Journal of Hazardous Materials B137 (2006) 464–479 Laboratory based approaches for arsenic remediation from contaminated water: Recent developments P. Mondal, C.B. Majumder ∗ , B. Mohanty Department of Chemical Engineering, Indian Institute of Technology Roorkee, Roorkee 247667, Uttranchal, India Received 8 April 2005; received in revised form 13 February 2006; accepted 16 February 2006 Available online 28 February 2006 Abstract Arsenic contamination in water has posed severe health problems around the world. In spite of the availability of some conventional techniques for arsenic removal from contaminated water, development of new laboratory based techniques along with enhancement and cost reduction of conventional techniques are essential for the benefit of common people. This paper provides an overview of the arsenic issue in water such as modes of contamination of ground water as well as surface water by arsenic, its metabolism and health impacts, factors influencing arsenic poisoning, fundamentals of arsenic poisoning mechanism and world scenario of arsenic poisoning. It discusses and compares the conventional laboratory based techniques, like precipitation with alum, iron, Fe/Mn, lime softening, reverse osmosis, electro dialysis, ion exchanges, adsorption on activated alumina/carbon, etc., for arsenic removal from contaminated water. It also discusses the best available techniques and mentions the cost comparison among these techniques too. Recent developments in the research on the laboratory based arsenic removal techniques, like improvement of conventional techniques and advances in removal technology along with its scopes and limitations have also been reviewed. © 2006 Elsevier B.V. All rights reserved. Keywords: Arsenic mobilization; Poisoning effects; Surface coated adsorbents; Advanced technique; Bio-filtration 1. Introduction Arsenic, the world’s most hazardous chemical [1], is found to exist within the shallow zones of ground water of many countries like Argentina, Bangladesh, India, Pakistan, Mexico, Mongo- lia, Germany, Thailand, China, Chile, USA, Canada, Hungary, Romania, Vietnam, Nepal, Myanmar, Cambodia, etc. in various concentrations [2–19]. In some places in Bangladesh its con- centration is as high as 1000 g/l [4]. The contaminants like iron, calcium, magnesium, bicarbonate, chloride and sulfate are found to be associated with arsenic in the ground water of these countries. Surface water is also found to be contaminated with arsenic by the anthropogenic sources to various degrees. White et al. reported that the NaCl-dominated brine of Tisak¨ urt, Hun- gary, contains more than 5800 g/l of arsenic [20]. Considering the lethal impact of arsenic on human health, environmental authorities have taken a more stringent attitude ∗ Corresponding author. Tel.: +91 1332 270492; fax: +91 1332 276535. E-mail address: chandfch@iitr.ernet.in (C.B. Majumder). towards the presence of arsenic in water. World Health Organiza- tion (WHO) in 1993 and National Health and Medical Research Committee (NHMRC), Australia, in 1996 had recommended maximum contaminant level (MCL) of arsenic in drinking water as 10 and 7 g/l respectively [21,22]. The MCL of arsenic in drinking water has also been reduced from 50 to 10 g/l by European Commission in 2003 [23]. Environmental Protection Agency (EPA), USA, has decided to move forward in imple- menting the same MCL of arsenic that is recommended by WHO for drinking water in 1993 [24]. Japan and Canada has reduced the MCL for arsenic in drink- ing water to 10 and 25 g/l, respectively. The MCL for arsenic in countries like India, Bangladesh, Taiwan, China, Vietnam, etc. is also 50 g/l [25]. Water is one of the most important media through which arsenic enters into the human body. As the diagnosis and med- ication of the arsenic related diseases are difficult the treatment of contaminated water as a preventive measure appears to be an effective alternative to combat arsenic poisoning. Arsenic may be available in water in variable oxidation states (+5, +3, 0, -3) [26,27]. From contaminated water it can be converted into 0304-3894/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.jhazmat.2006.02.023