Benzo[a]pyrene (BaP) in sediments is persistent and carcinogenic to organisms. We here investigated how the mineralization of 7-14C-BaP by H2O2 treatment in aged sediments was influenced by the chemical structures, compositions and nanoporosity of sedimentary organic carbon (OC). Unstable OC (USOC), stable OC (SOC), mineral-protected OC (MOC), and chemically resistant OC (ROC) fractions were fractionated in the sediments. The chemical structures and nanoporosity of the ROC fractions were characterized by 13C solid-state nuclear magnetic resonance (NMR) and CO2 adsorption technique, respectively. A first-order, two-compartment kinetics model described the mineralization process very well (R2 &gt;0.980). The BaP mineralization ratios gradually decreased from the estuary samples to the offshore marine samples, contrast to the variation trend of aliphatic contents of ROC. The BaP mineralization ratios were significantly positively correlated with the USOC contents (R2=0.847, p&lt;0.05), suggesting that BaP in USOC was readily oxidized. Significantly negative correlations of the mineralization parameters of BaP with aliphatic-C, alkyl-C, and (CH2)n-C, and Vo (nanopore volumes) values of ROC suggested that the aliphatic moieties and nanoporosity played crucial roles in protecting sorbed BaP from being mineralized by hydroxyl radicals. This study indicated that the important roles of the USOC, and aliphatic moieties and the nanoporosity of ROC in the mineralization of BaP in sediments during the H2O2 treatment.

Effects of compositions and chemical structures of sedimentary organic matter on mineralization efficiency of benzo(a)pyrene by hydrogen peroxide

2019 Spring National Meeting

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