Fluoride in drinking water and dental fluorosis

In this study we determined the fluoride content in drinking water and hair of 12-year-old schoolchildren from different Serbian municipalities, i.e. Valjevo, Veliko Gradiste, Kacarevo and Vranjska Banja. The analyses were performed using composite fluoride ion-selective electrode. Average fluoride levels were 0.10, 0.15, 0.79 and 11 ppm in well water, 0.07, 0.10, 0.17 and 0.15 ppm in tap water, 19.3, 21.5, 25.4, and 32.5 ppm in hair samples, in Valjevo, Veliko Gradiste, Kacarevo and Vranjska Banja, respectively. Correlation analysis indicated statistically significant positive relationship between fluoride in wells water and fluoride in hair, for all municipalities: correlation coefficients were 0.54 (p < 0.05), 0.89, 0.97 and 0.99 (p < 0.001), in Vranjska Banja, Valjevo, Veliko Gradiste, and Kacarevo, respectively. Positive correlation was obtained also between fluoride in tap water and hair samples in all regions under the study, with statistical significance only in Valjevo municipality, p < 0.05. Dental examination of schoolchildren confirmed dental fluorosis only in the region of Vranjska Banja. Moreover, in endemic fluorotic region of Vranjska Banja, positive and statistically significant correlations were confirmed between fluoride in well water and dental fluorosis level (r = 0.61; p < 0.01) and additionally between fluoride in hair and dental fluorosis level (0.62; p < 0.01). The primary findings from this study have shown that fluoride content in hair is highly correlated with fluoride content in drinking water and dental fluorosis level, indicating that hair may be regarded as biomaterial of high informative potential in evaluating prolonged exposure to fluorides and to individuate children at risk of fluorosis regardless of the phase of teeth eruption.     

Antaxia-telangiectasia mutated gene polymorphisms and susceptibility to chromosomal damage among polycyclic aromatic hydrocarbons exposed workers

The aim was to explore the relationship between the ataxia-telangiectasia mutated (ATM) gene polymorphisms and susceptibility to cytokinesis-block micronucleus among workers exposed to polycyclic aromatic hydrocarbons (PAH). Blood and urine samples of 140 PAH-exposed workers and 66 non-PAH-exposed workers were collected. Seven tagging single nucleotide polymorphisms in ATM gene were selected by pariwise r² method and minor allele frequency cutoff of 0.05 from Chinese genotype data in HapMap project. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to analyze the polymorphisms of ATM rs600931, rs652311, rs227060, rs227292, rs624366, rs189037 and rs228589. The results showed that ATM rs600931 AG and AG+AA genotypes exhibited significantly higher cytokinesis-block micronucleus (CBMN) frequency (11.14 ± 6.91‰ and 10.57 ± 6.82‰) than did the GG genotype (7.66 ± 5.69‰, P = 0.015 and 0.038, respectively). The subjects with rs189037 GA and GA+AA genotypes exhibited significantly higher CBMN frequency (10.99 ± 6.90‰ and 10.51 ± 6.76‰) than that of the GG genotype (7.72 ± 5.82‰, P = 0.018 and 0.035, respectively). The PAH-exposed workers with rs624366 GC and GC+CC genotypes exhibited significantly higher CBMN frequency (11.34 ± 6.74‰ and 10.73 ± 6.62‰) than did the GG genotype (7.61 ± 6.07‰, P = 0.001 and 0.003, respectively). rs227092 GT genotype exhibited significantly higher CBMN frequency (10.78 ± 6.60‰) than did the GG genotype (7.91 ± 6.30‰, P = 0.025) among the PAH-exposed workers. The haplotype pairs GGGGTGC/AAACATT exhibited significantly higher CBMN frequency (12.05 ± 7.40‰) than did the GGGGTGC/GGGGTGC (7.51 ± 6.19‰, P = 0.007) among the PAH-exposed group. In conclusion, it is suggested that the polymorphisms of ATM were associated with the CBMN frequencies among PAH-exposed workers.     

