Petroleum hydrocarbon (PHC) uptake in plants: A literature review.

Crude oil and its constituents can have adverse effects on ecological and human health when released into the environment. The Canadian Council of Ministers of the Environment (CCME) has developed remedial guidelines and a risk assessment framework for both ecological and human exposure to PHC. One of the assumptions used in the derivation of these guidelines is that plants are unable to take up PHC from contaminated soil and therefore subsequent exposure at higher trophic levels is not a concern. However, various studies suggest that plants are indeed able to take up PHC into their tissues. Consumption of plants is a potential exposure pathway in both ecological (e.g., herbivorous and omnivorous birds, and mammals) and human health risk assessments. If plants can uptake PHC, then the current approach for risk assessment of PHC may underestimate exposures to ecological and human receptors. The present review aims to assess whether or not plants are capable of PHC uptake and accumulation. Twenty-one articles were deemed relevant to the study objective and form the basis of this review. Of the 21 primary research articles, 19 reported detectable PHC and/or its constituents in plant tissues. All but five of the 21 articles were published after the publication of the CCME Canada-Wide Standards. Overall, the present literature review provides some evidence of uptake of PHC and its constituents into plant tissues. Various plant species, including some edible plants, were shown to take up PHC from contaminated soil and aqueous media in both laboratory and field studies. Based on the findings of this review, it is recommended that the soil-plant-wildlife/human pathway should be considered in risk assessments to avoid underestimating exposure and subsequent toxicological risks to humans and wildlife.

Extended fish short term reproduction assays with the fathead minnow and Japanese medaka: No evidence of impaired fecundity from exposure to atrazine.

Short-term reproduction assays were conducted with fathead minnow (Pimephales promelas) and Japanese medaka (Oryzias latipes) to evaluate responses from atrazine exposure at environmentally relevant concentrations and above. Breeding groups of fish with multiple males and females were exposed to atrazine under flow-through conditions. Fathead minnows were exposed to mean measured concentrations of 1.0, 10, 26, 52, and 105 µg atrazine/L for 28 days. Medaka were exposed to mean measured concentrations of 9.4, 48, 74, 97, and 244 µg atrazine/L for 28 or 29 days. Fish were evaluated for survival, fecundity, fertility, total length, wet weight, secondary sex characteristics, gonadosomatic index (GSI) (P. promelas only), plasma or hepatic vitellogenin (VTG), and histopathology of gonads. General observations of health and behaviour were also conducted. There were no statistically significant effects (i.e., p < 0.05) of atrazine on survival, size, reproduction, behaviour, GSI, VTG, or secondary sex characteristics in either species at any exposure level. In fathead minnows, there were no histopathological findings associated with atrazine exposure in male fish, but there was an increased proportion of Stage 4.0 ovaries accompanied by an increase in proportion of Grade 3 post-ovulatory follicles in females of the 105 µg/L treatment group. Without a concomitant increase in oocyte atresia, neither of these findings are considered adverse for the health of the fish. In medaka, there were no significant effects of atrazine exposure on histopathology in either sex. These data support current weight-of-evidence assessments that atrazine does not cause direct adverse effects on fish reproduction at environmentally realistic concentrations.

A refined ecological risk assessment for California red-legged frog, Delta smelt, and California tiger salamander exposed to malathion.

The California red-legged frog (CRLF), Delta smelt (DS), and California tiger salamander (CTS) are 3 species listed under the United States Federal Endangered Species Act (ESA), all of which inhabit aquatic ecosystems in California. The US Environmental Protection Agency (USEPA) has conducted deterministic screening-level risk assessments for these species potentially exposed to malathion, an organophosphorus insecticide and acaricide. Results from our screening-level analyses identified potential risk of direct effects to DS as well as indirect effects to all 3 species via reduction in prey. Accordingly, for those species and scenarios in which risk was identified at the screening level, we conducted a refined probabilistic risk assessment for CRLF, DS, and CTS. The refined ecological risk assessment (ERA) was conducted using best available data and approaches, as recommended by the 2013 National Research Council (NRC) report "Assessing Risks to Endangered and Threatened Species from Pesticides." Refined aquatic exposure models including the Pesticide Root Zone Model (PRZM), the Vegetative Filter Strip Modeling System (VFSMOD), the Variable Volume Water Model (VVWM), the Exposure Analysis Modeling System (EXAMS), and the Soil and Water Assessment Tool (SWAT) were used to generate estimated exposure concentrations (EECs) for malathion based on worst-case scenarios in California. Refined effects analyses involved developing concentration-response curves for fish and species sensitivity distributions (SSDs) for fish and aquatic invertebrates. Quantitative risk curves, field and mesocosm studies, surface-water monitoring data, and incident reports were considered in a weight-of-evidence approach. Currently, labeled uses of malathion are not expected to result in direct effects to CRLF, DS or CTS, or indirect effects due to effects on fish and invertebrate prey. Integr Environ Assess Manag 2018;14:224-239. © 2017 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Fish short-term reproduction assay with atrazine and the Japanese medaka (Oryzias latipes).

