NSU Presentation 7Dec 2009 Alt
Transcript of NSU Presentation 7Dec 2009 Alt
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 1/39
Arsenic in tubewell water and
approaches for sustainablemitigation
Md. Jakariya
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 2/39
1.Global and national extent of arsenic
contamination
2. Challenges to mitigate the arsenic problem
3. Approaches for sustainable mitigation
papers
Presentation Outline
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 3/39
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 4/39
Arsenic in the Indus-Ganges-Meghna-Brahmaputra River System
Bangladesh
Primary sources of arsenic:
Himalayan and surroundingregion
Arsenic is transportedthrough the sediments bythe river Ganges-Indus (andtheir tributaries) up to the
Bengal/Indus Delta. India
Nepal
Himalaya
Pakistan
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 5/39
•There are 8-10 million wells;
•Approximately 30% exceeds
BDWS;
•>50% exceeds WHO guidelinevalue;
•25-30 million people are
exposed to arsenic poisoning;
•Mitigation and patient
identification are limited
considering the magnitude of
the problem.0
10
20
30
40
50
% o f T e s t e d W e l l s
< 0.01 0.01-0.05 > 0.05
Arsenic Concentrations (mg/L)
29.19 30.15
21.3612.93
65.16
23.5929.12
0
20
40
60
80
100
B A M W
S P ( 1 9 0 )
U N I C E F ( 4
5 )
W o r l d V i s
i o n ( 1 3 )
W P P ( 1
5 )
D A N I D A
( 8 )
A A N ( 0 1 )
T o t a l ( 2 7
2 )
Organizaion (No of Upazila)
% o f T e s t e d T W
Arsenic in the groundwater of the
Bengal Delta Plain (BDP)
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 6/39
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 7/39
Approaches for sustainable mitigation
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 8/39
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 9/39
Assessment of the effectiveness of field test
kit results (n=12,532) and its validation
(k=0.91, p<0.01)(k=0.92, p<0.01)Kappa test (k)
0.910.92Specificity
0.980.99Sensitivity
5.12.3False Negative (%)
3.64.4False Positive (%)
7464Prevalence (%)
WHO drinkingwater guideline
(10 µg/L)
BWDS level(50 µg/L)
Indices for validation of the
field kit results
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 10/39
Comparison between Merck field kit and
laboratory (AAS) results
Average 87%Average 91%12,532 (100)Total
99991253 (10)>500
99906141 (49)100-499
9870877 (7)50-99
8687 501 (4)25-49
4798376 (3)10-24
95993384 (27)0-9.9
10 µg/L level50 µg/L level
Percentage of TWs detected
correctly (%)
Total number
of TWsscreened*
Concentration
range (in µg/L)
*The values in parentheses represent the percentage of TWs in respective categories
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 11/39
Findings on developing testing
methodology
Merck kit could be used for mass scale As detection inTW water in Bangladesh (99% sensitivity);
As concentration between (10-24) for 10 µg/L and (50-99)
for 50 µg/L cut-off levels are mostly misclassified andneed to be reanalyzed in laboratory;
Field kit allows screening quickly in the presence of enthusiastic crowd, which helps to raise people’s
awareness about the As problem;
In order to reduce false identification severalprecautionary measures (eg. proper training, temp.humidity etc.) need to be ensured.
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 12/39
Approach II:
Identify sustainable mitigation option (s)
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 13/39
Problems encountered by users of
different alternative safe water options
Option Water source Major disadvantages
PSF Surface Many ponds used for fish-culture with use of poison to kill
predator fishes. High initial load of bacteria in pond waters.Acceptability not universal.
RWH Rainwater Rains not uniformly abundant in all areas; There is little or
no rain in dry season. Prohibitive cost for poor households.
Arsenicremoval
filters
Arsenic-contaminated
groundwater
Effectiveness in removing arsenic questionable,Unaffordable, Disposal of sludge is environmentally
problematic, Expensive and thus less sustainable on a long-
term basis particularly for poorer households.
Dugwell Sub-surface Susceptible to bacteriological contamination, May dry up
during winter, Presence of manganese, iron, and arsenic in
some wells.Deep
wells
Deep aquifer
(>250m)
More expensive than tubewells; Some uncertainties as a
long-term source for arsenic-safe water.
Piped
water
Deep aquifer
or treated
surface water
Expensive for country-wide adoption, Requires organization
to run.
