Evaluation of bromate ions level introduced by sodium hypochlorite during post-disinfection of drinking water.

During the last ten years, interest concerning the occurrence of bromate in drinking water has grown due to its potential carcinogenicity and the new regulations. One source of bromate in finished water is due to its presence in the sodium hypochlorite solutions used for the disinfection of water. In fact, the brine solutions used for the production of sodium hypochlorite contain bromide ions in varying degrees that subsequently generate a certain quantity of bromate ions. Bromate concentrations ranging from 82 to 857 mg l(-1) (0.5-7.4 mg BrO3-/ g Cl2) have been found in commercial solutions of sodium hypochlorite used by Société Anonyme Gestion des Eaux de Paris (SAGEP), a company that produces drinking water for Paris, France. In addition, the chlorine concentration of the hypochlorite solution can decrease during storage, consequently the added amount of bromate increases for a given applied dose of chlorine.

Determination of chlorinated pesticides in water by SPME/GC.

Solid-phase microextraction (SPME) followed by gas chromatography (GC) coupled with an electron capture detector has been applied for the analysis of chlorinated pesticides in water. Molecule adsorption on 100 microm polydimethylsiloxane (PDMS) fibers was activated by immersion of the whole fiber-sample system in an ultrasonic bath. The good reproducibility, low detection limits and wide linear ranges obtained encourage the use of this technique in water control.