Groundwater arsenic contamination in Manipur, one of the seven ...

Environ Geol DOI 10.1007/s00254-007-1176-x

ORIGINAL ARTICLE

Groundwater arsenic contamination in Manipur, one of the seven North-Eastern Hill states of India: a future danger Dipankar Chakraborti Æ E. Jayantakumar Singh Æ Bhaskar Das Æ Babar Ali Shah Æ M. Amir Hossain Æ Bishwajit Nayak Æ Sad Ahamed Æ N. Rajmuhon Singh

Received: 13 April 2007 / Accepted: 29 December 2007 Ó Springer-Verlag 2008

Abstract Manipur State, with a population of 2.29 million, is one of the seven North-Eastern Hill states in India, and is severely affected by groundwater arsenic contamination. Manipur has nine districts out of which four are in Manipur Valley where 59% of the people live on 10% of the land. These four districts are all arsenic contaminated. We analysed water samples from 628 tubewells for arsenic out of an expected total 2,014 tubewells in the Manipur Valley. Analyzed samples, 63.3%, contained [10 lg/l of arsenic, 23.2% between 10 and 50 lg/l, and 40% [50 lg/l. The percentages of contaminated wells above 10 and 50 lg/l are higher than in other arsenic affected states and countries of the Ganga–Meghna–Brahmaputra (GMB) Plain. Unlike on the GMB plains, in Manipur there is no systematic relation between arsenic concentration and the depth of tubewells. The source of arsenic in GMB Plain is sediments derived from the Himalaya and surrounding mountains. North-Eastern Hill Present Address: D. Chakraborti (&) E. J. Singh B. Das B. A. Shah M. A. Hossain B. Nayak S. Ahamed School of Environmental Studies, Jadavpur University, Kolkata 700032, India e-mail: [email protected] URL: www.soesju.org B. A. Shah Department of Geological Sciences, Jadavpur University, Kolkata 700032, India M. A. Hossain Institute of Statistical Research and Training, University of Dhaka, Dhaka, Bangladesh N. R. Singh Department of Chemistry, Manipur University, Canchipur, Manipur 95003, India

states were formed at late phase of Himalaya orogeny, and so it will be found in the future that groundwater arsenic contamination in the valleys of other North-Eastern Hill states. Arsenic contaminated aquifers in Manipur Valley are mainly located within the Newer Alluvium. In Manipur, the high rainfall and abundant surface water resources can be exploited to avoid repeating the mass arsenic poisoning that has occurred on the GMB plains. Keywords Groundwater arsenic contamination North-Eastern Hill states Manipur Valley Arsenic with depth of tubewell Watershed management

Introduction Based on 20 years of surveys of groundwater arsenic contamination and its health effects on the Ganga– Meghna–Brahmaputra (GMB) Plains, with a population of over 500 million, we have found that significant portions of all the states on the Ganga Plain (Uttar Pradesh, Bihar, Jharkhand, West Bengal), some parts of the Brahmaputra plain (Assam), and most of the plains of Bangladesh are arsenic affected (Chakraborti et al. 2004). The history of arsenic discoveries in states and countries in GMP-Plain is presented chronologically in Table 1. Except for a preliminary report by Singh (2004) on some areas in five of the seven North-Eastern Hill states, and our work on Assam (Chakraborti et al. 2004), no other published data are available on groundwater arsenic contamination in North-Eastern Hill states of India. In Manipur, Singh (2004) analysed 12 hand tubewell water samples from Kakching Municipality in Thoubal district, of which 6 contained [50 lg/l of arsenic.

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Environ Geol Table 1 History of arsenic discoveries in GMB Plain in chronological order

Year

Reference

1976

Chandigarh, North-India

Datta and Kaul (1976)

1984

West Bengal, India

Garai et al. (1984)

1992

Bangladesh

Dhar et al. (1997)

1995

West Bengal incident came to limelight International conference (1995)

1998

Bangladesh incident came to limelight

International conference (1998)

2001

Nepal

Shrestha et al. (2003)

2002

Bihar, India

Chakraborti et al. (2003)

