Full text of DOI:10.1080/02508060108686929

This article was downloaded by: [Florida Atlantic University]
On: 18 November 2014, At: 23:57
Publisher: Routledge
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,
37-41 Mortimer Street, London W1T 3JH, UK
Water International
Publication details, including instructions for authors and subscription information:
http://www.tandfonline.com/loi/rwin20
Extent and Severity of Groundwater Arsenic
Contamination in Bangladesh
a
a
c
Md. Abul Fazal , Toshihiko Kawachi & Eiji Ichion
a
Bangladesh Agricultural Research Institute , Gazipur, Bangladesh
IWRA, Kyoto University , Kyoto, Japan
b
c
Ishikawa Agricultural College , Ishikawa, Japan
Published online: 22 Jan 2009.
To cite this article: Md. Abul Fazal , Toshihiko Kawachi & Eiji Ichion (2001) Extent and Severity of Groundwater Arsenic
Contamination in Bangladesh, Water International, 26:3, 370-379, DOI: 10.1080/02508060108686929
To link to this article: http://dx.doi.org/10.1080/02508060108686929
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained
in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no
representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the
Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and
are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and
should be independently verified with primary sources of information. Taylor and Francis shall not be liable for
any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever
or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of
the Content.
This article may be used for research, teaching, and private study purposes. Any substantial or systematic
reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any
form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://
www.tandfonline.com/page/terms-and-conditions

International Water Resources Association
Water International, Volume 26, Number 3, Pages 370–379, September 2001
Extent and Severity of Groundwater Arsenic
Contamination in Bangladesh
Md. Abul Fazal, Bangladesh Agricultural Research Institute, Gazipur, Bangladesh,
Toshihiko Kawachi, Member IWRA, Kyoto University, Kyoto, Japan, and Eiji Ichion,
Ishikawa Agricultural College, Ishikawa, Japan
Abstract: In Bangladesh, the majority of the irrigation and drinking water is supplied from under-
ground sources due to the limitation of surface water. In recent years, arsenic contamination has emerged
as a fresh blow to the country. This paper gives an overview of the extent and severity of groundwater
arsenic contamination in Bangladesh, as well as a review of the latest statistics and findings of numerous
investigations about this issue. Recent reports of the British Geological Survey show that the groundwa-
ter in all 61 surveyed districts out of 64 is now contaminated with arsenic. On the other hand, a survey
report of School of Environmental Studies, Jadavpur University, and Dhaka Community Hospital shows
4
7 districts are contaminated. The population exposed to the arsenic poisoning through drinking water
is more than 25 million. In regard to arsenic pollution, Bangladesh is the most vulnerable country in the
world. Unfortunately, until now, the cause of groundwater arsenic contamination has not been detected.
Initially, several anthropogenic sources of arsenic were presented. Gradually, all were rejected based on
the field observations. Finally, it was recognized that the source of arsenic is in the geological deposits.
The two prevailing hypotheses, pyrite oxidation and oxy-hydroxide reduction, describe the cause of
contamination. However, neither has been studied thoroughly with accurate field data. Therefore, the
verdict is still out whether to support one hypothesis over the other. Thousands of people are suffering
from arsenic diseases ranging from melanosis to skin cancer and gangrene, and many have even died.
Unfortunately, there is no specific treatment for chronic arsenicosis, other than ceasing further intake of
arsenic contaminated water. To overcome this predicament, awareness of the problem and the creation
of watershed management are necessary.
Keywords: Bangladesh, groundwater, arsenic contamination, causes, remedies.
DCH, 2000). The population exposed to the arsenic poi-
Introduction
soning through drinking water is more than 25 million.
Bangladesh lies in the northeastern part of South Asia Thousands of people are suffering from arsenic diseases
between 20º34’ and 26º38’ north latitude and 88º01’ and ranging from melanosis to skin cancer and gangrene. In
9
2º41’east longitude. She is bounded by India on the west, 241 villages where arsenic patients were suspected, thou-
the north and the northeast, Myanmar on the southeast, sands of arsenic patients and a total of 40 deaths due to
and the Bay of Bangal on the south. The area of the coun- arsenic-related diseases were identified by the SOES-
2
try is 147,570 km with an estimated population of 129.6 DCH survey (SOES-DCH, 2000).
million for the year 2000 (BBS, 1998). The country is known
Presently, Bangladesh has about 1.8 million hand
as a land of natural calamities, where flood and drought tubewells (HTWs) supplying drinking water from under-
are the normal phenomena. In recent years, arsenic poi- ground sources to more than 90 percent of 129.6 million
soning has emerged as an additional burden to the country. people. She has also about 26,000 deep tubewells (DTWs),
In Bangladesh, the Department of Public Health Engi- 630,000 shallow tubewells (STWs), and 140,000 manual
neering (DPHE) first detected arsenic in drinking water in suction lift wells (MSLWs) lifting groundwater for irriga-
1
1
993, and the issue came in lime light at the beginning of tion purpose (NMIDP, 1998). Using all these wells, water
3
995. Recent findings of the British Geological Survey of more than 12,000 million m is pumped every year from
(
BGS) show that groundwater of 61 surveyed districts, the underground water sources. Over 90 percent of all
out of a total of 64, is contaminated with arsenic (BGS, groundwater abstraction is used for irrigation. Unfortu-
999). However, survey results of the School of Environ- nately, many of the tubewells are not supplying safe drink-
mental Studies (SOES) and Dhaka Community Hospital ing water; rather, they pump the arsenic contaminated
DCH) show that 47 districts are contaminated (SOES- groundwater. Until now, only 50,000 out of the above
1
(
370

Extent and Severity of Groundwater Arsenic Contamination in Bangladesh
371
mentioned tubewells have been investigated by various number of people suffering from arsenosis. Moreover,
government and non-government agencies. Although the there are some reports that contradict each other. This
government has a plan to survey at least all the tubewells paper describes the latest statistics of groundwater ar-
supplying drinking water, it has not completed this task. senic contamination in Bangladesh, its eventual causes and
Therefore, the actual picture of the severity of arsenic remedies.
contamination is not yet revealed.
