This review of absorbable organic halogens (AOX) is part of the overall research effort of the British Columbia Ministry of Environment, Lands and Parks to support the establishment of regulatory controls for effluents being discharged from pulp mills in BC. The complexity and variability involved in bleached kraft pulp production leads to the formation of several hundred structurally diverse chlorinated organic compounds, many of which have not been identified. The amount and nature of chlorinated organic substances discharged from a mill depends largely on the use of different process technologies and primary and secondary effluent treatment systems. Specific chlorinated organic substances which have been shown to be toxic, bioaccumulative, and/or persistent require regulation because they may adversely affect human and environmental health. The purpose of this review is to characterize AOX in an attempt to underscore the significance of using the AOX parameter to regulate discharges of chlorinated organic compounds from bleached kraft pulp mills. The formation of chlorinated organic substances, the effluent composition represented by AOX, and the relationship between AOX measurements and toxicity will be reviewed. The environmental fate of AOX compounds will also be discussed.
McKinnon, L.M. 1994. AOX as a Regulatory Parameter: A Scientific Review of AOX Toxicity and Environmental Fate. BC Ministry of Environment, Lands and Parks