Dames & Moore, 1999 - USDA Forest Service

Station'
RC-4
RC-7
RC-2
RC-5
RC-10
RC-8
RC-3
April 1997
>AWOC/>CWOC
Cu, Z d Cu, Zn
(Fe) ZnICd, Zn
(Fe) ZdCd, Zn
(Fe) ZdCd, Zn
Not Sampled
None
NoneJZn*
MayIJune 1997
>AWOC/>CWOC
Cd, Cu, ZdCd. Cu, Pb, Zn
Cd, Cu, ZdCd, Cu, Pb, Zn
Cd, Cu, ZdCd, Cu, Zn
Cd, Cu, ZnICd Cu, Zn
Not Sampled
Not Sampled
Cu, Zn*/Cy Zn*
July 1997
>AWOC/2CWOC
Cu. Zn*/Cu. Pb, Zn*
Cu, Zn*/Cu. Pb, Zn*
Cy Zn*lCu, Zn*
Cu, Zn*/Cu, Zn*
Not Sampled
Not Sampled
None
' South bank samples not included
(Fe)- lron is listed as criteria without reference to chronic or acute status.
SeptemberIOctober
1997
>AWOC/>CWOC
NondPb
(Fe) NondPb
(Fe) ZdZn
(Fe) ZdZn
None
CdICd, Pb
None
May 1998
>AWOCI>CWOC
Cd, Cu. ZdCd. Cu. Zn
Cd. Cu. ZdCd, Cu. Zn
Cd, Cu, ZdCd. Cu. Zn
Cd. Cu, ZnICd. Cu. Zn
Cu ZdCd, Cu. Zn
Not Sampled
Cu. ZdCu. Zn
Where zinc is marked with an asterisk (Zn*) in the above table, the exceedance of WQC could have been
affected by the introduction of zinc during the field filtration process. Therefore, zinc concentrations at RC-
3 and zinc concentrations detected in July 1997 should only be considered "apparent" exceedances.
Samples collected from the south banks at RC-4 and RC-2 in 1997 were compared to samples collected
across the width of the creek. Concentrations of aluminum, cadmium, copper, manganese, and zinc detected
on the south bank of RC-4 during May 1997 were above concentrations detected across the creek width.
Concentrations of the other metals in July and September were similar between the bank and creek width
samples, with the exception of copper. Data collected from the south bank at RC-2 were similar to data
collected from the width of the creek.
The south bank results from RC-4 and RC-2 were compared to state and federal WQC. Metals above WQC
in May, June, and July were generally comparable to the metals above WQC in samples collected across the
creek width. The September 1997 data compared to state WQC indicate that copper and zinc at RC-4 and
zinc at RC-2 are above WQC. The data from RC-4 indicate that copper is also above federal WQC during
this'timeframe.
In general, concentrations in the upstream stations did not fluctuate with seasonal or stream flow variations.
lron and,hardness were inversely proportional to stream flow. Metal concentrations at the adjacent and
downstream stations were generally higher that the upstream locations. The widest variation occurred in
May. Concentrations were often similar by September. Most metal concentrations increased downstream
of RC-1 at RC-4. Concentrations fiom RC-4 to RC-2 were similar or slightly decreased with the exception
of iron; which increased substantially at RC-7. The concentrations of metals decreased from RC-2 down to
RC-3.
8.3.3.2 Portal Drainage
The portal d;ainage .reflects overland flow groundwater discharge fiom the underground mine. Water
samples were collected during MayIJune, July, and Septemberfoctober 1997, and May 1998 events. The
data collected from the portal drainage and the analytical indicate seasonality in exceedances of applicable
regulatory thresholds, as tabulated below.
Data collected at P-1 (portal) and P-5 (portal drainage confluence with Railroad .Creek) were compared to
WQC for surface water (WAC 173-201A) and MTCA Method B cleanup levels for surface' water.
\\DM~SEAI\VOLI\COMMOMWP\WDATA\OOSU~EPORTSWOLDEN-~W\~-O.~OE 8-29 DAMES & MOORE
17693-005-019Uuly 28,1999;10:24 AM;DM FINAL RI REPORT