Biodegradation

In the review of Alkylphenol Ethoxylates (APE) biodegradation, the distinction between primary and ultimate biodegradation follows the definitions of Swisher (1987). Primary degradation describes the loss of a measurable chemical characteristic of a compound while ultimate biodegradation describes the mineralization of a compound to CO₂, H₂O, and inorganic substances. Under anaerobic conditions, CO₂ and methane are generated. The biodegradation or removal of APE surfactants has been extensively studied. It is generally agreed that APE undergo primary degradation under a variety of field conditions and test systems, provided sufficient acclimation time has occurred. This chapter summarizes available information on biodegradation or removal under both laboratory and field situations. Although branched OPE and nonylphenol-ethoxylate NPE are currently the only alkylphenol ethoxylates of commercial importance, information on APE with linear alkyl chains is included for comparative purposes.