Substantial decline of polychlorinated biphenyls serum levels 10 years after public health interventions in a population living near a contaminated site in Northern Italy

IntroductionPolychlorinated biphenyls (PCBs) are persistent pollutants classified among endocrine disruptors and human carcinogens. In an urban area in Northern Italy (Brescia), a chemical factory producing PCBs from 1938 to 1984 caused soil and food pollution. Since the discovering of the environmental pollution in the area in 2001, various public health interventions have been implemented to avoid human contamination.MethodsTwo independent surveys were carried out in 2003 and 2013 using the same study design and methods. A random sample of the adult general population living in four areas of the town with different soil contamination level was enrolled in both surveys. Investigation included serum levels of 24 PCB congeners and of other common clinical-chemical parameters and questions about residential and occupational history as well as current and past diet and consumption of locally produced food. 537 subjects were tested in the 2003 and 488 in the 2013 survey.ResultsTotal PCB serum levels showed a strong correlation with age (Spearman r = 0.71 in 2003 and r = 0.80 in 2013), but not with gender. Consumers of food produced in the most polluted area had higher total PCB serum levels (median 15.6 and 4.7 ng/ml in 2003 and 2013, respectively) than non-consumers (4.1 and 2.3 ng/ml) and consumers of food produced in non-polluted areas (6.5 and 1.9 ng/ml), with increasing trend of PCB serum levels with cumulative local food intake. PCB serum levels from 2003 to 2013 survey declined by around half in all age groups, especially among the youngest people. The total PCB reduction was found to be due to a combination of a birth cohort effect (− 41% every 10 years) and survey period effect (− 18% in 2013 versus 2003), with medium chlorinated CB congeners showing the most relevant reduction (− 30%) between the two surveys. High chlorinated CBs were more strongly associated with birth cohort (− 46% every 10 years): in the 2013 survey they represented 58% of total PCBs in 60–79 years old while they were 37% among the under 40s with a median value 20 times higher in the oldest than in the youngest (3.1 versus 0.16 ng/ml).ConclusionsPCBs serum levels declined from the 2003 to 2013 survey though they are still high in the elderly mainly because of past intake of locally produced contaminated food. Present findings suggest that PCBs food chain contamination and human absorption have been interrupted successfully in the area since discovery of the pollution in 2001.     

Mechanistic polychlorinated biphenyl exposure modeling of mothers in the Canadian Arctic: the challenge of reliably establishing dietary composition

BackgroundTraditional food (TF) consumption represents the main route of persistent organic pollutant (POP) exposure for indigenous Arctic Canadians. Ongoing dietary transitions away from TFs and toward imported foods (IFs) may contribute to decreasing POP exposures observed in these groups.MethodsTo explore this issue, we combined the global fate and transport model GloboPOP and the human food chain bioaccumulation model ACC-Human Arctic to simulate polychlorinated biphenyl (PCB) exposure in two indigenous Arctic Canadian communities from the Inuvik region, Northwest Territories and Baffin region, Nunavut. Using dietary survey information from initial (1996–98) and follow-up (2005–07) biomonitoring campaigns in Inuvik and Baffin, we simulated PCB exposures (PCB-118, -138, -153, and -180) for each individual study participant and also whole study populations.ResultsTF intake rates, particularly of marine mammals (MMs), were the most important predictors of modeled PCB exposure, while TF consumption did not associate consistently with measured PCB exposures. Further, reported mean TF intake increased from baseline to follow-up in both Inuvik (from 8 to 183 g d^− 1) and Baffin (from 60 to 134 g d^− 1), opposing both the expected dietary transition direction and the observed decrease in human PCB exposures in these communities (ΣPCB Inuvik: from 43 to 29 ng g lipid^− 1, ΣPCB Baffin: from 213 to 82 ng g lipid^− 1). However dietary questionnaire data are frequently subject to numerous biases (e.g., recall, recency, confirmation), and thus casts doubt on the usefulness of these data.ConclusionsUltimately, our model's capability to reproduce historic PCB exposure data in these two groups was highly sensitive to TF intake, further underscoring the importance of accurate TF consumption reporting, and clarification of the role of dietary transitions in future POP biomonitoring of indigenous Arctic populations.     

