8    REMEDIATION OF METALS-CONTAMINATED SITE NEAR A
SMELTER USING SLUDGE/FLY ASH AMENDMENTS
John A. Oyler, Reclamation Scientist
Horsehead Resource Development Company
St. Simons Island, Georgia 31522
INTRODUCTION
Zinc smelting has taken place in Palmerton, Carbon County, Pennsylvania (USA), since 1898. Two
smelters, the second beginning operation in 1912, located at the base of Blue Mountain, operated
continuously until 1980, when primary zinc smelting was terminated. Emissions from the roasting,
sintering, and smelting of zinc sulfide ores contributed to the defoliation of several thousand acres of
adjacent land.1,2
During the years of active smelting, high levels of S02 were emitted into the atmosphere. In 1962,
S02 emissions varied between 3,300 and 3,600 lb/hr, and it has been assumed that this rate had been
essentially the same since 1918, since there had been no major process changes.3 By 1970, following
the installation of pollution control devices, S02 emissions had declined to an average of 1,400 lb/hr. i
Particulates of cadmium, lead and zinc were also emitted, which build up in the soil at extreme levels.
Historic estimates of total metals emitted are: cadmium — 3,740 tons or 47 tons/year; lead — 7,560 tons
or 95 tons/year; and zinc-286,000 tons or 3,575 tons/year.'*
In addition to the pollutants being emitted from the smelters, Blue Mountain has a history of burns
and logging. By the time the original forest was killed by the S02, there were high enough levels of Cd,
Pb, and Zn in the soil to prevent regeneration. Metals levels are so high that microbial activity has
ceased, and trees that have been dead for 20 or more years cannot decompose.
Typical soil concentrations of zinc range from 10 to 300 mg/L5, while concentrations measured on
Blue Mountain varied between 26,000 mg/L* to 80,0002. Typical soil concentrations of cadmium
range from 0.1 to 7.0 mg/L5, and concentrations measured on Blue Mountain range from 900 mg/L'
to 1,500 mg/L2 . Lead has been reported in concentrations as high as 6,475 mg/L.7
Following the death of the forest, severe soil erosion occurred, and to date it appears that between
12 and 24 inches of topsoil have been removed from the site. As the soil eroded, rock layers emerged,
slowing further movement. The metals levels in the upper 6 to 8 inches of soil remain at toxic levels,
however.
In December 1982, the U.S. Environmental Protection Agency proposed this site for placement on
the National Priorities List (Superfund) for toxic site cleanup, with final listing in September, 1984.
Numerous remedial alternatives were evaluated, including removal of the top 12 inches of contaminated soil, which contains leachable metals. Removal cost, without revegetation, was estimated as
high as $1.3 billion.4 In addition to the contaminated soils on the mountain, there are approximately
33,000,000 yds' of metal-laden smelting residues in a bank 2>/2 mi. long at the base of the mountain.
Removal cost estimates for the cinder bank range from $1.5 to $2.8 billion, and could take from 29 to
45 years to complete, assuming there would be a place to dispose of it. Because of the unreasonable
high environmental and economic costs associated with removal, it was decided to attempt to stabilize
the metals in situ through proper pH management and revegetation.
There are many similar problems associated with smelter emissions in the United States and abroad.
Gale and Wixson.s Wixson and Bennett,' Jackson and Watson,10 Jennett et al,11, Jennett and Foil,12
Kearney et al,13 and Bolter et al,14 all report very similar problems with zinc and cadmium pollution
associated with lead and zinc smelting operations in and around Iron County, Missouri. Walsh and
Bissell15 report sulfur dioxide and heavy metal damage to the forests in the vicinity of a copper smelter
near Anaconda, Montana. In the vicinity of a smelter in Kellogg, Idaho, Ragaini et al," Hansen and
Mitchell,17 and Carter and Loewenstein,18 all report great quantities of S02, Zn, Cd, and Pb having
been emitted during the smelting process, thus causing total destruction of nearby vegetation.
44th Purdue Industrial Waste Conference Proceedings, © 1990 Lewis Publishers, Inc., Chelsea, Michigan 48118.
Printed in U.S.A.
75