Drinking Water Vulnerability to Arsenic Mahottari District

123 Pages·2004·14.77 MB·English

KYMC
KYMC
National Arsenic Steering Committee (Nepal)
Environment and Public Health Organization (Nepal)
The State of Arsenic in Nepal - 2003
B. R. Shrestha (PhD), J. W. Whitney (PhD) and K. B. Shrestha (PhD) (Editors)
January 2004
This document is the output of the project funded by United States Geological Survey (USGS)
through a US Government Public Diplomacy Grant from the US Embassy in Kathmandu.
Reproduction of materials contained in this report is granted to the inclusion of the following acknowledgement:-
“This report was produced by the National Arsenic Steering Committee (Nepal) and Environment and Public
Health Organization (Nepal) undertaking a project funded by USGS through a US Government Public Diplomacy
Grant from the US Embassy in Kathmandu. The opinions, findings, and conclusions or recommendations expressed
herein are those of the Author(s) and do not necessarily reflect those of the USGS or US Embassy”. In cases where
only a map, diagram, data from the report or CD are used, the above acknowledgement may be substituted by a full
citation to the report.
Cover Illustration
A woman pumping water from a tube well in Pipra (Purba) village of Saptari District.
Bibliographic Reference
Shrestha, B. R., Whitney, J. W., and Shrestha, K. B. (Editors), The State of Arsenic in Nepal-2003,
National Arsenic Steering Committee, Environment and Public Health Organization, Kathmandu, Nepal, 126
pages and CD-ROM.
This publication is comprised of a final report and a CD-ROM
ISBN: 99933-895-4-4
© NASC, ENPHO copyright 2004
ii
Project Team
Project Co-ordinator
Roshan R. Shrestha (PhD), Executive Chairman - ENPHO
Team Leader / System Specialist
Bhushan R. Shrestha, PhD
Geostatistician
Kabita B. Shrestha, PhD
Editors
Bhushan R. Shrestha; John W. Whitney, PhD, (USGS) and Kabita B. Shrestha
Maps & spatial data preparation
Keshab Paudel and Archana Pradhan
Data acquisition and data management
Prajwal Shrestha
Programmer
Rabin Shrestha
Office Assistant
Binod Dhungana
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Acknowledgement
We would like to thank Mr. Hari Ram Koirala, Chairman, NASC and Mr. Shree Ram Shrestha, Member Secretary, NASC for their
continuous support during entire project period. We would also like to express our thanks to all members of NASC for their
continuous support by providing useful data and information and valuable suggestions to make this project successful.
We would like to express our sincere thanks to all Task Force members created by NASC to support this project, Mr. Avadh
Kishore Mishra (DWSS), Mr. Madhav Pahari (UNICEF), Ms. Kalawati Pokhrel (RWSSSP), Dr. Ram Bahadur Shah (TU), Mr.
Mohan Singh Khadka (DoI), NRCS and NEWAH/ISET for their continuous support, valuable suggestions and remarks during
whole project period.
We would like to express our thanks to Mr. Hans D. Spruijt, UNICEF for his continuous support on groundwater arsenic studies
in Nepal. We would like to thank Mr. Constance Colding Jones and Mr. Ramesh Acharya from the American Center for facilitating
the public diplomacy grant to conduct this study. We would also like to thank Mr. Michael De Tar, Ms. Katharine Koch and Mr.
Jay Pal Shrestha from the US Embassy for continuing support of arsenic studies in Nepal.
Our special thanks to Mr. Madhav Pahari, Dr. Ram Bahadur Shah, Mr. K.P. Kaphle (DoMG), Mr. Amar Neku (Water Aid), J. Yount
(USGS) and Mr. Nabin Pradhan (Plan Nepal) for their valuable time for reviewing the draft report and providing valuable comments
and suggestions.
We would like to thank Mr. Jaya Shrestha for data entry, Mr. Sushan Prajapati for page layout and graphics, and all field workers
for GPS data collection. Finally, we would like to thank Ms. Arinita Maskey for helping us in data acquisition, Ms. Sunita
Pradhananga for administrative work, and all other ENPHO staffs for supporting this project in different ways.
