Polycyclic aromatic hydrocarbons in blood related to lower body mass in common loons

Microbead-Beating Extraction of Polycyclic Aromatic Compounds from Seabird Plasma and Whole Blood

Seabirds are widely regarded as an invaluable bioindicator of environmental health. Matrices including eggs and feathers have been used as non-lethal means to assess contaminant burdens. We have developed a new approach for extraction of polycyclic aromatic compounds (PACs) from seabird plasma and serum based on automated microbead-beating homogenization and extraction. Commercially available bovine serum and plasma were purposely fortified with a suite of PACs separately at three dosing levels, placed inside a custom-made stainless-steel tube containing ceramic microbeads, and subjected to an extraction process using a Precellys tissue homogenizer. Tubes were shaken forcefully in three-dimensions, facilitating high mass-transfer of PACs from the matrix into the hexane extraction solvent. The accuracy of the method ranged from 55 to 120% and limits of detection and quantitation ranged from 0.1 to 8 and 0.2 to 27 pg/μL, respectively. The method exhibited good repeatability with both inter- and intra-day repeatability < 30%. The developed method represents an effective and efficient approach to extraction of PACs from important biological matrices.

Legacy and emerging contaminants in flamingos' chicks' blood from the Ebro Delta Natural Park

The Ebro Delta is a wetland of international importance for waterbird conservation but severally affected by intensive agriculture, toxic waste discharges from a past chloro-alkali industry and affluence of tourism. The discharge of contaminants associated to these activities pose waterbirds breeding in the Ebro Delta at risk. The aim of this study is to evaluate the exposure of 91 emerging and legacy micropollutants in flamingo chicks (Phoenicopterus roseus), an emblematic species of the area. Fifty chicks of 45-60 days were captured, biometric parameters measured and whole blood collected. Compounds analyzed included perfluoroalkyl substances (PFASs), pharmaceuticals, organophosphate esters (OPEs), in-use pesticides, polychlorinated biphenyls (PCBs), organochlorine pesticides (OCs), and polycyclic aromatic hydrocarbons (PAHs). The results indicate a multi-exposure of flamingo's chicks from a very young age. PFASs were the most ubiquitous compounds with ∑PFASs ranging from 9.34 to 576 ng/mL, being PFOA, PFOS and PFHxS detected in all samples. ∑PAHs ranged from 0.19 to 423 ng/mL, ∑PCBs from 0.5 to 15.6 ng/mL and ∑OCs from 1.35 to 37.8 ng/mL. Pharmaceuticals, OPEs and in-use pesticides were not detected. The flamingo's filtering behavior on mud and maternal ovo-transference are the more likely routes of exposure of organic micropollutants to flamingos' chicks. The reported levels of micropollutants were not associated with any alteration in the body condition of chicks. This is the first study to describe flamingos chicks' exposure to multiple contaminants, highlighting the importance of biomonitoring for wildlife conservation and biodiversity preservation.

Effects of diluted bitumen exposure on the survival, physiology, and behaviour of zebra finches (Taeniopygia guttata)

Diluted bitumen (dilbit) is an unconventional crude petroleum increasingly being extracted and transported to market by pipeline and tanker. Despite the transport of dilbit through terrestrial, aquatic, and coastal habitat important to diverse bird fauna, toxicity data are currently only available for fish and invertebrates. We used the zebra finch (Taeniopygia guttata) as a tractable, avian model system to investigate exposure effects of lightly weathered Cold Lake blend dilbit on survival, tissue residue, and a range of physiological and behavioural endpoints. Birds were exposed via oral gavage over 14-days with dosages of 0, 2, 4, 6, 8, 10, or 12 mL dilbit/kg bw/day. We identified an LD₅₀ of 9.4 mL/kg/d dilbit, with complete mortality at 12 mL/kg/d. Mortality was associated with mass loss, external oiling, decreased pectoral and heart mass, and increased liver mass. Hepatic ethoxyresorufin-O-deethylase activity (EROD) was elevated in all dilbit-dosed birds compared with controls but there was limited evidence of sublethal effects of dilbit on physiological endpoints at doses < 10 mL/kg/d (hematocrit, hemoglobin, total antioxidants, and reactive oxygen metabolites). Dilbit exposure affected behavior, with more dilbit-treated birds foraging away from the feeder, more birds sleeping or idle at low dilbit doses, and fewer birds huddling together at high dilbit doses. Naphthalene, dibenzothiophene, and their alkylated congeners in particular (e.g. C2-napthalene and C2-dibenzothiophene) accumulated in the liver at greater concentrations in dilbit-treated birds compared to controls. Although directly comparable studies in the zebra finch are limited, our mortality data suggest that dilbit is more toxic than the well-studied MC252 conventional light crude oil with this exposure regime. A lack of overt sublethal effects at lower doses, but effects on body mass and composition, behaviour, high mortality, and elevated PAC residue at doses ≥ 10 mL/kg/d suggest a threshold effect.