Dietary exposure and biomarkers of arsenic in consumers of fish and shellfish from France

Seafood, especially fish, is considered as a major dietary source of arsenic (As). Seafood consumption is recommended for nutritional properties but contaminant exposure should be considered. The objectives were to assess As intake of frequent French seafood consumers and exposure via biomarkers. Consumptions of 996 high consumers (18 and over) of 4 coastal areas were assessed using a validated food frequency questionnaire. Seafood samples were collected according to a total diet study (TDS) sampling method and analyzed for total As, arsenite (AsIII), arsenate (AsV), arsenobetaïne (AsB), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). The average As dietary exposure is 94.7 ± 67.5 μg/kg bw/week in females and 77.3 ± 54.6 μg/kg bw/week in males (p < 0.001) and the inorganic As dietary exposure is respectively 3.34 ± 2.06 μg/kg bw/week and 3.04 ± 1.86 μg/kg bw/week (p < 0.05).Urine samples were collected from 382 of the subjects. The average urinary As concentration is 94.8 ± 250 μg/g creatinine for females and 59.7 ± 81.8 μg/g for males (p < 0.001). Samples having an As concentration above 75 μg/g creatinine (n = 101) were analyzed for inorganic As (As(III), As(V), MMA(V) and DMA(V)) which was 24.6 ± 27.9 μg/g creatinine for males and 27.1 ±20.6 μg/g for females. Analyses do not show any correlation between dietary exposure and urinary As.These results show that biological results should be interpreted cautiously. Diet recording seems to be the best way to assess dietary As exposure. Seafood is a high source of As exposure but even among high consumers it is not the main source of toxic As. From a public health point of view these results should be interpreted carefully in the absence of international consensus on the health-based guidance value.     

Wetland influences on mercury transport and bioaccumulation in South Carolina

There are three distinct geological provinces in South Carolina (SC), with the blue ridge/piedmont regions in the west/central portion of the state and the coastal plain region in the central/eastern region of the state. Samples were collected along this gradient to identify potential factors contributing to the concentrations of total Hg and total organic carbon (TOC) throughout the state. Overall, there is a gradient across the state, with water column concentrations of total Hg (9-53 pM) and TOC (80-2721 μM) increasing as one moves from the blue ridge/piedmont region to the coastal floodplain region. Total Hg at all sites in SC is significantly (R² = 0.78; P < 0.001) correlated with TOC in the water samples. This correlation explains 78% of the variance in the data and suggests that mercury is associated with organic matter in water bodies throughout the state. A study of mercury speciation within the coastal plain Waccamaw River indicates that concentrations of total Hg range from 10-68 pM and methyl Hg concentrations range from 1-7 pM. Watershed transport efficiencies for coastal floodplain rivers sampled in this study range from 32-72% for total Hg and 78-477% for methyl Hg. The coastal plain sites are located in watersheds that contain a significantly (P < 0.001) higher percentage of wetlands (16.3 ± 5%) than the blue ridge/piedmont region (1.14 ± 1.6%), suggesting that drainage through wetlands contributes to the increased concentrations of TOC and total Hg found in SC coastal plain rivers. There is a significant correlation between mean fish Hg concentrations in largemouth bass from each watershed and percent wetland area in each watershed (R² = 0.66; P = 0.003). This correlation explains 66% of the variance in the data and suggests that increasing percentages of wetland area contribute to fish Hg concentrations in SC coastal plain rivers.     

Association of GSTM1 and GSTT1 polymorphisms with DNA damage in coal-tar workers

DNA damage was evaluated by alkaline comet assay in peripheral blood lymphocytes of 115 coal-tar workers occupationally exposed to polycyclic aromatic hydrocarbons (PAHs) and 105 control subjects. The effect of polymorphisms of glutathione S-transferase (GST) genotypes on the DNA damage was assessed. The mean tail moment (TM) value in the coal-tar workers was significantly higher as compared to the control subjects (12.06 ± 0.55 versus 0.44 ± 0.31; P < 0.05). No significant association (P > 0.05) between the GSTT1 and GSTM1 genotypes and the TM values was found, however highest mean rank TM value was reported in GSTM1 null and GSTT1 null genotypes in both control and exposed subjects. Our results suggest that there is increased DNA damage in coal-tar workers due to PAHs exposure. Polymorphisms in GSTM1 and GSTT1 genes do not show significant effect (P > 0.05) on DNA damage.     

