BEAS-2B cells is studied using multiple bioassays and electron microscopy. CsPbBr3 nanoparticles of different concentrations induce excessive oxidative stress and cell apoptosis. Furthermore, CsPbBr3 nanoparticles specifically recruit the TGF-β1, which subsequently induces epithelial-mesenchymal transition. In addition, the biodistribution and lung toxicity of representative CsPbBr3 nanoparticles in ICR mice are investigated following intranasal administration. These findings indicate that CsPbBr3 nanoparticles significantly induce pulmonary inflammation and epithelial-mesenchymal transition and can even lead to pulmonary fibrosis in mouse models. Above findings expose the adverse effects and molecular mechanisms of Pb-PNPs in the lung, which broadens the safety data of Pb-PNPs.

Effects of Sub-chronic Lead Exposure on Essential Element Levels in Mice

Lead (Pb), a corrosion-resistant heavy non-ferrous metal, is one of the most common environmental neurotoxic metals. The effects of Pb on other essential metal elements are contradictory. Therefore, this in vivo study addressed the effects of sub-chronic Pb exposure on the distribution of other divalent metals, exploring the relationships between Pb levels in blood, teeth, bones, hair, and brain tissues. Thirty-two healthy male C57BL/6 mice received intragastric administration (i.g.) with 0, 12.5, 25, and 50 mg/kg Pb acetate, once a day for 8 weeks. Levels of Pb and other metal elements [including iron(Fe), zinc (Zn), magnesium (Mg), copper (Cu), and calcium(Ca)] in the whole blood, teeth, the right thighbone, hair, and brain tissues (including cortex, hippocampus, striatum, and hypothalamus) were detected with inductively coupled plasma-mass spectrometry (ICP-MS). Pb levels in all detected organs were increased after Pb-exposed for 8 weeks. The results of relationship analysis between Pb levels in the tissues and lifetime cumulative Pb exposure (LCPE) showed that Pb levels in the blood, bone, and hair could indirectly reflect the Pb accumulation in the murine brain. These measures might serve as valuable biomarkers for chronic Pb exposure reflective of the accumulation of Pb in the central nervous system (CNS). Sub-chronic Pb exposure for 8 weeks altered Ca, Cu, Fe, and Zn levels, but no effects were noted on Mg levels in any of the analyzed tissues. Pb decreased Ca in teeth, Cu in thighbone and teeth, Zn in whole blood and hair, and Fe in hair. In contrast, Pb increased Ca levels in corpus striatum and hypothalamus, Cu levels in striatum, Zn levels in teeth, and Fe levels in hippocampus, thighbone, and teeth. The Pb-induced changes in metal ratios in various tissues may serve as valuable biomarkers for chronic Pb exposure as they are closely related to the accumulations of Pb in the murine CNS. The results suggest that altered distribution of several essential metal elements may be involved in Pb-induced neurotoxicity. Additional studies should address the interaction between Pb and essential metal elements in the CNS and other organs.

Kindergarten indoor dust metal(loid) exposure associates with elevated risk of anemia in children

Exposure to metals and metalloids in indoor dust is associated with adverse health effects in young children, but there is limited evidence for an association with anemia, which is at high risk in children. The aim of this study was to investigate the association between exposure to multiple metal(loid)s in indoor dust in kindergartens and the risk of anemia in children. In 2021, 2165 children from 25 kindergartens in eastern China were included in the study and had their hemoglobin (Hb) measured. Indoor dust samples were collected from the children's kindergartens, and the concentrations of 11 metals and metalloids in the samples were measured using inductively coupled plasma mass spectrometry (ICP-MS). The daily exposure dose (DED) of dust was used to assess the risk of metal(loid) exposure in the children. The results showed that of the 2165 children with available data, 351 (16.2 %) met the WHO definition of anemia. In multiple linear regression and logistic regression analyses, we found that for each quartile of DED increase in Cd inhalation, child Hb levels decreased by 2.703 g/L (95 % CI: -4.055, -1.351), and the risk of anemia increased 1.602-fold (95 % CI: 1.087, 2.360). Mn ingestion was associated with increased odds of anemia [odds ratio (OR) = 1.760 (95 % CI: 1.217, 2.544)]. Interaction analysis indicated that metal(loid)s exposure effects were modified by child sex, age, and body mass index (BMI). Cluster analysis found that children at high risk of metal(loid) exposure in the school environment tended to have lower Hb levels and higher prevalence of anemia compared with those at low risk, although this was not statistically significant. These findings suggest that child school exposure to metal(loid)s in indoor dust is associated with an increased risk of developing anemia in children, modified by child sex, age, and BMI.

Role of environmental lead in the occurrence of anemia in Indian children: a systematic review and meta-analysis

Exposure to lead among children, as well as adults, is a major global health issue. With diverse routes of exposure (e.g., food, air, and water) either environmentally or occupationally, lead among children can cause mild, moderate, to severe health complications in the later stages of life. The average blood lead level reported by CDC in 2021 is 3.5 µg/dL, and the level of blood lead toxicity is ≥ 10 μg/dL. In this study, we planned to systematically analyze the association between blood lead levels (BLLs) (≥ 10 μg/dL and < 10 μg/dL) and the risk of anemia (hemoglobin level < 11 g/dL) among Indian children aged between ≥ 1 and ≤ 18 years. An online literature search of 5 databases, PubMed, Ovid, EMBASE, Web of Science, and Google Scholar was accomplished with a search updated until 8^th March 2021. Study designs included cohort, cross-sectional, and case-control studies that have evaluated the association of lead toxicity or exposure with anemia (Hb < 11 g/dL) reported in urban and/or rural Indian children. Meta-analysis was performed among a total of 864 children from 4 cross-sectional studies. The association between lead toxicity (BLLs ≥ 10 μg/dL) and the risk of being anemic was not statistically significant (RR = 1.15 (95% CI: 0.86-1.55, I² = 77%). The risks of bias in all included studies were low according to the Newcastle Ottawa Scale. Increased blood lead levels did not appear to be the major contributor to anemia in Indian Children. We need to focus primarily on improving the nutritional quality, fortified food supplements, and a balanced diet for children to reduce the anemia burden in India. Lead toxicity should be sought as an etiological factor only in areas of high environmental risk factors which were leaded paints, leaded batteries, a house near major road/traffic areas, and pesticide exposure.

Gender Difference in the Associations among Heavy Metals with Red Blood Cell Hemogram

This study aimed to investigate gender differences in the association between heavy metals and hemograms including hemoglobin (Hgb), mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC). A health survey of 2447 participants was conducted in southern Taiwan between June 2016 and September 2018. Seven heavy metals were measured: blood lead (Pb), urine nickel (Ni), urine chromium (Cr), urine manganese, urine arsenic (As), urine copper and urine cadmium (Cd). The results show that in females, Pb and Ni were significantly negatively associated with Hgb. In addition, As and Cd were significantly positively, and Pb and Ni were significantly negatively, associated with MCV, in males and females, respectively. The interactions between gender and Ni and gender and Cd in MCV were statistically significant. Further, Pb, in males, and Pb, Ni and Cr, in females, were significantly negatively associated with MCHC. In conclusion, in females, associations of red blood cell (RBC) hemograms with heavy metals such as Pb and Ni were found. In males, heavy metals such as Pb, As and Cd were found to associate with RBC hemograms. Further research is warranted to discuss the mechanism behind these associations.