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Contents
Page
Acknowledgement iv
Contents v
List of Maps vi
Abbreviations vii
Executive Summary viii
1. Introduction 1
(Bhushan R. Shrestha)
2. Sources and occurrences of the arsenic in the environment 1
(John W. Whitney)
3. Arsenic in groundwater in East and South Asia 3
(Nirmal Tandukar, DWSS)
4. Geology, hydrogeology and sedimentology 4
(Suresh D. Shrestha, PhD, TU and Van S. Williams, PhD, USGS)
4.1. Location and extent of area
4.2. Topography and drainage
4.3. Hydrogeology
4.4. Stratigraphy and geomorphology
5. Issues related to groundwater arsenic in Nepal 6
(Roshan R. Shrestha and Anil Pokharel, NEWAH )
5.1. History
5.2. Health effects
5.3. Arsenic mitigation measures undertaken
5.4. Media and arsenic contamination
6. Data and map preparation 11
(Bhushan R. Shrestha and Van S. Williams)
6.1. Integrated database of arsenic tested tube wells
6.2. Preparation of digital spatial data sets
6.3. Map preparation
6.4. Accuracy of spatial data
7. Analysis of arsenic concentration in tube wells in the Terai 17
(Kabita B. Shrestha and Bhushan R. Shrestha)
7.1. Basic statistical analysis of arsenic concentration
7.2. Relation of arsenic concentration with depth of tube well
7.3. Relation of arsenic concentration with age of tube well
7.4. Arsenic exposed population and households
7.5. Spatial analysis of arsenic concentration
7.5.1. Classification of arsenic concentration at VDC level
7.5.2. VDCs vulnerable to arsenic
7.5.3. Mapping of arsenic concentration
7.5.4. VDCs arsenic hotspots
8. Distribution of arsenic in the Terai 93
(Kabita B. Shrestha)
9. Recommendation 99
(Bhushan R. Shrestha, John W. Whitney and Kabita B. Shrestha)
Annex
References
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List of maps
1. Classification of Arsenic Concentration – Banke District 35. Drinking Water Vulnerability to Arsenic – Rautahat District
2. Classification of Arsenic Concentration – Bara District 36. Drinking Water Vulnerability to Arsenic – Rupandehi District
3. Classification of Arsenic Concentration – Bardiya District 37. Drinking Water Vulnerability to Arsenic – Saptari District
4. Classification of Arsenic Concentration – Chitwan District 38. Drinking Water Vulnerability to Arsenic – Sarlahi District
5. Classification of Arsenic Concentration – Dang District 39. Drinking Water Vulnerability to Arsenic – Siraha District
6. Classification of Arsenic Concentration – Dhanusha District 40. Drinking Water Vulnerability to Arsenic – Sunsari District
7. Classification of Arsenic Concentration – Jhapa District 41. Arsenic Concentration Mapping – Banke District
8. Classification of Arsenic Concentration – Kailali District 42. Arsenic Concentration Mapping – Bara District
9. Classification of Arsenic Concentration – Kanchanpur District 43. Arsenic Concentration Mapping – Bardiya District
10. Classification of Arsenic Concentration – Kapilbastu District 44. Arsenic Concentration Mapping – Jhapa District
11. Classification of Arsenic Concentration – Mahottari District 45. Arsenic Concentration Mapping – Kailali District
12. Classification of Arsenic Concentration – Morang District 46. Arsenic Concentration Mapping – Kanchanpur District
13. Classification of Arsenic Concentration – Nawalparasi District 47. Arsenic Concentration Mapping – Kapilbastu District
14. Classification of Arsenic Concentration – Parsa District 48. Arsenic Concentration Mapping – Morang District
15. Classification of Arsenic Concentration – Rautahat District 49. Arsenic Concentration Mapping – Nawalparasi District
16. Classification of Arsenic Concentration – Rupandehi District 50. Arsenic Concentration Mapping – Parsa District
17. Classification of Arsenic Concentration – Saptari District 51. Arsenic Concentration Mapping – Rautahat District
18. Classification of Arsenic Concentration – Sarlahi District 52. Arsenic Concentration Mapping – Rupandehi District
19. Classification of Arsenic Concentration – Siraha District 53. Arsenic Concentration Mapping – Saptari District
20. Classification of Arsenic Concentration – Sunsari District 54. Arsenic Concentration Mapping – Siraha District
