Perspectives on lead toxicity

A Halloysite Nanotubes-based Probe for Efficient Fluorescence Detection and Adsorption Removal of Pb2+ in Water

The detection and removal of Pb2+ is of utmost importance for environmental protection and human health due to its toxicity, persistent pollution, and bioaccumulation effects. To address the limitations associated with organic small molecule-based fluorescence probes such as poor water solubility and single functionality in detecting Pb2+, a fluorescence probe based on halloysite nanotubes was developed. This probe not only enables specific, rapid, and reliable detection of Pb2+ but also facilitates efficient removal of it from water. The development of this bifunctional fluorescent probe provides a valuable insight for designing more advanced probes targeting heavy metal ions.

Microfluidics in environmental analysis: advancements, challenges, and future prospects for rapid and efficient monitoring

Microfluidic devices have emerged as advantageous tools for detecting environmental contaminants due to their portability, ease of use, cost-effectiveness, and rapid response capabilities. These devices have wide-ranging applications in environmental monitoring of air, water, and soil matrices, and have also been applied to agricultural monitoring. Although several previous reviews have explored microfluidic devices' utility, this paper presents an up-to-date account of the latest advancements in this field for environmental monitoring, looking back at the past five years. In this review, we discuss devices for prominent contaminants such as heavy metals, pesticides, nutrients, microorganisms, per- and polyfluoroalkyl substances (PFAS), etc. We cover numerous detection methods (electrochemical, colorimetric, fluorescent, etc.) and critically assess the current state of microfluidic devices for environmental monitoring, highlighting both their successes and limitations. Moreover, we propose potential strategies to mitigate these limitations and offer valuable insights into future research and development directions.

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.

Heavy metals contamination of seafood from the crude oil-impacted Niger Delta Region of Nigeria: A systematic review and meta-analysis

This study aims at computing the pooled mean estimate (PME) and health risks of heavy metals in seafood obtained from the Niger Delta Region of Nigeria (NDRN), using data from existing literatures. Pubmed, Scopus and Google Scholar were searched to retrieve articles that investigated the heavy metal contents of edible seafood from the NDRN. Search hits were screened against predetermined criteria following which relevant data were extracted from eligible articles. The PME for each metal was computed by performing a maximum likelihood random effect model meta-analysis using the R Studio Software. Outcome from the meta-analysis involving 58 studies and a total of 2983 seafood samples revealed the following PMEs (mg/kg dry wt seafood) for the investigated heavy metals: As (0.777), Cd (0.985), Co (4.039), Cr (2.26), Cu (11.45), Fe (143.39), Hg (0.0058), Mn (13.56), Ni (5.26), Pb (4.35), and Zn (29.32). The health risk assessment suggests that seafood from this region poses considerable carcinogenic and non-carcinogenic risks to human consumers. Our finding calls for urgent actions aimed at identifying and eliminating point sources of heavy metals pollution of the NDRN marine environment. Inhabitants of NDRN are encouraged to reduce seafood consumption while diversifying their protein sources to include non-seafood options.

Seasonal variation, contribution and dynamics of trace elements in the drainage basin and estuary of the Serinhaém river, BA

In the present study a mass balance calculation was used to quantify trace elements (Al, Ba, Cd, Cr, Cu, Fe, Mn, Pb, Ti, V and Zn) fluxes exported from the Serinhaém River estuary to the Atlantic Ocean. The studied elements exportation in the particulate fraction showed higher fluxes in the first sampling campaign and a high export rate to the Atlantic Ocean during this period. The physical-chemical parameters showed the highest values in sampling campaign 1. These variations are probably the cause of the different trace elements behavior in fluvial and estuarine areas, where removal and addition processes between particulate and dissolved phases took place, affecting distribution coefficient and fluxes to the Atlantic Ocean. EPA ecosystems present values in accordance with Brazilian legislation for pristine areas, however, monitoring programs must be carried out in the region, to avoid future environmental problems.

Protective Effect of 3-Benzoyl-7-Hydroxy Coumarin on Lipid Peroxidation and Minerals on Rat Liver Tissues Induced Oxidative Stress with Lead Acetate

Lead is a toxic substance and damages human metabolism. Coumarin-derived substances have many effects such as antioxidant, anticancer, and antibacterial ones. In this study, the effects of 3-benzoyl-7-hydroxy coumarin on rat liver tissues under oxidative stress with lead acetate were investigated. In the study, rats were divided into 4 groups. Control group (K), Coumarin group (KUM), Lead acetate group (P) and Coumarin+Lead acetate group (KUMP) groups were formed. Malondialdehyde (MDA), lead (Pb), iron (Fe), zinc (Zn), manganese (Mn), and copper (Cu) levels were determined in the liver tissues of the rats. MDA level of P group increased compared to the other groups. A decrease was observed in the KUMP group compared to the P group MDA level. While the Pb and Fe levels of the P group increased compared to the K group, the Pb and Fe levels of the KUMP group decreased compared to the P group. As a result, it is concluded that the 3-benzoyl-7-hydroxy coumarin molecule protects the high lipid peroxidation, lead, and iron metabolism caused by lead acetate in the liver.

CuAAC-Derived Selective Fluorescent Probe as a Recognition Agent for Pb(II) and Hg(II): DFT and Docking Studies

Copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) is a resourceful and stereospecific methodology that has considerably yielded promising 1,2,3-triazole-appended "click" scaffolds with the potential for selective metal ion recognition. Based on "click" methodology, this report presents a chemosensor probe (TCT) based on 4-tert-butylcatechol architecture, via the CuAAC pathway, as a selective and efficient sensor for Pb(II) and Hg(II) ions, categorized as the most toxic and alarming environmental contaminants among the heavy metal ions. The synthesized probe was successfully characterized by spectroscopy [IR and NMR (¹H and ¹³C)] and mass spectrometry. The chemosensing study performed in acetonitrile/water (4:1) solvent media, via UV-vis and fluorescence spectroscopy, established its selective sensitivity for Pb(II) and Hg(II) species among the list of explored metal ions with the limits of detection being 8.6 and 11 μM, respectively. Additionally, the ¹H NMR and IR spectra of the synthesized TCT-metal complex also confirmed the metal-ligand binding. Besides, the effect of time and temperature on the binding ability of TCT with Pb(II) and Hg(II) was also studied via UV-vis spectroscopy. Furthermore, density functional theory studies put forward the structural comprehension of the sensor by availing the hybrid density functional (B3LYP)/6311G++(d,p) basis set of theory which was subsequently utilized for investigating its anti-inflammatory potential by performing docking analysis with human leukotriene b4 protein.