An integrated assessment of lead exposure in children: Correlation with biochemical and haematological indices

BACKGROUND

Lead (Pb) is a worldwide concern due to its persistent property in the environment. However, due to diminutive evidence and elusiveness, the impact of lead exposure on the biochemical and haematological parameter in school-age children is not well established.

AIM

This study primarily aimed to investigate blood lead (BL) in children and its association with haematological and biochemical parameter.

METHODS

A total of 43 children (4-12 years) were recruited in each control and study group. Furthermore, the study group were subdivided into two groups (group A (<10 μg/dl) and group B (>10 μg/dl)). BL level, haematological parameter including haemoglobin, packed cell volume, red blood cells, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, total leukocytes count, neutrophils, lymphocytes, monocytes, mean corpuscular volume, red cell distribution width, eosinophil's, platelets in the whole blood and biochemical parameter such as liver function test (total bilirubin, alkaline phosphatase, serum glutamic-oxaloacetic transaminase, serum glutamic-pyruvic transaminase, total protein, albumin) and kidney function test (sodium, potassium, blood urea nitrogen, creatinine) in serum were measured using anodic stripping voltammeter (ASV), Cell-Dyn Ruby Haematology analyser, Beckman coulter Unicel Dxc 800 Synchron Clinical analyser respectively.

RESULTS

The arithmetical mean of BL level was 19.93 ± 9.22 μg/dl (median: 17.5 μg/dl; range 9.1-37.4 μg/dl). Only 21 % children had BL levels <10 μg/dl and there were 79 % children with BL levels >10 μg/dl. Blood mean corpuscular haemoglobin concentration, Neutrophils, Monocytes were significantly higher between the control and study group. Additionally, haemoglobin, packed cell volume, red blood cells, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, Lymphocytes and mean corpuscular volume intensities were significantly lower in >10 μg/dl group whereas total leukocytes count, neutrophils, monocytes, red cell distribution width, eosinophil's, platelets levels were statistically higher (p < 0.001). Serum alkaline phosphatase, serum glutamic-oxaloacetic transaminase, total protein, were higher (p < 0.05) and sodium, albumin were significantly lower in the study group. The mean value of sodium, potassium, total bilirubin, alkaline phosphatase, serum glutamic-pyruvic transaminase, total protein and blood urea nitrogen, creatinine in two groups (<10 μg/dl and >10 μg/dl) was not significantly different. Serum glutamic-oxaloacetic transaminase level was significantly higher (p = 0.015) while albumin levels were significantly lower (p = 0.034) in >10 μg/dl group. A statistically significant correlation of BL levels with all haematological parameters was also observed. Creatinine is positively and albumin was negatively correlated with BL levels.

CONCLUSION

The outcomes specify that high BL levels were significantly associated with higher haematological and biochemical indices in exposed children. However, lead like noxious metals severely affected the haematological, kidney and liver health of children.

Development and optimization of heavy metal lead biosensors in biomedical and environmental applications

The detrimental impact of the heavy metal lead (Pb) on human health has been studied for years. The fact that Pb impairs human body has been established from countless painful and sad historical events. Nowadays, World Health Organization and many developmental countries have established regulations concerning the use of Pb. Measuring the blood lead level (BLL) is so far the only way to officially evaluate the degree of Pb exposure, but the so-called safety value (10 μg/dL in adults and 5 μg/dL in children) seems unreliable to represent the security checkpoint for children through daily intake of drinking water or physical contact with a lower contaminated level of Pb contents. In general, unsolved mysteries about the Pb toxicological mechanisms still remain. In this review article, we report on the methods to prevent Pb poison for further Pb toxicological research. We establish high-sensitivity Pb monitoring, and also report on the use of fluorescent biosensors such as genetically-encoded fluorescence resonance energy transfer-based biosensors built for various large demands such as the detection of severe acute respiratory syndrome coronavirus 2. We also contribute to the development and optimization of the FRET-based Pb biosensors. Our well-performed version of Met-lead 1.44 M1 has achieved a limit of detection of 10 nM (2 ppb; 0.2 μg/dL) and almost 5-fold in dynamic range (DR) supported for the real practical applications-that is, the in-cell Pb sensing device for blood and blood-related samples, and the Pb environmental detections in vitro. The perspective of our powerful Pb biosensor incorporated with a highly sensitive bio-chip of the portable device for quick Pb measurements will be addressed for further manipulation.

Effect of Encapsulated Lactobacillus bulgaricus on Innate Immune System and Hematological Parameters in Rainbow Trout (Oncorhynchus mykiss), Post-Administration of Pb

The present study was conducted to investigate the effects of probiotic and encapsulated Lactobacillus bulgaricus on hematological and immunological factors after lead toxicity in rainbow trout (Oncorhynchus mykiss). Two hundred and forty fish weighing about 16 ± 3.8 g were divided randomly in to four groups including two groups which were fed by a diet containing ~ 10⁸ CFU g^-1Lactobacillus bulgaricus and encapsulated Lactobacillus bulgaricus bacteria and also the third group diet without Lactobacillus bulgaricus. After 45 days, in addition to probiotic (~ 10⁸ CFU g^-1), 500 μg kg of lead nitrate was added to the food of the three groups for 21 days. The fourth group (control) was first fed to the normal diet for 45 days then exposed to Pb. Blood samples were collected at days 45, 52, 59, and 66, and hematological and some immunological parameters were assessed. Results showed that hemoglobin, red blood cells, white blood cells, and lysozyme activity in the two probiotics groups were increased significantly up to 45 day (P < 0.05), but followed by a decreasing trend by adding Pb. Complement and bactericidal activity were enhanced significantly in the bulgaricus group (P < 0.05). Respiratory burst activity at day 45 in group bulgaricus had significant increase (P < 0.05) and decreased in all groups particularly after Pb exposure (P < 0.05). The achieved data shows that microencapsulation of probiotics with alginate-chitosan may be a suitable method to improve the fish condition against heavy metal.

Assessment of Heavy Metal Contamination in Two Edible Fish Species and Water from North Patagonia Estuary

Estuaries worldwide have been severely degraded and become reservoirs for many types of pollutants, such as heavy metals. This study investigated the levels of Cd, Cu, Mn, Ni, Pb, and Zn in water and whole fish. We sampled 40 juvenile silversides Odontesthes regia and 41 juvenile puye Galaxias maculatus from the Valdivia River estuary, adjacent to the urban area in southern South America (Chile). Samples were analyzed using a flame atomic absorption spectrophotometer. In water samples, metals except Zn were mostly below the detection limits and all metals were below the maximum levels established by local guidelines in this estuary. In whole fish samples, concentrations of Cu, Zn, Pb, Mn, and Cd were significantly higher in puyes than in silversides. Additionally, Zn, Pb, and Mn were correlated to body length and weight in puyes, whereas Cd was correlated to body length in silversides. The mean concentration of heavy metals in silverside and puyes were higher than those reported in the literature. In silversides, all heavy metal levels were below the limits permitted by current legislation (FAO), whereas in puyes Pb and Cd levels were above the recommended maximum level established by international guidelines, therefore putting the human population at risk.

