Research Product

Microbial degradation of xenobiotic compounds in natural environments is probably the most difficult fate process to study and quantitate. Information necessary to predict biodegradation of a chemical depends on laws of chemistry, the genetic capabilities of the microbial populations, and on conditions in the environment. We have studied degradation of toxicants under conditions that maintain complexities of the natural environment and associated microorganisms. Studies with (NTA) nitrioltriacetic acid demonstrated that this compound, normally biodegradable in freshwater, persists in estuarine environments. The studies illustrate the complex interactions in natural environments that complicate our understanding of biodegradation mechanisms. Interaction with environmental conditions or lack of genetic capabilities within an environment was demonstrated further when freshwater, but not saltwater, microbial populations were shown to adapt within several days to degrade p-nitrophenol rapidly. Differences in chemical structure affect degradation of toxic chemicals in natural media with mixed microbial populations. Such structure range from compounds like methyl parathion, which is substantially metabolized, to dimilin, which partially degrades and yields nonbiodegradable products, to Kepone, which persists intact.