Maternal and neonatal scalp hair concentrations of zinc, copper, cadmium, and lead

Postpartum scalp hair samples from 82 term-pregnancy mother/neonate pairs were analyzed for their concentration of zinc (Zn), copper (Cu), cadmium (Cd), and lead (Pb), using inductively coupled plasma-mass spectrometry. Maternal and neonatal Zn concentrations had geometric means (and 99% confidence intervals) of 122.5 μg/g (117.9–131.5 μg/g) and 146.9 μg (141.5–156.7 μg/g) respectively. Corresponding Cu values were 18.4 μg/g (17.6–23.8 μg/g) and 6.7 μg/g (6.3–7.6 μg/g). Those of Cd were 0.49 μg/g (0.47–0.69 μg/g) in the mothers and 0.57 μg/g (0.55–0.86 μg/g) in the neonates. For Pb, they were 7.95 μg/g (7.60–9.32 μg/g) and 4.56 μg/g (4.39–5.56 μg/g). Cigaret smoking, despite its relatively low prevalence (19.5%), was associated with lower Zn and higher Cd and Pb concentrations and in lower Zn/Cd and Zn/Pb molar concentration ratios. Smoking also altered interelemental relationships, particularly those of Zn with Cd and Pb and those between Cd and Pb. Smoking frequency appeared to show negative dose-response effects on maternal and neonatal Zn concentrations, Zn/Pb molar concentration ratios, and birth weight. Mothers with a history of oral contraceptive (OC) usage had significantly higher Cu concentrations and lower Zn/Cu molar concentration ratios than nonusers, with the highest Cu concentrations and lowest Zn/Cu values being associated with third-generation OCs. No similar effects were elicited in the respective neonatal Cu concentrations. Neither alcohol consumption nor prenatal supplementation with iron and/or folic acid had discernible effects on the maternal or neonatal elemental concentrations. The data from this study suggest that in a given population of term-pregnancy mothers and neonates, significant interindividual variations in hair trace element concentrations can occur, irrespective of commonality of general environment, and that lifestyle factors, including cigaret smoking and OC usage history, can be significant contributory factors to such variations. The data are discussed in relation to the effects of smoking-associated exposure to Cd and Pb exposure on Zn availability for placental transfer, as well as on the quantitative maternal Zn supply levels to the fetus resulting from the known tendency of smokers to have lower dietary intakes of Zn. The higher Cu concentrations in OC users are discussed in relation to altered Cu metabolism, characterized by increased synthesis of the Cu-binding protein, ceruloplasmin, as an acute-phase antioxidant response to altered lipid profile and increased lipid oxidation.     

Characterization and Distribution of the Selected Metals in the Scalp Hair of Cancer Patients in Comparison with Normal Donors

Eighteen metals were estimated in the scalp hair samples from cancer patients (n = 111) and normal donors (n = 113). Nitric acid–perchloric acid wet digestion procedure was used for the quantification of the selected metals by flame atomic absorption spectrophotometry. In the scalp hair of cancer patients, highest average levels were found for Ca (861 μg/g), followed by Na (672 μg/g), Zn (411 μg/g), Mg (348 μg/g), Fe (154 μg/g), Sr (129 μg/g), and K (116 μg/g), whereas in comparison, the dominant metals in the scalp hair of normal donors were Ca (568 μg/g), Zn (177 μg/g), Mg (154 μg/g), Fe (110 μg/g), and Na (103 μg/g). The concentrations of Ca, Cd, Co, Cr, Fe, K, Mg, Mn, Na, Ni, Pb, Sb, Sr, and Zn were notably higher in the hair of cancer patients as compared with normal donors, which may lead to a number of physiological disorders. Strong positive correlations were found in Mn–Pb (0.83), Cd–Cr (0.82), Cd–Li (0.57), Fe–Pb (0.56), and Fe–Mn (0.55) in the hair of cancer patients whereas Na–Cd, Li–Cr, Li–Co, Co–Cd, Li–Cd, Na–Co, Na–Li, Ca–Mg and Na–Cr exhibited strong relationships (r > 0.50) in the hair of normal donors. Principal Component Analysis (PCA) of the data revealed seven PCs, both for cancer patients and normal donors, but with significantly different loadings. Cluster Analysis (CA) was also used to support the PCA results. The study evidenced significantly different pattern of metal distribution in the hair of cancer patients in comparison with normal donors. The role of trace metals in carcinogenesis was also discussed.     

