There is a concerted effort in the regionto understand the sources, fate, transport and

Transcription

1 There is a concerted effort in the regionto understand the sources, fate, transport and impacts of toxic to the Salish Sea with the intent of determining best management options to reduce toxic threats. options to reduce toxic threats to Chinook salmon, particularly threats from PCBs, given what we know about trends in PCB in levels in Puget Sound fish and modeled PCB loadings to Puget Sound via major pathways. 1

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3 Chinook salmon are anicon in the Pacific Northwest. Chinook salmon are the least abundant of the five species of Pacific salmon but because of their large size and high fat content, they are highly valued in commercial recreational and aboriginal fisheries. They are also culturally important to First Nations. The Puget Sound Partnership considers Chinook salmon to be an umbrella species, whose environmental requirements are believed to encapsulate the needs of many species. Chinook salmon have very complex habitat requirements involving freshwater, nearshoreand marine systems so protection and restoration efforts to enhance abundance of Chinook salmon should protect and restore many other species. The selection of Chinook salmon along with other select focal species that consider a range of habitat types and landscape attributes should help to conserve species and food webs in the Salish Sea. 3

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5 Salish Sea Chinooksalmon are particularly susceptible to toxic exposure. Waters of the Salish Sea have limited exchange with oceanic waters, especially the Puget Sound. So toxics that get into the sound stay in the sound. Juvenilesalmon migrating through and feeding in urban bays are exposed to contaminated sediments in the nearshore. In addition, the depth of the Sound creates a deep-water marine habitat that can be used year-round by sub-adult Chinook salmon. Approximately 29% Puget Sound Chinook salmon are estimated to reside in Puget Sound (O Neill and West 2009; TAFS 138: ). Similarly, the Harrison Chinook salmon, the most abundant population from the Fraser River, is also know to have more local marine distribution in the Salish Sea the west coast on Vancouver Island. 5

6 Relative to other Chemical of Concern (COC) that have been evaluated, PCBs are are major threat to the Salish Sea and to Chinook salmon in particular. A recent report by the Department of Ecology (Norton et al Assessment of Selected Toxic Chemicals in the Puget Sound Basin, ; documented that the PCBs were the most hazardous of the 17 COCs evaluated for the Puget Sound basin. With respect to Chinook salmon, Cullonet al (Environmental Toxicology and Chemistry, 28(1) ) documented that PCBs accounted for the greatest proportion of toxicity associated with measured levels of PCB, PBDEsand PCDDsin lower Fraser River and Puget Sound Chinook salmon. Currently, 23 % to 100% of juvenile fish from urban bays in Puget Sound and 19 % of adult salmon returning to Puget Sound rivers havepcbs levels above an effects thresholds established by National Marine Fisheries Service (Meador et al. 2002; Aquatic Conservation: Marine and Freshwater Ecosystems, 12: ) which is below the 2020 recovery target adopted by the Puget Sound Partnership (West et al Current conditions, time trends and recovery targets for toxic contaminants in Puget Sound fish: the Toxics in FishDashboard Indicator. Poster/submitted paper at the 2011 Salish Sea Ecosystem Conference). PCB data for juvenile Chinook salmon is based on published and unpublished data from NOAA - NWFSC. PCB data for adult Chinook salmon is based on data from O Neill et al 2006, extended abstract for 2006 Southern resident killer whale symposium; PSAT 2007, 2007 Puget Sound Update: 9 th Report of the Puget Sound Assessment and Monitoring Program. 6

