A Thesis Entitled Phytoremediation potential at an inactive landfill in northwest Ohio By Kristopher D. Barnswell Submitted as partial fulfillment of the requirements for the Master of Science degree in Biology __________________________ Advisor: Daryl F. Dwyer __________________________ Graduate School The University of Toledo December 2005 A Thesis Entitled Phytoremediation potential at an inactive landfill in northwest Ohio By Kristopher D. Barnswell Submitted as partial fulfillment of the requirements for the Master of Science degree in Biology ____________________________ __________________________ Jiquan Chen Elliot J. Tramer ____________________________ __________________________ Alison L. Spongberg College of Arts and Sciences ____________________________ Donald J. Stierman The University of Toledo December 2005 Copyright © 2005 This document is copyrighted material. Under copyright law, no parts of this document may be reproduced without the expressed permission of the author. An Abstract for Phytoremediation potential at an inactive landfill in northwest Ohio Kristopher D. Barnswell Submitted as partial fulfillment of the requirements for the Master of Science degree in Biology The University of Toledo December 2005 The King Road Landfill (KRL) received municipal solid waste from 1954 through 1976 that was covered with sandy soil. Concern exists that water may infiltrate through the sandy soil and into the waste thereby producing leachate. Evapotranspiration (ET) covers are a new approach to prevent infiltration of precipitation into landfills. They are less expensive than conventional caps and may perform comparably. The plants chosen to prevent leachate formation can also be used to restore landfills to native habitat. In this study, 191 vascular plant species were identified within 56 plots (each 167 m2) at the KRL and questioned for their appropriateness in creating an ET cover and restoring native habitat. Among these, 117 species were deemed inappropriate (i.e., either not native to iv Ohio, have annual/biennial growth, prefer wetland habitat, and/or have vine root systems). Of the remaining 74 native plants, 18 were either widely distributed, woody species with a high density (> 45 per hectare), or understory species with significant ground coverage. These species were considered established at the KRL and appropriate for further testing of their transpiration performance as a component in an ET cover. Another goal was to determine if the primarily wooded KRL is suitable as a nature preserve for the Oak Openings Region (OOR). For this purpose, we conducted a second survey in four woodland plant communities representative of the region (8 plots per community): floodplain, sand barren, oak savanna, and deciduous woodland located in the Oak Openings Metropark (OOMP). Within the two surveys, 11 threatened and endangered plant species were observed, such as Lupinus perennis and Eupatorium album. The plant community of the KRL was in early stages of development and demonstrated little resemblance to the four OOMP woodland communities. The KRL contained young plants (70% of the woody species had diameters at breast height (dbh) between 2.5 and 10 cm) that have fast growth rates and short lifespans (e.g., Populus deltoides, Robinia pseudoacacia, and Ulmus pumila), whereas plants at the OOMP were comparatively mature (43% of woody species had dbh measurements > 10 cm), having slow growth rates and long lifespans (e.g., Hamamelis virginiana and Quercus spp.). v The Jaccard index was used to measure the similarity in species composition between the KRL and the OOMP. The highest value was only 0.32, indicating the plant communities at the two sites had little similarity, and suggests they may be at different stages of development. Comparative values for species richness, Shannon’s index, Simpson’s index, and evenness at the KRL and the OOMP were, respectively; 24.15 + 0.76 vs. 14.84 + 0.81; 2.51 + 0.06 vs. 2.01 + 0.09; 0.87 + 0.01 vs. 0.76 + 0.03; and 0.83 + 0.01 vs. 0.79 + 0.03, demonstrating greater diversity at the KRL, which further signifies its early successional stage compared to the OOMP. In summary, the KRL is in early stages of succession and is developing into a woodland plant community. Seeding the landfill with native plant species may be practical to guide its successional pathway towards a plant community that is appropriate for an ET cover and habitat restoration. The 11 threatened and endangered species ideally would be included in the restoration process and advocate the idea of the KRL being used as a nature preserve for plants that otherwise may be lost from this region. vi Acknowledgements I thank my advisor Dr. Daryl F. Dwyer for giving me the opportunity of this great experience. Your guidance and patience were among the few things that allowed me to reach my goals. I have the utmost respect for you, and your friendship will forever be cherished. The forests out west probably would have given me a beating if it were not for you. I also express gratitude to my committee