Changes in fatty acid composition of lipids from birds, rodents, and preschool children exposed to lead

Chronic treatment with inorganic lead (Pb) has been shown to increase the proportion of arachidonic acid (ArA), as well as the arachidonate/linoleate (ArA/LA) ratio, in the fatty acids of lipids from a variety of avian tissues. Changes in two fatty acid-mediated phenomena, peroxidation of membrane lipids and synthesis of eicosanoid cytokines, are associated with this enhanced ArA content. The authors are not aware of any reports in the literature in which these effects of Pb have been described for any animals other than birds. In the current study, the authors investigated the effect of Pb on lipid metabolism in three species: avian, rodent, and human. The group of children identified as suffering environmental Pb exposure were from a Pb-surveillance program and had blood Pb concentrations (PbB) averaging 23 μg/dL. Turkey poults fed 100 ppm dietary Pb as Pb acetate-trihydrate for 19 d had a PbB of 46 μg/dL. Gastric intubation of rats with 80 mg Pb/kg/d for 10 d resulted in a PbB of 74 μg/dL. We analyzed fatty acid composition of whole blood from children, poults, and virgin rats. Low-dose (nongrowth inhibitory) Pb exposure resulted in significantly increased ArA concentration and ArA/LA ratio in blood from all species. Also analyzed were plasma and liver of poults, virgin rats, and pregnant rats and their fetuses. In plasma and liver from Pb-treated poults and virgin rats, ArA and the ArA/LA ratio were again enhanced. Pb intoxication also affected ω3 composition, increasing the concentrations of all long-chain ω3 fatty acids of fetuses from Pb-treated pregnant dams. The authors propose that altered fatty acid metabolism may be responsible for some indications of Pb poisoning. Possible consequences mediated through lipid peroxidation and production of ArA-derivative eicosanoids are considered.     

Biomonitoring of Lead and Cadmium in the Hair and Fingernails of Elderly Korean Subjects

Lead and cadmium are toxic to humans at excessive levels, and monitoring the human body burden of these metals is important in preventing adverse health effects. In this study, we assessed the exposure to lead and cadmium among an elderly population 60 years of age or older. Based on data from 115 participants, we found that the geometric mean lead concentrations in hair and fingernails were 1.11 μg/g [95% confidence interval (CI) 0.78–1.58] and 1.11 μg/g (95% CI 0.81–1.51), respectively. The lead concentrations in hair and fingernails were significantly related to cigarette smoking. The geometric mean cadmium concentrations in hair and fingernails were 52.6 ng/g (95% CI 42.0–65.9) and 40.1 ng/g (95% CI 29.9–53.9), respectively. Cadmium concentrations in hair were significantly related to body mass index and cigarette smoking, whereas higher fingernail cadmium concentrations were related to alcohol drinking. Correlations between hair and fingernail concentrations of lead and of cadmium were slightly positive. Our findings suggest that the body burden of lead and cadmium varies according to demographic factors, and hair and fingernails could be used differentially as a biological medium for metal exposure.     

