1. Czech Univ. of Life Sciences in Prague; Dep. of Soil Science and Geology; Kamýcká 129 16521 Prague 6 Czech Republic
2. Czech Hydrometeorological Institute; Dep. of Water Quality; Na Šabatce 17 14306 Prague 4 Czech Republic
3. Univ. of California Riverside; Dep. of Environmental Sciences; 900 University Ave., A135 Bourns Hall Riverside CA 92521 USA