Arsenic Contamination in West Bengal: Its Present & Future

International Journal of Scientific Research and Engineering Development-– Volume 3 Issue 2, Mar-Apr 2020 Available at www.ijsred.com RESEARCH ARTICLE OPEN ACCESS Arsenic Contamination in West Bengal: Its Present & Future

Koustav Dutta*, Dr. Malay Kanti Ghosh** *Student (UG), Dept. of Civil Engineering, Purulia Government Engineering College, West Bengal, India [email protected] ** Associate Professor, Dept. of Civil Engineering, Purulia Government Engineering College, West Bengal, India [email protected]

------************************ ------Abstract: Arsenic contamination in ground water and related health hazards have become a matter of serious concern in many countries of the world. A number of large aquifers in the world have been identified with problems of high levels of Arsenic concentration in ground water. Arsenic contamination in ground water of West Bengal in the range of 0.001-3.20 mg/l occurs in isolated patches, predominantly spreading over the 79 blocks in eight districts of the state. Apart from these, newer locations spreading over a few blocks of the North Bengal districts have also tested positive for the presence of Arsenic more recently. At present about 162.6 lakh people (35.48% of the total population of the State) occupying 17533 habitats live in the risk zone of potential threat in terms of Arsenic related diseases in the future. Central Ground Water Board and the Government of West Bengal have made successful endeavours to provide arsenic free drinking water to the entire population in the arsenic infested area. Arsenic free deeper aquifers have been explored by CGWB .Three aquifer systems have been identified within 100 mbgl, 120 – 160 mbgl and 200 –250 mbgl. The top aquifer within 100 mbgl is mostly arseniferous, whereas both the deeper aquifers which are separated by a thick clay (>10 m) from the overlying aquifers, capable of yielding 5 to 20 metric liters of water per second, are arsenic free. The paper thoroughly discusses the present day scenario of Arsenic concentration in the various blocks of the state of West Bengal and also emphasizes for the adoption of suitable advance techniques for dilution of Arsenic concentration in groundwater to move ahead by a step in the eradication of the lethal element Arsenic from the groundwater. Keywords — Arsenic contamination in West Bengal, Combating the arsenic crisis, Population at risk, Sub-surface geology ------************************ ------contamination. Apart from the aforementioned

I. INTRODUCTION districts, more recent studies have revealed the The occurrence of Arsenic in ground water was first presence of Arsenic at significant levels in the reported in 1980 in West Bengal in India. In West groundwater in the various districts of North Bengal Bengal, 79 blocks in 8 districts have Arsenic like Coochbehar, Dinajpur (N) and Dinajpur (S). beyond the permissible limit of 0.05 mg/l. The most affected areas are on the eastern side of Bhagirathi Excessive intake of arsenic in human body causes River in the districts of Malda, Murshidabad, health hazards that are manifested in the form of Nadia, 24 Parganas (N) and 24 Parganas (S) and arsenic poisoning. The main source of poisoning is also on the western side of the river spreading over through drinking water. The limit of Arsenic in the districts of Howrah, Hooghly and Burdwan (E drinking water standard as per BIS (Bureau Of & W). The occurrence of Arsenic in ground water Indian Standards) is 0.01 mg/L. (IS 10500 -1993 is mainly in the aquifers up to 100 m depth. The Amended 2003). However affected West Bengal deeper aquifers are free from Arsenic

ISSN : 2581-7175 ©IJSRED: All Rights are Reserved Page 659 International Journal of Scientific Research and Engineering Development-– Volume 3 Issue 2, Mar-Apr 2020 Available at www.ijsred.com State follows the earlier standard as per BIS (1993) Methodology: of maximum permissible value 0.05 mg/L (for The various informations collected has been detection) and 0.01 mg/L (for removal). There is no presented in a systematic way in the form of charts, immediate effect on the health of the consumer, if maps and other tools of statistics to get a detailed small doses are consumed. But due to slow insight into the matter to ultimately discuss accumulation of arsenic from continuous or thoroughly the effective measures against the repeated exposures, various symptoms may appear problem of Arsenic contamination in groundwater in the body of the consumer. Both, geogenic towards the end of the study. (natural) and anthropogenic sources of arsenic contribute to the enrichment of the element in groundwater.