October–December 2003

Uttar Pradesh, India


December 2003–January 2004 Jharkhand, India


January–February 2004


From the available reports (Chakraborti et al. 2004; Nickson et al. 2005) it has been noticed that most of the arsenic affected floodplains in Asia are by the side of the rivers that originate in the Himalayas or Tibet Plateau. Thus it is considered that Himalayas and surrounding mountains are potential sources of arsenic bearing minerals. Because the North-Eastern Hill states are part of the Himalayan mountain range, we anticipated finding groundwater arsenic contamination in the Newer Alluvium (Holocene) of the Brahmaputra, Barak, Surma and Imphal rivers. These basins cover parts of all the seven NorthEastern Hill states: Arunachal Pradesh, Assam, Meghalaya, Tripura, Nagaland, Manipur and Mizoram (Fig. 1a). The objective of this paper is to describe the magnitude and severity of arsenic contamination in the four valley districts of Manipur State which form only 10% of the state but are home to about 60% of the population. We further demonstrate the potential for watershed management and surface water resources to avoid the danger of arsenic poisoning.

Regional setting Manipur State is surrounded by mountains with plain land (valley) at the centre, known as Manipur Valley. It has an area of 22,327 km2 and a population 2.29 million (2001 census). The climate is subtropical with annual temperature ranging from 0 to 36°C and annual rainfall varying from 933 to 2,593 mm. The majority of the population depends on agriculture. Manipur consists of nine districts (Fig. 1b), each having 3–4 blocks. Four districts are in plain land and the rest are in hilly areas. The four plain districts of the Manipur Valley occupy 10% of the total area (Fig. 1c) of the state and are home to 59% of the state’s total population live in these four districts. To understand the state of groundwater arsenic contamination in the Manipur Valley, we surveyed all four districts (Fig. 1c): Imphal East (709 km2, population

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Location

Assam, India

394,876), Imphal West (519 km2, population 444,382), Thoubal (514 km2, population 364,140) and Bishnupur (496 km2, population 208,368). The area is mainly underlain by the Holocene Newer Alluvium, and is the main area for tubewell exploitation in Manipur, and where tubewells have been installed at depths of between 5 and 120 m.

Geology of Manipur The Hills of Manipur lie between the Naga–Patkai Hills on the north and northeast, and the Chin-hills on the south forming an integral part of the Indo-Myanmar (Burma) Ranges (IMR). The structural and tectonic pattern is transitional between the NE–SW trending pattern of Naga– Patkai Hills and N–S trend of Mizoram and Chin Hills (Brunnschweiler 1974). It comprises geologically young rock formations that were uplifted by the Tertiary orogeny of the Himalayas from the shallow bed of the Tethys Sea. The rocks are dominantly Tertiary and Cretaceous sediments with minor igneous and metamorphic rocks. Flysch sediments of Tertiary age underlie nearly 70% of the state (Soibam 1998). Disang and Barail flysch sediments underlie much of central Manipur. The oldest formation, the Disang Series (Eocene) comprises splintery shale with minor mudstone, siltstone, sandstone and limestone. The Disang is overlain by the Oligocene Barail Formation contained abundant carbonaceous matter. The Barail is succeeded by the predominantly argillaceous Surma and the Tipam formations. The sediments of the Surma basin is molasse (Nandy 1980). Ultrabasic igneous rocks, of the Ophiolite Zone, are intruded into the Disang Group in east of Manipur. The general tectonic trend of rock formations in the state is NNE-SSW, but varies between N–S and NE–SW, and locally NNW–SSE. Almost all the major structural elements such as folds reverse and thrust faults follow this regional strike/trend.

Environ Geol Fig. 1 a Groundwater arsenic contaminated area in Ganga–Meghna–Brahmaputra Plain, b Map showing all the nine districts in Manipur including the four (A–D) valley districts, c The map showing the study areas in Manipur Valley

