Sonia Nagorski, University of Alaska Southeast AWRA Conference, - PowerPoint PPT Presentation

Sonia Nagorski, University of Alaska Southeast AWRA Conference, September 17, 2019

Collaborators ➢ John Hudson, Independent Aquatic Ecologist, Juneau, AK. ➢ Eran Hood and Jason Fellman, University of Alaska Southeast ➢ John DeWild, David Krabbenhoft, and staff at USGS Mercury Research Lab, Middleton, WI ➢ Gina Ylitalo at Northwest Fisheries Science Center, Seattle, WA ➢ Undergraduate research assistants: Chris Salazar, Alex Whitehead, and Alex Botelho (UAS)

Salmon in the trees Increase • streamwater nutrient concentrations and biofilm abundance (Mitchell and Lamberti 2005; Chaloner et al. 2004, 2007; Tiegs et al. 2011; Hood et al 2019) • Benthic macroinvertebrate abundance (Minikawa 1997, Wipfli et al. 1998, Lessard and Merritt 2006) • fish growth and fat content (Wipfli et al. 2003, Heinz et al. 2004) • >4000 salmon-supporting streams in southeast AK • $1 billion annual industry

Salmon growth --Accumulate pollutants --Hg projected to double by 2050

Biovectors: Migrating animals may transport and focus pollutants From Blais et al. Environ. Sci. Technol. 2007

 Long-range atmospheric deposition of contaminants Average elemental mercury surface concentrations for July 2001 (ng/m3) GRAHM (Global/Regional Atmospheric Heavy Metals Model) simulation – Ashu Dastoor, Meteorological Service of Canada,Environment Canada Engstrom et al. ES&T, 2014  Chichagof Island lake sediment cores show 2.9 ± 0.5-fold increase since industrialization

What happens to deposited contaminants? Glacier Atmospheric deposition Hg Wetland POPs Geogenic Hg Upland Forest Toxic methylmercury Freshwater aquatic Salmon POPs Hg Intertidal Marine

Benthic macroinvetebrates above and below waterfall barrier at Peterson Creek 120 Peterson A 98.5 Peterson B 100 80.7 80 Total Hg (ng/g) 68.5 68.1 57.8 60 53.5 52.5 46.1 40 34.4 28.4 20 0 Baetidae Heptageniida Limnephilidae Ephemerelidae Chloroperlidae

Purpose of this study  To investigate the relationship between salmon spawner density and contaminant levels in streams ❖ To assess concentrations of marine-derived pollutants in various aquatic components (water, sediment, biofilm, macroinvertebrates, juvenile fish) ❖ Measure upstream (salmon absent) vs. downstream (salmon present) ❖ Compare across streams with varying spawnerdensity

Study sites: 5 Juneau- area watersheds Bridget Cove Cr. Peterson Cr. Shrine Cr. Salmon Cr. Fish Cr.

Sampling for mercury and POPs Stream water: filtered and Hg Biofilm on incubated leaves Streambed sediment particulate fractions Juvenile/resident fish Hg + POPs Benthic macroinvertebrates + Fish density counts 1-3x/ week

Results  1. Salmon spawnerdensities varied among streams Leaf incubation Sediment samples Water samples Fish, BMI samples

Results 2. Contaminant concentrations were higher in the lower reaches where salmon spawners were present (one-way paired t-test , p <0.05) for: • %methyl-Hg in filtered water and in biofilm • methylmercury in Heptageniidae mayfly larvae • Methylmercury in streambed sediments Methyl-Hg in Heptageneiid larvae Biofilm+leaves %Hg as MeHg %Filtered Hg as MeHg Bed sediment Methyl-Hg 35 0.7 20 140 % methyl-Hg of total Hg in biofilm+leaves Methyl Hg in bed sediment (ng g -1 dw) Upstream (Site A) Upstream (Site A) 30 Downstream (Site B) Downstream (Site B) 0.6 120 15 25 Percent methyl-Hg -1 dw) 100 0.5 20 Methyl-Hg (ng g 10 80 0.4 15 60 5 10 0.3 40 5 0 0.2 20 0 0.1 0 Fish BCC Salmon Fish Peterson BCC Shrine Salmon Peterson Shrine h C e n n o s o C n i m F s r i B r h l e a S Salmon Fish Peterson BCC Shrine t S e P No spawners-------------------------- → highest No spawners---------------------------- → highest No spawners--------------------------- → -highest No spawners--------------------------- → -highest spawner density spawner density spawner density spawner density

2. Contaminant concentrations were higher in the lower reaches where salmon spawners were present (one-way paired t-test , p <0.05) for: • ΣHCBs, ΣDDTS, Σchlordanes, and ΣPCBs in fish tissues Fish tissues: chlordanes Fish tissues: sumPCBs Fish tissues: sumDDTs Fish tissues: HCB 1.2 3.0 1.2 6 1.0 2.5 5 1.0 sum chlordanes (ng/g) sum DDTs (ng/g) sum PCBs (ng/g) 0.8 2.0 4 HCB (ng/g) 0.8 0.6 1.5 3 0.6 0.4 1.0 2 0.4 0.2 1 0.5 0.0 0 0.0 0.2 Salmon Fish Peterson BCC Shrine BCC BCC Fish BCC Shrine Salmon Fish Peterson Shrine Salmon Fish Peterson Shrine Salmon Peterson • Several other POPs (dieldrin, oxychlordane, and ΣBDEs), where present, were higher at the lower sites. • The POPs data indicate a stronger marine-derived influence than the Hg, which has geogenic sources as well.

