Arsenic (As) is a semi-metal element with a name that originated from the Greek word arsenikon, which means mighty. It is a natural element found in the Earth's crust. The contamination of ground and surface water with As commonly occurs when water flows through As-rich rock. The contamination of ground water used for drinking with As is a serious global concern. Several locations on Earth, such as Bangladesh, India, Taiwan, Great Britain, Thailand, and within the US (including Hawaii, California, and New Hampshire), have reported environmental water contamination with