What are Water Quality Standards for Toxicity, Whole Effluent Toxicity, NPDES Permit Limitations?

Water quality standards for toxics, whole effluent toxicity and National Pollutant Discharge Elimination System (NPDES) permit limitation are terms that represent key elements in the Environmental Protection Agency's program to implement congressionally mandated requirements pertaining to the discharge of toxics to the Nation's waters—its oceans, rivers, lakes and streams.

While toxics control is not new to water pollution control efforts, the current program represents a giant leap forward and involves areas of new science, technology, rules and regulations, all of which EPA is being compelled to develop and the States to adopt in a very short time-frame and with limited resources.

The result of this somewhat frenetic effort is a program surrounded by a cloud of uncertainty for the regulated ommunity. This article will describe some of the more significant areas of uncertainty with which municipalities will be confronted in attempting to comply with federal standards and mandates.

Are the national water quality criteria for toxics technically sound and suitable for adoption by the States and ERA?

The ERA water quality criteria were originally promulgated for use by the States as guidance for permit writers. Subsequently, use of these criteria form the basis for essentially all decision-making in water quality management and must, therefore, be technically sound if they are to protect the in-stream uses they were promulgated to protect.

During the ERA mandated triennial review of the water quality standards for the Commonwealth of Virginia, the Hampton Roads Sanitation District provided testimony—based on a review of ERA'S test data—which showed that the technical integrity of many of the ERA water quality criteria for metals was highly questionable and made their adoption as Virginia water quality criteria the subject of continuing debate. To date, the state of Virginia has not adopted ERA'S water quality criteria.

Our testimony showed that nearly all the studies used to develop the ERA water quality criteria for metals were the result of academic research by graduate students who used a variety of testing methods, most of which fail to meet current minimum ERA testing requirements.

Some researchers qualified their data warning that it should not be used for assessing the toxidty of the metal in the environment. Nevertheless, the data was used by ERA.

Testimony also showed that the statistical methods used to calculate the criteria frequently had more influence on the criteria than the toxidty of the chemical being tested. For example, removal of sensitive organisms from the data base generally resulted in more restrictive criteria.

Finally, testimony showed that ERA'S saltwater lead criterion was based on a data transcription error.

Are proposed new analytical tools, e.g., whole effluent toxidty testing, capable of accurately predicting the potential for adverse in-stream impacts?

Whole effluent toxidty testing (a test for toxidty in undiluted samples of water discharged from municipal sewage treatment plants) is widely recognized as a useful tool for assessment of the potential toxidty of a discharge. However, ERA'S use of whole effluent toxidty testing as pass/fail NPDES permit conditions with strict liability is questioned.

In other words, if a municipal facility fails one test, the city is subject to the range of sanctions in the Water Pollution Control Act. Concern exists about whether or not these tests have been sufficiently field-validated to determine if they accurately predict environmental impairment. In addition, the testing procedures themselves are still undergoing significant modification.

Legislation (H.R. 735) has been proposed which will allow the use of these tests as indicators of potential toxidty but without the strict liability associated with pass/fail effluent limitations. H.R. 735 bases liability on the diligence of the municipal discharger in identifying and controlling effluent toxidty. This approach will allow munidpal dischargers to resolve potential effluent toxidty problems without the threat of fines and/or imprisonment.

Will implementation of the requirements being promulgated under this program accomplish its goals and objec-

September 1991 / Illinois Municipal Review / Page 21

tives, that is, will measurable improvements in water quality occur?

Since the water quality criteria are themselves fundamentally flawed as previously indicated, the potential for the program meeting its environmental goals in a cost-effective manner is highly improbably.

Is treatment technology available to control the discharge of toxics? Is this technology affordable?

The vast majority of publicly owned treatment works (POTWs), were built for the purpose of achieving secondary treatment (biochemical oxygen demand and suspended solids removal) of municipal wastewater discharges and not for the removal of toxics.

A number of studies have indicated that in many POTWs, domestic (i.e., residential) sources of toxics, e.g., copper, are present in concentrations exceeding the EPA water quality criteria. Many of these plants will require development and application of sophisticated new treatment technologies. The cost of this new technology is unknown but is expected to be high.

Will NPDES effluent limitations for toxics be reasonable and capable of attainment?

At present, the trend among regulatory agencies is to issue pass/fail permit limits for toxics which are frequently near the analytical detection limit for the pollutant without taking into account irreducible sampling and analytical variability.

In order to illustrate this problem consider the situation in which a POTW collects a sample and has it analyzed by a reputable laboratory for a toxicant which has an analytical detection limit of 0.10 milligrams per liter for that toxicant. If the permit limit for that toxicant were 0.10 milligrams per liter and the lab reported a result of 0.12 milligrams per liter the POTW would be found in violation of its permit.

What if the same sample was analyzed by two other reputable labs and both reported results less than the detection limit? Is the POTW in compliance? In practice, three different laboratories can produce three different test results for three identical tests on the same water sample. However, the problem "natural analytical variability" raises with compliance is evident in such cases.

What should municipal officials do?

§ Do not accept permit limitations, terms or conditions which are neither reasonable nor attainable;

§ Do not accept permit limitations which you will knowingly violate despite assurances of regulators that they will exercise enforcement discretion;

§ Treat every alleged permit violation as a very serious matter and take all reasonable measures to ensure that its potential reoccurrence is minimized;

§ Familiarize yourself as much as possible with laws, rules and regulations pertaining to toxics control and how they might affect your jurisdiction;

§ Retain highly-qualified technical and legal consultants and/or staff who are experts in environmental law, rules and regulations; whole effluent bioassay testing; NPDES permit negotiations; and compliance monitoring and reporting.

§ Make certain that your laboratory uses EPA-approved analytical procedures, has an adequate QA/QC (quality assurance/quality control) program and has a demonstrated analytical capability;

§ Insist that your State regulatory agency and EPA promulgate water quality criteria which are technically sound;

§ Support funding of peer-reviewed research to enhance the credibility of the water quality criteria.

Page 22 / Illinois Municipal Review / September 1991