Organochlorine pesticides, polycyclic aromatic hydrocarbons, metals and metalloids in microplastics found in regurgitated pellets of black vulture from Campeche, Mexico

Plastics are produced by the millions of tons worldwide each year, with their final deposition in landfills (LFs). Plastics deposited in LFs can fragment over time, giving rise to mesoplastics and later to microplastics (MPs), in which toxic chemicals such as heavy metals, organochlorine pesticides, and polycyclic aromatic hydrocarbons can adhere. MPs can be vectors for the exposure to pollutants of black vultures (Coragyps atratus) due to feeding in LFs, resulting in accidental ingestion of MPs. It is also possible that MPs can adsorb pollutants from vultures during the digestion process. The aim of this study was to estimate the risk of black vulture exposure to MPs, heavy metals (HMs), organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs). Fifty-eight black vulture pellets were collected at the Campeche LF during 2019 (n = 24) and 2020 (n = 34). The pellets, on average, had an MP load per pellet of 6.7 ± 5.8 MPs/total pellets. The greatest abundance of MPs was detected in 2019, with 225 particles in total. The concentrations of Cd, Pb, Cu, Cr, Hg, As, and Al were detected in the MPs, with the greatest average concentration of 35.59 ± 32.39 μg·g^-1 (2019) and 15.82 ± 17.47 μg·g^-1 (2020) for Al. In 2020, ∑endosulfans were present in all MPs at 0.97 ± 1.47 ng·g^-1. Among the PAHs, 15 of the 16 compounds indicated as priorities by the US EPA were quantified. The compound with the greatest total concentration for both years was acenaphthylene (3 rings), with 10.51 ± 7.88 ng·g^-1 (2019) and 10.61 ± 18 ng·g^-1 (2020). More research is needed regarding the origin of the contaminants detected in the MPs extracted from the pellets, since the contaminants may come from the environment or possibly from the digestion processes in the stomach of avian raptors and scavengers.

A review of the toxicology of oil in vertebrates: what we have learned following the Deepwater Horizon oil spill

In the wake of the Deepwater Horizon (DWH) oil spill, a number of government agencies, academic institutions, consultants, and nonprofit organizations conducted lab- and field-based research to understand the toxic effects of the oil. Lab testing was performed with a variety of fish, birds, turtles, and vertebrate cell lines (as well as invertebrates); field biologists conducted observations on fish, birds, turtles, and marine mammals; and epidemiologists carried out observational studies in humans. Eight years after the spill, scientists and resource managers held a workshop to summarize the similarities and differences in the effects of DWH oil on vertebrate taxa and to identify remaining gaps in our understanding of oil toxicity in wildlife and humans, building upon the cross-taxonomic synthesis initiated during the Natural Resource Damage Assessment. Across the studies, consistency was found in the types of toxic response observed in the different organisms. Impairment of stress responses and adrenal gland function, cardiotoxicity, immune system dysfunction, disruption of blood cells and their function, effects on locomotion, and oxidative damage were observed across taxa. This consistency suggests conservation in the mechanisms of action and disease pathogenesis. From a toxicological perspective, a logical progression of impacts was noted: from molecular and cellular effects that manifest as organ dysfunction, to systemic effects that compromise fitness, growth, reproductive potential, and survival. From a clinical perspective, adverse health effects from DWH oil spill exposure formed a suite of signs/symptomatic responses that at the highest doses/concentrations resulted in multi-organ system failure.

Nest survival of Seaside Sparrows (Ammospiza maritima) in the wake of the Deepwater Horizon oil spill

In 2010, the Deepwater Horizon oil spill released an estimated 4.9 million barrels of oil into the Gulf of Mexico, damaging coastal ecosystems. Seaside Sparrows (Ammospiza maritima)-a year-round resident of Gulf Coast salt marshes-were exposed to oil, as shown by published isotopic and molecular analyses, but fitness consequences have not been clarified. We monitored nests around two bays in Plaquemines Parish, Louisiana, USA from 2012-2017 to assess possible impacts on the nesting biology of Seaside Sparrows. A majority of nests failed (76% of known-fate nests, N = 252 nests, 3521 exposure-days) during our study, and predation was the main cause of nest failure (~91% of failed nests). Logistic exposure analysis revealed that daily nest survival rate: (1) was greater at nests with denser vegetation at nest height, (2) was higher in the more sheltered bay we studied, (3) decreased over the course of the breeding season in each year, and (4) was not correlated with either sediment polycyclic aromatic hydrocarbon concentrations or estimated predator abundance during the years for which we had those data. Although the Deepwater Horizon spill impacted other aspects of Seaside Sparrow ecology, we found no definitive effect of initial oiling or oiled sediment on nest survival during 2012-2017. Because predation was the overwhelming cause of nest failure in our study, additional work on these communities is needed to fully understand demographic and ecological impacts of storms, oil spills, other pollutants, and sea-level rise on Seaside Sparrows and their predators.

