River otters of the Green-Duwamish: biomonitors of ecological health

River otters (Lontra canadensis) are apex predators that play an important role in aquatic ecosystems. They accumulate contaminants via their diet of fish and invertebrates, potentially serving as biomonitors of watershed health. In summer and fall 2016, we collected 33 otter scats from sites along the Green-Duwamish River, ranging from river miles 0-54. River miles 0-5 represent the Lower Duwamish Waterway (LDW), a U.S. Superfund site slated for a 17-year remediation. Concentrations of polychlorinated biphenyls (PCBs) at sites in the LDW were 9.1 and 19.3 mg/kg (geometric means, lipid weight) - above the reported threshold value of 9 mg/kg associated with adverse effects for river otters. By river mile 10, mean concentrations of PCBs decreased to 2.6 mg/kg, with remaining upriver sites ranging from 0.4-1.9 mg/kg. Polycyclic aromatic hydrocarbon (PAH) concentrations showed a similar pattern. The highest PAH levels (140 and 91 mg/kg, geometric means, wet weight) were measured in the LDW whereas levels upriver were 9.7-25 mg/kg. Based on preliminary genetics data from several sampling locations, we infer that otters remain in local river reaches, so scat contaminant levels reflect local environmental concentrations. These are the only empirical contaminant data available for a mammal or apex predator in the Green-Duwamish, and they reveal: 1) otters may be impacted by contaminant loads in the LDW; 2) the contamination gradient along the Green-Duwamish is reflected in otters, indicating they may be useful biomonitors; and 3) a baseline level of contamination in otters that may be of great value for assessing ecological impacts of long-term cleanup efforts. Scat collected in 2017 and analyses for brominated flame retardants, organochlorine pesticides, stable isotopes, and genetics will provide additional depth and breadth to these results. Significant questions remain as to the potential individual health and population impacts of environmental contaminants in this top-level aquatic predator

Potent Phototoxicity of Marine Bunker Oil to Translucent Herring Embryos after Prolonged Weathering

Pacific herring embryos (Clupea pallasi) spawned three months following the Cosco Busan bunker oil spill in San Francisco Bay showed high rates of late embryonic mortality in the intertidal zone at oiled sites. Dead embryos developed to the hatching stage (e.g. fully pigmented eyes) before suffering extensive tissue deterioration. In contrast, embryos incubated subtidally at oiled sites showed evidence of sublethal oil exposure (petroleum-induced cardiac toxicity) with very low rates of mortality. These field findings suggested an enhancement of oil toxicity through an interaction between oil and another environmental stressor in the intertidal zone, such as higher levels of sunlight-derived ultraviolet (UV) radiation. We tested this hypothesis by exposing herring embryos to both trace levels of weathered Cosco Busan bunker oil and sunlight, with and without protection from UV radiation. Cosco Busan oil and UV co-exposure were both necessary and sufficient to induce an acutely lethal necrotic syndrome in hatching stage embryos that closely mimicked the condition of dead embryos sampled from oiled sites. Tissue levels of known phototoxic polycyclic aromatic compounds were too low to explain the observed degree of phototoxicity, indicating the presence of other unidentified or unmeasured phototoxic compounds derived from bunker oil. These findings provide a parsimonious explanation for the unexpectedly high losses of intertidal herring spawn following the Cosco Busan spill. The chemical composition and associated toxicity of bunker oils should be more thoroughly evaluated to better understand and anticipate the ecological impacts of vessel-derived spills associated with an expanding global transportation network

Persistent Organic Pollutants (POPs) in the Puget Sound Ecosystem: An evaluation of POPs in fecal samples of Southern Resident killer whales

The Puget Sound ecosystem of Washington State has been riddled with human impacts. Exposure to persistent organic pollutants (POPs) is listed as a primary risk factor for the endangered Southern Resident killer whale (SRKWs, Orcinus orca) population that resides in these waters. The objective of this study is to obtain real-time measures of POP (PBDEs, PCBs, and DDTs) levels in SRKW scat (fecal) samples to quantify variations in toxicant levels by pod, age, sex, reproductive status, and birth order, as well as prey availability and year. Samples were collected using detection dogs that ride on the bow of a boat and use scent to locate fresh scat on the water’s surface. Using this non-invasive method we collected 267 samples over 4 years (2010-2013) across our 5-month study period. In our validation study using samples from 14 individual whales, gas chromatography/mass spectrometry was used to quantify contaminant levels, reproductive and thyroid hormones measurements were measured by radioimmunoassay, and species/individual was confirmed by DNA analysis. Significant correlations were apparent between toxicant measurements in scat and previously analyzed blubber-biopsy samples from the same whale (n=7 unique pairs; ∑PCBs, r=0.75, p=0.05; ∑PBDEs, r=0.76, p=0.05; ∑DDTs, r=0.92, p \u3c 0.01). Consistent with blubber biopsy measurements, the toxicant profiles in scat samples demonstrate significantly higher ∑DDT/∑PCB ratios in K and L pods, known to forage off the California coast, compared to J pod (p=0.02 and 0.02, respectively), and significantly lower (p \u3c 0.05) levels of ∑PCB, ∑PBDE, and ∑DDT were detected in reproductive age females compared to males and post-reproductive females, adjusted for pod. These validated measures will be applied to all samples to investigate temporal patterns and variations in toxicant levels relative to population demographics, hormones measures, and environmental factors. Results are forthcoming and will be presented at the conference