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.

Ameliorative and protective effects of fucoidan and sodium alginate against lead-induced oxidative stress in Sprague Dawley rats

The current study was performed to evaluate the possible protective effects of fucoidan (F) and sodium alginate (SA) against lead-induced oxidative damage in vivo, and to identify relevant underlying mechanisms. Health Sprague Dawley (SD) rats were divided into nine groups of ten rats each and treated orally with lead acetate (5 mg/kg, Pb2+) for 4 weeks, then gavaged with DMSA (Meso-2, 3-dimercaptosuccinic acid, 25 mg/kg), F (50, 100, 200 mg/kg) and SA (50, 100, 200 mg/kg) individually after successful modelling. We found that the administration of both F or SA resulted in a beneficial effect by significantly decreasing lead levels (p < 0.05) in the kidneys from 2.85 mg/kg to 0.79 mg/kg and improving antioxidant status (SOD, GSH, and CAT) thereby alleviating lead-induced damage and injury of the liver and kidneys (AST, BUN, and Cr). Both natural extracts exerted dose-dependent effects. Protective effects were further demonstrated by histopathology. Our results demonstrate that the F and SA are effective natural extracts for lead-eliminating, and that they can ameliorate oxidative damage induced by lead toxicity.

Intelligence gain and social cost savings attributable to environmental lead exposure reduction strategies since the year 2000 in Flanders, Belgium

BACKGROUND

Recent lead (Pb) exposure reduction strategies enabled to lower children's blood lead levels (B-Pb) worldwide. This study reports the estimated intelligence gain and social cost savings attributable to recent exposure reduction based on reported B-Pb levels observed in adolescents sampled within the framework of the Flemish Environment and Health Studies (FLEHS, Belgium), i.e. in 2003-2004 (FLEHSI), in 2008-2009 (FLEHSII), and in 2013-2014 (FLEHSIII).

METHODS

Intelligence Quotient (IQ) loss per 100,000 individuals - attributable to B-Pb above 20 μg/L - was estimated based on widely accepted dose response functions between children's B-Pb and IQ (- 1.88 IQ points for a duplication in B-Pb from 20 μg/L onwards; 95% Confidence Interval (CI): - 1.16;-2.59) and B-Pb exposure distribution parameters of FLEHS studies. The results were translated to the Flemish population of 15-year-olds. Given a 3-year time gap between subsequent sampling periods, the exposure distribution of each study was assumed 3 years prior to the study as well. Economic impact was estimated based on expected decrease in lifetime earnings (€ 19,464 per decreasing IQ point in 2018).

RESULTS

The percentage of the adolescent population exceeding a B-Pb of 20 μg/L decreased from 57% (FLEHSI) to 23% (FLEHSII), and even further to 2.5% (FLEHSIII). The estimated IQ loss per 100,000 individuals was 94,280 (95% CI: 58,427-130,138) in FLEHSI, 14,993 (95% CI: 9289-20,695) in FLEHSII, and 976 (95% CI: 604-1347) in FLEHSIII. This translates into a total loss of 378,962 (95%CI: 234,840-523,091) IQ points within the Flemish population of 15-year-olds between 2000 and 2014. Assuming that current exposure levels do not reincrease, the expected IQ loss during the subsequent period of 15 years is estimated to be maximally 10,275 (95%CI: 6363-14,182) points.

CONCLUSIONS

7176 (95%CI: 4447-9905) million € of social cost savings were achieved by Pb reduction strategies in Flanders over 15 years. If current exposure levels further reduce to B-Pb below 20 μg/L for the whole population, social cost savings may increase up to 7376 (95%CI: 4571-10,181) million €. Given the relatively low lead contamination in Flanders, the global impact of ongoing reduction strategies is expected to be tremendous.

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

BACKGROUND

Uncertainty remains regarding the association between blood lead levels (BLL) and serum uric acid (SUA) with relatively low BLL exposure because of limited data in the adolescent population. We examined the association between BLL and SUA in U.S. adolescents.

METHODS

In this cross-sectional study, 8303 adolescents aged 12-19 years from NHANES 1999-2006 were analyzed. BLL was Ln-transformed for analysis for the skewed distribution. Elevated SUA was defined as ≥5.5 mg/dL. Multivariate linear and multiple logistic regression analyses were performed to evaluate the association of BLL with SUA and elevated SUA. Moreover, a generalized additive model (GAM) and a fitted smoothing curve (penalized spline method) were conducted.

RESULTS

The overall mean BLL was 1.3 μg/dL. Multivariate linear regression analyses showed that LnBLL was independently and positively correlated with SUA level (β = 0.13, 95%CI: 0.09-0.17). Multiple logistic analyses showed that LnBLL was associated with a 24% increased prevalence of elevated SUA (OR = 1.24; 95% CI, 1.11-1.38). Analyses using restricted cubic spline confirmed that the associations of LnBLL with SUA and elevated SUA were linear. Subgroup analyses showed that stronger associations between LnBLL and SUA were detected in adolescents with lower levels of education and estimated glomerular filtration rate (eGFR) (all P for interaction < 0.05).

CONCLUSIONS

BLL was independently and positively correlated with SUA level and elevated SUA among U.S. adolescents, particularly with lower levels of education and eGFR. The data suggest that there is no "safe" threshold level of exposure to lead.

Toxicological effects in children exposed to lead: A cross-sectional study at the Colombian Caribbean coast

Lead (Pb) is an environmental pollutant with a toxicity that is a serious public health problem. The aim of this research was to evaluate the associations between Pb exposure and morphometric, hematological and biochemical parameters, mRNA expression of the P53, SOD1, ALAD, TNF and INF-γ genes, ALAD polymorphisms (db SNP ID: rs1800435) and Intelligence Quotient (IQ) in children from the Colombian Caribbean. Blood lead levels (BLL) were determined in 554 participants between the ages of 5-16 years old, from different places of the Colombian Caribbean. A health survey was given to assess risk factors. Whole blood was used for hematology and plasma employed to analyze markers of hepatic toxicity. Gene expression was quantified from blood mRNA by RT-PCR. The ALAD polymorphism was characterized by PCR-RFLP, and the Kaufman's brief intelligence test was employed to estimate the IQ. The mean BLL was 3.5 ± 0.2 μg/dL. The site of greatest exposure to Pb was Tasajera, a poor fishing community, with an average of 8.9 ± 0.8 μg/dL. Breastfeeding was associated with high BLL. Morphometric characteristics and IQ were negatively correlated with BLL. The blood platelet count and the mean corpuscular hemoglobin concentration showed positive and negative correlations with BLL, respectively. Negative relationships with BLL were observed with the ratios Neutrophils/Eosinophils and Neutrophils/Basophils, whereas for BLL and Neutrophils/Monocytes the association was positive. The associations between morphometric and some hematological parameters with BLL were age- and gender-related. The expression of ALAD, SOD1, INF-γ and P53 mRNA was down-regulated according to the BLL, whereas TNF showed an opposite trend. In short, fishing communities are at a high risk of Pb exposure. This xenobiotic can affect physical development and IQ, as well as hematological parameters, even at low concentrations. In addition, it can regulate the transcription of genes associated with inflammation, apoptosis, cell cycle, heme synthesis, and oxidative stress.

