Litter leachates from trees are watershed sources of disinfection by-product (DBP) precursors. The tree species is an important factor in determining the amount of chlorine reactive natural organic matter (NOM) leached. In this study, slash pine and schima superb, two common vegetations grown in subtropical climate region, were selected and litter from leaves and soils was extracted, characterized, and evaluated as the potential DBP precursors. The leached litter had the DOC yields of 10.4 mg-DOC/g-dry weight of litter for pine and 38.9 for superb. After one-month biodegradation period, DOC concentrations decreased by 87.8%. SUVA values increased with increasing biodegradation period. Fluorescence analysis indicated the residual NOM transformed during biodegradation for the tree litter leachates was more aromatic and more humic than the fresh leachate. THM formation during chlorination showed an increase followed by a decrease trend with increasing biodegradation period, as Figure 1a shows. Interestingly, trichloronitromethane (TCNM) concentrations increased with increasing biodegradation period (Figure 1b). HAN formation showed different trends for the two species (Figure 1c). Meanwhile, DBP formation of the leached NOM during chloramination exhibited different formation trend from that during chlorination (figure not shown). THM showed continuous increase with increasing biodegradation time. 

Characters and DBP formation of natural organic matter from litter lechates of trees

248th National Meeting (2014)

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