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1.
Early lead exposure and childhood adiposity in Mexico city.
Liu, Y, Peterson, KE, Montgomery, K, Sánchez, BN, Zhang, Z, Afeiche, MC, Cantonwine, DE, Ettinger, AS, Cantoral, A, Schnaas, L, et al
International journal of hygiene and environmental health. 2019;(6):965-970
Abstract
BACKGROUND Prenatal and early childhood lead exposures have been associated with reduced weight in infants and young children, while studies that have examined such associations in children during peripubescence are rare. OBJECTIVES We investigated the associations of prenatal and early-life exposure to lead with indices of adiposity in peripubertal children living in Mexico City. METHODS Maternal bone lead (as a proxy for cumulative fetal exposure) was assessed at 1 month postpartum. Blood samples were obtained from children annually from 1 to 4 years. Multivariable linear regression models were used to examine the association between each lead biomarker and BMI z-score, waist circumference, sum of skinfolds and body fat percentage in 248 children aged 8-16 years. RESULTS After adjusting for covariates, maternal patella lead was associated with lower child BMI z-score (β = -0.02, 95% CI: 0.03, -0.01, p = 0.004), waist circumference (β = -0.12 cm, 95% CI: 0.22, -0.03, p = 0.01), sum of skinfolds (β = -0.29 mm, 95% CI: 0.50, -0.08, p = 0.007) and body fat percentage (β = -0.09%, 95% CI: 0.17, -0.01, p = 0.03). No significant associations were detected from the postnatal exposure period. CONCLUSIONS We observed a significant and inverse association of prenatal lead exposure with body composition in Mexican children, suggesting the potential role of early lead exposure in the fetal programming of child growth. Further research on the biological mechanisms underlying these associations is needed.
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2.
Oxidative Stress Indices as Markers of Lead and Cadmium Exposure Toxicity in Auto Technicians in Ibadan, Nigeria.
Omotosho, IO
Oxidative medicine and cellular longevity. 2019;:3030614
Abstract
Auto technicians (auto mechanics, panel beaters, battery chargers, and auto painters) are among the most valuable work force in the society. Reports on oxidative stress in persons occupationally exposed to mixed chemicals abound; however, few have narrowed down specifically on auto technicians, while even fewer have stratified the exposure in the different subgroups of auto technicians. This study evaluated the antioxidant status in auto technicians routinely exposed to lead and cadmium and stratified the results of exposure by different subgroups of auto technicians in Ibadan, Nigeria. Sixty-five apparently healthy males (aged 18 to 65years) were selected based on specific inclusion criteria using a structured questionnaire. Thirty-four were cases consisting of participants routinely working as auto technicians or apprentices(≥2years) while controls were thirty-one nonoccupationally exposed male members of staff/students of the University College Hospital, Ibadan, Nigeria. Blood was collected from all participants and analyzed for the presence of lead, total antioxidant capacity (TAC), and total plasma peroxides (TPP); oxidative stress index (OSI) was calculated. Urine samples collected from all participants were analyzed for the presence of urinary lead and cadmium using standard laboratory methods. Although values of TAC in cases (22538 ± 8726.54) were not statistically different from what was obtained in controls (26741.87 ± 8696.68), TPP and OSI were statistically higher in cases than in controls (183.88 ± 53.39 and 120.16 ± 70.54, respectively, and 0.93 ± 0.45 and 0.49 ± 0.33, respectively). The blood lead level in cases (10.11 ± 4.47) was significantly higher than in controls (7.72 ± 1.22) while elevated urinary lead and cadmium levels were observed in cases (0.65 ± 0.21 and 0.34 ± 0.11, respectively) compared to controls (0.52 ± 0.19 and 0.27 ± 0.10, respectively). Raised TPP and OSI levels-hallmark of active lipid peroxidation-found to be highest among panel beaters compared to others may be prognostic of membrane-damaging diseases in this subgroup of auto technicians.
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3.
Blood Lead Levels and Risk of Atherosclerosis in the Carotid Artery: Results from a Swedish Cohort.