Exposure to multiple sources of polycyclic aromatic hydrocarbons and breast cancer incidence

BackgroundDespite studies having consistently linked exposure to single-source polycyclic aromatic hydrocarbons (PAHs) to breast cancer, it is unclear whether single sources or specific groups of PAH sources should be targeted for breast cancer risk reduction.ObjectivesThis study considers the impact on breast cancer incidence from multiple PAH exposure sources in a single model, which better reflects exposure to these complex mixtures.MethodsIn a population-based case-control study conducted on Long Island, New York (N = 1508 breast cancer cases/1556 controls), a Bayesian hierarchical regression approach was used to estimate adjusted posterior means and credible intervals (CrI) for the adjusted odds ratios (ORs) for PAH exposure sources, considered singly and as groups: active smoking; residential environmental tobacco smoke (ETS); indoor and outdoor air pollution; and grilled/smoked meat intake.ResultsMost women were exposed to PAHs from multiple sources, and the most common included active/passive smoking and grilled/smoked food intake. In multiple-PAH source models, breast cancer incidence was associated with residential ETS from a spouse (OR = 1.20, 95%CrI = 1.03, 1.40) and synthetic firelog burning (OR = 1.29, 95%CrI = 1.06, 1.57); these estimates are similar, but slightly attenuated, to those from single-source models. Additionally when we considered PAH exposure groups, the most pronounced significant associations included total indoor sources (active smoking, ETS from spouse, grilled/smoked meat intake, stove/fireplace use, OR = 1.45, 95%CrI = 1.02, 2.04).ConclusionsGroups of PAH sources, particularly indoor sources, were associated with a 30–50% increase in breast cancer incidence. PAH exposure is ubiquitous and a potentially modifiable breast cancer risk factor.     

Novel exposure biomarkers of N,N-diethyl-m-toluamide (DEET): Data from the 2007–2010 National Health and Nutrition Examination Survey

BackgroundN,N-diethyl-m-toluamide (DEET) is a widely used insect repellent in the United States.ObjectivesTo assess exposure to DEET in a representative sample of persons 6 years and older in the U.S. general population from the 2007–2010 National Health and Nutrition Examination Survey.MethodsWe analyzed 5348 urine samples by using online solid-phase extraction coupled to isotope dilution-high-performance liquid chromatography-tandem mass spectrometry. We used regression models to examine associations of various demographic parameters with urinary concentrations of DEET biomarkers.ResultsWe detected DEET in ~ 3% of samples and at concentration ranges (> 0.08 μg/L–45.1 μg/L) much lower than those of 3-(diethylcarbamoyl)benzoic acid (DCBA) (> 0.48 μg/L–30,400 μg/L) and N,N-diethyl-3-hydroxymethylbenzamide (DHMB) (> 0.09 μg/L–332 μg/L). DCBA was the most frequently detected metabolite (~ 84%). Regardless of survey cycle and the person's race/ethnicity or income, adjusted geometric mean concentrations of DCBA were higher in May–Sep than in Oct–Apr. Furthermore, non-Hispanic whites in the warm season were more likely than in the colder months [adjusted odds ratio (OR) = 10.83; 95% confidence interval (CI), 3.28–35.79] and more likely than non-Hispanic blacks (OR = 3.45; 95% CI, 1.51–7.87) to have DCBA concentrations above the 95th percentile.ConclusionsThe general U.S. population, including school-age children, is exposed to DEET. However, reliance on DEET as the sole urinary biomarker would likely underestimate the prevalence of exposure. Instead, oxidative metabolites of DEET are the most adequate exposure biomarkers. Differences by season of the year based on demographic variables including race/ethnicity likely reflect different lifestyle uses of DEET-containing products.     