Breeding groups of Japanese medaka (Oryzias latipes) were exposed to atrazine at measured concentrations of 0.6, 5.5, and 53 µg/L for 35 d. Evaluated endpoints included survival, fecundity, fertility, growth (weight and length), behavior, secondary sex characteristics (anal fin papillae), gonad histopathology, and hepatic vitellogenin. No statistically significant effects of atrazine exposure on survival and growth of medaka were noted during the test, and mean survival was ≥97.5% in all treatment groups on day 35. No significant effects of atrazine exposure on reproduction were observed. The number of mean cumulative eggs produced in the negative control and the 0.6, 5.5, and 53 µg/L treatment groups was 7158, 6691, 6883, and 6856, respectively. The mean number of eggs per female reproductive day was 40.9, 38.2, 40.2, and 39.2, respectively. There were also no dose-dependent effects on mean anal fin papillae counts among male fish or expression of vtg-II in males or females. In addition, atrazine exposure was not related to the developmental stage of test fish, with testes stages ranging from 2 to 3 in all groups and ovaries ranging from stage 2 to 2.5. Overall, exposure to atrazine up to 53 µg/L for 35 d did not result in significant, treatment-related effects on measured endpoints related to survival, growth, or reproduction in Japanese medaka. Environ Toxicol Chem 2017;36:2327-2334. © 2017 SETAC.

Sugar concentration in nectar: a quantitative metric of crop attractiveness for refined pollinator risk assessments.

Those involved with pollinator risk assessment know that agricultural crops vary in attractiveness to bees. Intuitively, this means that exposure to agricultural pesticides is likely greatest for attractive plants and lowest for unattractive plants. While crop attractiveness in the risk assessment process has been qualitatively remarked on by some authorities, absent is direction on how to refine the process with quantitative metrics of attractiveness. At a high level, attractiveness of crops to bees appears to depend on several key variables, including but not limited to: floral, olfactory, visual and tactile cues; seasonal availability; physical and behavioral characteristics of the bee; plant and nectar rewards. Notwithstanding the complexities and interactions among these variables, sugar content in nectar stands out as a suitable quantitative metric by which to refine pollinator risk assessments for attractiveness. Provided herein is a proposed way to use sugar nectar concentration to adjust the exposure parameter (with what is called a crop attractiveness factor) in the calculation of risk quotients in order to derive crop-specific tier I assessments. This Perspective is meant to invite discussion on incorporating such changes in the risk assessment process. © 2016 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

A multiple lines of evidence approach for the ecological risk assessment of an accidental bitumen release from a steam assisted gravity drainage (SAGD) well in the Athabasca oil sands region.

