Dames & Moore, 1999 - USDA Forest Service

Seep data were compared to MTCA groundwater levels and water quality criteria provided in WAC 173-
200. The PCOCs identified for seeps and monitoring wells associated with tailings pile 2 are summarized
below. I
PZ-1A
PZ- 1 B
PZJA
TR-4A
TP2-5A ,
TP2-8A
TPZ-I 1A
SP-3
SP-4
Tailings Pile 3
Spring
Fe, pH
Fe, Mn, TDS, SO4
As, color, Fe, TDS, SO4
Fe, TDS, SO4
S04, pH
Mn, TDS, SO4, pH
pH
As, Be, Cd, Cu, Fe. Mn, TDS,
sod, PH
Cd, Fe, Mn, TDS, SO4, pH
Summer
Not Sampled
Not Sampled
Not Sampled
, NotSampled
Not Sampled
Not Sampled
Not Sampled
Cd, Fe, Mn. TDS, Sod, pH
Cd, Fe, Mn, TDS, SO4, pH
Fall
Not Sampled
Fe. Mn, .TDS. SO4, pH
As, Fe, TDS, SO4
Fe, TDS, SO4
Not Sampled
Mn, TDS. SO4, pH
ms, so,, pH
Fe, Mn, TDS, SO4, pH
Not Sampled
Groundwater samples were collected from monitoring wells (PZ~A, TP3-4, TP3-6A, TP3-8, TP3-9, and
TP3-IOA), lysimeters (TP3-4L, TP3-6L, TP3-LOL), and seeps SP-5, SP-17, and SP-18. Samples were
also collected from monitoring wells DS-I and DS-2 and seep SP-21 east of tailings pile 3. Sample
locations are shown on Figure 5.4-1 and analytical data are summarized on Tables 5.4-1 and 5.4-2.
Sample data from monitoring wells screened underneath tailings pile 3 were collected in the spring and
fall of 1997 with the exception of TP3-4 which was sampled only in the spring. Data were compared to
..- MTCA Method A and B cleanup levels. Metals were below MTCA with the exception of lead'at TP3-4
in the spring and manganese at PZ-6A and TP3-9 in the spring and fall, and at TP3-8 and TP3- 1 OA in the
fall. Cadmium at TP3-4 was 14 pg/L compared to the MTCA Method A cleanup level of 5 pg/L.
Manganese concentrations ranged from 1,370 to 3,490 pg/L,.above the MTCA Method B cleanup level of
747 pg/L. Lead and manganese are identified as.PCOCs in the wells noted. Iron concentration in wells
on tailings pile 3 ranged from