Male specific association between xenoestrogen levels in placenta and birthweight

BackgroundFetal exposure to endocrine disrupting chemicals may increase the risk for adverse health effects at birth or later in life.ObjectivesThe objective of this study is to analyze the combined effect of xenoestrogens on reproductive and perinatal growth outcomes (child birthweight, early rapid growth and body mass index (BMI) at 14 months) using the biomarker total effective xenoestrogen burden (TEXB).Methods490 placentas were randomly collected in the Spanish prospective birth cohort Environment and Childhood (INMA) project. TEXB was used to assess the estrogenicity of placental samples in two fractions: that largely attributable to environmental organohalogenated xenoestrogens (TEXB-alpha), and that mostly due to endogenous estrogens (TEXB-beta), both expressed in estrogen equivalent units (Eeq) per gram of tissue. Linear or logistic regression models were performed adjusting for cohort and confounders. Sex interactions were investigated.ResultsThe median TEXB-alpha level was 0.76 pM Eeq/g (interquartile range (iqr): 1.14). In multivariate models, higher TEXB-alpha levels (third tertile, > 1.22 pM Eeq/g; iqr: 1.73) were associated with increased birthweight in boys but not in girls (β = 148.2 g, 95% CI: 14.01, 282.53, p_int = 0.057). Additionally, higher TEXB-alpha values in boys were related with a lower risk of early rapid growth (OR = 0.37; 95% CI: 0.15, 0.88) and with a non significant association with larger BMI z-scores at 14 months of age (β = 0.29; 95% CI: − 0.11, 0.69).ConclusionsThese findings suggest that prenatal exposure to xenoestrogens may increase birthweight in boys, which might have an impact on child obesity and other later health outcomes.     

Air pollution exposure and telomere length in highly exposed subjects in Beijing,China: A repeated-measure study

BackgroundAmbient particulate matter (PM) exposure has been associated with short- and long-term effects on cardiovascular disease (CVD). Telomere length (TL) is a biomarker of CVD risk that is modified by inflammation and oxidative stress, two key pathways for PM effects. Whether PM exposure modifies TL is largely unexplored.ObjectivesTo investigate effects of PM on blood TL in a highly-exposed population.MethodsWe measured blood TL in 120 blood samples from truck drivers and 120 blood samples from office workers in Beijing, China. We measured personal PM_2.5 and Elemental Carbon (EC, a tracer of traffic particles) using light-weight monitors. Ambient PM₁₀ was obtained from local monitoring stations. We used covariate-adjusted regression models to estimate percent changes in TL per an interquartile-range increase in exposure.ResultsCovariate-adjusted TL was higher in drivers (mean = 0.87, 95%CI: 0.74; 1.03) than in office workers (mean = 0.79, 95%CI: 0.67; 0.93; p = 0.001). In all participants combined, TL increased in association with personal PM_2.5 (+ 5.2%, 95%CI: 1.5; 9.1; p = 0.007), personal EC (+ 4.9%, 95%CI: 1.2; 8.8; p = 0.01), and ambient PM₁₀ (+ 7.7%, 95%CI: 3.7; 11.9; p < 0.001) on examination days. In contrast, average ambient PM₁₀ over the 14 days before the examinations was significantly associated with shorter TL (− 9.9%, 95%CI: − 17.6; − 1.5; p = 0.02).ConclusionsShort-term exposure to ambient PM is associated with increased blood TL, consistent with TL roles during acute inflammatory responses. Longer exposures may shorten TL as expected after prolonged pro-oxidant exposures. The observed TL alterations may participate in the biological pathways of short- and long-term PM effects.     

A crossover–crossback prospective study of dibutyl-phthalate exposure from mesalamine medications and semen quality in men with inflammatory bowel disease

BackgroundPhthalates are widely used chemicals with ubiquitous exposure. Dibutyl-phthalate (DBP), a male reproductive toxicant in animals, is understudied in humans. Some mesalamine medications used to treat inflammatory bowel disease (IBD) have DBP in their coating, whereas other mesalamine formulations do not.ObjectivesTaking advantage of differences in mesalamine formulations, we investigated whether high-DBP exposure from mesalamine medications was associated with decreased semen parameters.Methods73 men with IBD taking mesalamine participated in a crossover-crossback prospective study. Men taking non-DBP containing mesalamine at baseline i.e., background exposure, crossed-over for four months to high-DBP mesalamine and then crossed-back for four months to their non-DBP mesalamine (B₁HB₂-arm;Background₁-High-Background₂) and vice versa for men taking high-DBP mesalamine at baseline (H₁BH₂-arm;High₁-Background-High₂). Men provided up to six semen samples (2: baseline, 2: crossover and 2: crossback).ResultsWe estimated crossover, crossback and carryover effects using linear mixed models adjusted for abstinence time, age, season and duration on high-DBP mesalamine at baseline. Semen parameters in B₁HB₂-arm (26 men, 133 samples) decreased after high-DBP mesalamine exposure (crossover versus baseline), especially motility parameters, and continued to decrease further even after crossback to non-DBP mesalamine (crossback versus crossover). The cumulative carryover effect of high-DBP (crossback versus baseline) was a decrease of % total sperm motility by 7.61(CI:− 13.1, − 2.15), % progressive sperm motility by 4.23(CI:− 8.05, − 0.4) and motile sperm count by 26.0% (CI:− 46.2%, 1.7%). However, H₁BH₂-arm (47 men, 199 samples) had no significant change during crossover or crossback.ConclusionsMen newly exposed to high-DBP mesalamine for four months had a cumulative reduction in several semen parameters, primarily sperm motility, that was more pronounced and statistically significant even after exposure ended for four months.     

