Dames & Moore, 1999 - USDA Forest Service

it was screened against soil criteria Furthermore. because of the more intricate nasal passageways of most
wildlife, it is unlikely that they will be more sensitive to air-borne dust than humans. Since there was no
risk to humans, it is unlikely there would be risk to wildlife.
In Situ Bioassavs
The Forestry Sciences Laboratory of the USFS and the College of Forest Resources at the UW have
conducted a number of revegetation experiments on tailings piles a! the Site. In 1973 and 1974, attempts to
revegetate tailings piles were influenced by higher than normal temperatures and high winds. This
combination of conditions led to desiccation and burial of seedlings. Nevertheless, a variety of grasses
germinated and grew. Tailings piles were treated with dolomite or milorganite (limestone) to increase
tailings pH, ammonium nitrate as a source of nitrogen, and treble superphosphate as a source of phosphorus
(UDFS, 1973). In order of performance, the plants tall wheatgrass (Agropyron elongarurn), crested
wheatgrass (Agrow crestann), alta tall fescue (Fesruca dimcea), and Regar brome (Bromus
biberstenii) established well on the treated tailings piles under inigated conditions. The native plants,
Calamagrostis crmadiensis (a plant in the same tribe as Indian ricegrass), Juncur lbescens and Juncus d
rummondy (both sedges), and Mix lariolepis (a willow), were found in a spring near plot 9 of this study.
Mosquito larvae and tadpoles were also found in a nearby spring.
In 1993, the USFS planted seven different tree seedlings, eight grass species, three shrubs and one forb in
combination with different soil amendments. Fertilizing and mulching gave better results than Milorganite
or no treatment. Ponderosa pine and lodge pole pine were the best performers on soil islands, and Sitka
alder also grew well, despite predation by deer. Over-liming was also thought to be a problem for Sitka
alder. The addition of gravel to the tailings piles reduced the wind drift effect found earlier to cause
decreased productivity, and provide cracks for seedling germination. Four species of forbs and shrubs were
successfully introduced into sewage-Med soils. Growth in lupine was greatest, largely because these
plants contain chemicals which are obnoxious to herbivores and the deer graze on penstemon (Pewemon
speciosus) and alder early in the season.
Despite this success, the USFS noted that natural immigration and establishment of native plants on
unamended soils was proceeding at a faster rate than that on amended soils. Natural immigrants of Douglas
fir, Ponderosa pine and Sitka alder, as well as numerous individuals of spruce were observed within and
outside the transects. At least thirteen species of forbs were also observed to have been successfully been
naturally transported to the tailings piles. Along the creekside, 90 percent of the introduced cottonwood
(Populus trachocarpa) and 35 percent of the alder (Alnur sinuara) were successfully introduced into
untreated soils.
Zabowski and Everett (1997) concluded that the overburden and tailings contained levels of extractable
copper and zinc that should not cause toxicity problems for plants, but that manganese deticiencies might be
a problem. Concentrations of cadmium, copper, nickel, and zinc were not sufficient to cause adverse effects
on Sitka alder or lupine, and the report stated that the lupine looked particularly healthy.
In addition, Kruckeberg and Wu (1992) reported that seeds of Arenaria douglarii, Bromus mollis, and
Eschscholtzia caespitosa collected from soils containing 1680 ppm copper from the Copperopolis Mine site
were very tolerant of soil copper concentrations. Several other species (Vulpia myrous, Lotus purshianur,
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1769340S419Uuly 27.1999.5: 16 PMDRAFT FINAL RI REPORT