To assess the ecological impacts of two independent accidental bitumen releases from two steam assisted gravity drainage (SAGD) wells in the Athabasca oil sands region, a multiple lines of evidence (LOE) approach was developed. Following the release in 2010, action was taken to minimize environmental impact, including the selective removal of the most highly impacted vegetation and the use of oil socks to minimize possible runoff. An ecological risk assessment (ERA) was then conducted based on reported concentrations of bitumen related contaminants in soil, vegetation, and water. Results of biological assessments conducted at the site were also included in the risk characterization. Overall, the conclusion of the ERA was that the likelihood of long-term adverse health effects to ecological receptors in the area was negligible. To provide evidence for this conclusion, a small mammal sampling plan targeting Southern red-back voles (Myodes gapperi) was carried out at two sites and two relevant reference areas. Voles were readily collected at all locations and no statistically significant differences in morphometric measurements (i.e., body mass, length, foot length, and adjusted liver weight) were found between animals collected from impact zones of varying levels of coverage. Additionally, no trends corresponding with bitumen coverage were observed with respect to metal body burden in voles for metals that were previously identified in the source bitumen. Hepatic ethoxyresorufin-O-deethylase (EROD) activity was statistically significantly elevated in voles collected from the high impact zones of sites compared to those collected from the reference areas, a finding that is indicative of continued exposure to contaminants. However, this increase in EROD was not correlated with any observable adverse population-wide biological outcomes. Therefore the biological sampling program supported the conclusion of the initial ERA and supported the hypothesis of no significant long-term population-wide ecological impact of the accidental bitumen releases.

Health-based audible noise guidelines account for infrasound and low-frequency noise produced by wind turbines.

Setbacks for wind turbines have been established in many jurisdictions to address potential health concerns associated with audible noise. However, in recent years, it has been suggested that infrasound (IS) and low-frequency noise (LFN) could be responsible for the onset of adverse health effects self-reported by some individuals living in proximity to wind turbines, even when audible noise limits are met. The purpose of this paper was to investigate whether current audible noise-based guidelines for wind turbines account for the protection of human health, given the levels of IS and LFN typically produced by wind turbines. New field measurements of indoor IS and outdoor LFN at locations between 400 and 900 m from the nearest turbine, which were previously underrepresented in the scientific literature, are reported and put into context with existing published works. Our analysis showed that indoor IS levels were below auditory threshold levels while LFN levels at distances >500 m were similar to background LFN levels. A clear contribution to LFN due to wind turbine operation (i.e., measured with turbines on in comparison to with turbines off) was noted at a distance of 480 m. However, this corresponded to an increase in overall audible sound measures as reported in dB(A), supporting the hypothesis that controlling audible sound produced by normally operating wind turbines will also control for LFN. Overall, the available data from this and other studies suggest that health-based audible noise wind turbine siting guidelines provide an effective means to evaluate, monitor, and protect potential receptors from audible noise as well as IS and LFN.

Wind turbines and human health.

The association between wind turbines and health effects is highly debated. Some argue that reported health effects are related to wind turbine operation [electromagnetic fields (EMF), shadow flicker, audible noise, low-frequency noise, infrasound]. Others suggest that when turbines are sited correctly, effects are more likely attributable to a number of subjective variables that result in an annoyed/stressed state. In this review, we provide a bibliographic-like summary and analysis of the science around this issue specifically in terms of noise (including audible, low-frequency noise, and infrasound), EMF, and shadow flicker. Now there are roughly 60 scientific peer-reviewed articles on this issue. The available scientific evidence suggests that EMF, shadow flicker, low-frequency noise, and infrasound from wind turbines are not likely to affect human health; some studies have found that audible noise from wind turbines can be annoying to some. Annoyance may be associated with some self-reported health effects (e.g., sleep disturbance) especially at sound pressure levels >40 dB(A). Because environmental noise above certain levels is a recognized factor in a number of health issues, siting restrictions have been implemented in many jurisdictions to limit noise exposure. These setbacks should help alleviate annoyance from noise. Subjective variables (attitudes and expectations) are also linked to annoyance and have the potential to facilitate other health complaints via the nocebo effect. Therefore, it is possible that a segment of the population may remain annoyed (or report other health impacts) even when noise limits are enforced. Based on the findings and scientific merit of the available studies, the weight of evidence suggests that when sited properly, wind turbines are not related to adverse health. Stemming from this review, we provide a number of recommended best practices for wind turbine development in the context of human health.

Measuring electromagnetic fields (EMF) around wind turbines in Canada: is there a human health concern?

