Chronic exposure to lead (Pb) in livestock grazing in abandoned mining areas affects animal welfare and productivity, as well as represents a significant food safety risk. Here, we evaluate the physiological effects of Pb exposure in goats maintained under extensive farming conditions in a non-remediated mining area. We monitored blood, fecal, and milk Pb levels in two groups of goats, pregnant (n = 17) and lactating (n = 24), kept in different enclosures with high soil Pb concentrations (geometric means of 270 and 143 μg/g, respectively) in Sierra Madrona mining district (Spain). We also studied the influence of Pb exposure on the ability to mount a cellular immune response, and on oxidative stress and biochemical biomarkers measured in blood. Blood Pb concentration was higher in pregnant than in lactating goats, but this difference was not observed in fecal Pb concentration. Pb levels in feces and milk concentrations were correlated with those measured in blood, with 11% of milk samples showing Pb concentrations above the maximum level (ML) for Pb in raw milk established by the EU (0.02 μg/g wet weight). Animals with increased blood Pb levels showed reduced concentrations of retinol in plasma, but these Pb levels did not affect the cellular immune response. The stimulation of the cellular immune response in lactating goats was associated with an increase in blood Pb and calcium levels. The reproductive status and age of goats significantly affected several oxidative stress, antioxidants and plasma biochemistry variables. Goats grazing on soils contaminated by past Pb mining activities may be susceptible to detrimental health effects mediated by retinol deficiency. In view of the detected transfer of Pb through milk, special attention should be paid to the food safety of derived products (i.e. cheese).

Two releases from steam assisted gravity drainage (SAGD) wellheads occurred 3 yr apart. To track recovery of the affected areas, red‐backed voles were studied 1 and 4 yr later, using population estimates, hepatic detoxification effort, body condition, and tissue metal levels as bioindicators of site recovery. From years 1 to 4, higher ethoxyresorufin‐O‐deethylase induction was no longer evident, capture rate was lower, and body lead residues were no longer (inversely) correlated with body condition. Environ Toxicol Chem 2019;38:1542–1548. © 2019 SETAC

Two releases from steam assisted gravity drainage (SAGD) wellheads occurred 3 yr apart. To track recovery of the affected areas, red‐backed voles were studied 1 and 4 yr later, using population estimates, hepatic detoxification effort, body condition, and tissue metal levels as bioindicators of site recovery. From years 1 to 4, higher ethoxyresorufin‐O‐deethylase induction was no longer evident, capture rate was lower, and body lead residues were no longer (inversely) correlated with body condition. Environ Toxicol Chem 2019;38:1542–1548. © 2019 SETAC

Two releases from steam assisted gravity drainage (SAGD) wellheads occurred 3 yr apart. To track recovery of the affected areas, red‐backed voles were studied 1 and 4 yr later, using population estimates, hepatic detoxification effort, body condition, and tissue metal levels as bioindicators of site recovery. From years 1 to 4, higher ethoxyresorufin‐O‐deethylase induction was no longer evident, capture rate was lower, and body lead residues were no longer (inversely) correlated with body condition. Environ Toxicol Chem 2019;38:1542–1548. © 2019 SETAC

Non-ferrous metal mining is considered one of the largest sources of toxic metal released to the environment and may threaten ecosystems, notably biota. We explored how birds that inhabit non-ferrous metal mining sites are exposed to mercury, lead, and other trace elements by analyzing their feathers and verifying which factors may influence element concentrations in feathers. We sampled a total of 168 birds, representing 26 species, with different feeding habits and migration patterns in a non-polluted reference site and two historical metal mining areas: Almadén, which is considered one of the most heavily mercury-contaminated sites worldwide, and the Sierra Madrona mountains where lead has been mined since ancient times. The quantification of aluminum (Al), arsenic (As), barium (Ba), beryllium (Be), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), magnesium (Mg), manganese (Mn), molybdenum (Mo), nickel (Ni), lead (Pb), selenium (Se), thorium (Th), thallium (Tl), uranium (U), vanadium (V) and zinc (Zn) was performed by inductively coupled plasma mass spectrometry (ICP-MS). Feather analysis revealed contamination by Hg and Pb, in Almadén and Sierra Madrona, respectively. We found that granivorous birds had the lowest feather Hg levels compared to those found in omnivorous, insectivorous, and piscivorous species, whereas feather Pb was about twice as high in granivores and omnivores, than in insectivorous and piscivorous birds. We also found differences among study sites in 13 elements and confirmed the influence of feather age, migratory patterns of the birds, and external deposition of elements, on metal concentrations in the feathers. Our results highlight that despite the cessation of metal mining in the study areas, local avifauna are being exposed to Hg and Pb from abandoned mines and old tailings sites, indicating that appropriate measures are needed to protect biota from overexposure to these toxic metals.

