Total organic carbon drinking water

Water for injection (WFI) is the most widely used solvent for parenteral preparations. The USP requirements for WFI and purified water have been recently updated to replace the traditional wet and colorimetric analytical methods with the more modern and cost-effective methods of conductivity and total organic carbon. Water for injection must be prepared and stored in a manner to ensure purity and freedom from pyrogens. The most common means of obtaining WFI is by the distillation of deionized water. This is the only method of preparation permitted by the European Pharmacopoeia (EP). In contrast, the USP and the Japanese Pharmacopeias also permit reverse osmosis to be used. The USP has also recently broadened its definition of source water to include not only the U.S. Environmental Protection Agency National Primary Drinking Water Standards, but also comparable regulations of the European Union or Japan. 

A review committee set up under the auspices of the North Atlantic Treaty Organization in 1979 listed 744 chemical contaminants that had been identified in the drinking water of 14 countries (I). Since then, more have been found. However, it has been estimated that more than 80 of the total organic carbon in the drinking water still remains uncharacterized. This growing number of organic chemicals identified in drinking water supplies led to public concern and debate about the potential risks to health. 

This paper will consider the efficacy or horse-radish peroxidase (HPR) for the removal of 2-chlorophenol — a taste and odor compound, and pentachlorophenol — a wood preservative sometimes found as a contaminant in drinking-water. These compounds were evaluated at low as well as high concentrations, and in the presence of potential competing compounds. Competing compounds may be innocuous aromatic compounds or other specific micro pollutants. Humic substances are organic compounds composed mainly of aromatic structures [ 14 ] which account for up to 90% of the background total organic carbon (TOC) in natural waters [15 ]. Recent studies have indicated th t the presence of humic acids may deactivate horse-radish peroxidase [16 ]. 

Potable Water Treatment. Treatment of drinking water accounts for about 24% of the total activated carbon used in Hquid-phase apphcations (74). Rivers, lakes, and groundwater from weUs, the most common drinking water sources, are often contaminated with bacteria, vimses, natural vegetation decay products, halogenated materials, and volatile organic compounds. Normal water disinfection and filtration treatment steps remove or destroy the bulk of these materials (75). However, treatment by activated carbon is an important additional step in many plants to remove toxic and other organic materials (76—78) for safety and palatability. 

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