International Journal of Scientific & Engineering Research, Volume 5, Issue 5, May-2014 796 ISSN 2229-5518 IJSER © 2014 http://www.ijser.org Arsenic Contamination of Tube Well Water in Chittagong City, Bangladesh- A Case Study M.A. Malek 1 , M.N. Uddin 2 , M. Atiquzzaman 3 , A.H.M.G. Hyder 4 , S.K. Palit 5 Abstract— Arsenic, a semi-metal, colourless, tasteless and odourless toxic element, is known as the “King of Poison” at present. Arsenicosis is a well-known chronic disease which occurs due to drinking of arsenic contaminated tube well water having arsenic level exceeding the nor- mal level for a prolonged period. It is likely to create a significant health impact ranging from skin lesions to cancer culminating in death. In 2008, Chittagong University of Engineering and Technology (CUET) and the Institution of Engineers Bangladesh, Chittagong Centre (IEBC) have been jointly conducted a sample survey in 41 Wards, administrative sub-divisions, of the Chittagong city in Bangladesh. From the re- search, arsenic has been found in shallow tube well water in 13 city wards which exceeds WHO guideline value of 0.01 mg/l for drinking water. In the present work, South Bakalia-a city ward in Chittagong has been taken as the study area for detailed investigation where arsenic concentration was found as 0.3 mg/l to 0.4 mg/l in sample survey. All the tube wells of the ward were tested for measuring arsenic concentra- tion in the field by collecting water sample from tube wells using Wagtech Arsenic Field Test Kit (UK). Arsenic contaminated tube-wells have been marked with red colour paint for future reference and to create public awareness. A total number of 45 deep tube well’s water were also tested randomly throughout the ward and found free from arsenic. Arsenic contamination has been found only in shallow tube wells and clus- tered in particular areas. Considering the result, arsenic contaminated prone areas within the ward have been identified so that people of the area consume water for drinking purpose from alternate sources. Index Terms—Arsenic, Arsenicosis, Contamination, Shallow tube-well, Deep tube-well, Public awareness, Arsenic prone area, Chittagong city. ——————————  —————————— 1 INTRODUCTION 1.1 Background angladesh is facing perhaps the largest mass poisoning regard- ing arsenic in history. Though the shallow tube wells are free from pathogens but most of the shallow tube well’s water in Bangla- desh is found to be contaminated with arsenic. Once these tube wells were lauded for saving lives by preventing or reducing the intensity of water borne diseases but at present these tube wells are expected to be responsible for a slow and painful death of lives for providing arsenic contaminated drinking water [1] . British Geological Survey(BGS) and Department of Public Health Engineering (DPHE), Bangladesh conducted a national hydro- chemical survey of well water in Bangladesh in the year 1998 and 1999 and found alarming amount of arsenic contamination in ground water of Bangladesh [2] . Considering the Bangladesh standard limit of arsenic in drinking water (0.05 mg/l), about 27% of all shallow tube wells installed in 61 plain districts of Bangladesh could be remarked as contaminated with arsenic. The Corresponding figures for deep tube wells sunk to a depth of 150 meters and above, were 5% and 1% for arsenic contamination of 0.01 mg/l and 0.05 mg/l, respective- ly. It is widely believed that Bangladeshi peoples are getting expo- sure to arsenic because of the extensive use of arsenic contaminated groundwater for drinking and irrigation purposes since the 1960s [2] . But the two major cities in Bangladesh such as Chittagong were not covered by the survey, though groundwater is extensively used in these cities [2] . Consequently, in 2008, Chittagong University of Engineering & Technology (CUET) and the Institution of Engineers Bangladesh, Chittagong Centre (IEBC) jointly conducted a samples survey in Chittagong City Corporation (CCC) area where 41 num- bers of ward (administrative sub-divisions) are located. Arsenic contamination is due to natural geological setting caused by Holocene sea level rise and Ganga-Brahmaputra deltaic sedimenta- tion [3] . The mobility of arsenic from the sedimentary pyrite layer into the aquifers due to large-scale withdrawal of groundwater for agriculture and drinking purposes is due to the green revolution and outbreak of cholera in the 1960s in South Bengal. This followed rapid intake of O 2 (oxygen) within the pore spaces of the sediments and are believed to be due to the following geochemical processes: FeS 2 +2H 2 O+5O 2 = FeSO 4 +2H 2 SO 4 …… (1) 4FeSO 4 +O 2 +2H 2 SO 4 =2Fe(SO 4 ) 3 +2H 2 O …….. (2) FeS 2 + 7Fe 2 (SO 4 ) 3 + 8H 2 O = 15 FeSO 4 + 8H 2 SO 4 ……. (3) Prof. Khalilur Rahman, Chemical Engineering Department, BUET, Bangladesh (1992) reveals: a much serious problem is the disposal of highly toxic waste sludge from HFFG that has accumulated in the factory from carbon dioxide absorption tower. It was estimated that well over 22000 CFT of packing material along with sludge contain- ing arsenic has piled up. The arsenic control in the sludge is about 40%. The process has since been modified and arsenic is not used in the absorbing solution, but large quantity of solid material remains dumped in concrete pit and in the open area. B ______________________________________________ • Lecturer, Department of Civil Engineering, World University of Bangladesh, Dhaka, Bangladesh, E-mail: amalek.ce@gmail.com • Ex Student, Department of Civil Engineering, Chittagong Univer- sity of Engineering & Technology, Bangladesh, E-mail: nymebd@gmail.com • Lecturer, Department of Civil Engineering, World University of Bangladesh, Dhaka, Bangladesh, E-mail: atique_kuet@yahoo.com • Lecturer, Department of Civil Engineering, World University of Bangladesh, Dhaka, Bangladesh, E-mail: 82hyder@gmail.com • Professor, Department of Civil Engineering, Chittagong Universi- ty of Engineering & Technology, Bangladesh, E-mail: k bd@ t bd IJSER