Proposed NPDES Rule Requires ‘Sufficiently Sensitive’ Test Methods
In a Federal Register notice published June 23, the EPA proposed changes to its permitting program under the Clean Water Act (CWA) to ensure the use of sufficiently sensitive analytical methods for monitoring chemical pollutants in discharge water.
Specifically, the new rule affects the CWA’s National Pollutant Discharge Elimination System (NPDES). Its purpose is to specify that applicants and permittees must use analytical methods that are capable of detecting and measuring pollutants at, or below, current water quality criteria.
This proposal is based on requirements in the CWA and existing EPA regulations and is directed at NPDES analytical methods for all pollutants, including the ‘Analytical Methods for Mercury in NPDES Permits,’ as addressed in the 2007 EPA Methods Update Rule. If no specific analytical method is approved or required under the proposed rule, an NPDES applicant may use any suitable and sufficiently sensitive method. However, the applicant must describe the method and include documentation of that method’s limit of detection.
The amendments in this proposed rule affect only chemical-specific methods; they do not apply to the methods for measuring whole effluent toxicity or their use. The changes could potentially affect state permitting authorities, publicly owned water treatment plants, and industrial plants that need NPDES permits for their discharges.
Once the proposed rule is finalized, states will need to amend their own regulations, if necessary, to ensure that only sufficiently sensitive methods are used to produce data for permit applications and monitoring.
The EPA is accepting comments on this rule until August 9, 2010. More information is available at http://edocket.access.gpo.gov/2010/2010-15254.htm