The threat of toxic contaminants to Southern Resident killer whales: monitoring POPs and PAHs in scat samples

The Southern Resident killer whale population (SRKW; Orcinus orca) feed primarily on Chinook salmon, which is currently their primary source of exposure to toxics. We measured lipophilic persistent organic pollutants (POPs: PBDEs, PCBs, and DDTs) in SRKW scat (fecal) samples to quantify variations in toxicant levels by pod, sex, and reproductive class, as well as prey availability. We also measured polycyclic aromatic hydrocarbons (PAHs), which do not generally bioaccumulate and would reflect recent exposure to oil, engine (combustion) exhaust, among other potential exposure sources. Samples were collected using detection dogs that use scent to locate fresh SRKW scat on the water’s surface. We collected 267 samples during four 5-month study periods between 2010 and 2013. POP levels in scat had expected trends, such as increasing with age and decreasing by number of calves (for adult females). POPs were also highest when the whales primary prey source was at low seasonal abundance, presumably due to metabolizing endogenous lipid stores. By contrast, overall measures of PAHs were low (ppb, wet weight), as expected. However, PAHs indicative of motor exhaust versus oil exposure were relatively high prior to implementation of guidelines aimed at increasing vessel distances to the whales. Results point to the value of monitoring POPs by age, sex and reproductive class and in relation to changes in prey abundance to help identify what reproductive classes are most at risk to high toxic loads, what season the liability is greatest, and whether prey recovery and clean up efforts are working. The PAH exposure data will be available as baseline in SRKW feces in relation to environmental events over time, such as the circumstance of an oil spill in the Salish Sea. Addressing toxics and other vulnerabilities is important for SRKW recovery

Contaminant and health monitoring of endangered Southern Resident killer whales

The Environmental Chemistry Program at NOAA’s Northwest Fisheries Science Center has been analyzing chemical tracers, including environmental pollutants, stable isotope ratios and fatty acids, in support of studies related to NOAA trust resources for more than 40 years. These analyses are conducted for a range of NOAA mission-critical projects such as: ensuring the safety of seafood in response to natural and anthropogenic disasters and providing scientific support on NOAA Natural Resource Damage Assessment litigation-sensitive studies on protected species such as Chinook salmon, marine mammals and sea turtles, and providing data that help describe the population age structure and foraging ecology (including marine distribution) of populations of ESA-listed marine mammals and salmonids. Southern Resident killer whales were listed as endangered in the United States and Canada as a result of the population declining. Since the early 1990s, US and Canadian studies have characterized toxic persistent organic pollutants (POPs) as a threat to this population. As long-lived top predators, Southern Residents are vulnerable to contaminants that occur in urban and industrial areas with high shipping and vessel activities such as Puget Sound where they reside and feed. Studies to date have shown that Southern Residents contain higher POPs concentrations than those in northern residents and other northeastern Pacific killer whale populations, and that contaminant burden and exposure are strongly associated with sex and age. Data have largely been derived from non-lethal remote biopsy samples and analyses conducted on blubber and skin. In addition to POPs, measurements of petroleum related hydrocarbons and total mercury have also been conducted to characterize baseline levels. More recently, investigations have been conducted on feces to investigate POPs as well as reproductive and stress steroids, and on breath samples to investigate pathogenic microbes and antibiotic resistant bacteria, to increase our knowledge on the health of this population

Severe Coal Tar Sealcoat Runoff Toxicity to Fish Is Prevented by Bioretention Filtration