Revising the marine range of the endangered black-capped petrel Pterodroma hasitata: occurrence in the northern Gulf of Mexico and exposure to conservation threats

The black-capped petrel Pterodroma hasitata is an Endangered seabird endemic to the western North Atlantic. Although estimated at ~1000 breeding pairs, only ~100 nests have been located at 2 sites in Haiti and 3 sites in the Dominican Republic. At sea, the species primarily occupies waters of the western Gulf Stream in the Atlantic and the Caribbean Sea. Due to limited data, there is currently no consensus on the geographic marine range of the species although no current proposed ranges include the Gulf of Mexico. Here, we report on observations of black-capped petrels during 2 vessel-based survey efforts throughout the northern Gulf of Mexico from 2010-2011 and 2017-2019. During 558 d and ~54700 km of surveys, we tallied 40 black-capped petrels. Most observations occurred in the eastern Gulf, although birds were observed over much of the east-west and north-south footprint of the survey area. Predictive models indicated that habitat suitability for black-capped petrels was highest in areas associated with dynamic waters of the Loop Current. We used the extent of occurrence and area of occupancy concepts to delimit the geographic range of the species within the northern Gulf. We suggest that the marine range for black-capped petrels be modified to include the northern Gulf of Mexico, recognizing that distribution may be more clumped in the eastern Gulf and that occurrence in the southern Gulf remains unknown due to a lack of surveys there. To date, however, it remains unclear which nesting areas are linked to the Gulf of Mexico.

Effects of petroleum exposure on birds: A review

Birds are vulnerable to petroleum pollution, and exposure has a range of negative effects resulting from plumage fouling, systemic toxicity, and embryotoxicity. Recent research has not been synthesized since Leighton's 1993 review despite the continued discharge of conventional petroleum, including high-volume oil spills and chronic oil pollution, as well as the emergence of understudied unconventional crude oil types. To address this, we reviewed the individual-level effects of crude oil and refined fuel exposure in avifauna with peer-reviewed articles published 1993-2020 to provide a critical synthesis of the state of the science. We also sought to answer how unconventional crude petroleum effects compare with conventional crude oil. Relevant knowledge gaps and research challenges were identified. The resulting review examines avian exposure to petroleum and synthesizes advances regarding the physical effects of oil hydrocarbons on feather structure and function, as well the toxic effects of inhaled or ingested oil, embryotoxicity, and how exposure affects broader scale endpoints related to behavior, reproduction, and survival. Another outcome of the review was the knowledge gaps and challenges identified. The first finding was a paucity of oil ingestion rate estimates in birds. Characterizing environmentally realistic exposure and ingestion rates is a higher research priority than additional conventional oral dosing experiments. Second, there is an absence of toxicity data for unconventional crude petroleum. Although the effects of air and water contamination in the Canadian oil sands region have received attention, toxicity data for direct exposure to unrefined bitumen produced there in high volumes and other such unconventional oil types are needed. Third, we encountered barriers to the interpretation, replication, broad relevance, and comparability of studies. We therefore propose best practices and promising technological advancements for researchers. This review consolidates our understanding of petroleum's effects on birds and points a way forward for researchers and resource managers.

Estimation of native and alkylated polycyclic aromatic hydrocarbons (PAHs) in seabirds from the south coast of the Baltic Sea

Native and alkylated polycyclic aromatic hydrocarbons (PAHs) were examined in the muscle, liver, kidneys, and lungs of greater scaup (Aythya marila) and great crested grebe (Podiceps cristatus). Both species showed differences in distribution and profiles among the tissues. The highest ƩPAH concentrations were in the scaup lungs and the grebe kidneys (20 and 19 ng g^-1 wet weight, respectively). Alkylated derivatives were in the range of 61 to 77% of ΣPAHs in both species. Differences in PAH profiles between birds, analyzed by PCA, were probably results of metabolic capability, not various diet. In comparison to available data from other regions of the world, PAH levels in investigated species are relatively low and do not pose a threat to birds themselves.

Polycyclic aromatic compounds (PACs) and trace elements in four marine bird species from northern Canada in a region of natural marine oil and gas seeps

There is a growing understanding of how oil pollution can affect aquatic ecosystems, including physical and chemical effects. One of the biggest challenges with detecting the effects of oil-related contaminants on biota from resource development is understanding the background levels and potential effects of the exposure of biota to contaminants from various natural and anthropogenic sources prior to large scale oil and gas operations. Seabirds are effective indicators of pollution, and can be useful for tracking oil-related contaminants in the marine environment. We sampled four seabird species (black guillemot, Cepphus grylle; thick-billed murre, Uria lomvia; black-legged kittiwake, Rissa tridactyla; and northern fulmar, Fulmarus glacialis) in the Baffin Bay-Davis Strait region of the Northwest Atlantic and Arctic oceans, an area where natural oil and gas seeps are present but lacking any large-scale oil and gas projects. We found detectable levels of PACs and several trace elements in all species examined. Alkylated PAC levels were higher than parent compounds in all four seabird species examined, with fulmars and murres having the highest levels detected; mean hepatic concentrations of ∑₁₆PAC were 99.05, 46.42, 12.78 and 9.57 ng/g lw, respectively, for guillemots, murres, fulmars and kittiwakes. Overall, PAC concentrations in the seabird species examined were similar to PAC concentrations measured in other bird species in regions with more industrialization. These findings provide data which can be used to assess the current oil-related contaminant exposure of biota in the region. As well, they provide background levels for the region at a time when shipping activity is relatively low, which can used for future comparisons following expected increases in shipping and oil and gas activities in the region.

