Urinary and hair concentrations of trace metals in pregnant women from Northeastern British Columbia, Canada: a pilot study

Urinary concentrations of mineral elements and their predictors in pregnant women in Jinan, China

BACKGROUND

The essential mineral elements play important roles in proper growth, development and maintenance of physiological homeostasis of an organism. Women are at greater risk of mineral deficiency during pregnancy. However, the predictors of mineral element levels in pregnant women remain unclear. This study was conducted to determine the urinary levels of calcium (Ca), iron (Fe), copper (Cu), manganese (Mn) and selenium (Se) in women during early pregnancy and to explore the predictors of urinary exposure to each mineral element and high co-exposure to mineral element mixture.

METHODS

298 pregnant women in first trimester were recruited when they attended antenatal care in a hospital in Jinan, Shandong Province, China. We collected their spot urine samples and questionnaire data on their sociodemographic characteristics, lifestyle habits, food and dietary supplement intake, and residential environment. The concentrations of Ca, Fe, Cu, Mn and Se in all urine samples were measured. LASSO regression, multiple linear regression and binary logistic regression were used to analyze the predictors affecting mineral element levels.

RESULTS

The geometric means of creatinine-corrected Ca, Fe, Cu, Mn and Se concentrations were 99.37 mg/g, 1.75 µg/g, 8.97 µg/g, 0.16 µg/g and 16.83 µg/g creatinine, respectively. Factors that influenced the concentrations of individual mineral element were as follows: (1) Se and Ca concentrations increased with maternal age; (2) women taking tap water as family drinking water had higher Ca levels and those taking polyunsaturated fatty acids intermittently had higher Cu levels; (3) Fe was adversely related to consumption frequency of barbecued foods; (4) Pregnant women with more frequent consumption of shellfish/shrimp/crab and living near green spaces or parks had higher Mn exposure, and those with higher frequency of meat consumption had lower Mn exposure. In addition, maternal age and the frequency of egg consumption were associated with odds of exposure to a mixture of high Ca, Fe, Cu and Se.

CONCLUSIONS

The pregnant women in this study had comparable concentrations of urinary Cu and Se but lower concentrations of Ca, Fe and Mn compared with those in other areas. Predictors of urinary mineral elements included maternal age (Se and Ca), type of domestic drinking water (Ca), consumption frequency of barbecued food (Fe), polyunsaturated fatty acid use (Cu), the presence of urban green spaces or parks near the home and frequency of meat and shellfish/shrimp/crab intake (Mn). Moreover, maternal age and egg consumption frequency were significant predictors of high-level co-exposure to urinary Ca, Fe, Cu and Se.

Trace elements alone or in mixtures associated with unconventional natural gas exploitation affect rat fetal steroidogenesis and testicular development in vitro

Biomonitoring studies have shown that pregnant women living in regions of unconventional natural gas (UNG) exploitation have higher levels of trace elements. Whether developmental endocrine disruption can be expected at these exposure levels during pregnancy is unclear. In this study, we aimed to test the impact of five trace elements alone or in mixtures using in vitro cell- and tissue-based assays relevant to endocrine disruption and development. Manganese, aluminum, strontium, barium, and cobalt were tested at concentrations including those representatives of human fetal exposure. Using transactivation assays, none of the tested elements nor their mixture altered the human estrogen receptor 1 or androgen receptor genomic signalling. In the rat fetal testis assay, an organ culture system, cobalt (5 μg/l), barium (500 μg/l) and strontium (500 μg/l) significantly increased testosterone secretion. Cobalt and strontium were associated with hyperplasia and/or hypertrophy of fetal Leydig cells. Mixing the five elements at concentrations where none had an effect individually stimulated testosterone secretion by the rat fetal testis paralleled by the significant increase of 3β-hydroxysteroid dehydrogenase protein level in comparison to the vehicle control. The mechanisms involved may be specific to the fetal testis as no effect was observed in the steroidogenic H295R cells. Our data suggest that some trace elements in mixture at concentrations representative of human fetal exposure can impact testis development and function. This study highlights the potential risk posed by UNG operations, especially for the most vulnerable populations, pregnant individuals, and their fetus.

