Contaminants:
Lead, Cadmium, Arsenic, Zinc, Copper

Reactive Media:
Limestone

Construction:
Continuous Trench

Point of Contact:
John Banks
USEPA Region 3
Tel: 215-814-3214
Fax: 215-814-3002
Email: banks.john-d@
epa.gov
3HS22
1650 Arch Street
Philadelphia , PA 19103-2029

Construction of a full-scale permeable reactive barrier (PRB) was completed in August 1998 at the Tonolli Superfund Site near Nesquehoning, PA. The Tonolli Corporation operated a battery recycling and secondary lead smelting plant at the site from 1974 until 1986, and currently is responsible for cleanup activities. The presence of elevated dissolved metals in the ground water is attributed to both waste sources and anthropogenic sources from the dumping of battery acid during past site operations, and the acid mine drainage effect of the mine spoils.


The goal of ground-water remediation is to achieve background levels for contaminants in the overburden aquifer. The PRB is being used to remediate ground water contaminated with heavy metals, including lead (Pb), cadmium (Cd), arsenic (As), zinc (Zn), and copper (Cu). Maximum concentrations of these contaminants encountered were 328 µg/L of Pb, 77 µg/L of Cd, 313 µg/L of As, 1,130 µg/L of Zn, and 140 µg/L of Cu.

The contamination is located in coal mine spoil at 0-19 ft and in alluvium from 74-113 ft. No information provided about the lithology between. Ground water in the area flows horizontally southeast toward Nesquehoning Creek. Vertical ground-water flow is downward in the northern portion of the site, and upward in the southern portion of the site, where it discharges to the creek.

To construct the PRB, a ground-water trench, approximately 3 ft wide, 20 ft deep, and 1,100 ft long, was dug using a trackhoe. Trench boxes were installed parallel to the creek along the southern site property boundary.

Results Pending (2000).

Lessons Learned

One-pass trenching equipment was evaluated and determined to be impractical. Problems arose during construction as a result of the presence of rubble and concrete foundations, sloughing of mine spoil, and the close proximity of a railroad spur and an onsite landfill embankment. In addition, the wall was designed to be 1 ft in width but required expansion to 3 ft.