A First Comprehensive Baseline of Hydrocarbon Pollution in Gulf of Mexico Fishes

Despite over seven decades of production and hundreds of oil spills per year, there were no comprehensive baselines for petroleum contamination in the Gulf of Mexico (GoM) prior to this study. Subsequent to the 2010 Deepwater Horizon (DWH) spill, we implemented Gulf-wide fish surveys extending over seven years (2011–2018). A total of 2,503 fishes, comprised of 91 species, were sampled from 359 locations and evaluated for biliary polycyclic aromatic hydrocarbon (PAH) concentrations. The northern GoM had significantly higher total biliary PAH concentrations than the West Florida Shelf, and coastal regions off Mexico and Cuba. The highest concentrations of biliary PAH metabolites occurred in Yellowfin Tuna (Thunnus albacares), Golden Tilefish (Lopholatilus chamaeleonticeps), and Red Drum (Sciaenops ocellatus). Conversely, biliary PAH concentrations were relatively low for most other species including economically important snappers and groupers. While oil contamination in most demersal species in the north central GoM declined in the first few years following DWH, more recent increases in exposure to PAHs in some species suggest a complex interaction between multiple input sources and possible re-suspension or bioturbation of oil-contaminated sediments. This study provides the most comprehensive baselines of PAH exposure in fishes ever conducted for a large marine ecosystem.

An investigation of physiological effects of the Deepwater Horizon oil spill on a long-distance migratory seabird, the northern gannet

Exposure to oil can have long-term impacts on migratory birds. Following the 2010 Deepwater Horizon blowout in the Gulf of Mexico (GOM), we investigated potential impacts of oil exposure on a population of northern gannets (Morus bassanus) that breed on Bonaventure Island (Québec, Canada) and winter in GOM and along the U.S. Atlantic coast (AC). Blood and feather samples were collected from adults previously equipped with geolocators to determine wintering locations. Parent and alkylated polycyclic aromatic hydrocarbons (PAHs); trace metals; stable isotopes of carbon, nitrogen, and hydrogen; and immune, thyroid, steroid, retinoid, and genetic endpoints were measured. PAH and trace metal concentrations did not differ between gannets using different wintering sites. Feather stable isotope values varied significantly between birds from different wintering locations. Gannets wintering in GOM showed higher feather corticosterone and plasma thyroid hormone levels, which may indicate increased energetic demands and/or greater exposure to environmental stressors.

Oiling of American white pelicans, common loons, and northern gannets in the winter following the Deepwater Horizon (MC252) oil spill

The Natural Resource Damage Assessment and Restoration Trustees for the Deepwater Horizon oil spill assessed the external oiling of migratory bird species dependent on open water in the Gulf of Mexico following the aforementioned spill. The assessment was designed to evaluate birds that use open water during the winter within 40 km of the Gulf shoreline. We focused on the American white pelican (Pelecanus erythrorhynchos), common loon (Gavia immer), and northern gannet (Morus bassanus). Point counts (pelican, loon) or strip transects (gannet) were used and each target species was assessed for oiling (unoiled, trace, light, moderate, or heavy amounts) and photographed. Due to distance at sighting and/or poor visibility, not all visible birds were assessed. The percentage of birds oiled varied by species, with the common loon being the highest (23.6%), followed by American white pelican (16.9%), and northern gannet (6.9%). Most of the American white pelicans and common loons had trace (83% and 72%, respectively) or light levels (11% and 24%, respectively) of oiling. The northern gannet had just trace levels of oiling. Some pelicans (6%) and loons (4%) had moderate amounts of oiling. Based on expert derived-mortality estimates and our estimates of oil exposure, we used Monte Carlo simulations to predict expected decreases of 2.5%, 4%, and 11% in the observed population for the northern gannet, American white pelican, and common loon, respectively. While these values are underestimates of the true values given the long time lag (10-12 months) between the oil spill and the assessment, these data represent some of the few estimates of exposure for these species and describe minimum risk estimates to these species.

