Geo-Analyst , ISSN 2249-2909 July, 2016 Spatial variation of fluoride contamination: A field study on the fluoride affected villages of Birbhum district (W.B, India) Priyabrata Mondal* Abstract Fluoride compound (F ̄) is necessary for a certain content to eradicate the dental caries and to strengthen the bones. Fluoride remains in a certain amount in water. According to World Health Organization (WHO, 2002) the normal level of fluoride in underground water is 1.5 mg/L and according to Bureau of Indian Standard (BIS, 2009) the normal level of fluoride in underground water is 1 mg/L. Crossing this limit (1.5 mg/L) fluoride contaminates the water. If the same water is used mainly for drinking purpose then health hazard may occur. This health hazard is known as fluorosis. Person once attacked by this is never cured fully from this. Patients lost their ability to do work. Different districts of West Bengal are suffering from the fluorosis in one or different ways (dental, skeletal and non-skeletal). Birbhum district of West Bengal is one of them. The western part of this district has been affected severely by fluoride contamination in ground water. Consequently, the health of people of study villages has been deteriorated due to fluorosis. Thus their working ability has decreased miserably. But they need to do work for income generation to feed their family members. At the same time people of this region are belonging to the poverty stricken society. In such condition depression in economy is increasing day by day which is again solidifying the base of poverty. If this condition continues then the eastern part of Birbhum District will grow economically with the passage of time and western part will be economically more backward. That’s why Birbhum District has been chosen for the purpose of study and in this paper an attempt has been made to elaborate the spatial pattern of fluoride contamination in this district. Keywords: Fluoride contamination, underground water, spatial pattern, geology Introduction There are seven blocks of Birbhum District (Map: 1) affected by the problem of fluoride. Those are Nalhati-I, Rampurhat-I, Mayureswar-I, Sainthia, Suri-II, Rajnagar and Khoyrasole. Nalhati-I, Rampurhat-I and Khoyrasole are three blocks where our study villages exist. “The Nasipur is the first place to report cases of fluorosis in West Bengal. The village is located in Nalhati Block-I of Birbhum district” (Chatterjee, 2004). According to B.M.O.H of Rampurhat-I block, problem of fluoride has come out in Rampurhat-I block during the first half of 1980’s (most probably 1984). However many villages of Birbhum district were found to have the same problem. Most of them belong to the western side of Birbhum district. *Research Scholar, Department of Geography Visva-Bharati 54 Geo-Analyst , ISSN 2249-2909 July, 2016 Map: 1 Location of the study area Birbhum district is situated in between 23°32 ʹ30 ʺ and 24°35 ʹ00 ʺ north latitude and 88°01 ʹ40 ʺ and 87°05 ʹ25 ʺ east longitude. In shape it looks like a triangle. Birbhum is bounded by Murshidabad District on east and Burdwan District on south and Bihar (state) on the west. Seven blocks of Birbhum District have been affected. Five villages have been selected as sample villages for the purpose of study. Those villages are Nasipur (Nalhati-I CD-Block), Bhabanandapur (Nalhati-I CD-Block), Nawapara-Junidpur (Rampurhat-I CD-Block), Fullachak (Khoyrasole CD-Block), Lauberia (Khoyrasole CD-Block) (Map: 2). 55 Geo-Analyst , ISSN 2249-2909 July, 2016 Map: 2 Discussion Pattern of fluoride contamination in Birbhum District Though, only 0.93 % tube wells of Birbhum District are contaminated by fluoride but in West Bengal, spot with maximum fluoride content is found in Birbhum District. That is 20.40 mg/l (Diagram: 1 and 2). 56 Geo-Analyst , ISSN 2249-2909 July, 201 6 Diagram: 1 Diagram: 2 Nalhati-I, Rampurhat-I and Khoyrasole are found as top three blocks if we rank different blocks of Birbhum District according to the highest fluoride content. Sample villages have been chosen from these three blocks (Diagram: 3). 