Abstract Parasites are integral to ecosystem functioning yet often overlooked. Improved understanding of host–parasite associations is important, particularly for wide‐ranging species for which host range shifts and climate change could alter host–parasite interactions and their effects on ecosystem function. Among the most widely distributed mammals with diverse diets, gray wolves (Canis lupus) host parasites that are transmitted among canids and via prey species. Wolf–parasite associations may therefore influence the population dynamics and ecological functions of both wolves and their prey. Our goal was to identify large‐scale processes that shape host–parasite interactions across populations, with the wolf as a model organism. By compiling data from various studies, we examined the fecal prevalence of gastrointestinal parasites in six wolf populations from two continents in relation to wolf density, diet diversity, and other ecological conditions. As expected, we found that the fecal prevalence of parasites transmitted directly to wolves via contact with other canids or their excreta was positively associated with wolf density. Contrary to our expectations, the fecal prevalence of parasites transmitted via prey was negatively associated with prey diversity. We also found that parasite communities reflected landscape characteristics and specific prey items available to wolves. Several parasite taxa identified in this study, including hookworms and coccidian protozoans, can cause morbidity and mortality in canids, especially in pups, or in combination with other stressors. The density–prevalence relationship for parasites with simple life cycles may reflect a regulatory role of gastrointestinal parasites on wolf populations. Our result that fecal prevalence of parasites was lower in wolves with more diverse diets could provide insight into the mechanisms by which biodiversity may regulate disease. A diverse suite of predator–prey interactions could regulate the effects of parasitism on prey populations and mitigate the transmission of infectious agents, including zoonoses, spread via trophic interactions.

Chronic arsenic exposure is associated with a number of systemic diseases, including cardiovascular disease. Selenium has been shown to promote arsenic excretion from the body. We investigated if a high-selenium lentil diet has an effect on blood pressure and plasma lipid levels in an arsenic-exposed population by conducting a 6-month randomized controlled dietary intervention trial with 405 participants.

The development of anuran larvae from hatchling through metamorphosis is a particularly sensitive life stage that often is studied to assess adverse effects of water pollution, such as metal contamination. As an integral part of the food chain, high metal exposure and accumulation in developing anuran larvae may not only affect their survival but also pose a threat to secondary consumers. The presented work examines metal accumulation in wood frog tadpoles ( Lithobates sylvaticus ) before and after reaching metamorphic climax at emergence of the forelimbs. Metal levels were determined in whole tadpoles pre- and post-metamorphic climax in tadpole tissue excluding the stomach and intestines, as well as in water, via inductively coupled plasma-mass spectrometry. Wood frog tadpoles concentrated metals in their gut coil, with a rapid decline coincident with metamorphic climax. Tadpoles raised in a diluted bitumen-contaminated environment had higher levels of vanadium, molybdenum and cadmium, but not at levels expected to negatively impact development. In conclusion, metal accumulation in wood frog tadpoles varies greatly depending on developmental stage surrounding metamorphic climax. Metabolic changes and intestinal remodelling must be considered when studying pollutants in developing anuran larvae.

Hair cortisol has been demonstrated to reflect hypothalamic-pituitary-adrenal axis activity (including Cushing's disease and stress) in several species. We hypothesized that hair cortisol concentrations are increased in horses with pituitary pars intermedia dysfunction (PPID) compared with healthy adult horses and that this difference is magnified in the fall, when circulating adrenocorticotropin (ACTH) is generally the highest. Cortisol from hair collected using clippers with a #40 blade from the neck was compared between PPID horses and control horses over several months in the fall (August-December) and 1 mo in spring (May). Cortisol from hair at several sampling sites (neck, jugular furrow, sternum, and submandibular) were compared between PPID (n = 6) and control (n = 8) horses in May. Relationships between hair cortisol and ACTH were assessed in the fall. Hair cortisol when measured by weight was higher in PPID vs control horses in October and November (P ≤ 0.01) but not December (P = 0.15), May (P > 0.7), or August-September (P = 0.18). When normalized for hair length, hair cortisol was higher in PPID vs control horses in November (P = 0.0006), but not October or December (P ≥ 0.06). Hair cortisol concentrations did not differ between PPID and control horses from any collection site in May (P > 0.7). There were no consistent relationships between ACTH and hair cortisol concentrations in October, November, or December (P ≥ 0.05). These findings suggest that PPID horses have increased hair cortisol accumulation in the fall compared with control horses. Additional work is needed to clarify whether assessing cortisol per weight or per hair length is most relevant in the horse.