Chronic PAH exposures and associated declines in fish health indices observed for ten grouper species in the Gulf of Mexico

Ten grouper species grouper (n = 584) were collected throughout the Gulf of Mexico (GoM) from 2011 through 2017 to provide information on hepatobiliary polycyclic aromatic hydrocarbon (PAH) concentrations in the aftermath of the Deepwater Horizon (DWH) oil spill. Liver and bile samples were analyzed for PAHs and their metabolites using triple quadrupole mass spectrometry (GC/MS/MS) and high-performance liquid chromatography with fluorescence detection (HPLC-F), respectively. Data were compared among species and sub-regions of the GoM to understand spatiotemporal exposure dynamics in these economically and ecologically important species. Significant differences in the composition and concentrations of PAHs were detected spatially, over time and by species. The West Florida Shelf, Cuba coast and the Yucatan Shelf had a greater proportion of the pyrogenic PAHs in their livers than the other regions likely due to non-oil industry related sources (e.g., marine vessel traffic) in the regional composition profiles. Mean liver PAH concentrations were highest in the north central region of the GoM where DWH occurred. Biliary PAH concentrations and health indicator biometrics initially decrease during the first three years following the DWH oil spill but significantly increased thereafter. Increased exposures are likely explained by the resuspension of residual DWH oil as well as continued inputs from natural (e.g., seeps) sources and other anthropogenically derived sources (e.g., riverine runoff, other oil spills, and leaking oil and gas infrastructure). The increasing trend in PAH concentrations in the bile and liver of grouper species in the north central region of the GoM post-DWH suggest continued chronic exposures, however the critical stage at which permanent, irreparable damage may occur is unknown. Long-term monitoring of PAH levels and associated fish health biomarkers is necessary to evaluate impacts of chronic exposures, particularly in regions subject to intensive oil extraction activities.

Restoration of common loons following the North Cape Oil Spill, Rhode Island, USA

Oil spills are a widespread problem in the marine environment and can have extensive acute and chronic adverse impacts to resident and migratory biota. On 19 January 1996, the North Cape oil tanker caught fire and grounded on the coast of Rhode Island resulting in the spill of 828,000 gal (3134 metric tonnes) of home heating oil. It resulted in the estimated death of nearly 2300 birds, including a projected 402 common loons (Gavia immer) and 12 red-throated loons (Gavia stellata). Based on existing demographic data, a resource equivalency analysis (REA) calculated that the total loss, as measured through dead adults and their foregone young over their expected lifetimes, was 2920 discounted loon-years. To generate compensatory loon years, it was initially estimated that 25 common loon nests would need protection from development for 100 years. Following a $3 million settlement with the parties responsible for the spill, we conducted surveys to identify the highest quality breeding loon habitat for protection. Monitoring efforts included 184 loon territories from 2000 to 2009, representing 866 loon territory-years on 70 lakes in four regions of Maine. To evaluate restoration effectiveness, an updated REA was conducted using productivity data collected from these surveys. Results from the updated REA indicated that were these site-specific data available when the REA was originally generated, 70 nests would have been required to offset the lost loon-years - this project permitted the protection of 119 nests. Future REAs should incorporate site specific productivity data whenever possible to most accurately scale restoration to injury. Ranking lake habitat quality further optimizes restoration effectiveness. Our results indicate breeding success was highest on 24-81 ha lakes and that emphasizing protection of lakes with loon territories in this size class is optimal. Our results demonstrate a need for site-specific restoration plans to achieve the greatest restoration benefits.

Associations Between Chronic Exposure to Polycyclic Aromatic Hydrocarbons and Health Indices in Gulf of Mexico Tilefish (Lopholatilus chamaeleonticeps) Post Deepwater Horizon

A time series of polycyclic aromatic hydrocarbon (PAH) data was collected for Gulf of Mexico demersal fishes in the years following the Deepwater Horizon oil spill (2012-2017). Tilefish (Lopholatilus chamaeleonticeps) were sampled via demersal longline at repeat stations in the northern Gulf of Mexico in 2012 to 2015 and 2017. Bile samples (n = 256) were analyzed via high-performance liquid chromatography with fluorescence detection for PAH metabolites as a biomarker of exposure to PAHs. Liver tissues (n = 230) were analyzed for accumulation of PAHs and alkylated homologs via quick, easy, cheap, effective, rugged, and safe (QuEChERS) extractions and gas chromatography-tandem mass spectrometry quantification. Over the 6-yr time series, exposure to petrogenic PAHs increased by an average of 178%, correlating with an average 22% decline in Fulton's condition factor. The decline in Fulton's condition factor was positively correlated with a 53% decline in percentage of liver lipid. There was no accumulation of PAHs in liver tissue over time. Together, these results suggest that increasing and chronic PAH exposure and metabolism may be taxing the energy budgets of tilefish, particularly adult females, with potentially negative impacts on fitness. Environ Toxicol Chem 2019;38:2659-2671. © 2019 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

Oil Spills and Human Health: Contributions of the Gulf of Mexico Research Initiative

The Gulf of Mexico Research Initiative (GoMRI) was established in 2010 with $500 million in funding provided by British Petroleum over a 10-year period to support research on the impacts of the Deepwater Horizon oil spill and recovery. Contributions of the GoMRI program to date focused on human health are presented in more than 32 peer-reviewed papers published between 2011 and May 2019. Primary findings from review of these papers are (i) the large quantity of dispersants used in the oil cleanup have been associated with human health concerns, including through obesogenicity, toxicity, and illnesses from aerosolization of the agents; (ii) oil contamination has been associated with potential for increases in harmful algal blooms and numbers of pathogenic Vibrio bacteria in oil-impacted waters; and (iii) members of Gulf communities who are heavily reliant upon natural resources for their livelihoods were found to be vulnerable to high levels of life disruptions and institutional distrust. Positive correlations include a finding that a high level of community attachment was beneficial for recovery. Actions taken to improve disaster response and reduce stress-associated health effects could lessen negative impacts of similar disasters in the future. Furthermore, GoMRI has supported annual conferences beginning in 2013 at which informative human health-related presentations have been made. Based on this review, it is recommended that the Oil Pollution Act of 1990 be updated to include enhanced funding for oil spill impacts to human health.

