Total Dissolved Solids: The Challenges Ahead. US EPA Region 3 Freshwater Biology Team Wheeling, WV. FBT Members Amy Bergdale, Frank Borsuk, Kelly Krock, Maggie Passmore, Greg Pond, Louis Reynolds Assist the states in methods development, bioassessment, biocriteria
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US EPA Region 3
Freshwater Biology Team
Amy Bergdale, Frank Borsuk, Kelly Krock, Maggie Passmore, Greg Pond, Louis Reynolds
Assist the states in methods development, bioassessment, biocriteria
Assist EPA R3 in use of biological data
WQS, monitoring, TMDLs, NPDES, superfund, etc.
Perform special studiesFreshwater Biology Team, EPA R3, EAID, OMA
K+ > HCO3- =Mg2+ > Cl- > SO42-
D. magna or
Illinois states that “Sensitive organisms reside in receiving streams with sulfate concentrations of 2,000 mg/L.”
Effluent Dominated Streams
E. Fleek, NC DWQ
Mayflies represent ~25-50% of Abundance; ~1/3rd biodiversity
In natural, undegraded Appalachian streams
(Eastern Kentucky Coalfields)
Note: strong nonlinear “threshold” response
(West Virginia southern coal fields)
Is aquatic life in small Appalachian streams more sensitive to TDS pollution than that in midwestern streams?
% Sensitive Mayflies
What aquatic life is found in the midwest? Perhaps more TDS-tolerant invertebrates?
Isonychia, Tricorythodes, Baetis, Caenis
% Tolerant Mayflies
Chronic effects were detected in samples with field conductivity >1800 µS/cm.
There is NO dilution capacity in these streams.
Estimated conductivity at EC25 % ranged from 448-1243 with an average of 820 µS/cm.
This range is slightly higher than where we see effects with resident biota.
Ref for GLIMPSS
Not tox tested
All sites were rated impaired using the genus level GLIMPSS (<66) , which directly measures aquatic life use impairment. The resident biota are more sensitive than the WET surrogate, C. dubia. Can’t use C. dubia alone to express “safe” thresholds, but it can be used as an indicator of the more toxic discharges.
Over 90% when
Cond > 500
Probability of impairment
Split Variable PRE Improvement
1 SULFATE 0.726 0.726
2 Mn DISS 0.758 0.032
3 CONDUCTIVITY 0.819 0.062
4 SULFATE 0.855 0.036
5 ZINCTOTAL 0.872 0.017
6 MAGNESIUM 0.882 0.010
All Ions, Metals, pH, Hardness
We have not reviewed any bioassessment data from Iowa.
R3 Empirical examples suggest impairment at sulfate 200-400 mg/l
(EPA Criteria/State WQS)
(Identify Impaired Waters)
Monitor and Enforce
(including instream bioassessments)
(Point Source, NPS)
of WQS for Specific Waters
Define and Allocate
Review literature for TDS
Develop empirical datasets between TDS and aquatic life
Acute and chronic tests with mining effluent and reconstituted salts and surrogate organisms (e.g. C. dubia)
USGS Columbia Lab, Duluth EPA Lab
Preliminary Data…Ongoing Research - Surrogates
Hassell et al 2006
Deploy insects in situ – sample individuals in a time course
Measure growth, metal and electrolyte content, subcellular compartmentalization of metals
Explain any differences in metal tolerance, bioaccumulation and toxicity
Monitor oxygen consumption, osmoregulatory status and Adenosine triphosphate (ATP) levels
Characterize “energetic costs” to living in high conductivity
Provide information on whether metal uptake is contributing to impairment
Provide information on mechanism for TDS impairment
North Carolina StateOngoing Research - Natives
Buckwalter et al, 2007