BACKGROUND: The past five years has seen considerable expansion of wind power generation in Ontario, Canada. Most recently worries about exposure to electromagnetic fields (EMF) from wind turbines, and associated electrical transmission, has been raised at public meetings and legal proceedings. These fears have not been based on any actual measurements of EMF exposure surrounding existing projects but appear to follow from worries from internet sources and misunderstanding of the science. METHODS: The study was carried out at the Kingsbridge 1 Wind Farm located near Goderich, Ontario, Canada. Magnetic field measurements were collected in the proximity of 15 Vestas 1.8 MW wind turbines, two substations, various buried and overhead collector and transmission lines, and nearby homes. Data were collected during three operational scenarios to characterize potential EMF exposure: 'high wind' (generating power), 'low wind' (drawing power from the grid, but not generating power) and 'shut off' (neither drawing, nor generating power). RESULTS: Background levels of EMF (0.2 to 0.3 mG) were established by measuring magnetic fields around the wind turbines under the 'shut off' scenario. Magnetic field levels detected at the base of the turbines under both the 'high wind' and 'low wind' conditions were low (mean = 0.9 mG; n = 11) and rapidly diminished with distance, becoming indistinguishable from background within 2 m of the base. Magnetic fields measured 1 m above buried collector lines were also within background (≤ 0.3 mG). Beneath overhead 27.5 kV and 500 kV transmission lines, magnetic field levels of up to 16.5 and 46 mG, respectively, were recorded. These levels also diminished rapidly with distance. None of these sources appeared to influence magnetic field levels at nearby homes located as close as just over 500 m from turbines, where measurements immediately outside of the homes were ≤ 0.4 mG. CONCLUSIONS: The results suggest that there is nothing unique to wind farms with respect to EMF exposure; in fact, magnetic field levels in the vicinity of wind turbines were lower than those produced by many common household electrical devices and were well below any existing regulatory guidelines with respect to human health.

Site specific risk assessment of an energy-from-waste thermal treatment facility in Durham Region, Ontario, Canada. Part A: Human health risk assessment.

The regions of Durham and York in Ontario, Canada have partnered to construct an energy-from-waste thermal treatment facility as part of a long term strategy for the management of their municipal solid waste. This paper presents the results of a comprehensive human health risk assessment for this facility. This assessment was based on extensive sampling of baseline environmental conditions (e.g., collection and analysis of air, soil, water, and biota samples) as well as detailed site specific modeling to predict facility-related emissions of 87 identified contaminants of potential concern. Emissions were estimated for both the approved initial operating design capacity of the facility (140,000 tonnes per year) and for the maximum design capacity (400,000 tonnes per year). For the 140,000 tonnes per year scenario, this assessment indicated that facility-related emissions are unlikely to cause adverse health risks to local residents, farmers, or other receptors (e.g., recreational users). For the 400,000 tonnes per year scenarios, slightly elevated risks were noted with respect to inhalation (hydrogen chloride) and infant consumption of breast milk (dioxins and furans), but only during predicted 'upset conditions' (i.e. facility start-up, shutdown, and loss of air pollution control) that represent unusual and/or transient occurrences. However, current provincial regulations require that additional environmental screening would be mandatory prior to expansion of the facility beyond the initial approved capacity (140,000 tonnes per year). Therefore, the potential risks due to upset conditions for the 400,000 tonnes per year scenario should be more closely investigated if future expansion is pursued.

Site specific risk assessment of an energy-from-waste/thermal treatment facility in Durham Region, Ontario, Canada. Part B: Ecological risk assessment.

The regions of Durham and York in Ontario, Canada have partnered to construct an energy-from-waste (EFW) thermal treatment facility as part of a long term strategy for the management of their municipal solid waste. In this paper we present the results of a comprehensive ecological risk assessment (ERA) for this planned facility, based on baseline sampling and site specific modeling to predict facility-related emissions, which was subsequently accepted by regulatory authorities. Emissions were estimated for both the approved initial operating design capacity of the facility (140,000 tonnes per year) and the maximum design capacity (400,000 tonnes per year). In general, calculated ecological hazard quotients (EHQs) and screening ratios (SRs) for receptors did not exceed the benchmark value (1.0). The only exceedances noted were generally due to existing baseline media concentrations, which did not differ from those expected for similar unimpacted sites in Ontario. This suggests that these exceedances reflect conservative assumptions applied in the risk assessment rather than actual potential risk. However, under predicted upset conditions at 400,000 tonnes per year (i.e., facility start-up, shutdown, and loss of air pollution control), a potential unacceptable risk was estimated for freshwater receptors with respect to benzo(g,h,i)perylene (SR=1.1), which could not be attributed to baseline conditions. Although this slight exceedance reflects a conservative worst-case scenario (upset conditions coinciding with worst-case meteorological conditions), further investigation of potential ecological risk should be performed if this facility is expanded to the maximum operating capacity in the future.