At present the contamination has been predominantly found in the eight districts of West Bengal as tabulated below:

Table 1: Arsenic affected districts of West Bengal

Districts Arsenic Level in groundwater in mg/l

Hooghly, Howrah, Coochbehar, Malda, Murshidabad, Nadia, 24 0.01-0.05 Parganas (N), and 24 parganas (S)

Hooghly, Malda, Murshidabad, Nadia, 24 Parganas (N), and 24 >0.05 parganas (S)

II. MATERIALS & METHODOLOGY Fig. 1 : Map of West Bengal Study Area: The entire study has been restricted to the various III. RESULTS & DISCUSSIONS districts of the state of West Bengal at the block

level. The region selected is small so as to The level of Arsenic detected in the various understand the condition of the groundwater of the locations within a particular affected block has been particular region in a great detail and interpret its obtained and the location at which the groundwater condition in the near future with better accuracy. has the maximum level of Arsenic in it only has

been considered to be the maximum level of Data Source: Arsenic present in that block. All the data and informations used in the study are

based on the various reports and publications of The contamination situations in the various Arsenic Central Ground Water Board (CGWB) published affected districts are hereby discussed one by one in from time to time. details:

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Table 1: Details of Arsenic Level in Groundwater for the Table 4: Details of Arsenic Level in Groundwater for the affected Blocks of Burdwan (E & W) District affected Blocks of Howrah District Block Location Arsenic Level in Block Location Arsenic Level in groundwater in mg/l groundwater in mg/l

Arsenic Level in groundwater 0.01 – 0.05 mg/l Arsenic Level in groundwater 0.01 – 0.05 mg/l

Purbasthali I Hematpur 0.03 Domjur Ramrajatala 0.01 Purbasthali II Chatani 0.05 Arsenic Level in groundwater > 0.05 mg/l Arsenic Level in groundwater > 0.05 mg/l ------

‹ Malda

‹ Coochbehar Table 5: Details of Arsenic Level in Groundwater for the Table 2: Details of Arsenic Level in Groundwater for the affected Blocks of Malda District affected Blocks of Coochbehar District Block Location Arsenic Level in Block Location Arsenic Level in groundwater in groundwater in mg/l mg/l

Arsenic Level in groundwater 0.01 – 0.05 mg/l Arsenic Level in groundwater 0.01 – 0.05 mg/l

Haldibari Dhaprahat 0.04 English Bazar Phulbaria 0.03 Harishchandrapur I Tulsihata 0.02 Arsenic Level in groundwater > 0.05 mg/l Kaliachak I Nauda 0.04 Kaliachak I I Muthabari 0.05 ------Kaliachak I II Krishnapur 0.03 Manikchak Mathurapur 0.05 Old Malda Malda 0.02 ‹ Hooghly Ratua I Bhaluka 0.02 Ratua II Paranpur 0.04 Table 3: Details of Arsenic Level in Groundwater for the affected Blocks of Hooghly District Arsenic Level in groundwater > 0.05 mg/l Block Location Arsenic Level in groundwater in mg/l English Bazar Milky 0.15 Kaliachak I Khaschandpur 0.302 Arsenic Level in groundwater 0.01 – 0.05 mg/l Kaliachak II Raipara 0.078 Kaliachak III Jalalditola 0.115 Srirampur- Uttarpara 0.04 Manikchak Damodarpur 0.131 Uttarpara Ratua I Baharal 0.138 Balagarh Jirat 0.02 Ratua II Paranpur 0.065 Kalitala Arsenic Level in groundwater > 0.05 mg/l Gajole Ghatsol 0.082

Balagarh Milangarh 0.052

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Table 6: Details of Arsenic Level in Groundwater for the Table 7: Details of Arsenic Level in Groundwater for the affected Blocks of Murshidabad District affected Blocks of Nadia District Block Location Arsenic Level in Block Location Arsenic Level in groundwater in groundwater in mg/l mg/l

Arsenic Level in groundwater 0.01 – 0.05 mg/l Arsenic Level in groundwater 0.01 – 0.05 mg/l