At present, arsenic has been taken into account as a
Nature of Arsenic and its Occurrence
dangerous environmental pollution and detected as a seri-
ous health risk in many countries of the world. Arsenic
Arsenic is a metalloid element, which is brittle in na-
contamination has been reported from Argentina, Mexico, ture and gray or tin white in color. Arsenic cannot be found
Chile, USA, Taiwan, Mongolia, Thailand, Philippines, China, in nature as a free element. It can be found as a com-
Japan, India, as well as Bangladesh. But in terms of se- pound of oxygen, chloride, sulfur, carbon, hydrogen, lead,
verity of the problem, Bangladesh tops the list. Some of mercury, gold, and iron. There are as many as 150 species
the arsenic polluted countries of the world with the af- of arsenic bearing minerals that exist in the nature. How-
fected population are shown in Table 1.
ever, only three of them are considered as arsenic ore
The arsenic contamination is not only a health hazard because the amount of arsenic is higher in these three
for the people; it also affects the environment and creates compounds. Moreover, they are more available than other
social problems. Unfortunately, there is no treatment for arsenic compounds. These three compounds are: Realgar
arsenicosis, but people must stop drinking arsenic contami- or arsenic disulfide (As S ); Orpiment or arsenic tri-sul-
2
2
nated water, and government agencies should raise the fide (As S ); and Arsenopyrite or ferrous arsenic sulfide
(FeAsS). Arsenopyrite has been primarily identified as the
2
3
awareness of the population about the problem.
So far, three main reports (BGS, 1999; SOES-DCH, main source of arsenic pollution in Bangladesh. Chemi-
000; DCH, 2000) and many papers and articles (Karim, cally, arsenic compounds are two types: inorganic and or-
000a; Karim, 200b; Begum and Karim, 2000; Kamal and ganic. Inorganic arsenic is again divided into two types:
2
2
Karim, 2000; Karim et al., 1997; Nickson et al., 1998; trivalent and pentavalent. Inorganic arsenic is more toxic
Nickson et al., 1999; Adel, 2000; Husain, 2000; Bridge than the organic ones. The trivalent arsenic (arsenite, As
and Husain, 1999a; Bridge and Husain, 1999b; Bridge and III) is 60 times more toxic than the pentavalent arsenic
Husain, 2000a; Bridge and Husain, 2000b; Khalequzzaman, (arsenate, As V). Usually, there are four types of arsenic
1
etc.) related to Bangladesh groundwater arsenic contami- (H AsO ) and arsenate (H AsO ), which are commonly
999; Hossain et al. 2000; Anwarul Islam et al., 1998, compounds that exist in water, in inorganic form: arsenite
- -
2
3
2
4
nation have been published in different local and interna- found in the groundwater of Bangladesh, and in organic
tional journals, daily newspapers, Internet, etc. However, form: methyl arsenic acid (CH AsO(OH) ) and dimethyl
none has complete updated information about the extent arsenic acid ((CH ) As(OH)).
3
2
3
2
and severity of the problem, population exposed to con- Arsenic is found in low concentrations in naturally
tamination, cause of contamination and its remedy, and occurring materials comprising less than one percent of
Table 1. Arsenic Polluted Countries of the World With Affected Population and Their Reason
Name of
the Country
Year of
Pollution
Population Affected
by Arsenic
Maximum Range
of Pollution (mg/l)
Main Reason of Pollution
Natural soil pollution
Oxidation of arsenic bearing minerals
River cutting through arsenic bearing formation
Oxidation of pyrite, reduction of ferric oxide, etc.
Oxidation of pyrite
Over-irrigation
A tin mine
Geothermal power plant
Use of coal as fuel
Metal and coal mine
Argentina
Mexico
Chile
1938–1981
1963–1983
1957–1969
1972–1982
1961–1985
1962–1989
1987–1998
1992–1995
1953–1993
1945–1995
1978–1998
1993–2000
20,000
200,000
130,000*
3,000,000*
100,000
1,774
0.1–2.0
0.1–0.5
0.8–1.3
0.045–0.092
>0.05
>0.05
0.05–5.0
-
USA
Taiwan
Mongolia
Thailand
Philippines
China
Japan
India
Bangladesh
18,000*
39
1,546
-
-
217
200,000
21,000,000 (at least)
0.05–3.7
0.052–4.727
Over-exploitation of groundwater (pyrite oxidation)
Over-exploitation of groundwater (pyrite oxidation)
or arsenic released under reducing condition
* = Population at risk, actual affected is unknown and - = data not available.
Source: Akram (1997), BGS (1999), and SOES-DCH (2000).