Remediation of noxious wastewater using nanohybrid adsorbent for preventing water pollution

Removal of toxic elements from wastewater effluent has got a lot of attention because of their severe negative effects on human and environmental health. In the past few years, rapid urbanization and industrial activities in developing countries have exacerbated the destruction of the environment. Most of the wastewater effluents are discharged untreated or inadequately treated, which has become a major concern due to its impact on sustainability and the environment. This is imperative to implement, innovative and resourceful wastewater treatment technologies requiring low investment. Among the various treatment technologies, cutting-edge processes in nano-material sciences have recently piqued the interest of scientists. Nanohybrid absorbents have the potential in improving wastewater treatment and increase water supply by utilizing unconventional water resources. Carbon nanotubes, titanium oxide, manganese oxide, activated carbon (AC), magnesium oxide, graphene, ferric oxides, and zinc oxide are examples of nano-adsorbents that are used to eliminate pollutants. This also demonstrated the effective removal of contaminants along with the harmful effects of chemicals, colorants, and metals found in wastewater. The present manuscript examines potential advances in nanotechnology in wastewater treatment for the prevention of water and soil pollution. This systematic review aims to highlight the importance of nanohybrid absorbents treatment technology for wastewater treatment and to explain how nanohybrid absorbents have the potential to revolutionize industrial pollution. There are also other published review articles on this topic but the present review covers an in-depth information on nano-adsorbents and their targeted contaminants.

Source apportionment of bioavailable trace metals in soil based on chemical fractionation and its environmental implications

The bioavailable trace metals are closely related to environmental safety and human health, which might have different source characteristics from the total trace metals in soil. To identify such differences, 31 farmland soil samples were collected from a typical agricultural watershed in East China and analyzed for bioavailable trace metal sources by using chemical fractionation, linear regression, and receptor model. Results showed that the total concentrations of Pb, Cu, Zn, Cr, and Ni in the soils were 1.25-1.59 times higher than watershed background values, but they were all dominated by the residual fraction (63.39-86.36%) according to a modified Community Bureau of Reference (BCR) sequential extraction procedure. Both chemical fractionation and enrichment factors (EFs) indicated a major contribution of the natural source to the total trace metal concentrations in the soils. However, linear regressions revealed that 60.07-89.88% of the bioavailable Pb, Cu, Zn, and Ni concentrations were contributed by anthropogenic sources. Atmospheric deposition and livestock manure were identified as the two major anthropogenic sources, and their contributions were further estimated by using a multiple linear regression of absolute principal component scores (MLR-APCS) model. Together with natural contribution, atmospheric deposition could contribute 74.55-89.86% of bioavailable Pb, Cr, and Ni concentrations. Livestock manure contributed 85.54% of bioavailable Cu and 80.05% of bioavailable Zn concentrations, respectively. These results implied that the bioavailable trace metals were influenced by both anthropogenic and natural sources, but more influenced by anthropogenic sources for bioavailable Pb, Cu, Zn, and Ni in the soils. Special attention should be paid to bioavailable Pb when implementing effective pollution control strategies in this watershed. Moreover, the risk caused by bioavailable trace metal losses from soils to aquatic system should not be ignored.

Issues and Challenges in the Application of the IEUBK Model in the Health Risk Assessment of Lead: A Case Study from Blantyre Malawi

The risk assessment of lead (Pb) requires the use of biokinetic models to translate measured concentrations of Pb in food and environmental media into blood lead (BPb). The aim of this study was to assess the applicability of the Integrated Exposure Uptake Biokinetic (IEUBK) model in the health risk assessment of Pb among children in Blantyre. Children (152) aged 1–6 years were recruited into this cross-sectional study, and foods, house dust, playground soil, water, and venous blood (1 mL) were collected and analyzed for Pb. A seven-day food frequency questionnaire (FFQ) was used to collect food consumption data. The concentrations of Pb ranged from 0.01 to 3.3 mg/kg in food, 2.3 to 265 mg/kg and 1.5 to 482 mg/kg in house dust and playground soil, respectively, as well as 2.0 µg/dL to 50.4 µg/dL and 6.8 to 39.2 µg/dL for measured and predicted BPb, respectively. Various statistical tests indicated less than satisfactory agreement between measured and predicted BPb values. Despite the lack of reliable food consumption data and other limitations, both the predicted and measured BPb values indicate that children in Blantyre are exposed to high levels of Pb, largely through food and soil as a minor source.

Clinical biochemical parameters associated with the exposure to multiple environmental metals in residents from Kabwe, Zambia

Lead (Pb) interferes with various bodily functions. Although high blood Pb (Pb-B) levels in residents from Kabwe, Zambia have been reported, the accumulation pattern of other metals remains unknown. The study was designed to determine the Pb-B, blood cadmium (Cd-B), and zinc (Zn-B) values of 504 representative samples from Kabwe, as well as the potential associated adverse health effects. The Pb-B level ranged from 0.79 to 154.75 μg/dL and generally increased in areas near the mine. A significant elevation of Cd-B was observed in two areas (0.37 ± 0.26 and 0.32 ± 0.30 μg/L) where the two highest mean Pb-B levels were recorded. By contrast, the Zn-B values did not differ greatly with respect to area. Some blood biochemical parameters relating to hepatic and renal functions were out of the normal range in approximately 20-50% of studied adult participants. The δ-aminolevulinic acid dehydratase (δ-ALAD) activity was significantly inhibited in the two areas contaminated by Pb and Cd. A significant negative relationship was observed between metal levels and clinical parameters, e.g., between Pb-B and δ-ALAD for all the age categories and between Cd-B and the estimated glomerular filtration rate for all the age categories except 0-4 years. The elevated Cd-B in areas near the mine relative to the other areas suggested the potential adverse health effects of Cd and/or the interaction of Pb and Cd. A significant association of metal levels with clinical parameters also indicated the effects of metal exposure on hematopoietic, hepatic, and renal systems.