Number of persistent organic pollutants detected at high concentrations in a general population

BackgroundSurveys of human exposure to environmental chemicals do not integrate the number of compounds detected per person and the concentration of each compound. This leaves untested relevant exposure scenarios, such as whether individuals with low concentrations of some compounds have high concentrations of the other compounds.ObjectiveTo analyze the number of persistent organic pollutants (POPs) detected at high concentrations.MethodsSerum concentrations of 19 POPs were analyzed by gas chromatography with electron-capture detection in a representative sample of the general population of Catalonia, Spain (N = 919).ResultsOver 58% of participants had concentrations in the top quartile of ≥ 1 of the eight most prevalent POPs, and 34% of ≥ 3 POPs. 83% of women 60 to 74 years old had concentrations of ≥ 3 POPs in the top quartile; 56% of women 60 to 74 years had p,p′-DDE, HCB and β-HCH all in their respective top quartiles, and 48% had concentrations of ≥ 6 POPs in the top quartile. Over 30% of subjects had concentrations in the top decile of 1 to 5 of the eight most prevalent POPs. Half of the population had levels of 1 to 5 POPs > 500 ng/g. Less than 4% had all eight POPs in the lowest quartile.ConclusionsMore than half of the study population had concentrations in the top quartile of ≥ 1 POPs. Significant subgroups of the population accumulate POP mixtures at high concentrations. POP concentrations appear low in most of the population only when each individual compound is looked at separately.     

Can starling eggs be useful as a biomonitoring tool to study organohalogenated contaminants on a worldwide scale?

Large-scale international monitoring studies are important to assess emission patterns and environmental distributions of organohalogenated contaminants (OHCs) on a worldwide scale. In this study, the presence of OHCs was investigated on three continents (Europe, North America and Australasia), using eggs of starlings (Sturnus vulgaris and Sturnus unicolor) to assess their suitability for large-scale monitoring studies. To the best of our knowledge, this is the first study using bird eggs of the same species as a biomonitor for OHCs on an intercontinental scale. We found significant differences in OHC concentrations of the eggs among sampling locations, except for hexachlorocyclohexanes (HCHs). Mean concentrations of sum polychlorinated biphenyls (PCBs) in eggs ranged from 78 ± 26 ng/g lipid weight (lw) in Australia to 2900 ± 1300 ng/g lw in the United States. The PCB profile was dominated by CB 153 and CB 138 in all locations, except for New Zealand, where the contribution of CB 95, CB 101 and CB 149 was also high. The highest mean sum polybrominated diphenyl ether (PBDE) concentrations were found in Canada (4400 ± 830 ng/g lw), while the lowest mean PBDE concentrations were measured in Spain (3.7 ± 0.1 ng/g lw). The PBDE profile in starling eggs was dominated by BDE 47 and BDE 99 in all countries, but in Belgium, the higher brominated PBDEs had a higher contribution compared to other countries. For the organochlorine pesticides (OCPs), dichlorodiphenyltrichloroethanes (DDTs) ranged from 110 ± 16 ng/g lw in France to 17,000 ± 3400 ng/g lw in New Zealand, while HCHs and hexachlorobenzene were generally in low concentrations in all sampling locations. Chlordanes were remarkably high in eggs from the United States (2500 ± 1300 ng/g lw). The OCP profile in all countries was largely dominated by p,p′-DDE. In general, the worldwide trends we observed in starling eggs were in accordance with the literature on human and environmental OHC data, which suggests that there is potential for using starling eggs as a biomonitoring tool on a large geographical scale.     

