Historical Use of Lead Arsenate and Survey of Soil Residues in Former Apple Orchards in Virginia
HISTORICAL USE OF LEAD ARSENATE AND SURVEY OF SOIL RESIDUES IN FORMER APPLE ORCHARDS IN VIRGINIA by Therese Nowak Schooley Thesis submitted to the faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN LIFE SCIENCES in Entomology Michael J. Weaver, Chair Donald E. Mullins, Co-Chair Matthew J. Eick May 4, 2006 Blacksburg, Virginia Keywords: arsenic, lead, lead arsenate, orchards, soil residues, historical pesticides HISTORICAL USE OF LEAD ARSENATE AND SURVEY OF SOIL RESIDUES IN FORMER APPLE ORCHARDS IN VIRGINIA Therese Nowak Schooley Abstract Inorganic pesticides including natural chemicals such as arsenic, copper, lead, and sulfur have been used extensively to control pests in agriculture. Lead arsenate (PbHAsO4) was first used in apple orchards in the late 1890’s to combat the codling moth, Cydia pomonella (Linnaeus). The affordable and persistent pesticide was applied in ever increasing amounts for the next half century. The persistence in the environment in addition to the heavy applications during the early 1900’s may have led to many of the current and former orchards in this country being contaminated. In this study, soil samples were taken from several apple orchards across the state, ranging from Southwest to Northern Virginia and were analyzed for arsenic and lead. Based on naturally occurring background levels and standards set by other states, two orchards sampled in this study were found to have very high levels of arsenic and lead in the soil, Snead Farm and Mint Spring Recreational Park. Average arsenic levels at Mint Spring Recreational Park and Snead Farm were found to be 65.2 ppm and 107.6 ppm, respectively.
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