Dames & Moore, 1999 - USDA Forest Service

PCOCs in soil and tailings are further addressed in the human health and ecological risk assessments in
Section 7.0.
5.3 SURFACE WATER
Surface water sample results evaluated in the RI include historical sample data collected by the USGS,
USFS, and Ecology as well as data collected by Dames & Moore during three RI phases conducted in
1997 and 1998. Surface water quality upstream of Holden Mine influences within Railroad Creek was
evaluated using historical data collected by others and through a statistical sampling program completed
during the RI. Samples were collected upstream of the Holden Mine in Railroad Creek, from tributaries to
Railroad Creek including Holden Creek, Big Creek, Copper Creek, and TenMile Creek, and from reference
streams, Bridge Creek, South Fork Agnes Creek, and Company Creek, in the Stehekin watershed to assess
area background surface water quality; the Holden Creek samples were collected in order to evaluate
potential effects of historic prospects reportedly completed by the Howe Sound Company during the period
of operation of the Holden Mine.
The surface water samples were collected for Site assessment historically and during the RI from reaches
of Railroad Creek adjacent to the Holden ~ine and from reaches downstream of potential mine
influences. Tributaries and other areas of inflow to Railroad Creek near the mine and mine area including
copper Creek, Copper Creek diversion, and the portal drainage were sampled historically and during the
RI as part of the Site assessment. Samples from Railroad Creek, Copper Creek, Copper Creek diversion,
Holden Creek, and the portal drainage were also collected during several sampling events to evaluate
water chemistry in relation to seasonal and event-related variations. Sample locations are shown on
Figures 5.3-1, through 5.3-4. Sampling locations .for the RI were located to maintain continuity with
historical sampling efforts where possible.
The samples collected during the RI were analyzed for total recoverable and dissolved metals and
conventional parameters including all or a subset of the following: aluminum, arsenic, barium, beryllium,
cadmium, calcium, chromium, copper, iron, lead, magnesium, manganese, mercury, molybdenum, nickel,
potassium, selenium, silver, sodium, thallium, uranium, zinc, ortholtotal phosphorous, totallamenable
cyanide, total dissolved solids, total suspended solids, chloride, nitratelnitrite, sulfate, alkalinity, color, and
hardness as outlined in the Sampling and Analysis Plan (SAP) and the Quality Assurance Project Plan
(QAPP) associated with each RI phase. Three Railroad Creek stations were also analyzed for
polychlorinated biphenyls (PCBs) and total petroleum hydrocarbons (gasoline, diesel, and heavier than
diesel range). Metal and organic analyses were performed by Analytical Resources, Incorporated (AN),
low-level mercury analysis was performed by Brooks Rand, Ltd., and low-level lead analysis was
performed by Frontier GeoSciences. All three laboratories are located in Seattle, Washington. Field
measurements for pH, specific conductivity, temperature, oxidatiodreduction potential, turbidity, and
dissolved oxygen were collected for each sample as outlined in the SAP and QAPP.
A copy of laboratory reports and associated data validation and related memoranda are included in
Appendix L.
The data were reviewed and validated as outlined in the QAPP. Generally, the data were acceptable and
met the project objectives. Qualifiers of data were assigned in some cases resulting in estimation of the
data. Assigned qualifiers are shown with the summarized data. During the April, MaylJune, and July 1,997
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11693-005-019Uuly 28. 1999;11:09 A M;Dm FINAL RI REPORT