Arsenic (As) is well known to be a toxic element (WHO 2003) and has also been classified as one of the carcinogenic chemical elements by the International Agency for Research on Cancer (IRAC) (Tchounwou et al. 2004). Exposure of the human body to arsenic through drinking water has been reported from many countries (Bhattacharya et al. 2007) such as Argentina (Bundschuh et al. 2004), Bangladesh (Watanabe 2001), China, India (Roychowdhury et al. 2005), Nepal, Vietnam (Berg et al. 2001), and Japan (Kondo et al. 1999), where large areas of groundwater are contaminated by As with concentrations ranging from 0.1 to over 2 mg L−1 (Mandal and Suzuki 2002, Smedley and Kinniburgh 2002). These concentrations are higher than 0.01 mg L−1, a standard recommended by the World Health Organization (WHO) (WHO 2006). Long-term consumption of drinking water contaminated with As causes, among other diseases, cancers of the skin, lung, liver, kidney and bladder (Liao et al. 2009). Thus, the As contamination in groundwater is considered a serious problem.