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

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

Assessing lead toxicity in the clam Ruditapes philippinarum: Bioaccumulation and biochemical responses

Lead (Pb) is a non-essential metal. Its occurrence in the environment is related principally to anthropogenic contamination. Pb is toxic to aquatic organisms and can provoke damage to membranes and inhibit the activity of essential enzymes. The filter-feeding, Manila clam Ruditapes philippinarum is widely used as a biomonitor organism to assess metal toxicity. Among biomarkers related to the Pb toxicity, the enzymatic activity of δ-aminolevulinic acid dehydratase (δ-ALAD) has been adopted as a specific tool. Metallothionein (MT), lipid peroxidation (LPO) and antioxidant enzymes activities, such as catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione S-transferase (GST) and superoxidase dismutase (SOD) have also been employed to assess the toxic effect of metals. Two target tissues, the gills and the digestive gland, were selected to examine biomarker responses. In order to assess the effects of Pb accumulation and the mechanisms involved in the recovery from it, clams were exposed at two Pb levels (10 and 100 µg/L) for 7 days and were later maintained in clean water for 7 days as a depuration period. Pb accumulation was dependent on the exposure concentration and higher Pb levels were observed in the gills compared to the digestive gland. Inhibition of δ-ALAD, GST and SOD and the induction of MT and LPO over the exposure period were observed in the gills and the digestive gland of R. philippinarum. The depuration period showed a continuous inhibition of the δ-ALAD activity and induction of MT and LPO in both tissues. These results demonstrate that lead induced an exposure effect and the 7 days of depuration were not sufficient to recover the basal health status of the clams.

Dose-response relationship between blood lead levels and hematological parameters in children from central China

BACKGROUND

Lead is a heavy metal that can affect the human hematological system. However, reports are limited on the dose-response relationship between blood lead levels (BLLs) and hematological parameters in children. This study aimed to explore the dose-response relationship between BLLs and hematological measurements among children in China.

METHODS

A cross-sectional design was used. A total of 743 children aged 5-8 years were recruited from two counties in central China. The BLLs and blood levels of iron, zinc, and calcium were determined, and hematological parameters were measured.

RESULTS

All hematological measurements and BLLs were logarithm-transformed to ensure a normal distribution. The geometric mean of the BLLs of all children was 82.4 μg/L. Forty-one percent of the children had BLLs ≥ 100 μg/L. The lead-poisoning percentages of the children were significantly associated with gender, age, district of residence, and environmental lead exposure level. Multivariate linear regression analyses showed no significant linear correlation between BLL and each hematological parameter among the children with BLLs ≥ 100 μg/L. The analyses also revealed a small increase in red blood cell count (RBC) with increasing BLLs in the BLLs < 100 μg/L group (β = 0.03, P =  0.048). A negative association was noted between BLLs and blood platelet (PLT) count in the children with BLLs < 100 μg/L (β = -0.90, P < 0.001). Logistic regression analyses showed that BLLs were significantly associated with decreased hemoglobin (Hb) levels, RBC counts, PLT counts and mean corpuscular hemoglobin (MCH) after adjusting for potential confounders. Such analyses also revealed a dose-response relationship between the BLLs and hematological parameters (Hb level, RBC count, and PLT count). The children with BLLs ≥ 100 μg/L were 2.72, 2.51, and 3.76 times more likely to achieve decreased RBC counts, Hb levels and PLT counts, respectively, compared to those with BLLs < 100 μg/L. Compared with children with BLLs < 100 μg/L, those with BLLs ≥ 100 μg/L were 3.16 and 4.38 times more likely to show decreased Hb levels and PLT counts respectively in the high-level lead-exposure group and 4.33 times more likely to achieve a decreased PLT count in the low-level lead-exposure group. The individuals with BLLs of the highest quartile were 3.65, 5.87, and 29.23 times more likely to exhibit decreased Hb levels, RBC counts, and PLT counts, respectively, than the children with BLLs of the lowest quartile.

CONCLUSION

Our findings suggested a negative association between BLLs and hematological indicators (Hb level, RBC count, PLT count and MCH). A strong negative, non-linear dose-response relationship was also showed between BLLs and hematological parameters (Hb level, RBC count, and PLT count).

Lead exposure is associated with risk of impaired coagulation in preschool children from an e-waste recycling area

Environmental lead exposure leads to various deleterious effects on multiple organs and systems, including the hematopoietic system. To explore the effects of lead exposure on platelet indices in preschool children from an informal, lead-contaminated electronic waste (e-waste) recycling area, we collected venous blood samples from 466 preschool children (331 from an e-waste area (Guiyu) and 135 from a non-e-waste area (Haojiang)). Child blood lead levels (BLLs) were determined by graphite furnace atomic absorption spectrophotometry, while platelet indices were quantified using a Sysmex XT-1800i hematology analyzer. Higher blood lead levels are observed in e-waste lead-exposed preschool children. Significant relationships between high blood lead levels (exceeding current health limits) and elevated platelet count (PLT), plateletcrit (PCT), mean platelet volume (MPV), and platelet large cell ratio (P-LCR) were also uncovered. Furthermore, the median PLT and PCT levels of children from the exposed group both exceeded the respective recommended maximum reference range value, whereas the reference group did not. Location of child residence in Guiyu and BLLs were both risk factors related to platelet indices. These results suggest that high blood lead exposure from e-waste recycling may increase the risk of an amplified coagulation process through the activation of platelets in preschool children.

Low blood lead levels impair intellectual and hematological function in children from Cartagena, Caribbean coast of Colombia

Lead produces numerous biochemical and physiological changes in humans, including hematological disorders, toxic effects on the central nervous system and in the function of several organs. The aim of this study was to determine blood lead levels (BLL) in children from Cartagena, Colombia, associating those with hematological and liver damage markers, the intelligence quotient (IQ), as well as with gene expression of the aminolevulinate dehydratase (ALAD), superoxide dismutase 1 (SOD1), gamma interferon (INF-γ), tumor necrosis factor (TNF) and tumor protein (p53). To achieve this purpose, 118 blood samples were collected from children 5-16 years old, with their respective informed consent from their parents. BLL was measured by atomic absorption; hematological parameters were obtained with automated systems; plasma was utilized to analyze hepatic toxicity markers, alanine aminotransferase (ALT), gamma-glutamyltransferase (γ-GT) and alkaline phosphatase (ALP); the Kaufman Brief Intelligence Test (K-BIT) was administered to measure the IQ; and gene expression was quantified from blood RNA. The mean BLL was 1.7±0.3μg/dL. A low proportion of the children (3.4%) had BLL above the CDC recommended limit (5μg/dL). BLL were correlated weakly, but negatively with child age, weight, height, body mass index, platelets wide distribution, mean platelet volume, γ-GT and IQ. There were not significant changes in the expression of evaluated genes. These results support the hypothesis that BLL below 5μg/dL may still be a detrimental factor on children's cognitive abilities, development and hematology, in line with recent concerns that there is no safe level of pediatric lead exposure.