7 The Puget Sound Partnership has four categories of strategies to reduce the toxic threat to the Puget Sound: 1) prevent releases, 2) control inputs of released toxics, 3) restoration/remediate toxic contaminated sites and 4) natural attenuation of toxic contaminated sites. Detailed DRAFT strategies and near term action currently under consideration can be viewed at Briefly, prevention strategies to reduce the sources of toxic chemical entering Puget Sound include: implement and strengthen authorities and programs to prevent toxic chemicals from entering the Puget Sound environment; promote the development and use of safer alternatives to toxic chemicals; adopt and implement plans and control strategies to reduce toxic releases into the Puget Sound from air emissions; provide education and technical assistance to prevent and reduce toxic releases; and increase compliance with and enforcement of environmental laws, regulations, and permits. Control strategies to reduce pressures on the Puget Sound ecosystem from runoff from the built environment include: manage urban runoff at the basin and watershed scale; prevent problems from new development at the site & subdivision scale (e.g. LIDs); fix problems caused by existing development (e.g. stormwater retrofits); control sources of pollutants in runoff; provide focused stormwater related education and training; and assess effectiveness of actions and effects on the environment. Additional control strategies to reduce pressures on the Puget Sound ecosystem from wastewater have also been identified. Restoration/ remediation strategies to address and clean up cumulative water pollution impacts in Puget Sound include: complete total maximum daily load (TMDL) studies and other necessary water cleanup plans for Puget Sound to set pollution discharge limits and determine response strategies to address water quality impairments; and clean up contaminated sites within and near Puget Sound. 7

8 Selected management options for PCB depend on 1) loading amount and pathway,2) the existing PCB mass in Puget Sound,and 3) whether toxics are retained in the food web. Within Puget Sound Pelletier and Mohamedali 2009 ( developed a PCB Box Model to predict the effects of loading of PCBs on the concentrations of PCB in the water, sediment, and biota of Puget Sound. Within this model, the various Puget Sound basins are boxes. The numerical modeling approach for this project is composed of three parts: 1) Box model of circulation and transport of water. 2) Mass balance model of contaminant fate and transport. 3) Food web bioaccumulation model. 8

9 Major potentialpathways for loading PCBsto Puget Sound include: surface runoff, groundwater, direct air deposition and waste water treatment plants (publicly owned treatment works). Pollutants may differ in loadings via major pathwayand thus mayrequire different solutions to get rid of them. At thesite and at the Puget Sound Scale, the PCB Box Model predicts that sediment and water concentrations are very sensitive to incoming loads. Therefore, reducing PCB loading will directly reduce water and sediment contamination directly and indirectly PCB exposure in fish. 9

10 Puget Sound Toxics Loadings Analysis evaluated loadings of PCB and other chemical of concern to Puget Sound via 4 major pathways (Norton et al.2011; see Table 13; Estimates are not available for groundwater. The current median PCB loading estimate to Puget Sound from all major pathways is 7.7 kg/yr (Norton et al.2011; see Table 13; Themajority of PCB loading to Puget Sound comes from surface runoff (5.3 kg/yr) and most of that is in runoff from forested lands (Herrera 2011, Table 15; 10

11 Puget Sound Toxics Loadings Analysis predicts that major loading of PCB to Puget Sound come from surface water runoff. Highest PCB concentrations are in surface runoff from commercial/industrial areas, however, forested lands input largest PCB loads due to their large area. Given the currentestimated median loading to Puget Sound from all major pathways (7.7 kg/yr), overtime, natural attenuation is predicted by the PCB Box Model to reduce PCB levels in water, sediment and fish and wildlife. In the near-term, retrofits of developed landscapes should reduce inputs to sediment and fish and wildlife.the long-term success of retrofits depends on loadings from forested lands. 11

12 Due to time constraints, results will only be shownfor Englishsole from two urban areas. 12

13 At all urban bays except Sinclair Inlet, English sole showed no declining trend in PCBs, while at most non-urban locations they showed no increasing trend (West et al. 2011; poster and submitted paper to 2011 Salish Sea Ecosystem conference). We present results for two urban bays, Elliott bay and Sinclair Inlet. This slides depicts measured PCB levels in muscle tissue for Elliott Bay, an urban site along the Seattle waterfront, versus predicted PCB levels for English sole in Elliott Bay in 2020 assuming various loadings estimates (red dots; values taken from Table 18 in Pelletier and Mohamedali 2009; Observed PCB levels are increasing, despite some remedial actions that have taken place in the bay. Moreover, the observed observations are not on track to reach the 2020 predicted concentration assuming a loading of 10 kg/yr. The current median PCB loading estimate to Puget Sound from all major pathways is 7.7 kg/yr (Norton et al.2011; see Table 13; Thus,the 10 kg/yr loading approximates the current loading estimates (without additional strategies to reduce PCB loadings) and roughly represents the predicted natural attenuation strategy. 13