IWRA, Water International, Volume 26, Number 3, September 2001

372
M.A. Fazal, T. Kawachi, and E. Ichion
rocks, coals, and soils. It is widely distributed in the soil were collected and tested by field-kits by the DPHE, GB,
profile as compound of different minerals and found in and NGO Forum to identify arsenic contaminated water
nominal amounts in all organisms. Most of Bangladesh wells. On the other hand, a total of 9,037 water samples
and the arsenic-affected areas of West Bengal, India, lie were collected and tested in the laboratory by the DCH/
on the Quaternary alluvial plains of the Bengal Basin. The SOES, DPHE, BUET, BCSIR, NRECA, DANIA, 18DTP
Garo-Rajmahal Gap broad alluvial plains of the Ganges (Eighteen District Towns Water Supply Project), Safiuallah,
and the Brahmaputra, so-called Himalayan Foredeep, ex- Nickson, BRAC, and BGS. In its recent reports, the BGS
tend to the northwest and northeast, respectively. To the has presented two separate figures: one based on field
north of this line, lie the crystalline rocks and meta-sedi- tests and another based on laboratory tests to describe the
ments of the great Himalayan thrust blocks. West Bengal extent of groundwater arsenic contamination in Bangladesh
(
Purulia District), Bihar, and the Shillong Plateau (north of (BGS, 1999). Though in both figures the index of arsenic
Sylhet and Mymensingh districts of Bangladesh) are ex- contamination is expressed as a percentage of wells con-
tensive areas of Precambrian high metamorphic rocks and taminated, these two figures are different. The reason is
granites with widespread sulphide mineralisation. The east- that field-kits results are not 100 percent accurate and for
ern portion of the Indian Platform also includes important many locations samples collected for laboratory test are
Rajmahal coalfield. Because of their position close to where not adequate. Moreover, none of the above methods cov-
the Ganges enters Bangladesh, some authors have sug- ered all the districts. Therefore, a combination of field and
gested that they may be the primary source of arsenic in laboratory test results would give better picture of the ex-
the Bengal alluvium (BGS, 1999).
tent of groundwater arsenic contamination in Bangladesh.
Until 1998, a total of 31,651 water samples were tested by
field and laboratory tests by different organizations. Out
of these, 30,742 were collected from shallow wells (<200
m) and 909 from deep wells (>200 m). It has been found
that 7,942 samples out of the 30,742 from shallow wells
Arsenic Contamination Scenario in Groundwater
Environment of Bangladesh
Spatial Extent of Arsenic Contamination
After DPHE addressed the groundwater arsenic con- and 34 samples out of the 909 from deep wells are con-
tamination problem in Bangladesh in 1993, DPHE itself taminated with the percentages 25.8 and 4, respectively.
and many other government and non-government organi- The arsenic contaminated districts of Bangladesh are
zations, such as Grameen Bank (GB), Non-Government shown in Figure 1. Figure 2 shows the total number of
Organization (NGO) Forum, Dhaka Community Hospital tests performed in each district. Figure 2 will help to as-
(
DCH), School of Environmental Studies (SOES) of sess the representative of the data presented in Figure 1.
Jadavpur University, Bangladesh University of Engineer- From Figure 1, it is apparent that all the surveyed districts
ing and Technology (BUET), Bangladesh Council for Sci- (61 out of 64) show the presence of arsenic contamina-
entific and Industrial Research (BCSIR), NRECA (a US tion. However, nine contaminated districts out of 61 show
consulting firm working for Rural Electrification Board of that a very limited percentage (<1%) of wells are con-
Bangladesh), DANIDA (Official Danish Aid Agency), taminated. Three districts (i.e., Rangamati, Khagrachhari,
Bangladesh Rural Advance Committee (BRAC), and Brit- and Bandarban) were not surveyed by any organization.
ish Geological Survey (BGS), started working on the One reason may be that these three districts are mainly
groundwater arsenic contamination issue. For every orga- hilly areas, with 8.73 percent of the total area of
nization the first job was to identify the arsenic contami- Bangladesh and only 0.92 percent of the total population.
nated wells. According to the World Health Organization Another reason may be that no primary symptoms of ar-
(
WHO), the safe limit of arsenic in drinking water is 0.01 senic patient were found there. Similarly, out of 465 thanas
mg/L. However, WHO set the maximum permissible limit of the surveyed 61 districts, 54 were not surveyed at all by
of arsenic in drinking water for Bangladesh and India as any organization. Thanas is a small administrative unit of
0
.05 mg/L. Sophisticated laboratory facilities are required Bangladesh, which is a sub-division of a district. In each
to accurately detect arsenic in groundwater. Unfortunately, thana there is a police station. That is why sometimes it is
very limited number of these facilities are available in called a “Police Station.” In Bangladesh, there are 64 dis-
Bangladesh. Moreover, laboratory method of arsenic de- tricts and 490 thanas. Moreover, the number of samples
tection is expensive and time consuming. Therefore, many taken from each district is not uniform (Figure 2), which
organizations started groundwater arsenic detection by the suggests that there is a sampling bias of arsenic detection
field-kit method. ‘Field-kit’ is an instrument, which is de- in the country. Out of the 411 surveyed thanas, 270 were
signed to identify the presence of arsenic with Bangladesh found contaminated having arsenic above Bangladesh stan-
standard in drinking water. It is a yes-no instrument that dard (0.05 mg/L). Neglecting all the difficulties, we can
cannot detect absolute concentration of groundwater ar- use Figure 1 to see the extent of groundwater arsenic con-
senic. This method is very simple, but the difficulty is that tamination in Bangladesh. Figure 1 shows that almost
it cannot detect arsenic with reliability if the concentration the whole of the country is contaminated with arsenic.
is less than 0.2 mg/L. A total of 22,777 water samples The severe problem is in the southern (coastal area) and
IWRA, Water International, Volume 26, Number 3, September 2001

Extent and Severity of Groundwater Arsenic Contamination in Bangladesh
373
Figure 1. Groundwater arsenic contamination in different districts of
Bangladesh based on compilation of field and laboratory test data
Figure 2. Districts of Bangladesh showing surveyed and total number
of thanas and total numbers of tests performed for groundwater ar-
senic investigation (Source: BGS, 1999).