The human health effects of unconventional oil and gas development (UOGD): A scoping review of epidemiologic studies

OBJECTIVE

Unconventional oil and gas development (UOGD, sometimes termed "fracking" or "hydraulic fracturing") is an industrial process to extract methane gas and/or oil deposits. Many chemicals used in UOGD have known adverse human health effects. Canada is a major producer of UOGD-derived gas with wells frequently located in and around rural and Indigenous communities. Our objective was to conduct a scoping review to identify the extent of research evidence assessing UOGD exposure-related health impacts, with an additional focus on Canadian studies.

METHODS

We included English- or French-language peer-reviewed epidemiologic studies (January 2000-December 2022) which measured exposure to UOGD chemicals directly or by proxy, and where health outcomes were plausibly caused by UOGD-related chemical exposure. Results synthesis was descriptive with results ordered by outcome and hierarchy of methodological approach.

SYNTHESIS

We identified 52 studies from nine jurisdictions. Only two were set in Canada. A majority (n = 27) used retrospective cohort and case-control designs. Almost half (n = 24) focused on birth outcomes, with a majority (n = 22) reporting one or more significant adverse associations of UOGD exposure with: low birthweight; small for gestational age; preterm birth; and one or more birth defects. Other studies identified adverse impacts including asthma (n = 7), respiratory (n = 13), cardiovascular (n = 6), childhood acute lymphocytic leukemia (n = 2), and all-cause mortality (n = 4).

CONCLUSION

There is a growing body of research, across different jurisdictions, reporting associations of UOGD with adverse health outcomes. Despite the rapid growth of UOGD, which is often located in remote, rural, and Indigenous communities, Canadian research on its effects on human health is remarkably sparse. There is a pressing need for additional evidence.

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.

Temporal Trends of Racial and Socioeconomic Disparities in Population Exposures to Upstream Oil and Gas Development in California

People living near oil and gas development are exposed to multiple environmental stressors that pose health risks. Some studies suggest these risks are higher for racially and socioeconomically marginalized people, which may be partly attributable to disparities in exposures. We examined whether racially and socioeconomically marginalized people in California are disproportionately exposed to oil and gas wells and associated hazards. We longitudinally assessed exposure to wells during three time periods (2005-2009, 2010-2014, and 2015-2019) using sociodemographic data at the census block group-level. For each block group and time period, we assessed exposure to new, active, retired, and plugged wells, and cumulative production volume. We calculated risk ratios to determine whether marginalized people disproportionately resided near wells (within 1 km). Averaged across the three time periods, we estimated that 1.1 million Californians (3.0%) lived within 1 km of active wells. Nearly 9 million Californians (22.9%) lived within 1 km of plugged wells. The proportion of Black residents near active wells was 42%-49% higher than the proportion of Black residents across California, and the proportion of Hispanic residents near active wells was 4%-13% higher than their statewide proportion. Disparities were greatest in areas with the highest oil and gas production, where the proportion of Black residents was 105%-139% higher than statewide. Socioeconomically marginalized residents also had disproportionately high exposure to wells. Though oil and gas production has declined in California, marginalized communities persistently had disproportionately high exposure to wells, potentially contributing to health disparities.

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.

