[1] UNIV CALIF RIVERSIDE, DEPT SOIL & ENVIRONM SCI, RIVERSIDE, CA 92521 USA
[2] UNIV LEEDS, SCH CHEM, LEEDS LS2 9JT, W YORKSHIRE, ENGLAND
[3] UNIV OXFORD, ROBERT HOOKE INST, OXFORD OX1 3QZ, ENGLAND
[4] NATL INST STAND & TECHNOL, CTR CHEM KINET DATA, GAITHERSBURG, MD 20899 USA
[5] ETH, EAWAG, SWISS FED INST TECHNOL, CH-8600 DUBENDORF, SWITZERLAND
[6] UNIV GOTTINGEN, INST PHYS CHEM, W-3400 GOTTINGEN, GERMANY