Where Do Organic Chemicals Found in Soil Systems Come From?

Abstract

This chapter briefly discusses the sources, other than industrial point sources, responsible for the presence of organic chemicals in soil systems. In general, man-made sources of organic chemicals represent a minor contribution with respect to the total mass of organic chemicals in soil. However, chemicals deposited by man-made sources are frequently mistaken for chemicals discharged by onsite industrial or commercial operations. More industrially-derived organic chemicals will be identified as naturally-occurring as our knowledge of the reactivity of those naturally-occurring soil organic chemicals increases. The first source of organic chemicals present in soil is human activities which result in an “across-the-board” type of deposition into or onto soils. The second source of organic chemicals in soil is biota, which fall into two categories: vegetation, and soil fauna and soil flora. Unlike metals which do not change their chemical structure, these naturally-occurring organic chemicals are reactive and, as a result, are transient in soil systems.