EQC Talking Points for Arsenic Rulemaking

April 21, 2011 Meeting

1. Introduction

2. Here today to recommend that the Commission adopt revisions to Oregon’s water quality standards for arsenic, including revisions to the human health numeric criteria and the adoption of an arsenic reduction policy.

3. First I’d like to refresh your memory on some background information and then I will provide an overview of the specific changes as well as the reasons DEQ concludes they are the best policy choice at this time and are scientifically defensible.

4. Background:

•  2008 directive to look at the science behind naturally occurring earth metals in response to testimony the criteria are well below common natural levels in Oregon and that the arsenic criteria under the Clean Water Act are much lower than drinking water standards established under the Safe Drinking Water Act, known as maximum contaminant levels.

•  2008 directive to provide for cost effective and environmentally meaningful implementation of the human health criteria.

•  DEQ conducted a review of three naturally-occurring earth metals in response to these directives: iron, manganese and arsenic.

•  In response to requests by regulated parties, DEQ separated the rulemaking process for the three metals from the larger toxics package in order to revise the criteria on an accelerated time frame. The changes will affect permits that are due for renewal and the next water quality assessment (303d list).

•  The EQC adopted the iron and manganese revisions in December, 2010, but DEQ needed additional time to consider and respond to comment on the arsenic criteria, which has not been completed.

5. Policy objective for these criteria is to protect human health, as required by the federal Clean Water Act, and account for the presence of arsenic in Oregon waters from natural sources.

6. Recommended revisions to the numeric arsenic criteria:

•  The revisions are based on EPA’s criteria calculation methods and equations, but use values for some of the calculation variables that DEQ concludes are more appropriate for Oregon than the national default criteria.

•  DEQ is recommending different criteria for FW and SW due to different bioconcentration rates among fresh and salt water biota and arsenic speciation in the marine environment.

•  DEQ also considered information on estimated natural background levels.

7. FW details

8. SW details

9. arsenic reduction policy