Formation and determination of organohalogen by-products in water - Part I. Discussing the parameters influencing the formation of organohalogen by-products and the relevance of estimating their concentration using the AOX (adsorbable organic halide) meth

Halogen-based oxidants are widely used in water treatment processes in order to inactivate pathogenic microorganisms. They react with naturally occurring organic matter as well as with other contaminants, leading to the formation of a wide range of unwanted by-products including organohalogen by-products (OXBPs), which have shown toxic properties. The quantity of OXBPs in a water sample can be estimated by a parameter called AOX (halogenated organic compounds adsorbable on activated carbon). Despite the growing number of quantified OXBPs, the material balance (percentage of known OXBPs measured individually divided by the AOX value) indicates that a significant portion of OXBPs remains unknown. This lack of knowledge is a barrier in the assessment of the effects of water treatments on ecosystems and human health. This manuscript is the first part of a review trio on OXBPs; the 2d and 3rd articles are devoted to OXBPs extraction processes and analytical techniques, respectively.