Environmental Engineering Reference
In-Depth Information
chapter one
Introduction to recalcitrant
compounds
Jeffrey W. Talley
Contents
1.1 Introduction .................................................................................................... 1
1.2 Relevance......................................................................................................... 2
1.3 Biodegradation and bioavailability............................................................. 3
1.4 The sequestration of recalcitrant compounds ........................................... 4
References................................................................................................................. 7
1.1
Introduction
Bioremediation is defined by the U.S. Environmental Protection Agency
(EPA) as a managed or spontaneous process in which microbiological pro-
cesses are used to degrade or transform contaminants to less toxic or nontoxic
forms, thereby remedying or eliminating environmental contamination
(EPA, 1994). These microbiological processes may reduce hydrocarbon con-
centrations in various types of soils and sediments to levels that no longer
pose an unacceptable risk to the environment or human health (Linz and
Nakles, 1997). However, hydrocarbons that remain in treated soils and sed-
iments still might not meet stringent regulatory levels, even if they represent
site-specific, environmentally acceptable endpoints (NRC, 1997). This unre-
solved issue of the availability of residual hydrocarbon contaminants is the
focus of this work.
There is a great need to understand contaminant soil-sediment interac-
tions and their effect on bioavailability and toxicity (NCR, 1997). This is
especially true for recalcitrant compounds. The adherence and slow release
of recalcitrant compounds from soils and sediments is an obstacle to
1