Effect of chromium on the level of IL-12 and IFN-gamma in occupationally exposed workers

Chromium may affect humoral and cellular immunity, acting on T lymphocytes as well as on granulocytes and monocytes cells. Cytokines play an important role in the immune balance. In this study, the level of IL-12 and IFN-γ were evaluated in the sera and PHA/LPS stimulated culture supernatant of human PBMCs of healthy volunteers and occupationally exposed chromium workers. All the workers were highly exposed to chromium having mean of 104.65 ± 77.21 µg/dL (range 23.7-316.8 µg/dL). A suspension of exposed and unexposed human PBMC (0.5 × 10⁶ cells/ml) prepared and cultured in RPMI-1640 supplemented with 10% FCS for 18 h in the presence or absence of LPS (10 ng/ml) which used for stimulation of IL-12 and IFN-γ. The level of IL-12 and IFN-γ were evaluated in the sera samples as well as LPS stimulated and unstimulated culture supernatant of h-PBMCs of chromium exposed workers. In these chromium exposed workers the level of IL-12 was 433.66 ± 197.49 pg/ml and 983.45 ± 330.99 pg/ml in LPS stimulated culture supernatant of normal individuals and highly chromium exposed workers, which was significant (P < 0.05). Although the level of IL-12 was (78.61 ± 61.03 pg/ml to 146.52 ± 46.37 pg/ml) elevated in unstimulated culture supernatant of h-PBMCs of chromium exposed individuals as compared to control, but it was not significant. This observation also suggests that a significant increase in IFN-γ production in LPS stimulated and unstimulated culture supernatant of h-PBMCs of chromium exposed workers as compared to control. However, IFN-γ level have a significant positive correlation between blood chromium level (r = 0.833, t = 6.3872, P 0.05) and exposure time (in years) (r = 0.8916, t = 8.3540, P 0.05) of the occupationally exposed workers.     

Arsenic bioaccessibility in CCA-contaminated soils: Influence of soil properties, arsenic fractionation, and particle-size fraction

Arsenic bioaccessibility in soils near chromated copper arsenate (CCA)-treated structures has recently been reported, and results have shown that soil properties and arsenic fractionation can influence bioaccessibility. Because of the limited data set of published results, additional soil samples and a wider range of soil properties are tested in the present work. The objectives are: (1) to confirm previous results regarding the influence of soil properties on arsenic bioaccessibility in CCA-contaminated soils, (2) to investigate additional soil properties influencing arsenic bioaccessibility, and to identify chemical extractants which can estimate in vitro gastrointestinal (IVG) bioaccessibility, (3) to determine arsenic speciation in the intestinal phase of the IVG method and, (4) to assess the influence of two particle-size fractions on arsenic bioaccessibility. Bioaccessible arsenic in eight soils collected near CCA-treated utility poles was assessed using the IVG method. Five out of the eight soils were selected for a detailed characterization. Moreover, these five soils and two certified reference materials were tested by three different metal oxide extraction methods (citrate dithionite (CD), ammonium oxalate (OX), and hydroxylamine hydrochloride (HH)). Additionally, VMINTEQ was used to determine arsenic speciation in the intestinal phase. Finally, two particle-size fractions (< 250 μm, < 90 μm) were tested to determine their influence on arsenic bioaccessibility. First, arsenic bioaccessibility in the eight study-soils ranged between 17.0 ± 0.4% and 46.9 ± 1.1% (mean value 30.5 ± 3.6%). Using data from 20 CCA-contaminated soil samples, total organic carbon (r = 0.50, p < 0.05), clay content (r = − 0.57, p < 0.01), sand content (r = 0.48, p < 0.05), and water-soluble arsenic (r = 0.66, p < 0.01) were correlated with arsenic bioaccessibility. The mean percentage of total arsenic extracted from five selected soils was: HH (71.9 ± 4.1%) > OX (58.0 ± 3.1%) > water-soluble arsenic (2.2 ± 0.5%), while the mean value for arsenic bioaccessibility was 27.3 ± 2.8% (n = 5). Arsenic extracted by HH (r = 0.85, p < 0.01, n = 8) and OX (r = 0.93, p < 0.05, n = 5), showed a strong correlation with arsenic bioaccessibility. Moreover, dissolved arsenic in the intestinal phase was exclusively under the form of arsenate As(V). Finally, arsenic bioaccessibility (in mg/kg) increased when soil particles < 90 μm were used.     

