Effect of cellulose/hemicellulose and lignin on the bioavailability of toluene sorbed to waste paper

Paper constitutes about 38% of municipal solid waste, much of which is disposed of in landfills. Sorption to such lignocellulosic materials may limit the bioavailability of organic contaminants in landfills. The objective of this study was to identify the effect of individual biopolymers in paper on toluene sorption and bioavailability by subjecting fresh and anaerobically degraded office paper and newsprint to enzymatic hydrolysis and acid hydrolysis. Enzymatic degradation of cellulose and hemicellulose had no effect on toluene bioavailability. In contrast, acid-insoluble lignin controlled toluene sorption and bioavailability for both fresh and degraded newsprint. Acid-insoluble lignin could explain only 54% of the toluene sorption capacity of degraded office paper however, suggesting that crude protein and/or lipophilic organic matter were also important sorbent phases. Toluene sorbed to degraded office paper was also less bioavailable than toluene sorbed to an equivalent mass of lignin extracted from this sorbent. The latter result suggests that a fraction of toluene sorbed to degraded office paper may have been sequestered by lipophilic organic matter. The sorption and bioavailability data indicate that the preferential decomposition of cellulose and hemicellulose relative to lignin in landfills should not decrease the overall toluene sorption capacity of paper waste or increase the bioavailability of sorbed toluene.