WDNR review of PCP degradation study

• What was the goal of the investigation summarized in this letter?

  As noted in our description of the PCP degradation study report, the purpose of the technical memorandum was to provide lines of evidence that pentachlorophenol (PCP) can be biodegraded in the natural environment—and to illustrate that biodegradation is the primary mechanism for breakdown of PCP in groundwater at the Wauleco site.

• What key information should readers take away from this letter?

  The WDNR letter was in response to the PCP degradation study report. Based on their review of the technical memorandum, the WDNR agrees that PCP can be degraded naturally, and that PCP concentrations in groundwater across much of site have decreased over time.

• Why is this communication relevant?

  It shows that Wauleco and the WDNR have reached a general agreement about an important point—that PCP can naturally degrade at the site and that there’s evidence it’s doing so. While the WDNR agrees with the findings and conclusions of the technical memorandum, they’ve requested additional field studies to support the conclusion that biodegradation is the primary natural attenuation mechanism for the central portion of the groundwater plume at the site. This led to Wauleco proposing a site-specific bio-trap study.