Topographically, Manipur comprises a ridge and furrow terrain where sediments derived from surrounding ridges are deposited in the furrows (Soibam 1998). In the Manipur Valley, lenses of argillaceous sediments were deposited in the Assam–Arakan trough. Manipur is divisible into a central valley and the surrounding mountains. About 25% of the valley is occupied by lakes, wetlands, barren uplands and hillocks. The NNW–SSE oriented valley is oval shaped, and slopes gently to the south. The Imphal or Manipur River meanders through the Manipur Valley in a NW–SE direction (Fig. 1c) and passes through a gorge to flow out of the state to join the Chindwin River in Myanmar. The formation of the Manipur River and its tributaries that drain the area was closely connected with the upliftment of

the South Manipur Hills and subsequent erosion of the weak crest of the anticlinorium. There were multiple episodes of low energy, fluvio-lacustrine deposition during the Quaternary, and these sediments are encountered to depths of 150 m. Disconnected lenticular water bodies dominate the valley (Fig. 1c). The Manipur Valley has been infilled by thick alluvium which is subdivided into the Older (Pleistocene) and Newer Alluvium. The Older Alluvium is made up of clay, silt, coarse sand, gravel, pebble and boulders, deposited adjacent to the foothills and forming older river terraces in the lower part of Manipur Valley. The Newer Alluvium is composed of clay, sand, silt and dark clay with carbonaceous matter, deposited mainly in the central and upper part of the Manipur Valley.

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Sources of water in Manipur State At the beginning of the twentieth century, there were approximately 500 lakes in Manipur State (Manipur 2007) with innumerable small ponds, swamps and marshes along lakesides and inter-riverine tracts and many community and household ponds. Many of these water bodies no longer exist due to encroachments for paddy cultivation and human settlement. At present there are still a number of large and small lakes. Loktak in Bishnupur district is the largest and most important freshwater lake (289 km2) in the North Eastern Hill states and could be used as a potable water resource after appropriate treatment. There are 155 water bodies covering an area of 530 km2 (World Bank 2007). Two main rivers drain Manipur: the Barak drains the west and the Manipur drains the east, including the Manipur Valley. The Manipur catchment has an area of 6,332 km2 and an average annual yield is 51.9 9 108 m3. The Central Groundwater Board (CGWB) estimated the groundwater resource potential of the Manipur Valley to be around 44 9 106 m3 per annum (Mastec 2007). No previous information on the potability of the groundwater with respect to fluoride, arsenic, and other heavy metals was available. Manipur receives rainfall from the SW and NE monsoons, with an average annual rainfall of about 2,000 mm. A water balance calculation, considering water demand and the available surface water resources, by Mastec (2007) showed that the annual availability of 18.5 9 109 m3 of water is 66% in excess of current annual requirement of 11.1 9 109 m3 (up to 2000 AD). With the prospect of water recycling, various departments dealing with water resources and supply are optimistic that there is sufficient water to meet the long-term needs of the Manipur Valley.

Water use in Manipur State Before 1980, almost 100% of water used for domestic purposes was from rivers, lakes, ponds (local name Pukhris) and in hilly areas dug-wells and streams. Still now rainwater is the main source for agricultural water. With the increase in population from 1.0 million in 1971 to 2.29 million in 2001, use of land for human settlement, agricultural activities and extensive use of fertilizers, pesticides, insecticides, herbicides has not only reduced water availability but also led to deteriorating water quality. Presently groundwater is readily available. Our survey identified 1,173 Public Health Engineering Department (PHED) installed and 841 private tubewells. During interviews, villagers said that they do not like the taste of tubewell water and mainly drink pond water. It appears that most villagers are not aware of the danger of drinking untreated pond water. In some cases, there are indications that

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sufficient surface water is not available. For example, Kakching Municipality (Thoubal district) was previously supplied from a natural reservoir which dried up, and so PHED installed 52 hand tubewells and local people installed 90 tubewells. Similarly, when PHED could not get enough surface water to supply in Khundrakpam village (Imphal East) they installed a tubewell-based supply. Presently, there are 10 tubewell-based schemes covering 31 villages in the Manipur Valley (PHED 2006). At present, underground water is not used for agriculture but this may happen in the future, and could add to arsenic exposure via the food chain.

Hand tubewell use in the Manipur Valley Public Health Engineering Department installed the first tubewell in the Manipur Valley early in 1982, and the first private tubewell was installed in June 1982. PHED drilled more hand tubewells after 1991–1992, many more tubewells than private owners. PHED reported that they had installed 1,173 tubewells in the Manipur Valley up to 2006.

