Although guidance documents exist that deal with aquatic exposure or effect assessments of pesticides, the interaction between these fields of expertise has received relatively little attention within these documents. This insightful work provides the context through which to evaluate these two previously isolated datasets and thereby improve regulatory guidance on the aquatic risk assessment for pesticides. Addressing the shortcomings of current procedures and the uncertainties arising from time-variable surface water exposure profiles, the book presents key parameters for risk assessment, examines aquatic micro- and mesocosms, looks at toxicological modeling, and includes case studies and a glossary of terms.