Small-scale Gold Mining in the Puyango River Basin,Southern Ecuador: A Study of Environmental Impacts andHuman Exposures

This study addresses the impact of small-scale gold mining on the environment and communities of the Puyango River basin in the southwest of Ecuador between 1999 and 2001. Our primary objectives were to measure mercury, manganese, and lead in the river, to identify pathways of population exposure, and biological indicators of human exposure. A multi-method design at the catchment scale was applied to the analysis of water, sediments, and particulate matter for mercury, lead, and manganese over two different seasons. A household survey was undertaken, and individuals were assessed for lead (blood samples), and for mercury (urine and hair samples). River water samples had high concentrations of particulate matter (700 mg/L). Mercury and lead levels in water at the gold processing plants were very high in both seasons (250 ng Hg/L and 160 μg Pb/L). Mercury and lead, there was a downstream gradient with the areas adjacent to the gold processing plants having the highest levels. In Portovelo, the Upper Basin city, 14% of the population reported occupational exposure to inorganic mercury. Although no one in Portovelo consumes water from the river, 10% of the population consume local fish. This contrasts the Lower Basin where 98% of the population consume fish, and 100% use river water for drinking and cooking. Lead blood levels over 20 μg/dl were found in 39.4% of the study population and blood mercury over 10 μg/L only in 10.0%. Urinary mercury over 4 μg/L was found in 66.5% of the examined persons. Hair methylmercury did not exceed the safe limit of 2 μg/g, the mean concentration was 1.2 μg/g. Mining activity and erosion contributes to heavy-metal contamination (mercury, lead, and manganese) throughout the Puyango Basin. The relation between environmental contamination is complex and further research is being conducted to understand these relations.     

Lead Dysregulates Serine/Threonine Protein Phosphatases in Human Neurons

It is well established that lead (Pb) exposure in humans leads to learning and memory impairment. However, the biological and molecular mechanisms are still not clearly understood. When over activated, serine/threonine protein phosphatases are known to function as a constraint on learning and memory. Activation of these phosphatases can also result in cytoskeletal changes that will adversely affect learning and memory. We investigated the effects of Pb exposure on these phosphatases in primary cultures of human neurons. Neurons were exposed to physiologically relevant concentrations of Pb (5, 10, 20 and 40 μg/dL) and total phosphatase and PP2A activities were determined in neuronal lysate using para-nitrophenyl phosphate (pNPP), and a PP2A-specific phosphopeptide as substrates. Expression of various serine/threonine phosphatases, tau and its phosphorylation state were determined by Western blot (WB) and immunocytochemistry (ICC). We found that the total phosphatase activity in the neuronal lysate was increased by 30–50% by all the concentrations of Pb tested. PP2A activity was increased by 5 μg/dL Pb only. PP1 expression was increased (ranging from 25–50%) by 10, 20 and 40 μg/dL of Pb. PP2B expression was increased substantially (up to 2.5-fold) by 10 μg/dL Pb, whereas, higher concentrations did not show any effect. On the other hand, Pb (at all concentrations used) decreased expression of PP2A and PP5. Pb exposure induced substantial hyperphosphorylation of tau at serine 199/202 by 5 and 10 μg/dL Pb, and Threonine 231 at higher doses. Expression of total tau was mostly unaffected by lead. Immunocytochemistry data confirmed the WB results of expression of PP1, PP2A, tau protein and the phosphorylation of tau. These results support our hypothesis that Pb exposure up regulates some of the serine/threonine phosphatases (PP1 and PP2B) that are known to impair memory formation, and suggest a novel mechanism of Pb neurotoxicity.     

Induction of metallothionein in rat tissues following subchronic exposure to mercury shown by radioimmunoassay

Although the analysis of metallothionein (MT) by radioimmunoassay (RIA) is not a common technique, its use is preferred over other methods since it offers the advantages of sensitivity and specificity. In this paper we present data on the basal levels of MT in rat tissues and physiological fluids of female Sprague-Dawley rats. The mean basal MT concentrations of the following organs and fluids were determined by RIA to be: liver (9.8 μg/g), kidney (68 μ/g), brain (0.8 μg/g), spleen (1.0 μg/g), heart (5.4 μg/g), plasma (11 ng/ml), and urine (200–300 μg/g creatinine). Following subcutaneous exposure to inorganic mercury (0.2 μmol/kg/d, 5 d a week for up to 4 wk), the metal accumulated primarily in the kidney. There was also a simultaneous accumulation of zinc in the liver and of zinc and copper in the kidney. Induction of MT did take place in liver, kidney, brain, and spleen. No increases in the MT contents of blood and urine were noted. The excess zinc and copper in the kidney of exposed animals were found to be associated predominantly with MT. No overt signs of mercury toxicity were noted in these animals and the incidence of proteinurea was nil. The data are discussed with reference to methods of MT determination in animal tissues and in relation to mercury metabolism and toxicity.     