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

Objective

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

Methods

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

Results

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

Conclusion

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

Study on the changes of urinary 8-hydroxydeoxyguanosine levels and burden of heavy metal around e-waste dismantling site

To examine the relations between the burden of blood copper (B-Cu), blood ferrous (B-Fe), and the oxidative stress in people around electronic waste (e-waste) recycling sites, this study measured and analyzed the level of urinary 8-Hydroxy-2′-deoxyguanosine (8-OHDG) of these people. Exposed groups, consisted of female groups (directly exposed group n = 100, indirectly exposed group n = 54) and male groups (directly exposed group n = 98, indirectly exposed group n = 34), were chosen from e-waste recycling sites. Control group (female n = 59, male = 32) was selected from a green plantation. Questionnaire surveys for risk factors were also performed. Results indicated the male directly exposed group (lg8-OHDG nmol/mol creatinine, mean ± SD, 3.55 ± 0.49) showed a lower 8-OHDG level than the male control group (lg8-OHDG nmol/mol creatinine, mean ± SD, 3.89 ± 0.29) (p < 0.01), Meanwhile, an elevated B-Fe in male directly exposed group (lgB-Fe ug/L 3.11 ± 0.25) were observed compared with the male control group (lgB-Fe ug/L 2.83 ± 0.22) (p < 0.01). The levels of urinary 8-OHDG were negatively associated with blood ferrous, as confirmed by linear regression model (unstandardized regression coefficient, beta = −0.215, p < 0.05). The present study suggests that the exposure to e-waste might cause the elevation of B-Fe and result in the changes of urinary 8-OHDG levels.     

Biomonitoring of benzene and 1,3-butadiene exposure and early biological effects in traffic policemen

The objective of this study was to determine benzene and 1,3-butadiene exposure through ambient air and personal air monitoring, as well as through biomarkers of exposure, and to evaluate the potential health risk of exposure through the use of biomarkers of early biological effects in central Bangkok traffic policemen. Ambient air concentrations of benzene and 1,3-butadiene at the roadsides were significantly higher than in police offices used as control sites (p < 0.001). Traffic policemen had a significantly higher exposure to benzene (median 38.62 μg/m³) and 1,3-butadiene (median 3.08 μg/m³) than office policemen (median 6.17 μg/m³ for benzene and 0.37 μg/m³ for 1,3-butadiene) (p < 0.001). Biomarkers of benzene exposure, blood benzene, and urinary metabolite, trans, trans-muconic acid were significantly higher in traffic policemen than office policemen (p < 0.001). No significant difference between traffic and office policemen was found in urinary benzene metabolite, S-phenyl mercapturic acid, or in urinary 1,3-butadiene metabolite, monohydroxy-butenyl mercapturic acid. Biomarkers of early biological effects, 8-hydroxy-2′-deoxyguanosine in leukocytes (8-OHdG), DNA-strand breaks, and DNA-repair capacity, measured as an increase in gamma ray-induced chromosome aberrations were significantly higher in traffic policemen than controls (p < 0.001 for 8-OHdG, p < 0.01 for tail length, p < 0.001 for olive tail moment, p < 0.05 for dicentrics and p < 0.01 for deletions). Multiple regression model including individual exposure, biomarkers of exposure, ages and years of work as independent variables showed that only the levels of individual 1,3-butadiene exposure were significantly associated with 8-OHdG and olive tail moment at p < 0.0001 indicating more influence of 1,3-butadiene on DNA damage. These results indicated that traffic policemen, who are exposed to benzene and 1,3-butadiene at the roadside in central Bangkok, are potentially at a higher risk for development of diseases such as cancer than office policemen.     