Berhampur Daulatabad 0.02 Chakdah Narvtipara 0.03 Beldanga I Swarupnagar 0.04 Chapra Maharajpur 0.03 Beldanga II Debpur 0.04 Hanskhali Khamarsimulia 0.05 Bhagawangola I Bahadurpur 0.04 Haringhata Subarnapur 0.04 Bharatpur I Gangedda 0.01 Kaliganj Kaliganj 0.04 Bharatpur II Khandagram 0.02 Karimpur I Madhyagopalpur 0.05 Domkal Domkal 0.03 Karimpur II Narayanpur 0.04 Farakka Chaukigram 0.04 Krishnaganj Gede 0.02 Hariharpara Hariharpara 0.05 Krishnanagar I Bhaluka 0.05 Jalangi Sagarpara 0.01 Krishnanagar II Chowgacha 0.03 Kandi Gokarna 0.04 Nabadwip Mukundapur 0.04 Lalgola Pithtala 0.01 Nakashipara Gachha 0.05 Mur -Jiaganj Ranjitpara 0.02 Ranaghat I Birnagar 0.02 Nabagram Gurah -Pashla 0.03 Ranaghat II Cooper’s Camp 0.04 Noada Dubtala Bazar 0.02 Shantipur Kulia 0.03 Raghunathganj I Raghunathganj 0.04 Tehatta I Nazipur 0.04 Raghunathganj II Krishnaganj 0.01 Tehatta II Palasipara 0.01 Raninagar I Beikibagan 0.04 Samserganj Natun Malancha 0.05 Arsenic Level in groundwater > 0.05 mg/l Suti I Haroa 0.05 Suti II Mando More 0.04 Kaliganj Kaliganj 0.082 Karimpur I Karimpur 0.332 Arsenic Level in groundwater > 0.05 mg/l Karimpur II Nandanpur 0.184 Krishnanagar II Chowgacha 0.148 Berhampur Chhaigari 0.055 Nabadwip Jamtala 0.063 Beldanga I Farazipara 0.225 Nakashipara Chichuria 0.119 Bhagawangola II Nasipur 0.052 Ranaghat II Patuli 0.065 Bharatpur II Salinda- 0.094 Tehatta II Hanspukuria 0.076 Nabapally Domkal Bhatsala 0.265 Farakka Jorpukuria 0.186 ‹ 24 Parganas (N) Hariharpara Swaruppur 0.405 Jalangi Bhuthghari Math 0.15 Lalgola Pustampur 0.071 Table 8: Details of Arsenic Level in Groundwater for the Mur-Jiaganj Lalbagh 0.164 affected Blocks of 24 Parganas (N) District Noada Trimohini 0.058 Block Location Arsenic Level in groundwater in Raninagar I Nazipur 0.065 mg/l Samserganj Jayrampur 0.051

Khargram Khargram 0.065 Arsenic Level in groundwater 0.01 – 0.05 mg/l

Amdanga Nima 0.01

ISSN : 2581-7175 ©IJSRED: All Rights are Reserved Page 662 International Journal of Scientific Research and Engineering Development-– Volume 3 Issue 2, Mar-Apr 2020 Available at www.ijsred.com Baduria Jasaikathi 0.02 Options for Mitigation of Arsenic Menace: Bagda Helencha 0.03 Barasat II Aminpur Bazar 0.03 The hydrogeological and hydrochemical studies carried Barrackpore I Sri Durga Palli 0.01 out in the areas having arsenic rich aquifers indicates Barrackpore II Kuliagarh 0.02 that in majority of cases, arsenic contamination owes its Basirhat I Madhyampur 0.04 origin to geological sources. In such a scenario Deganga Deganga 0.03 mitigation in terms of controlling or regulating the Polytechnic contamination may not be feasible. Therefore, it is Gaighata Thakurnagar 0.04 necessary to resort either to alternative source or to Habra I Berghoom 0.04 Habra II Balisa 0.02 adopt suitable technological options, available for Haroa Paschim Gorberia 0.04 supplying arsenic free water in the contaminated areas. Hasnabad Rajapur 0.04 The options available can broadly be grouped as under:

Hingalganj Sandal Bill 0.02 V Using Surface water sources, Rajarhat Jatragachi 0.03 V Exploring and harnessing alternative arsenic Bagdah Helencha P.S. 0.05 free aquifer, if available, Bongaon Gopalnagar 0.05 V Removal of Arsenic from ground water using Arsenic treatment plants/filters, and, Arsenic Level in groundwater > 0.05 mg/l V Rain Water harvesting.