Methodology Sample collection and procedure for arsenic analysis In the four districts, our survey covered 8 of 9 blocks, 88 out of 490 villages, and 18 out of 28 municipal areas. Water samples were collected in acid pre-washed 10 ml polythene bottles. The bottles were kept overnight in dilute laboratory grade nitric acid (1:1) and finally washed with distilled water. Immediately after collection, 1 drop of dilute nitric acid (1:1) GR Grade was added as preservative. Arsenic and iron were determined from these samples. Spot urine samples were collected in the same pre-washed bottles, adding 2 drops of 50% hydrochloric acid as a preservative, and then kept in an ice-box during transport at Jadavpur University, by air, to the laboratory, where they were stored in a refrigerator at 4°C. Total arsenic in water was determined by flow-injectionhydride generation atomic absorption spectrometry (FIHG-AAS) and iron by Spectrophotometry. For urine samples, inorganic arsenic and its metabolites (arsenite, arsenate, monomethyl arsonic acid and dimethyl arsinic acid) were measured by FI-HG-AAS with no further chemical treatment. Under these experimental conditions of FI-HG-AAS, arsenobetaine and arsenocholine present in urine are not detected (Chatterjee et al. 1995). The details of sample collection, analytical procedure for water and urine samples and details of the instrument and flow injection system were as reported earlier (Chatterjee et al. 1995; Samanta et al. 1999).

841 2,014 1,173 41.7 58.3 262 366 628

14 Bishnupur

Total

9 132 123 7.1 92.9 1

196 Thoubal

13

54

422 707 285 59.7 40.3 117

140

79

377

798 442

323 14.3

44.6 55.4

85.7 20

124 278

Imphal West

120

Private (E) Public (D)

Imphal East

154

Total no. of predicted T/Ws in Manipur Valley [G = (F 9 100/D]) No. of T/Ws installed by PHED (Till March, 2006) (F) % of public and private T/Ws

No. of private T/Ws analysed for arsenic (C) No. of public T/Ws analysed for arsenic (B)

We analysed 628 of the estimated 2,014 hand tubewells in the Manipur Valley. Table 3 shows the frequency distribution of arsenic concentrations in tubewells. Figure 2a, b and c show the groundwater arsenic contamination status in three districts of Manipur State. Of the tubewells tested, 63.3% had arsenic[10 lg/l, 23.2% between 11 and 50 lg/l and 40% [50 lg/l. The cumulative frequency distribution of arsenic concentrations in four districts is presented in Fig. 3. The most severely arsenic-affected district was Thoubal, where 77.6% of tubewells contained [10 lg/l and 44.4% [50 lg/l. The least affected district was Bishnupur, where 21.4% of wells contained [10 lg/l and 7.1% [50 lg/l.

Total No. of T/Ws analysed for arsenic (A)

Groundwater arsenic contamination in four districts of the Manipur Valley

Districts in Manipur Valley

All the tubewells sample were drilled wells. The age of wells was collected from PHED (2006) for 565 of 628 tubewells sampled, and ranged from less than 1–25 years. The average ages of public and private tubewells were 11 and 7 years, respectively. Depth information for 579 tubewells indicated range of 5–120 m, with an average of 50 m. Based on door to door interviews indicated an average of 233 users for each tubewell. Of the 628 water samples analysed for arsenic, 366 (58.3%) were from PHED tubewells and 262 (41.7%) from private tubewells. We do not know the total number of private tubewells, but from the ratio (1.4:1) of PHED to private tubewells we surveyed, the numbers of public and private tubewells were estimated to be 1,173 (June 1982 to March 2006) and 841, respectively (Table 2). However, in Thoubal district, there were more private (117) than public (79) tubewells (1:1.5). The reason for the higher number of private tubewells was because the reservoir from which PHED supplied Kakching Municipality dried up. So, the people of Kakching had no practical alternative to installing private tubewells. This practice is expected to continue.

Table 2 The number of public and private tubewells in Manipur Valley analysed and predicted number of private tubewells as per our survey

Results and discussion

Predicted no. of private T/Ws in Manipur Valley (H = G-F)

The accuracy of our analytical method using FI-HGAAS was verified by analyzing Standard Reference Materials [CRM (BND 301) NPL, India water (certified value 990 ± 200 lg/l; found 960 ± 40 lg/l); SRM (quality control sample for trace metal analysis) from USEPA Environmental Monitoring and Support Laboratory, Cincinnati, OH, USA (certified value 17.6 ± 2.21 lg/l; found 16 ± 3.5 lg/l); Urine SRM 2670, NIST, USA (elevated level)(certified value 480 ± 100 lg/l; found 477 ± 30 lg/l)].