A comparison of the isotopic composition of lead in rainwater, surface vegetation and tree bark at the long-term monitoring site, Glensaugh, Scotland, in 2007

The lead concentrations and isotopic ratios (²⁰⁶Pb/²⁰⁷Pb, ²⁰⁸Pb/²⁰⁶Pb, ²⁰⁸Pb/²⁰⁷Pb) of 31 rainwater (September 2006-December 2007) and 11 surface vegetation (moss, lichen, heather) samples (October 2007) from the rural upland catchment of Glensaugh in northeast Scotland and of nine bark samples (October 2007) from trees, predominantly Scots pine, in or near Glensaugh were determined. The mean ²⁰⁶Pb/²⁰⁷Pb ratios for rainwater in 2006 and 2007 were similar to those previously determined for 2000 to 2003 at Glensaugh, yielding an average mean annual value of 1.151 ± 0.005 (± 1 SD) for the period from 2000, when an outright ban on leaded petrol came into force in the UK, to 2007. The mean ²⁰⁶Pb/²⁰⁷Pb ratio (1.146 ± 0.004; n = 7) for surface vegetation near the top (430-450 m) of the catchment was not significantly different (Student's t test) from that of rainwater (1.148 ± 0.017; n = 24) collected over the 12-month period prior to vegetation sampling, but both were significantly different, at the 0.1% (i.e. p < 0.001) and 1% (p < 0.01) level, respectively, from the corresponding mean value (1.134 ± 0.006; n = 9) for the outermost layer of tree bark. When considered in conjunction with similar direct evidence for 2002 and indirect evidence (e.g. grass, atmospheric particulates, dated peat) for recent decades in the Glensaugh area, these findings confirm that the lead isotopic composition of surface vegetation, including that of suitably located moss, reflects that of the atmosphere while that of the outermost layer of Scots pine bark is affected by non-contemporaneous lead. The nature and relative extent of the different contributory sources of lead to the current UK atmosphere in the era of unleaded petrol, however, are presently not well characterised on the basis of lead isotopic measurements.     

Room air temperature affects occupants’ physiology,perceptions and mental alertness

Thermal environment that causes thermal discomfort may affect office work performance. However, the mechanisms through which occupants are affected are not well understood. This study explores the plausible mechanism linking room air temperature and mental alertness through perceptual and physiological responses in the tropics. Ninety-six young adults participated as voluntary subjects in a series of experiment conducted in the simulated office settings. Three room air temperatures, i.e. 20.0, 23.0 and 26.0 °C were selected as the experimental conditions. Both thermal comfort and thermal sensation changed significantly with time under all exposures (P < 0.0001). Longer exposure at 20.0 °C led to cooling sensations due to lower skin temperatures (P < 0.0001) and was perceived as the least comfortable. Nevertheless, this moderate cold exposure induced nervous system activation as demonstrated by the increase of α-Amylase level (P < 0.0001) and the Tsai–partington test (P < 0.0001). A mechanism linking thermal environment, occupants' responses and performance is proposed.     

Habitat structure influences below ground biocontrol services: A comparison between urban gardens and vacant lots