 3. Total and methyl-Hg in biofilm (via incubated leaf packs) were s trongly correlated with  aqueous total Hg  aqueous methyl-Hg  spawner density,  indicating their potential usefulness as a passive integrator of MeHg and monitoring/assessment tool. Total Hg in biofilm vs Filtered water Methyl-Hg in biofilm vs avg salmon density 6 1.6 Mean salmon density (fish/m2) 1.4 R² = 0.7227 Filtered water (ng/L) 5 1.2 R² = 0.7434 4 Alder leaf packs, 1 3 0.8 incubated for biofilm 0.6 2 growth, resulted in 0.4 1 particularly 0.2 0 0 consistent spatial 0 10 20 30 40 0 2 4 6 8 10 patterns Total Hg in biofilm (ng/g) Methylmercury in biofilm (ng/g)

 4. Other analytes followed this trend but did not pass statistical tests (likely due to small sample size (n=5)of individual streams.  For example, unfiltered total and methyl-Hg were consistently higher (up to 20x) in the lower reaches except for in Salmon Creek (no salmon present) In the two streams with the Total Hg (unfiltered water) Methyl-Hg (unfiltered water) 10 3.0 highest spawner densities, filtered MeHg was 10 to 11-fold higher in 2.5 8 the lower stream reach and made up 5-33% of the total Hg. 2.0 -1 ) 6 (ng L 1.5 1.0 4 0.5 2 0.0 0 Salmon Fish Peterson BCC Shrine Salmon Fish Peterson BCC Shrine

5. Comparison of concentrations relative to health criteria and other sites nationwide shows: • exceedance of 30-day fish-eating wildlife criterion for total Hg occurred in 3 of the 5 streams, especially in the salmon-supporting reaches. • unfiltered methyl-Hg in water is among the highest in the nation at Shrine B, the reach with the highest salmon density Total Hg (unfiltered water) Methyl-Hg (unfiltered water) 10 3.0 2.4 ng/L= Within the top 1% % 2.5 8 of MeHg in streams and lakes in 2.0 the U.S.A. and 12x higher than -1 ) 6 the national mean ( n =336; (ng L 1.5 Scudder et al. 2009). 1.0 4 Less than 1 km upstream, with few salmon, the concentration 0.5 was only 0.18 ng/L). National average 2 30-day standard for 0.0 fish-eating wildlife 0 Salmon Fish Peterson BCC Shrine Salmon Fish Peterson BCC Shrine

Methylmercury bioaccumulates and biomagnifies in aquatic ecosystems Methylmercury concentrations in aquatic organisms increase with increasing methylmercury concentrations in water and with increasing trophic level. Fish at the top of the food web tend to have the highest concentrations of methylmercury. (From: USGS Circular 1395 (Wentz et al. 2014).

• Half the samples from resident/rearing fish exceeded 100 ng/g, which is the level of concern for fish-eating mammals (Fig.9) • Only exceedance of human health criteria was for fish tissues in lower Shrine Creek. Fish tissue-total Hg 400 total Hg concentration (ng g -1 dw) 350 EPA protection of 300 Human health 250 200 150 Concern for 100 fish-eating mammals 50 0 Fish BCC Salmon Peterson Shrine

Conclusions • Contaminant loads appear to be measurably influenced by the presence of salmon spawners and carcasses • Mercury sources include a combination of spawner, geogenic, and atmospheric influences. • POPs occurrences in fish tissues were consistently enhanced in lower stream reaches, indicating a dominant marine source • inconsistent with Hg, which was also present in upper reaches • Comparisons of concentrations in higher trophic organisms is challenging due to differences in presence (by species, age) above and below barriers. • Passive integrators (e.g. incubated leaf packs) should be further explored as a meaningful monitoring tool in streams • Implications: • As salmon accumulate contaminants in the ocean and return to streams to spawn, they can have a measureable effect on contaminant concentrations in stream ecosystems. • Contributions by salmon should be better defined and monitored into the future as marine contaminant levels change

Thank you! Questions?

Acknowledgments Funding: INBRE John Hudson, Independent Aquatic Ecologist, Juneau, AK. John DeWild, David Krabbenhoft, and staff at USGS Mercury Research Lab, Middleton, WI Gina Ylitalo and Bernadita Anulacion at Northwest Fisheries Science Center , Seattle, WA Eran Hood and Jason Fellman, University of Alaska Southeast Undergraduate research assistants: Chris Salazar, Alex Whitehead, and Alex Botelho (UAS)