Metal Exposures in Residents Living Near an Urban Oil Drilling Site in Los Angeles, California

Urban environmental justice communities are potentially exposed to multiple toxic metals, through contaminated air, soil, water, and food. However, information on metals and their sources is lacking. This study uses non-negative matrix factorization (NMF) in a community-based participatory research study to identify potential sources and to understand how these metals cluster in a population near an urban oil drilling site. We recruited 203 Latinx, Black, and Asian residents who lived within 1 km of an oil drilling site in south Los Angeles and collected toenail clippings to assess exposure to arsenic (As), cadmium (Cd), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), and antimony (Sb). Using NMF, we identified three clusters based on concentrations in the participants' toenails. As, Cd, Pb, and Sb grouped together, indicative of an industrial source. A second grouping was composed of Ni and Mn, which may be related to oil drilling. We also identified a third source factor predominantly driven by Hg and As, which may arise from dietary sources. Utilizing NMF, a dimension reduction method, we identified a source factor high in Ni and Mn in residents living in a neighborhood near an active oil drilling site.

Multi-matrix biomonitoring approach to assess exposure to metals and trace elements in the Lebanese population and associations with drinking water consumption

This study is the first attempt to assess exposure to metals and trace elements in subgroups of the Lebanese population using a multi-matrix biomonitoring approach. Concentrations of 11 metals and trace elements (aluminum (Al), arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), selenium (Se), uranium (U), zinc (Zn)) were measured in urine, hair and toenails. Biological levels were compared according to age, sex, smoking status, socioeconomic status, geographical area and drinking water source. While most urinary and toenail concentrations of metals and trace elements were not different between males and females, measured concentrations of several elements in hair were higher in females compared to males. Urinary concentrations of some metals (Al, Cu, Se and Zn) were higher in children compared to teenagers and adults. Hair and toenail concentrations of several elements (As, Cd, Pb, Mn, Se in hair and toenails plus Al, Fe in toenails) were also significantly higher in children compared to teenagers and/or adults. Smoking status had no influence on metal and trace element concentrations. Levels of Cd, Pb and Mn were also higher in samples from subgroups with lower economic status (Cd and Pb in the three matrices and Mn in hair and toenails). Very few correlations were identified between sources of drinking water and urine, hair, and toenail concentrations of metals and trace elements. However, a correlation was observed between hair and toenails levels of As, Cd and Pb. Overall, results highlight that a special attention should be given to metal and trace element exposure in this population (including Pb, As, Cd, Mn, and Se). It could be relevant to scale up this kind of investigation with a large human biomonitoring initiative in the Lebanese population in order to generalize results, and assess trends over time.

Hair Toxic Trace Elements of Residents across the Caspian Oil and Gas Region of Kazakhstan: Cross-Sectional Study

This study aimed to assess the relationship between the content of toxic trace elements, such as aluminum (Al), arsenic (As), beryllium (Be), cadmium (Cd), mercury (Hg), and lead (Pb), in the hair of the adult population of western Kazakhstan and the distance of their residence from oil and gas fields. The cross-sectional study included 850 adults aged 18-60 years. Inductively coupled plasma mass spectrometry was used to measure the level of Al, As, Be, Cd, Hg, and Pb in hair. The relationship between the concentration of toxic trace elements in the hair and the distance from oil and gas fields was assessed in three groups (<16 km, 16-110 km, and >110 km), using multiple linear regression analysis. The highest concentration of Hg = 0.338 μg/g was determined in the group living near oil and gas fields (0-16 km), whereas the lowest concentration of Al = 3.127 μg/g and As = 0.028 μg/g was determined in participants living at a long distance (more than 110 km) (p < 0.001). The concentration of Al (-0.126 (CI: -0.174; -0.077)), Hg (-0.065 (CI: -0.129; -0.001)), and Pb (0.111 (CI: 0.045; 0.177)) is associated with the distance to oil and gas fields. The obtained data indicate a change in the toxic trace element content in the hair of residents in the Caspian region of western Kazakhstan, a change that is most pronounced in residents living in the zone of oil and gas pollution. The distance to the oil and gas fields affects the content of toxic elements in scalp hair. In particular, the concentration of Al and Hg is associated with a decrease in the distance to oil and gas fields, while the concentration of Pb is associated with an increase in the distance to these fields. The lowest content of Al and As was determined in the hair of study participants living in the most remote areas (more than 110 km from oil and gas fields). Our results demonstrate the need for the biomonitoring of toxic elements to determine long-term temporal trends in the impact of chemicals on public health in western Kazakhstan.