Prenatal particulate air pollution and neurodevelopment in urban children: Examining sensitive windows and sex-specific associations

BackgroundBrain growth and structural organization occurs in stages beginning prenatally. Toxicants may impact neurodevelopment differently dependent upon exposure timing and fetal sex.ObjectivesWe implemented innovative methodology to identify sensitive windows for the associations between prenatal particulate matter with diameter ≤ 2.5 μm (PM_2.5) and children's neurodevelopment.MethodsWe assessed 267 full-term urban children's prenatal daily PM_2.5 exposure using a validated satellite-based spatio-temporally resolved prediction model. Outcomes included IQ (WISC-IV), attention (omission errors [OEs], commission errors [CEs], hit reaction time [HRT], and HRT standard error [HRT-SE] on the Conners' CPT-II), and memory (general memory [GM] index and its components — verbal [VEM] and visual [VIM] memory, and attention-concentration [AC] indices on the WRAML-2) assessed at age 6.5 ± 0.98 years. To identify the role of exposure timing, we used distributed lag models to examine associations between weekly prenatal PM_2.5 exposure and neurodevelopment. Sex-specific associations were also examined.ResultsMothers were primarily minorities (60% Hispanic, 25% black); 69% had ≤ 12 years of education. Adjusting for maternal age, education, race, and smoking, we found associations between higher PM_2.5 levels at 31–38 weeks with lower IQ, at 20–26 weeks gestation with increased OEs, at 32–36 weeks with slower HRT, and at 22–40 weeks with increased HRT-SE among boys, while significant associations were found in memory domains in girls (higher PM_2.5 exposure at 18–26 weeks with reduced VIM, at 12–20 weeks with reduced GM).ConclusionsIncreased PM_2.5 exposure in specific prenatal windows may be associated with poorer function across memory and attention domains with variable associations based on sex. Refined determination of time window- and sex-specific associations may enhance insight into underlying mechanisms and identification of vulnerable subgroups.     

Coastal climate is associated with elevated solar irradiance and higher 25(OH)D level

IntroductionThere is evidence that populations living close to the coast have improved health and wellbeing. Coastal environments are linked to promotion of physical activity through provision of safe, opportune, aesthetic and accessible spaces for recreation. Exposure to coastal environments may also reduce stress and induce positive mood. We hypothesised that coastal climate may influence the vitamin D status of residents and thus partly explain benefits to health.Materials and methodsEcological and cross-sectional analyses were designed to elucidate the connection between coastal residence and vitamin D status. We divided residential data, from developed land use areas and the Lower Super Output Areas or Data Zones (Scotland) of the 1958 Birth Cohort participants, into the following coastal bands: < 1 km, 1–5 km, 5–20 km, 20–50 km and over 50 km. In the ecological analysis we used a multiple regression model to describe the relationship between UV_vitd and coastal proximity adjusted for latitude. Subsequently, using the residential information of the participants of the 1958 Birth Cohort we developed a multiple regression model to understand the relationship between serum 25(OH)D (a marker of vitamin D status) and coastal proximity adjusted for several factors related to vitamin D status (e.g. diet, outdoor activity).ResultsWe found that coastal proximity was associated with solar irradiance; on average a 99.6 (96.1–103.3) J/m²/day regression coefficient was recorded for settlements < 1 km from the coast compared with those at > 50 km. This relationship was modified by latitude with settlements at a lower latitude exhibiting a greater effect. Individuals living closer to the coast in England had higher vitamin D levels than those inland, particularly in autumn.ConclusionGeographic location may influence biochemistry and health outcomes due to environmental factors. This can provide benefits in terms of vitamin D status but may also pose a risk due to higher skin cancer risk. We provide further evidence in support of the claim that coastal environments can provide opportunities for health and wellbeing.     