Coal tar sealcoats applied to asphalt surfaces in North America, east of the Continental Divide, are enriched in petroleum-derived compounds, including polycyclic aromatic hydrocarbons (PAHs). The release of PAHs and other chemicals from sealcoat has the potential to contaminate nearby water bodies, reducing the resiliency of aquatic communities. Despite this, relatively little is known about the aquatic toxicology of sealcoat-derived contaminants. We assessed the impacts of stormwater runoff from sealcoated asphalt on juvenile coho salmon (<i>Oncorhynchus kisutch</i>) and embryo-larval zebrafish (<i>Danio rerio).</i> We furthermore evaluated the effectiveness of bioretention as a green stormwater method to remove PAHs and reduce lethal and sublethal toxicity in both species. We applied a coal tar sealcoat to conventional asphalt and collected runoff from simulated rainfall events up to 7 months postapplication. Whereas sealcoat runoff was more acutely lethal to salmon, a spectrum of cardiovascular abnormalities was consistently evident in early life stage zebrafish. Soil bioretention effectively reduced PAH concentrations by an order of magnitude, prevented mortality in juvenile salmon, and significantly reduced cardiotoxicity in zebrafish. Our findings show that inexpensive bioretention methods can markedly improve stormwater quality and protect fish health

Severe Coal Tar Sealcoat Runoff Toxicity to Fish Is Prevented by Bioretention Filtration

Coal tar sealcoats applied to asphalt surfaces in North America, east of the Continental Divide, are enriched in petroleum-derived compounds, including polycyclic aromatic hydrocarbons (PAHs). The release of PAHs and other chemicals from sealcoat has the potential to contaminate nearby water bodies, reducing the resiliency of aquatic communities. Despite this, relatively little is known about the aquatic toxicology of sealcoat-derived contaminants. We assessed the impacts of stormwater runoff from sealcoated asphalt on juvenile coho salmon (<i>Oncorhynchus kisutch</i>) and embryo-larval zebrafish (<i>Danio rerio).</i> We furthermore evaluated the effectiveness of bioretention as a green stormwater method to remove PAHs and reduce lethal and sublethal toxicity in both species. We applied a coal tar sealcoat to conventional asphalt and collected runoff from simulated rainfall events up to 7 months postapplication. Whereas sealcoat runoff was more acutely lethal to salmon, a spectrum of cardiovascular abnormalities was consistently evident in early life stage zebrafish. Soil bioretention effectively reduced PAH concentrations by an order of magnitude, prevented mortality in juvenile salmon, and significantly reduced cardiotoxicity in zebrafish. Our findings show that inexpensive bioretention methods can markedly improve stormwater quality and protect fish health

Potent phototoxicity of marine bunker oil to translucent herring embryos after prolonged weathering.

Pacific herring embryos (Clupea pallasi) spawned three months following the Cosco Busan bunker oil spill in San Francisco Bay showed high rates of late embryonic mortality in the intertidal zone at oiled sites. Dead embryos developed to the hatching stage (e.g. fully pigmented eyes) before suffering extensive tissue deterioration. In contrast, embryos incubated subtidally at oiled sites showed evidence of sublethal oil exposure (petroleum-induced cardiac toxicity) with very low rates of mortality. These field findings suggested an enhancement of oil toxicity through an interaction between oil and another environmental stressor in the intertidal zone, such as higher levels of sunlight-derived ultraviolet (UV) radiation. We tested this hypothesis by exposing herring embryos to both trace levels of weathered Cosco Busan bunker oil and sunlight, with and without protection from UV radiation. Cosco Busan oil and UV co-exposure were both necessary and sufficient to induce an acutely lethal necrotic syndrome in hatching stage embryos that closely mimicked the condition of dead embryos sampled from oiled sites. Tissue levels of known phototoxic polycyclic aromatic compounds were too low to explain the observed degree of phototoxicity, indicating the presence of other unidentified or unmeasured phototoxic compounds derived from bunker oil. These findings provide a parsimonious explanation for the unexpectedly high losses of intertidal herring spawn following the Cosco Busan spill. The chemical composition and associated toxicity of bunker oils should be more thoroughly evaluated to better understand and anticipate the ecological impacts of vessel-derived spills associated with an expanding global transportation network

Morphological condition of Pacific herring embryos collected from field sites in San Francisco Bay in February 2008.

<p>Sampling and imaging of embryos is described elsewhere (1). (A) Opaque dead embryos within chorions from a site (Sausalito waterfront) affected by the Cosco Busan spill. Arrows indicate pigmented eyes on an embryo protruding from a ruptured chorion, while yellow dashed lines outline the “ghosts” of necrotic late embryos. (B) Embryos within chorions from the same site after recovery in February 2010. Viable hatching-stage embryos are translucent, with pigmented eyes indicated by arrows. Scale bar 1 mm.</p