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Patterns of genetic variation reflect interactions among microevolutionary forces that vary in strength with changing demography. Here, patterns of variation within and among samples of the mouthbrooding gafftopsail catfish (Bagre marinus, Family Ariidae) captured in the U.S. Atlantic and throughout the Gulf of Mexico were analyzed using genomics to generate neutral and non‐neutral SNP data sets. Because genomic resources are lacking for ariids, linkage disequilibrium network analysis was used to examine patterns of putatively adaptive variation. Finally, historical demographic parameters were estimated from site frequency spectra. The results show four differentiated groups, corresponding to the (1) U.S. Atlantic, and the (2) northeastern, (3) northwestern, and (4) southern Gulf of Mexico. The non‐neutral data presented two contrasting signals of structure, one due to increases in diversity moving west to east and north to south, and another to increased heterozygosity in the Atlantic. Demographic analysis suggested that recently reduced long‐term effective population size in the Atlantic is likely an important driver of patterns of genetic variation and is consistent with a known reduction in population size potentially due to an epizootic. Overall, patterns of genetic variation resemble that of other fishes that use the same estuarine habitats as nurseries, regardless of the presence/absence of a larval phase, supporting the idea that adult/juvenile behavior and habitat are important predictors of contemporary patterns of genetic structure. Gafftopsail catfish show high levels of genetic structuring across their distribution in the U.S., Atlantic and Gulf of Mexico. Non‐neutral data present two contrasting signals of structure and historical demography is likely an important driver of patterns of neutral and non‐neutral genetic variation. Results of this study are similar to what is seen in other fishes that use the same estuarine habitats as nurseries, but gafftopsail catfish lack a larval phase, supporting the idea that adult/juvenile behavior and habitat use are important predictors of contemporary patterns of genetic structure.

The goal of this paper was to review the evidence of population-level impacts of the Deepwater Horizon Oil Spill (DWH) on Gulf of Mexico (GOM) continental shelf taxa, as well as evidence of resiliency following the DWH. There is considerable environmental and biological evidence that GOM shelf taxa were exposed to and suffered direct and indirect impacts of the DWH. Numerous assessments, from mesocosm studies to analysis of biopsied tissue or tissue samples from necropsied animals, revealed a constellation of physiological effects related to DWH impacts on GOM biota, some of which clearly or likely resulted in mortality. While the estimated concentrations of hydrocarbons in shelf waters and sediments were orders of magnitude lower than measured in inshore or deep GOM environments, the level of mortality observed or predicted was substantial for many shelf taxa. In some cases, such as for zooplankton, community shifts following the spill were ephemeral, likely reflecting high rates of population turnover and productivity. In other taxa, such as GOM reef fishes, impacts of the spill are confounded with other stressors, such as fishing mortality or the appearance and rapid population growth of invasive lionfish ( Pterois spp.). In yet others, such as cetaceans, modeling efforts to predict population-level effects of the DWH made conservative assumptions given the species’ protected status, which post-DWH population assessments either failed to detect or population increases were estimated. A persistent theme that emerged was the lack of precise population-level data or assessments prior to the DWH for many taxa, but even when data or assessments did exist, examining evidence of population resiliency was confounded by other stressors impacting GOM biota. Unless efforts are made to increase the resolution of the data or precision of population assessments, difficulties will likely remain in estimating the scale of population-level effects or resiliency in the case of future large-scale environmental catastrophes.

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.

The primary source of chronic exposures to per- and polyfluoroalkyl substances (PFASs) in humans is through the ingestion of contaminated foods and drinking water, with fish and other seafood being a major contributor. Nevertheless, there is scant literature on the dietary exposure to PFASs for the general United States (U.S.) population. The Tampa Bay (Florida, USA) region has the highest population density in the State and communities and their attendant support services are arrayed in an urban to semi-rural continuum from the head of the Bay to the ocean mouth. Tampa Bay supports productive recreational and commercial fisheries, providing a diverse community of species. A variety of potential PFAS sources surround Tampa Bay including airports, industry, wastewater treatment plants, fire-fighting training areas and military installations. The objective of this study is to quantify PFASs in sediment and fishes collected from Tampa Bay to further estimate human health risks from dietary exposures. Sediment ( n = 17) and fish (24 species, n = 140) were collected throughout Tampa Bay in 2020 and 2021 and analyzed for 25 PFAS compounds. Concentrations of PFASs in sediments and edible tissues of fish ranged from 36.8 to 2,990 ng kg -1 (dry weight) and 307 to 33,600 ng kg -1 (wet weight), respectively. Generally, levels were highest in Old Tampa Bay and decreased south towards the Gulf of Mexico. Profiles in both matrices were generally dominated by perfluorooctane sulfonic acid (PFOS) with variations by location. Estimated human health risks from the consumption of contaminated fish collected in Tampa Bay exceeded concentration thresholds for minimum risk levels (MRLs) and tolerable weekly intake (TWIs) values for adults and youths. Additionally, concentrations of PFOS in edible fish tissues of several recreationally important species collected in Tampa Bay exceeded consumption guideline levels established by several governmental agencies. In the current context, the elevated levels of PFAS in Tampa Bay and the exceedances of available thresholds for potential human health risks are a cause for concern and justify a more intensive examination especially for more heavily utilized species, particularly those used in subsistence-level fishing, which, as elsewhere may be significantly under documented.

