Influence of Dissolved Organic Matter and Fe(II) on the Abiotic Reduction of Pentachloronitrobenzene

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• 作者：J. Alexandra Hakala ; Yu-Ping Chin ; Eric J. Weber
• 刊名：Environmental Science & Technology
• 出版年：2007
• 出版时间：November 1, 2007
• 年：2007
• 卷：41
• 期：21
• 页码：7337 - 7342
• 全文大小：150K
• 年卷期：v.41,no.21(November 1, 2007)
• ISSN：1520-5851

文摘

Nitroaromatic pesticides (NAPs) are hydrophobic contaminants that can accumulate in sediments by the depositionof suspended solids from surface waters. Fe(II) anddissolved organic matter (DOM), present in suboxic andanoxic zones of freshwater sediments, can transform NAPsin natural systems. We studied the reduction of pentachloronitrobenzene (PCNB) to pentachloroaniline (PCA)in controlled studies using Fe(II) and surface water DOMisolates from Pony Lake, Antarctica, and Suwannee River,GA, in unfiltered and 0.45 m filtered solutions. Weobserved rapid reduction of PCNB to PCA in the presenceof Fe(II) and DOM (t_1/2 30 min to 4 h) and very limitedreduction in DOM-only systems. DOM in unfiltered systemsinhibited iron colloid formation and potentially limited theformation of reactive Fe(II)-iron colloid surface complexes,causing reductive transformation in Fe(II)-DOM mediato be slower in some cases relative to Fe(II)-only controls.Conversely, in 0.45 m filtered solutions, PCNB reductionin Fe(II)-DOM media was faster than the Fe(II)-only controls,suggesting that DOM enhances the reductive capacityof Fe(II) in the absence of iron colloids. This work showsthat DOM may significantly affect the reactivity of Fe(II)toward NAPs under suboxic and anoxic conditions in naturalwetland sediments.