Density and proximity of oil and gas wells and concentrations of trace elements in urine, hair, nails and tap water samples from pregnant individuals living in Northeastern British Columbia.

BACKGROUND: Oil and gas exploitation can release several contaminants in the environment, including trace elements, with potentially deleterious effects on exposed pregnant individuals and their developing fetus. Currently, there is limited data on pregnant individuals' exposure to contaminants associated with oil and gas activity. OBJECTIVES: We aimed to 1)measure concentrations of trace elements in biological and tap water samples collected from pregnant individuals participating in the EXPERIVA study; 2)compare with reference populations and health-based guidance values; 3)assess correlations across matrices; and 4)evaluate associations with the density/proximity of oil and gas wells. METHODS: We collected tap water, hair, nails, and repeated urine samples from 85pregnant individuals, and measured concentrations of 21trace elements. We calculated oil and gas well density/proximity (Inverse Distance Weighting [IDW]) for 4buffer sizes (2.5 km, 5 km, 10 km, no buffer). We performed Spearman's rank correlation analyses to assess the correlations across elements and matrices. We used multiple linear regression models to evaluate the associations between IDWs and concentrations. RESULTS: Some study participants had urinary trace element concentrations exceeding the 95th percentile of reference values; 75% of participants for V, 29% for Co, 22% for Ba, and 20% for Mn. For a given trace element, correlation coefficients ranged from -0.23 to 0.65 across matrices; correlations with tap water concentrations were strongest for hair, followed by nails, and urine. Positive (e.g., Cu, Cr, Sr, U, Ga, Ba, Al, Cd) and negative (e.g., Fe) associations were observed between IDW metrics and the concentrations of certain trace elements in water, hair, and nails. SIGNIFICANCE: Our results suggest that pregnant individuals living in an area of oil and gas activity may be more exposed to certain trace elements (e.g., Mn, Sr, Co, Ba) than the general population. Association with density/proximity of wells remains unclear.

The Influence of Smoking and Occupational Risk Factors on DNA Methylation in the AHRR and F2RL3 Genes.

BACKGROUND: AHRR and F2RL3 hypomethylation has been associated with lung cancer. In this study, we investigated the cross-sectional association between smoking and occupational exposures, and AHRR and F2RL3 methylation. METHODS: A case-control study was nested in CARTaGENE to examine the association between AHRR and F2RL3 methylation and lung cancer risk (200 cases; 400 controls). A secondary analysis was conducted using the data collected from this nested study; namely, baseline information on participants' smoking behavior and longest-held job was obtained. A cumulative smoking index summarized information on the number of cigarettes smoked, duration of smoking, and time since cessation. Exposure to 13 occupational agents was estimated using the Canadian Job Exposure Matrix. In baseline blood samples, methylation ratios of 40 CpG sites in the AHRR and F2RL3 genes were measured using Sequenom EpiTYPER. Separate least squares regression models were used to estimate the associations between smoking and occupational exposures, and average AHRR and F2RL3 methylation levels, while adjusting for confounders identified from directed acyclic graphs. RESULTS: In both genes, smoking was associated with lower average methylation levels. Occupational exposure to aromatic amines, cadmium, and formaldehyde were associated with lower AHRR methylation while, only benzene was associated with F2RL3 hypomethylation; these associations were stronger among ever smokers. CONCLUSIONS: Our findings support that smoking and occupational exposures to some agents are associated with AHRR and F2RL3 hypomethylation. IMPACT: Our results inform on mechanisms underlying environmental exposures in lung cancer etiology; future studies should prioritize studying joint exposures.

Assessing gestational exposure to trace elements in an area of unconventional oil and gas activity: comparison with reference populations and evaluation of variability.

BACKGROUND: Located in Northeastern British Columbia, the Montney formation is an important area of unconventional oil and gas exploitation, which can release contaminants like trace elements. Gestational exposure to these contaminants may lead to deleterious developmental effects. OBJECTIVES: Our study aimed to (1) assess gestational exposure to trace elements in women living in this region through repeated urinary measurements; (2) compare urinary concentrations to those from North American reference populations; (3) compare urinary concentrations between Indigenous and non-Indigenous participants; and (4) evaluate inter- and intra-individual variability in urinary levels. METHODS: Eighty-five pregnant women participating in the Exposures in the Peace River Valley (EXPERIVA) study provided daily spot urine samples over 7 consecutive days. Samples were analyzed for 20 trace elements using inductively-coupled mass spectrometry (ICP-MS). Descriptive statistics were calculated, and inter- and intra-individual variability in urinary levels was evaluated through intraclass correlation coefficient (ICC) calculation for each trace element. RESULTS: When compared with those from North American reference populations, median urinary levels were higher in our population for barium (~2 times), cobalt (~3 times) and strontium (~2 times). The 95th percentile of reference populations was exceeded at least 1 time by a substantial percentage of participants during the sampling week for barium (58%), cobalt (73%), copper (29%), manganese (28%), selenium (38%), strontium (60%) and vanadium (100%). We observed higher urinary manganese concentrations in self-identified Indigenous participants (median: 0.19 µg/g creatinine) compared to non-Indigenous participants (median: 0.15 µg/g of creatinine). ICCs varied from 0.288 to 0.722, indicating poor to moderate reliability depending on the trace element. SIGNIFICANCE: Our results suggest that pregnant women living in this region may be more exposed to certain trace elements (barium, cobalt, copper, manganese, selenium, strontium, and vanadium), and that one urine spot sample could be insufficient to adequately characterize participants' exposure to certain trace elements. IMPACT STATEMENT: Unconventional oil and gas (UOG) is an important industry in the Peace River Valley region (Northeastern British Columbia, Canada). Information on the impacts of this industry is limited, but recent literature emphasizes the risk of environmental contamination. The results presented in this paper highlight that pregnant women living near UOG wells in Northeastern British Columbia may be more exposed to some trace elements known to be related to this industry compared to reference populations. Furthermore, our results based on repeated urinary measurements show that one urine sample may be insufficient to adequately reflect long-term exposure to certain trace elements.

