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TDS Effects on Aquatic Life in Virginia's Coalfield Streams

This study examines the levels of dissolved solids in central Appalachian coalfield streams in Virginia and their effects on aquatic life.

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TDS Effects on Aquatic Life in Virginia's Coalfield Streams

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  1. Levels of Dissolved Solids Associated With Aquatic Life Effects in Virginia’s Central Appalachian Coalfield Streams Tony Timpano Stephen Schoenholtz, David Soucek, Carl Zipper VirginiMarch 29a Tech , 2011

  2. Background EcoAnalysts, Inc. Wayne Davis USEPA EcoAnalysts, Inc. Ephemeroptera (Mayflies) Plecoptera (Stoneflies) Trichoptera (Caddisflies) Question: what is TDS relationship to aquatic life? Challenge: TDS often with other stressors Approach: Evaluate TDS effects with other stressors minimized

  3. Site Selection Iron Seep Sedimentation Systematic: GIS prescreen, ground-truth High-Quality Habitat Avoid Non-TDS Stressors:

  4. Data Collection • Field • RBP Benthic Macroinvertebrates • RBP Habitat • Temp, pH, DO, Cond. • Water grab samples • Fall 2008, Spring 2009, Fall 2009, Spring 2010 • Lab • Family & Genus “bugs”, VASCI • TDS • Alkalinity (for HCO3-) • SO42-, Ca2+, Mg2+, Na+, K+, Cl– • Al, Cu, Fe, Mn, Se, Zn R. J. Krenz

  5. Site Selection&TDS Composition

  6. 190 185 180 175 170 Mean RBP Habitat Score 165 160 155 Ref Test Results – Site Selection • Non-TDS stressors not evident • Habitat comparable to reference • pH 6.6 – 8.5 • No obvious NPS Pollution

  7. Reference Site (22 mS/cm) Test Site (265 mS/cm) Test Site (594 mS/cm) Test Site (1,670 mS/cm)

  8. TDS Mean Ion Proportions Reference Sites Mean TDS: 21 mg/L Test Sites Mean TDS: 406 mg/L

  9. Test Site Mean Ion Concentrations

  10. 1400 1200 1000 800 TDS (mg/L) 600 400 200 0 Fall 2008 Spring 2009 Fall 2009 Spring 2010 Test Site TDS Seasonal Variability Means: 566 n = 8 371 n = 16 485 n = 19 371 n = 21

  11. VASCI – TDS Associations Analyses that follow should not be interpreted to indicate actual, potential, or suggested water quality criteria for TDS or component ions.

  12. Analysis Methods • VASCI = multimetric index of benthic macroinvertebrate community integrity (0-100 pts) • Evaluate VASCI-TDS Relationship • Least Squares Linear Regression • Quantile Linear Regression • Observed Effect Concentration (OEC) = TDS concentration where VASCI = 60

  13. Correlations: Test Sites all correlations significant (p < 0.05) Measures Evaluated Highly Correlated Measures

  14. 80 VASCI Score VASCI Score 85 75 70 80 65 75 60 55 70 50 65 45 40 60 Fall Spring Fall Spring VASCI Seasonality Test Sites n=6 n=9 n=27 n= 39 Reference Sites Spring VASCI scores > Fall VASCI scores at test and reference sites

  15. VASCI vs. TDS (LS Regression) OECs: VASCI = 60

  16. VASCI vs. TDS (Quantile Regression) Q90: 90th quantile = 90% of data below line Q50: 50th quantile = 50% of data below line Q10: 10th quantile = 10% of data below line Q-value = probability of VASCI < 60 OECs: VASCI = 60

  17. Observed Effect Concentrations (OECs) OEC = concentration where VASCI = 60

  18. Probability of VASCI < 60

  19. Considerations OEC ≠ Toxicity TDS Composition: SO42- and HCO3- dominant, Ca2+ dominant cation VASCI Seasonality: Spring > Fall Variability of VASCI – TDS Association Variability of TDS (Temporal)

  20. Field Sensitivity Distributions Analyses that follow should not be interpreted to indicate actual, potential, or suggested water quality criteria for TDS or component ions.

  21. Field Sensitivity Distributions • Salt tolerance of individual benthic macroinvertebrate genera • Maximum Field Concentration (MFC) • MFC = highest conc. where genus observed • Cumulative Distribution Function (CDF) of MFCs • X% Observed Effect Concentration (OECX) • OECX = conc. affecting X% of genera

  22. Macroinvertebrate Genera • 97 genera • Excluded genera (37) • < 4 observations/genus (5% of 81 samples) • Genera not at reference sites • 60 genera used • Spring, Fall, All-Year models

  23. TDS FSDs

  24. X% Observed Effect Concentrations

  25. Orders • Mayflies most sensitive (E) • Stoneflies least sensitive (P)

  26. Considerations OECX ≠ Toxicity Small Sample Size = Few Taxa Method sensitive to rare taxa Truly rare taxa?  too few samples to know Temporal variability of TDS

  27. Further Research Needs ? Data: DMME & VT TDS Temporal Variability

  28. Questions? Study Sponsors: Virginia Dept. of Environmental Quality Virginia Dept. of Mines, Minerals, and Energy Powell River Project

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