21. Drinking Water Vulnerability to Arsenic – Banke District 55. Arsenic Concentration Mapping – Ramgram Municipality
22. Drinking Water Vulnerability to Arsenic – Bara District 56. Arsenic Concentration Mapping – Manari VDC
23. Drinking Water Vulnerability to Arsenic – Bardiya District 57. Arsenic Concentration Mapping – Swathi VDC
24. Drinking Water Vulnerability to Arsenic – Chitwan District 58. Arsenic Concentration Mapping – Tilakpur VDC
25. Drinking Water Vulnerability to Arsenic – Dang District 59. Arsenic Concentration Mapping – Sunwal VDC
26. Drinking Water Vulnerability to Arsenic – Dhanusha District 60. Arsenic Concentration Mapping – Mahendrakot VDC
27. Drinking Water Vulnerability to Arsenic – Jhapa District 61. Arsenic Concentration Mapping – Jahada VDC
28. Drinking Water Vulnerability to Arsenic – Kailali District 62. Arsenic Concentration Mapping – Rampur Khap VDC
29. Drinking Water Vulnerability to Arsenic – Kanchanpur District 63. Arsenic Concentration Mapping – Devdaha VDC
30. Drinking Water Vulnerability to Arsenic – Kapilbastu District 64. Arsenic Concentration Mapping – Sangrampur VDC
31. Drinking Water Vulnerability to Arsenic – Mahottari District 65. Classification of Arsenic Concentration – Terai
32. Drinking Water Vulnerability to Arsenic – Morang District 66. Distribution of Population and Household – Terai
33. Drinking Water Vulnerability to Arsenic – Nawalparasi 67. Proportion of Households using Arsenic tested TW to Total
District HH - Terai
34. Drinking Water Vulnerability to Arsenic – Parsa District 68. Drinking Water Vulnerability to Arsenic – Terai
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Abbreviations
AAN Asia Arsenic Network RWSSSP Rural Water Supply and Sanitation
AAS Atomic Absorption Spectrophotometer Support Program
AIRP Arsenic Iron Removal Plant Std. Standard
As Arsenic TU Tribhuwan University
As S Orpiment TW Tube Well
2 3
AsS Realgar UNICEF United Nations Children’s Fund
BGS British Geological Survey USGS United States Geological Survey
CD Compact Disc UTM Universal Transverse Mercator
CD-ROM Compact Disc- Read Only Memory VDC Village Development Committee
DoI Department of Irrigation WGS84 World Geodetic System of 1984
DoMG Department of Mines and Geology WHO World Health Organization
DPHE Department of Public Health Engineering, µg/l Microgram per liter
Government of the People’s Republic of
Bangladesh
DWSO District Water Supply Office
DWSS Department of Water Supply and
Sewerage
ENPHO Environment and Public Health
Organization
ESRI Environment Science Research Institute
FeAs Lollingite
2
FeAsS Arsenopyrite
FeCl Ferric Chloride
3
GIS Geographic Information System
gm Gram
GPS Global Positioning System
HH Household
HMG His Majesty’s Government
IEC Information, education and
communication
JRCS Japanese Red Cross Society
kg Kilogram
km Kilometer
L/s Liter per second
LGP Local Governance Program
M Meter
MCM Million cubic meter
MFT Main Frontal Thrust
mg Milligram
mg/l Milligram per litre
MIT Massachusetts Institute of Technology
MoE Ministry of Education
MPPW Ministry of Physical Planning and Works
MUTM Modified Universal Transverse Mercator
NA Not available
N.P. Municipality (Nagar Palika)
NaOCl Sodium Hypo Chloride
NASC National Arsenic Steering Committee
NEWAH Nepal Water for Health
NGOs Non Governmental Organizations
NRCS Nepal Red Cross Society
PDDP Participatory District Development
Program
ppb Parts per billion
RONAST Royal Nepal Academy of Science and
Technology
RWSSFDB Rural Water Supply and Sanitation Fund
Development Board
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Executive Summary since 2000 by various methods. Nearly 6% of these tube
wells in the Terai have been recently tested for arsenic. This
The discovery of dangerous levels of arsenic in large report integrates all qualified arsenic test results from these
numbers of ground water tube wells in West Bengal, India organizations, collected through the summer of 2003, into a
during the early 1990’s, followed closely by even higher national arsenic database, which is provided on the CD-
levels of arsenic in even greater numbers of wells in ROM that accompanies this report.