Effect of lead ions on rat erythrocyte purine content

The influence of short-term exposure to lead on the energetic status of erythrocytes in rats is reported in this study. The male Wistar rats selected for this study drank water containing 1% lead(II) acetate and/or intraperitoneal injections of 1 or 2 mg/kg body wt every 4 d starting on the eighth of the experiment, over a period of 1 mo. The whole-blood lead concentration measured after 4 wk was 1.51–35.31 μg/dL. The concentrations of adenosine, adenosine triphosphates, diphosphates, and monophosphates (ATP, ADP, and AMP), guanine triphosphates, diphosphates and monophosphates (GTP, GDP, and GMP), guanosine (Guo), inosine (Ino), inosine monophosphate (IMP), hypoxantine (Hyp), and nicotinamide dinucleotide and its phosphate (NAD⁺ and NADP⁺) were determined by high-performance liquid chromatography (HPLC). The mean concentrations of ATP, GTP, NAD⁺, and NADP⁺ and those of adenylate (AEC) and guanylate (GEC) were significantly reduced in erythrocytes from the animals exposed to lead when compared to untreated controls. These results suggest that a lead ion disrupts the erythrocyte energy pathways. The decreases of NAD⁺ and ATP could be used as an indicator of the extent of exposure to low levels of lead.     

Lead and catechol hematotoxicity in vitro using human and murine hematopoietic progenitor cells

In vitro cloning assays for hematopoietic myeloid and erythroid precursor cells have been used as screening systems to investigate the hematotoxic potential of environmental chemicals in humans and mice. Granulocyte-monocyte progenitors (CFU-GM) from human umbilical cord blood and from mouse bone marrow (Balb/c and B6C3F1) were cultured in the presence of lead and the benzene metabolite catechol. Erythroid precursors (BFU-E) from human umbilical cord blood were cultured in the presence of lead. The in vitro exposure of the human and murine cells resulted in a dose-dependent depression of the colony numbers. The concentration–effect relationship was studied. Results showed that: (1) Based on calculated IC50 values, human progenitors are more sensitive to lead and catechol than are murine progenitors. The dose that caused a 50% decrease in colony formation after catechol exposure was 6 times higher for murine cells (IC50 = 24 μmol/L) than for human cord blood cells (IC50 = 4 μmol/L). Lead was 10–15 times more toxic to human hematopoietic cells (IC50 = 61 μmol/L) than to murine bone marrow cells from both mice strains tested (Balb/c, IC50 = 1060 μmol/L; B6C3F1, IC50 = 536 μmol/L). (2) A lineage specificity was observed after exposure to lead. Human erythroid progenitors (hBFU-E) (IC50 = 3.31 μmol/L) were found to be 20 times more sensitive to the inhibitory effect of lead than were myeloid precursors (hCFU-GM) (IC50 = 63.58 μmol/L). (3) Individual differences in the susceptibility to the harmful effect of lead were seen among cord blood samples. (4) Toxicity of lead to progenitor cells occurred at environmentally relevant concentrations. This revised version was published online in July 2006 with corrections to the Cover Date.     