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628 (100.0%) 1 (0.2%)

1 (0.2%)

1 (0.2%)

196 (100.0%)

14 (100.0%)

278 (100.0%) 1 (0.4%) 1 (0.4%) -

1 (0.7%)

[500 251–300

301–500

Total

140 (100.0%)

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Figure 2c shows the status of arsenic contamination in Kakching Municipality as per our survey. In the three districts, Imphal west, Imphal East and Thoubal the proportion of groundwater sources with arsenic contamination exceeding 10 and 50 lg/l are quite high. A comparison of arsenic concentrations in all states and countries on the GMB plains and the Manipur Valley is presented in Table 4. Although the number of hand tubewells in Manipur is much less, the proportions of arsenic concentrations [10 and [50 lg/l are higher than on the GMB plains (Table 4). The proportions are similar to those in the most severely affected districts of Bangladesh.

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11 (1.75%) 36 (5.7%) 64 (10.2%) 146 (23.2%) 220 (35.0%)

11 (1.75%)

137 (21.8%)

–

1 (0.5%) 1 (0.5%)

1 (7.1%)

85 (43.4%)

-

65 (33.2%)

2 (14.3%) –

4 (2.0%) 40 (20.4%)

11 (78.6%)

11 (4.0%)

– 2 (1.4%)

33 (11.9%) 43 (15.4%)

19 (13.6%) 16 (11.4%) 30 (21.5%)

36 (12.9%) 49 (17.6%)

3 (2.1%) 69 (49.3%)

100 (36.0%)

4 (1.4%)

Of 579 tested tubewells, 71% were 30–70 m deep, and the average depth was 50 m with a standard deviation 20 m. Figure 4 compares the relationship between depth and arsenic concentration of tubewells in the arsenic areas of the GMB plains with the Manipur Valley. For comparison purposes we considered only depths up to 120 m because this was depth of the deepest tubewell in the Manipur Valley. Fig. 4 shows that the depth trend in Manipur Valley differs from the GMB plains in that arsenic concentrations do not vary systematically with depth. In all other cases, arsenic concentrations increased to a maximum in the range 20–40 m. In the GMB plains, deep aquifers, preferably 200 m (except unconfined zone and leaky aquifers) are considered to be arsenic safe. In Manipur, even tubewells [100 m cannot be assumed to be safe. The average number of users per tubewell in Manipur was 233 Valley, compared to 27, 24, 20, 18 and 16 in West Bengal, Bangladesh, Bihar, Jharkhand, Uttar Pradesh, respectively. Thus, it may be concluded that the tubewell culture in Manipur has only just started.

Correlation of iron concentration with arsenic Iron concentrations in 416 samples ranged from 40 to 39,537 lg/l, with a median of 3,138 lg/l and a mean of 6,150 lg/l (standard deviation 7,811 lg/l). Table 5 shows that iron concentrations in tubewells in the Manipur Valley are similar to those on the GMB plains, and here also the correlation between iron and arsenic is poor (Fig. 5).

Total

Thoubal

Imphal West

Imphal East

Arsenic in urine samples Bishnupur

51–100 11–50 4–10 \= 3

Arsenic concentration range (lg/l) Districts in Manipur Valley

Table 3 Arsenic concentration distribution in four districts of Manipur Valley

101–150

151–200

201–250

Variation of arsenic concentration with tubewell depth

Elevated arsenic concentration in urine is an indicator of recent exposure. Assuming excretion of 1.5 l urine per day, arsenic concentrations in 56 urine samples from the

Environ Geol

Fig. 2 Groundwater arsenic contamination status in three districts of Manipur Valley. a Imphal West, b Imphal East, c Kakching Municipality area and Thoubal Block of Thoubal District