One year after the Deepwater Horizon oil spill accident, semipermeable membrane devices (SPMDs) and polyethylene devices (PEDs) were deployed in wetland areas and coastal areas of the Gulf of Mexico (GOM) to monitor polycyclic aromatic hydrocarbons (PAHs). The measured PAH levels with the PEDs in coastal areas were 0.05–1.9 ng/L in water and 0.03–9.7 ng/L in sediment porewater. With the SPMDs, the measured PAH levels in wetlands (Barataria Bay) were 1.4–73 ng/L in water and 3.3–107 ng/L in porewater. The total PAH concentrations in the coastal areas were close to the reported baseline PAH concentrations in GOM; however, the total PAH concentrations in the wetland areas were one or two orders of magnitude higher than those reported in the coastal areas. In light of the significant spatial variability of PAHs in the Gulf’s environments, baseline information on PAHs should be obtained in specific areas periodically.

Although the Turtle/Brunswick River Estuary (TBRE) in coastal Georgia (USA) is severely contaminated by persistent organochlorine pollutants (POPs), little information regarding POPs in higher‐trophic‐level biota in this system is available. In the present study, polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs; including DDTs, chlordanes, and mirex), and chlorinated monoterpenes (toxaphene) were measured using gas chromatography with electron‐capture detection and gas chromatography with electron‐capture negative ion mass spectrometry (GC‐ECNI‐MS) in blubber of free‐ranging and stranded bottlenose dolphins (Tursiops truncatus). Mean total PCBs (78.6 ± 32.4 μg/g lipid) and toxaphene (11.7 ± 9.3 μg/g lipid) were significantly higher in dolphins sampled in the TBRE than in dolphins stranded near Savannah (GA, USA) 80 to 100 km to the north. Levels of OCPs were several‐fold lower than levels of PCBs; moreover, PCBs comprised 81 and 67% of the total POP burden in TBRE and non‐TBRE dolphins, respectively. Analyses with GC‐ECNI‐MS revealed that 2,2,5‐endo,6‐exo,8,8,9,10‐octachlorobornane (P‐42a), a major component in technical toxaphene and a major residue congener in local estuarine fish species, was the most abundant chlorobornane in both sets of blubber samples. Mean total POP concentrations (sum of PCBs, OCPs, and toxaphene) approached 100 μg/g lipid for the TBRE animals, well above published total PCB thresholds at which immunosuppresion and/or reproductive anomalies are thought to occur. These results indicate extended utilization of the highly contaminated TBRE as habitat for a group of coastal estuarine dolphins, and they further suggest that these animals may be at risk because of elevated POP concentrations.

Legacy organochlorine (OC) contaminants continue to pose a potential risk to ecological and human health in coastal aquatic ecosystems of the southeastern United States. Polychlorinated biphenyls (PCBs) and toxaphene (TOX) were analyzed by gas chromatography with electron capture detection and negative chemical ionization mass spectrometry in 77 composites of four inshore fish species commonly preyed upon by bottlenose dolphins (Tursiops truncatus) from estuaries near Savannah, Georgia (SAV), Brunswick, Georgia (BRN), and Jacksonville, Florida (JAX), USA. Whereas seasonal and species‐specific differences were minimal, differences among mean total PCB concentrations (∑PCBs) by estuary (42.0 ± 48.3, 1.59 ± 1.24, and 0.281 ± 0.075 μg/g lipid for BRN, JAX, and SAV, respectively) were highly significant. This estuary‐specific trend also held true for mean total toxaphene concentrations (∑TOX): 49 ± 100 (BRN), 1.2 ± 0.52 (JAX), and 0.40 ± 0.19 μg/g lipid (SAV). Congener profiles of PCBs also were found to be significantly different among estuaries, with BRN and (to a lesser extent) JAX samples enriched with highly chlorinated homologs associated with Aroclor 1268, a legacy OC linked to a historical point source in Brunswick. The observed spatial heterogeneity in OC concentrations and PCB congener profiles suggests that contaminated fish from Brunswick pose the greatest risk to ecological and human health via biomagnification and seafood consumption; highly chlorinated PCBs (and possibly toxaphene) are transported in a southerly, alongshore direction; and the uniqueness of Aroclor 1268 underscores its utility as a signature proxy in future regional ecotoxicological studies.

