1. Pennsylvania State Univ.; Dep. of Ecosystem Science and Management; 116 ASI Building University Park PA 16802 USA
2. Dep. of Chemistry; Univ. at Buffalo, The State University of New York; Buffalo NY 14260 USA
3. Institute of Soil, Water and Environmental Sciences; Volcani Center; Agricultural Research Organization; P.O. Box 6 Bet Dagan 50-250 Israel
4. USDA-ARS, Agroecosystem Management Research Unit; 251 Filley Hall, UNL East Campus Lincoln NE 68583 USA
5. Water Resources Research Center; University of Arizona; 350 N. Campbell Ave. Tucson AZ 85719 USA
6. Civil and Environmental Engineering, Virginia Tech; 403 Durham Hall Blacksburg VA 24061 USA
7. Environmental and Occupational Health Services, Box 357234; Univ. of Washington; 1959 NE Pacific St. Seattle WA 98195
8. USDA-ARS, U.S. National Poultry Research Center; 950 College Station Rd. Athens GA 30605 USA
9. Nebraska Water Center; School of Natural Resources, Univ. of Nebraska-Lincoln; Lincoln NE USA
10. USDA-ARS, Northwest Irrigation and Soils Research Laboratory; 3793 N. 3600 E. Kimberly ID 83341 USA