Assessing the genotoxic potential of chlorothalonil drift from potato fields in Prince Edward Island, Canada.

Chlorothalonil, a broad-spectrum nonsystemic foliar fungicide, is one of the most extensively used pesticide active ingredients on Prince Edward Island, Canada, for blight control on potatoes. In ambient air-sampling programs conducted in 1998 and 1999 and from 2002 to 2004, chlorothalonil was measured in 97% of air samples collected. It is known to produce severe eye and skin irritation, is cytogenic and is considered a possible human carcinogen by the United States Environmental Protection Agency and the International Agency for Research on Cancer. Inhalation studies that quantify chlorothalonil subchronic effects (e.g., genotoxicity) are lacking. The purpose of this study was to assess the possible genotoxic potential of chlorothalonil under field conditions by using the alkaline comet assay to assess DNA damage in CD-1 mice. Mice were selected as a surrogate species for wild small mammals (e.g., meadow voles, deer mice) known to inhabit areas adjacent to potato fields. Mice were placed at three locations downwind of a chlorothalonil application (0, 30, and 100 m) and at one up-wind control location at least 30 m from the field. Downwind mice were exposed to drift throughout the spray period (approximately 30 min) and for an additional hour after spraying. Air samples were collected during the spray trials (before, during, and after spraying) using high-volume polyurethane foam and PM(2.5) air samplers. Pesticide deposits were measured using 20 × 25 cm glass-fibre filters. After exposure, blood was collected from each mouse, and DNA strand breaks in white blood cells measured using comet assay. Results suggest that metrics of DNA damage [tail length (TL), percent DNA in tail] were not significantly related to total air chlorothalonil concentration from the three spray trials (r (2) = 0.000, P = 0.907 for TL; r (2) = 0.001, P = 0.874 for percent DNA). In addition, no significant difference in DNA damage was observed between exposed (at 0 m) and control animals (P = 0.357 for TL; P = 0.958 for percent DNA). Based on these results it can be concluded that wild small mammals living beside fields sprayed with chlorothalonil are at no greater risk of exposure-related DNA damage than conspecifics from unexposed areas.

Inclusion of soil arsenic bioaccessibility in ecological risk assessment and comparison with biological effects.

The purpose of this study was to conduct an ecological risk assessment (ERA) for meadow voles (Microtus pennslvanicus) found at three arsenic contaminated sites in Nova Scotia, Canada (as well as two background locations) and to compare the numeric results to measured biomarkers of exposure and effect. The daily intake of arsenic by meadow voles was determined by three separate calculations: estimated daily intake (EDI), bioaccessible estimated daily intake (BEDI, with bioaccessibility of soil included), and actual daily intake (ADI, which is calculated with arsenic concentrations in the stomach contents). The median bioaccessibility of arsenic in soils from the contaminated locations was significantly greater than at background locations. The bioaccessible arsenic concentration in soil from all samples (both contaminated and background) was significantly less than the total concentration. Use of site-specific bioaccessibility (hazard quotients=38 at Upper Seal Harbour (USH); 60 at Lower Seal Harbour (LSH); and 120 at Montague tailings (MONT)) and stomach arsenic contents (hazard quotients=2.1 at USH; 7.9 at LSH; and 6.7 at MONT) in the ERA resulted in lower numeric risk than compared to risk calculated with 100% bioavailability (hazard quotient=180 at USH; 75 at LSH; and 680 at MONT). Further, the use of bioaccessibility on the calculation of risk was aligned with biomarker results (changes in glutathione and micronucleated erythrocytes) in voles captured at the sites. This study provides evidence that using site-specific bioaccessibility in ERAs may provide a more realistic level of conservatism, thereby enhancing the accuracy of predicting risk to wildlife receptors. Furthermore, when numeric risk assessments are combined with site-specific biological data (i.e., biomarkers of exposure and effect), both lines of evidence can be used to make informed decisions about ecological risk and site management.