Excessive dietary lead reduces growth performance and increases lead accumulation in pigs

Objective: The objective of this study was to investigate the influence of dietary lead (Pb) supplementation and feeding period on growth performance, organ weight, and Pb accumulation in pigs.Methods: In a 56-day feeding experiment, a total of 48 barrows with initial body weight 10.4±0.6 kg were allotted to 2 dietary treatments (0 and 200 mg/kg of supplemental Pb) in a completely randomized design with 6 replicates. Body weight and feed intake were recorded to calculate growth performance. At the end of each 14 day-period (on days 14, 28, 42, and 56), an animal was randomly selected from each pen and slaughtered to collect blood samples, hair samples, left 5th rib, heart, liver, kidneys, lungs, and longissimus dorsi muscle samples.Results: Average daily gain and average daily feed intake were reduced (p<0.05) by supplemental Pb during the day 42 to 56. Relative kidney weight to body weight was linearly increased with increasing feeding period in pigs fed the Pb-supplemented diet, but not in pigs fed the control diet (p<0.05). The Pb concentrations in hair, left 5th rib, kidneys, and lungs were linearly increased with longer feeding period in pigs fed the Pb-supplemented diet, but not in pigs fed the control diet (p<0.01).Conclusion: Dietary Pb supplementation caused growth retardation and Pb accumulation in most organs, particularly in hair, bone, and kidneys in a time-dependent manner.

Effects of varying dietary intoxication with lead on the performance and ovaries of laying hens

In this study, we explored the effect of dietary lead nitrate on zootechnical performance, egg quality, accumulation of ovarian plumbum (Pb), follicular atresia rate, and ovarian oxidative stress in laying hens. Furthermore, the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling molecule was studied to reveal the molecular mechanism of the stress. A total of 512 Hy-Line Brown laying hens aged 40 wk were randomly allocated to 4 groups (with 8 pens per group and 16 hens per pen). The Pb concentrations used to treat the 4 groups were 3.20, 33.20, 63.20, and 93.20 mg/kg. The results revealed that dietary Pb exposure significantly linearly reduced the zootechnical performance (P < 0.01) but significantly linearly increased the feed conversion ratio (P < 0.01). The dietary Pb exposure significantly linearly reduced the Haugh units (P < 0.01), albumen height (P < 0.01), eggshell thickness (P < 0.01), and eggshell strength (P < 0.01). In addition, the dietary Pb exposure significantly enhanced the follicular atresia rate (P < 0.01). After dietary Pb exposure, superoxide dismutase (P < 0.01) and glutathione peroxidase (GSH-Px) (P < 0.01) activities and glutathione (P < 0.01) contents were significant decreased quadratically, and there were significant linear decreases in the activities of catalase (CAT) (P < 0.01) and glutathione reductase (GR) (P < 0.01), whereas malondialdehyde content was significantly linearly increased (P < 0.01). In addition, except for manganese superoxide dismutase, the gene expressions of copper-zinc superoxide dismutase (P < 0.01), CAT (P < 0.01), and GR (P < 0.01) were significant decreased linearly. In addition, there were significantly quadratic decreases in the mRNA expressions of GSH-Px (P < 0.01) and Nrf2 (P < 0.01). By way of contrast, the Kelch-like ECH-associated protein 1 (Keap1) gene expression was significantly linearly increased (P < 0.01). In conclusion, dietary Pb exposure could induce oxidative stress by impairing the Nrf2-Keap1 signal pathway in the ovaries of laying hens.

Changes of Atmospheric and Blood Concentrations of Lead and Cadmium in the General Population of South Korea from 2008 to 2017

We measured changes in atmospheric and blood levels of lead and cadmium in the South Korean general population during the past decade. Blood data of 16,873 adults were taken from the Korean National Health and Nutrition Examination Survey (KNHANES, 2008-2017). Atmospheric data were taken from 66 air quality monitoring sites in 16 different regions in South Korea. From 2008 to 2017, the geometric mean (GM) blood lead level decreased from 2.37 to 1.46 μg/dL (38.4% decrease), and the atmospheric lead concentration decreased by 61.0% in the overall population. During this time, the GM blood cadmium level decreased from 0.88 to 0.72 μg/L (18.2% decrease), and the atmospheric cadmium concentration decreased by 63.6%. Multiple linear regression analysis indicated that a half reduction in air lead was associated with a 0.09 μg/dL decrease in blood lead (95% CI: 0.03 to 0.15) in a subgroup of the metropolitan city population. However, a half reduction in air cadmium had no significant effect on blood cadmium. Multiple linear regression analyses indicated that the decrease in blood lead level over 10 years in Korea was related to the decrease in atmospheric lead concentration. However, the decrease in blood cadmium level during this time was not significantly associated with the decrease in atmospheric cadmium concentration. Our findings suggest that inhalation is a major source of lead exposure, but not of cadmium exposure. Ingestion of dietary cadmium presumably has a stronger impact on blood cadmium levels.

Selenium nanoparticles prevents lead acetate-induced hypothyroidism and oxidative damage of thyroid tissues in male rats through modulation of selenoenzymes and suppression of miR-224

Selenium nanoparticles (Se-NPs) are customizable drug delivery vehicles that show good bioavailability, higher efficacy and lower toxicity than ordinary Se. Pre-treatment of male rats with these NPs has been recently shown to exert a protective effect against chromium-induced thyroid dysfunction. This study, therefore, aimed to investigate and characterize the potential protective mechanism of Se-NPs against lead (Pb) acetate-induced thyrotoxicity. We found that prophylactic and concurrent treatment of Pb acetate-exposed rats with Nano-Se (0.5 mg/kg, i.p) for 15 wk significantly alleviated the decrease in free triiodothyronine (fT3) and free thyroxine (fT4) levels as well as fT3/fT4 ratio% and the increase in thyroid stimulating hormone (TSH) levels to approach control values. This was accompanied by a reduction in the accumulation of Pb in serum and thyroid tissues as well as maintenance of thyroidal pro-oxidant/antioxidant balance and iodothyronine deiodinase type 1 (ID1), an essential enzyme for metabolizing of T4 into active T3, gene expression. Surprisingly, miR-224, a direct complementary target of ID1 mRNA, expression in the thyroid tissues was significantly down-regulated in Nano-Se-pre- and co-treated Pb acetate intoxicated animals. Such changes in miR-224 expression were negatively correlated with the changes in ID1 gene expression and serum fT3 level. These results suggest that Se-NPs can rescue from Pb-induced impairment of thyroid function through the maintenance of selenoproteins and down-regulation of miR-224.