Urban agriculture offers a framework for local self-reliance by provisioning food security, employment opportunities, and other community benefits. However, urban agriculture must rely on the supporting and regulating services of the soil food web. Hence, we quantified belowground biocontrol activity in urban gardens and vacant lots in two post-industrial cities using an in situ insect baiting technique. Due to the differences in habitat structure, we hypothesized that belowground biocontrol services will differ between gardens and vacant lots and the influence of habitat structure would differ with the type of biocontrol organism. Results revealed that biocontrol activity, as assessed by % mortality of baited insects, varied between 51% and 98% with higher activity often recorded in vacant lots than gardens. Major contributions to bait insect mortality were by ants, followed by microbial pathogens and entomopathogenic nematodes, respectively. Ants showed higher (p < 0.0001) % mortality in vacant lots (60% ± 33.4%) than in urban gardens (33.3% ± 22.2%) whereas microbial pathogens exhibited higher (p < 0.0001) mortality in gardens (27.8% ± 15%) than vacant lots (8.3% ± 16.7%). Ants caused higher (p < 0.0001) mortality when larger-mesh size cages were used compared with the smaller-mesh size cages, but mortality by microbial pathogens did not differ with cage type. The high biocontrol activity indicates the resilience of the soil food web in urban ecosystems and the differential effects of habitat structure on biocontrol activity can help guide landscape planning and vegetation management to enhance urban environments and boost local self-reliance.     

Assessment of in-stream phosphorus dynamics in agricultural drainage ditches

The intensive agricultural systems in the Midwestern United States can enrich surface waters with nutrients. Agricultural drainage ditches serve as the first and second order streams throughout much of this region, as well as other highly productive agricultural areas in humid regions throughout the world. This project was conducted to evaluate in-stream processing of soluble P (SP) in agricultural drainage ditches. Soluble P injection studies were conducted at seven sites along three drainage ditches (298 to 4300 ha drainage area), and one site on a third-order stream that receives the discharge from the agricultural ditches (19,000 ha drainage area) by increasing the SP concentration in the ditch water by approximately 0.25 mg L^− 1. Sediments collected from smaller watersheds contained greater amounts of Mehlich 3 and exchangeable P (ExP), silt and clay size particles, and organic matter. Phosphorus uptake lengths (S_net) ranged from 40 to 1900 m, and SP uptake rates (U) ranged from 0.4 to 52 mg m^− 2 h^− 1. Phosphorus S_net was correlated with ditch geomorphological (i.e. width) and sediment properties (i.e. organic matter, ExP, and equilibrium P concentration; r² = 1.00, P < 0.001), indirect drainage in the watershed (r² = 0.92, P < 0.001), and the amount of small grains, forest, urban area, alfalfa and corn (r² = 1.00, P < 0.0001). Agricultural drainage ditches actively process nutrients and could potentially be managed to optimize this processing to minimize SP export from these landscapes.     

Exposure to pastures fertilised with sewage sludge disrupts bone tissue homeostasis in sheep

The femurs of male and female sheep (Ovis aries), aged 18 months, bred on pastures fertilized twice annually with sewage sludge (2.25 tonnes dry matter/ha; Treated; T)) or on pastures treated with inorganic fertilizer (Control; C) were studied, using peripheral Quantitative Computed Tomography (pQCT) and the three-point bending test. Males were maintained on the respective treatments from conception to weaning and then maintained on control pastures while the females were maintained on the respective treatments until slaughter.T rams exhibited increased total bone mineral density (BMD) at the metaphyseal part of femur (+ 10.5%, p < 0.01) compared with C rams but had a reduced total cross sectional area (CSA, − 11.5%, p < 0.001), trabecular CSA (− 17.1%, p < 0.01) and periosteal circumference (− 5.7%, p < 0.001). In the mid-diaphyseal part, T rams had an increased total BMD (+ 13.8%, p < 0.0001) and stiffness (+ 6.4%, p < 0.01) but reduced total CSA (− 12.1%, p < 0.0001) and marrow cavity (− 25.8%, p < 0.0001), relative to C rams.In ewes although pQCT analysis of neither the metaphyseal nor the mid-diaphyseal part of the female femur bones showed any significant differences with treatment, the biomechanical method revealed a reduction in load at failure (− 17.3%, p < 0.01) and stiffness (− 10.7%, p < 0.05) amongst T ewes. It is concluded that exposure to pollutants present in sewage sludge can perturb bone tissue homeostasis in sheep, but particularly in males.     