(
Source: BGS, 1999).
northeast parts of the country. Table 2 shows ranges of veyed districts were contaminated with concentration of
contamination and their respective percentages of area > 0.05 mg/L, whereas Figure 4 shows seven completely
and population under contamination.
safe districts (i.e., Panchagarh, Thakurgaon, Dinajpur,
The badly affected districts are Brahmanbaria, Comilla, Naogaon, Moulabibazar, Patuakhali, and Cox’s Bazar), and
Feni, Narayanganj, Sariatpur, Narail, Satkhira, and seven districts (i.e., Nilphamari, Lalmonirhat, Gaibanda,
Nawabganj. The disastrous situation is in the districts of Joypurhat, Dhaka, Barguna, and Bhola) were over the
Laksmipur, Noakhali, Madaripur and Chandpur (Figure 1). WHO safety limit but under the maximum permissible limit.
The Ganges, Megna, and Atri Floodplains, the tidal re- Three no-surveyed districts of combined analysis
gions and the coastal plains are the major physiographic (Khagrachhari, Rangamati, and Bandarban) were found
regions vulnerable to arsenic contamination (Figure 3).
contamination free by the SOES-DCH survey. Undoubt-
In April 2000, SOES and DCH jointly published a re- edly, the SOES-DCH survey gives more accurate results
port on Bangladesh groundwater arsenic contamination
(
SOES-DCH, 2000), which shows figures different from
Table 2. Percentage of Arsenic Contamination and Their Respective
Percentage of Area and Population Under Contamination
those in the BGS report. According to SOES-DCH (2000),
up to February 2000, 22,003 tubewell water samples were
analyzed in the laboratory and it was found that in 73.34
percent and 53.47 percent samples the arsenic concentra-
tions were above the WHO and Bangladesh standards,
respectively. SOES-DCH (2000) also found that out of
the 64 surveyed districts, in 54 districts arsenic in ground-
water was above 0.01 mg/L and in 47 districts above 0.05
mg/L. Figure 4 shows arsenic contaminated districts ac-
cording to the SOES-DCH survey. The main difference
between the combined analysis (Figure 1) and the SOES-
DCH survey (Figure 4) is that Figure 1 shows all 61 sur-
Percentage
of Wells
Contaminated
Number of
Districts
Percentage
of Area
Percentage
of Population
<
1
2
1
9
30
18
4
15.85
42.81
27.25
5.36
17.00
46.39
29.42
6.27
~ 25
6 ~ 50
50
>
Unknown
(not surveyed)
3
8.73
0.92
Total
64
100.00
100.00
IWRA, Water International, Volume 26, Number 3, September 2001

374
M.A. Fazal, T. Kawachi, and E. Ichion
Figure 3. Different physiographic units of Bangladesh (after FAO,
988).
Figure 4. Groundwater arsenic contamination in different districts of
Bangladesh (after SOES-DCH, 2000).
1
than field-tests, but has a shortcoming: the samples ana- 41 districts of Bangladesh. Some 14 percent of those were
lyzed are still insufficient in number. Another important taken from wells deeper than 200 meters. They found that
matter is that though SOES-DCH surveyed all 64 districts only about 1 percent of the deep well samples was con-
out of the total 490 thanas, they covered only 222 thanas. taminated above the Bangladesh standard. This is con-
Therefore, if they would cover all the thanas, there is a trasted with 41 perent contaminated wells in the shallower
possibility of increasing number of districts contaminated aquifers. Most of the shallow wells are between 10 m and
by arsenic. Another limitation of SOES-DCH survey is 70 m deep (BGS, 1999).
that their samples are biased as they first identified ar-
The SOES-DCH found similar results. They analyzed
senic patients and then analyzed tubewells water used by arsenic from 15,969 tubewells of 6.4 m to 400 m deep
those arsenic patients. However, there may be a doubt over 47 arsenic affected districts. Their results show that
whether 61 or 47 districts out of 64 are contaminated, while around the depth of 15-20 m there is an increase of ar-
there is no doubt that the country is facing with sever senic concentration and then with increasing depth the
groundwater arsenic problem. To get a clear and accurate arsenic concentration decreases (SOES-DCH, 2000).
picture of groundwater arsenic contamination, a coordi-
nated survey of all drinking water wells and some sampled Population Exposed to Arsenic Contamination
irrigation wells throughout the country is necessary. Ad-
The BGS report states that the probable number
equate numbers of samples should be collected without of people exposed to arsenic concentrations above the
any bias and they should be analyzed accurately in the Bangladesh standard (0.05 mg/l) is about 21 million. This
laboratory. Mitigation of arsenic contamination depends number would be roughly doubled if the WHO guideline
on accurate identification of the contaminated wells, but value of 0.01 mg/l were adopted as a standard (BGS, 1999).
most of the organizations are not strictly following the ap- On the other hand, the SOES-DCH (2000) report shows
propriate identification procedure.