Assessing Exposure to Unconventional Oil and Gas Development: Strengths, Challenges, and Implications for Epidemiologic Research

PURPOSE OF REVIEW

Epidemiologic studies have observed elevated health risks in populations living near unconventional oil and gas development (UOGD). In this narrative review, we discuss strengths and limitations of UOG exposure assessment approaches used in or available for epidemiologic studies, emphasizing studies of children's health outcomes.

RECENT FINDINGS

Exposure assessment challenges include (1) numerous potential stressors with distinct spatiotemporal patterns, (2) critical exposure windows that cover long periods and occur in the past, and (3) limited existing monitoring data coupled with the resource-intensiveness of collecting new exposure measurements to capture spatiotemporal variation. All epidemiologic studies used proximity-based models for exposure assessment as opposed to surveys, biomonitoring, or environmental measurements. Nearly all studies used aggregate (rather than pathway-specific) models, which are useful surrogates for the complex mix of potential hazards. Simple and less-specific exposure assessment approaches have benefits in terms of scalability, interpretability, and relevance to specific policy initiatives such as set-back distances. More detailed and specific models and metrics, including dispersion methods and stressor-specific models, could reduce exposure misclassification, illuminate underlying exposure pathways, and inform emission control and exposure mitigation strategies. While less practical in a large population, collection of multi-media environmental and biological exposure measurements would be feasible in cohort subsets. Such assessments are well-suited to provide insights into the presence and magnitude of exposures to UOG-related stressors in relation to spatial surrogates and to better elucidate the plausibility of observed effects in both children and adults.

Essential Trace Elements in Scalp Hair of Residents across the Caspian Oil and Gas Region of Kazakhstan

Most of the country’s oil and gas fields are situated in West Kazakhstan, mainly on the Caspian Sea coast, causing significant damage to the local environment and contributing to an imbalance in the trace element composition of the human body. The study is aimed to evaluate the relationship between the concentration of essential trace elements in scalp hair of the western Kazakhstan adult population and the remoteness of their residence from oil and gas fields. The concentration of essential trace elements (Co, Cu, Fe, I, Mn, Se, Zn) in the hair of 850 individuals aged 18−60 years was determined by inductively coupled plasma mass spectrometry. In residents of settlements located at a distance of >110 km from oil and gas fields, the concentration of Cu and I in hair was significantly higher than in those closer to 110 km (p < 0.001). The content of Cu and I were associated with the distance to oil and gas fields (0.072 (95% CI: 0.050; 0.094)) and (0.121 (95% CI: 0.058; 0.185)), respectively. We detected a significant imbalance in the distribution of some essential trace elements in residents’ scalp hair from the Caspian region of western Kazakhstan, living near oil and gas fields. The concentrations of Cu and I were significantly interrelated with the distance to oil and gas fields. The level of copper in the hair of both inhabitants of the area most remote from oil and gas facilities and the entire population of western Kazakhstan as a whole remains significantly low. The data obtained provide evidence of the possible impact of pollutants generated by the oil and gas facilities on a shortage of essential trace elements and associated subsequent health risks.

Association Between Residential Proximity to Hydraulic Fracturing Sites and Adverse Birth Outcomes

IMPORTANCE

The association between hydraulic fracturing and human development is not well understood. Several studies have identified significant associations between unconventional natural gas development and adverse birth outcomes; however, geology and legislation vary between regions.

OBJECTIVE

To examine the overall association between residential proximity to hydraulic fracturing sites and adverse birth outcomes, and investigate whether well density influenced this association.