Concentrations of polybrominated diphenyl ethers in matched samples of indoor dust and breast milk in New Zealand

Polybrominated diphenyl ethers (PBDEs) are present in many consumer goods. There is evidence that PBDEs are toxic to humans, particular young children. The purpose of this study was to assess indoor dust as an exposure source for PBDEs. Concentrations of 16 PBDEs were determined in dust samples from 33 households in New Zealand, and in breast milk samples from 33 mothers living in these households. Associations between dust and breast milk PBDE concentrations were assessed, and children's PBDE intake from breast milk and dust estimated. Influences of household and demographic factors on PBDE concentrations in dust were investigated. Indoor dust concentrations ranged from 0.1 ng/g for BDE17 to 2500 ng/g for BDE209. Breast milk concentrations were positively correlated (p < 0.05) with mattress dust concentrations for BDE47, BDE153, BDE154, and BDE209 and with floor dust for BDE47, BDE183, BDE206, and BDE209. The correlation for BDE209 between dust and breast milk is a novel finding. PBDE concentrations in floor dust were lower from households with new carpets. The estimated children's daily intake of PBDEs from dust and breast milk was below U.S. EPA Reference Dose values. The study shows that dust is an important human exposure source for common PBDE formulations in New Zealand.     

Farm residence and reproductive health among boys in rural South Africa

BackgroundFew studies have investigated reproductive health effects of contemporary agricultural pesticides in boys.ObjectivesTo determine the association between pesticide exposure and reproductive health of boys.MethodsWe conducted a cross-sectional study in rural South Africa of boys living on and off farms. The study included a questionnaire (demographics, general and reproductive health, phyto-estrogen intake, residential history, pesticide exposures, exposures during pregnancy); and a physical examination that included sexual maturity development ratings; testicular volume; height, weight, body mass index; and sex hormone concentrations.ResultsAmong the 269 boys recruited into the study, 177 (65.8%) were categorized as farm (high pesticide exposures) and 98 (34.2%) as non-farm residents (lower pesticide exposures). Median ages of the two groups were 11.3 vs 12.0 years, respectively (p < 0.05). After controlling for confounders that included socioeconomic status, farm boys were shorter (regression coefficient (RC) = − 3.42 cm; 95% confidence interval (CI): − 6.38 to − 0.45 cm) and weighed less (RC = − 2.26 kg; CI: − 4.44 to − 0.75 kg). The farm boys also had lower serum lutenizing hormone (RC = − 0.28 IU/L; CI: − 0.48 to − 0.08 IU/L), but higher serum oestradiol (RC = 8.07 pmol/L; CI: 2.34–13.81 pmol/L) and follicle stimulating hormone (RC = 0.63 IU/L; CI: 0.19–1.08 U/L).ConclusionsOur study provides evidence that farm residence is associated with adverse growth and reproductive health of pubertal boys which may be due to environmental exposures to hormonally active contemporary agricultural pesticides.     

Saharan dust,particulate matter and cause-specific mortality: A case–crossover study in Barcelona (Spain)

BackgroundStudies measuring health effects of Saharan dust based on large particulate matter (PM) fraction groups may be masking some effects. Long distant transport reduces the amount of heavier and larger particles in the Saharan air masses increasing the relative contribution of smaller particles that may be more innocuous. This study investigates the association between different PM fractions and daily mortality during Saharan and non-Saharan days in Barcelona, Spain.MethodsWe collected daily PM₁, PM_2.5–1 and PM_10–2.5 fractions, and cause-specific mortality (cardiovascular, respiratory and cerebrovascular) between March 2003 and December 2007. Changes of effects between Saharan and non-Saharan dust days were assessed using a time-stratified case–crossover design.ResultsDuring non-Saharan dust days we found statistically significant (p < 0.05) effects of PM_10–2.5 for cardiovascular (odds ratio for increase of an interquartile range, OR = 1.033, 95% confidence interval: 1.006–1.060) and respiratory mortality (OR = 1.044, 95% CI: 1.001–1.089). During Saharan dust days strongest cardiovascular effects were found for the same fraction (OR = 1.085, 95% CI: 1.017–1.158) with an indication of effect modification (p = 0.111). Effects of PM_2.5–1 during Saharan dust days were about the double than in non-dust days for cardiovascular and respiratory mortality, but these differences were not statistically significant.ConclusionOur results using independent fractions of PMs provide further evidence that the effects of short-term exposure to PM during Saharan dust days are associated with both cardiovascular and respiratory mortality. A better understanding of which of the different PM size fractions brought by Saharan dust is more likely to accelerate adverse effects may help better understand mechanisms of toxicity.     