that these numbers are 25 million and 52 million out of 85
million people in 43 districts, respectively. Therefore, if
we consider all 64 districts of the country, the population
exposed to arsenic concentrations above the Bangladesh
Depth-dependent Distribution of Arsenic
Contamination
The BGS tested 2,022 tubewells water samples from standard may be as much as around 40 million. However,
IWRA, Water International, Volume 26, Number 3, September 2001

Extent and Severity of Groundwater Arsenic Contamination in Bangladesh
375
to get a more accurate figure, it is first necessary to iden- survey. The presence of high-level arsenic was detected
tify the accurate number of drinking tubewells along with in 53.47 percent of the water samples, 83.15 percent of
the degree of contamination. For example, SOES-DCH the hair samples, 93.77 percent of the nail samples, and
on the basis of their random survey results estimated that 95.11 percent of the urine samples. Of the total, 20.6 per-
3
.5 million drinking tubewells were prevailing in the coun- cent had identified skin lesions (SOES-DCH, 2000). Alto-
try (SOES-DCH, 2000). But just after a few months, DCH gether, some thousands of arsenic patients and 40 deaths
deduced from the survey results for 500 villages that there due to arsenic-related diseases were identified by the
was a possibility of having 11 million drinking tubewells in SOES-DCH survey only for 241 affected villages. There
the country (DCH, 2000).
are 86,000 villages in the country out of which at least
5,000 may be arsenic affected. In the past it was as-
sumed that the symptoms of arsenic toxicity may take eight
2
Arsenic-related Health Hazards
Skin diseases are the common effects of arsenic poi- to 14 years to be manifested in human body after the pa-
soning. The toxic effect of arsenic species depends mainly tient starts drinking arsenic contaminated water (DCH,
on their chemical form, route of entry, age, sex, doses, and 1998), but the SOES-DCH survey revealed arsenic symp-
duration of exposure. A number of skin lesions have been toms in the body of children ranging from four to seven
attributed to chronic exposure to arsenic compounds. Sym- years old also. The percentage of identified arsenic pa-
metric hyperkeratosis of the palms and soles is a charac- tients seems to be higher than the national average, since
teristic finding after long-term ingestion of inorganic arsenic the selected villages were biased towards more affected
in drinking water. Hyper pigmentation (melanosis) of the areas. But the true situation may be different; as only a
skin is commonly encountered and occurs throughout the small percentage of the true patients in the affected areas
body. Melanosis is not always associated with keratosis, were identified due to many social constraints. Another
but keratosis is always associated with melanosis. Mel- detailed survey of DCH which covered 500 arsenic af-
anosis is also observed in tounge and buccal mucus mem- fected villages shows that 52.17 percent tubewells are
brane (DCH, 1998). Other effects of arsenic are: 1) liver contaminated, 56.15 percent of the total population (of
enlargement and cirrhosis of the liver; 2) myocardial de- affected 500 villages) is at risk, and only 0.28 percent of
generation and cardiac failure; 3) peripheral neurophathy the total population is identified as arsenic patients (DCH,
affecting primary sensory function; 4) diabetics mellitus 2000). The above findings reveal a disastrous situation
and goiter; and 5) skin cancers. Three types of skin can- regarding arsenic pollution in Bangladesh. Table 3 shows
cers are observed: Bowen’s disease, Basal cell carcinoma, the latest statistics regarding groundwater arsenic con-
and Squamous cell carcinoma. These cancers are fre- tamination in Bangladesh.
quently multiple in origins and develop primarily from ar-
senical keratosis (DCH, 1998). In Bangladesh, the majority
Sources and Causes of Arsenic Contamination
of the patients are in the initial and middle stages.
By February 2000, the water samples from 22,003 Sources of Arsenic Contamination in Bangladesh
hand tubewells, around 11,000 randomly selected hairs,
In different countries the potential source of arsenic
nail, urine, and skin-scale samples from 1,063 affected vil- contamination is different. For arsenic contamination in
lages were analyzed in laboratory under the SOES-DCH Bangladesh, initially, several anthropogenic sources were
Table 3. Latest Statistics of Arsenic Contamination with Affected Areas and Population in Bangladesh
Parameter
Total area of Bangladesh
Total population of Bangladesh
Total number of districts of Bangladesh
Number of districts surveyed for investigation of
arsenic contamination
Number of districts having arsneic above maximum
permissible limit
Area of affected districts
BGS (1999)
SOES-DCH (2000)
2
147,570 km *
129.6 million*
64*
2
147,570 km *
129.6 million*
64*
61
61
64
47
2
2
134,275 km
112,407 km
Population of affected districts
128.4 million
465
411
270
80.1 million
93.5 million
357
222
147
46.2 million
Total number of thanas of affected districts
Number of thanas of affected districts surveyed
Number of thanas having arsenic >0.05 mg/L
Area of these thanas having arsenic >0.05 mg/L
Population of exposed to arsenic contamination
(
Population who drink water with arsenic >0.05 mg/L)
21 million
25 million**
*
= BBS (1998) and ** = estimated for 43 districts of Bangladesh.