Harari, F, Barregard, L, Östling, G, Sallsten, G, Hedblad, B, Forsgard, N, Borné, Y, Fagerberg, B, Engström, G
Environmental health perspectives. 2019;(12):127002
Abstract
BACKGROUND Lead exposure has been associated with increased incidence of adverse clinical cardiovascular outcomes. Atherosclerosis has been suggested as one of the underlying mechanisms, and findings from experimental studies support this, but human data are scarce. OBJECTIVES Our objective was to determine the association between environmental lead exposure based on blood lead (B-Pb) concentrations and the prevalence of atherosclerotic plaque in the carotid artery. METHODS We used cross-sectional data from the Malmö Diet and Cancer Study cardiovascular cohort (MDCS-CC; recruitment in 1991-1994) covering 4,172 middle-aged men and women. B-Pb at baseline, measured by inductively coupled plasma mass spectrometry, was used as the exposure biomarker. The presence of atherosclerotic plaque in the carotid artery was determined by B-mode ultrasonography. We used logistic regression to estimate odds ratios (ORs) for prevalence of plaque in the carotid artery according to B-Pb quartiles. RESULTS The median B-Pb was 25μg/L (range: 1.5-258), and 36% of the cohort had any atherosclerotic plaque. After controlling for confounders and known cardiovascular risk factors, the OR for prevalence of plaque in the highest quartile (Q4) of B-Pb compared with the lowest quartile (Q1) was 1.35 (95% CI: 1.09, 1.66) in the total group, 1.58 (95% CI: 1.20, 2.08) among women, and 1.18 (95% CI: 0.83, 1.69) among men. Among women, associations were limited to those who were postmenopausal [OR for Q4 vs. Q1=1.72 (95% CI: 1.26, 2.34) vs. OR=0.96 (95% CI: 0.49, 1.89 in premenopausal women)]. Associations were weak and nonsignificant in never-smokers [OR for Q4 vs. Q1=1.14 (95% CI: 0.81, 1.61)]. DISCUSSION Our study shows an association between B-Pb concentrations and occurrence of atherosclerotic plaque in the carotid artery, adding evidence for an underlying pro-atherogenic role of lead in cardiovascular disease. Associations appeared to be limited to postmenopausal (vs. premenopausal) women. https://doi.org/10.1289/EHP5057.
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4.
Concentration-dependent effects of mercury and lead on Aβ42: possible implications for Alzheimer's disease.
Meleleo, D, Notarachille, G, Mangini, V, Arnesano, F
European biophysics journal : EBJ. 2019;(2):173-187
Abstract
Mercury (Hg) and lead (Pb) are known to be toxic non-radioactive elements, with well-described neurotoxicology. Much evidence supports the implication of metals as potential risk cofactors in Alzheimer's disease (AD). Although the action mechanism of the two metals remains unclear, Hg and Pb toxicity in AD could depend on their ability to favour misfolding and aggregation of amyloid beta proteins (Aβs) that seem to have toxic properties, particularly in their aggregated state. In our study, we evaluated the effect of Hg and Pb both on the Aβ42 ion channel incorporated in a planar lipid membrane made up of phosphatidylcholine containing 30% cholesterol and on the secondary structure of Aβ42 in an aqueous environment. The effects of Hg and Pb on the Aβ42 peptide were observed for its channel incorporated into a membrane as well as for the peptide in solution. A decreasing Aβ42 channel frequency and the formation of large and amorphous aggregates in solution that are prone to precipitate were both dependent on metal concentration. These experimental data suggest that Hg and Pb interact directly with Aβs, strengthening the hypothesis that the two metals may be a risk factor in AD.
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5.
Blood levels of cadmium and lead in relation to breast cancer risk in three prospective cohorts.
Gaudet, MM, Deubler, EL, Kelly, RS, Ryan Diver, W, Teras, LR, Hodge, JM, Levine, KE, Haines, LG, Lundh, T, Lenner, P, et al
International journal of cancer. 2019;(5):1010-1016
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Abstract
Cadmium and lead have been classified as carcinogens by the International Agency for Research on Cancer. However, their associations with breast cancer risk are unknown despite their persistence in the environment and ubiquitous human exposure. We examined associations of circulating levels of cadmium and lead with breast cancer risk in three case-control studies nested within the Cancer Prevention Study-II (CPS-II) LifeLink Cohort, European Prospective Investigation into Cancer and Nutrition - Italy (EPIC-Italy) and the Northern Sweden Health and Disease Study (NSHDS) cohorts. Metal levels were measured in stored erythrocytes from 1,435 cases and 1,433 controls using inductively coupled plasma-mass spectrometry. Summary relative risks (RR) and 95% confidence intervals (CI) were calculated using random-effects models with each study result weighted by the within- and between-study variances. I2 values were calculated to estimate proportion of between study variation. Using common cut-points, cadmium levels were not associated with breast cancer risk in the CPS-II cohort (continuous RR = 1.01, 95% CI 0.76-1.34), but were inversely associated with risk in the EPIC- Italy (continuous RR = 0.80, 95% CI 0.61-1.03) and NSHDS cohorts (continuous RR = 0.73, 95% CI 0.54-0.97). The inverse association was also evident in the meta-analysis (continuous RR = 0.84, 95% CI 0.69-1.01) with low between-study heterogeneity. Large differences in lead level distributions precluded a meta-analysis of their association with breast cancer risk; no associations were found in the three studies. Adult cadmium and lead levels were not associated with higher risk of breast cancer in our large meta-analysis.
