Regulation of “toxicity” in the State of California has generally been following 3 State Water Resources Control Board (State Water Board) precedential decisions that require dischargers under an NPDES permit, which have a demonstrated reasonable potential to cause or contribute to an instream exceedance for toxicity, to receive a narrative effluent limitation for chronic toxicity, along with a numeric trigger that requires accelerated monitoring and a special study to attempt to determine the cause of any toxicity. This practical process has achieved the goal of discovering, investigating, and in many cases resolving potentially toxic discharges for the better part of 15 years, and importantly, the methods used were approved under the federal Clean Water Act and U.S. EPA’s implementing regulations.
However, more recently, some regional water boards veered from the mandates of the State Water Board’s precedential orders, and instead imposed a U.S. EPA approach found in guidance, but not adopted regulations, which utilizes a Pass/Fail assessment using a bioequivalence approach called the “Test of Significant Toxicity” or “TST.” The State Water Board now intends to adopt this informal approach, itself an arguably underground “rule,” as new statewide policy. This action presents a number of legal and policy issues, as the draft policy differs from federally promulgated test methods for toxicity set forth in 40 C.F.R. Part 136 in the following substantive ways:
The draft policy also omits a substantive implementation plan in favor of increasing monitoring if toxicity is observed (the outcome or toxic presumption can change merely by doing additional tests (replicates)), which calls into question the validity of the initial results.
In sum, the draft policy appears to be a solution without an identified problem. As noted by the draft policy, many regions of the State have very little toxicity detected under the existing toxicity assessment approach, yet the draft policy proposes a new approach that could promote toxicity being identified more frequently, or improperly. Even more concerning is that the policy appears focused only on toxicity from large municipal wastewater dischargers, many of which have substantially upgraded their treatment systems to recycle water, and exempts the policy from applying to smaller dischargers and non-NPDES discharges. Thus, the policy does not achieve the goal of statewide consistency, and could result is disparate identification and enforcement of toxicity-related issues.
Comments on the draft policy are currently due December 7, 2018, although many have requested an extension due to the hundreds of pages of new information. A State Water Board workshop is currently scheduled for 11:00 a.m. on November 28th in Sacramento at the Cal/EPA building, and an adoption hearing is anticipated in the Spring of 2019. Commenters should consider encouraging the State Water Board to affirm use of the existing, mandated and proven Part 136 methods used in nearly all states in this country, and to suspend implementation of the TST until adopted by U.S. EPA as a federally approved method and/or a new ATP is approved authorizing use of the divergent approach proposed.