Role of caftaric acid in lead-associated nephrotoxicity in rats via antidiuretic, antioxidant and anti-apoptotic activities

Background Lead is a toxic metal that is widely distributed in the environment where caftaric acid (CA) is the ester form of caffeic acid where CA is the major dietary polyphenol present in various foods and beverages. The aim of this study was to evaluate the effect of CA in lead acetate (LA)-associated nephrotoxicity through antidiuretic, antioxidant and anti-apoptotic activities. Methods Forty-eight male albino rats divided into six equal groups; group 1 control injected intraperitoneally (ip) with saline (1 mL/kg of bw) over two weeks period, group 2 injected ip with CA (80 mg/kg of bw) over two weeks period, groups 3, 4, 5 and 6 injected ip with 100 μmol/kg of bw LA over two weeks period where groups 4, 5 & 6 co-injected ip with 1-deamino-8-D-arginine vasopressin (dDAVP) drug (1 mg/kg of bw), CA (40 mg/kg of bw), and CA (80 mg/kg of bw), respectively. Results The results obtained revealed that LA induced a significant decrease in kidney weight and serum sodium, potassium and chloride, but caused a significant increase in urinary volume, urinary excretion of sodium, potassium and chloride, serum urea, creatinine and uric acid. The LA also caused a significant decrease in kidney superoxide dismutase, glutathione peroxidase and induced a significant decrease in glutathione level while caused an increase in lipid peroxidation level. In addition, LA caused a decrease in p53 expression while induced an increase in bcl-2 expression in the kidney tissues. Co-injection of CA to LA-treated group restored all the above parameters to approach the normal values. The results supported with histopathological examinations. Conclusions In conclusion, the effect of CA on LA-related nephrotoxicity was occurred through antidiuretic, antioxidant, anti-apoptotic activities where the effect of CA was dose dependent.

Environmental exposures to lead, mercury, and cadmium among South Korean teenagers (KNHANES 2010-2013): Body burden and risk factors

INTRODUCTION

Limited information is available on the association of age and sex with blood concentrations of heavy metals in teenagers. In addition, factors such as a shared family environment may have an association. We analyzed data from the Korean National Health and Nutrition Examination Survey (KNHANES, 2010-2013) to determine whether blood levels of heavy metals differ by risk factors such as age, sex, and shared family environment in a representative sample of teenagers.

METHODS

This study used data obtained in the KNHANES 2010-2013, which had a rolling sampling design that involved a complex, stratified, multistage, probability-cluster survey of a representative sample of the non-institutionalized civilian population in South Korea. Our cross-sectional analysis was restricted to teenagers and their parents who completed the health examination survey, and for whom blood measurements of cadmium, lead, and mercury were available. The final analytical sample consisted of 1585 teenagers, and 376 fathers and 399 mothers who provided measurements of blood heavy metal concentrations.

RESULTS

Male teenagers had greater blood levels of lead and mercury, but sex had no association with blood cadmium level. There were age-related increases in blood cadmium, but blood lead decreased with age, and age had little association with blood mercury. The concentrations of cadmium and mercury declined from 2010 to 2013. The blood concentrations of lead, cadmium, and mercury in teenagers were positively associated with the levels in their parents after adjustment for covariates.

CONCLUSION

Our results show that blood heavy metal concentrations differ by risk factors such as age, sex, and shared family environment in teenagers.

Multi-Omics Reveals that Lead Exposure Disturbs Gut Microbiome Development, Key Metabolites, and Metabolic Pathways

Lead exposure remains a global public health issue, and the recent Flint water crisis has renewed public concern about lead toxicity. The toxicity of lead has been well established in a variety of systems and organs. The gut microbiome has been shown to be highly involved in many critical physiological processes, including food digestion, immune system development, and metabolic homeostasis. However, despite the key role of the gut microbiome in human health, the functional impact of lead exposure on the gut microbiome has not been studied. The aim of this study is to define gut microbiome toxicity induced by lead exposure in C57BL/6 mice using multiomics approaches, including 16S rRNA sequencing, whole genome metagenomics sequencing, and gas chromatography-mass spectrometry (GC-MS) metabolomics. 16S rRNA sequencing revealed that lead exposure altered the gut microbiome trajectory and phylogenetic diversity. Metagenomics sequencing and metabolomics profiling showed that numerous metabolic pathways, including vitamin E, bile acids, nitrogen metabolism, energy metabolism, oxidative stress, and the defense/detoxification mechanism, were significantly disturbed by lead exposure. These perturbed molecules and pathways may have important implications for lead toxicity in the host. Taken together, these results demonstrated that lead exposure not only altered the gut microbiome community structures/diversity but also greatly affected metabolic functions, leading to gut microbiome toxicity.

Evaluation of blood lead level in methamphetamine users in Tehran

BACKGROUND

Given the increasing number of lead poisoning in opioids users and since no study has been conducted so far to review lead poisoning in methamphetamine (crystal) users, this study aimed to investigate blood lead level in methamphetamine addicts.

METHODS

This study was conducted on 20 patients with methamphetamine poisoning and their blood lead level was measured. The subjects were selected from among patients with a history of continuous use of methamphetamine, without a history of using opiates in the past 6 months confirmed by a negative urine tests, and without a history of heavy metal poisoning.

RESULTS

Of all, 18 patients were male and the mean age was 32 ± 10 years; 17 patients were abusing the drug via inhalation and three persons via oral administration. The mean blood lead level was 2.3 ± 1.1 μg/dL and poisoning was not observed in any of the cases. Blood lead level was not associated with age, sex, dosage, and route of administration.

