AWWA ACE90038

The interaction of a pollutant with dissolved organic material (DOM) can alter the state of the pollutant, thereby changing its behavior, particularly in regards to transport and fate. For example, the ultimate fate of an organic pollutant in the subsurface environment is primarily a function of its susceptibility to microbial degradation. DOM can interfere with that degradation for a number of compounds. The purpose of this study was to determine the equilibrium distribution and behavior of a model-chlorinated aromatic compound (2,4,6- trichlorophenol [TCP]) sorbed to dissolved humic acid, particularly its bioavailability for microbial degradation. A 3-phase equilibrium model that incorporated the pollutant-dissolved organic material sorption phase was used to describe the distribution of 2,4,6-TCP. The study summarized here examined only the solution phase portion of the model. It was found that dissolved humic acid can sorb 2,4,6-TCP, perhaps altering its transport. Biodegradation of humic acid-sorbed 2,4,6-TCP is very slow and appears linear.