340
P.J. Lechler
Jumbo samples
-
Fig. 1. Location map of the Carson River Superfund Site in west-central Nevada, USA. Carson River
sample locations 2, 3, 6, 9, and 16 are shown, as is the location of sample LHC-2 in Lahontan
Reservoir. Soil sampling locations from area 1 (Sutro and Six Mile Fan locations) and area 2 (Jumbo
location) are also shown
to a greater or lesser extent several centimeters below the surface. Soil samples
were collected from hand-dug trenches as "channel" samples from discrete
pedologic horizons as described above. Samples were obtained from two
principal areas: (1) two sites on the strongly contaminated alluvial fan at the
mouth of Six Mile Canyon and (2) two sites along Jumbo Grade, a small, historic
gold mining area peripheral to the main Comstock District (Fig. 1).
2.2
Analytical Methods
Gold and silver were determined on aliquots taken from the solutions generated
in step 1 of the sequential extraction series described below. Silver was
determined directly by flame atomic absorption spectrometry using D2 background correction. Gold was determined by graphite furnace atomic absorption
spectrometry after extraction into MIBK and back-washing of iron with 10% (vi
P.J. Lechler
Jumbo samples
-
Fig. 1. Location map of the Carson River Superfund Site in west-central Nevada, USA. Carson River
sample locations 2, 3, 6, 9, and 16 are shown, as is the location of sample LHC-2 in Lahontan
Reservoir. Soil sampling locations from area 1 (Sutro and Six Mile Fan locations) and area 2 (Jumbo
location) are also shown
to a greater or lesser extent several centimeters below the surface. Soil samples
were collected from hand-dug trenches as "channel" samples from discrete
pedologic horizons as described above. Samples were obtained from two
principal areas: (1) two sites on the strongly contaminated alluvial fan at the
mouth of Six Mile Canyon and (2) two sites along Jumbo Grade, a small, historic
gold mining area peripheral to the main Comstock District (Fig. 1).
2.2
Analytical Methods
Gold and silver were determined on aliquots taken from the solutions generated
in step 1 of the sequential extraction series described below. Silver was
determined directly by flame atomic absorption spectrometry using D2 background correction. Gold was determined by graphite furnace atomic absorption
spectrometry after extraction into MIBK and back-washing of iron with 10% (vi