57 Geo-Analyst , ISSN 2249-2909 July, 201 6 Diagram: 3 Table-1: Maximum fluoride content (mg/l) in different GP of Nalhati-I Block GP of Nalhati-I Block Maximum Fluoride content (mg/l) Banior 0.71 Barla 0.54 Bautia 0.82 Haridaspur 20.4 Kaitha-I 1.72 Kaitha-II 0.66 Kalitha 1.65 Kurumgram 0.48 Nalhati - a 0.63 Nalhati - b 0.16 Paikpara 0.78 Source: PHED, West Bengal, 2006 There are five study villages. Those villages belong to Nalhati -I, Rampurhat-I, and Khoyrasole blocks. Nalhati-I block has 11 gram panchayat (GP). Fluoride level in underground water of each panchayat has been shown in the table where Haridaspur panchayat records with the highest level within the block (Table: 1). Nasipur and Bhabanandapur are two study villages lying in that GP. 58 Geo-Analyst , ISSN 2249-2909 July, 2016 Beside this there are two other GP namely Kaitha-I and Kalitha where level of fluoride is above the permissible limit. On the other hand Rampurhat-I block has 9 GP of which Narayanpur and Kharun panchayat are with first and second highest level of fluoride respectively (Table: 2). Nawapara-Junidpur study village belongs to the Kharun GP. Kusumba and Mashra are two other GP where fluoride level in underground water is above the permissible limit.Here this village has been selected for the purpose of study because this is the worst affected than any other villages of Narayanpur Panchayat. Table-2:Maximum fluoride content (mg/l) in different GP of Rampurhat-I Block GP of Rampurhat-I Block Maximum Fluoride content (mg/l) Ayas 0.65 Barshal 0.79 Bonhat 1.39 Dakhalbati 0.53 Kasthagora 0.67 Kharun 11.1 Kusumba 2.84 Mashra 3.77 Narayanpur 16.2 Source: PHED, West Bengal, 2006 Similarly, Khoyrasole block has 10 GP of which 4 GP namely Kendgore, Hazaratpur, Khoyrasole and Nokraconda are with fluoride level above the permissible limit. Kendgore GP has the highest level of fluoride (Table: 3). Fullachak village is belonging to this GP. Fifth study village Lauberia is located at Khoyrasole block. Maximum fluoride content in different study villages have been shown in the map (Map: 3). 59 Geo-Analyst , ISSN 2249-2909 July, 2016 Table-3: Maximum fluoride content (mg/l) in different GP of Khoyrasole-I Block GP of Khoyrasole Block Maximum Fluoride content (mg/l) Babuijore 0.78 Barra 1.3 Hazaratpur 3.12 Kendgore 14.1 Khoyrasole 2.81 Lokepur 0.66 Nakraconda 1.59 Panchra 0.67 Parsundi 1.14 Rupaspur 0.81 Source: PHED, West Bengal, 2006 Map: 3 60 Geo-Analyst , ISSN 2249-2909 July, 2016 Pattern of fluoride contamination in different villages a) Pattern of fluoride contamination in Nasipur village When the news of Nasipur regarding fluorosis spread all over the West Bengal then all the tube wells and wells were sealed and tap water as an alternative supply was started to be provided to the villagers of Nasipur. But already the entire village has been affected by fluorosis. However, the tap supply becomes discontinuous because of many reasons e.g. loadshedding of electricity or low voltage. At that time they drink the water of unfilled stone mine. Beside this, the villagers near the water of unfilled stone mine drink that water most of the time. Similarly the differentsorts of mine workers working at the mine usually drink the same water. Tap service is provided at particular time of each day. Many poor villagers miss to collect or store the tap water at the right time. Entire region is characterised by basalt rock at the surface. Basalt rock is one of the most efficient sources of fluoride. The wall of the unfilled stone mine is also basalt. That’s why the water of that unfilled stone mine is also contaminated by fluoride as stated by laboratory attendant of CMOH, Suri. From the field study we have known that recently 90 % surveyed households of Nasipur are drinking water from tap, unfilled stone mine, tube wells and wells. Only 10 % are drinking water only from tap . b) Pattern of fluoride contamination inBhabanandapur village This village is located at Haridaspur panchayat where Nasipur village lies. The scenario of this village is almost similar to Nasipur village. When fluoride was detected in underground water of Bhabanandapur, then all the government tube wells and wells were sealed. At the place of tube wells and wells, tap water was started to be supplied. But the villagers drink from alternative source when tap service is halted. Tap service is provided at particular time of each day. Many poor villagers miss to collect or store the tap water at the right time. Beside this if electric load shading occurs then water is not provided. Most of the households have the own tube well or well in their house for alternative use. None of them are tested in the laboratory for checking the level of fluoride. So, there is a large probability of having fluoride in that water because all the tube wells whether that is private or government have already been banned as they are from the same source. From the field study we have known that recently 8 % surveyed households of Bhabanandapur are drinking water from tap, tube wells and wells. 92 % households are drinking water only from tap. c) Pattern of fluoride contamination in Nawapara-Junidpur village The Nawapara-Junidpur village is located at the right bank of Dwarka River.