State of Oregon

Department of Environmental Quality       Memorandum

_____________________________________________________________________________________

Date:    October 19, 2005

To:  Audrey O’Brien

 NWR Office    

From:    Bob Schwarz

   The Dalles office

Tim Spencer

NWR office

Subject:  Santosh Landfill, ECSI # 1383; Scope of November 2005 sampling

This memo proposes groundwater, sediment, soil and surface water sampling to be conducted by Hart Crowser. Groundwater sampling is scheduled for the week of November 14, 2005. The other sampling proposed here (surface water, wetland pore water, and sediment sampling) will occur either during that week or shortly after that.

The scope proposed here is based on a review of data obtained to date, which includes surface water, sediment and soil samples collected in February 2005, as well as groundwater samples collected in April and August 2005. We have attempted to balance concerns over project cost with the need for sufficient data to adequately characterize the site.

For reference, monitoring wells and past surface water, sediment and soil sample locations are shown on the Sample Location Map: (http://www.deq.state.or.us/nwr/Santosh_Landfill/index.htm).

1.  Analytes. The following analytes should be included in the November 2005 sampling:

a)  Polynuclear aromatic hydrocarbons (PAHs)

b)  Metals

c)  Weak acid dissociable (WAD) cyanide

d)  Landfill indicator parameters

NOTES:

-  PAHs, metals, and cyanide are included because they have been found at concentrations exceeding risk screening levels.

-  Landfill indicator parameters are included because they are relatively inexpensive and provide a measure of the extent of impact from the landfill. The ones we have included to date are: ammonia, nitrate, nitrite, sulfate, chloride, hardness, total organic carbon (TOC), alkalinity, chemical oxygen demand (COD), total dissolved solids (TDS), and total suspended solids (TSS). All of these should be included in the upcoming round except nitrite.

-  Metals analyses for water samples will include both total and dissolved in some cases, and just dissolved metals in others. See Table 1 at the end of this memo.

-  We have already discontinued monitoring for pesticides, herbicides, PCBs and dioxins because they were either not detected, or not detected at concentrations of concern. In addition, we now propose that we discontinue volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs), other than PAHs, which are included in the SVOC list. Of the non-PAH semivolatiles, only two compounds were found slightly above risk screening levels. Of the VOCs, five compounds were found above human health risk screening levels, though not significantly. None were found above ecological risk screening levels.

2.  Sample locations

a)  Groundwater.

i)  Sample for all analytes listed in item 1 above at the following wells:

(1)  Six monitoring wells (MW-1D, 2D, 3D, 3S, 4D, 6S).

(2)  Three supply wells (two on Glacier property, one at Sharinghousen residence).

ii)  Sample for landfill indicator parameters only at the remaining four monitoring wells (MW-1S, 2S, 4S, 5S).

iii)  NOTES: Sampling at the two supply wells on Glacier Northwest’s property and the Sharinghousen well provides two additional offsite points for plume delineation, and allows us to respond to concerns raised at the August 24, 2005 public meeting that we should include nearby supply wells.

b)  Collect pore water samples in the wetlands. Collect pore water samples at six locations in the wetland areas south and west of the landfill. These include three samples from each of two transects.

i)  South transect: This transect extends from the landfill, around wells 3S and 3D, to the creek near sample SS-02. Collect three samples roughly 70 feet apart. The furthest of these will be in the creek bed.

ii)  West transect. This transect extends northwest from the landfill beginning at a point about halfway between MW-1 and MW-2. Samples should be collected about 100, 200 and 300 feet from the toe of the landfill berm.

iii)  Analytes: Those shown in item 1 above.

iv)  Other notes: Pore water samples should be collected by extending a perforated or slotted pipe beneath the ground surface. At locations where there is no standing water, these samples would be shallow groundwater, which should be just below the surface. At locations where there is standing water, this procedure would minimize the impacts of dilution from the surface water.

c)  Surface water and sediment samples from Scappoose Creek. Collect surface water and sediment samples from four locations in Scappoose Creek. These include the three locations included in the February 2005 sampling event (SW/SS-01, 02, and 03) plus a fourth location further downstream. Water samples will be from the water column (as opposed to pore water). Sediment will be collected from the surface of the stream bed. At the location closest to the landfill (SS-02/SW-02), a second, deeper sediment sample will also be collected, at a depth of 1-2 feet. This addresses a concern raised at the last public meeting that surficial sediment may have recently been carried from upstream and might therefore not represent worst-case sediment contamination. Therefore, sampling in the creek will include four surface water samples and five sediment samples.

3.  Summary of samples. Analytes to be included at the various sample points are shown in Table 1.

Table 1

Summary of sample locations, sample analytes and approximate lab costs