Dames & Moore, 1999 - USDA Forest Service

adjacent to the Site were not necessarily representative of the channel chemistry. The pH and specific
conductivity measurements collected historically indicate that the creek water is generally neutral (5 to 8
SU) and conductivity is low regardless of stream flow or season. In general, copper and zinc were not
detected at RC-1. Copper and zinc were detected at RC-2 and RC-3. Concentrations were generally lower
at RC-3 a,s compared to RC-2. Available stream flow data indicated that copper and zinc are affected by
seasonal flow variations. Iron was detected at all stations. The highest concentrations were detected at RC-
2. The data are inconsistent when comparing analytical data to streamflow variations. The inconsistencies
may be related to the total recoverable analyses versus dissolved analyses.
Patmont (1989) presented the results of sampling and analysis of surface water from Railroad Creek near
Lucerne, at the mouth of Railroad Creek. Mean concentrations of arsenic, iron, and zinc were noted to be
0.46, 976, and 70.2 pg., respectively. The mean concentration for each of the metals is the result of
averaging data collected monthly fiom December 1986 to November 1987. The mean concentrations do not
account for the significant seasonal flow differences.
The historical data for Railroad Creek collected by the USGS and Ecology in Railroad Creek from stations
upstream of the Holden Mine were used for background surface water quality assessment as discussed in
Section 5.3.1. The data collected from reaches in Railroad.Creek adjacent to and downsh-eam of the mine
influenced area generally were not compiled with the RI data for PCOC evaluation due to the limitations
noted above.
5.3.3.2 Upstream Railroad Creek Stations (RC-1, RC-6, and RC-11)
Stations RC- 1, RC-6, and RC- 1 1 were considered to be upstream of mine influences (Figure 5.3- 1). Station
RC-1 was historically considered as background, i.e., unaffected by mining activities. Historical data for
RC- 1 area available from two studies conducted between 1982 and 1983 (USFS, 1983) and between 1989 to
1995 (PNL); however, the possible use of tailings andlor waste rock as fill along the banks and at the
ballfield near RC- 1 during mine operations was discovered and resulted in the establishment during the RI
of station RC-6 several hundred yards upstream near the Glacier Peak Wilderness boundary. RC-I 1 was
located upstream of RC-6, above the confluence of Holden Creek and within the Glacier Peak Wilderness
boundary.
During the RI, samples were collected at RC-6 and RC-1 during four sampling events (April, MayIJune,
July, and, September) in 1997 and one sampling event in May 1998. RC-1 was sampled across the width of
Railroad Creek as well as near the north and south banks during May 1997 and September 1997 to
determine if localized differences of metal concentrations exist across the channel. Station RC-6 was
sampled weekly from May 19, 1997, to June 16, 1997, to assess event-related variability. Station RC-11
was sampled during two sampling events, October 1997 and May 1998.
Inorganics
As previously discussed in Section 5.3.1, the data collected from stations in Railroad Creek upstream of
the mine influence were included in the background surface water quality assessment including samples
collected across the width of the creek and samples collected on the banks. At the upstream stations,
metal concentrations did not indicate variability based on sample location in the span of the creek. The
background surface water quality assessment showed that seasonal variability of metal concentrations was
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