members: Dr. Jiquan Chen, Dr. Alison Spongberg, Dr. Don Stierman, and Dr. Elliot Tramer; to the people of the Environmental Remediation and Restoration Lab (ERRL): Colin, Issmat, Joe, Jordan, Josh, Pam, and Rock for assistance and criticism in this study; Traci Walker for field work assistance; the Lake Erie Center, especially Jeff and Pat for their additional efforts and lunchtime Jeopardy games. I appreciate the northwest Ohio EPA Division, Lucas County authorities, and the Metroparks of the Toledo Area for access to the field sites; John Jaeger and Tim Walters for assistance in the identification of plants; Tom Hays and Mike Momenee for information of the landfill’s history. Finally, I thank my family and friends. My parents have been extremely generous and encouraging throughout this project. My wonderful fiancée Crystal, you have been the most supportive individual during this long endeavor, and for that, I love you so much more. vii Table of Contents Abstract iv Acknowledgements vii Table of Contents viii List of Figures ix List of Tables x Chapter One - Introduction 1 Chapter Two - Materials and Methods 4 Chapter Three - Results 18 Chapter Four – Discussion 42 References 54 Appendix – Catalog of vascular flora identified at the King Road 62 Landfill and the selected plant communities of the Oak Openings Metropark viii List of Figures Figure 1. Areas of operation at the King Road Landfill. 6 Figure 2. Aerial photograph of the King Road Landfill taken in 1957. 7 Figure 3. Aerial photograph of the King Road Landfill taken in 1963. 8 Figure 4. Aerial photograph of the King Road Landfill taken in 1972. 9 Figure 5. Aerial photograph of the King Road Landfill taken in 2001. 10 Figure 6. Aerial photograph of the Oak Openings Metropark. 12 Figure 7. Vegetation survey design. 14 Figure 8. Total number of plant species identified by plot. 36 Figure 9. Shannon’s Index measuring species diversity by plot. 37 Figure 10. Simpson’s Index measuring species diversity by plot. 38 Figure 11. Species evenness by plot. 39 ix List of Tables Table 1. Densities of woody plant species. 24 Table 2. Mean percent ground coverage of understory species. 26 Table 3. Jaccard index values. 34 Table 4. Threatened and endangered plant species of Ohio. 41 Table 5. Diameter at breast height distributions for woody plant species. 50 Table 6. Diameter at breast height for woody plant species. 50 x Chapter One Introduction Landfills without constructed barriers that prevent water from percolating through the contained wastes may generate leachate that contaminates adjacent groundwater (Cozzarelii et al., 2000; Yoon et al., 2003). Conventional caps (USEPA, 1993) and evapotranspiration (ET) covers (Hauser et al., 2001) can be placed atop the waste to limit water infiltration. Whereas conventional caps remove precipitation as runoff, ET covers store precipitation in the rhizosphere where it is later transpired to the atmosphere. When ET covers function correctly, the rates of transpiration substantially reduce the infiltration of water into the landfill (Rock, 2003; Licht et al., 2004). ET covers are often less expensive than conventional caps (Dwyer, 1998) and offer additional benefits such as accelerated waste stabilization, reduction in greenhouse gas production, habitat enhancement, and improved aesthetics (Licht et al., 2001). The U.S. Environmental Protection Agency (EPA) initiated the Alternative Cover Assessment Program (ACAP) in 1998 to compare the performances of ET covers and conventional caps (Albright et al., 2003). As 1 described by ACAP, these covers consist of a thick soil layer, with dense vegetation that includes annual and perennial grasses, forbs, shrubs, and hybrid poplars (Bolen et al., 2001; Roesler et al., 2002; Rock, 2003). ET covers were noted to function comparably, except in relatively humid environments (> 20 cm precipitation/year). A general conclusion from the program suggests that ET covers require well-designed, site-specific features (Albright, et al., 2004), which should include the judicious selection of plants that are adapted to function within a given environment and climate. With proper vegetation selection, leachate formation could be reduced to the minimum, acceptable levels. Although, the comparative advantages of an ET cover are difficult to ignore, their application is infrequent in humid regions due to limited cases in which their performance was comparable to conventional caps (Bolen et al., 2001; Albright and Benson, 2002; Benson et al., 2002; Albright et al., 2004). The current study is part of an assessment of the plant cover on the inactive King Road Landfill (KRL) in northwest Ohio. While active, the KRL was covered with sandy soil on which diverse vegetation has emerged since operations ceased in 1976. Removal of the existing plant cover and the installation of a conventional cap have been suggested to limit water infiltration to the waste. The goal of this study was to analyze the existing vegetation of the landfill for native-perennial plant species appropriate for an ET cover.