Proximity and density of unconventional natural gas wells and mental illness and substance use among pregnant individuals: An exploratory study in Canada.

BACKGROUND: Hydraulic fracturing (fracking) is a method used to extract unconventional natural gas (UNG). Living near UNG operations has been associated with various health outcomes, but few have explored the association between UNG and mental health and substance use. Our objective was to evaluate the association between metrics of residential UNG well density/proximity and mental illness and substance use among pregnant individuals in Northeastern British Columbia, Canada. METHODS: Individuals who gave birth at the Fort St John hospital between December 30, 2006 and December 29, 2016 (n = 6278) were included in the study. Exposure was determined using inverse distance weighting (IDW) to calculate the density and proximity of UNG wells to the postal code centroid ofindividual's residential address at delivery. Four exposure metrics, categorized by quartiles, were calculated based on 50, 10, 5 and 2.5 km buffer zones around each postal code centroid. Logistic regression was used to separately evaluate associations between IDW quartiles of each metric and diagnosis of depression and anxiety prior to or during pregnancy, and self-reported substance use during pregnancy, controlling for relevant and available confounders. RESULTS: The second and third quartile (Q) of the 10 km IDW were associated with greater odds of depression (Q2: adjusted (aOR) 1.30, 95% (confidence interval) CI 1.03-1.64; Q3: aOR 1.35, 95% CI 1.07-1.70) compared to the first quartile, but not the fourth. Using the 5 km IDW, we observed a suggestive positive association with depression in the second and third quartile (aOR Q2: 1.21, 95% CI 0.96-1.53; aOR Q3: 1.24, 95% CI 0.98-1.57) compared to the first quartile. No statistically significant association was observed using the 2.5 km IDW exposure metric. CONCLUSION: We observed some evidence of greater odds of mental illness prior to or during pregnancy, and substance use during pregnancy in pregnant individuals living in postal codes with increased UNG well density/proximity, although associations were not observed in smaller buffer zones. This study adds to the growing literature on the adverse health outcomes surrounding living in proximity to UNG operations.

Observational Surveillance Approach to Detect Novel Work-Related Diseases and Hazards: An Application to a Belgian Occupational Health and Safety Database.

OBJECTIVES: Rapid changes in working conditions give rise to new occupational health risks. We applied the Spectrosome approach, a network-based analysis, to investigate associations between disease and multiple occupational exposures. METHODS: We investigated work and health's associations in a specific sector: the agricultural sector and for a specific and frequent health complaint: sore throat; using PRECUBE dataset of the Belgian Occupational Health and Safety, containing 381.615 occupational health observations. We compared the results of the spectrosome with classic frequency analyses. RESULTS: Spectrosome approach reports more significant signals of multiple associations of agents compare to the frequency analysis. CONCLUSION: This difference justifies the usefulness of taking into account the multiplicity of causes leading to a health event, which is a clear asset of the Spectrosome method.

The spectrosome of occupational health problems.

Given the increased prevalence of cancer, respiratory diseases, and reproductive disorders, for which multifactorial origins are strongly suspected, the impact of the environment on the population represents a substantial public health challenge. Surveillance systems have become an essential public health decision-making tool. Networks have been constructed to facilitate the development of analyses of the multifactorial aspects of the relationships between occupational contexts and health. The aim of this study is to develop and present an approach for the optimal exploitation of observational databases to describe and improve the understanding of the (occupational) environment-health relationships, taking into account key multifactorial aspects. We have developed a spectral analysis (SA) approach that takes into account both the multi-exposure and dynamic natures of occupational health problems (OHPs) and related associations. The main results of this paper are to present the construction method of the "spectrum" and "spectrosome" of OHPs (range and structured list of occupational exposures) and describe the information contained therein with an illustrative example. The approach is illustrated using the case of non-Hodgkin lymphoma (NHL) from the French National Occupational Diseases Surveillance and Prevention Network database as a working example of an occupational disease. We found that the NHL spectrum includes 40 sets of occupational exposures characterized by important multi-exposures, especially solvent combinations or pesticide combinations, but also specific exposures such as polycyclic aromatic hydrocarbons, formaldehyde and ionizing radiation. These findings may be useful for surveillance and the assessment of occupational exposure related to health risks.