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PREMISES FOR DEVELOPING AND APPLYING SEDIMENT QUALITY OBJECTIVES

PREMISES FOR DEVELOPING AND APPLYING SEDIMENT QUALITY OBJECTIVES. Presented and (mostly) agreed upon during the October 27, 2004 meeting of the Advisory Committee. BASIC GOAL OF SQO APPROACH. The primary goal is to determine if beneficial uses at a station are impaired

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PREMISES FOR DEVELOPING AND APPLYING SEDIMENT QUALITY OBJECTIVES

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  1. PREMISES FOR DEVELOPING AND APPLYING SEDIMENT QUALITY OBJECTIVES Presented and (mostly) agreed upon during the October 27, 2004 meeting of the Advisory Committee

  2. BASIC GOAL OF SQO APPROACH • The primary goal is to determine if beneficial uses at a station are impaired • Assessment of larger areas and/or waterbodies is a secondary goal • The method for aggregating site-specific data for larger assessments may depend to some extent on the specific application (e.g., waterbody evaluation for 303d listing, dredging)

  3. UNDERLYING PHILOSOPHY • At least two lines of evidence (or legs of the triad) are necessary to conclude a beneficial use is impaired • One line of evidence alone is too subject to error • Need to demonstrate both exposure and effect

  4. TECHNICAL APPROACH • Develop quantitative scaling of indicator values • Avoid simple binary thresholds because: • Thresholds are uncertain and less responsive to degrees of change or difference • Scaled values are more useful for tracking trends • Scaled values produce more meaningful assessments

  5. APPLICATION GUIDANCE • Challenge is to create a consistent MLOE application • Primary users will often be inexperienced engineers • BPJ not a realistic option Goal is to develop a “cookbook” that: • Addresses specific applications • Relates SQO to existing regulatory frameworks • Clearly states how SQO should NOT be used

  6. BENEFICIAL USE PROTECTION CATEGORIES • Aquatic life (Infaunal) effects • Human health effects • Fish and wildlife effects

  7. INDEPENDENT ASSESSMENT OF BENEFICIAL USES • MLOE will be used within each beneficial use, and independent assessments will be conducted for each • If any one beneficial use fails, the station fails, i.e., assessments are not additive across beneficial uses • However, the aquatic life use will probably take precedence because of state of knowledge and availability of data

  8. GENERAL CONCERNS RELATED TO IMPLEMENTATION • Need strategies and guidance for working with imperfect information, e.g., “burden shifting” • Aggregating station-by-station assessments within context of specific regulatory frameworks • Constraints on use of SQO, i.e., what they are NOT suited for

  9. SPECIFIC IMPLEMENTATION ISSUES • Station assessment • Chemistry that is not bioavailable • Imperfect information • Burden shifting mechanism • Incorporating other information • 303d listing guidance • # stations needed for system assessment • Toxic response but low chemistry and OK benthos • Data collection after listing

  10. STATION: UNAVAILABLE CHEMICALS • Hard to define and demonstrate potential for impact • Would depend on plausible mechanism(s) • Possible long list of mechanisms • Station might never get clean bill of health • Margin of safety not clear if have elevated chemistry but OK toxicity and benthos • Establish burden shifting incentives that foster further investigation

  11. STATION: IMPERFECT INFORMATION • Potential problems with data quality, recency, seasonality, conflicting requirements • Need minimum data requirements • Minimum list of chemicals to be measured • Use data less than 5 years old • BRI developed for summer; being assessed for other seasons • BRI requires surficial sediments; dredging requires deeper cores • Guidance must address all these issues

  12. STATION: BURDEN SHIFTING MECHANISM • Value of incentives vs. rigid requirements • Acknowledgment of imperfect information, varied application scenarios • SQOs and related guidance should define several specific burden shifting mechanisms • What are thresholds for triggering burden shifting? • What is the time frame within which incentives play out?

  13. INCORPORATING OTHER INFORMATION • Triad data may not always be definitive • Other data may be valuable in interpreting Triad results • Need to avoid potential for “dueling data” • Three Triad legs should trump other data for final decision making

  14. 303d LISTING APPLICATION • 303d guidance unclear about spatial distribution of samples needed for assessment • SQO guidance should somehow address this • Guidance should include incentives for further investigation when results equivocal • Questions re link between finding of impairment and identification of specific chemical cause • 303d and TMDL processes focus on specific causes • Link between SQO and 303d / TMDL desirable • Examine 303d / TMDL guidance for potential linkages

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