Fig. 3 Cumulative frequency (%) distribution of the tubewells against different arsenic concentration ranges for four districts of Manipur Valley

municipal areas of Imphal East, Imphal West, and Thoubal range from 13 to 500 g/day, with a median concentration of 57 g/day, and mean of 89 g/day (standard deviation 86.5 g/day) respectively. In 66.1% samples, arsenic concentrations exceeded 40 lg/day (normal excretion of

arsenic in urine ranges from 5 to 40 g/day). The arsenic concentrations in urine samples ranged from 13 to 500 lg/day. Figure 6 represents the histogram of the arsenic concentration in urine samples. From Fig. 6 it appears that 19 (34%) samples contained arsenic within the normal range of arsenic in urine (5–40 g/day) and the remaining 37 (66%) samples exceeded the normal range. The results (Fig. 6) indicate recent exposure to arsenic in the Manipur Valley population. Our analytical system measures inorganic arsenic metabolites (As3+, As5+, MMA, DMA), but does not detect arsenobetaine, the main constituent in sea food. So, the higher arsenic metabolites represent exposure mainly from drinking water. Table 6 compares arsenic in urine in states and countries in GMB Plain and the Manipur Valley.

Conclusion and recommendations Groundwater contamination affects all four districts of the Manipur Valley and 63.3% of hand tubewells exceed the WHO guideline value for arsenic in drinking water

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Environ Geol Table 4 Comparison of arsenic concentration above 10 and 50 lg/l in arsenic affected states and countries in GMB Plain with Manipur Valley States and countries in GMB Plain

% Samples above 10 lg/l


Maximum arsenic concentration

Reference

4,780

46.5

27.7

3,191

Ahamed et al. (2008)

19,961

32.7

17.8

2,182

Ahamed (2006)

3,354

35.0

15.0

1,018


West Bengal

140,150

48.1

23.8

3,700


Bangladesh

50,808

40.3

26.3

4,730


628

63.3

40.0

502

Uttar Pradesh Bihar Jharkhand

Manipur Valley

Total samples analysed for arsenic

This Study

Fig. 5 The correlation between arsenic and iron in Manipur Valley Fig. 4 Relationship between depth and arsenic concentration of tubewells for arsenic affected states and countries in Ganga–Meghna– Brahmaputra (GMB) Plain and of Manipur Valley. WB West Bengal, BD Bangladesh, UP Uttar Pradesh, JK Jharkhand

(10 g/l) and 40% exceed the Indian Standard of 50 lg/l. Unlike on the GMB plains, there is no systematic relation between arsenic concentration and the depth of tubewells but in the Manipur Valley arsenic contamination does not vary with depth. Because 59% of the population of Manipur lives in the four districts of the Manipur Valley, the situation will become more serious if the people continue drinking contaminated tubewell water. Four decades ago, the villagers of West Bengal and Bangladesh

were reluctant to use underground water but now a tubewell at one’s house is perceived to be as essential as food. Groundwater is a major source for drinking water and water for irrigation. During our 1-year survey in the Manipur Valley, we recognized that the villagers do not like the taste of tubewell water and still prefer the water from community ponds or other surface sources such as rivers, lakes, reservoirs in hilly areas etc. Although the average rainfall is high (2,000 mm/annum), people do not use it because there are plenty of other available resources. However, in nearby state of Mizoram, where there are fewer lakes and ponds, for generations people have used rainwater and collected stream water in small open tanks known as Tunikhor.

Table 5 Comparison of iron concentrations in hand tubewells of arsenic affected states and countries in GMB Plain and Manipur Valley States and countries in GMB Plain Uttar Pradesh

Total Samples analysed

% Samples above 1,000 lg/l





Max. conc.

94.5

77.9

31.9

2.6

0.5

0.3

43,575

95

79.5

25.5

2.3

0.3

0.17

21,630

559

89.3

52.6

16.6

1.6

17,050

93.2

75.6

28.3

4.3

0.9

0.4

77,000

Bangladesh

547

99.5

95.2

42.6

1.3

0.4

0.2

48,773

Manipur Valley

416

97.4

86.3

31.7

17.5

13.0

9.6

39,537

Bihar Jharkhand West Bengal

123

583


1,414

12,589

Environ Geol

Fig. 6 Histogram of arsenic concentration (lg/day) in urine samples of the study population in Manipur Valley

Table 6 Comparison of arsenic metabolites in urine of the study group from arsenic affected states and countries in GMB Plain and that of Manipur Valley % of samples above normal levela

