Effects of Zinc Smelter Emissions and Fire on a Chestnut-Oak Woodland

Abstract

Zinc ores have been smelted in Palmerton, Pennsylvania, since 1898. Within 2 km of the primary smelter, up to 8% Zn, 1500 ppm Cd, 1200 ppm Cu and 1100 ppm Pb by weight were found at the surface of the A1 soil horizon. Washed, oven—dried foliage of trees located near the smelters contained up to 4,500 ppm Zn and 70 ppm Cd by weight. The Lehigh Gap area of Blue Mountain near the smelters is sparsely vegetated or completely barren over an area of about 485 ha. Forests in burned and unburned areas were sampled for density and cover of trees, shrub, and herb species. Sassafras albidum and Nyssa sylvatica are the most common tree species in the burned, severely denuded areas; Arenaria patula is the most common herb. Very few tree seedlings are found near the smelters. Species which normally invade burned areas, including Populus tremuloides, Betula populifolia, Comptonia peregrina, and Pteridium aquilinum, are rare or absent at Lehigh Gap. Inhibition of seed germination and/or seedling growth by high levels of soil Zn is probably preventing establishment of these invader species. Quercus rubra and Pinus strobus seedlings planted in pots of high Zn soil collected near the smelters produced much less root and shoot growth than normal. Minimum toxic foliar levels for Q. rubra are approximately 250 ppm Zn and between 5 and 30 ppm Cd. Arenaria patula tolerated 100 ppm Zn in sand culture and a foliar content of 13,000 ppm Zn, and is probably a zinc—tolerant ecotype. Solution concentrations of up to 100 ppm Zn and 10 ppm Cd did not affect seed germination of Q. rubra, B. populifolia, and P. tremuloides, but at these metal concentrations the radicle fails to elongate. Radicle elongation occurs, but is significantly reduced, at > 1 ppm Zn or > 5 ppm Cd in solution culture. Saturation extracts of soils collected 1—5 km from the smelter contained 40—1.6 ppm Zn and 1.0—0.02 ppm Cd; thus only the Zn content of soils within 5 km of the smelter appears high enough to stunt root growth. The combined stresses of high soil—zinc levels plus fire appear to be the primary cause of the vegetation damage at Lehigh Gap. Either stress alone would have caused much less damage. Erosion and desiccation are important secondary factors preventing revegetation of the barren areas.

Wild Ungulate Use of Areas in Southwestern Montana After Fourteen Years of Natural Recovery from Smelter Impacts

“…The deleterious effects of smelter emissions on vegetation have been well documented by authors in several countries (Archibold 1978, Conroy and Kramer 1995, Franzin 1984, Gordon and Gorham 1963, Jordon 1975, Winterhalder 1995a, Yan and Miller 1984. Smelter emissions at Anaconda, in concert with many years of fire, logging, and overgrazing, resulted in significant vegetation loss and erosion on upland areas within several kilometers of the stacks (Oswald 1981).…”

Palmerton Zinc Superfund Site Constructed Wetlands

“…Typical total soil Zn values in and around affected Blue Mountain soils have ranged from 26,000 mg/kg to 80,000 mg/kg Zn (Jordan, 1975). However, more recent surveys show total Zn soil levels ranging from about 5,000 mg/kg to 20,000 mg/kg (Wright, 1988).…”

Reclamation of a Site Near a Smelter Using Sludge/Flyash Amendments: Herbaceous Species

“…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 smelters, both from the coalfired physical plant and from the roasting, sintering, and smelting of zinc sulfide ores contributed to the defoliation of several thousand acres of adjacent land (Buchauer 1971, Jordan 1975). …”

“…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 ppm (Brady 1974), while .concentrations measured on Blue Mountain varied between 26,000 ppm (Strejan 1978) to 80,000 ppm (Jordan 1975). Typical soil concentrations of cadmium range from 0.1 to 1.0 ppm (Brady 1974), and concentrations measured on Blue Mountain range from 900 ppm (Strejan 1978) to 1,500 ppm (Jordan 1975).…”