Yield of trihalomethanes and haloacetic acids upon chlorinating algal cells, and its prediction via algal cellular biochemical composition

The major objective of the present study was to investigate the contribution of major biomolecules, including protein, carbohydrates and lipids, in predicting DBPs formation upon chlorination of algal cells. Three model compounds, including bovine serum albumin (BSA), starch and fish oil, as surrogates of algal-derived proteins, carbohydrates and lipids, and cells of three algae species, representing blue-green algae, green algae, and diatoms, were chlorinated in the laboratory. The results showed that BSA (27 μg mg−1 C) and fish oil (50 μg mg−1 C) produced more than nine times higher levels of chloroform than starch (3 μg mg−1 C). For the formation of HAAs, BSA was shown to have higher reactivity (49 μg mg−1 C) than fish oil and starch (5 μg mg−1 C). For the algal cells, Nitzschia sp. (diatom) showed higher chloroform yields (48 μg mg−1 C) but lower HAA yields (43 μg mg−1 C) than Chlamydomonas sp. (green algae) (chloroform: 34 μg mg−1 C; HAA: 62 μg mg−1 C) and Oscillatoria sp. (blue-green algae) (chloroform: 26 μg mg−1 C; HAA: 72 μg mg−1 C). The calculated chloroform formation of cells from the three algal groups, based on their biochemical compositions, was generally consistent with the experimental data, while the predicted values for HAAs were significantly lower than the observed ones. As compared to humic substances, such as humic and fulvic acids, the algal cells appeared to be important precursors of dichloroacetic acid.