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Chromium and Lead adsorption by avocado seed biomass study through the use of Total Reflection X-Ray Fluorescence analysis.
Boeykens, SP, Redondo, N, Obeso, RA, Caracciolo, N, Vázquez, C
Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine. 2019;:108809
Abstract
Adsorption is an effective method for the treatment of wastewater containing low concentrations of heavy metals. This kind of metals such as Chromium and Lead could affect health and the ecosystem. In this work, biomass of avocado seed was used as adsorbent. It was tested as adsorbent in natural form (NB), as a chemically activated (AB) form and as activated carbon (AC). Batch reactors were used to investigate the adsorbent efficiency. Concentration of metal ions was measured using Total Reflection X-Ray Fluorescence. Operational conditions influencing adsorption, such as: pH, adsorbent dose, initial concentration and contact time, were measured and controlled. The 80% of adsorption was reached, at pH: 5 and 25 °C, when were used 50 mL of: a 20 mg L-1 of Cr (VI) solution with a dose of 1.25 g of NB, a 30 mg L-1 of Pb (II) solution with a dose of 0.15 g of NB, a 50 mg L-1 Pb (II) solution with a dose of 0.15 g of AB, a 30 mg L-1 Cr (VI) solution with a dose of 0.35 g of AB, a 30 mg L-1 of both metals, with a dose of 0.15 g of AC for Pb (II) and 0.7 g of AC for Cr (VI). In all cases, the pH value before and during the experiments remained constant, indicating the lack of acid/base reactions during the processes. The Langmuir adsorption isotherm model best fitted to the experimental data. The experimental results from kinetic studies best correlated using the pseudo-second order model. An increase in the remotion of both ions (Pb (II) and Cr (VI)), was observed when comparing the results obtained using the activated biomass. However, considering the loss of biomass that the pre-treatment causes, the remotion per gram of initial biomass does not vary significantly.
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Screening for Elevated Blood Lead Levels in Childhood and Pregnancy: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force.
Cantor, AG, Hendrickson, R, Blazina, I, Griffin, J, Grusing, S, McDonagh, MS
JAMA. 2019;(15):1510-1526
Abstract
IMPORTANCE Elevated blood lead level is associated with serious, often irreversible, health consequences. OBJECTIVE To synthesize evidence on the effects of screening, testing, and treatment for elevated blood lead level in pregnant women and children aged 5 years and younger in the primary care setting to inform the US Preventive Services Task Force. DATA SOURCES Cochrane CENTRAL and Cochrane Database of Systematic Reviews (through June 2018) and Ovid MEDLINE (1946 to June 2018); surveillance through December 5, 2018. STUDY SELECTION English-language trials and observational studies of screening for and treating elevated lead levels in asymptomatic children and pregnant women. DATA EXTRACTION AND SYNTHESIS Independent critical appraisal and data abstraction by 2 reviewers using predefined criteria. MAIN OUTCOMES AND MEASURES Elevated blood lead level, morbidity, mortality, clinical prediction tools, test accuracy, adverse events. RESULTS A total of 24 studies (N = 11 433) were included in this review. No studies evaluated the benefits or harms of screening vs no screening in children. More than 1 positive answer on the 5-item 1991 Centers for Disease Control and Prevention (CDC) screening questionnaire was associated with a pooled sensitivity of 48% (95% CI, 31.4% to 65.6%) and specificity of 58% (95% CI, 39.9% to 74.0%) for identifying children with a venous blood lead level greater than 10 μg/dL (5 studies [n = 2265]). Adapted versions of the CDC questionnaire did not demonstrate improved accuracy. Capillary blood lead testing demonstrated sensitivity of 87% to 91% and specificity greater than 90%, compared with venous measurement (4 studies [n = 1431]). Counseling and nutritional interventions or residential lead hazard control techniques did not reduce blood lead concentrations in asymptomatic children, but studies were few and had methodological limitations (7 studies [n = 1419]). One trial (n = 780) of dimercaptosuccinic acid (DMSA) chelation therapy found reduced blood lead levels in children at 1 week to 1 year but not at 4.5 to 6 years, while another trial (n = 39) found no effect at 1 and 6 months. Seven-year follow-up assessments showed no effect on neuropsychological development, a small deficit in linear growth (height difference, 1.17 cm [95% CI, 0.41 to 1.93]), and poorer cognitive outcomes reported as the Attention and Executive Functions subscore of the Developmental Neuropsychological Assessment (unadjusted difference, -1.8 [95% CI, -4.5 to 1.0]; adjusted P = .045) in children treated with DMSA chelation. Evidence was too limited to determine the accuracy of screening questionnaires or benefits and harms of treatment in pregnant women. CONCLUSIONS AND RELEVANCE Screening questionnaires were not accurate for identifying children with elevated blood lead levels. Chelating agents in children were not significantly associated with sustained effects on blood level levels but were associated with harms.