DESIGN, SETTING, AND PARTICIPANTS

This population-based retrospective cohort study of pregnant individuals in rural Alberta, Canada, took place from 2013 to 2018. Participants included reproductive-aged individuals (18-50 years) who had a pregnancy from January 1, 2013, to December 31, 2018, and lived in rural areas. Individuals were excluded if they lived in an urban setting, were outside of the age range, or were missing data on infant sex, postal code, or area-level socioeconomic status.

EXPOSURES

Oil and gas wells that underwent hydraulic fracturing between 2013 to 2018 were identified through the Alberta Energy Regulator (n = 4871). Individuals were considered exposed if their postal delivery point was located within 10 km of 1 or more wells that was hydraulically fractured during 1 year preconception or during pregnancy.

MAIN OUTCOMES AND MEASURES

Outcomes investigated were spontaneous and indicated preterm birth, small for gestational age, major congenital anomalies, and severe neonatal morbidity or mortality.

RESULTS

After exclusions, the sample included 26 193 individuals with 34 873 unique pregnancies, and a mean (SD) parental age of 28.2 (5.2) years. Small for gestational age and major congenital anomalies were significantly higher for individuals who lived within 10 km of at least 1 hydraulically fractured well after adjusting for parental age at delivery, multiple births, fetal sex, obstetric comorbidities, and area-level socioeconomic status. Risk of spontaneous preterm birth and small for gestational age were significantly increased in those with 100 or more wells within 10 km.

CONCLUSIONS AND RELEVANCE

Results suggest that individuals who were exposed to hydraulic fracturing within pregnancy may be at higher risk of several adverse birth outcomes. These results may be relevant to health policy regarding legislation of unconventional oil and gas development in Canada and internationally.

Associations between residential proximity to oil and gas extraction and hypertensive conditions during pregnancy: a difference-in-differences analysis in Texas, 1996-2009

BACKGROUND

Oil and gas extraction produces air pollutants that are associated with increased risks of hypertension. To date, no study has examined residential proximity to oil and gas extraction and hypertensive conditions during pregnancy. This study quantifies associations between residential proximity to oil and gas development on gestational hypertension and eclampsia.

METHODS

We utilized a population-based retrospective birth cohort in Texas (1996-2009), where mothers reside <10 km from an active or future drilling site (n = 2 845 144.) Using full-address data, we linked each maternal residence at delivery to assign exposure and evaluate this exposure with respect to gestational hypertension and eclampsia. In a difference-in-differences framework, we model the interaction between maternal health before (unexposed) or after (exposed) the start of drilling activity (exposed) and residential proximity near (0-1, >1-2 or >2-3 km) or far (≥3-10 km) from an active or future drilling site.

RESULTS

Among pregnant women residing 0-1 km from an active oil or gas extraction site, we estimate 5% increased odds of gestational hypertension [95% confidence interval (CI): 1.00, 1.10] and 26% increased odds of eclampsia (95% CI: 1.05, 1.51) in adjusted models. This association dissipates in the 1- to 3-km buffer zones. In restricted models, we find elevated odds ratios among maternal ages ≤35 years at delivery, maternal non-Hispanic White race, ≥30 lbs gained during pregnancy, nulliparous mothers and maternal educational attainment beyond high school.

CONCLUSIONS

Living within 1 km of an oil or gas extraction site during pregnancy is associated with increased odds of hypertensive conditions during pregnancy.