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 14/39
71
95
85
100
67
0 10 20 30 40 50 60 70 80 90 100
Dugwells (231)
PSF (37)
RWH (90)
Arsenic removal filters
(10,569)
Bishudhya Filters (30)
Active Inactive
%
0
17
80
100
10
0 10 20 30 40 50 60 70 80 90 100
Re-installation of TWs (60)
PSF (23)
RWH (147)
Arsenic removal filters (10,569)
Bishudhya Filters (210)
Active Inactive%
Functional stautus of
different alternative
safe water options
(revised in 2004)
a) Sonargaon & Jhikargachha
upazilas (1999-2004)
b) Matlab upazila (2001-2004)
b)
a)
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 15/39
Findings on identifying sustainable
options
Less than 2% of the total provided options werefound to be in operation;
Instead, two new peoples’ driven initiative
emerged: Preferred use of arsenic safe tubewells;
Reinstallation of tubewells below 55-100mdepth instead of previous common depth of
20-30m. Identification of sustainable alternative safe
water options might be still needed for areaswhere none of the above methods would beapplicable.
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 16/39
Objective III:
Validate a people’s driven initiative for
sustainable source of drinking water
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 17/39
Litholog based on local driller
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 18/39
Prediction of risk for high
arsenic groundwater
REDOFF-
WHITE
WHITEBLACK
RISK
High Neglible?
REDOX
Very reduced Less reduced
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 19/39
Classification of samples: local
drillers vs. Munsel colour code
a) Black b) White
c) Red d) Off-white
Black White Off-White Red
Sediment colour
0.0
80.0
160.0
240.0
320.0
400.0
Asug/l
Astot
Black White Off-White Red
Sediment colour
0.0
4.0
8.0
12.0
16.0
20.0
Fetot
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 20/39
Geological cross section of the aquifers
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 21/39
There were minor discrepancies between thedriller’s colour classification of the sedimentsand the Munsell description;
The chemical characteristics of thegroundwater correlate well with the colour of the aquifer sediments;
Through the use of the technical knowledge of local drillers, it may be possible to obtain safewater in many parts of Bangladesh.
Findings on validating peoples’ driven
initiative
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 22/39
Summary conclusions
Identified the method of field testing kit for screening and monitoring of As-contaminatedTWs;
The safe water options need to be identified
considering the geo-physical and socio-culturalaspects of the people of the respective villages;
Detailed scientific investigation needs to becarried out to validate local drillers initiative (i.e.
re-installation of TWs at targetted depths).
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 23/39
Thanks for your attention
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 24/39
Safe water coverage and the climate change issues
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 25/39
Jakariya M, Vahter M, Rahman M, Wahed MA, Hore SK, Bhattacharya
P, Jacks G, Persson LA.. Screening of arsenic in tubewell water with
field test kits: Evaluation of the method from public health perspective.
Sci Total Environ, 2007, Vol. 379(2-3):167-75;
Jakariya M, von Bromssen M, Jacks G, Chowdhury AMR, Ahmed KM,
Bhattacharya P. Searching for a sustainable arsenic mitigation strategy
in Bangladesh: experience from two upazilas. Int. J. Environment and
Pollution, 2007, Vol. 31, Nos. 3/4: 415-430;
von Bromssen M, Jakariya M, Bhattacharya P, Ahmed KM, Hasan MA,
Sracek O, Jonsson L, Lundell L, Jacks G. Targeting low-arsenic
aquifers in Matlab Upazila, Southeastern Bangladesh. Sci Total
Environ, 2007, Vol. 379 (2-3):121-32.
Papers
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 26/39
Controls on
Arsenic
Occurrences:
Depth/Sub-surface
Geology
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 27/39
Deep Tubewell (DTW)
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 28/39
Rain Water Harvester (RWH)
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 29/39
Pond Sand Filter (PSF)
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 30/39
Rural piped water system
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 31/39
Improved Dugwell
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 32/39
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 33/39
—
———
— —
—
—
—
—
——
—
—
—
—
—
—
—
—
—
—
——
——
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
———
—
—
—
—
—
—
—
—
——
—
—
—
—
—
—
—
—
—
——
—
——
—
—
—
—
—
—
—
—
—
—
— —
V31
V60
V32
V61V62
D00
V10
V72
V11
W00
KM
.8.6.4.20
GIS unit, ICD DR,B
E
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 34/39
Source: Peter Ravenscroft
Arsenic Concentration at
different cut-off levels
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 35/39
Interpretation of kappa results :
Value of κ Strength of agreement
≤0.20 Poor
0.21 - 0.40 Fair
0.41-0.60 Moderate
0.61-0.80 Good
0.81-1.00 Very good
The kappa (κ) test is a test of agreement between two parameters-
e.g. between lab and field kit results in this particular case
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 36/39
Colour scale of Merck sensitive arsenic filed testing kit
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 37/39
Matlab Study Area
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 38/39
Alcan Filter
Arsenic Concentration change over time
8/14/2019 NSU Presentation 7Dec 2009 Alt
http://slidepdf.com/reader/full/nsu-presentation-7dec-2009-alt 39/39
Arsenic Concentration change over time
(Laboratory analysis)
n=246 (Feb 1999- Sep 2001)
3.7
46.749.6
0
10
20
30
40
50
60
%
N h C t ti i d C t ti d d