Accumulation of Cd and Pb in successive stages ofGalleria mellonella and metal transfer to the pupal parasitoidPimpla turionellae

Larvae ofGalleria mellonella L. (Lepidoptera, Pyralidae) were exposed to Pb (4, 43, 430 μg Pb/g food dw) and Cd (4, 20, 40 μg Cd/g food dw) applied singly and in combination. Metal transfer of Pb and Cd was investigated from food to larvae and successive stages ofG. mellonella and also to the pupal parasitoidPimpla turionellae L. (Hymenoptera, Ichneumonidae). Larvae/food concentration factors (CFs) were highest in controls (Cd 5.25, Pb 3.07) and ranged from 0.19 to 0.92 for Cd and from 0.18 to 0.83 for Pb in contaminated groups; in general, the CFs decreased with an increasing contamination level in food.G. mellonella eliminated most of its larval metal load before pupation (metal concentration in larvae ς> pupae). Although pupae were only moderately contaminated (0.11–1.61 μg Cd/g dw), concentrations inP. turionellae ranged from 0.5 to 6.8 μg Cd/g dw. Again, CFs (parasitoid/pupa) decreased with enhanced levels of metal in the host pupae (Cd 3.07–14.05, Pb 0.0–2.47). The CFs calculated for both species were lower at combined contamination compared to single application.G. mellonella can be classified as a ‘deconcentrator’ (CF<1) along with other lepidopteran species, whereasP. turionellae is apparently a ‘macroconcentrator’ (CF>2).     

Comparison of Trace Elements in the Scalp Hair of Malignant and Benign Breast Lesions Versus Healthy Women

Trace elements including Al, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sb, Sr, and Zn were analyzed in the scalp hair samples of women with malignant breast lesions, women with benign breast lesions, and healthy donors using atomic absorption spectrophotometric method. In the scalp hair of malignant-tumor patients, the highest average concentration was shown by Ca (1,187 μg/g), followed by Na (655 μg/g), Mg (478 μg/g), Zn (391 μg/g), Sr (152 μg/g), Fe (114 μg/g), and K (89.8), while in the case of benign-tumor patients, the average estimated element levels were 1,522, 1,093, 572, 457, 217, 80.4, and 74.7 μg/g, respectively. Most of the elements exhibited non-normal distribution evidenced by large spread, standard error, and skewness values. Mean concentrations of Ca (634 μg/g), Zn (206 μg/g), Mg (162 μg/g), Fe (129 μg/g), and Na (82.1 μg/g) were noteworthy in the scalp hair of healthy women. Average levels of Na, Sr, K, Cd, Co, Pb, Mg, Ca, Zn, Ni, Sb, and Mn were revealed to be significantly higher in the hair of malignant and benign patients compared to the healthy women; however, Fe, Cu, Al, and Cr were not significantly different in the scalp hair of the three groups. The quartile distributions of Ca, Cd, Co, Cr, K, Mg, Mn, Na, Ni, Pb, Sb, and Sr revealed maximum spread in the scalp hair of malignant and benign groups; nevertheless, Al, Cu, Fe, and Zn exhibited almost comparable quartile levels in the three groups. Strong correlation coefficients were found between Fe and Cd, Al and Na, Mn and Sr, Co and Cr, Cd and Cr, Pb and K, Pb and Mn, Cu and Na, and Al and Fe in the scalp hair of malignant-tumor patients, while Fe and K, Cd and Co, Na and Co, and Cr and Pb showed strong correlations in the scalp hair of benign-tumor patients, both of which were significantly different compared with the healthy subjects. Multivariate cluster analysis also revealed divergent clustering of the elements in the scalp hair of malignant and benign patients in comparison with the healthy women.     

Advantages of the Use of Deciduous Teeth,Hair, and Blood Analysis for Lead and Cadmium Bio-Monitoring in Children. A Study of 6-Year-Old Children from Krakow (Poland)

The population of about 300 6-year-old preschool children was studied for lead (Pb) and cadmium (Cd) in deciduous teeth, scalp hair, and capillary blood. Zinc (Zn) content in hair was also measured due to its possible interferences with the elements studied. The Pb and Cd contents were measured by graphite furnace atomic absorption spectrometry with Zeeman background correction, and Zn, by flame method. Metal levels found were comparable to those in European countries. Positive correlations between Pb and Cd in the same and different tissues were widespread (r = 0.23–0.68). A positive correlation was found between Pb in teeth and blood (r = 0.65, p < 0.001). Pb blood threshold 100 μg L⁻¹ referred to 2.6 μg g⁻¹ Pb in teeth. Predictability of this Pb teeth limit was 14% vs. 5% for Pb blood. Strong negative correlation was found between hair Pb and Zn (r = −0.68, p < 0.001). Enhanced Cd and Zn levels in hair were associated with the household drinking water hardness. The associations with some other environmental and behavioral factors were also presented and discussed. The results proved the advantage of analysis of primary teeth for Pb exposure screening of preschool children.     