Exposure to Low Levels of Lead in Utero and Umbilical Cord Blood DNA Methylation in Project Viva: An Epigenome-Wide Association Study

BACKGROUND

Early-life exposure to lead is associated with deficits in neurodevelopment and with hematopoietic system toxicity. DNA methylation may be one of the underlying mechanisms for the adverse effects of prenatal lead on the offspring, but epigenome-wide methylation data for low levels of prenatal lead exposure are lacking.

OBJECTIVES

We investigated the association between prenatal maternal lead exposure and epigenome-wide DNA methylation in umbilical cord blood nucleated cells in Project Viva, a prospective U.S.-based prebirth cohort with relatively low levels of lead exposure.

METHODS

Among 268 mother-infant pairs, we measured lead concentrations in red blood cells (RBC) from prenatal maternal blood samples, and using HumanMethylation450 Bead Chips, we measured genome-wide methylation levels at 482,397 CpG loci in umbilical cord blood and retained 394,460 loci after quality control. After adjustment for batch effects, cell types, and covariates, we used robust linear regression models to examine associations of prenatal lead exposure with DNA methylation in cord blood at epigenome-wide significance level [false discovery rate (FDR)<0.05].

RESULTS

The mean [standard deviation (SD)] maternal RBC lead level was 1.22 (0.63) μg/dL. CpG cg10773601 showed an epigenome-wide significant negative association with prenatal lead exposure (-1.4% per doubling increase in lead exposure; p=2.3×10-7) and was annotated to C-Type Lectin Domain Family 11, Member A (CLEC11A), which functions as a growth factor for primitive hematopoietic progenitor cells. In sex-specific analyses, we identified more CpGs with FDR<0.05 among female infants (n=38) than among male infants (n=2). One CpG (cg24637308), which showed a strong negative association with prenatal lead exposure among female infants (-4.3% per doubling increase in lead exposure; p=1.1×10-06), was annotated to Dynein Heavy Chain Domain 1 gene (DNHD1) which is highly expressed in human brain. Interestingly, there were strong correlations between blood and brain methylation for CpG (cg24637308) based on another independent set of samples with a high proportion of female participants.

CONCLUSION

Prenatal low-level lead exposure was associated with newborn DNA methylation, particularly in female infants. https://doi.org/10.1289/EHP1246.

Elevated lead levels and changes in blood morphology and erythrocyte CR1 in preschool children from an e-waste area

Improper dismantling and combustion of electronic waste (e-waste) may release persistent organic pollutants and heavy metals that possess potential risk for human health. Lead (Pb) is carried through the circulatory system by erythrocytes and is known to alter the functions of hematopoietic and immune systems. The aim of the study was to investigate the effect of Pb exposure on blood morphology and erythrocyte complement receptor 1 (CR1) levels as related to immunologic function in preschool children. We recruited 484 preschool children, 2- to 6-years of age, among whom 332 children were from Guiyu, a typical and primitive e-waste processing area, and 152 children from Haojiang (reference area). Results showed that the blood Pb level (BPb) and erythrocyte Pb level (EPb) of exposed children were significantly higher, but, the mean corpuscular hemoglobin concentration (MCHC) and erythrocyte CR1 levels were significantly lower than reference children. Elevated EPb and BPb was related to disadvantageous changes in hematocrit (HCT), mean corpuscular volume (MCV), hemoglobin (HGB), mean corpuscular hemoglobin (MCH), and MCHC, respectively, in children from the e-waste recycling area. Furthermore, in the high Pb-exposed group, the Pb toxicity of erythrocytes was more significant compared to the low Pb-exposed group in e-waste-exposed children. Combine with the BPb and EPb would be better to evaluating the Pb toxicity of erythrocytes. Compared to low Pb exposure, high BPb and EPb were associated with lower erythrocyte CR1 expression in all children. Our data suggests that elevated Pb levels result in adverse changes in blood morphology, hemoglobin synthesis and CR1 expression, which might be a non-negligible threat to erythrocyte immunity development in local preschool children. It is therefore imperative for any intervention to control the Pb exposure of children and actively educate adults to raise their environmental awareness of potential e-waste pollution during the recycling process.

Toxic effects on bioaccumulation and hematological parameters of juvenile rockfish Sebastes schlegelii exposed to dietary lead (Pb) and ascorbic acid

Juvenile rockfish, Sebastes schlegelii (mean length 11.3 ± 1.2 cm, and mean weight 32.5 ± 4.1 g) were exposed for four weeks to dietary lead (Pb²⁺) at 0, 120, and 240 mg/L and ascorbic acid (AsA) at 100, 200, and 400 mg/L. The exposure concentrations and duration of significant Pb-induced accumulations in specific tissues of S. schlegelii were assessed. High levels of ascorbic acid significantly attenuated accumulations following exposure to dietary Pb. Dietary Pb exposure caused a significant increase in blood Pb concentrations, whereas red blood cell (RBC) count, hematocrit, and hemoglobin were significantly decreased. Notable changes were also observed in plasma calcium, magnesium, glucose, cholesterol, glutamic oxaloacetic transaminase (GOT), and glutamic pyruvate transaminase (GPT). The growth performance of S. schlegelii was significantly decreased. High doses AsA supplemention were effective in attenuating the changes brought about by dietary Pb exposure.

Should all patients with unexplained anaemia be screened for chronic lead poisoning?

The global prevalence of lead poisoning is declining. However, the prevalence of lead poisoning in patients with either microcytic or normocytic anaemia is unknown. Blood samples from anaemic patients residing in south-east London without an obvious cause for anaemia had their blood lead concentration (BLC) analysed.A batch of 988 samples was analysed for BLC using atomic absorption spectroscopy. Median haemoglobin was 10.3 g/dL (range: 4.2–10.9) in females, 10.6 g/dL (range: 5.2–11.4) in males and 10.7 g/dL (range: 6.7–10.9) in children. Median BLC was 2.63 μg/dL (0.21–24.0 μg/dL; 95th centile 7.54 μg/dL). Fifteen samples (1.5%) had a BLC>10.0 μg/dL, five samples (1%)>15.0 μg/dL and one sample (0.1%)>20.0 μg/L. In the 106 children, median BLC was 2.34 μg/dL (0.5–14.5 μg/dL; 95th centile 6.12 μg/ dL). Only one child (14.5 μg/L) had a BLC>10.0 μg/dL. There was a poor correlation between haemoglobin and BLC (r2=0.08).Routine screening for lead poisoning cannot be justified in all patients with unexplained anaemia, unless there is a history or clinical features to suggest lead toxicity. Additionally, we have shown that in this former high-risk area for lead exposure, there is a low point prevalence of significant lead poisoning, even in an anaemic population.