Health effects and wind turbines: a review of the literature.

BACKGROUND: Wind power has been harnessed as a source of power around the world. Debate is ongoing with respect to the relationship between reported health effects and wind turbines, specifically in terms of audible and inaudible noise. As a result, minimum setback distances have been established world-wide to reduce or avoid potential complaints from, or potential effects to, people living in proximity to wind turbines. People interested in this debate turn to two sources of information to make informed decisions: scientific peer-reviewed studies published in scientific journals and the popular literature and internet. METHODS: The purpose of this paper is to review the peer-reviewed scientific literature, government agency reports, and the most prominent information found in the popular literature. Combinations of key words were entered into the Thomson Reuters Web of KnowledgeSM and the internet search engine Google. The review was conducted in the spirit of the evaluation process outlined in the Cochrane Handbook for Systematic Reviews of Interventions. RESULTS: Conclusions of the peer reviewed literature differ in some ways from those in the popular literature. In peer reviewed studies, wind turbine annoyance has been statistically associated with wind turbine noise, but found to be more strongly related to visual impact, attitude to wind turbines and sensitivity to noise. To date, no peer reviewed articles demonstrate a direct causal link between people living in proximity to modern wind turbines, the noise they emit and resulting physiological health effects. If anything, reported health effects are likely attributed to a number of environmental stressors that result in an annoyed/stressed state in a segment of the population. In the popular literature, self-reported health outcomes are related to distance from turbines and the claim is made that infrasound is the causative factor for the reported effects, even though sound pressure levels are not measured. CONCLUSIONS: What both types of studies have in common is the conclusion that wind turbines can be a source of annoyance for some people. The difference between both types is the reason for annoyance. While it is acknowledged that noise from wind turbines can be annoying to some and associated with some reported health effects (e.g., sleep disturbance), especially when found at sound pressure levels greater than 40 db(A), given that annoyance appears to be more strongly related to visual cues and attitude than to noise itself, self reported health effects of people living near wind turbines are more likely attributed to physical manifestation from an annoyed state than from wind turbines themselves. In other words, it appears that it is the change in the environment that is associated with reported health effects and not a turbine-specific variable like audible noise or infrasound. Regardless of its cause, a certain level of annoyance in a population can be expected (as with any number of projects that change the local environment) and the acceptable level is a policy decision to be made by elected officials and their government representatives where the benefits of wind power are weighted against their cons. Assessing the effects of wind turbines on human health is an emerging field and conducting further research into the effects of wind turbines (and environmental changes) on human health, emotional and physical, is warranted.

Impacts of traditional food consumption advisories: compliance, changes in diet and loss of confidence in traditional foods.

BACKGROUND: Food consumption advisories are often posted when industrial activities are expected to affect the quality and availability of traditional foods used by First Nations. We were recently involved in a project and asked to summarize details regarding the impacts of traditional food consumption advisories with respect to compliance, broader changes in diet and loss of confidence in traditional foods by people. METHODS: Our review was not conducted as a formal systematic comprehensive review; rather, we focused on primary and grey literature presenting academic, health practitioner and First Nations viewpoints on the topic available from literature databases (i.e., PubMed, Web of Knowledge (SM)) as well as the internet search engine Google. Some information came from personal communications. RESULTS: Our overview suggests that when communicated effectively and clearly, and when community members are involved in the process, consumption advisories can result in a decrease in contaminant load in people. On the other hand, consumption advisories can lead to cultural loss and have been linked to a certain amount of social, psychological, nutritional, economic and lifestyle disruption. In some cases, communities have decided to ignore consumption advisories opting to continue with traditional lifestyles believing that the benefits of doing so outweigh the risk of following advisories. CONCLUSIONS: We identified that there are both positive and negative aspects to the issuance of traditional food consumption advisories. A number of variables need to be recognized during the development and implementation of advisories in order to ensure a balance between human health, maintenance of cultures and industrial activity.

Arsenic transformations in terrestrial small mammal food chains from contaminated sites in Canada.

