Growth in the numbers of organic chemicals during recent decades has been extraordinary. Most are complex compounds that are released directly and/or indirectly to the surrounding environment. A view is emerging in relation to environmental protection and hazardous substance management that (1) some organic chemicals and/or organic leachates from solid waste materials and contaminated sediment/soil sites are of such extreme environmental concern that all use should be highly controlled including isolation for disposal; and (2) most hazardous substances are of sufficient social value that their continual use, production and disposal are justified. For these chemicals their types, sources, fate, behavior, effects and remediation at solid- aqueous phase interfaces must be fully assessed and understood. This assessment and understanding are essential for society to accept risks of adverse ecological or human health effects.