CONCLUSION

Although blood lead level was not at poisoning level in people who only used methamphetamine in Iran, due to the simultaneous use of other substances and because of non-specific symptoms, lead poisoning must be suspected in all cases of substances poisoning.

Effect of LA on the Growth and Development of the Main Organs in Female Mice

Effects of lead acetate (LA) on the growth and development of major organs in female mice were studied. Female mice were divided randomly into four treatment groups and one control group. In treatment groups, mice were injected with different concentrations of LA solution every 2 days; whereas control-group mice received equal volumes of sterile normal saline. Body weight (BW) and symptoms were recorded every 2 days. After LA exposure, mice were executed by cervical dislocation and main organs (heart, liver, spleen, lung, kidney) collected for evaluation of morphologic and histologic changes. LA could greatly affect increases in BW, and BW decreased with increasing dose and time of exposure to LA. Compared with the control group, organ coefficients in treatment groups were of the order kidney and spleen > liver and lung > heart and demonstrated obvious dose-time effects. LA exposure could damage the heart, liver, spleen, lung, and kidney. Damage to the kidney and spleen was the most severe, followed by that to the liver, heart, and lung. Damage was aggravated with increasing doses and exposure time to LA in an obvious dose-time relationship; when LA dose was ≥20 mg/kg, the growth and development of mice were obviously inhibited. These results suggest that long-term exposure to low-dose LA can result in universal pathologic damage to mouse organs and that severity is dependent on the dose and duration of LA exposure.

[Drinking water quality and safety]

The purpose of drinking water legislation is to guarantee the quality and safety of water intended for human consumption. In the European Union, Directive 98/83/EC updated the essential and binding quality criteria and standards, incorporated into Spanish national legislation by Royal Decree 140/2003. This article reviews the main characteristics of the aforementioned drinking water legislation and its impact on the improvement of water quality against empirical data from Catalonia. Analytical data reported in the Spanish national information system (SINAC) indicate that water quality in Catalonia has improved in recent years (from 88% of analytical reports in 2004 finding drinking water to be suitable for human consumption, compared to 95% in 2014). The improvement is fundamentally attributed to parameters concerning the organoleptic characteristics of water and parameters related to the monitoring of the drinking water treatment process. Two management experiences concerning compliance with quality standards for trihalomethanes and lead in Barcelona's water supply are also discussed. Finally, this paper presents some challenges that, in the opinion of the authors, still need to be incorporated into drinking water legislation. It is necessary to update Annex I of Directive 98/83/EC to integrate current scientific knowledge, as well as to improve consumer access to water quality data. Furthermore, a need to define common criteria for some non-resolved topics, such as products and materials in contact with drinking water and domestic conditioning equipment, has also been identified.

Behavioral effects induced by subchronic exposure to Pb and their reversion are concentration and gender dependent

Lead (Pb) seems to be involved in the etiology of psychological pathologies. This study investigated the effects of subchronic Pb exposure from weaning to adulthood on anxiety, depression and aggressiveness in male and female Swiss mice. Moreover, the reversibility of the effects was evaluated retesting the animals 30 days after the end of exposure. Swiss male and female mice (21 days) were exposed to 0, 50, 100 or 500 ppm of Pb, as Pb acetate, in drinking water for 70 days and were submitted to the forced swimming, tail suspension, elevated plus-maze or intruder—resident tests. Pb exposure to 50 and 500 ppm induced anti-depressant-like effect in both males and females, whereas exposure to 500 ppm induced anxiogenic effect only in males. Interruption of exposure was able to reverse the behavioral alterations in females, but not in males exposed to the highest concentration (500 ppm). Our results suggest that behavioral effects induced by subchronic exposure to Pb from weaning to adulthood and their reversion are concentration and gender dependent. [Human & Experimental Toxicology] (2007) 26, 733—739

Histochemical Characterization of Renal Phosphatases in Rats Treated With Lead

Seven groups of 84 male white rats ( Rattus norvegicus) were exposed to lead acetate (0, 0.125, 0.25, 0.5, 1.0, 2.0, and 4% for 1 to 5 months) in drinking water to investigate possible histochemical changes in the activity of renal phosphatases due to lead intoxication. In comparison with respective control rats, chronic exposure to subtoxic doses of lead increased the activities of acid-, neutral-, alkaline-, and membrane-bound Na+-K+ adenosine triphosphatase and glucose-6-phosphatase. In contrast, significant reduction in the activities of 5-nucleotidase and mitochondrial adenosine triphosphatase was observed. Changes in the activity of renal phosphatases were seen mainly in the epithelium of the proximal tubules and, to a lesser extent, in the medullary interstitial cells and the glomeruli as well. These histochemical findings led us to conclude that such changes in the activity of phosphatases were due to long-term exposure to subtoxic doses and could be an adaptation to the metabolic, structural, and functional alterations in the organelles of the renal cells due to lead intoxication.

Effects of Naringenin on Oxidative Stress and Histopathological Changes in the Liver of Lead Acetate Administered Rats

Lead has several adverse effects on the body due to one of the environmental pollutants. We aimed to determine the effects of naringenin on the oxidative stress and the hepatic damage against lead acetate treatment in the liver of male rats. Naringenin was administered by orogastric gavage (50 mg/kg) and lead acetate was given as daily 500 parts per million in drinking water for 4 weeks. Lead and antioxidant activities were measured, and histopathological evaluation was performed in the liver. Lead concentrations, malondialdehyde, and antioxidant activity were restored by the naringenin. The grade of necrosis, hydropic degeneration, and hepatic cord disorganization was decreased by the naringenin. However, there were no differences in the degree of sinusoidal congestion, hepatic steatosis, and capsular fibrosis between lead acetate and naringenin + lead acetate groups. We can suggest that naringenin has antioxidant and chelating effects in the liver. Nevertheless, this effect is not enough against the lead acetate induced hepatic injury.