Hepatobiliary Analyses Suggest Chronic PAH Exposure in Hakes (Urophycis spp.) Following the Deepwater Horizon Oil Spill

Prior to the Deepwater Horizon oil spill, we lacked a comprehensive baseline of oil contamination in the Gulf of Mexico's sediments, water column, and biota. Gaps in prespill knowledge limit our ability to determine the aftereffects of the Deepwater Horizon blowout or prepare to mitigate similar impacts during future oil spill disasters. We examined spatiotemporal differences in exposure to and metabolism of polycyclic aromatic hydrocarbons (PAHs) in 2 hake species (Urophycis spp.) to establish a current baseline for these ecologically important, abundant, and at-risk demersal fishes. Gulf hake (Urophycis cirrata) and southern hake (Urophycis floridana) were collected throughout the Gulf of Mexico during extensive longline surveys from 2012 to 2015. Analyses of biliary PAH metabolites and liver PAH concentrations provided evidence of exposures to di- and tricyclic compounds, with the highest concentrations measured in the northern Gulf of Mexico. Species-specific differences were not detected, but temporal trends observed in biliary PAHs suggest a decrease in acute exposures, whereas increasing liver PAHs suggest chronic exposures marked by greater assimilation than metabolism rates. To our knowledge, the present study provides the first multitissue contaminant analyses, as well as the most exhaustive biometric analyses, for both gulf and southern hakes. Though sources of exposure are complex because of multiple natural and anthropogenic PAH inputs, these results will facilitate the development of much needed health metrics for Gulf of Mexico benthos. Environ Toxicol Chem 2019;38:2740-2749. © 2019 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

Assessment of Shorebird Migratory Fueling Physiology and Departure Timing in Relation to Polycyclic Aromatic Hydrocarbon Contamination in the Gulf of Mexico

Shorebirds depend on staging sites in the Gulf of Mexico that are frequently subject to pollution by oil and its toxic constituents, polycyclic aromatic hydrocarbons (PAHs). It was hypothesized that PAH contamination lowers staging site quality for migratory shorebirds, with consequences for fueling and departure timing. Sediment total PAH concentrations were measured at six staging sites along the Texas and Louisiana Gulf Coast. Sites in Louisiana were expected to have higher total PAH concentrations as they were more heavily impacted by the Deepwater Horizon oil spill. From 2015 to 2017, 165 Sanderling ( Calidris alba) and 55 Red knots ( C. canutus) were captured at these same sites during their northward migration (late April to mid May). Mass, body morphometrics, and plasma metabolite measurements were taken to determine fuel loads and fueling rates, and a subset of birds (120 Sanderling and 39 Red knots) received a coded radio tag to determine departure dates using the Motus telemetry array. Compared to Texas sites, sediment in Louisiana had higher total PAH concentrations, dominated by heavier 6 ring indeno[1,2,3- cd]pyrene (48%). Plasma metabolite profiles suggested that fueling rates for Sanderling, but not Red knots, tended to be lower in Louisiana, and both species departed later than the study average from Louisiana. However, multiple factors, including migration patterns, food supply, and other contaminants, also likely influenced fueling and departures. PAH contamination in the Gulf of Mexico remains an ongoing issue that may be impacting the staging site quality and migration timing of long-distance migratory birds.

Initial indications of polycyclic aromatic hydrocarbon exposure in Saskatchewan common loons

Mercury (Hg) and polycyclic aromatic hydrocarbons (PAHs) are global pollutants known for their toxicity to wildlife. Because of their trophic position, common loons ( Gavia immer (Brünnich 1764)) are excellent indicators of environmental quality. In 2014 and 2015, tissue samples of ten adult common loons (plus one recapture) were obtained in Meadow Lake Provincial Park, Saskatchewan, and assessed for Hg and PAH exposure. Blood and feather levels of these contaminants are indicative of exposure during breeding and in wintering areas, respectively. Compared with an international Hg database, blood Hg levels were low (<1 μg/g). In most loons (90.5%, 10 out of 11), blood PAH concentrations were also low (<10 ng/g), but high (120 ng/g) for one individual (9.5% 1 out of 11). Feather PAH concentrations were high (95.9 ng/g and 250.6 ng/g) in two of the four loons (50%) caught in 2015. These data indicate that loons breeding in Meadow Lake Provincial Park were exposed to low levels of Hg; however, some individuals are being exposed to PAHs in both their breeding and wintering locations. The effect of these environmental pollutants on individual loon fitness is unclear, but because of their extreme toxicity in biological systems we suggest that future monitoring in the surrounding region is warranted.

