Resumen
Soils are the ultimate examples of physically and chemically irregular mixtures. They are also dynamic. Early investigators consequently did not understand the physical chemistry of pesticides in soil and water. By taking shortcuts instead of trying to understand the physical chemistry, they measured the wrong variables, used the wrong units, calculated the wrong parameters, and totally ignored chemical stoichiometry. Theoretical concepts for the physical chemistry of pesticides in soil have been published during the last quarter century. They are experimentally supported. Yet, chemically incorrect descriptions persist in the literature to this day. That has serious environmental and economic consequences. In particular, government regulators make legally binding pesticide decisions based on computer predictions that are wrong by 1 to 3 orders of magnitude. This needs the attention of scientists, governments, and multinational corporations.