Reliability of stable Pb isotopes to identify Pb sources and verifying biological fractionation of Pb isotopes in goats and chickens

Stable Pb isotope ratios (Pb-IRs) have been recognized as an efficient tool for identifying sources. This study carried out at Kabwe mining area, Zambia, to elucidate the presence or absence of Pb isotope fractionation in goat and chicken, to evaluate the reliability of identifying Pb pollution sources via analysis of Pb-IRs, and to assess whether a threshold for blood Pb levels (Pb-B) for biological fractionation was present. The variation of Pb-IRs in goat decreased with an increase in Pb-B and were fixed at certain values close to those of the dominant source of Pb exposure at Pb-B > 5 μg/dL. However, chickens did not show a clear relationship for Pb-IRs against Pb-B, or a fractionation threshold. Given these, the biological fractionation of Pb isotopes should not occur in chickens but in goats, and the threshold for triggering biological fractionation is at around 5 μg/dL of Pb-B in goats.

Effects of paternal cadmium exposure on the sperm quality of male rats and the neurobehavioral system of their offspring

Cadmium (Cd) is a testicular toxicant and an endocrine disruptor in humans and rodents. The aim of the present study was to investigate the effects of paternal Cd exposure on the sperm quality of male rats and the neurobehavioral system of their offspring. A total of 12 male rats were randomized into a control and Cd-treated group (n=6 per group), and 12 female rats were administered distilled water and randomly divided into two groups (n=6 per group). Subsequently, sperm motility, viability, malformation rate of male rats and the neuromotor maturation, antioxidant ability, Cd accumulation in different organs of their offspring were measured. Compared with the control rats, the sperm motility rate and vitality were significantly reduced (P<0.01) and the sperm malformation rate was significantly increased (P<0.01) in the male rats following Cd treatment. Regarding the nervous system development of the offspring, the cliff-avoidance reflex, surface-righting reflex and negative geotaxis results exhibited significant differences between the Cd exposure and control groups (P<0.05). The Cd content in the liver and heart of the offspring of the Cd exposure rats was higher than that in the control rats (P<0.05), and the liver content peaked on postnatal day 21. Furthermore, Cd exposure affected the antioxidant activity of the offspring, which was shown by glutathione, malondialdehyde and superoxide dismutase assays. Collectively, the results indicate that Cd exposure affects the sperm quality of male rats and the neurobehavioral system of their offspring.

Lead, Arsenic, and Manganese Metal Mixture Exposures: Focus on Biomarkers of Effect

The increasing exposure of human populations to excessive levels of metals continues to represent a matter of public health concern. Several biomarkers have been studied and proposed for the detection of adverse health effects induced by lead (Pb), arsenic (As), and manganese (Mn); however, these studies have relied on exposures to each single metal, which fails to replicate real-life exposure scenarios. These three metals are commonly detected in different environmental, occupational, and food contexts and they share common neurotoxic effects, which are progressive and once clinically apparent may be irreversible. Thus, chronic exposure to low levels of a mixture of these metals may represent an additive risk of toxicity. Building upon their shared mechanisms of toxicity, such as oxidative stress, interference with neurotransmitters, and effects on the hematopoietic system, we address putative biomarkers, which may assist in assessing the onset of neurological diseases associated with exposure to this metal mixture.

Determination of some soft drink constituents and contamination by some heavy metals in Nigeria

Soft drinks are consumed daily in Nigeria due to its affordability, characteristic taste, and thirst quenching potential. However, the high demand may compromise the quality of production with possible contamination of heavy metals which have shown to cause intoxication and death in humans. This study evaluated some constituents of twenty-six soft drinks in Nigeria and investigated the presence of some heavy metal contaminants. The soft drinks were screened for the presence of sugar, carbon dioxide, phosphate and alcohol as well as the pH and acidity determined. The level of cadmium, mercury and lead were determined using atomic absorption spectrophotometer. The study showed the presence of sugar, carbon dioxide, phosphate, and alcohol in the soft drinks. The soft drinks were acidic in nature, pH ranging from 3 to 5 with a mean of 3.6 and the acid concentration was relatively low between 3 and 12 g/L with a mean of 8.1 g/L. Lead was present in all the samples ranging from 0.17 to 3.39 mg/L with a mean of 0.8, mercury was present in 22 samples ranging from 0.29 to 11.32 mg/L with a mean of 2.08 mg/L while cadmium was present only in one sample (0.149 mg/L). When compared to EPA, WHO and NIS standards, the levels of the heavy metal contaminants were above the tolerated limits for good quality drinking water in most samples. These results suggest that soft drinks in Nigeria may be contaminated with heavy metals which constitute a major public health problem. Thus, quality control is recommended during the production process especially at the stages of sterilization and purification.

Lead poisoning in children from townships in the vicinity of a lead-zinc mine in Kabwe, Zambia

Childhood lead poisoning is a serious public health concern worldwide. Blood lead levels exceeding 5 μg dL(-1) are considered elevated. In Kabwe, the capital of Zambia's Central Province, extensive Pb contamination of township soils in the vicinity of a Pb-Zn mine and posing serious health risk to children has been reported. We investigated BLLs in children under the age of 7 years in townships around the mine; where blood samples were collected and analyzed using an ICP-MS. All of the sampled children had BLLs exceeding 5 μg dL(-1). Children in these areas could be at serious risk of Pb toxicity as 18% of the sampled children in Chowa, 57% (Kasanda) and 25% (Makululu) had BLLs exceeding 65 μg dL(-1). Eight children had BLLs exceeding 150 μg dL(-1) with the maximum being 427.8 μg dL(-1). We recommend that medical intervention be commenced in the children with BLL exceeding 45 μg dL(-1).

Evidence that cognitive deficit in children is associated not only with iron deficiency, but also with blood lead concentration: a preliminary study

OBJECTIVE

To investigate whether blood lead concentrations are elevated in iron-deficient children, and to examine the association between iron deficiency and/or elevated blood lead concentration and cognitive deficits in children.

