Published online by Cambridge University Press: 12 June 2017
Herbicides may be exposed to a broad range of anaerobic conditions in the environment. This range can extend from weakly reducing conditions within typically aerobic compartments to stable, strongly reducing conditions in sites well removed from oxidative conditions. Currently, Federal Insecticide Fungicide and Rodenticide Act (FIFRA) regulatory guidelines specify the design criteria for guideline studies that frequently result in highly stable, strongly reducing test systems. These test systems do not simulate environments where herbicides are likely to occur. Design criteria for anaerobic aquatic test systems can influence the nature of the results of anaerobic aquatic metabolism studies as well as the relevance of these results to natural environmental processes. Design criteria which should be considered are the effects of sediment to water ratio, establishment of an anaerobic system, monitoring the reducing potential (Eh) of the system and the system Eh-pH relationship. These criteria influence how results are interpreted and the extrapolation of data to field environments where herbicides are likely to occur.