ENVR 90 |
| Nitroaromatic pesticides (NAPs) are hydrophobic contaminants that can be abiotically transformed into their aniline derivatives by Fe(II) and dissolved organic matter (DOM), reductants naturally present in freshwater sediments. We observed reduction of pentachloronitrobenzene (PCNB) to pentachloroaniline (PCA) in filtered freshwater sediment porefluids at pH > 7.0, [Fe(II)] in the 100s of μM, and [DOC] > 1 mM-C. The PCNB reduction rate increased with pH and Fe(II) was necessary for reduction to occur. An experiment conducted with Fe(II)-free cation-exchanged porefluids was non-reactive. Comparison with controlled reactions containing Fe(II) and fulvic acid isolates suggests that reduction occurs by similar mechanisms involving Fe(II) and DOM in natural porefluids. Rate constants reported here are low estimates of actual natural porefluid reductive capacity, as we expect Fe(II) associated with colloidal material to dominate reduction in unfiltered natural porefluids. |
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The C. Ellen Gonter Environmental Chemistry Awards
1:30 PM-4:35 PM, Tuesday, August 21, 2007 Boston Park Plaza -- Beacon Hill Rm, Oral
Division of Environmental Chemistry |