Department of Ecology Revises Direction on Human Health Water Quality Criteria

Published Feb 10, 2014

This morning, at what is likely to be the penultimate Delegates Table meeting, the Washington Department of Ecology announced its current direction in state human health water quality criteria for three toxic chemicals: arsenic, methyl mercury and polychlorinated biphenyls (PCBs).  These chemicals have emerged as a particular concern as Ecology has been under pressure to adopt Washington criteria on the same basis as the state of Oregon.

The regulated community, including business and local governments, has been very concerned that the Oregon criteria for chemicals such as PCBs, if applied in Washington, would impose crippling compliance obligations under water quality permits. Monitoring data indicate that most of Puget Sound from Olympia to the Strait of Juan de Fuca currently would not meet the very conservative Oregon criteria. This could result in a strict prohibition on any new or expanded discharges from individual businesses or local governments within the Puget Sound basin and other broad reaches of the state.

In today’s announcement Ecology indicated that the derivation of criteria for PCBs will be based on tribal fish consumption rates with an adjustment to average weight consistent with EPA guidance and tribal fish consumption studies. Ecology is also proposing to use the risk/hazard toxicity factor used by the Washington Department of Health in developing fish advisories. This approach is consistent with the Washington risk policy for toxic criteria and the US Environmental Protection Agency’s guidance on acceptable risk exposure and provides broad assurance that waters meeting the proposed criteria will be protective to all consumers of fish from state waters.

Kelly Susewind, Deputy Director of Ecology, reported that Ecology has had several discussions including an all-day meeting with EPA Region 10 to review this approach. Angela Chung, head of water quality standards for Region 10, confirmed that EPA headquarters and Region 10 staff views this approach as positive.  EPA’s only concerns are over the approach proposed for arsenic and how Ecology will factor residual source contribution for non-carcinogens. These concerns do not impact the proposed derivation of criteria for PCBs.

The following table is from Ecology’s presentation to the Delegates Table:

Ecology is planning to issue a draft rule for public comment in March and anticipates one additional Delegates Table meeting to review the rule before it is released for public comment. For more information, contact James Tupper at

  • For more information on the presentation, click here.
  • For more information on the development of HHWQC in Washington, click here.