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Exposure routes and health effects of heavy metals on children.
Al Osman, M, Yang, F, Massey, IY
Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine. 2019;(4):563-573
Abstract
Heavy metals are naturally existing elements that have relatively high atomic weight and a minimum density five times the density of water. Heavy metals have extensive applications in industries, homes, agriculture and medicine, leading to their wide distribution in the environment. Most heavy metals are reported to be highly toxic. They also have numerous exposure routes, including ingestion, inhalation, and dermal absorption, subsequently inducing some health effects resulting from human and heavy metals contact. The implications of heavy metals with regards to children's health have been noted to be more severe compared to adults. The element's harmful consequences on children health include mental retardation, neurocognitive disorders, behavioral disorders, respiratory problems, cancer and cardiovascular diseases. Much attention should be given to heavy metals because of their high toxicity potential, widespread use, and prevalence. This review therefore examines the exposure routes and health effects of mercury (Hg), lead (Pb), chromium (Cr), cadmium (Cd), and barium (Ba) on children. In addition, their toxic mechanisms are elucidated.
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Optimal ranges of variables for an effective adsorption of lead(II) by the agricultural waste pomelo (Citrus grandis) peels using Doehlert designs.
Yu, XL, He, Y
Scientific reports. 2018;(1):729
Abstract
The capacity of pomelo peels' adsorption on lead(II) from aqueous solutions without modifications was investigated and confirmed. Four variables in this study, pH, temperature, time and initial concentration of lead(II), significantly affected the adsorption rate of pomelo peels. The prediction model and optimal ranges of optimized variables were given by Doehlert designs, which made the selection of variables rapid, flexible and effortless to obtain an adsorption rate reaching 99.9% and 20 mg/L for initial lead(II) concentration, 3 for pH, 50 °C for temperature and 210 min for time was a choice. The higher correlation coefficient as well as the more consistent value of experimental equilibrium adsorption capacity of the pseudo-first-order model suggested it bore a better prediction of the adsorption kinetics than the pseudo-second-order model. Langmuir model indicated the adsorption mechanism of pomelo peels was monolayer sorption with the help of both physical adsorption and chemical bonding, which were demonstrated by scanning electron microscopy and Fourier transform-infrared, respectively. The ability of pomelo peels to adsorb lead(II) from aqueous solutions was not interfered with the presence of calcium(II), magnesium(II), copper(II) and zinc(II). Pomelo peels had the potential to be utilized in the simultaneous adsorption of toxic heavy metal ions.
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Ultrasonic seed treatment improved physiological and yield traits of rice under lead toxicity.
Rao, G, Ashraf, U, Huang, S, Cheng, S, Abrar, M, Mo, Z, Pan, S, Tang, X
Environmental science and pollution research international. 2018;(33):33637-33644
Abstract
Lead (Pb) is a highly toxic metal that damages normal plant metabolism and often results in reduced crop growth and yield. To measure whether or not ultrasonic seed (US) treatment alleviates Pb stress in rice, the seeds of two rice cultivars, i.e., Guangyan1 and Huahang31, were exposed to 30 min of ultrasonic vibration and then the seedlings were transplanted to Pb-contaminated soil. Results revealed that the Pb contents in roots, stems, leaves, panicles (at heading), and brown rice (at maturity) were lower in US treatment than control (CK; without US treatment); the trend for accumulation of Pb in different plant parts was recorded as: root ˃ stems ˃ leaves ˃ panicles ˃ brown rice in both rice cultivars. Overall, the Pb contents in the brown rice of Huahang31 were higher than those in Guangyan1. Moreover, the contents of proline and soluble protein as well as the activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) were significantly higher while the malondialdehyde (MDA) contents were significantly reduced in US treatment compared to CK. The effective panicle number, seed set percentage, grains per panicle, 1000-grain weight, and grain yield were increased by 8.9%, 5.3%, 6.8%, 4.4%, and 26.6% in Guangyan1 and 3.2%, 5.7%, 5.7%, 5.0%, and 24.2% in Huahang31, respectively in US treatment compared to CK. Hence, seed treatment with ultrasonic waves could improve rice performance and reduce brown rice Pb accumulation under Pb-polluted soils.