Sodium chlorate

Endpoint summary

Additional information

A representative average upon delivery of industrial hypochlorite to bleach formulators is 3 to 5 g/L sodium chlorate in commercial concentrated (15% w/w) hypochlorite product. The initial level in domestic bleach is 0.95 g/L. Taking into consideration that the degradation of hypochlorite to chlorate is 20% per year at 20 °C and the average shelf life of domestic bleach is three months, the total chlorate level amounts to 1.8 g/L in domestic bleach. The predicted environmental input of chlorate from bleach in surface waters is 12.5 µg/l (range 0.4 - 30 µg/l) for(FIFE-AIS (1995)). In theaverage chlorate levels in surface water vary from less than 3 µg/l to 45 µg/l (Versteegh,et al. (1993)). More recent data are available for the riverin The Netherlands (RIWA (2001-2002)). Close to Nieuwersluis the chlorate concentration in 2001 was on average 5.17 µg/l. In 2002 the average concentration was 5.4 µg/l. There are few data on chlorate levels in brackish or marine waters. In the mid-1980s in the, mean values of up to 53 mg ClO₃-/L were recorded in kraft pulp mill effluent discharged into coastal waters (Rosemarinet al.(1994)). This data is mentioned even though it can not be evaluated because it was cited in a publication. Landeret al.(1994) gives chlorate levels in the Baltic Sea measured after 1987 caused by the same paper mill as mentioned by Rosemarinet al.(1994). In 1987 new technologies for removing chlorate were implemented in this paper mill. Because of this improvement the chlorate concentration in the effluent of the mill decreased drastically to less than 2 mg ClO₃-/l and at a distance of 3 to 4 km from the diffuser the concentration was less than 2 µg ClO₃-/l.