Abstract Two releases from steam assisted gravity drainage (SAGD) wellheads occurred 3 yr apart. To track recovery of the affected areas, red-backed voles were studied 1 and 4 yr later, using population estimates, hepatic detoxification effort, body condition, and tissue metal levels as bioindicators of site recovery. From years 1 to 4, higher ethoxyresorufin-O-deethylase induction was no longer evident, capture rate was lower, and body lead residues were no longer (inversely) correlated with body condition. Environ Toxicol Chem 2019;38:1542–1548. © 2019 SETAC Abstract

Industrial development and contaminant exposure may affect reproductive success and food quality for birds. Tree Swallows (Tachycineta bicolor (Vieillot, 1808)) nesting near oil sands development in northern Alberta (Canada) potentially experience elevated environmental stressors that could influence reproduction. We measured reproductive and growth endpoints in Tree Swallows, predicting reduced reproductive success and nestling growth near oil sands operations compared with reference sites. We also identified the invertebrate prey in the stomach contents of nestlings to understand variability in the diet and its potential effect on growth and survival of nestlings. From 2012 to 2015, clutch initiation varied among years but was not influenced by proximity to oil sands operations. Hatching and fledging success decreased in response to increased precipitation, regardless of location. Measurements of nestling growth reflected the variation associated with nestling sex and possibly asynchronous hatching. The composition of the nestling diet was significantly different; birds near oil sands development consumed Odonata, whereas birds at reference sites consumed Ephemeroptera. Nestlings from all sites consumed relatively high quantities of terrestrial insects. Our results demonstrate that factors such as weather conditions, diet, hatching order, and nestling sex are important when interpreting the potential effects of oil sands development on nest success and nestling growth.

Chronic arsenic (As) exposure is a major environmental threat to human health affecting >100 million people worldwide. Low blood selenium (Se) increases the risk of As-induced health problems. Our aim was to reduce As toxicity through a naturally Se-rich lentil diet. In a randomized, double-blind, placebo-control trial in Bangladesh, 405 participants chronically exposed to As were enrolled. The intervention arm (Se-group) consumed Se-rich lentils (55 μg Se/day); the control arm received lentils of similar nutrient profile except with low Se (1.5 μg Se/day). Anthropometric measurements, blood, urine and stool samples, were taken at baseline, 3 and 6 months; hair at baseline and 6 months after intervention. Morbidity data were collected fortnightly. Measurements included total As in all biological samples, As metabolites in urine, and total Se in blood and urine. Intervention with Se-rich lentils resulted in higher urinary As excretion (p = 0.001); increased body mass index (p ≤ 0.01), and lower incidence of asthma (p = 0.05) and allergy (p = 0.02) compared to the control group. The Se-group demonstrated increased excretion of urinary As metabolite, dimethylarsinic acid (DMA) at 6 months compared to control group (p = 0.008). Consuming Se-rich lentils can increase As excretion and improve the health indicators in the presence of continued As exposure.

Two releases from steam assisted gravity drainage (SAGD) wellheads occurred 3 yr apart. To track recovery of the affected areas, red-backed voles were studied 1 and 4 yr later, using population estimates, hepatic detoxification effort, body condition, and tissue metal levels as bioindicators of site recovery. From years 1 to 4, higher ethoxyresorufin-O-deethylase induction was no longer evident, capture rate was lower, and body lead residues were no longer (inversely) correlated with body condition. Environ Toxicol Chem 2019;38:1542-1548. (c) 2019 SETAC

This 6-month clinical trial tests whether high-selenium lentils, as a whole food solution, can improve the health of arsenic-exposed Bangladeshi villagers. The study entails 400 participants in two treatment groups. All participating households have tubewell water containing >= 100 mu g L-1, but over 50% are >250 mu g L-1. In this double-blind study, one group is daily consuming high-selenium lentils from the Canadian prairies, the other, low-selenium lentils grown in another ecozone. At the onset, mid-term, and end of the trial, samples (blood, urine, stool, hair) are collected, and health examinations include testing lung inflammation, body weight and blood pressure. The major outcome will be arsenic excretion in urine and feces, and arsenic deposition in hair. Secondary outcomes also include antioxidant status, and blood lipid profile.