Bangladesh in the mid to late1990’s, has raised the specter
of a potential environmental disaster in South Asia. The The national database in 2003 consists of 18,635 arsenic-
World Health Organization estimates that 40-60 million people tested tube wells. Arsenic distribution and summary
are at risk from drinking arsenic-contaminated water in statistics for each district and VDC (village development
Bangladesh and West Bengal, and that this health risk also committee) are shown on maps and tables, and are included
may extend into southern Nepal. on the accompanying CD-ROM. The majority of tube wells,
76.3%, are below the WHO Guideline of 10 ppb.
The first Nepalese studies on arsenic in groundwater were Approximately 7.4% of all tube wells tested higher than the
carried out in 1999 by the Department of Water Supply and Nepal Interim Standard of 50 ppb of arsenic concentration
Sewerage, and the World Health Organization, and in 2000 and 16.3% of tube wells contained 11-50 ppb of arsenic
by the Nepal Red Cross Society and the Japanese Red Cross concentration. Thus, 23.7% of tube wells in the Terai are
Society. Both studies provided evidence of arsenic above WHO Guideline. The percentage of wells contaminated
contamination in Terai region of southern Nepal. above 50 ppb varies at district level from 0% in Dang,
Furthermore, an initial health survey in 2001-2002 found Chitwan, and Sunsari to 25.7% in Nawalparasi. Over half of
evidence of arsenic-related dermatosis and elevated amounts the arsenic-tested tube wells in Rautahat and nearly half of
of arsenic in human hair and nail samples in four districts those tested in Nawalparasi contain more than 10 ppb of
where tube well drinking water contained arsenic above 50 arsenic. The highest concentrations of arsenic (up to 2,620
ppb (parts per billion). This initial evidence of arsenic ppb) were measured in Devedaha VDC of Rupandehi district,
contamination and associated health effects led to the near the border with Nawalparasi.
creation of the National Arsenic Steering Committee (NASC)
to help coordinate efforts by government and non- Most of the tube wells with high arsenic values are less than
government agencies to address the potential problems of 50 m deep, and the majority of tube wells deeper than 50 m
arsenic contamination in the rapidly growing region of have arsenic values below 50 ppb. The highest percentage
southern Nepal. of contaminated wells is found from 11 to 30 m deep. In that
depth range 11% of arsenic-tested tube wells were above
Approximately 500,000 shallow tube wells provide water to Nepal Interim Standard; 32% of tube wells were above WHO
about 11 million people, nearly half of the national Guideline; and 68% of the wells tested were below the WHO
population, in the agriculturally important Terai region. Guideline. A very low correlation was found between the
Ninety percent of the people in the Terai use groundwater level of arsenic of a well and the age of the well.