IWRA, Water International, Volume 26, Number 3, September 2001

376
M.A. Fazal, T. Kawachi, and E. Ichion
considered, such as: 1) use of fertilizers, pesticides, insec- 1960s and rapidly expanded in the early 1980s. At first
ticides, and herbicides containing arsenic; 2) use of ar- DTW irrigation became popular in the country because
senic compounds as preservatives in wooden electric poles the government of Bangladesh (GOB) subsidized farmers
of Rural Electrification Board; 3) tubewell filters coated to purchase DTWs, but under the privatization policy of
with arsenic compound; 4) industrial waste disposal; and the government and according to the suggestion of the
5
) enhanced leaching beneath irrigated lands (BGS, 1999). World Bank since 1991, the GOB stopped giving loans to
Gradually, all these anthropogenic sources were rejected the farmers. As a result, DTW irrigation development be-
based on the field observations. Finally, it was recognized came stagnant. Since then, STWs have become popular,
that the source of arsenic is in the geological deposits.
mainly due to their low cost and due to the withdrawal of
rules and regulations of tubewell installation by the GOB
under the new privatization policy. Only during the irriga-
Causes of Arsenic Contamination in Bangladesh
Two hypotheses are prevailing to describe the cause tion season between 1995/1996 season and the 1996/1997
mobilization) of arsenic into groundwater of Bangladesh. season, the area under STWs increased by 7.7 percent.
These are: a) Pyrite Oxidation and b) Oxy-hydroxide Re- The irrigated areas under DTWs, LLPs (low lift pumps),
(
duction.
and the traditional system decreased by 11.7, 1.2, and 20
percent, respectively. As a result, the overall area under
the minor irrigation increased by 1 percent. During this
Pyrite Oxidation Hypothesis
Arsenic is assumed to be present in certain sulphide period, the area under groundwater irrigation increased
minerals (pyrites) that are deposited within the aquifer by 3.1 percent, while the area under surface water irriga-
sediments. Due to the lowering of water table below de- tion decreased by 3.8 percent. The contribution of ground-
posits, arseno-pyrite oxidized in the vadose zone releases water to total irrigated area increased from 41 percent in
arsenic as arsenic adsorbed on iron hydroxide. During the 1982/1983 to 71 percent in 1996/1997 with an increasing
subsequence recharge period, iron hydroxide releases ar- tendency in each year, while the contribution of surface
senic into groundwater. According to this hypothesis, the water steadily declined from 59 to 29 percent over the
origin of arsenic rich groundwater is man-made, which is same period (NMIDP, 1998). The growth of irrigation area
a recent phenomenon. The mechanism is illustrated in Fig- since 1983 in terms of irrigation technologies is shown in
ure 5.
The intensive irrigation development in the country
Figure 6.
supports the above hypothesis. Irrigation development in
Bangladesh using DTWs and STWs started in the early
Figure 6. Growth in irrigated areas of Bangladesh since 1983 (after
NMIDP, 1998).
The lack of prior reported arsenic patients before irri-
gation development based on groundwater extraction in
the country also supports the pyrite oxidation hypothesis,
although a significant number of people were using ground-
water through tubewells or dug wells as a drinking water
source at that time. Until only two years ago, groundwaters
in Rangpur, Jamalpur, and Bogra districts had been con-
sidered as safe, but now they are not only contaminated,
but also these areas contain many identified arsenic pa-
tients (SOES-DCH, 2000).
Figure 5. Aerobic condition in groundwater around a tubewell (after
Oxy-hydroxide Reduction Hypothesis
Arsenic is assumed to be present in alluvial sediments
Karim et al., 1997).
IWRA, Water International, Volume 26, Number 3, September 2001

Extent and Severity of Groundwater Arsenic Contamination in Bangladesh
377
with high concentrations in sand grains as a coating of 2000b) noted that the correlation between extractable iron
iron hydroxide. The sediments were deposited in valleys and arsenic does not necessarily imply the adsorption (oxy-
eroded in the delta when the stream base level was low- hydroxide reduction) hypothesis, and questions were put
ered due to the drop in sea level during the last glacial forward by Adel (2000) for the availability of pH, Eh data.
advance. The organic matter deposited with the sediments Thus, the above two relationships became confusing. On
reduces the arsenic bearing iron hydroxide and releases the other hand, for the third correlation BGS found a sig-
arsenic into groundwater. According to this hypothesis, nificant negative relationship, which contradicts acceptance
the origin of arsenic rich groundwater is due to a natural of oxy-hydroxide reduction hypothesis. A detail analysis
process, and it seems that the arsenic in groundwater has of the courses of groundwater contamination with arsenic
been present for thousands of years without being flushed can be found in another paper by the authors in this issue
from the delta.
The Oxy-hydroxide Reduction hypothesis to de-
of Water International.
scribe the mobilization of arsenic from the source to the
groundwater for Bangladesh basin was first proposed by
Nickson et al. (1998).
Remedies of Arsenic Problem
Treatment for Arsenicosis
Unfortunately there is no specific treatment for chronic
arsenicosis. Stopping further intake of arsenic contami-
nated water and drinking arsenic-free water improves the
cases. A recent report of DCH (2000) states that chronic
Investigations of Arsenic
Mobilization Hypotheses
Although primary investigations regarding rapid irri- arsenicosis cannot be cured, but the symptoms are re-
gation development and rate of water abstraction support versible up to certain point if a patient discontinues ingest-
the pyrite oxidation hypothesis, BGS rejected it based on ing contaminated water. If a patient crosses this threshold,
some space-dependent correlations. The BGS investigated he/she still needs medical assistance to save his/her life.
five correlations: 1) the correlation between gross water For instance, amputation may save the life of a patient
abstraction and percent of wells contaminated; 2) the cor- suffering from gangrene. Palliative drugs may also be ad-
relation between maximum water level below ground sur- ministered along with micronutrient supplement (DCH,
face and percent of wells contaminated; 3) the correlation 2000).