Mining in the Athabasca Oil Sands Region (AOSR) has contributed extensively to increased exposure of wildlife to naturally occurring polycyclic aromatic compounds (PACs), yet little is known about the toxicity of PACs to wildlife in this region. We identified reproductive and developmental changes in tree swallows (Tachycineta bicolor) breeding in close proximity to mining-related activities in the AOSR, and determined these changes in relation to the birds' exposure and accumulation of 41 PACs (parent-, alkylated-PAHs), dibenzothiophenes (DBTs; previously published), diet (carbon (δ13C), nitrogen (δ15N)), volatile organic compounds, and weather variables. Tree swallow pairs (N = 43) were compared among mining-related (OS1, OS2) and reference (REF1, REF2) sites. At OS2, clutch initiation was slightly advanced (2012) but reproductive success (65%) was much lower than at the other sites (≥ 79%). Fledgling production by each pair was influenced by the timing of clutch initiation (years combined); in a highly inclement brood rearing period (2013), additional influences included the nestlings' exposure to ΣDBTs, accumulation of C1-naphthalene, the trophic position of the prey in their diet (δ15N), and record-breaking rainfall. Nestlings at OS2 were significantly lighter at day (d) 9 and d14, and in poorer body condition (d9). Nestling body mass was influenced by multiple stressors that varied by site: mass of younger nestlings (d9) was related to dietary source (δ13C; e.g., wetlands, terrestrial fields), exposure and/or accumulation of C1-phenanthrenes, C2-fluorenes, Σalkyl-PAHs and ΣDBTs, while for older nestlings (d14), body mass was related to sex, hatch date and/or rainfall during brood rearing. The swallows' exposure and accumulation of parent-PACs, alkyl-PACs and DBTs, the timing of hatching, their diet and exposure to highly inclement rains, contributed to their reproductive and developmental changes.

The objective of this study was to design an enclosure suitable for studying the ecotoxicological effects of vehicle emissions on groups of wild birds without compromising welfare. Two, adjacent enclosures sheltered from sunlight, wind and rain, were bird-proofed and wrapped with thick polyethylene sheeting. Emissions were directed into the treatment enclosure from the exhaust of a light-duty gasoline truck, using flexible, heat-proof pipe, with joins sealed to prevent leakage. During active exposure, the engine was idled for 5 h/day, 6 days/week for 4 weeks. Fans maintained positive pressure (controls) and negative pressure (treatment), preventing cross-contamination of enclosures and protecting investigators. Four sets of passive, badge-type samplers were distributed across each enclosure, measuring nitrogen dioxide, sulfur dioxide and volatile organic compounds (NO2, SO2 and VOCs, respectively), and were complemented by active monitors measuring VOCs and particulate matter (2.5 mu m diameter, PM2.5). We found that the concentrations of NO2, SO2 and PM2.5 were not different between treatment and control enclosures. Volatile organic compounds (e.g. benzene, toluene, ethylbenzene and xylenes) were approximately six times higher in the treatment enclosure than control (13.23 and 2.13 mu g m(-1), respectively). In conclusion, this represents a successful, practical design for studying the effects of sub-chronic to chronic exposure to realistic mixtures of vehicle exhaust contaminants, in groups of birds. Recommended modifications for future research include a chassis dynamometer (vehicle treadmill), to better replicate driving conditions including acceleration and deceleration.