Uranium in drinking-water: A unique case of guideline value increases and discrepancies between chemical and radiochemical guidelines

BackgroundUranium represents a unique case for an element naturally present in the environment, as its chemical guideline value in drinking water significantly increased from 2 μg/L in 1998 up to 15 μg/L in 2004 and then to 30 μg/L in 2011, to date corresponding to a multiplication factor of 15 within a period of just 13 years.ObjectivesIn this commentary we summarize the evolution of uranium guideline values in drinking-water based on both radiological and chemical aspects, emphasizing the benefit of human studies and their contribution to recent recommendations. We also propose a simpler and better consistency between radiological and chemical values.DiscussionThe current chemical guideline value of 30 μg/L is still designated as provisional because of scientific uncertainties regarding uranium toxicity. During the same period, the radiological guideline for ²³⁸U increased from 4 Bq/L to 10 Bq/L while that for ²³⁴U decreased from 4 Bq/L to 1 Bq/L. These discrepancies are discussed here, and a value of 1 Bq/L for all uranium isotopes is proposed to be more consistent with the current chemical value of 30 μg/L.ConclusionContinuous progress in the domains of toxicology and speciation should enable a better interpretation of the biological effects of uranium in correlation with epidemiological human studies. This will certainly aid future proposals for uranium guideline values.     

Long-term exposure to traffic-related PM10 and decreased heart rate variability: Is the association restricted to subjects taking ACE inhibitors?

BackgroundAlterations in heart rate variability (HRV) are a potential link between exposure to traffic-related air pollution and cardiovascular mortality.ObjectivesWe investigated whether long-term exposure to traffic-related PM₁₀ (TPM₁₀) is associated with HRV in older subjects and/or in participants taking specific cardiovascular treatment or with self-reported heart disease.MethodsWe included 1607 subjects from the general population aged 50 to 72 years. These participants from the SAPALDIA cohort underwent ambulatory 24-hr electrocardiogram monitoring. Associations of average annual exposure to TPM₁₀ over 10 years with HRV parameters from time and frequency domains were estimated using multivariable mixed linear models. Effect estimates are expressed as percent changes in geometric means.ResultsHRV was only associated with TPM₁₀ in participants under ACE inhibitor therapy (N = 94). A 1 μg/m³ increment, approximately equivalent to an interquartile range, in 10 year average TPM₁₀ was associated with decrements of 14.5% (95% confidence interval (CI), − 25.9 to − 1.3) in high frequency (HF) power, of 4.5% (− 8.2 to − 0.5) in the standard deviation of all normal-to-normal RR intervals (SDNN), of 10.6% (− 18.5 to − 1.9) in total power (TP) and an increase of 9.2% (0.8 to 20.2) in the LF/HF power ratio.ConclusionsIn the absence of an overall effect our results suggest that alterations in HRV, a measure of autonomic control of the cardiac rhythm, may not be a central mechanism by which long-term exposure to TPM₁₀ increases cardiovascular mortality. Novel evidence on an effect in persons under ACE inhibitor treatment needs to be confirmed in future studies.     

Selenium exposure in subjects living in areas with high selenium concentrated drinking water: Results of a French integrated exposure assessment survey

BackgroundSelenium is an essential element which can be toxic if ingested in excessive quantities. The main human exposure is food. In addition, intake may be boosted by consumption drinking water containing unusual high selenium concentration.ObjectiveWe measured the individual selenium level of people exposed to selenium concentration in drinking water greater than the maximum recommended limit which is 10 μg/L.MethodsWe carried out a prospective cohort study on 80 adults (40 exposed subjects i.e. living in the involved area and 40 non-exposed ones i.e. living elsewhere) in western France. We used three different approaches: (1) direct measurement of ingested selenium by the duplicate portion method, (2) dietary reconstitution with a food frequency questionnaire (FFQ) and (3) evaluation of the individual selenium status by measuring the selenium content in toenail clippings. Analyses were performed by inductively coupled plasma-mass spectrometry. The association between toenail selenium concentration and area of residence was analyzed using linear regression with repeated measurements.ResultsWe estimated selenium intake from FFQ at 64 ± 14 μg/day for exposed subjects as opposed to 52 ± 14 μg/day for the non-exposed ones. On the basis of 305 duplicate diet samples, average intake was estimated at 64 ± 26 μg/day for exposed subjects. Area of residence (p = 0.0030) and smoking (p = 0.0054) were independently associated with toenail selenium concentration.ConclusionWhatever method used for estimating selenium intake, the selenium level in this studied area with high selenium concentrated drinking water is much lower than in seleniferous areas.     

