Response of Four Turfgrass Cultivars to Limestone and Biosolids-Compost Amendment of a Zinc and Cadmium Contaminated Soil at Palmerton, Pennsylvania Yin-Ming Li,* Rufus L. Chaney, Grzegorz Siebielec, and Beverly A. Kerschner ABSTRACT Revegetation treatments (NPK fertilizer, limestone plus NPK fer- tilizer, or composted iron-rich limed biosolids) were evaluated on severely Zn phytotoxic soils near a former smelter. Soils contained 15 500 mg Zn and 158 mg Cd kg -t and initial soil pH was 6.0. Zinc- resistant ’Merlin’ red fescue (Festuca rubra L.) was compared with ’Bonanza’ and ’Kentucky-31’ tall fescue (Festuca arundinacea Schreb.) and ’Touchdown’ Kentucky bluegrass (Poa pratensis L.) for leaf phytotoxicity symptoms, rapidity of achieving cover, persistence of cover, and metal accumulation. Biosolids compost morestrongly reduced soluble Zn and Cd, resulting in effective remediation of Zn phy~otoxicity that persisted for the 4 yr of this test. ’Merlin’red fescue showed remarkable exclusion of Zn and Cd (201-446 mg kg -t Zn and 0.9-2.7 mg kg -~ Cd in dry shoots from treated plots) but grew slowly and made poor lawns. ’Kentucky-31’ tall fescue plants grew rapidly and reached almost 100%cover within 3 mo in compost treatment plots, but the Zn exceeded phytotoxic threshold levels (>500 mg Zn kg-~). ’Bonanza’ tall fescue and ’Touchdown’ Kentucky bluegrass had good growth performanceand contained lower concen- trations of Zn and Cd than ’Kentucky-31’ tall fescue on biosolids- compost amended treatments and were more suitable as a lawn and/ or revegetation crop. After the first year of the study, the commercial turfgrasses survived only on the biosolids-compost plots. The combi- nation of calcareous soil pH and higher organic matter, Fe, andphos- phate levels of biosolids-compost amended plots improved the overall success of vegetation establishment and allowed important turfgrasses to revegetate highly Zn-contaminated soils. R~ VEGETATION of severely phytotoxic Zn-contami- nated soil is important to prevent dispersal of the contaminants to the surrounding area and to recover the natural beauty of the environment. Highly Zn-con- taminated soils (often acidic from SO2)usually lack veg- etative cover due to phytotoxicity; low concentrations of soil Zn can be phytotoxic at more acidic sites (Cha- ney, 1993; Li and Chaney, 1998; Brownet al., 1998). Zinc contamination around smelters has caused barren landscapes at many locations. The Palmerton Zinc Su- perfund Site surrounds a former zinc smelting facility located in Palmerton, PA. Zinc smelting began in 1898 and operated continuously until 1980. Smelter stack emissions contained high concentrations of Zn and Cd oxides. During operation, the primary Zn smelter emit- ted 3575 Mgof Zn, 47 Mgof Cd, and 95 Mgof Pb per year for more than 80 yr (USEPA, 1987). High levels of these pollutants were carried as far as 50 kmfrom the plant (Tan, 1988) and were detected above background Y.-M. Li and R.L. Chaney, USDA-ARS, Environmental Chemistry Lab., Bldg. 007, 10300 Baltimore Ave., Beltsville, MD 20705-2350; G. Siebielec, Institute for Soil Science and Plant Cultivation, Pulawy, Poland; B.A. Kerschner, Zinc Corporation of America, 480 Delaware Ave., Palmerton, PA 18071. Received 11 Feb. 1999. *Corresponding author (yli@ba.ars.usda.gov). Published in J. Environ. Qual. 29:1440-1447 (2000). levels in forest organic layers more than 100 kmfrom the plant (Andresen et al., 1980). The metal analyses of the forages sampled on three farms near Palmerton showed that forages were quite enriched in Zn and Cd. Forage Pb was high, up to 25 mg kg -1 at one farm (Chaney et al., 1988). In the vicinity of the smelter, the steep hillsides of Blue Mountain and Stony Ridge, soil concentrations of Zn reached 26 000 to 80 000 mg kg -1 while concentrations of Cd reached 900 to 1500 mg kg -1 (Buchauer, 1973; Jordan, 1975; Beyer, 1988). The combination of high soil Zn and acidic soil pH was strongly phytotoxic in the Palmerton environment. Microbial activity was also reduced (Strojan, 1978). The absence of a vegetative cover facilitated dispersion of the highly contaminated soils and forest organic layer by wind and water erosion. In the town of Palmerton, lawn and garden soils commonlycontained 10 000 mg Zn kg -1 and 100 mg Cd kg -1 (Chaney et al., 1988). Because of the high cost of removal and replacement of contaminated surface soils, phytostablization (using soil amendments and plants to immobilize or render soil pollutants less toxic without removing the contaminated soil) appears to be a more practical remediation ap- proach (Chaney et al., 1999; Li and Chaney, 1998). Homeowners in the Palmerton area repeatedly noted that new sod or seedings were soon killed (Chaney et al., 1988; Baker and Bowers, 1988). Some residents gave up on lawn grasses and covered their soil with stones, peat moss, or wood chips (Chaney et al., 1988; Cha- ney, 1993). Twoapproaches to revegetation of such severely phy- totoxic soils have been successful in previous studies: using genetically metal-resistant grass genotypes with regular fertilization (Smith and Bradshaw, 1979; McNeilly and Johnson, 1978, 1981; Johnson and Brad- shaw, 1979) and incorporation of "tailor-made" biosol- ids and composts that contain enough limestone equiva- lent to makethe soil calcareous and high in phosphate, Fe (to increase metal sorption capacity), and organic matter (to improve soil fertility) so that plants with normal metal tolerance can grow and persist on the soil (Sterrett et al., 1996; Chaney et al., 1999). Smith and Bradshaw(1979) reported that planting metal-resistant turfgrass and fertilizing regularly provided effective veg- etative cover and site stabilization at mine waste depos- its. Three grass cultivars that could be used for revegeta- tion [’Goginan’ common bentgrass (Agrostis capillaris L.) for acid lead and zinc wastes; ’Merlin’ red rescue for calcareous lead and zinc wastes; and ’Parys’ common bentgrass for copper wastes] have been released (Smith and Bradshaw, 1979; McNeilly and Johnson, 1978, 1981; Johnson and Bradshaw, 1979). The other successful approach to remediation, mak- ing soils calcareous and improving soil fertility and phys- 1440