between aquifer transmissivity and percent of wells con-
taminated; 4) the correlation between sulphate concentra- Watershed Management
tion and arsenic concentration; and 5) the correlation
For a proper remedy of the problem, at first all of the
between potential recharge and percent of wells contami- contaminated tubewells should be identified accurately, and
nated, to see the validity of the pyrite oxidation hypothesis. then the proper cause(s) of the contamination should be
They found no significant but negative trends of relation- investigated. The over-abstraction of groundwater should
ships for correlations 1 to 4 (above) and no significant but be regulated. In highly affected areas where most tubewells
positive trend of relationship for Correlation 5 (BGS, 1999). are found contaminated, the immediate solution may be to
Therefore, they rejected pyrite oxidation hypothesis. How- share safe tubewells. If that is not possible, water from
ever, a recent investigation by Fazal et al., (in press) points contaminated tubewells should be used after filtering to
out that due to the errors in the key parameter employed reduce concentration of arsenic. In the contaminated area,
BGS results of percentage of wells contaminated, are not immediate installation of deep tubewell may be an alterna-
reliable to make any conclusion about pyrite oxidation. tive, as most of the deep aquifers are arsenic free. It is
Moreover, the space-dependent relationships among dif- better to use alternative source of water, such as pond
ferent hydrogeological parameters for the heterogeneous water with slow sand filtration and harvested rainwater, if
aquifer system are not valid to represent time-dependent possible. If no other options exist, it is urgent to shift to
phenomenon. Therefore, conclusions made by the BGS surface water use or construct arsenic treatment plants.
about this issue are not valid.
In order to support oxy-hydroxide reduction hypoth-
Conclusions
esis, the BGS investigated three correlations: 1) the corre-
lation between extractable iron concentration and arsenic
An investigation was undertaken to analyze the latest
concentration; 2) the correlation between arsenic concen- statistics regarding arsenic contamination of groundwater
tration and the reducing conditions (pH-Eh); and 3) the in Bangladesh. Attempt was made to provide an overview
correlation between arsenic concentration and depth of of the extent and severity of the problem, its probable
contamination. For the first and second correlations, they causes, effects and remedies. The facts and urgent needs
found significant positive relationships, and therefore they to be emphasized could be summarized as follows:
accepted oxy-hydroxide reduction hypothesis (BGS, 1999).
However, regarding the appropriateness of considering • Regarding arsenic pollution, Bangladesh, with 25 to 40
extractable iron concentration, Bridge and Husain (2000a;
million people exposed to poisoning, is the most vulner-
IWRA, Water International, Volume 26, Number 3, September 2001

378
M.A. Fazal, T. Kawachi, and E. Ichion
able country in the world. Out of 64 districts of the
Discussions open until March 1, 2002.
country, 47 to 61 districts have arsenic content above
the WHO recommended maximum permissible limit
of 0.05 mg/L.
References
•
•
Thousands of people are suffering from arsenic-re- Adel, M.M., 2000. “Arsenification: Searching for an Alternative
lated diseases ranging from melanosis to skin cancers Theory.” Daily Star of Bangladesh. April 2000.
and gangrene, and many even died. Unfortunately, there Akram, S. 1997. “Arsenic Problem.” Daily Sangbad of
is no specific treatment for arsenicosis. Bangladesh. August, 1997.
Two hypotheses, pyrite oxidation and oxy-hydroxide Anwarul Islam, A.S., M.N. Haque, and M.H. Mazumder. 1998.
reduction, are prevailing in Bangladesh to describe the
cause of arsenic contamination. However, until now
none of them has been studied thoroughly with accu- BBS (Bangladesh Bureau of Statistics). 1998. 1997 Statistical
“Arsenic Problem and its Investigations.” Engineering News
(Engineers Institution, Bangladesh) No. 5: 16–20.
th
rate field data. The verdict is still out rather to support
one hypothesis over the other.
Arsenic contamination in Bangladesh is a serious na- Begum, Z.R. and M.M. Karim. 2000. “Arsenic Groundwater Con-
Yearbook of Bangladesh. 18 edition. Dhaka, Bangladesh:
Statistics Division, Ministry of Planning.
•
tional problem. To control and eradicate the ravages of
the contamination, the exact cause(s) of contamina-
tion and its mobilization mechanism should be identi-
fied. Then a remedial action plan should be made with
tamination of Bangladesh: Community Participation in
rd
Groundwater Resources Management.” Proceedings of 93
Annual Meeting of Air and Waste Management Associa-
tion: Salt Lake, Utah, USA 18-22 June 2000: 1–10.
participation of experts in relevant fields and commu- Bridge, T.E. and M.T. Husain. 1999a. “When Did the Groundwa-
nity representatives.
ter Arsenic Poisoning in Bangladesh Begin?” News From
Bangladesh.
Bridge, T.E. and M.T. Husain, 1999b. “The Increased Draw Down
and Recharge in Groundwater Aquifers and their Relation-
ship to the Arsenic Problem in Bangladesh.” http://
www.dainichi-consul.co.jp/english/arsenic/arsarticles.html.
Bridge, T.E. and M.T. Husain. 2000a. “Clean Healthy Water for
Bangladesh- An Emergency Supply is Desperately Needed
to Protect the People from the Arsenic Disaster.”
http://www.dainichi-consul.co.jp/english/arsenic/
arsarticles.html.
Acknowledgement
The authors would like to thank the Japan Society for
the Promotion of Science (JSPS) for supporting this re-
search from the post-doctoral research fund.
