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,

Background Question: what is TDS relationship to aquatic life? Challenge: TDS often with other stressors Approach: Evaluate TDS effects with other stressors minimized 2 Wayne Davis USEPA EcoAnalysts, Inc. E phemeroptera (Mayflies) P lecoptera (Stoneflies) T richoptera (Caddisflies)

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

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 HCO 3 - ) – SO 4 2-, Ca 2+, Mg 2+, Na +, K +, Cl – – Al, Cu, Fe, Mn, Se, Zn 4 R. J. Krenz

Site Selection & TDS Composition 5

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Results – Site Selection Non-TDS stressors not evident – Habitat comparable to reference – pH 6.6 – 8.5 – No obvious NPS Pollution Mean RBP Habitat Score RefTest

Reference Site (22  S/cm)Test Site (265  S/cm) Test Site (1,670  S/cm)Test Site (594  S/cm) 8

TDS Mean Ion Proportions 9 Reference Sites Mean TDS: 21 mg/L Test Sites Mean TDS: 406 mg/L

Test Site Mean Ion Concentrations 10

Test Site TDS Seasonal Variability TDS (mg/L) Fall 2008Spring 2009Fall 2009Spring n = n = n = n = 21 Means:

VASCI – TDS Associations 12 Analyses that follow should not be interpreted to indicate actual, potential, or suggested water quality criteria for TDS or component ions.

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 14 VASCI TDSSCCa 2+ SO 4 2- Mg 2+ K+K+ HCO 3 - Na + mg/L  S/cm mg/L TDS SC Ca SO Mg K+K HCO Na Cl Highly Correlated MeasuresMeasures Evaluated all correlations significant (p < 0.05)

VASCI Seasonality 15 Reference Sites FallSpring VASCI Score n=6n=9 Test Sites FallSpring VASCI Score n=27n= 39 Spring VASCI scores > Fall VASCI scores at test and reference sites

VASCI vs. TDS (LS Regression) 16 Model SC (  S/cm) TDS (mg/L)SO 4 2- (mg/L) Spring All - Year Fall OECs: VASCI = 60

VASCI vs. TDS (Quantile Regression) 17 Quantile SC (  S/cm) TDS (mg/L)SO 4 2- (mg/L) 90not sig OECs: VASCI = 60 Q90: 90 th quantile = 90% of data below line Q50: 50 th quantile = 50% of data below line Q10: 10 th quantile = 10% of data below line Q-value = probability of VASCI < 60

Observed Effect Concentrations (OECs) OEC = concentration where VASCI = Method Probability of VASCI < 60 at OEC (%) Model/ Quantile (%) SC  S/cm TDS mg/L SO 4 2- mg/L OLS RegressionFall All-Year Spring Quantile Regression Measured Values0All-Year All-Year1,3661,108849

Probability of VASCI < 60 19

Considerations OEC ≠ Toxicity TDS Composition: SO 4 2- and HCO 3 - dominant, Ca 2+ dominant cation VASCI Seasonality: Spring > Fall Variability of VASCI – TDS Association Variability of TDS (Temporal) 20

Field Sensitivity Distributions 21 Analyses that follow should not be interpreted to indicate actual, potential, or suggested water quality criteria for TDS or component ions.

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 (OEC X ) – OEC X = 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 Water Quality Parameter Proportion of Taxa Affected Model FallSpringAll-Year Specific Conductance (  S/cm) 5% % % TDS (mg/L) 5% % % SO 4 2- (mg/L) 5% % %

Orders 26 Mayflies most sensitive (E) Stoneflies least sensitive (P)

Considerations OEC X ≠ 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 TDS Temporal Variability 28 Data: DMME & VT ?

Questions? Study Sponsors: Virginia Dept. of Environmental Quality Virginia Dept. of Mines, Minerals, and Energy Powell River Project 29