Refinery operations have been associated with a wide variety of atmospheric emissions consisting of criteria air pollutants, volatile organic components, hazardous air pollutants as well as other pollutants. With approximately 100 oil refineries in the Wider Caribbean region (WCR), hydrocarbons in this region pose significant environmental and human health risks. One of the oldest and largest refineries in the WCR is the Isla Refineriá, which is located on the island of Curaçao, and has been the basis of historical debates and conflict between the public and the local government over the environmental and human health risks. This research aims to establish baseline levels of ambient petrochemical emissions in Curaçao, specifically polycyclic aromatic hydrocarbons (PAHs), inhalable particulate matter (PM10) and sulfur dioxide (SO2), and to evaluate through comparative literature analysis and recommended public health guidelines the potential health risks in Curaçao. In addition, source elucidation of PAHs was conducted using concentration profiles, distribution profiles, binary diagnostic ratios and factor analysis. Passive air samplers with polyurethane foam collection disks (PAS-PUFs) were deployed in 2011 (n=43) and in 2014 (n=30) to measure ambient PAH concentrations. Ambient PAH concentrations ranged from 1.2 ng/m3 in 2011 and 27.3 to 660.1 ng/m 3 in 2014, demonstrating no temporal differences. However, there were highly significant spatial differences, with the samples downwind of the refinery having significantly higher ambient PAH concentrations than those upwind in 2014. Source elucidation revealed the ambient PAHs were dominated by petrogenic emission sources (i.e., refinery) in the 2011 and the 2014 downwind samples, whereas the 2014 upwind locations were equally influenced by both petrogenic (i.e., refinery) and pyrogenic (i.e., vehicle emissions) sources. Available hourly, daily and monthly PM10 and SO2 measurements were downloaded from June 2010 through December 2014 from two local air monitoring stations. Concentrations of both PM10 and SO2 in Curaçao are among the highest reported globally, demonstrating an increasing trend over time and exceed current public health guidelines recommended by local and international agencies. It is plausible that the residents of Curaçao may experience health effects often associated with PM10 and SO 2, however the epidemiological evidence is inadequate to infer causality between health effects and long-term exposures. Using the USEPA's risk analysis methodology the resulting cumulative lifetime cancer risk estimates from PAH inhalation were below the level of concern (1.0 × 10-4). In contrast, by evaluating the potency adjusted concentrations relative to the most toxic compound (benzo[a]pyrene), age class (children and adults) extrapolated and site specific risks indicated levels exceeding the upper bound acceptable risk (1.0 × 10-4) by almost two orders of magnitude suggesting the need for remediation.

Although the Turtle/Brunswick River Estuary (TBRE) in coastal Georgia (USA) is severely contaminated by persistent organochlorine pollutants (POPs), little information regarding POPs in higher-trophic-level biota in this system is available. In the present study, polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs; including DDTs, chlordanes, and mirex), and chlorinated monoterpenes (toxaphene) were measured using gas chromatography with electron-capture detection and gas chromatography with electron-capture negative ion mass spectrometry (GC-ECNI-MS) in blubber of free-ranging and stranded bottlenose dolphins (Tursiops truncatus). Mean total PCBs (78.6 +/- 32.4 microg/g lipid) and toxaphene (11.7 +/- 9.3 microg/g lipid) were significantly higher in dolphins sampled in the TBRE than in dolphins stranded near Savannah (GA, USA) 80 to 100 km to the north. Levels of OCPs were several-fold lower than levels of PCBs; moreover, PCBs comprised 81 and 67% of the total POP burden in TBRE and non-TBRE dolphins, respectively. Analyses with GC-ECNI-MS revealed that 2,2,5-endo,6-exo,8,8,9,10-octachlorobornane (P-42a), a major component in technical toxaphene and a major residue congener in local estuarine fish species, was the most abundant chlorobornane in both sets of blubber samples. Mean total POP concentrations (sum of PCBs, OCPs, and toxaphene) approached 100 microg/g lipid for the TBRE animals, well above published total PCB thresholds at which immunosuppresion and/or reproductive anomalies are thought to occur. These results indicate extended utilization of the highly contaminated TBRE as habitat for a group of coastal estuarine dolphins, and they further suggest that these animals may be at risk because of elevated POP concentrations.

Excluding carbon dioxide, carbon monoxide (CO) is considered as one of the most abundant and widely distributed air pollutants in the lower atmosphere. This chapter discusses the physical and chemical properties of CO. Toxic effects of CO are primarily caused by its ability to bind to heme, and alter the function and metabolism of proteins. Acute poisoning has the potential for serious injury to major organs, brain, heart, kidney and muscles, yet it is not believed to accumulate. Symptoms of chronic CO effects that are most commonly reported and observed include headache, irritability, insomnia, and personality disturbances. CO poisoning is now the most common of all poisonings in industry and is responsible for more than half of the poisoning fatalities reported each year in the United States. Occupational Safety and Health Administration (OSHA) recommends workers who have inhaled large volumes of CO be moved to fresh air immediately.