as their primary source for drinking water. Providing clean
drinking water and developing groundwater resources for Classes of arsenic vulnerability are defined and presented
agriculture are significant challenges for government and on maps at the district level based on the percentage of
non-government organizations, and the issue of arsenic arsenic tested tube wells exceeding the WHO Guideline. Four
contamination must now be evaluated by all agencies and classes of vulnerability are defined. Low vulnerability to
organizations that provide drinking water. Nearly all water arsenic: VDCs where the percentage of tube wells above
organizations have been testing wells in their project areas WHO guideline is zero (0). In these VDCs, all arsenic tested
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tube wells contain 0-10 ppb of arsenic. Moderate vulnerability district, Chitwan, with low vulnerability to arsenic. However,
to arsenic: VDCs where 1-25% of tested tube wells exceed this classification has high uncertainty, because only 1% of
the WHO Guideline for arsenic. Moderately high total households of the district were using arsenic-tested
vulnerability to arsenic: VDCs where 26-50% of tested tube tube wells.
wells exceed the WHO Guideline. High vulnerability to
arsenic: VDCs where over 50% of arsenic-tested tube wells In terms of population exposed to potential arsenic-related
exceed the WHO Guideline. health risks, the 2003 arsenic database indicates that 69,126
people (5.4%) were drinking water above the Nepal Interim
Among the 1,050 arsenic-tested VDCs, only 20 VDCs had standard at the time of testing; 44% of those people live in
more than 100 tube wells that were tested for arsenic by Nawalparasi district, 21% in Rautahat, and the rest, or 34%,
2003. Moreover, there were only five VDCs, in Nawalparasi are distributed among the other districts. The population in
district, that contained more than 200 arsenic-tested tube the Terai estimated to be drinking water that exceeds the
wells. Although 60% of VDCs have low vulnerability, nearly WHO Guideline is 272,626 (21.3%). These statistics will likely
74% of those VDCs have a high uncertainty for that assigned change in the future, because arsenic testing has not yet
vulnerability level, because of a very low number of wells taken place in 345 VDCs - 25% of the total VDCs - in the
that were tested in those VDCs. In order to account for Terai.
VDCs with low levels of arsenic testing, a level of uncertainty
was characterized to help describe the confidence that Recommendations to improve the national arsenic database
accompanies the level of vulnerability assigned to each VDC.
The uncertainty is based on the proportion of household in The sources of arsenic in the ground water are believed to
a VDC that is using a tested tube well. be of geologic origin. However, the processes that
concentrate arsenic to environmentally dangerous levels in
Among the 20 Terai districts only one district, Rautahat, is the shallow aquifers are poorly understood. It is not yet
characterized with high vulnerability to arsenic. The clear whether or not contamination is entirely natural or is
uncertainty level is also low for this district. This indicates accelerated by human activities. Because the mechanisms
that more than 50% of arsenic tested tube wells were above of arsenic contamination are not yet defined, it is important
the WHO Guideline, and that the percentage of households to continue arsenic testing of wells in the Terai and, because
using arsenic tested tube wells is 26-50%. Two districts, arsenic levels may increase over time, wells with arsenic
Nawalparasi and Kailali, have been classified as having levels that exceed the WHO Guideline should be monitored
moderately high vulnerability to arsenic; however, their at some regular interval. Areas of anomalously high arsenic
uncertainty levels are different. Nawalparasi has medium concentrations found in the database should be tested
uncertainty, and Kailali has high uncertainty. Therefore, further to define the areal extent of the “arsenic hotspot”,
although both districts have moderately high vulnerability and mitigation efforts should be introduced to these areas
to arsenic, Nawalparasi district has more arsenic-exposed of concern. Health organizations should initially focus on
households than Kailali. these arsenic hotspots to identify individuals in need of
medical attention.
The majority of districts in the Terai have been classified as
moderate vulnerability to arsenic. However, the level of Standard procedures need to be created for continued field
uncertainty is different in these districts. Among 16 districts kit testing, laboratory analyses, and data maintenance. Most
classified with moderate vulnerability to arsenic, 9 districts important is the inclusion of GPS well location data with
have high uncertainty, 4 districts have medium uncertainty arsenic tests. As more new field test kits become available,
and 3 districts have low uncertainty. There is only one they should be tested and verified with laboratory results.
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