Hair mineral analysis in the population of students living in the Lower Silesia region (Poland) in 2019: Comparison with biomonitoring study in 2009 and literature data

The paper presents a comparative analysis of biomonitoring research results using hair mineral analysis today and 10 years ago. The aim of the present work was to examine the impact of individual factors, on the content of elements in human hair. The mineral analysis of 115 hair samples was carried out using ICP-OES and AAS technique. It was shown that calcium, barium, copper, mercury, magnesium, manganese and selenium content depend on gender and is higher for women. Statistically significant synergistic correlations were identified between the following pairs of elements: (Ca-Mg), (P-S), (Mo-Sb) and (Ba-Pb). The results of the present work were compared with the previous assessment in 2009 on students of the same age. The content of most of the heavy metals in hair was reduced significantly, which is a sign of the improving state of the local environment. The greatest decrease was recorded for silver (96.6%), arsenic (93.4%), mercury (45.1%), lead (67.7%), antimony (55.2%), thallium (10 times) and cobalt (93.7%). The level of the following elements increased: Ba: 27.3%, Cu: 28.5%, Ni: 22.4%, Ti: 191%, Zn: 11.0%. Changes in the content of most heavy metals in hair have been noted, as well as changes of reference ranges, which may indicate an improvement in the state of the environment in Wrocław, Lower Silesia (Poland) over the last 10 years. These results were confirmed by biomonitoring studies carried out with human hair, which was shown to be a reliable biomarker of human exposure to toxic elements.

Human biomonitoring results of contaminant and nutrient biomarkers in Old Crow, Yukon, Canada

Several large-scale human biomonitoring projects have been conducted in Canada, including the Canadian Health Measures Survey (CHMS) and the First Nations Biomonitoring Initiative (FNBI). However, neither of these studies included participants living in the Yukon. To address this data gap, a human biomonitoring project was implemented in Old Crow, a fly-in Gwich'in community in the northern Yukon. The results of this project provide baseline levels of contaminant and nutrient biomarkers from Old Crow in 2019. Samples of hair, blood, and/or urine were collected from approximately 44% of community residents (77 of 175 adults). These samples were analyzed for contaminants (including heavy metals and persistent organic pollutants (POPs)), and nutrients (including trace elements and omega-3 fatty acids). Levels of these analytes were compared to health-based guidance values, when available, and results from other human biomonitoring projects in Canada. Levels of lead (GM 0.64 μg/g creatinine in urine/24 μg/L blood), cadmium (GM 0.32 μg/g creatinine in urine/0.85 μg/L blood), and mercury (GM < LOD in urine/0.76 μg/L blood/0.31 μg/g hair) were below select health-based guidance values for more than 95% of participants. However, compared to the general Canadian population, elevated levels of some contaminants, including lead (approximately 2× higher), cobalt (approximately 1.5× higher), manganese (approximately 1.3× higher), and hexachlorobenzene (approximately 1.5× higher) were observed. In contrast, levels of other POPs, including insecticides such as dichlorodiphenyltrichloroethane (DDT), its metabolite, dichlorodiphenyldichloroethylene (DDE), and polychlorinated biphenyls (PCBs) were similar to, or lower than, those reported in the general Canadian population. This study can be used along with future biomonitoring programs to evaluate the effectiveness of international initiatives designed to reduce the contaminant burden in the Arctic, including the Stockholm Convention and the Minamata Convention. Regionally, this project complements environmental monitoring being conducted in the region, informing local and regional traditional food consumption advisories.

A feasibility study of metabolic phenotyping of dried blood spot specimens in rural Chinese women exposed to household air pollution

BACKGROUND

Exposure-response studies and policy evaluations of household air pollution (HAP) are limited by current methods of exposure assessment which are expensive and burdensome to participants.

METHODS

We collected 152 dried blood spot (DBS) specimens during the heating and non-heating seasons from 53 women who regularly used biomass-burning stoves for cooking and heating. Participants were enrolled in a longitudinal study in China. Untargeted metabolic phenotyping of DBS were generated using ultra-high performance liquid chromatography coupled with mass spectrometry to exemplify measurement precision and assessment for feasibility to detect exposure to HAP, evaluated by season (high pollution vs. low pollution) and measured personal exposure to fine particulate matter <2.5 μm diameters (PM2.5) and black carbon (BC) in the 48-h prior to collecting the DBS specimen.

