Leaching potential of turf care pesticides: a case study of Long Island golf courses

Pesticides used to maintain golf course turf can threaten ground water. This concern is particularly important in most of New York's Long Island, where generally sandy soils overlie a sole source aquifer. This study uses two methods to evaluate the potential for pesticides that are commonly used on Long Island's golf courses to leach to ground water. Adapting the Pesticide Root Zone Model (PRZM), Release 1, for dense turf and applying site-specific soil data, certain pesticides, including metalaxyl and trichlorfon, are identified as potential problem leachers. PRZM simulations also identify the Long Island soils, including the sandy Plymouth and Carver soils, which are most vulnerable to leaching. When adequate input data for PRZM is unavailable, the ground water ubiquity score (GUS) method may be useful. GUS leachability classifications of pesticides commonly applied on Long Island golf courses, and of pesticides actually detected in ground water samples taken on Long Island, agree with PRZM predictions and the field data. The GUS method is applied to the evaluation of the leaching potential of pesticide degradation products (DCPA, maneb, and mancozeb metabolites), and the degradation products are shown to be a greater threat to ground water than their parent compounds. These methods are potentially useful in designing ground water monitoring programs and for guiding the pesticide use and selection decisions of golf course managers