Effect of diabetes on trace-element concentration of blood

The effect of diabetes on trace elements concentration in blood of experimental animals has been studied by thin-target X-ray fluorescence analysis. Balb/C young adult mice, 6–8 wk old, were used in the study. About 100–200 μL venous blood was taken from each mouse for trace element analysis. The measurements were carried out on a commercial Wave-Length-Dispersive XRF System, with different X-ray tubes being used for maximizing the detection sensitivity of different groups of elements. Later on, the mice were made diabetic by an intravenous injection of Streptozotocin (250 mg/kg). Then, 2 and 3 wk after the injection, 100 μL of venous blood was drawn from each of the mice and analyzed for trace element concentration. In this way we were able to study the changes in blood trace elements caused by diabetes. The results and advantages of using experimental animals, under controlled conditions, to study trace element variations caused by different diseases, are discussed in the paper.     

Lead and Cadmium Co-exposure Mediated Toxic Insults on Hepatic Steroid Metabolism and Antioxidant System of Adult Male Rats

The redox status and steroid metabolism of liver of adult male rat exposed to lead (Pb) and cadmium (Cd) either alone or in co-exposure (0.025 mg/kg body weight intraperitoneally/15 days) was studied. Pb and Cd significantly accumulated in the liver. The activity of steroid metabolizing enzymes 17-βhydroxysteroid oxidoreductase and uridine diphosphate–glucuronyltransferase were decreased in experimental animals. 17-β-Hydroxysteroid dehydrogenase was reduced to 33%, 38%, and 24% on treatment of Pb, Cd, and co-exposure (Pb + Cd). Furthermore, the activity of uridine diphosphate–glucuronosyltransferase was significantly reduced to 27% (Pb exposure), 36% (Cd exposure), and 25% (co-exposure of Pb + Cd). Cd exposure exhibited more toxic effect than Pb, while co-exposure demonstrated the least. The activities of antioxidant enzymes, superoxide dismutase, catalase, glutathione reductase, and glucose-6-phosphate dehydrogenase decreased and glutathione peroxidase increased in mitochondrial and post-mitochondrial fractions. The level of lipid peroxidation increased, and cellular glutathione concentration decreased. Hepatic DNA was decreased, whereas RNA content and the activity of alanine transaminase remained unchanged. Histological studies revealed that only Cd-exposed groups exhibited cytotoxic effect. These results suggest that when Pb and Cd are present together in similar concentrations, they exhibited relatively decreased toxic effect when compared to lead and cadmium in isolation with regard to decreased steroid metabolizing and antioxidant enzyme activities. This seems that the toxic effect of these metals is antagonized by co-exposure due to possible competition amongst Pb and Cd for hepatic accumulation.     