In the Canadian Athabasca Oil Sands Region (AOSR), nestling tree swallows (Tachycineta bicolor) raised near mining-related activities accumulated greater concentrations of polycyclic aromatic compounds (PACs) that contributed to their poorer condition, growth, and reproductive success. Here, we report changes in thyroid function of the same 14 day old (do) nestlings (N ≤ 68) at these mining-related sites (OS1, OS2) compared to reference nestlings (REF1), and in relation to multiple environmental stressors that influence avian thyroid function. Thyroid function was compromised for OS1 nestlings but generally comparable between OS2 and REF1 chicks. In 2012, circulating total triiodothyronine (TT3) and thyroxine (TT4) were similar among all nestlings. The OS1 chicks had more active thyroid glands based on histological endpoints. Hepatic T4 outer-ring deiodinase (T4-ORD) activity was suppressed in OS1 and OS2 chicks. Despite inter-annual differences, OS1 chicks continued experiencing compromised thyroid function with significantly higher circulating TT4 and more active thyroid glands in 2013. The OS2 chicks had less active thyroid glands, which conceivably contributed to their suppressed growth (previously reported) relative to the heavier OS1 nestlings with more active thyroid glands. Thyroid gland activity was more influenced by the chicks' accumulation of (muscle), than exposure (feces) to naphthalene, C2-naphthalenes, and C1-fluorenes. Of four major volatile organic contaminants, sulfur dioxide (SO2) primarily influenced thyroid gland activity and structure, supporting previous findings with captive birds. When collectively considering environmental-thyroidal stressors, chicks had a greater thyroidal response when they experienced colder temperatures, accumulated more C2-naphthalenes, and consumed aquatic-emerging insects with higher PAC burdens than terrestrial insects (carbon (δ13C)). We hypothesize that the more active thyroid glands and higher circulating TT4 of the OS1 chicks supported their growth and survival despite having the highest PAC burdens, whereas the lack of thyroid response in the OS2 chicks combined with high PAC burdens, contributed to their smaller size, poorer condition and poorer survival.

Hair analysis is emerging as a popular tool to examine stress and reproduction hormone levels in wild mammals. The reliability of this approach, however, depends on an understanding of steroid hormone incorporation into hair as well as appropriate validations. We reviewed studies that have examined steroid hormones in wildlife hair with the goal of summarizing the analytical, physiological, and biological evidence that this approach is meaningful. Accordingly, we differentiated among validations aimed at evaluating the reliability of the analytical method versus those designed to assess whether hormone levels in hair reflect physiologically meaningful processes in the target species. Our literature survey revealed that endogenous steroids have been examined in hair from 40 species of nonhuman animals across seven mammalian classes. Although the majority (85%) of 72 studies reported analytical validations of the method, physiological validations have only been reported for five species. Moreover, results of physiological validations were inconsistent among studies. This highlights the need for further research, carefully designed to differentiate between the multiple purported models of steroid incorporation into hair in species with different types of hair and different hair growth patterns. To complement our review of published studies, we present new data supporting a positive relationship between levels of the steroid, cortisol, in hair and blood across eight mammalian species. In addition, we present novel results from a laboratory‐based study showing variable hair growth in genetically identical laboratory mice that were kept under controlled conditions. Synthesis and applications. Collectively, this Review reveals substantial progress towards the validation of stress hormone assays in hair from a variety of wildlife species. Further validations of reproductive steroids, combined with appropriate physiological validations, would expand the potential applications of hair analyses in wildlife research. As a key example, physiological data can provide mechanistic insights into species’ responses to change and may therefore contribute to conservation planning.

BACKGROUNDFaba bean (Vicia faba) vicine and convicine (V-C) aglycones (divicine and isouramil respectively) provoke an acute hemolytic anemia called favism in individuals with a glucose-6-phosphate dehydrogenase (G6PD) enzyme defect in their red blood cells. Geneticists/plant breeders are working with faba bean to decrease V-C levels to improve public acceptance of this high-protein pulse crop. Here, we present a fast and simple ex vivo in vitro bioassay for V-C toxicity testing of faba bean or faba bean food products.RESULTSWe have shown that 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU)-treated (i.e., sensitized) normal red blood cells, like G6PD-defective blood, displayed (i) continuous glutathione (GSH) depletion with no regeneration as incubation time and the dose of aglycones increased, (ii) progressive accumulation of denatured hemoglobin products into high molecular weight (HMW) proteins with increased aglycone dose, (iii) both band 3 membrane proteins and hemichromes, in HMW protein aggregates. We have also demonstrated that sensitized red blood cells can effectively differentiate various levels of toxicity among faba bean varieties through the two hemolysis biomarkers: GSH depletion and HMW clumping.CONCLUSIONBCNU-sensitized red blood cells provide an ideal model for favism blood, to assess and compare the toxicity of faba bean varieties and their food products. © 2018 Society of Chemical Industry.