Significant or De minimis Water Quality Impacts

 

 Nowhere in the Clean Water Act or in federal regulations are allowances made for so-called “de minimis” or insignificant degrees of degradation, by which water quality may be lowered without antidegradation review and justification by economic and social necessity.  We recognize that the EPA has approved such measures and provided guidance for their implementation but find no legal support or justification for these approvals.

 

The EPA’s primary justification for allowing de minimis amounts of degradation is that this procedure “allows States and Tribes to focus limited resources where they may result in the greatest environmental protection”

 but, by this reasoning, the EPA seems willing to replace the judgment of Congress with ad hoc and relatively unbounded value judgments by State agencies.  At the same time, the EPA acknowledges that “States or Tribes that define a high threshold of significance may be unduly restricting the number of proposed activities that are subject to a full antidegradation review”

 but the Agency has failed to define what it considers an appropriate “threshold.”

 

The Supreme Court addressed this issue in Arkansas v. Oklahoma, 503 U.S. 91 (1992).  In that case a new sewage treatment plant in Arkansas, which was to discharge effluent that would flow downstream through a series of three creeks for 17 miles, enter the Illinois River, and then flow another 22 miles before crossing the border into Oklahoma.  The State of Oklahoma’s WQS required that “no degradation” of the upper Illinois River could be permitted.

    

 

An Administrative Law Judge had first upheld the permit, finding that there would not be an “undue impact” from the new discharge to a portion of the River in Oklahoma that was already impaired; that there would be no more than “a mere de minimis impact”

 on the downstream State’s waters.  The EPA’s Chief Judicial Officer also upheld the permit but ruled that a proper interpretation of the federal regulation required a more protective standard; that where the prediction of an impact was merely theoretical but was “not expected to be actually detectable or measurable,” the permit should not be denied on that basis.  The Supreme Court ruled that EPA’s interpretation of the CWA and the regulation was not arbitrary and capricious and upheld the permit.

    

 

Given that discharges permitted under Virginia’s guidance certainly results in detectable negative impacts on receiving waters, under critical conditions, the standard applied by EPA and upheld by the Court in Arkansas v. Oklahoma provides no support for the policy that is embodied in Virginia’s current WQS and the guidance that supports it.

 

Below we address the lack of technical support for the particular “significance” thresholds described in DEQ guidance memoranda but we would submit that similar technical concerns make the designation of any de minimis threshold improper.  To assume that any level of degradation from the increase of a particular pollutant in a waterbody is insignificant would require an analysis not just of “assimilative capacity” for that pollutant but of a range of issues to include synergistic effects, fate and transport, bioaccumulation, and bio-concentration, to name just a few.  

 

The Virginia policy allows a discharge to consume up to 25% of any available assimilative capacity between baseline conditions and a numeric criterion, when the criterion relates to pollutants controlled for toxicity to aquatic life.

  For criteria designed to protect against toxic harms to human health, the discharge may consume up to 10% of the available assimilative capacity.

  

 

This blanket approach to whole groups of pollutants is inappropriate and is not supported by any analysis provided by the State or by EPA.  This practice is especially problematic because the nature of the impacts from increased amounts of various contaminants can be very different.  For example, there is a fundamental difference between the ways carcinogens and non-carcinogens are believed to affect human health.  Carcinogens are regulated based on an “assumption of non-threshold effects (i.e., no safe level exists below which any increase in exposure does not result in an increased risk of cancer) for carcinogens.”

      

 

So, in contrast to non-carcinogens, any increase in concentrations of these substances to which humans are exposed is predicted to cause an increased risk in the incidence of cancer and, potentially, mortality.  Further, the fact that different carcinogens have different cancer slope risk factors (also known as “potency factors”)

 indicates that the rates at which the increased concentrations of various chemicals increase the threat of tumors is predicted to be extremely variable. 

 

Where EPA has approved significance thresholds in State antidegradation implementation procedures, a wide variety of approaches have been applied and we find no justification in any support documents that justifies these differences.  “Significance tests range from simple to complex, involve qualitative or quantitative measures or both, and may vary depending upon the type of pollutant (e.g., the approach may be different for highly toxic or bioaccumulative pollutants).”

 

 

 

By failing to even acknowledge factors such as bioaccumulation, bioconcentration, synergistic or additive effects, or many other pertinent technical factors, Virginia’s approach fails to consider important information that is widely available and, thus, its establishment of the significance threshold in the antidegradation implementation procedures (and by reference in the WQS regulation) is arbitrary and capricious.  

 

The State of Virginia has provided several additional significance thresholds for particular parameters (dissolved oxygen, pH, and fecal coliform bacteria), in addition to the general approach discussed above.  Again, these methods, by which water quality degradation may be allowed without a full antidegradation review, are without technical or logical support.

