Dames & Moore, 1999 - USDA Forest Service

5.4.2.8 Lucerne Well
The well at the Lucerne USFS guard station was sampled in both May and September 1997. The data
collected were compared to MTCA cleanup levels and federal MCLs. Metal concentrations detected
were not above MTCA cleanup levels. Iron (3 10 p@) detected in the sample collected in June 1997 was
just above the secondary federal MCL (300 pg/L). The concentration detected in October 1997 decreased
to 200 pg/L. Iron was identified as a PCOC at Lucerne. Measured pH (5.25 to 5.49 SU) was below
groundwater quality criteria (6.5 to 8.5 SU).
5.4.3 Interstitial Pore Water Data and Mill Building Drip Water
5.4.3.1 Interstitial Pore Water
Samples of interstitial pore water (BKG, TP1-2, TP2-1, TP2-2, TP3-1, TP3-2, and DG) were collected in
April 1994 from locations shown on Figure 5.4-1 (USBM, 1994). Samples were reportedly collected by
pushing a syringe fitted with a Teflon tip into the streambed and withdrawing the water from between the
particles of the streambed. Due to potential problems with sample collection technique and unavailability
of quality assurance information related to sample data, these data are considered usefbl for screening
purposes only. Analytical results are summarized on Table 5.4-5.
Results from sample location BKG, upstream of the tailings piles, indicate neutral pH (7.3) and low metal
concentratioris. Aluminum and copper concentrations were below detection limits and iron and zinc
concentrations were 20 pg/L.
' Generally, metal concentrations increased at TP1-2 relative to BKG data. The highest interstitial iron
concentration (95,000 p a) was present at PI-2. The pH from sample TP1-2 was 3.4 SU.
Sample TP2-1 also containkd low pH and higher iron, aluminum, and copper concentrations than detected
at BKG. pH for sample TP2-1 was 4.0 SU. Aluminum (17;000 pg/L) and copper (250 p/L)
concentrations measured at TP2-1 were higher by at least an order of magnitude than in the additional
samples collected.
Samples downstream of location TP2-1 indicate that pH becomes less acidic and dissolved metal
concentrations decrease from TP2- 1 downstream to TP3-2, with the exception of lead.
Sample DG-1 was collected downstream of the northeast corner of tailings pile 3. Iron (22,000 pa) and
zinc (6,000 pgL) concentrations detected in sample DG-I were higher than concentrations at TP3-2 by
100 times or greater.
5.4.3.2 Mill Building Drip Water
Two samples of water dripping off surfaces within the mill building were collected in 1995 (Kilburn and
Sutley, 1996) and an additional seven samples were collected in 1996 (Kilburn and Sutley, 1997). These
samples contained concentrations of aluminum, cadmium, copper, iron, manganese, and zinc, ranging
from 32 to 76,000 pg/L, 22 to 3000 pg/L, 450 to 650,000 pgL, not detected to >500,000 pg/L, 56 to
33,000 and '3,200 to 350,000 pa, respectively. Dissolved metals results for the samples are
summarized in Table 5.4-6.
\U)M-SEAI\VOLI\COMMOMWP\WDATAUX)~PORTSWOLDM-2UU\5-O.d~ 5-54 DAMES & MOORE
17693-005-019Uuly 28. 1999.1 1 :09 Ah4;DRAFT FINAL R) REPORT
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