Environ. Sci. Technol. 1093, 27, 2450-2455
Chlorinated Anisoles and Veratroles in a Canadian River Receiving Bleached Kraft Pulp Mill Effluent. Identification, Distribution, and Olfactory Evaluation Brlan G. Brownlee,'vt Gordla A. MacInnls,t and Lelgh R. Notons
Rivers Research Branch, National Water Research Institute, Environment Canada, 867 Lakeshore Road, Burlington, Ontario L7R 4A6, Canada, and Environmental Quality Monitoring Branch, Environmental Assessment Division, Alberta Environment, 9820-106 Street, Edmonton, Alberta T5K 2J6, Canada OH
One chlorinated anisole and three chlorinated veratroles have been identified in extracts of Athabasca River water collected in the winter downstream from a bleached kraft pulp mill effluent. Their potential for causing off-flavors in the receiving waters was evaluated. The average concentration of 2,4,6-trichloroanisole was about 1ng/L, close to the odor threshold concentration in water. The average concentrations of 4,5-dichloroveratrole, 3,4,5trichloroveratrole, and tetrachloroveratrole were 7,7, and 1ng/L, respectively, 2-4 orders of magnitude below their odor threshold concentrations. Chemical structure appears to be more important than volatility from water (Henry's constant) in determining odor threshold concentration. Olfactory gas chromatography showed several odor peaks in these extracts in addition to the chlorinated anisole and veratroles. Several of these compounds were found as far as 1100 km downstream from the pulp mill, consistent with field observations of odor in this river during the ice-covered winter period.
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Introduction Chlorinated anisoles and veratroles are an important family of environmental contaminants because of their toxicity, bioaccumulation, and potential for causing offflavors in water and fish. One source of these compounds to receiving waters is the effluent from pulp and paper mills using chlorine bleaching. Trace amounts of 43dichloroveratrole (45DCV), 3,4,5-trichloroveratrole (345TCV), and tetrachloroveratrole (TeCV) have been found in bleached kraft mill effluent (BKME) (1-4). BKME also contains chlorinated phenols, guaiacols, and catechols (5, 6) which can be biologically methylated to the corresponding anisoles and veratroles (Figure 1)during effluent treatment or in receiving waters (2, 7,8). Chlorinated anisoles are typically several orders of magnitude more potent odor compounds than the corresponding chlorinated phenols (9, IO), and as a group, they possess musty odors (11-13). Several of them have very low odor threshold concentrations (OTC) in water (11-13). For example, 2,4,6-trichloroanisole (246TCA) has a reported OTC of