Association between Blood Lead Levels and Age-Related Macular Degeneration

Purpose

To investigate the association between blood lead levels and prevalence of age-related macular degeneration (AMD).

Methods

A nationwide population-based cross-sectional study included 4,933 subjects aged over 40 years who participated in the 2008–2012 Korean National Health and Nutrition Examination Survey, and for whom fundus photographs were available. All participants underwent a standardized interview, evaluation of blood lead concentration, and a comprehensive ophthalmic examination. Digital fundus photographs (45°) were taken of both eyes under physiological mydriasis. All fundus photographs were graded using an international classification and grading system.

Results

Mean blood lead levels were 3.15 μg/dL in men and 2.27 μg/dL in women (P < 0.001). After adjusting for potential confounders including age, gender, smoking status, total cholesterol levels, triglyceride levels, heart problems and strokes, the adjusted odds ratio (OR) in women for any AMD was 1.86 (95% Confidence Interval [CI], 1.03–3.36) and for early AMD was 1.92 (95% CI, 1.06–3.48), for those in the highest quintile of lead level compared with the lowest quintile. In men, however, blood lead level was not significantly associated with AMD.

Conclusions

Blood lead levels were higher in men, but were only associated with AMD in women. Increased levels of blood lead may be involved in the pathogenesis of AMD development in women.

Lead in school children from Morelos, Mexico: levels, sources and feasible interventions

Background: Lead is a pervasive pollutant, associated at low levels to many adverse health effects. Objective: To investigate lead levels, exposure pathways and intervention possibilities in school children from Alpuyeca, in Morelos, Mexico. Methods: Blood lead concentrations (BPb) were measured in 226 children in 2011. Exposure pathways were assessed through a questionnaire, lead measurements in different environmental matrices and spatial aggregation analysis of lead concentrations. Results: BPb ranged from 1.5 to 36.5 µg/dL, with a mean (SD) of 7.23 (4.9) µg/dL. Sixty-four and 18% of the children had BPb > 5 µg/dL and > 10 µg/dL, respectively. The use of lead glazed ceramics was reported in almost half of the households; it was the main BPb determinant and it was associated with an increased risk of having BPb > 5 g/dL by 2.7 times (p = 0.001). Environmental samples were within US EPA’s lead recommended limits, and blood lead levels were randomly distributed in the community. Conclusions: Lead remains a public health problem in Alpuyeca, Mexico. Unlike other local pollutants, lead exposure prevention can be achieved inexpensively and in a short term. Interventions should make mothers aware of lead’s health effects and empower them to safeguard their children’s health by avoiding the culturally ingrained use of lead glazed pottery.

Association between blood erythrocyte lead concentrations and hemoglobin levels in preschool children

Despite decades of intensive research, lead (Pb) toxicity still remains one of the most frequently investigated subjects in environmental health. Whole blood lead (BPb) is usually used to evaluate Pb exposure for both screening and clinical diagnosis. However, it is generally recognized that BPb is not a sensitive biomarker for Pb exposure in hematological studies. Considering hematocrit (HCT) variation in different situations, HCT-adjusted BPb or erythrocyte Pb (EPb) may be more relevant when evaluating the hematotoxicity of blood Pb. Data collected from 855 preschool children, 3-7 years of age, allowed us to examine the relationship between EPb and hemoglobin (Hb) levels. Multivariate linear regression was performed to determine the significance of EPb as predictor of Hb after covariate adjustment; then, mean differences of Hb levels between quartiles of EPb and BPb (1st quartile as reference) were determined using ANOVA followed by Student's t test. The dose-response curve between EPb and HCT was plotted using locally weighted scatterplot smoothing (LOWESS) method. A doubling of EPb was associated with a 2.44 g/L decrease in Hb level. Compared to the 1st quartile group of EPb, the 3rd and 4th quartile groups showed significant decreases in Hb levels (3.01 and 3.97 g/L, respectively). Compared to the 1st quartile group of BPb, the 2nd quartile group showed a decrease in Hb levels (0.63 g/L), while the 3rd and 4th quartile groups showed increases in Hb levels (0.78 and 1.45 g/L, respectively). Increased EPb levels are significantly associated with decreased Hb levels in preschool children. HCT must be taken into consideration in investigating the hematological effects of Pb. Compared to BPb, EPb or HCT-adjusted BPb appear as a more effective biomarker to interpret the hematotoxicity of lead. Furthermore, blood erythrocytes are not only a repository of Pb but also a primary target of its toxicity.

Amino siloxane oligomer-linked graphene oxide as an efficient adsorbent for removal of Pb(II) from wastewater

A high performance sorbent, oligomer-linked graphene oxide (GO) composite, was prepared through simple cross-linking reactions between GO sheets and poly3-aminopropyltriethoxysilane (PAS) oligomers as crosslinking agents. The three-dimensional PAS oligomers prevented GO sheets from aggregation, provided foreign molecules with easier access, and introduced a large amount of amino functional groups. The morphology, structure and property of the PAS-GO composite were determined by scanning electron microscope (SEM), transmission electron microscope (TEM), Fourie transform infrared (FTIR), X-ray diffractometer (XRD), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The adsorption performance of PAS-GO was investigated in removing Pb(II) ions from water. Compared to 3-aminopropyltriethoxysilane functionalized GO (AS-GO) which was prepared by the direct reaction between 3-aminopropyltriethoxysilane and GO, PAS-GO exhibited much higher adsorptivity toward Pb(II) with the maximum adsorption capacity of 312.5mg/g at 303 K and furthermore the maximum adsorption capacity increased with increasing temperature. The adsorption could be conducted in a wide pH range of 4.0-7.0. Importantly, PAS-GO had a priority tendency to adsorb Pb, Cu and Fe from a mixed solution of metal ions, especially from a practical industrial effluent.

Changes in blood metals, hematology and hepatic enzyme activities in lactating cows reared in the vicinity of a lead-zinc smelter

The present study examines blood metals levels and health parameters in dairy cows reared in areas around a Pb-Zn industrial complex located near the city of Zanjan-Iran. Blood samples (n = 27) were collected from cows reared around the smelter. Blood samples (n = 25) were also collected from cows reared in areas where chances of Pb contamination of soil, water and fodder do not exist, to serve as reference. The mean blood Pb level in cows around the smelter (1.09 ± 0.26 µg/mL) was higher than the cows from the reference area (0.72 ± 0.25 µg/mL). Hematocrit (PCV) levels decreased in cows reared in the near of smelter (24.37 % ± 2.22 %) compared to the reference site (27.54 % ± 2.87 %). Hemoglobin (Hb) concentration and mean corpuscular Hb concentration value in cows from the area around the smelter were statistically lower than the cows reared in reference area. Activities of alanine transaminase and aspartate aminotransferase (IU/l) were significantly higher in cows around the smelter as compared to reference animals.

