Arsenic in Drinking Water—A Global Environmental Problem

Abstract

Arsenic contamination of groundwater is a global environmental problem affecting a large number of populations, especially in developing countries. The "blackfoot disease"that occurred in Taiwan more than half of a century ago was attributed to drinking arsenic-contaminated water from deep wells containing high concentrations of the trivalent arsenite species. Similar arsenic poisoning cases were reported later in Chinese Inner Mongolia, Bangladesh, and India—all related to drinking groundwater contaminated with arsenic. The maximum contaminant level (MCL) of arsenic in drinking water has been changed recently by the U.S. EPA from 50 ppb to 10 ppb; the compliance date is January 2006. This article summarizes documented global arsenic contamination problems, the regulatory controversy regarding MCL of arsenic in drinking water, and available technologies for removing arsenic from contaminated waters. Methods for analyzing total arsenic and arsenic species in water are also described.

Arsenite removal from water by electro-coagulation on zinc–zinc and copper–copper electrodes

“…As(III) and As(V), which are called as arsenite and arsenate, respectively. Arsenite is more toxic due to its affinity for thiols group of proteins to form products that cause body malfunctions (Wang and Wai 2004). It has also been observed that arsenite and arsenate are found in anaerobic (highly reducing conditions) and oxygenated water, respectively (Gomes et al 2010).…”

Adsorption of arsenate and arsenite on titanium dioxide suspensions

“…Arsenic [arsenite (As(III)) and arsenate (As(V))] contamination in groundwater has become a major concern in many countries including Bangladesh, Vietnam, and the western United States [1]. The main source of arsenic is geological, but human activities such as mining and pesticides can also cause arsenic pollution.…”

“…Under groundwater conditions, As(III) is the predominate form of arsenic, which is more toxic and mobile than As(V) [1]. As(III) has low affinity with mineral surfaces while As(V) adsorbs easily to solid surfaces.…”

PEI modified Leucaena leucocephala seed powder, a potential biosorbent for the decontamination of arsenic species from water bodies: bioremediation

“…Contaminated drinking water has been found in Argentina, Chile, Mexico, China, India, Hungary, Bangladesh and Vietnam. Of these regions, India and Bangladesh are most seriously affected in terms of the size of the population at risk and the magnitude of the health problems (Wang and Wai 2004;Sohel et al 2009). Approximately 30-35 million people in Bangladesh and 7 million people in West Bengal (India) are exposed to elevated levels of arsenic in drinking water.…”