Mercury exposure assessment in Iranian women's hair of a port town with respect to fish consumption and amalgam fillings

In this study we aimed to estimate the level of mercury in women's hair and its association with fish consumption and amalgam fillings in an Iranian southern port town (named Mahshahr). A total number of 195 hair samples were collected randomly from women aged 25-45 years free from occupational exposures to mercury. Additional information about these women's age, weight, height, number of pregnancies, level of education, number of amalgam fillings and fish consumption were also gathered. The determination of Hg level in hair samples was carried out by the LECO, AMA 254, Advanced Mercury Analyzer, according to ASTM standard No. D-6722. The average mercury level in these women's hair was 2.95 ± 2.33 µg/g (ranged from 0.07 to 24.46 µg/g). In the next stage, the study participants were divided into four groups with respect to their fish consumption and number of amalgam fillings; A) < 3 amalgam fillings, < 3 times fish consumption per month, B) < 3 amalgam fillings, > 7 times fish consumption per month, C) > 6 amalgam fillings, < 3 times fish consumption per month, and D) > 6 amalgam fillings, > 7 times fish consumption per month. Statistical analysis showed that the Hg level was significantly different in these four groups (P < 0.001). Mercury levels in this sample exceeded the USEPA-recommended 1 μg/g in 76.4% of the studied population. Finally, the multiple linear regression results revealed that frequency of fish consumption and amalgam restorations are the most important routes of Hg exposure. However, the main determinant of Hg exposure was the intake of Hg through fish consumption.     

Effect of cadmium, lead and arsenic on the oviposition, hatching and embryonic survival of Biomphalaria glabrata

Biomphalaria glabrata is a widespread freshwater gastropod mollusc. The easy aquaculture of these organisms allow its use as an accessible tool for contamination bioassays. B. glabrata showed marked metabolic responses when exposed to cadmium, lead and arsenic. Those responses could also affect the reproduction of the snails. Taking into account this hypothesis, B. glabrata were exposed for 96 h (acute laboratory bioassays) to different concentrations of cadmium (0.1, 0.05 and 0 mg/L), lead (0.5, 0.1, 0.05 and 0 mg/L) and arsenic (0.5, 0.1, 0.05 and 0 mg/L). Snails were removed from the aquaria while eggs were left in the same contaminant concentrations. The effect of the assayed toxicants on snail reproduction was registered as the alterations of the total number of laid eggs (TNLE), hatching time and embryonic survival.At 0.10 mg/L cadmium significantly decreased the TNLE (p < 0.05) and no embryos survived. The lowest assayed level (0.05 mg/L) of cadmium, delayed the hatching time twice when it was compared with the control group (p < 0.01).Lead decreased the TNLE at 0.5 mg/L level (p < 0.01). The other assayed doses (0.05 and 0.10 mg/L) also decreased embryonic survival significantly (p < 0.05 and p < 0.01 respectively) and extended twice the time to hatching (p < 0.01). The 0.50 mg/L level killed all embryos.Arsenic at all studied concentrations decreased the TNLE (p < 0.05) while the hatching time was increased by 50%. Embryo survival only decreased at the highest level (0.5 mg/L) of arsenic assayed.In summary, the acute exposure (96 h) to cadmium lead and arsenic, altered the reproduction of B. glabrata, modifying the TNLE, hatching time and embryonic survival.     

Levels of chlorinated pesticides and polychlorinated biphenyls in Norwegian breast milk (2002-2006), and factors that may predict the level of contamination