 

The Virginia guidance states: that, for pH, changes will be considered insignificant where “pH is maintained within the 6.0 to 9.0 range.”

  However, a change in the pH of a waterbody from one end of the prescribed range could cause very serious water quality problems.  A change on the pH scale from 7 standard units (“SU”) to 9 SU represents a difference in hydrogen ion concentration of two orders of magnitude - a far from insignificant shift and one that could affect aquatic life quite drastically.  The implication of such a change is important for a number of reasons.  For example, the unionized form of ammonia, which is especially toxic to fish and other organisms, could rise by over three orders of magnitude with such a pH change.

 

 

Requirement for Numeric Nutrient and Sediment Criteria

 

Virginia and other states are required by Section 303(c) of the CWA to adopt water quality standards for waters of the United States within their applicable jurisdictions. Section 303(c)(2)(A) and EPA’s implementing regulations at 40 CFR part 131 require, among other provisions, that State water quality standards include the designated use or uses to be made of the waters and the criteria necessary to protect those uses.  EPA’s regulations at 40 CFR § 131.11(a)(1) provide that States shall “adopt those water quality criteria that protect the designated use” and that such criteria “must be based on sound scientific rationale and must contain sufficient parameters or constituents to protect the designated use.”

 

 

Virginia has no numeric criteria for nutrients in “free-flowing” streams upstream of the coastal plain areas nor any widely applicable numeric criteria for sediments/turbidity.  The “General” or narrative criteria require the State to control “substances that produce color, tastes, turbidity, odors, or settle to form sludge deposits; and substances which nourish undesirable or nuisance aquatic plant life”

 and prohibits pollution that will “interfere directly or indirectly with designated uses of such water or which are inimical or harmful to human, animal, plant, or aquatic life.”

 

 

As described above, we believe these narrative criteria can and must be implemented much more widely and stringently.  However, even the most faithful implementation of the narrative strictures cannot fully protect our waters.  By the time undesirable or nuisance aquatic life has emerged in a waterbody or sludge deposits have formed, significant damage has been done.  Our legally-mandated goal  is to protect water quality, not just to react once that quality is degraded.  Numeric criteria are necessary to allow us to check for problems in streams before those problems become dire.  Further, they provide a more certain basis for regulatory controls in discharge permits, which, even if applying narrative criteria have to derive site-specific numerical limits and in-stream wasteload allocations (“WLAs”).  

 

Over the many years now since the modern Clean Water Act was passed in 1972, nutrients and sediments have always been major causes of impairments state-wide and nation-wide.  And the excuse for failing to devise numeric criteria has been, to characterize it succinctly, “it’s too difficult.”  In fact there are an abundance of sources that should instruct us in adopting our own criteria for these substances:  EPA guidance, including ecoregion-based nutrient criteria recommendations; the reports of advisory committees and staff investigations organized by the DEQ; examples set in other states; and many others. 

 

We cannot fail to acknowledge the fact that one of the largest, most expensive, and most heralded efforts to reverse water pollution impacts - the fight to clean up the Chesapeake Bay - focuses almost exclusively on the need to control sediments and nutrients.  To continue to delay the establishment of numeric criteria is indefensible.

 

Requirement for Criteria to Address Flow Impairments

 

In large part the reasons that should compel Virginia to adopt numeric criteria for nutrients and sediments should also compel the State to incorporate flow provisions into the WQS, and we need not elaborate to a great degree here.  The State is well aware of the problems caused by flow alterations.  It addresses them in 401 certifications for hydropower projects licensed by the Federal Energy Regulatory Commission and for water supply reservoir construction proposals.  It has worked hard to incorporate provisions into the various stormwater management programs to protect stream environments from extreme and flashy runoff and the impacts of impervious watersheds.  

 

At the same time new flow-induced damages are inflicted on Virginia waterbodies every day.  Some of those damages can be addressed through existing regulatory programs - others cannot.  Regardless, it is important that Virginia have criteria by which to judge flow-based impairments in its water quality standards, that it routinely monitor to see where these impacts are occurring, and that it implement existing procedures or develop new ones wherever necessary to control this very damaging cause of pollution.

 

Thank you for considering our comments and please contact at Jeff Kelble or Robin Broder if you have any questions about this submittal. 

 

Sincerely,

Jeffrey D. Kelble

Shenandoah Riverkeeper

Potomac Riverkeeper Inc.

P.O. Box 405

Boyce, VA 22620

Phone: 540-837-1479

Email: Jeff@shenandoahriverkeeper.org

 

 

 

 

 

Robin Broder

Vice President

Potomac Riverkeeper, Inc.

1100 15^th Street, NW, 11^th floor

Washington, DC 20005

202-222-0706

robin@potomacriverkeeper.org

 

 

**Please note that we will supply a version of these comments that includes citations to the sources accessed for the comments in another form, since we were unable to include those here.