Lead biogeochemistry in a central Ontario Forested watershed

To determine the sources and sinks of atmospherically deposited Pb at a forested watershed (Plastic Lake) in central Ontario, Canada, Pb pools and fluxes through upland, wetland and lake compartments were measured during 2002/2003 and compared with previous measurements taken between 1989 and 1991. In 2002/2003, annual bulk deposition of Pb was 0.49 mg m⁻² compared with 1.90–1.30 mg m⁻² in 1989–1991. Annual Pb concentrations in stream water draining the upland part of the catchment were very low (0.04 μg l⁻¹) and were approximately half those measured in 1989–1991 (0.11–0.08 μg l⁻¹). Leaching losses in stream water were small and mass balance estimates indicate almost complete retention (>95%) of atmospherically deposited Pb in upland soils. In contrast, annual Pb concentrations in stream water draining a wetland were between 0.38 and 0.77 μg l⁻¹, with the highest concentration occurring in 2002/2003 and mass balance calculations indicate that the wetland is a net source of Pb in all measured years. Lead concentrations in the lake outflow were low and the average Pb concentration measured in 2002/2003 (0.09 μg l⁻¹) was approximately half the value recorded in 1989–1991 (0.19 μg l⁻¹ both years). Annual mass balance estimates indicate that the lake retained between 2.47 mg m⁻² (1989/1990) and 1.42 mg m⁻² (2002/2003) and that in 2002/2003 68% of the Pb input to the lake is derived from the terrestrial catchment. These estimates are higher than sediment core records, which indicate around 18 mg m⁻² Pb was retained in sediment during the 1990s. Nevertheless, Pb concentrations decrease with sediment depth and ²⁰⁶Pb/²⁰⁷Pb concentrations increase with depth, a pattern also observed in mineral soils that reflects the substantial contribution of anthropogenic Pb to the watershed. Lead isotope data from soil and sediment indicate a recent anthropogenic Pb signal (²⁰⁶Pb/²⁰⁷Pb ∼ 1.185) in upper soils and sediments and an older anthropogenic signal (²⁰⁶Pb/²⁰⁷Pb ∼ 1.20) in deeper soil and sediment. Lead isotope data in sediment and vegetation indicate that practically all the Pb cycled in the forest at Plastic Lake is anthropogenic in origin.     

Increased Lipid Peroxidation and Ascorbic Acid Utilization in Testis and Epididymis of Rats Chronically Exposed to Lead

The hypothesis has been recently presented that lead may exert its negative effect at least partially through the increase of reactive oxygen species (ROS) level in tissues. However, little is known about the influence of lead intoxication on equilibrium between generation and elimination of ROS in the male reproductive system. Sexually mature male Wistar rats were given ad libitum 1% of aqueous solution of lead acetate (PbAc) for 9 months. Significantly higher lead concentrations were found in blood [median 7.03 (Q25–Q75: 2.99–7.65) versus 0.18 (0.12–0.99) μg dl⁻¹, P < 0.01], caput epididymis [median 5.51 (Q25–Q75: 4.31–7.83) versus 0.51 (0.11–0.80) μg g⁻¹ d.m., P < 0.001], cauda epididymis [median 5.88 (Q25–Q75: 4.06–8.37) versus 0.61 (0.2 – 1.08) μg g⁻¹ d.m., P < 0.001] and testis [median 1.81 (Q25–Q75: 0.94–2.31) versus 0.17 (0.03–0.3) μg g⁻¹ d.m., P < 0.01] of lead-intoxicated rats when compared to the control. The concentration of ascorbyl radical, generated in vitro from l-ascorbic acid (present in tissues in vivo) was measured by means of Electron Paramagnetic Resonance (EPR) spectroscopy. The EPR signal of ascorbyl radical in caput epididymis, cauda epididymis, testis and liver of lead acetate-treated animals revealed a significant decrease by 53%, 45%, 40% and 69% versus control tissues, respectively. Plasma l-ascorbic acid content measured by high performance liquid chromatography (HPLC) method and total antioxidant status (TAS) measured by means of spectrophotometry were also significantly lower in the intoxicated versus control animals (28% and 21%, respectively). In the group exposed to lead the concentration of lipid peroxide in homogenates of the reproductive system organs was significantly elevated versus control group. It can be assumed that the lower EPR signal was caused by decreased tissue concentrations of l-ascorbic acid. The latter may have resulted from consumption of ascorbic acid for scavenging of ROS excess in tissues of animals chronically exposed to lead.     

