Acute and Chronic Toxicity of Chlorine Dioxide (ClO2) and Chlorite (ClO2ˉ) to Rainbow Trout (Oncorhynchus mykiss) (4 pp)

Abstract

Due to its very reactive nature, chlorine dioxide is rapidly (in a few hours) reduced to chlorite, which is persistent also as a biocide but 16 times less toxic to fish, according to MATC. Therefore, it is much more likely that fish will be exposed to chlorite than to chlorine dioxide in natural waters. Presently accepted, the Maximum-Permitted-Concentration of total residual chlorine (TRC) in waste-water discharging into receiving waters is 0.6 mg/l. If this requirement will not be exceeded, it is unlikely that fish would be exposed to lethal or even to sublethal concentrations of chlorine dioxide or chlorite. Furthermore, chlorine dioxide does not generate toxic nitrogenous (chloramines) or carcinogenic organic residuals (trihalomethanes). All these properties make chlorine dioxide a more promising biocide than chlorine.

Chemical disinfection of combined sewer overflow waters using performic acid or peracetic acids

“…Chlorine dioxide is used in installations for CSO disinfection in the USA. The disadvantages of chlorine dioxide are the higher capital cost of installation compared to chlorine (White, 1992), and the formation of the residual product, chlorite, which has a medium toxicity to aquatic organisms that requires consideration (Svecevicius et al, 2005). UV radiation and ozone are also efficient disinfection methods, but they are complex and expensive to install for treatment of CSO.…”

Algal toxicity of the alternative disinfectants performic acid (PFA), peracetic acid (PAA), chlorine dioxide (ClO 2 ) and their by-products hydrogen peroxide (H 2 O 2 ) and chlorite (ClO 2 − )

“…This species and the standard test setup was chosen as test organism to increase the regulatory relevance of the results and to ensure that they can be compared to other studies in future. At present, only few studies report the ecotoxicity of PAA, PFA, hydrogen peroxide, ClO 2 and chlorite and there is no consistent information regarding toxic effect of disinfected effluents (Antonelli et al, 2009;Liu et al, 2015;Meinertz et al, 2008;Svecevicius et al, 2005). Ecotoxicity data of disinfectants are important as input to environmental risk assessments of possible disinfection systems using these chemicals and eventually to obtain permit from the authorities for their use in this application.…”

“…1B by oxidizing bacteria and other matter in the treated water thus forming chlorite as a significant by-product of the treatment (Korn et al, 2002;Lee et al, 2004;Svecevicius et al, 2005):…”

Treatment of Arctic wastewater by chemical coagulation, UV and peracetic acid disinfection

“…An ideal disinfectant should efficiently remove maximum pathogenic microorganisms without generating toxic and undesirable by-products and it should be inexpensive and technologically compatible (Tchobanoglous et al, 2003). Hypochlorite and chlorine dioxide are well known disinfectants used in the water industries (White, 2010), which could be used to reduce contamination by microorganisms from wastewater, but the by-products of these are of environmental concern (Bayo et al, 2009;Hrudey and Charrois, 2012;Nurizzo et al, 2005;Svecevicius et al, 2005;Watson et al, 2012). Ozone is a very efficient disinfectant; however, the sophisticated technology to generate ozone makes it unsuitable for disinfection of wastewater in the Arctic region.…”

“…Furthermore, it shows high effectiveness in reducing bacterial resistance to chemical disinfection. UV disinfection does not produce toxic by-products compared to chemical disinfectants such as chlorine and chlorine dioxide (Svecevicius et al, 2005;USEPA, 1999;White, 2010). The effectiveness of a UV disinfection system depends on the characteristics of the wastewater, the intensity of UV radiation, the amount of time the microorganisms are exposed to the radiation, and the reactor configuration (USEPA, 1999).…”