METHOD

The present study is a component of the Mothers' and Children's Environmental Health (MOCEH) study, a multi-center birth cohort project in Korea that began in 2006. The study cohort consisted of 194 children who underwent testing of blood lead and serum C-reactive proteins (CRPs) and ferritin concentrations, and the Korean version of the Wechsler Preschool and Primary Scale of Intelligence, revised edition (WPPSI-R), at 60 months of age. In addition, the mothers' blood lead concentrations during pregnancy were included in the analyses. Multivariate linear regression analysis was performed to analyze the correlation between high blood lead and low serum ferritin concentrations, after adjustment for covariates, in children, as well as to analyze the association of verbal IQ with serum ferritin and blood lead concentrations.

RESULTS

Lead and ferritin concentrations were inversely and significantly associated in children after adjustment for covariates. Moreover, both concentrations were associated with verbal IQ, after adjustment for covariates, and each was associated with cognitive deficits after adjustment for the other. Sobel test statistics showed that blood lead concentration was a significant partial mediator for the relationship between iron deficiency and verbal IQ.

CONCLUSION

Due to the results discussed in the present study, cognitive deficit in children seems to be associated not only with iron deficiency, but also with blood lead concentration.

Geochemical variability of heavy metals in soil after land use conversions in Northeast China and its environmental applications

The long-term agricultural reclamation since the 1950s has resulted in significant land use change from natural landscape to cultivated land in the Sanjiang Plain of Northeast China, which has had important consequences for many soil physical, chemical and biological processes. To understand the impact of land use conversions on heavy metal geochemistry, soil samples were collected from natural wetland, natural forestland, paddy land and dry farmland in a case study area and analyzed for total concentrations and chemical fractions of six heavy metals. Results showed that the natural wetland reclamation for the paddy land has caused obvious losses of Cd, Cu and Zn from the soils. In addition, a significant decrease in the Zn concentration was found after the land conversion from natural forestland to dry farmland. Because all the analyzed heavy metals predominated in the stable residual fraction regardless of the land use type, the response of metal mobility to the land use conversions was generally weak. Consequently, soil erosion was identified as the major factor that enhances heavy metal losses in the cultivated lands, especially in the paddy land. The close link between heavy metal loss and the reduction of clay and organic matter contents after land reclamation suggested that the diffuse heavy metal pollution occurred mainly in small erosion events. Considering the continuous paddy land expansion, special attention should be paid to the bioaccumulation of Pb in the paddy rice. Overall, these findings can help to improve the sustainability and safety of intensive agricultural activities in Northeast China as well as other similar areas.

Iron deficiency increases blood lead levels in boys and pre-menarche girls surveyed in KNHANES 2010-2011

INTRODUCTION

We present data from the Korean National Health and Nutritional Examination Survey (KNHANES) 2010-11 on the distribution of blood lead levels, and examine their association with iron deficiency in a representative sample of the adolescent Korean population.

METHODS

This study was based on data obtained from KNHANES, in which a rolling sampling design was used to perform a complex, stratified, multistage probability cluster survey of a representative sample of the non-institutionalized civilian population in South Korea. Serum ferritin was categorized into three levels: low (serum ferritin <15.0μg/L), low normal (serum ferritin 15.0-30.0μg/L for girls and 15.0-50.0 for boys), and normal (serum ferritin ≥30.0μg/L for girls and ≥50.0 for boys), and its association with blood lead levels was assessed after adjustment for various demographic and lifestyle factors.

RESULTS

The geometric mean (GM) of blood lead in the low serum ferritin group was significantly higher than that in the normal group among boys but not girls. After controlling for covariates, multiple regression analysis showed that blood lead was inversely correlated with serum ferritin levels in boys and pre-menarche girls only.

DISCUSSION

The present study shows that iron deficiency increases blood lead levels in a representative sample of the male and pre-menarche female adolescent population, as evaluated in KNHANES. The confounding effect of estrogen on blood lead levels should be considered.

Antioxidative effects of hesperetin against lead acetate-induced oxidative stress in rats

Objectives:

Oxidative stress with subsequent lipid peroxidation (LP) has been suggested as a mechanism for lead-induced toxicity. The current study was carried out to evaluate antioxidant activity of hesperetin against lead acetate-induced oxidative stress.

Materials and Methods:

The male rats were treated with hesperetin in combination with lead acetate (500 mg/L).

Results:

The results indicated that hesperetin alone did not induce any significant changes in the biochemistry of serum, liver, and kidney tissues. On the other hand, lead-induced oxidative stress as indicated by significant changes in serum biochemical parameters, including increased lipid peroxide and decreased reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) levels in liver and kidney tissues. Hesperetin succeeded in improving these biochemical parameters towards the normal values of control.

Conclusions:

It suggests that hesperetin shows antioxidant activity and plays a protective role against lead-induced oxidative damage in liver and kidney of rats.

Effects of iron therapy on blood lead concentrations in infants

To determine whether blood lead concentration is elevated in iron-deficient infants, blood lead and serum ferritin concentrations, serum iron/transferring iron-binding capacity (Fe/TIBC) and complete blood counts were measured in 30 iron deficient and 35 control infants, aged 6-24 months. All 30 iron-deficient infants received iron supplementation (ferric hydroxide-polymaltose complex, 6mg/kg Fe(3+)/day) for 1-6 months. Blood lead concentrations were measured in 18 of the iron deficient infants after their ferritin levels returned to the normal range. The geometric mean blood lead concentration was higher in iron deficient than in control infants (1.846 vs. 1.416μg/dL). After iron therapy, the blood lead levels of iron-deficient infants decreased significantly compared with pre-treatment levels (1.785 vs. 2.386μg/dL), and the hemoglobin and ferritin concentrations increased significantly. These findings indicate that iron deficiency increases blood lead concentrations in infants with very low blood lead concentrations.