In the present study, polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were determined in 423 breast milk samples from women living in Norway. Various predictors for the contaminant levels were also investigated. The samples were collected in six counties, representing South, Central and North Norway in 2002-2006. Initial results showed significantly lower levels of OCPs in breast milk from ethnic Norwegians (N = 377) compared to ethnic non-Norwegians (N = 46). Median concentrations (range) of PCBs, p,p′-DDE, HCB, β-HCH and oxychlordane in breast milk of the Norwegian women, all parities included, were 103 (34-450), 41 (5.4-492), 11 (3.6-24), 4.7 (0.9-37) and 2.8 (0.5-16) ng/g lipid weight, respectively. Results indicated that sum of 18 PCBs, p,p′-DDE and β-HCH are good predictors for monitoring of PCB, DDT and HCH levels in Norwegian breast milk. Multivariable linear regression analyses showed that age was strongly associated with increasing OC levels (P < 0.001), whereas parity was associated with decreasing OC levels (P < 0.001). Smoking was associated with higher levels of PCBs, p,p′-DDE and β-HCH. The models explained from 17 to 35% of the variance. Median levels of OCs in the present Norwegian primparaes seemed to be 29-62% lower than corresponding results found in a Norwegian study from 2000-2002.     

Whole blood mercury and selenium concentrations in a selected Austrian population: does gender matter?

Background

Data on mercury exposure of the Austrian population were inadequate. This study was performed to determine the causal factors underlying mercury exposure and selenium concentrations, and to estimate the gender-related health impacts.

Methodology

Venous blood samples of 78 women and 81 men were drawn at the Austrian Red Cross, Vienna. Mercury contents in acid-digested whole blood samples were measured after amalgam enrichment by CV-AAS, and selenium by AAS (heated quartz-cell) after hydrid formation.

Results

The average total mercury blood content of Austrians was low (2.38 ± 1.55 μgL^− 1; N = 152). Mercury and selenium concentrations were not different between the genders (P > 0.05) but we observed discrepancies regarding the causal factors. Mercury levels in men were influenced not only by fish consumption but also by age, education level, and amalgam fillings, whereas in women, only the diet (fish/seafood, red wine consumption) determined blood mercury (P < 0.05). Moreover, only the males indicated a depressive effect of dental amalgam on hematocrit (P < 0.05). Regarding selenium, age and alcohol consumption led to lower concentrations in men, whereas a high-level education had the opposite effect; no determinant was found for women. For the whole study group, a significant effect of chronic disease on selenium levels could be detected (P < 0.05). 18% of women and 13% of men showed marginal selenium deficiency (blood selenium < 65 μgL^− 1). Selenium and mercury concentrations were not correlated.

Conclusions

Our results indicate the need to evaluate and integrate gender-related findings in metal toxicology and trace element research, because different causal factors require different preventive measures to reduce mercury exposure and the risk of low selenium concentrations. Future research is needed on the gender- and age-related differences in fish/seafood consumption habits, the modifications of mercury toxicokinetics through sex hormones, the selenium supply in Austria, and the clinical relevance of a low selenium status.     

Temporal analysis of net fluvial methylmercury loading in a dystrophic and a clear water lake

The concentration of methylmercury (MeHg) in aquatic ecosystems is the net result of the highly dynamic abiotic and biotic processes of mercury methylation and demethylation. In this study, we conduct an examination of the net fluvial loading of methylmercury (MeHg_Net = MeHg_Watershed − MeHg_{Lake outflow}) across a 3 year time frame in both a dystrophic lake and an oligotrophic lake. A significant portion of MeHg_Net variance in both lakes could be attributed to a seasonal pattern (11.4%, p = 0.009; oligotrophic, and 27.0%, p < 0.0001; dystrophic) which in both cases, was most correlated with air temperature. The dystrophic lake appeared to be a net source of methylmercury (MeHg_Net = − 1.9 ± 0.3 mg MeHg d^− 1) while the oligotrophic lake appeared to be a net sink (MeHg_Net = 0.4 ± 0.2 mg MeHg d^− 1), indicating that there was net methylation in the dystrophic lake and net demethylation in the oligotrophic lake. Higher MeHg loading to the lakes occurred during the summer and between seasons there was a difference in MeHg_Net of 1.1 ±0.3 mg MeHg d^− 1 and 3.1 ± 0.6 mg MeHg d^− 1. Seasonal patterns of MeHg_Net in the oligotrophic lake lagged behind the dystrophic lake by 39 days. The short term variation in MeHg_Net was dominated by precipitation (t = 2.73, p = 0.008; dystrophic, t = 2.53, p = 0.017; oligotrophic).