The U.S. Environmental Protection Agency seeks comment by June 7 on a proposed rule to approve dozens of new and updated analytical methods for drinking water and wastewater.
These include 28 drinking water methods developed by ASTM International and 64 drinking water methods in Standard Methods for the Examination of Water and Wastewater, jointly published by AWWA, the American Public Health Association and the Water Environment Federation.
Published in the April 6 Federal Register, the proposed rule approves four new vendor-developed methods for drinking water including a gamma spectrometry method from the Environmental Resources Center at Georgia Institute of Technology. This method simultaneously analyzes for both radium 226 and 228 and also promises to cut in half the related labor and waste-disposal costs.
The rule also would add a new USEPA method (327.0) for measuring chlorine dioxide disinfectant residuals in drinking water and withdraw the Syngenta AG-625 immunoassay method for atrazine based on evidence showing interferences due to chlorine and chlorine dioxide that generate false positives and elevated atrazine levels.
Hailed by EPA as promoting consistency between water and wastewater compliance monitoring programs and providing analysts increased flexibility in selecting methods, the rule also proposes to approve alternate test procedures for detecting cyanide in water and wastewater samples and assessing acute toxicity of wastewater samples.
The two methods for detecting total cyanide include a microdistillation method from Lachat Instruments and an automated procedure developed by Kelada Automated Test Methods.
The Microtox acute toxicity test, a Whole Effluent Toxicity alternate method developed by Strategic Diagnostics, assesses toxicity by measuring the bioluminescent reaction of a dosed bacteria. EPA is proposing to approve the method to screen wastewater discharges to freshwater for acute toxicity.
The rule also reproposes several methods first proposed in 1995 and in widespread use despite never having been formally approved, including EPA Method 218.6, an ion chromatography method for measuring hexavalent chromium in drinking water and ground water, and EPA Method 300.0, an ion chromatography method for analyzing inorganic ions in water and wastewater samples.
Analysis of inorganic ions in water and wastewater would also be permitted under the proposal using an alternate method (ASTM Method D6508) developed by Waters Corp. that uses capillary ion electrophoresis and a chromate electrolyte.
Finally, the proposal also seeks comment on a guidance protocol for evaluating microbiological alternate test procedures. The protocol was released in 2003 in conjunction with a July 21 rule that promulgated methods for analyzing microbial contaminants in ambient waters.
Also, in regard to the approved tests published in Standard Methods, the rule notes that online distribution of such methods has forced EPA to adopt a new numbering system to track approved test versions rather than simply referencing the publication.