Dietary nutrient and food intake and their relations with serum heavy metals in osteopenic and osteoporotic patients

Several studies have reported that heavy metals have a relation with osteoporosis and osteoporotic fractures. In this study, we investigated the association between heavy metal exposure status, as assessed by serum major heavy metals such as lead (Pb), cadmium (Cd), and mercury (Hg) and bone mineral density (BMD) status among Korean adults. A total of 64 adults participated in this study and were assigned to one of three study groups based on the T-score of spine BMD: a normal group (n = 21, T-score > -1), osteopenia group (n = 29, -2.5 < T-score ≤ -1) and osteoporosis group (n = 14, T-score ≤ -2.5). We also assessed serum levels of heavy metals (Pb, Cd and Hg) by using atomic absorption spectrometer (AAS) and daily nutrient and food intakes for 3 days by using 24-hr recall method in the subjects. The mean age was significantly higher in the osteoporosis group compared with the osteopenia and normal groups (p < 0.001). There was no significant difference in serum levels of Pb, Cd and Hg among the three groups after adjusting for age. Daily intakes of energy, nutrients were not significantly different among the three groups. The osteoporosis group consumed significantly higher fish and shellfish than the other groups (p < 0.05). In the correlation analysis controlling for age, sex, BMI, and BMD status, the serum Cd level was significantly negatively correlated with intake of cereals, milks and total food. In summary, we did not find a direct association between serum heavy metal levels and BMD status. However, negative relationships were found between serum heavy metal levels and intake of some foods.

An invasive DNA approach toward a general method for portable quantification of metal ions using a personal glucose meter

We report herein a general methodology for metal ion detection using low-cost, simple, and widely accessible personal glucose meters through an invasive DNA approach.

Prenatal and lactational lead exposure enhanced oxidative stress and altered apoptosis status in offspring rats' hippocampus

Oxidative stress and apoptosis facilitation in the developing central nervous system (CNS) have been inferred as two mechanisms related to lead's neurotoxicity, and excessive reactive oxygen species (ROS) can promote oxidative stress and apoptosis facilitation. Few studies systematically investigated the potential relationship among oxidative stress, ROS generation, and apoptosis facilitation after lead exposure in earlier life as a whole. To better understand the adverse effect on the developing central nervous system (CNS) after lead exposure during pregnancy and lactation, the indexes of oxidative stress, apoptosis status, and Bax and Bcl-2 expression of offspring rats' hippocampus were determined. Pregnant rats were randomly divided into four groups and given free access to drinking water which contained 0 %, 0.05 %, 0.1 %, and 0.2 % Pb(AC)(2) respectively from gestation day 0 to postnatal day 21 (PND21). Results showed that ROS and malondialdehyde level of either PND7 or PND21 pups' hippocampus were significantly raised; reduced glutathione level and superoxide dismutase activity were obviously decreased following the increase of blood and brain lead level. Similar to apoptotic indexes, Bax/Bcl-2 ratio increased after 0.1 % and 0.2 % Pb(AC)(2) exposure, especially for the pups on PND7. Comparing with cortex, the hippocampus seemed much more sensitive to damage induced by lead. We concluded that the disruption of pro-oxidant and antioxidant balance and apoptosis facilitation could be associated with the mechanisms of neurotoxicity after lead exposure in earlier life.

Metal distribution in tissues of free-range chickens near a lead-zinc mine in Kabwe, Zambia

Concentrations of Pb, Cd, and other metals in tissues of 17 free-range and 32 commercial broiler chickens from the Kabwe mining town in Zambia were determined. Mean concentrations of Pb and Cd exceeded maximum levels for human consumption in some organs including muscle (Pb only) in free-range chickens, in contrast to low levels in broiler chickens. Human consumers in Kabwe could be exposed to Pb and Cd in free-range chickens.

Antimony, arsenic and lead distribution in soils and plants of an agricultural area impacted by former mining activities

An agricultural area impacted by the former exploitation of an arsenical lead-antimony deposit was studied in order to assess the current and eventual environmental and health impacts. Samples of soils and cultivated (wheat) and spontaneously growing plants were collected at different distances from the mine pits and analyzed for the toxic element content and distribution. The soil total concentrations of Sb, As and Pb found in the uppermost soil layer (14.1-324, 246-758 and 757-10,660 mg kg(-1), respectively) greatly surpass their maximum tolerable levels in agricultural soils. Wheat grain Pb concentrations (0.068-1.36 mg kg(-1)) exceed the prescribed health standard, whereas Sb (<0.05-0.103 mg kg(-1)) and As (<0.05-0.126 mg kg(-1)) concentrations are below the permissible limits fixed for cereals. Of the spontaneously growing plants, Dactylis glomerata L. shows a relatively high root Pb accumulation and a very low Pb translocation, suggesting its feasibility to be used in Pb phytostabilization strategies.

Fetal lead exposure: Encephalopathy in a child

It is well known that lead exposure in the early period of pre pregnancy and antenatal life leads to serious health complications. In this case report, a five month old child who was suffering from encephalopathy was finally confirmed a victim of lead exposure, the source being the environment and the family. We report this case with complete clinical investigation including blood lead analysis. This case report highlights the various ways in which lead may accumulate in the body. It is also aimed at increasing awareness regarding the pathogenesis and clinical manifestations of lead toxicity. The literature survey done reveals that this is the youngest age at which lead toxicity has been documented in India.

Effects of environmental lead contamination on cattle in a lead/zinc mining area: changes in cattle immune systems on exposure to lead in vivo and in vitro

The Republic of Zambia is rich in mineral resources, such as zinc (Zn) and lead (Pb), and mining is a key industry in Zambia. A previous study of Pb pollution in Kabwe, one of the main mining areas, found that soil was contaminated with high levels of toxic metals over a substantial area. In the present study, the authors focus on toxic metal pollution in cattle, one of the most important domestic animals in Zambia. Blood samples from cattle in Kabwe and a control area (Lusaka) were tested for toxic metal content. They also measured mRNA expression of metal-responsive proteins and cytokines in white blood cells using real-time reverse transcriptase polymerase chain reaction. In the present in vitro study, The authors cultured peripheral blood mononuclear cells (PBMCs) from cattle, exposing them to Pb acetate for 24 h and analyzing mRNA expression of metal-responsive proteins and selected cytokines. Lead concentrations in cattle blood from Kabwe were significantly greater than those from Lusaka, as were the mRNA expressions of metallothionein-2 (MT-2), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-1β (IL-1β), IL-6, and inducible nitric oxide synthase (iNOS). The present in vitro study demonstrated that Pb exposure led to an increase in the expressions of MT-2, TNF-α, IL-1β, and iNOS, similar to those found in vivo. These results indicate the possibility of immune system modulations in cattle from the Kabwe area.