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

Selenium Criteria history: overview from a westcas perspective

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

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

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

EPA 2016 selenium criteria

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

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

EPA Draft implementation guidance

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?!

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 105.9 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

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?

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”!

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

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

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”!!

Questions?