Polycyclic aromatic hydrocarbon exposure in seaside sparrows (Ammodramus maritimus) following the 2010 Deepwater Horizon oil spill

The seaside sparrow (Ammodramus maritimus) is an abundant and permanent resident of coastal salt marshes impacted by the 2010 BP Deepwater Horizon oil spill. Such terrestrial species are often overlooked in the aftermath of marine spills, despite the potential for long-term oil exposure. We sampled the livers of seaside sparrows residing in oiled and unoiled sites from 2011 to 2014 and quantified expression of cytochrome p450 1A (CYP1A), a gene involved in the metabolism of polycyclic aromatic hydrocarbons (PAHs). In August 2011, CYP1A expression was markedly higher in birds from an oiled site compared to an unoiled site, but differences had disappeared by June 2012. In June 2013, CYP1A expression was elevated compared to 2012 levels on all sites, including those collected from sites that had not been directly oiled during the spill. This rise in CYP1A expression was possibly due to Hurricane Isaac, which made landfall near our sites between the 2012 and 2013 sampling periods. CYP1A expression was significantly attenuated again in June 2014. We also collected sediment samples from the same marshes for a total concentration analysis of PAHs. The PAH concentrations in sediment samples exhibited a similar pattern to the CYP1A data, supporting the link between marsh PAHs and bird CYP1A expression. These results indicate that contamination from marine oil spills can immediately extend to terrestrial ecosystems, and that storms, weather, or other factors may influence subsequent spatial and temporal oil exposure for several additional years.

Productivity of waterbirds in potentially impacted areas of Louisiana in 2011 following the Deepwater Horizon oil spill

The Deepwater Horizon oil spill (2010) could have affected the behavior and productivity of birds nesting along the Gulf of Mexico. This research examined the productivity of several species of colonial waterbirds in 2011 in LA colonies that were classified according to the M252 peak SCAT shoreline map oiling designations (as of April 6 2011) within 2 km of each colony. Colonies were classified as no oil, little oil, or medium to heavy oil. Because of the uneven distribution of oil and variation in bird composition within colonies, not all species occurred in each of the three oiling classes in the LA colonies studied. I tested the following hypotheses: (1) there were no interspecific differences in nesting phenology, (2) there were no differences in the number of species per colony as a function of oiling, and (3) there were no differences in reproductive measures as a function of oiling. Nesting phenology differed among species, with brown pelicans (Pelecanus occidentalis), great egrets (Ardea alba), and tri-colored herons (Egretta tricolor) nesting earlier than the other species. There were no significant differences in the number of species nesting in colonies as a function of oiling category. Along LA's shoreline, nests in colonies with a "no oil" category within 2 km of the colony had similar or lower maximum number of chicks/nest, than those from birds in colonies designated as light or moderate/heavy oiling. Average maximum chick sizes in nests in colonies designated as no oil were either similar to or smaller than chicks in nests in colonies designated as either category of oiled. The data suggest that in the year following the oil spill, there were no differences in reproductive success. Although long-term studies are essential to determine effects on population dynamics, the continued exposure of birds nesting along the Gulf of Mexico to acute and chronic oil sources make this a nearly impossible task.

Hematological indices of injury to lightly oiled birds from the Deepwater Horizon oil spill

Avian mortality events are common following large-scale oil spills. However, the sublethal effects of oil on birds exposed to light external oiling are not clearly understood. We found that American oystercatchers (area of potential impact n = 42, reference n = 21), black skimmers (area of potential impact n = 121, reference n = 88), brown pelicans (area of potential impact n = 91, reference n = 48), and great egrets (area of potential impact n = 57, reference n = 47) captured between 20 June 2010 and 23 February 2011 following the Deepwater Horizon oil spill experienced oxidative injury to erythrocytes, had decreased volume of circulating erythrocytes, and showed evidence of a regenerative hematological response in the form of increased reticulocytes compared with reference populations. Erythrocytic inclusions consistent with Heinz bodies were present almost exclusively in birds from sites impacted with oil, a finding pathognomonic for oxidative injury to erythrocytes. Average packed cell volumes were 4 to 19% lower and average reticulocyte counts were 27 to 40% higher in birds with visible external oil than birds from reference sites. These findings provide evidence that small amounts of external oil exposure are associated with hemolytic anemia. Furthermore, we found that some birds captured from the area impacted by the spill but with no visible oiling also had erythrocytic inclusion bodies, increased reticulocytes, and reduced packed cell volumes when compared with birds from reference sites. Thus, birds suffered hematologic injury despite no visible oil at the time of capture. Together, these findings suggest that adverse effects of oil spills on birds may be more widespread than estimates based on avian mortality or severe visible oiling. Environ Toxicol Chem 2018;37:451-461. © 2017 SETAC.

