1. Selenium: The Curse of the West
2015 GEI VP Planning Meeting
Succession
Selenium: The Curse of the West
Steve Canton
WESTCAS June 21, 2017

2. Selenium Criteria history: overview from a westcas perspective

3. Selenium in the Arid West
The West has large areas of underlying marine shales that results in elevated selenium in surface water
Studies on fish populations have indicated that fish seem to have adapted to elevated selenium, and have healthy reproducing populations
Water is also limited – with approximately 90 percent ephemeral or intermittent streams
Populations limited by habitat, not water quality

4. First concerns with “what is appropriate criteria
First concerns with “what is appropriate criteria?” raised by those in the Arid West
1987 EPA chronic criteria – 5 µg/L (acute= 20 µg/L)
Colorado initially refused to adopt
1995 – Many dischargers in Colorado predict having difficulty meeting selenium criteria
Began studies on the issue prior to state adoption of EPA criteria by Colorado
Result was footnote to standards “selenium is a bioaccumulative metal and subject to a range of toxicity values depending upon numerous site specific variables”
1997 – Kennecott Selenium Symposium in Utah
to discuss Se issues in the west
1998 – EPA held a Peer Consultation Workshop
to assess the state of the science on selenium toxicity
concluded tissues likely best predictor, not water or sediment
1999 – USFWS recommended 2 µg/L
Adopted by Arizona

5. EPA Se criteria repeatedly revised over time
2002 and 2004
Draft tissue-based criterion of 7.9 mg/kg
Never finalized
2014
Draft tissue-based criterion – for public comment
2015
Second draft of tissue-based criterion – for public comment (producing yet another draft is a first for EPA)
2016
Final tissue-based selenium criterion
Draft implementation guidance – still pending

6. EPA 2016 selenium criteria

7. 2016 EPA Final Criteria Tissue-based Criteria Element
15.1 mg/kg egg/ovary
8.5 mg/kg whole body
11.3 mg/kg muscle tissue
Default Water Column Criteria
Monthly average - chronic
1.5 µg/L lakes
3.1 µg/L rivers
Acute – not included
“Intermittent Criteria” –simply an equation based on number of days/month exceeding default value

8. Derivation of EPA Default Water Column Criteria
Modeled – using sediment, algae, invert, and fish
Used site-specific data for 26 lake / 39 stream sites
The data set is very limited
With most data well over 20 years old
GEI tested the calculation with additional site- specific stream data from Colorado
Resulted in lotic value of 5.8 µg/L
Arid Western states should review EPA’s water column numbers and develop more state-specific water column values

9. EPA Draft implementation guidance

10. Draft Implementation Guidance
Four documents
Technical Support for Adopting and Implementing EPA’s 2016 Selenium Criterion in Water Quality Standards
Technical Support for Fish Tissue Monitoring for Implementation of EPA’s 2016 Selenium Criterion
FAQ’s: Implementing WQS that Include Elements Similar or Identical to EPA’s 2016 Selenium Criterion in Clean Water Act Section 402 NPDES Programs
FAQ’s: Implementing the 2016 Selenium Criterion in Clean Water Act Section 303(d) and 305(b) Assessment, Listing, and TMDL Programs
What do these documents say?
More importantly, how could they be improved for the Arid West?!

11. 1) Tech Support for Adopting and Implementing in WQS
EPA provides only two scenarios for when SSS are appropriate
Water column exceeded – fish tissue attained
Water column attained – fish tissue exceeded
No option for situations in which both are exceeded, as is common in the Arid West due to native geology
EPA modeling (using mechanistic or bioaccumulation approaches) only derive SS water column criteria
SS tissue criteria are also necessary
Example: St. Charles River near Pueblo
Existing SSS of 173 µg/L (ac) and 50 µg/L (ch) based on ambient conditions
Tissue concentrations also elevated – up to mg/kg (WB), yet fish communities healthy and unaffected
Our data suggest modeling does not work in areas with naturally elevated selenium in the Arid West

12. 1) Tech Support for Adopting and Implementing in WQS
EPA allows use of recalculation procedure for site- specific tissue criteria
Difficult to apply since Se database is limited
Deletion of “non-resident” fish would likely eliminate over half the database for most arid west streams!
Likely result would be defaulting to the lowest chronic value for species present?
Most sensitive species in database is White Sturgeon
No sturgeon in Arid West streams
Simple option would be for default tissue criterion after excluding sturgeon?

13. 3) FAQs: Implementation in 402 NPDES Programs
Reasonable potential analysis
Ultimately based on water column, even if fish tissues are meeting the criterion
We believe this is inappropriate – water column criterion is based on modeling, not actual toxicity data
If tissue overrides water in the criteria document, it should override for RP
Tissue data should be used to determine RP in systems in steady-state, but permitting programs not ready for something “this radical”!

14. 3) FAQs: Implementation in 402 NPDES Programs
Acute limits in permits needed?
Some permit writers think so…
If necessary - an option would be to use the acute criteria from EPA’s 2004 draft Se criteria document
Separate criteria for selenite and selenite, with sulfate modifier
In western states elevated selenium coincides with elevated sulfate, explains the healthy populations in high Se regions
Biokinetic modeling suggests this approach would still be protective of the chronic tissue criterion
Still, you don’t have to have an acute limit
Many permits only require chronic WET, for example

15. 4) FAQs: Implementation in 303(d), 305(b) and TMDL programs
Fishless streams – common in Arid West states due to limited water and ephemeral or intermittent systems
Defaults to water column value
We do not agree – criterion is intended to protect fish.
If fish are not present, the default water value is overprotective
Better approach - collect tissues in the nearest downstream location with fish
Alternatively, base attainment on invertebrate tissues (i.e., protect the attainable use) using values in criteria document

16. So, what does it all mean for WESTCAS members ?!
The new EPA selenium criteria have the potential to be beneficial for Arid West states
But, unless significant changes are made to the implementation guidance, selenium will continue to be the
“Curse of the West”!!

17. Questions?