Amdanga Purba Dhania 0.059 Supply of Surface Water: Surface water based schemes Bagda Chandanpur 0.265 are not only some of the safe options but also reduce the Barasat I Bokanda 0.089 stress on ground regime at the same time. But Barasat II Senerberia 0.143 availability of such sources is a problem and thus cannot Barrackpore II Kanchanpara 0.056 be implemented everywhere. Basirhat I Gulaichandi More 0.215 Supply of water for drinking purposes from ponds, Gaighata Gaighata P.S. 0.282 rivers etc. through pipe net work after purification by Hasnabad Rajapur 0.124 Rajarhat Jatragachi 0.761 conventional method of treatment viz. coagulation, Bongaon Gopalnagar 0.072 flocculation, rapid sand filtration and disinfections, can Swarupnagar Nirman 0.086 be considered wherever easily accessible. Horizontal roughing filter with slow sand filter can also be adopted using pond water.

Tapping Alternative Aquifer for Arsenic Free Ground ‹ 24 Parganas (S) Water: Groundwater with arsenic contamination has been found mainly in the shallow aquifers. Deep Table 9: Details of Arsenic Level in Groundwater for the aquifers when separated by thick clay layer of affected Blocks of 24 Parganas (S) District appropriate composition & thickness, sealing off the Block Location Arsenic Level in groundwater in mg/l upper arseniferous aquifer by cement, prevents percolation of arsenic contaminated ground water from Arsenic Level in groundwater 0.01 – 0.05 mg/l the top aquifer. It has been inferred from the isotopic studies carried out in West Bengal that in alluvial Bhangar I Kantatala 0.01 formations, there is no hydraulic connection between Bhangar II Kulti I 0.01 shallow and deep aquifers (belonging to different age Sonarpur Khiddaha 0.02 group) when they are separated by an appropriate Baruipur Ramnagar 0.01 impervious layer. Central Ground Water Board, while carrying out extensive work on this aspect, has Arsenic Level in groundwater > 0.05 mg/l deciphered and delineated deep arsenic free aquifers at number of places in the states of West Bengal. Deep Bishnupur II Dhopar 0.083 arsenic free aquifers, potential enough to yield adequate More water to meet the water requirement in the domestic

ISSN : 2581-7175 ©IJSRED: All Rights are Reserved Page 663 International Journal of Scientific Research and Engineering Development-– Volume 3 Issue 2, Mar-Apr 2020 Available at www.ijsred.com sector, are available in most of the arsenic affected and the use of treated arsenic contaminated water, may blocks of the state, where CGWB has carried out ground be dispensed with. Artificial recharge of rain water into water exploration. Only in the south western part of the the aquifer through recharging structures may also be district Malda, where deep aquifers (generally below 70- considered wherever hydrogeological condition is found 90 m) are constituted by hard consolidated rocks, the feasible to dilute the concentration of arsenic in ground prospect of getting arsenic free water from such water and thereby making its arsenic content within the aquifers, is yet to be explored. permissible limit. Treatment and Removal of Arsenic from ground water: While the first two options can be adopted wherever possible notwithstanding the huge financial requirement for the piped water scheme, the treatment of tube well water for removal of arsenic can also be applied in a big way, especially in the state of West Bengal. The removal of arsenic depends upon its chemical state in which it occurs in the water, viz., trivalent Arsenic (As III) and pentavalent Arsenic (As V). As (III) is much more prevalent in ground water and it is difficult to remove because it exists predominately in the non ionic form. On the other hand Arsenic (V) exists in monovalent state and when water contains iron in higher concentration, it is easier to remove As (V) as it co precipitates with iron. Therefore, the oxidation of As (III) to As (V) improves the effectiveness of arsenic removal technology. The oxidizing agents used for this conversion are oxygen, powdered active carbon, UV radiation, free chlorine, hypochlorite, potassium permanganate, ozone and also sunlight. Some of the removal techniques that can be adopted are: 1. Coagulation-flocculation-Sedimentation and Fig. 2: Schematics of the design of a Deep Exploratory Well (Using Filtration using Alum, Ferric alum lime, etc., cement sealing techniques). Proper designing of tubewells by putting 2. Ion exchange Resins, cement sealing against appropriate thickness of clay bed can prevent vertical percolation of arsenic rich water from shallow aquifer into 3. Adsorption using activated alumina, granulated deeper aquifer. The leakage of arsenic water from the shallow aquifer ferric hydroxide, iron coated sand, activated should be prevented adopting proper cement sealing techniques. The carbon, laterites, etc., cement sealing is an effective sealing for separation of upper aquifer 4. Membrane Techniques using Reverse Osmosis from the deeper aquifer. The aim of this technique is to place thoroughly mixed cement slurry against the impervious layer or Electrodialysis, between the casing and the wall of the borehole either by gravity or 5. Biological method using Phyto-remediation and under pressure through pump. Practically it is the filling up of Bacterial removal, and, openings principally to retain the impervious character so that there 6. Adsorption of arsenic by colloidal media is no percolation from the upper aquifer to the lower aquifer. The suspended in water and application of cement slurry consists of ordinary/ quick settling cement and water. A little clay is added in cement water mix to improve the flowing membrane based separation technique using properties. 40 kg of cement should be mixed with 20-25 litres of ceramic micro – filtration membrane. water with a specific gravity of 1.8. About 2 to 6 % of bentonite is Rain Water Harvesting: Rain water harvesting may be added to this slurry to improve its workability. About 30 cm of fine adopted if appropriate conservation structure is available sand layer should be placed at the top of the gravel packing before the cement grouting operation. Setting time of 72 hrs for ordinary to facilitate collection. Water conserved in such a way cement and 30 hrs for quick setting cement may be allowed and no needs to undergo filtration, and disinfections before it is work is to be done till the cement is fully set. put to use for public supply. This will provide an option