Reference

Millions are drinking arsenic contaminated water, and many are at grave health risk, and we fear that the experiences of West Bengal and Bangladesh will be repeated. West Bengal and Bangladesh are called lands of rivers with flooded river basins, wetlands, ox-bow lakes, 2,000 mm of annual rainfall, yet the villagers depend mainly on tubewell water for drinking and irrigation. Even when surface water is available, they use groundwater due to its easy access, and so the tubewell culture dominates, but meanwhile there is practically no watershed management. The mistakes made in West Bengal and Bangladesh should not be repeated in Manipur. The arsenic problem in Manipur has just been discovered, and at present, people are reluctant to use tubewell water. In this condition, with careful utilization of existing surface water, rainwater and economic utilization along with the education of the villagers and their active participation appear to be the viable approaches to stop the future arsenic danger in Manipur. Acknowledgments Funds from Hamdard National Foundation to carry out arsenic related work in North Eastern Hill States for 5 years is greatly appreciated. The authors sincerely thank to K. Rajen (Geophysicist, IPD, PHED, Govt. of Manipur) for providing relevant database, S. Ibotombi and E. Ranjitkumar from Earth Sciences Department of Manipur University for their constructive suggestions.

States and countries in GMB Plain

Total number of urine samples analysed

West Bengal

12,000

89

Bangladesh

1,084

95

SOES (2007)

Bihar

51

98


References

Jharkhand

54

100

Unpublished data

Uttar Pradesh

80

95


Manipur

56

66.1

This Study

Ahamed S (2006) Groundwater arsenic contamination and its health effects in the states of Bihar and Uttar Pradesh, India (Unpublished Ph.D. Thesis). Jadavpur University, Kolkata Ahamed S, Sengupta MK, Mukherjee A, Hossain MA, Das B, Nayak B, Pal A, Mukherjee SC, Pati S, Dutta RN, Chatterjee G, Mukherjee A, Srivastava R, Chakraborti D (2006) Groundwater arsenic contamination in middle Ganga plain, Uttar PradeshIndia: a future danger? Sci Total Environ 370:310–322 Ahamed S, Das B, Hossain MA, Nayak B, Pal A, E. Jayantakumar Singh, Sengupta MK, Mukherjee SC, Pati S, Dutta RN, Kshitish Chandra Saha, Quazi Quamruzzaman, Chakraborti D (2008) Groundwater arsenic contamination and its health effects in Ganga–Meghna–Brahmaputra Plain and its surroundings. Trace Elem Med (in press) Brunnschweiler RO (1974) Indoburman ranges. Geol Soc Lond Spl Pub 4:279–299 Chakraborti D, Mukherjee SC, Pati S, Sengupta MK, Rahman MM, Chowdhury UK, Lodh D, Chanda CR, Chakraborti AK, Basu GK (2003) Arsenic groundwater contamination in middle Ganga plain, Bihar, India: a future danger environ. Health Perspect 111:1194–1201 Chakraborti D, Sengupta MK, Rahman MM, Ahamed S, Chowdhury UK, Hossain MA, Mukherjee SC, Pati S, Saha KC, Dutta RN, Zaman QQ (2004) Groundwater arsenic contamination and its health effects in the Ganga–Meghna–Brahmaputra plain. J Environ Monit 6:74–83 Chatterjee A, Das D, Mandal BK, Chowdhury TR, Samanta G, Chakraborti D (1995) Arsenic in ground water in six districts of West Bengal, India: the biggest arsenic calamity in the world, Part I. Arsenic species in drinking water and urine of the affected people. Analyst 120:643–650

SOES (2007)

a

Normal excretion of arsenic in urine ranges from 5 to 40 lg/day (assuming a typical volunteer excretes 1.5 l of urine per day) (Farmer and Johnson 1990)

The PHED of Manipur State pipes treated water to urban and some rural areas from rivers, lakes and natural water reservoirs from hilly areas. However, the water supplied in most areas, even in the capital, is inadequate in quantity and irregular. In rural areas the water supply is even worse. Outside urban areas, ponds are the most common traditional source of drinking water and villagers continued to drink this unsafe water. When the first water came out from underground in West Bengal in early 1960s, the villagers called it ‘‘the devil’s water’’. But later they changed their minds as the water irrigated rice crops all the year round and potable water was available at the doorstep. But the economic gain has come at tragic human cost. After West Bengal’s arsenic experience, we came to know that the same problem exists in Bangladesh, Bihar, Uttar Pradesh, Jharkhand and Assam.

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