RESULTS

Metabolites e.g., amino acids, acyl-carnitines, lyso-phosphorylcholines, sphinganine, and choline were detected in the DBS specimens. Our approach is capable of detecting the differences in personal exposure to HAP whilst showing high analytical reproducibility, coefficient of variance (CV) <15%, meeting the U.S. Food and Drug Administration criteria.

CONCLUSIONS

Our results provide a proof of principle that high-resolution metabolic phenotypic data can be generated using a simple DBS extraction method thus suitable for exposure studies in remote, low-resource settings where the collection of serum and plasma is logistically challenging or infeasible. The analytical run time (19 min/specimen) is similar to most global phenotyping methods and therefore suitable for large-scale application.

Density and proximity to hydraulic fracturing wells and birth outcomes in Northeastern British Columbia, Canada

BACKGROUND

Hydraulic fracturing, a method used in Northeastern British Columbia (Canada) to extract natural gas, can release contaminants with potential deleterious health effects on fetal development. To date, the association between hydraulic fracturing activity and birth outcomes has not been evaluated in this region.

OBJECTIVE

To evaluate the association between the hydraulic fracturing well density/proximity and birth outcomes (birthweight, head circumference, preterm birth and small for gestational age (SGA)).

METHODS

We used birth records from the Fort St John hospital between December 30, 2006 and December 29, 2016 (n = 6333 births). To estimate gestational exposure, we used inverse distance weighting (IDW) to calculate the density/proximity of hydraulic fracturing wells to pregnant women's postal code centroid. For each birth, we calculated three IDWs using 2.5, 5, and 10 km buffer zones around women's postal code centroid. We used linear and logistic regressions to evaluate associations between quartiles of postal code well density/proximity and birth outcomes, controlling for relevant covariates.

RESULTS

No associations were found between postal code well density/proximity and head circumference or SGA. A negative association was found between postal code well density/proximity and birthweight for infants born to women in the 2nd quartile of the 10 km buffer (β [95% confidence interval (CI)]: -47.28 g [-84.30; -10.25]), and in the 2nd (β [95% CI]: -40.87 g [-78.01; -3.73]) and 3rd (β [95% CI]: -42.01 g [-79.15; -4.87]) quartiles of the 5 km buffer. Increased odds of preterm birth were observed among women in the 2nd quartile of the 2.5 km buffer (odds ratio (OR) [95% CI]: 1.60 [1.30; 2.43]).

CONCLUSIONS

This is the first epidemiological study in Northeastern British Columbia evaluating associations between hydraulic fracturing and health outcomes. Our results show inconsistent patterns of association between hydraulic fracturing, preterm birth and reduced birthweight, and effect estimates did not match expected dose-response relationships.

Chemical Exposures, Health, and Environmental Justice in Communities Living on the Fenceline of Industry

PURPOSE OF REVIEW

Polluting industries are more likely to be located in low-income communities of color who also experience greater social stressors that may make them more vulnerable than others to the health impacts of toxic chemical exposures. We describe recent developments in assessing pollutant exposures and health threats posed by industrial facilities using or releasing synthetic chemicals to nearby communities in the U.S.

RECENT FINDINGS

More people are living near oil and gas development due to the expansion of unconventional extraction techniques as well as near industrial animal operations, both with suggestive evidence of increased exposure to hazardous pollutants and adverse health effects. Legacy contamination continues to adversely impact a new generation of residents in fenceline communities, with recent studies documenting exposures to toxic metals and poly- and perfluoroalkyl substances (PFASs). Researchers are also giving consideration to acute exposures resulting from inadvertent industrial chemical releases, including those resulting from extreme weather events linked to climate change. Natural experiments of industrial closures or cleanups provide compelling evidence that exposures from industry harm the health of nearby residents. New and legacy industries, coupled with climate change, present unique health risks to communities living near industry due to the release of toxic chemicals. Cumulative impacts from multiple stressors faced by environmental justice communities may amplify these adverse effects.