NEXT MEETING: GARDEN GROVE, CALIFORNIA - AUGUST 5-9 2024

A December 2020 publication by the University of Washington reported that p-phenylenediamine (PPD), an antiozonant added to tires for more than six decades, is being converted by ozone to 2-anilo-5-[(4-methylpentan-2-yl)amino]cyclohexa-2,5-diene-1,4-dione (6PPD-Q), a quinone that has been found in stormwaters and Pacific NW rivers after rainfall events at concentrations toxic to Coho salmon. Early in 2021, Region 10 EPA convened a monthly roundtable of federal, state and tribal scientists to share information on this contaminant. The group expressed a strong need for an EPA method for this contaminant in surface and storm waters. EPA initiated a collaborative effort with Eurofins-Sacramento to conduct a single-laboratory validation study of an existing Eurofins LC-MS/MS method that utilized SPE and isotope dilution quantitation. Region 10 worked with the EPA Office of Water to develop a Quality Assurance Project Plan for the single-laboratory validation study with sufficient rigor to support development of a formal EPA 1600-Series method. 

On January 30, 2024, in what the Region 10 Administrator termed  lightspeed,  EPA delivered Draft Method 1634, an LC-MS/MS procedure that includes data from the single-laboratory study that demonstrate that 6PPD-Q can be reliably measured in surface water and stormwater at approximately 2 ng/L, well below the 95 ng/L LC50 for Coho. Testing of wastewater samples is underway and other matrices are under consideration. Publication of the draft method will promote a more consistent approach to future analysis of 6PPD-Q and provide tribes and local governments with an important tool for better understanding stormwater and surface water quality. This project also demonstrates EPA s commitment to respond to emerging contaminant needs in relatively short order. EPA s Office of Water will assess whether to pursue a multi-laboratory study in the future.