Homing pigeons as a biomonitor for atmospheric PAHs and PCBs in Guangzhou, a megacity in South China

The occurrence of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyl (PCBs) in urban atmosphere in Guangzhou, China were assessed using homing pigeons as a biomonitor. Contaminant concentrations in lung were significantly higher than those in liver and fat, indicating chemical uptake was mainly through respiratory route. Tricyclic PAHs and low chlorinated PCBs dominated composition of PAHs and PCBs in homing pigeons, similar as their composition in local atmosphere. Different age-dependent bioaccumulation patterns were noted for PAHs and PCBs. For 1-year old homing pigeons, higher levels of PAHs and PCBs in lung and liver tissues were probably ascribed to more intense flying than 5- and 10-year groups. Fat concentrations of PCBs were greater in aged pigeons than 1-year old pigeons, but PAH concentrations in fat slightly decreased in aged pigeons because of relatively fast biotransformation. Overall, homing pigeons could serve as a suitable biomonitor for urban atmospheric contaminants in coastal cities.

CAPSULE

Homing pigeons could serve as a good biomonitor for PAHs and PCBs in urban atmosphere, yet different biotransformation potential of the chemicals caused different bioaccumulation patterns in pigeon fat.

Challenges to Oil Spill Assessment for Seabirds in the Deep Ocean

We synthesize impediments for evaluating effects to seabirds from open ocean hydrocarbon releases. Effects on seabirds from ship discharges, spills, and well blowouts often are poorly detected and monitored far from land. Regulatory regimes for ocean spills can result in monitoring efforts that are not entirely transparent. We illustrate how interdisciplinary technologies address deficits that hamper individual or population level assessments for seabirds, and we demonstrate where emerging technologies might be engaged to bridge gaps in oil spill monitoring. Although acute mortality from direct oil exposure poses the greatest risk to seabirds, other hazards from light-attraction, flaring, collisions, chronic pollution, and hydrocarbon inhalation around oil infrastructure also may induce bird mortality in the deep ocean.

Mutagenicity and oxidative damage induced by an organic extract of the particulate emissions from a simulation of the deepwater horizon surface oil burns

Emissions from oil fires associated with the "Deepwater Horizon" explosion and oil discharge that began on April 20, 2010 in the Gulf of Mexico were analyzed chemically to only a limited extent at the time but were shown to induce oxidative damage in vitro and in mice. To extend this work, we burned oil floating on sea water and performed extensive chemical analyses of the emissions (Gullett et al., Marine Pollut Bull, in press, ). Here, we examine the ability of a dichloromethane extract of the particulate material with an aerodynamic size ≤ 2.5 µm (PM2.5 ) from those emissions to induce oxidative damage in human lung cells in vitro and mutagenicity in 6 strains of Salmonella. The extract had a percentage of extractable organic material (EOM) of 7.0% and increased expression of the heme oxygenase (HMOX1) gene in BEAS-2B cells after exposure for 4 hr at 20 µg of EOM/ml. However, the extract did not alter mitochondrial respiration rate as measured by extracellular flux analysis. The extract was most mutagenic in TA100 +S9, indicative of a role for polycyclic aromatic hydrocarbons (PAHs), reflective of the high concentrations of PAHs in the emissions (1 g/kg of oil consumed). The extract had a mutagenicity emission factor of 1.8 ± 0.1 × 105 revertants/megajoulethermal in TA98 +S9, which was greater than that of diesel exhaust and within an order of magnitude of open burning of wood and plastic. Thus, organics from PM2.5 of burning oil can induce oxidative responses in human airway epithelial cells and are highly mutagenic. Environ. Mol. Mutagen. 58:162-171, 2017. © 2017 Wiley Periodicals, Inc.

Soil bioremediation approaches for petroleum hydrocarbon polluted environments

Increasing industrialisation, continued population growth and heavy demand and reliance on petrochemical products have led to unprecedented economic growth and development. However, inevitably this dependence on fossil fuels has resulted in serious environmental issues over recent decades. The eco-toxicity and the potential health implications that petroleum hydrocarbons pose for both environmental and human health have led to increased interest in developing environmental biotechnology-based methodologies to detoxify environments impacted by petrogenic compounds. Different approaches have been applied for remediating polluted sites with petroleum derivatives. Bioremediation represents an environmentally sustainable and economical emerging technology for maximizing the metabolism of organic pollutants and minimizing the ecological effects of oil spills. Bioremediation relies on microbial metabolic activities in the presence of optimal ecological factors and necessary nutrients to transform organic pollutants such as petrogenic hydrocarbons. Although, biodegradation often takes longer than traditional remediation methods, the complete degradation of the contaminant is often accomplished. Hydrocarbon biodegradation in soil is determined by a number of environmental and biological factors varying from site to site such as the pH of the soil, temperature, oxygen availability and nutrient content, the growth and survival of hydrocarbon-degrading microbes and bioavailability of pollutants to microbial attack. In this review we have attempted to broaden the perspectives of scientists working in bioremediation. We focus on the most common bioremediation technologies currently used for soil remediation and the mechanisms underlying the degradation of petrogenic hydrocarbons by microorganisms.