Study goals
Stakeholders — including municipal stormwater permittees — in Western Washington want to know the current status of Puget Sound nearshore health. They also want to know if stormwater management actions are collectively protecting and recovering nearshore habitat and wildlife.
Study design
Puget nearshore monitoring studies follow probabilistic survey design. Randomly selected sites are located in the Puget Sound nearshore along urban growth area shorelines – areas presumed to be most affected by stormwater runoff. Since the first three monitorings in 2014 - 2020, the study design was expanded beyond just the UGA to the entire nearshore and stratified to better answer regional status and trend questions.
Mussels, filter feeders, are a good tool to measure the extent of pollutants present in the nearshore. The objectives of the SAM Mussel Monitoring survey are to; 1) characterize the spatial extent of contamination to which nearshore biota residing inside the UGA sampling frame may be exposed, and 2) track changes in tissue contamination over time inside the UGA sampling frame. A total of 33 randomly selected sites with three least-disturbed sites across the whole Puget Sound nearshore and three baseline samples are monitored biannually.
Study findings
The winter 2019/2020 monitoring survey was the third survey under this ‘UGA’ study design and provides the first opportunity to evaluate changes in contamination of nearshore biota residing inside the urban growth areas (UGAs) of Puget Sound. The other two surveys were conducted in winters of 2015/2016 and 2017/2018. Over the course of the 4 years from 2015-2020:
- The spatial extent of the impacted urban nearshore remains unchanged in Puget Sound; polycyclinc aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) are correlated with the urban metrics, such as the percentage of impervious surface cover in the region.
- PAHs, PBDEs, and DDTs had significantly lower central tendency concentrations in mussels from this third survey (2019-20) than the prior two surveys.
- PCB accumulation appears to be spatially gradual throughout the UGA shoreline, without attributable hot spots across the UGA. In contrast, PAHs contamination is relatively low in the study area with a few high contamination sites, possibly indicating point sources.
- The declining PBDEs concentrations but stable PCBs concentrations were congruent with the temporal pattern in two other WDFW-TBiOS indicator species.
This represents the final survey under the ‘UGA design’ and all future SAM mussel monitoring surveys will be done under the new design that expands the nearshore study frame from UGA’s only to the entire Puget Sound nearshore. The 2021-22 survey will include a subset of the sites (15) sampled under this ‘UGA design’ to track changes in these locations.
Washington Department of Fish and Wildlife led three rounds of caged mussel monitoring in 2015/2016 (Round 1), 2017/2018 (Round 2), and 2019/2020 (Round 3), to assess bioaccumulation of pollutants from the water column along the urban marine shoreline in Puget Sound.
Study questions
This project is designed to tell us mussel bioaccumulation levels related to urbanization in the region, and to answer how mussel tissue bioaccumulation levels change over time.
The same 38-41 nearshore sites within the urban growth area (UGA) in Puget Sound were visited three times (round 1 to round 3).
Key deliverables and documents
Study findings
The concentrations of many organic contaminants, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were highly correlated with the urban metrics, such as the percentage of impervious surface cover in the region.
Round 1
Round 2
Round 3
The Washington Departments of Health and Ecology's Beach Environmental Assessment Communication and Health (BEACH) program compiled existing fecal indicator data in Puget Sound nearshore areas.
Study objectives
This study aimed to assess current bacteria levels in Puget Sound nearshore areas along the urban shoreline, and to assess spatial or temporal data gaps in coverage between existing marine bacteria monitoring programs.
Study findings
Diverse data sets from entities with different sampling goals and methodology showed diverse results. For example, ambient monitoring programs had lower bacteria levels whereas targeted programs that focus on monitoring storm events or source identification had higher bacteria levels. The existing bacteria monitoring programs might provide sufficient information to track bacteria levels in Puget Sound.
Marine nearshore sediments were sampled at approximately one fathom depth along the urban nearshore in Puget Sound during the summer of 2016, at many of the same sites as the SAM mussels study.
Study objectives
The goals of this study are to assess chemical concentrations in the Puget Sound urban nearshore sediments and, in the long term, to monitor how nearshore health changes over time.
Study findings
The concentrations of metals and organics in nearshore sediment were relatively low in the Puget Sound Urban Growth Area (UGA) nearshore. Natural variables, such as ocean currents movement appear to govern spatial variation of sediment quality in the area. Lead, copper, and zinc concentrations were only weakly related to urban land use metrics.