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Fig. 3: Map of West Bengal showing the Arsenic Contaminated Areas (Source: PHED, Govt. of West Bengal)

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0.06 0.05 0.05 0.05 0.04 0.04 0.04 0.03 0.03 0.03 0.02 0.02

(mg/l) 0.01 (mg/l) 0.01 0 Purbasthali I Purbasthali II 0

Arsenic Level Arsenic inGroundwater (Hematpur) (Chatani) Level Arsenic inGroundwater Haldibari (Dhaprahat) Block/ Location Block/ Location

Fig. 4: Graphical Representation of Arsenic Level in Groundwater for Fig. 5: Graphical Representation of Arsenic Level in Groundwater for the affected Blocks of Burdwan (E & W) District the affected Blocks of Coochbehar District 0.06 0.052 0.012 0.01 0.05 0.04 0.01 0.04 0.008 0.03 0.02 0.006 0.02 0.004 0.01 0.002 Arsenic Level Arsenic in 0 ArsenicLevel in 0 Groundwater(mg/l) Srirampur-Uttarpara Balagarh (Jirat) Balagarh Groundwater(mg/l) Domjur (Uttarpara) (Milangarh) (Ramrajatala) Block/ Location Block/ Location

Fig. 6: Graphical Representation of Arsenic Level in Groundwater for the affected Blocks Fig. 7: Graphical Representation of Arsenic Level of Hooghly District in Groundwater for the affected Blocks of Howrah District

0.06 0.05 0.05 0.05 0.04 0.04 0.04 0.03 0.03 0.03 0.02 0.02 0.02 0.02

(mg/l) 0.01 0 Arseni cArseni Level in Groundwater

Block/ Location

Fig. 8(a): Graphical Representation of Arsenic Level in Groundwater (0.01-0.05 mg/l) for the affected Blocks of Malda District

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0.35 0.302 0.3 0.25 0.2 0.15 0.138 0.15 0.131

(mg/l) 0.115 0.082 0.1 0.078 0.065 0.05

Arsenic Level Arsenic Groundwater in 0

Block/ Location

Fig. 8(b): Graphical Representation of Arsenic Level in Groundwater (>0.05 mg/l) for the affected Blocks of Malda District 0.06

0.05 0.05 0.05 0.05

0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04

0.03 0.03 0.03 (mg/l) 0.02 0.02 0.02 0.02 0.02

0.01 0.01 0.01 0.01 Arsenic Level Arsenic Groundwater in 0.01

Block/ Location

Fig. 9(a): Graphical Representation of Arsenic Level in Groundwater (0.01-0.05 mg/l) for the affected Blocks of Murshidabad District

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0.45 0.405 0.4 0.35 0.3 0.265 0.25 0.225 0.186 0.2 0.15 0.164 0.15 (mg/l) 0.094 0.1 0.055 0.052 0.071 0.058 0.065 0.051 0.065 0.05 0 Arsenic Level Arsenic Groundwater in

Block/ Location

Fig. 9(b): Graphical Representation of Arsenic Level in Groundwater (>0.05 mg/l) for the affected Blocks of Murshidabad District 0.06

0.05 0.05 0.05 0.05 0.05

0.04 0.04 0.04 0.04 0.04 0.04 0.04

0.03 0.03 0.03 0.03 0.03 (mg/l) 0.02 0.02 0.02

0.01 Arsenic Level ArsenicLevel in Groundwater 0.01

Block/ Location

Fig. 10(a): Graphical Representation of Arsenic Level in Groundwater (0.01-0.05 mg/l) for the affected Blocks of Nadia District

