Enclosure 1 - 2020 09 14_USACE-EPA_Non Detect Treatment Policy Modification Final.pdf

MEMO FOR: The Record

DATE: September 14, 2020

SUBJECT: Estimating “non-detects” in elutriate and tissue chemistry data submitted in support of Historic Area Remediation Site (HARS) suitability evaluations

Mark Reiss, Chief Dredging, Sediments and Oceans Section Clean Water Division EPA Region 2

Oksana Yaremko, Chief Dredged Material Management Section New York District Army Corps of Engineers

Since March 14, 1997, EPA Region 2 and the U.S. Army Corps of Engineers, New York District (CENAN) have required that testing laboratories submitting analytical data to support HARS suitability evaluations employ a series of conditional rules for estimating values for concentrations of analytes in elutriate and worm tissues when the concentrations are reported as ‘ND’, or ‘non detect’(CENAN 1997; EPA 1999).

The original intent of these conditional rules was to minimize repeating analyses, tests, or sampling for projects with analytical data that met QA/QC standards laid out in the 1992 Regional Testing Manual (EPA/CENAN 1992) but did not meet the listed target detection limits.

The rules accomplished this by substituting ‘non-detects’ above the targets with transparently conservative values (reference values were estimated at zero and project sediment values were estimated at the reported detection limit) for purposes of statistical comparisons, mixing calculations, and comparison to HARS-specific tissue values.

Due to improved performance by contract laboratories since 1997 and the publication of the 2016 Regional Testing Manual which upwardly revised analytical detection limits for various analyte groups, contract laboratories no longer routinely submit data that does not meet target detection limits.

Enclosure 1

By this memorandum, EPA and CENAN document a revision in the policy required for estimating ‘non detects’ in analytical packages supporting HARS evaluations: Statistical comparison, initial mixing calculations, and all comparisons to HARS-specific values will be made using values estimated for NDs that are calculated as ½ the detection (reporting) limit attained by the laboratory. This policy will be applied to all data sets submitted after the date of this memorandum.

REFERENCES:

CENAN. 1997. Memorandum for Contract Laboratories, Subject Line: New approach to handling “non-detects” in elutriate and tissue data. Signed February 28, 1997.

EPA/CENAN. 1992. Guidance for Performing Tests on Dredged Material Proposed for Ocean Disposal. New York District Corps of Engineers, U.S. Environmental Protection Agency - Region 2.

EPA/CENAN. 1997. Memorandum, Subject line: Ocean Disposal of Dredged Material---- Clarification of Two Procedural Elements of Interagency Coordination Between USEPA Region 2 and the New York District, USACE. Treatment of Non-Detected Chemical Data, and Roles and Responsibilities in Preparation of Ocean Disposal Regulatory Compliance Memoranda.

Unsigned, Dated March 14, 1997.

EPA. 1999. Memorandum for CENAN-OP-SD (Joe Olha), Subject Line: Clarification of 28 February 1997 method for statistical comparisons of concentrations of contaminants in tissues of organisms exposed to reference and test sediment treatments.