Oregon Administrative Rules
Chapter 340 - DEPARTMENT OF ENVIRONMENTAL QUALITY
Division 40 - GROUNDWATER QUALITY PROTECTION
Section 340-040-0108 - Method and Criteria for Establishment of Maximum Measurable Levels of Contaminants in Groundwater: General Policies

(1) Program Priorities: Groundwater quality shall be protected throughout the state of Oregon. However, the Commission shall concentrate its groundwater quality protection implementation efforts in areas where the practices and activities related to the use of one or more substances of concern have the greatest potential for degrading groundwater quality and where potential groundwater quality pollution would have the greatest adverse impact on beneficial uses.

(2) Beneficial Uses: Groundwater shall be protected for both existing and future beneficial uses so that the State may continue to utilize the resource for whatever beneficial uses the natural water quality allows. High quality groundwater shall be maintained for present and future uses.

(3) Scientific Evidence: The Commission shall set a maximum measurable level for a contaminant or substance of concern only when there is sufficient scientific evidence to show that the contaminant or substance of concern may cause adverse effects to public health or the environment.

(4) Naturally Occurring Contaminants: For contaminants that naturally occur in groundwater in concentrations above the maximum measurable level, the Commission shall consider the natural background level to be the equivalent of the maximum measurable level for that groundwater source.

(5) Public Health: The Department shall, for the purposes of establishing maximum measurable levels and developing environmental and health advisories, consult with the Oregon Health Division regarding human health concerns.

(6) Wildlife: A preliminary assessment by EPA indicates that aquatic criteria are not in all cases protective of wildlife (e.g., include mercury, selenium, polychlorinated biphenyls, DDT and possibly chlorinated alkanes, benzene, phenols as well as metals in general). However, for contaminants or substances of concern, the Department may rely on the limited information available in EPA's Water Quality Criteria for protection of aquatic and wildlife species as their foundation for recommendations to the Commission, unless scientifically valid evidence shows this to be inadequate.

(7) The Commission recognizes, however, that studies of aquatic and wildlife species are extremely limited. This reduces confidence in the Commission's ability to ensure that maximum measurable levels of contaminants will be protective of those groups in the environment.

(8) Methods Flow Chart: A flow chart, Appendix 1, graphically describes the methods to be used in establishing maximum measurable levels, which may, as appropriate, be used to interpret these rules.

(9) Public Support via Education: Public support of the groundwater protection program is essential to its long-term success, and voluntary compliance will likely lead to the least cost program. Therefore, the Commission is encouraged to conduct ongoing public education and demonstration programs designed to inform the public concerning:

(10) Other Rules and Statutes Unchanged: Nothing stated in these rules is intended to change or be changed by OAR 340-040-0001 to 340-040-0080 (General Groundwater Protection); OAR 340, division 108 (Spills and Other Incidents); OAR 340, division 150 (Underground Storage Tank Rules); OAR 340, division 122 (Environmental Clean-up Rules); or OAR 690, division 10 (Appropriation and Use of Groundwater).

(11) While economics, detection technology and feasibility are excluded from consideration in establishing an MML, these factors may be considered in determining appropriate remedial responses.

View a PDF of appendices by clicking on "Tables" link below