Use of the Sediment Quality Triad: Where Ecology Counts Passaic River Symposium, 2014

Transcription

1 Use of the Sediment Quality Triad: Where Ecology Counts Passaic River Symposium, 2014 Brian Church, K. Tobiason, L. Saban, M. Johns, and R. Law

2 Sediment Quality Triad What is SQT? Weight of evidence approach using three lines of evidence: Sediment chemistry data Sediment toxicity data Benthic community data Sediment chemistry Sediment toxicity Risk Benthic community

3 Sediment Quality Triad Why use SQT approach? LOEs are combined to evaluate strength of the relationship between chemistry and toxicity and/or community-level effects Site-specific analysis with co-located data rather than comparison to SQVs Ecological data provide insight into current and post-remediation conditions Required/approved by USEPA for the LPRSA

4 Available Datasets Surface sediment chemistry 98 grab samples - randomly sampled, stratified by grain size, depth, and salinity Sediment toxicity 27 tests at salinity 5 ppt 71 tests at salinity < 5 ppt Benthic invertebrate community 50 samples downstream of RM samples upstream of RM 8.5 Sediment chemistry Sediment toxicity Benthic community

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6 SQT in an Urban Setting Ecology and habitat are key considerations What is an appropriate reference area? Similar habitat TOC, salinity, grain size, etc. Low contamination Do similar areas have similar benthic community structures (i.e., metrics)?

7 Urban Habitat Aquatic habitats in urban areas are impacted by many stressors: Sewage overflow and stormwater Permitted discharges Road/ urban runoff Invasive/ non-native species Altered hydrology, erosion, and sedimentation Dams, dredging, impervious surfaces, stabilized banks

8 Importance of Ecology Ecological data allows for site-specific evaluation of actual effects (AE=ME) rather than predictions based on thresholds Biological traits determine habitat associations: size, mobility, burrowing activity, longevity, tolerance of environmental stress, opportunistic behavior and adaptability, and reproductive and feeding strategies Potential for risk to benthic invertebrates can be defined as biological effects exceeding those observed in relatively uncontaminated urban reference areas

9 Stress and Succession

10 LPRSA BAZ (based on 2005 SPI survey) Majority of the biological activity occurs above the redox potential discontinuity layer RM 0 to RM 8.5: mean: 1.6 cm RM 8.5 to RM 17.4: mean: 1.9 cm (Germano & Associates 2005)

11 Community Structure Major Taxa

12 Community Structure Metrics Pielou s J Swartz's Dominance and Shannon-Wiener H' River mile Taxa richness SDI H' Taxa richness

13 Jamaica Bay Urbanized estuary Protected area with fully functioning saltwater marsh (National Parks Service) LPRSA TOC data generally within same range LPRSA and Jamaica Bay grain size data overlap Salinity overlap; LPRSA more dynamic range

14 SQT Weight of Evidence Reference Dataset Outliers in dataset? YES NO Remove outliers Identify and map individual locations that are below the reference area datasets Conduct one-tailed Mann-Whitney U test to detect significant differences between LPRSA and reference area datasets Summarize results, compare benthic impacts to the sediment chemistry LOE, and state conclusions and uncertainties

15 Comparing Benthic Communities Metrics at no LPRSA locations were below the range of the reference data 1,000,000 Abundance (per m 2 ) 50 Richness 3 Shannon-Wiener H' 100, , , Jamaica Bay LPRSA 0 Jamaica Bay LPRSA 0 Jamaica Bay LPRSA

16 Comparing Sediment Toxicity 120 Ampelisca abdita survival, 10-day Only 2 of 27 LPRSA locations were outside of the range of the reference data Ampelisca abdita survival (% of control) Jamaica Bay LPRSA

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18 SQT Conclusions SQT allows for ecologically relevant, site-specific analysis of co-located data to establish a better understanding between adverse effects and stressors Jamaica Bay provides a basis for comparison for estuarine LPRSA SQT data Potential for risk to invertebrates in the estuarine LPRSA is negligible to moderate relative to urban conditions