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Project: Advisory Panel for CECs in Freshwater, Coastal, and Marine Ecosystems

Background and Objectives

Environmental managers are challenged with addressing contaminants of emerging concern (CECs) in the face of limited knowledge about their sources, pervasiveness, and effects. In 2009, the State of California convened a panel of experts to provide recommendations on how current knowledge of CECs should influence their regulatory activities; however, this effort was limited in context and scope to the State’s Recycled Water Policy. Many of the questions to be addressed by the recycled water panel were also relevant to ambient aquatic environments. To leverage that effort, the David and Lucile Packard Foundation partnered with SCCWRP to support a second panel that provided the State with recommendations on how to best limit the impact of CECs on oceans, estuaries, and coastal wetlands. The State Water Board also expanded the panel’s charge to also provide guidance on appropriate monitoring and management strategies for CECs in California’s freshwater ecosystems.

This panel was asked to address the following questions:

1. What are the relative CEC contributions of wastewater and stormwater discharges released into inland freshwater and coastal aquatic systems*?

2. What specific CECs, if any, are most appropriate for monitoring in discharges to inland freshwater and coastal aquatic systems and what are the applicable monitoring methods and detection limits?

3. How are these priority constituents affected by the chemistry, biology, and physics of wastewater treatment processes, discharge into and transport by streams, rivers and estuaries, and mixing and dilution with receiving inland, coastal, and ocean waters?

4. What approaches should be used to assess the biological effects of CECs on sentinel species in inland freshwater and coastal aquatic systems?

5. What is the appropriate design (e.g. media, frequency, locations) for a CEC monitoring and biological effects assessment program given current monitoring methods, and what level of effects will be detectable with such a monitoring program? How does the sensitivity of the monitoring and assessment program vary with investment?

6. What concentrations of CECs or levels of biological effects should trigger further actions and what options should be considered for further actions?

* Inland freshwater systems refer to surface waters including streams, rivers, lakes and reservoirs. Coastal aquatic systems are the territorial marine waters of the State as defined by California law, i.e., those extending up to three miles offshore. This question also refers to releases outside three miles that impact state waters or any ground and surface waters (fresh, brackish, or saline) within state boundaries that are hydrologically connected to the coastal ocean.


This project was initiated in 2009 and completed in 2012.


Seven panel members were chosen for their expertise in the following fields: biochemistry, analytical chemistry, civil engineering, coastal/marine resources, epidemiology/risk assessment, ecotoxicology, and human health toxicology. This panel reviewed the scientific literature regarding CECs in aquatic systems, and held several meetings to discuss how to answer the key questions. The knowledge gleaned through this effort was synthesized into written recommendations for the management community.


Event Related Materials
October 30
Panel Convened  
January 12, 13, 15 Panel Meeting #1
September 30 - October 1
Panel Meeting #2


Panel Charge and Conceptual Approach - Dan Schlenk
Special Studies - Keith Maruya
Diagnostic Tools - Jerry Diamond
WERF Report Out - Scott Dyer
Panel Report Out - Dan Schlenk

Session 1: Welcome, Panel Charge, and Special Studies
Session 2: Diagnostic Tools and Public Comment
Report Out and Public Comment


January 31 - February 1
Panel Meeting #3
(at Hollings Marine Laboratory in Charleston, SC)

Panel Report Out
October 12-13
Panel Meeting #4

Panel Report Out
January 9-10
Panel Meeting #5

Panel Report Out
February 22
Draft Report for Stakeholder Review Draft Report
March 19
Public Comments Due to SCCWRP  
March 23
Panel Meeting #6

Panel Response to Comments
April 27
Final Report
Monitoring Strategies for Chemicals of Emerging Concern (CECs) in California’s Aquatic Ecosystems: Recommendations of a Science Advisory Panel

Jon Bishop of the State Water Resources Control Board presents the panel’s charge during their January 2010 meeting.


Given the thousands of chemicals potentially present in the aquatic environment and rapidly evolving information about CECs, the Panel created a transparent approach to focus the universe of CECs based on their potential for health effects and their occurrence in waters receiving discharge of municipal wastewater treatment plant effluent (“WWTP effluent”) and stormwater. The health and environmental risk for individual CECs within this select group was then assessed to guide prioritization of chemicals for inclusion in current and future monitoring programs. The Panel adopted a risk-based screening framework with four primary steps:

  1. Develop monitoring trigger levels (MTLs) for CECs that pose the greatest potential risk to aquatic systems based on published effects concentrations.
  2. Compile measured or predicted environmental concentrations (MECs or PECs) for CECs for which MTLs could be estimated.
  3. Identify those CECs that have the greatest potential to pose a risk by comparing MECs (or PECs) to MTLs.
  4. Apply the risk-based screening framework (steps 1-3) to each of three representative scenarios that capture the key types of exposure (sources and fate) to CECs in the State’s inland, coastal and marine receiving water systems:
• Scenario 1: a WWTP effluent-dominated inland (freshwater) waterway;
• Scenario 2: a coastal embayment that receives both WWTP effluent and stormwater discharge; and
• Scenario 3: offshore ocean discharge of WWTP effluent.

The Panel laid out an adaptive, four‐phase approach for implementing CEC monitoring programs for WWTP effluent and stormwater discharges to receiving waters of the State, within the various existing statewide, regional and local monitoring programs. In addition, they recommended that the State promote and support research initiatives in three broad categories to improve the scope and performance of monitoring and data interpretation for waters receiving WWTP effluent and stormwater discharge: development of bioanalytical screening tools; filling data gaps on CEC sources, fate, occurrence and toxicity; and assessing the relative risk of CECs and other monitored chemicals.


This project was conducted in collaboration with the Packard Foundation, the State Water Resources Control Board, and panel members (below), with stakeholder input from a variety of public and private entities.

Panel Members:

Stakeholder Advisors:

  • Chris Crompton (California Stormwater Quality Association)
  • Jim Colston (Tri-TAC)
  • Mark Gold (Heal the Bay)
  • Amber Mace (Ocean Protection Council)
  • Rick Moss (State Water Resources Control Board)
  • Linda Sheehan (California Coastkeeper Alliance)
For more information on Ecosystems Advisory Panel, contact Keith Maruya at (714) 755-3214.
This page was last updated on: 7/1/2014