Changes implemented as part of Permit Modification Request
UMCDF-06-010-CMP(3) entitled CMP SAP Changes
Approved February 2008

Permit modification request (PMR) UMCDF-06-010-CMP(3) proposed changes to the Comprehensive Monitoring Program (CMP) Sampling and Analysis Plan (SAP).  The CMP SAP is Attachment 5 of the Hazardous Waste Permit under which the Umatilla Chemical Agent Disposal Facility (UMCDF) operates.  The designation of a Class 3 PMR means it received the highest level of public involvement.  It was subject to two public comment periods during the process.  The following changes were approved by the Oregon Department of Environmental Quality (DEQ) on February 4, 2008.

The DEQ approved elimination of terrestrial invertebrate sampling.  Prior to this change, terrestrial invertebrates were collected three out of four scheduled events (January events were excluded).

Collection of surface water was also eliminated.  Results of water sampling showed few detected results (three percent detects for organics, four percent for inorganics) and statistical trending was not possible.  Sources for water samples were flowing waters of the Umatilla River, water from the Columbia River used as a wetland water source, and one spring-fed pond.

Sampling frequency was changed to semiannually at four of six sites in Zone 3 near Pendleton, Oregon.  Sites 3‑1, 3‑3, 3‑4, and 3‑6 will be sampled in April and October, and Sites 3‑2 and 3‑5 will be sampled every quarter.  Site 3‑7 in Washington will also keep the quarterly sampling schedule.

The number of agent analyses in soil was reduced.  Sites 1‑3, 1‑4 and 1‑10 will continue to be analyzed for chemical agent.

Several changes were approved that affect baseline threshold data.  Baseline threshold values will be recalculated using an upper tolerance limit (UTL) rather than the upper confidence level (UCL).  This brings the process in line with EPA guidance documents, and is more appropriate for the intent of CMP comparisons.  Two years of surrogate testing will be included in the baseline threshold recalculations.  In addition, reporting limits will now be added to the screening process when operational data are compared to baseline.

A different strategy has been approved for presenting trending information.  Recurring values above baseline (5 or more) will be listed in a table in each quarterly report, but only those with significant upward trends will be graphed in the quarterly report.  Annual reports will show all recurring values (5 or more) in a graph, regardless of significant upward trend estimates.

DEQ approved biannual sampling at the long-term soil sampling stations.  The first biannual event will be in October 2009.

Changes will be implemented prior to the April 2008 sampling event.  Historical data will still be maintained for those media where collection has ended.  An updated Baseline Threshold Report will be posted to this website when it is completed.