14 This slides depicts measured PCB levels in muscle tissue for Sinclair Inlet (near Bremerton and home to the Puget Sound Naval Shipyard). Sinclair Inlet was the only urban area where English sole exhibited a decline in PCBs, following significant and widespread reductions to control contaminant loads to the system (e.g., retrofits to stormwater discharges and combined-sewer-overflows), and restore/remediate contaminated sediments (e.g., dredging and capping of contaminated sediments in the early 2000s; slide presentation by Nancy Harney to SMWG; Sound/Workshop/Case/Study5- SinclairInlet.pdfhttp.) The local onsite and watershed source control, combined with the onsite sediment remediation also dramatically changed the sediment grain size. 14

15 Measured PCB levels in muscle tissue for Sinclair Inlet are already lower than the predicted PCB levels for English sole in Sinclair Inlet in 2020 assuming a load of that is approximately 10 times higher than the currently estimated median PCB loading. Predicted loadings are represented by red dots (values taken from Table 18 in Pelletier and Mohamedali 2009; Current loading is approximated by the 10 kg/yr value. This underscores the urban-focal nature of PCB contamination in Puget Sound. PCBs have remained low in English sole from non-urban areas over the past 20 years, suggesting that PCB loads are not increasing in sediments in those areas. Toxics control strategies (e.g. enhancements to wastewater treatment, stormwater retrofits, removal of contaminated sediments can result in reduction of PCB exposure in these organisms. 15

16 Unlike English sole, PCBs in Pacific herring, a pelagic (open water) species, were high throughout the main and southern Puget Sound basins. This has been reported elsewhere (West et al. 2008) and reflects the PCB-contaminated nature of Puget Sound s pelagic food web. PCB levels in herring have declined slightly in recent years in both the main and southern Puget Sound basins, although this trend may in part be explained by a concurrent decline in fish size (West et al. 2011, poster/submitted paper, 2011 Salish Sea Ecosystem Conference). Because of their pelagic nature, it is unlikely that PCB contamination in herring results directly from contaminated sediments. Their high exposure to PCBs and slight declining trend suggests an ongoing input to the pelagic food web in the water column, perhaps in plankton, at the lowest levels of the food web (see West et al. 2011; oral presentation, 2011 Salish Sea Ecosystem conference). 16

17 Large scale sediment remediation combined with local and watershed and uplandsite control can reduce PCB threat to benthic fish (and potentially juvenile Chinook salmon?). Whether these have an affect on PCBs in pelagic fish such and Pacific herring and sub-adult Chinook salmon in uncertain. Tweaking existing loadings models to better predict trends in PCBs in benthic fish may reveal whether clean-up of urban sites will improve the pelagic food web in the main and southern Puget Sound basins. Federal, state, tribal, and local cleanup activities are occurring throughout the Puget Sound region, including major cleanup locations in Bellingham, Bremerton, and Elliott Bay and the Lower Duwamish Waterway. Unfortunately, many of these efforts are very protracted. For example, in 2001 the Lower Duwamish was declared a Superfund, with 440 in-water acres identified for clean-up. To date, less than 10 acres have been remediated. The Puget Sound Action Agenda supports enhancement of these efforts. The Puget Sound Action Agenda also supports near-term actions for stormwater retrofits of developed lands and the evaluation of using Low Impact Development (LID) for newly developed lands. 17