0.35 0.332 0.3 0.25 0.2 0.184 0.148

(mg/l) 0.15 0.119 0.082 0.1 0.063 0.065 0.076 0.05

Arsenic Level ArsenicLevel in Groundwater 0

Block/ Location

Fig. 10(b): Graphical Representation of Arsenic Level in Groundwater (>0.05 mg/l) for the affected Blocks of Nadia District 0.06 0.05 0.05 0.05 0.04 0.04 0.04 0.04 0.04 0.04 0.03 0.03 0.03 0.03 0.03 (mg/l) 0.02 0.02 0.02 0.02 0.02 0.01 0.01

Arsenic Level ArsenicLevel in Groundwater 0.01

Block/ Location

Fig. 11(a): Graphical Representation of Arsenic Level in Groundwater (0.01-0.05 mg/l) for the affected Blocks of 24 Parganas (N) District

0.8 0.761 0.7 0.6 0.5 0.4 0.265 0.282 0.3 0.215 0.143 0.124 0.2 0.089 0.072 0.086 (mg/l) 0.059 0.1 0.056 0 Aresenic LevelAresenic in Groundwater

Block/ Location

Fig. 11(b): Graphical Representation of Arsenic Level in Groundwater (>0.05 mg/l) for the affected Blocks of 24 Parganas (N) District 0.025 0.09 0.083 0.02 0.08 0.02 0.07 0.06 0.015 0.05 0.01 0.01 0.01 (mg/l) 0.01

(mg/l) 0.04 0.03 0.005 0.02 Arsenic Level Level Arsenic in Groundwater 0 Level Arsenic inGroundwater 0.01 Bhangar I Bhangar II Sonarpur Baruipur 0 (Kantatala) (Kulti I) (Khiddaha) (Ramnagar) Bishnupur II (Dhopar More) Block/ Location Block/ Location

Fig. 12(a): Graphical Representation of Arsenic Level in Groundwater Fig. 12(b): Graphical Representation of Arsenic Level in (0.01-0.05 mg/l) for the affected Blocks of 24 Parganas (S) District Groundwater (>0.05 mg/l) for the affected Blocks of 24 Parganas (S) District

identified with the problems of high Arsenic IV. CONCLUSION concentration in ground water. ‹ The Bengal Delta plain (BDP) covering

‹ Arsenic contamination of groundwater and Bangladesh and West Bengal in India is related health hazards are becoming high- presently facing the most severe cases of profile problems throughout the world. A ground water Arsenic contamination. The large number of Aquifers have been other parts of the country having Arsenic infested ground water include parts of Bihar,

ISSN : 2581-7175 ©IJSRED: All Rights are Reserved Page 670 International Journal of Scientific Research and Engineering Development-– Volume 3 Issue 2, Mar-Apr 2020 Available at www.ijsred.com Uttar Pradesh, Chhattisgarh, Jharkhand, V. REFERENCES Assam & Manipur. ‹ An arsenic contamination in India is mainly [1] Ray, A., Talukdar, T., Srivastava, K.K., geogenic and mostly occurs in “Arsenic Contamination of Groundwater in unconsolidated sediments except in some West Bengal - Milestones Reached & Hurdles parts of North Bengal where it occurs in the Ahead ”, Central Ground Water Board, Govt. aquifers in Precambrian rocks. Of India, ‹ Arsenic infested area of West Bengal forms [2] “Arsenic Hotspot in Groundwater in India ”, a part of Ganga-Bhagirathi delta, Central Ground Water Board, Govt. Of India, comprising succession of thick quaternary [3] “Arsenic in Groundwater in India ”, Bhu-Jal sediments and mainly restricted in the News, (2009), Central Ground Water Board, Upper Delta Plain within a shallow depth. In Govt. Of India. West Bengal Arsenic free aquifers have been identified (by CGWB) in the depth zone of 120-160 mbgl and 200-250 mbgl where deep exploratory tubewells can be constructed with suitable design to get Arsenic free water. ‹ Various Arsenic mitigation options include using surface sources, exploring and harnessing alternate arsenic free aquifer, removal of Arsenic from ground water using treatment filters and rainwater harvesting.

Fig. 13: Schematics of Tube Well Design in Arsenic Infected Area