M. S. MILLS is a research environmental chemist with Zeneca Agrochemicals at the Jealott's Hill Research Station, Bracknell, U.K. Dr. Mills was form erly employed by the U.S. Geological Survey in Lawrence, Kansas, where he r research interests included exploring the mechanisms and applications of solid-phase extraction in environmental chemistry, investigating the orga nic geochemistry of naturally occurring aquatic foams, and the degradation and transport of xenobiotics in the vadose zone. She has contributed numerous publications and oral presentations on these topics over the past five year...