Determination of copper and zinc levels in human hair

The Cu and Zn levels of both 607 men (1–85 y old) and 649 women (1–92 y old) were determined by atomic absorption spectrometry. Sex does not influence Cu (14.89±0.89 μg/g and 15.26±0.79 μg/g hair for males and females, respectively) and Zn contents (200.97±9.68 μg/g for men and 209.81±9.49 μg/g hair for women). Age influences Cu and Zn concentrations, but only significantly in females: Cu levels decrease over 60 y of age; whereas Zn levels increase significantly from age groups 2–5 to 20–40 years. Hair color influences Cu concentrations in both males and females. In males, white hair containes less Cu than black hair; in females, white hair's Cu levels are significantly lower than those of dark blond, red, light brown, and brown hair. There are no significant differences in Zn concentrations with respect to different hair colors, in either males or females.     

Influence of glutathione on zinc-mediated cellular toxicity

The effect of zinc on various pulmonary cell lines has been studied by measuring the depletion of total cellular glutathione after exposure to zinc(II) chloride at different concentrations. Total cellular glutathione (cGS) was measured at 31 ± 3 nmol/mg, 3.8 ± 0.6 nmol/mg, and 3.7 ±1.2 nmol/mg protein in A549, L2, and 11Lu cells, respectively. After treatment with buthionine sulfoximine (BSO), the cGS levels decreased by 20% in A549 cells and below 0.2 nmol/mg in L2 and 11Lu cells. Exposure of A549 cells to 25–200 μM ZnCl₂ for 4 h alone decreased the cGS content to 60–80%. There was little additional effect in BSO-pretreated cells. In L2 and 11Lu cells, the decrease of cGS was 70–85% following exposure to 15–150 μM ZnCl₂ for 2 h. If BSO was also used, the decrease in cGS was 85–95% in L2 cells and 75–85% in 11Lu cells. Exposure to 25–250 μM ZnCl₂ for 2 h diminished protein synthesis as determined by radiolabeled methionine incorporation, with half-maximum inhibition (EC₅₀) from 40–160 μM ZnCl₂. To attain similar EC₅₀ values in BSO-pretreated cells, only about half the zinc concentrations were required as compared to cells without pretreatment. The decrease of cGS was accompanied by an increased ratio of oxidized : reduced glutathione that was more pronounced in cells with low glutathione content.     

Monitoring metals in the population living in the vicinity of a hazardous waste incinerator

This study is a part of a monitoring program for the determination of metals in various human tissues of the population living in the vicinity of a new hazardous waste incinerator (HWI) in Constantí (Tarragona County, Spain). Concentrations of arsenic (As), beryllium (Be), cadmium (Cd), chromium (Cr), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), tin (Sn), thallium (Tl), and vanadium (V) were determined in brain, bone, kidney, liver, and lung autopsy samples collected in 2003 from 22 individuals who had been living for at least 10 yr in the area under evaluation. Results were compared with the metal levels obtained in a baseline study, which was performed during the construction of the HWI (1996–1998). In the present survey, As, Be, Tl, and V levels were not detected in any of the analyzed tissues, while Cr concentrations were very close to the limit of detection. The highest levels of Cd and Hg were found in kidney (17.46 μg/g and 0.23 μg/g, respectively), those of Mn in liver (1.07 μg/g), and those of Ni, Pb, and Sn in bone (1.16 μg/g, 2.11 μg/g, and 0.34 μg/g, respectively). In comparison to the results of the baseline study, a general reduction of most metal concentrations was observed in the current survey.     

Evaluation of Association between Biomarkers of Lead Exposure in Sardinian Children (Italy)

The aim of this work is to verify whether there are statistically significant correlations between the concentrations of lead in blood, urine, and hair in children. The sample collected in 2007 consists of 163 children of both sexes from 11–14-year-olds, living in three municipalities of Sardinia (Italy). Inductively coupled plasma atomic mass spectrometry has been used in the determination of lead concentration in biological material. For the overall sample, there is a non-significant partial correlation among the three matrices. However, for subjects with blood lead levels ≥5 μg/dL, there is a significant positive partial correlation between the lead levels in blood and hair, but not between blood and urine or between urine and hair. The results suggest that blood is the preferred biomarker to ascertain lead exposure in human populations, whereas hair can be used as a tool screening when an area is exposed to medium or high lead pollution.