Arsenic in terrestrial contaminated sites has the potential to cause harm to residential wildlife. The aim of this study was to determine the arsenic species in wild rodents living in arsenic contaminated habitats, specifically deer mice from Yellowknife, NT and meadow voles from Seal Harbour, NS, along with co-located plants. Methanol : water (1 : 1) extractions were used to optimize the extraction of methylated arsenic(v) species. Total arsenic concentrations were substantially higher in the Yellowknife deer mice (1.7-3.2 µg kg(-1) wet weight in livers) and Seal Harbour meadow voles (0.67-0.97 µg kg(-1) wet weight in livers) living on the contaminated sites with respect to the surrounding background locations (0.12-0.34 µg kg(-1) wet weight in livers). Around 50% of arsenic could be identified in Yellowknife deer mouse tissues, but only <10% was identified in Seal Harbour vole tissues; inorganic arsenic (iii and v) and dimethylarsinic acid were all found. Monomethylarsonic acid was only detected in both the mice and voles living in the contaminated sites. In the Yellowknife food chain, methyl arsenic (v) proportions increased from plants to mouse inner organs, but the trend was not for clear as the Seal Harbour food chain. Seal Harbour voles may be sequestering arsenic in a less mobile form, rather than transforming it.

Arsenic transformations and biomarkers in meadow voles (Microtus pennsylvanicus) living on an abandoned gold mine site in Montague, Nova Scotia, Canada.

Arsenic is one of the most widely encountered environmental contaminants because of a number of anthropogenic sources; in Canada the main anthropogenic release of arsenic is from mine tailings ponds. The present study is part of a series of studies to measure chemical and biological effects of exposure for meadow voles (Microtus pennsylvanicus) living on arsenic contaminated sites. Two additional objectives were addressed in the present study: the effect of higher arsenic concentrations compared with previous studies, and the comparison of chemical speciation and biological effects. To obtain the higher environmental concentrations, specimens were collected from a former gold mining site in Montague, NS that contains highly elevated concentrations of arsenic in soils and plants. Meadow voles were collected and their tissues were analyzed for total arsenic to measure uptake, and arsenic speciation to examine the chemical effects of the high arsenic exposure. In addition to the arsenic analysis, a biomonitoring study was undertaken to examine the sub-cellular effects in meadow voles resulting from the elevated arsenic exposure. Meadow voles living on the contaminated site had substantially higher concentrations of total arsenic than animals from the background (reference) location. The extractable arsenic in internal tissues was present mainly as monomethylarsonic acid (up to 14% of total arsenic). A statistically significant relationship was observed between the reduction of glutathione in vole livers and the increase in liver arsenic concentrations, and micronucleated monochromatic red blood cells were also significantly elevated in voles from the arsenic contaminated site. This is one of the few field studies where sub-cellular effects were observed, and the first to show a co-existence of such effects with relatively high proportions of monomethylarsonic acid in voles living near mine tailings.

Use of biomarkers to show sub-cellular effects in meadow voles (Microtus pennsylvanicus) living on an abandoned gold mine site.

Run-off from mine tailings ponds constitutes the main anthropogenic release of arsenic in Canada. As a potential consequence, wildlife not normally exposed to arsenic under other circumstances may receive toxicologically relevant concentrations of arsenic compounds in their food and water. To test this hypothesis, and to determine if arsenic is being transported through trophic levels, the arsenic concentrations in members of a short food chain (soil-plant-meadow vole) were measured. Arsenic concentrations were higher in exposed organisms compared with those from a reference location. However, elevated concentrations of arsenic do not necessarily indicate impact, and consequently a biomonitoring study was undertaken to determine if there were sub-cellular effects of exposure in meadow voles (Microtus pennsylvanicus) as a consequence of arsenic exposure. In this work, adenosine triphosphate (ATP) and liver glutathione (GSH) levels were used as biomarkers of exposure and the frequency of red blood cell micronuclei (mono- and polychromatic) was used as a biomarker of effect. ATP results were not conclusive but there was a statistically significant relationship between a reduction of GSH in vole livers and increased liver arsenic concentrations. A statistically significant relationship was also observed between increased micronucleated monochromatic red blood cells in voles from arsenic contaminated sites compared to a background location. The results of the GSH and monochromatic red blood cell investigations suggest that there are possible sub-cellular effects on these voles as a consequence of dietary arsenic exposure. This is the first field study in which such effects have been observed in voles living near mine tailings.