The Pros And Cons Of Drinking Water Contamination

Water is very important to protract civilization (Gleick, 1998; Vitousek et al., 1997), but with a rising global human population, and alteration in weather types as a result of climate change, there are extending concerns and issues with quality and quantity of water for human use. The major topic of concerns is increasing incidences of microbial and chemical pollution in water (Schwarzenbach, et al., 2010; Vorosmarty et al., 2000). This becomes a serious health hazard if the drinking water is contaminated by any types of contaminant. The bacterial contamination is the most numerous type of contamination present in drinking water. This contaminated drinking water can cause gastro-intestinal illness. Mainly fecal indicator bacteria are chosen

It is able to inactivate most of the bacteria efficiently and enteric viruses (WHO 2006). But, free chlorine is ineffective in inactivating waterborne pathogens such as C. parvum and Mycobacterium avium, the latter is the reason for the biofilm production within water distribution system (Shannon, Bohn et al. 2008). Another main disadvantage of free chlorine is the formation of its disinfection by-products (DBPs), organohalides, especially trihalomethanes (THMs) in chlorinated drinking water which are potentially mutagenic and carcinogenic to human health (Yang and Cheng 2007; Lu, Zhang et al. 2009). Chlorine dioxide is another option for disinfection processes instead of free chlorine. Due to the strong oxidation property of chlorine dioxide, it has been used for disinfection process to destroy most of the pathogens. But, chlorine dioxide does not react with natural organic matter to form THM. However, other DBPs such as un-reacted chlorite ions and chlorate ions may have probable adverse health effects (Aranda-Rodriguez, Koudjonou et al. 2008). Chloramine is commonly used as a secondary disinfectant in municipal water distribution systems as an alternative to free chlorine. But, chloramine is a weak disinfectant against viruses and cysts. Besides, adding chloramines to the water may increase health risks to human (Miranda, Kim et al. 2007). Chloramination is associated with the formation of nitrosamines (commonly detected as N-nitrosodimethylamine (NDMA)), which are emerging by-products of health and regulatory concern (Mitch, Sharp et al.