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Unclassified Unclassified UnclassifiedUnlimited 42Michael T. Montgomery
202-404-6419Mineralization rates of 14C-TNT, -DNT, and -DAT were measured in surface sediments, with depth in sediment cores, and in the water column during 12 research cruises over the past 4 years in the San Francisco Bay, Chesapeake Bay, and Hawaii. Mineralization rates were also compared to uptake and incorporation rates of TNT, DNT, and DAT into the natural microbial assemblage. In general, the bacterial mineralizations rates were similar, or an order of magnitude faster, than those for organic hydrocarbons measured at the same time. Using seawater sampled from a historical UXO field, we found that while bacterial mineralization was rapid (>1 ug L-1 d-1, unfiltered water in dark), photodegradation was even faster (16 ug L-1 d-1, filtered water in light) and the combination of light and unfiltered water was greater than the sum of the two rates (103 ug L-1 d-1), suggesting either that the prescnce of active phytoplankton is important or photodegradation enhances bacterial mineralization.