Chlorinated anisoles and veratroles in a Canadian river receiving bleached kraft pump mill effluent. Identification, distribution, and olfactory evaluation

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 1 ng/L, close to the odor threshold concentration in water. The average concentrations of 4,5-dichloroveratrole, 3,4,5-trichloroveratrole, and tetrachloroveratrole were 7,7, and 1 ng/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.