‘New paradigm’ need for CECs, US workshop finds

The need for a new paradigm for water and wastewater treatment, which prioritizes chemicals (or chemical classes) with similar modes/mechanisms of action for further evaluation, was a principal conclusion of a workshop held in California, USA, in April 2009, the results of which have just been published.

The workshop, titled Managing Contaminants of Emerging Concern (CECs) in California: A Workshop to Develop Processes for Prioritizing, Monitoring and Determining Thresholds of Concern was held on 28-29 April 2009 in Costa Mesa. The following agencies sponsored the workshop:

  • California Ocean Protection Council
  • California Ocean Science Trust
  • National Water Research Institute
  • San Francisco Estuary Institute
  • Southern California Coastal Water Research Project
  • University of California, Irvine – Urban Water Research Center.
  • Workshop participants began by agreeing that the current chemical-specific risk assessment approach is neither feasible nor cost-effective for prioritizing and managing the vast majority of CECs. The participants noted that chemical-specific risk assessment approaches will continue to play a role in the regulation of contaminants for those chemicals with known adverse effects.

    There are 129 priority chemicals currently regulated by the US Environmental Protection Agency under the Safe Drinking Water Act and Clean Water Act, but tens of thousands of CECs exist that may potentially require assessment to ensure their impacts to human and ecological health are minimal.

    Monitoring of CECs would be a key part of the proposed new paradigm, but workshop participants stressed that “we are currently in the investigative phase, and developing regulatory limits would be premature at this time”. Identifying a clear set of goals for investigative monitoring (eg, to address unanswered questions on CEC occurrence and concentrations, or to assess the removal efficiency of existing or new treatment processes) was deemed essential for filling the most critical data gaps and obtaining maximum benefit from the limited resources available to support such studies.

    The participants overwhelmingly agreed that creation of a single master list of CECs that agencies could apply effectively across all applications was unlikely. Instead, participants concluded that the logical next step in this process will be to formulate preliminary lists of priority CECs, indicator compounds, and surrogate parameters that would address the investigative monitoring goals for the various applications, including drinking water, recycled water (nonpotable and potable reuse), wastewater discharges, and ambient receiving waters.

    These preliminary lists could then be incorporated into existing and/or planned collaborative studies that are organized at the watershed or regional scale. Results from these pilot studies would be used to fill key data gaps and initiate the iterative process formulated during the workshop for prioritizing those CECs in need of regulatory review.

    The full report can be downloaded from the National Water Research Institute website.