Dietary benzo(a)pyrene intake during pregnancy and birth weight: Associations modified by vitamin C intakes in the Norwegian Mother and Child Cohort Study (MoBa)

BackgroundMaternal exposure to polycyclic aromatic hydrocarbons (PAH) during pregnancy has been associated with reduced fetal growth. However, the role of diet, the main source of PAH exposure among non-smokers, remains uncertain.ObjectiveTo assess associations between maternal exposure to dietary intake of the genotoxic PAH benzo(a)pyrene [B(a)P] during pregnancy and birth weight, exploring potential effect modification by dietary intakes of vitamins C, E and A, hypothesized to influence PAH metabolism.MethodsThis study included 50,651 women in the Norwegian Mother and Child Cohort Study (MoBa). Dietary B(a)P and nutrient intakes were estimated based on total consumption obtained from a food frequency questionnaire (FFQ) and estimated based on food composition data. Data on infant birth weight were obtained from the Medical Birth Registry of Norway (MBRN). Multivariate regression was used to assess associations between dietary B(a)P and birth weight, evaluating potential interactions with candidate nutrients.ResultsThe multivariate-adjusted coefficient (95%CI) for birth weight associated with maternal energy-adjusted B(a)P intake was − 20.5 g (− 31.1, − 10.0) in women in the third compared with the first tertile of B(a)P intake. Results were similar after excluding smokers. Significant interactions were found between elevated intakes of vitamin C (> 85 mg/day) and dietary B(a)P during pregnancy for birth weight (P < 0.05), but no interactions were found with other vitamins. The multivariate-adjusted coefficients (95%CI) for birth weight in women in the third compared with the first tertile of B(a)P intake were − 44.4 g (− 76.5, − 12.3) in the group with low vitamin C intakes vs. − 17.6 g (− 29.0, − 6.1) in the high vitamin C intake group.ConclusionThe results suggest that higher prenatal exposure to dietary B(a)P may reduce birth weight. Lowering maternal intake of B(a)P and increasing dietary vitamin C intake during pregnancy may help to reduce any adverse effects of B(a)P on birth weight.     

Fibrin clot structure is affected by levels of particulate air pollution exposure in patients with venous thrombosis

BackgroundParticulate air pollution is a risk factor for cardiovascular diseases and thrombosis. Long-term exposure to particulate matter with a diameter < 10 μm (PM₁₀) has been associated with an increased risk of venous thrombosis.ObjectivesThe aim of this study was to investigate whether or not particulate air pollution alters fibrin clot structure and thus modulates thrombosis risk.MethodsWe investigated fibrin polymerization by turbidity (maximum absorbance mOD), clot structure by confocal microscopy (fibre number per μm) and fibrin pore size by permeability (Ks × 10^− 10 cm²) in 103 patients with deep vein thrombosis and 121 healthy controls, for whom levels of air pollution exposure had been recorded. Exposure groups were defined by mean PM₁₀ concentrations over the 730 days before the event.ResultsWe found a higher average number of fibres per clot area in patients than controls, but no difference in Ks or fibre thickness. When the two groups were divided into high or low exposure to PM₁₀, a significantly denser fibrin clot network structure with thicker fibres (higher maximum absorbance, p < 0.05), decreased permeability (lower Ks value, p < 0.05) and higher average fibre numbers per clot area (p < 0.05) was observed in patients in the high exposure group compared to those with low exposure. There were no significant differences in fibrin clot structure between the two exposure levels in healthy subjects.ConclusionsPM₁₀ levels are associated with altered fibrin clot structure in patients with deep vein thrombosis but not in controls, suggesting that air pollution may trigger differences in fibrin clot structure only in patients predisposed to thrombotic disease.