Adipose tissue: another target organ for lead accumulation? A study on Sardinian children (Italy)

OBJECTIVES

This study analyzes the relationship between lead levels and adipose tissue in Sardinian children. As an environmental pollutant, lead occurs in two different chemical forms: inorganic and organic lead; organic lead is present in the environment mainly as lead-alkyls (tetramethyl and tetraethyl lead). The lead-alkyls are characterized by their liposolubility; because of this characteristic, the behavior of organic Pb in the organism is similar to that of persistent organic pollutants (POPs). In fact, the high liposolubility of POPs, synthetic chemical substances highly resistant to biodegradation in both the environment and the human body, gives them a preferential tendency to accumulate in adipose tissue.

METHODS

The study sample consisted of 759 children between 11 and 15 years resident in various municipalities of Sardinia. Hair lead levels (PbH) were used as the biomarker of exposure, while several anthropometric indexes were adopted to evaluate the adipose tissue: weight, body mass index, waist circumference, waist to hip circumference ratio, and sum of skinfolds (Σskf).

RESULTS

The results of the multivariate ridge regression analysis, controlling for sex and age, show a significant positive relationship between logPbH and logΣskf but not the other adiposity indicators.

CONCLUSIONS

This results suggests that organic lead tends to accumulate in adipose tissue, although it would be appropriate to measure lead levels in the adipose tissue itself in order to verify the results. Hence this tissue could be considered a possible new biological matrix for the evaluation of environmental lead exposure.

Correlation between total blood lead values and peripheral blood counts in workers occupationally exposed to urban stressors

The aim of the study was to assess the relationship between occupational exposure to airborne lead (Pb) and alterations in peripheral blood counts in workers of the Municipal Police assigned to different types of outdoor tasks. Then, 337 both male and female subjects were enrolled and divided on the basis of sex, cigarette smoking habit and kind of task. Exposure to airborne Pb, dosage of total blood Pb and peripheral blood count were carried out. A significant positive correlation was detected between the values of total blood Pb and values of plasma reticulocytes (%RET) both in the total sample and for all the classes of the subdivision except for police drivers. Some statistically significant correlations were present but discontinuous for other variables of peripheral blood counts. Results suggest that occupational exposure to low doses of airborne Pb is able to influence lines of the hematopoietic system in exposed workers, with special reference to %RET.

Blood lead level and its relationship to certain essential elements in the children aged 0 to 14 years from Beijing, China

OBJECTIVE

To investigate blood lead level and its relationship to copper, zinc, calcium, magnesium and iron in the children aged 0 to 14 years old from Beijing, China.

METHODS

We classified 3181 children into one of the four groups: Group A (n=783, <1 year old); Group B (n=1538, 1-3 years old); Group C (n=443, 3-7 years old); and, Group D (n=417, 7-14 years old). All these metal elements were determined by atomic absorption spectrometry.

RESULTS

The blood lead level was 0.207±0.105 μmol/L. There was a significant gender difference for zinc (P<0.05) in Group C, and there was also a significant gender difference for copper (P<0.05) and lead (P<0.05) in Group D. Controlling for gender and age, we observed that there was a negative correlation of lead with zinc (r=-0.052, P<0.01), magnesium (r=-0.042, P<0.05) and iron (r=-0.031, P<0.05), respectively. Furthermore, in the children aged 1-7 years old, we also found there was a negative linear correlation of lead with zinc, magnesium and iron, respectively (P<0.01).

CONCLUSION

Blood lead level in children from Beijing was markedly decreased. And deficiency of zinc, magnesium and iron is related to the elevated blood lead level in the children aged 1-7 years.

Environmental lead exposure as a risk for childhood aplastic anemia

Concern about environmental lead exposure as a significant public health threat has increased as evidence has accumulated regarding adverse health effects at successively lower levels. Aplastic anemia is a hematological disorder of unknown etiology with a high lethality rate. Lead is a known toxicant for the hematopoietic system. Oxidative stress appears to be the possible mode of lead toxicity. We evaluated the effects of blood lead level on oxidative stress parameters in children suffering from aplastic anemia disease. Seventeen children with aplastic anemia disease (15 male and 2 female, age 3-12 y) were recruited in the study group. Fifty one healthy children (45 male and 6 female, age 3-12 y) having normal blood profiles and not suffering from any chronic disease(s) were used as controls. Blood lead level and oxidative stress parameters were determined. Mean blood lead level was significantly higher while δ-aminolevulinic acid dehydratase (δ-ALAD) activity, a biomarker for lead exposure was significantly lower in the study group as compared to the control group (p < 0.05 for each). Thiobarbituric acid reactive species (TBARS), a marker of lipid peroxidation, was significantly higher while the antioxidant glutathione (GSH) level was significantly lower in the study group as compared to the control group (p < 0.05 for each). Activity of the antioxidant enzyme catalase (CAT) was significantly higher in the study group than in the control group (p < 0.05). There was a significant negative correlation of blood lead levels with δ-ALAD (r = -0.45; p < 0.05) and GSH (r = -0.32; p < 0.05), and a positive correlation with TBARS (r = 0.41; p < 0.05) and CAT (r = 0.37; p < 0.05). Although a causal pathway cannot be determined from this study, our results indicated that lead induces oxidative stress in children suffering from aplastic anemia. Lead-induced oxidative stress as an underlying mechanism for aplastic anemia warrants further research.

Blood lead levels in children of Lucknow, India

After implementing measures to control lead pollution in many countries, blood lead levels (BLLs) in children have been declined. The phase-out of leaded petrol began in Lucknow, the capital of most populated state, Uttar Pradesh in India on April 1, 2000. We evaluated the mean BLL and associated risk factors for lead exposure in Lucknow children (3-12 years) after petrol lead phase-out activity. The mean BLL of the 200 children was 9.3 microg/dL (range: 1.0-27.9 microg/dL). Seventy-four children (37%) had BLL above the Centre for Disease Control and Prevention's (CDC) level of concern (10 microg/dL). When these data were compared with BLLs determined by the George Foundation among the children of Mumbai, Bangalore, Kolkata, Chennai, Hyderabad, and Delhi during the year 1997 when leaded petrol was in use, where 62%, 62%, 87%, 96%, 43%, and 95%, respectively, then exceeded the CDC intervention level. Further, BLL of present study was very close to Mumbai children (age < or =12 years) estimated following the introduction of unleaded petrol, and 33% children had BLL above the CDC concern level with an average 8.4 microg/dL. Low socioeconomic status, proximity of home to traffic density, and mother's illiteracy were the factors associated with elevated BLLs in Lucknow children (P < 0.05). Overall, results indicate a declining trend of BLL in Lucknow children when compared with those reported from other cities of India when leaded petrol was in practice. A national population-based study is recommended to determine the prevalence of elevated BLLs after the phase-out of leaded-petrol. In addition, future studies on other sources of lead exposure in Lucknow are warranted for public health purposes.

