Dames & Moore, 1999 - USDA Forest Service

The data for seeps associated with the east waste rock pile were compared to groundwater quality criteria.
The following PCOCs were identified.
SP-8
SP-19
SP-IOW
SP-I OE
5.4.2.5 Maintenance Yard
Spring
Cd, Ck Zn, pH
Cd, Cu, Zn, pH
Cd, CU pH
Cd Cu, Fe, pH
Summer
Not Sampled
Not Sampled
Cb Cu, pH
Not Sampled
Fall
Not Sampled
Not Sampled
Not Sampled
Not Sampled
Samples were collected from seeps (SP-7, SP-22, SP-24, and SP-25) and a groundwater monitoring well
(HBKG-1) associated directly or indirectly to the maintenance yard. Seep samples were collected in May
1997 at each seep and well. Additional samples were collected at SP-7 in July and September and at
HBKG-1 in September. Sample locations are shown on Figure 5.4-1. Analytical data are summarized in
Tables 5.4- 1 and 5.4-2.
Aluminum, cadmium, copper, iron, manganese, and zinc concentrations ranged From 20 to 1,790 pg/L, 26
to 48 p a, 1,930 to 7,560 pg/L, 120 to 710 pg/L, 116 to 451 pgk, and 3,470 to 6,430 pg/L, respectively.
The lowest concentrations were detected in July, followed by May then September with the exception of
manganese which was lowest in May, followed by July then September. Field pH measurements ranged
from 4.7 to 6.9 SU. The lowest pH (4.7 SU) was measured in September, followed by May (5.6 SU) and
July (6.9 SU).
One sample was collected in May 1997. Additional samples were not collected as the seep was not
flowing in July or September. Concentrations of aluminum, cadmium, copper, iron, manganese, and zinc
at SP-22 were 190 pg/L, 47.5 pg/L, 2,140 p a,