About the Authors
Md. Abul Fazal is a Scientific Officer at Bangladesh
Agricultural Research Institute. At present, he is working Bridge, T.E. and M.T. Husain. 2000b. “Groundwater Arsenic
on Bangladesh groundwater arsenic contamination issue
as a post-doctoral research fellow of the Japan Society
for the Promotion of Science (JSPS) in Kyoto University.
Dr. Fazal received his M.Sc. in Hydrology from National
Poisoning and a Solution to the Arsenic Disaster in
Bangladesh.” Presented at the ICBEN conference at Dhaka,
Bangladesh, 14 January 2000. Daily Star of Bangladesh. 21
January 2000.
University of Ireland, in 1993 and Ph.D. from Kyoto Uni- British Geological Survey (BGS). 1999. “Groundwater Studies
versity, Japan, in 1999. He has been working on the water
resources management with main emphasis on ground-
water engineering since 1988.
Toshihiko Kawachi is a Professor of Water Re-
sources Engineering at Kyoto University, Japan. His main
subjects of research are hydraulic and environmental mod-
for Arsenic Contamination in Bangladesh.” Main Report and
Supplemental Volumes 1–3. Dhaka, Bangladesh and Mott
MacDonald International Ltd., United Kingdom: Government
of the Peoples Republic of Bangladesh, Ministry of Local
Government, Rural Development and Cooperatives, Depart-
ment of Public Health Engineering.
eling, and optimum management and control of water re- Dhaka Community Hospital (DCH). 1998. Arsenicosis in
sources systems. Finite element, finite volume, fuzzy Bangladesh. Dhaka, Bangladesh: 1–46.
reasoning, neural network, genetic algorithm and GIS are Dhaka Community Hospital (DCH). 2000. Arsenic in Bangladesh:
employed for such hydro-environmental modeling. Pro-
fessor Kawachi published more than 100 research papers
in different journals. Also, he serves as a peer reviewer Fazal, M.A., T. Kawachi, and E. Ichion. 2001. “Validity of the
Report on the 500-Village Rapid Assessment Project., Dhaka,
Bangladesh: 1–48.
for different scientific journals.
Eiji Ichion has been a Lecturer of Ecological Sys-
tems Engineering at Ishikawa Agricultural College,
Latest Research Findings on Causes of Groundwater Ar-
senic Contamination in Bangladesh.” Water International
(in press).
Ishikawa, Japan, since 1998. Before 1998 he worked for Hossain, A., M.F. Rabbi, A.R. Abid and S. Sadek. 2000. “Ar-
1
3 years as a consultant engineer in Nihon-koei Consult-
senic Problem in Groundwater, a Growing Threat to Public
Health in Bangladesh: An Overall Perspective and Manage-
ment Modelling Approach.” K. Sato and Y. Iwasa, eds. Pro-
ing Co. Ltd., Japan. His major field of research is water
resources management.
IWRA, Water International, Volume 26, Number 3, September 2001

Extent and Severity of Groundwater Arsenic Contamination in Bangladesh
379
ceedings of the International Symposium 2000 on Ground-
water. 7–10 May 2000: Saitama, Japan.
Husain, M.T. 2000. “Oxy-hydroxide Reduction and Agrochemi- Nickson, R., J. McArther, W. Burgess, K.M. Ahmed, P.
Bangladesh.” Journal of Environmental Chemistry 7, No. 4:
783–792.
cal Hypothesis: Myth or Reality?” http://www.dainichi-
consul.co.jp/english/arsenic/arsarticles.html.
Khalequzzaman, M. 1999. “Comments on Arsenic Study in Nickson, R.T., J.M. McArther, P. Ravenscroft, W.G. Burgess,
Ravenscroft and M. Rahman. 1998. “Arsenic Poisoning of
Bangladesh Groundwater.” Nature 395.
Bangladesh.” Daily Star of Bangladesh. 9 June 1999.
Kamal, M.R. and M.M. Karim. 2000. “GIS Application for Moni-
toring Arsenic Groundwater Contamination Exposures in
Bangladesh.” Dr. K. Sato and Dr. Y. Iwasa, eds. Proceedings
of the International Symposium 2000 on Groundwater. 7 –10
May 2000. Saitama, Japan:.55015060.
and K.M. Ahmed. 1999. “Mechanism of Arsenic Release to
Groundwater, Bangladesh and West Bengal.” Journal of
Applied Geochemistry 15: 403–413.
NMIDP (National Minor Irrigation Development Project). 1998.
National Minor Irrigation Census 1996/97. , Dhaka,
Bangladesh: Sir William Halcrow and Partners Ltd. and DHV
Consultants BV.
Karim, M.M. 2000a. “Arsenic in Groundwater and Health Prob-
lems in Bangladesh.” Journal of Water Research 34, No. 1: SOES-DCH. 2000. “Groundwater Arsenic Contamination in
3
04–310.
Bangladesh.” A. Summary of 239 days field survey from
August 1995 to February 2000, B. Twenty-seven days de-
tailed field survey information from April 1999 to February
2000. School of Environmental Studies, Jadavpur University,
Calcutta 700 032, India and Dhaka Community Hospital,
Dhaka 1217, Bangladesh.
Karim, M.M. 2000b. “Arsenic Exposure Modeling and Risk As-
sessment in Bangladesh using Geographic Information Sys-
tem.” The Second International Health Geographics
Conference. Washington, DC, USA, 17-19 March 2000.
Karim, M.A., Y. Komori, and M. Alam. 1997. “Subsurface Ar-
senic Occurrence and Depth of Contamination in
IWRA, Water International, Volume 26, Number 3, September 2001