Dames & Moore, 1999 - USDA Forest Service

minimal. The data also justified the use of upstream Railroad Creek stations, RC- I. RC-6. andlor RC- 1 1
to monitor area background surface water quality in Railroad Creek.
Statistically derived background values are provided in Table 5.3-1. Complete analytical and field data
for upstream Railroad Creek stations are summarized in Table 5.3-22. Background values were compared
to WQC and discussed in Section 5.3.1. For metals without WQC, the data were compared to MTCA
Method B cleanup levels as discussed in section 5.3.1. The WQC by individual stations and event are
summarized in Tables 5.3.23 through 5.3.27 for informational purposes only.
The data from upstream Railroad Creek for parameters other than metals and organic compounds were
compared to criteria specified in WAC 173-201A. pH measurements ranged from 5 to 8 SU and were
outside of the criteria (6.5 to 8.5 SU) in several instances. Turbidity measurements in the field were
collected, however readings appeared to be erratic and the accuracy of these measurements questionable,
therefore, turbidity was not evaluated further. Dissolved oxygen and temperature were within the criteria
designated in WAC 173-201A.
Organics
Samples were collected at RC-6 in May and' July 1997 for TPH (gasoline, diesel, and heavier than diesel
range) and PCBs. TPHs and PCBS were not detected. PCB analyses were eliminated from future
sampling events.
A sample was collected at RC-6 for TPH in September 1997. TPH was not detected. TPH analyses were
eliminated from future sampling events.
5.3.3.3 Railroad Creek Stations Adjacent to Tailings Pile
Three water quality sampling stations, RC-4, RC-7, and RC-2, were established adjacent to the tailings piles
during the RI (Figure 5.3-1 and 5.3-2). RC-4 is located at the footbridge upstream of the tailings piles. RC-
7 is located downstream of Copper Creek and adjacent to tailings pile 2, and RC-2 is located at the eastern
end of tailings pile 3. Historical data for RC-2 were discussed in Section 5.3.3.1.
Samples were collected at RC-4, RC-7, and RC-2 during four sampling events in 1997 (April, MayIJune,
July, and SeptemberIOctober) and one sampling event in-May 1998. Samples were also collected weekly at
RC-2 from May 19, 1997, to June 16, 1997, to assess event-related variability. Samples were collected from
the south bank at stations RC-4 and RC-2 to evaluate potential localized differences in metal concentrations
across the width of the channel. Laboratory analytical results and field data are summarized in Table 5.3-28.
The sample data for each event and associated AWQC and CWQC are summarized in Tables 5.3-23
through 5.3-27.
Inorganics
The data collected adjacent to the tailings pile were compared to WQC where available and to area
background concentrations (Table 5.3-1) and MTCA' Method B cleanup levels when WQC were not
available. Metal concentrations were then assessed in a downstream trend.
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17693-005-019Uuly 28.1999;l l:W AMDRAFT FINAL RI REPORT