Estimation of Polish cigarettes contamination with cadmium and lead, and exposure to these metals via smoking

To estimate exposure to cadmium (Cd) and lead (Pb) through cigarette smoking, the concentrations of both metals in the blood or/and urine of smokers (20 cigarettes or more per day for 10 years or longer) and their non-smoking counterparts inhabiting an environmentally unpolluted area (Bialystok, Poland) were evaluated, as well as Cd and Pb contents in the cigarette brands (produced in Poland) smoked by the participants, including intact cigarettes, pre-smoking (tobacco, paper and filter) and post-smoking (butt, ash and smoke) cigarette components. Blood and urinary Cd concentrations in the smokers have been already reported by us to be 2-4 times higher than in the non-smokers (Galazyn-Sidorczuk et al. Polish Journal of Environmental Studies, 13 (Suppl.1):91-95, 2004). All the other measurements are the subject of the present paper. Pb concentration in the blood of the cigarette smokers (52.12 +/- 15.51 microg l(-1)) was higher by 29% than in the non-smokers (40.42 +/- 11.19 microg l(-1)). The mean Cd and Pb contents in the cigarettes were 0.6801 +/- 0.1765 and 0.6853 +/- 0.0746 microg per cigarette, respectively. Under cigarette burning, performed using a machine for self-acting burning, on average 33% of Cd and 11% of Pb present in the whole cigarette was released into the smoke. For Cd, unlike Pb, there was a high positive correlation between the metal content in cigarettes and tobacco and its release into the smoke. Moreover, the subjects smoking cigarettes containing the highest Cd amount had higher blood Cd concentration than smokers of other cigarette brands. The results give clear evidence that in the case of inhabitants of areas unpolluted with Cd and Pb habitual cigarette smoking, due to tobacco contamination, creates a serious source of chronic exposure to these metals, especially to Cd.

Antioxidant enzymes activities and bilirubin level in adult rat treated with lead

Lead toxicity is closely related to its accumulation in several tissues and its interference with bioelements, whose role is critical for several biological processes. Recently, oxidative stress has been proposed as a possible mechanism involved in lead toxicity. This study was carried out to investigate the effect of dose-dependent lead exposure on haematological and oxidative stress parameters. Adult male 'Wistar' rats (150-200 g) were divided into three groups: group [Pb 5] and group [Pb 15] received respectively 5 mg Pb(2+) (n=16) and 15 mg Pb(2+)/kg b.w. (n=16) as lead acetate solution i.p. for a period of seven days. Group [T] (n= 16) served as control and received 15 mg Na(+)/kg b.w. as sodium acetate solution i.p. for the same period. All animals were sacrificed 24 h after the last injection. Blood superoxide dismutase (SOD) and blood glutathione peroxidase (GPx) activities and plasma bilirubin level were measured. Liver was quickly excised for the estimation of alteration in lipid peroxidation indices (MDA). Lead exposure induces, in both treated groups, a marked decline in haematocrit and haemoglobin levels (p<0.01) when compared to control. The results show also a significant decrease (p<0.01) in SOD activity, but only in group [Pb 15]. SOD activity did not decrease in group [Pb 5] in comparison with control (p>0.05). However, lead exposure caused a light increase in GPx activity in group [Pb 15], which remains non-significant (p>0.05) compared to control. Group [Pb 5] did not record significant changes in the activity of GPx. Lead exposure for a period of seven days resulted in a significant (p<0.05) increase in bilirubin level in group [Pb 15] compared to control. The bilirubin level from rats of group [Pb 5] did not reach a statistical significance. Changes in liver MDA content in lead-exposed rats from [Pb 5] and [Pb 15] groups did not reach a statistical (p<0.05) significance. It is concluded that lead induces oxidative stress in a dose-dependent manner. No dose-dependent response was observed in blood GPx activity and liver MDA content. These results could be due to the short duration of the treatment.

Low level lead exposure and oxidative stress: Current opinions

Lead continues to pose a serious threat to the health of many children as well as adults. Concern about lead exposure as a significant public health problem has increased as evidence has mounted regarding adverse health effects at successively lower levels. This issue is complicated by the fact that there is no demonstrated biological function of lead in human. Lead potentially induces oxidative stress and evidence is accumulating to support the role of oxidative stress in the pathophysiology of lead toxicity. Lead is capable of inducing oxidative damage to brain, heart, kidneys, and reproductive organs. The mechanisms for lead-induced oxidative stress include the effects of lead on membranes, DNA, and antioxidant defense systems of cells. Recent epidemiological and toxicological studies have reported that lead exposure causes several diseases including hypertension, kidney disease, neurodegenerative disease and cognitive impairment. Although all these diseases include components of oxidative stress, the relevance of oxidative stress to lead-related diseases with low lead exposure has been criticized because most of the mechanistic studies have been conducted at moderate to higher dose levels. The association between low level lead exposure and oxidative stress has not been explored systematically. The present review focuses on mechanisms for lead-induced oxidative stress and relevance of oxidative stress to lead-related human disease with low lead exposure.

Interaction of lead with some essential trace metals in the blood of anemic children from Lucknow, India

BACKGROUND

The effects of lead on the hematological system results in the inhibition of heme synthesis and in anemia. Lead may affect the absorption and metabolism of essential trace metals also. There is little information especially from the northern region of India regarding the relationship between blood lead levels>or=10 microg/dl and anemia in children. We performed a cross-sectional study to evaluate the association of blood lead levels>or=10 microg/dl with anemia, and its effect on hematological system and some essential trace metals in children.

METHODS

A total of 75 children aged 1-7 years, 50 anemic (Hb<or=8 g%) and 25 non-anemic (Hb>8 g%), drawn from Lucknow, India and nearby areas were recruited to determine blood levels of lead, iron, zinc, copper, and calcium along with hematological parameters [delta-aminolevulinic acid dehydratase (delta-ALAD) hemoglobin (Hb), hematocrit, and ascorbic acid].

RESULTS

Based on Centre for Disease Control and Prevention's intervention level of blood lead, children were categorized into those with blood lead<10 microg/dl (6.89+/-2.44) (n=19) (GI) and those with blood lead<10 microg/dl (21.86+/-7.58) (n=56) (GII). After adjustment for child's age, sex, and area of residence, children with blood lead levels>or=10 microg/dl were 2.87 (95% CI: 1.60-2.87) times as likely to have anemia as children with blood lead levels<10 microg/dl. The differences of the adjusted mean values of Hb, delta-ALAD, and hematocrit were significantly lower in children from the GII group when compared to children from the GI group (p<0.01, p<0.01, and p<0.05, respectively). Among essential trace metals, adjusted mean levels of blood iron, zinc, and calcium were significantly lower in GII as compared to GI (P<0.05 each). There were significant negative correlations of blood lead levels with delta-ALAD (r=-0.612, p<0.01), hematocrit (r=-0.427, p<0.05), iron (r=-0.552, p<0.05) zinc (r=-0.427, p<0.05), and calcium (r=-0.324, p<0.05).

CONCLUSION

Results indicate that elevated blood lead levels (>or=10 microg/dl) in children were significantly associated with risk of anemia and that blood lead levels also influenced the status of essential trace metals. However, results of this study may be limited due to limited sample size but certainly form the basis of a larger sample size study, taking into account all the known potential confounders of anemia in children.