Arsenic as a Global Pollutant
Tiffany Berg
March 26th, 2011
Health effects of arsenic poisoning
• Keratosis
• Internal tumors
• Cancers of the skin, liver, bladder, and lungs.
P. Vineis and W. Xun; Ann. Oncol.; 2008, 20, 205-212.
“Special Report: Policy. A review of human carcinogens – Part C: metals, arsenic, dust and fibres.” 2009, 10., 453-454. Acessed
22March2011: http://www.thelancet.com/oncology
Arsenic contamination in drinking water
Risk
Very Low
Low
Moderate
High
Figure 1. Estimated risks for arsenic contamination in drinking water.
R. P. Schwarzenbach, T. Elgi, T. B. Hofstetter, U. von Gunten, and B. Wehrli; Annu. Rev. Environ. Resour. 2010, 35, 109-136.
Where does As come from?
• In Bangladesh, Cambodia and Vietnam geological composition
of aquifers
• In U.S. and Eastern Europe, weathering of arsenic-rich source
rocks in mountain ranges, deposition in river floodplains, and
flat and humid terrain where arsenic is released into the
water
• In U.S. midwest, eastern Australia and central Asia high pH
mobilize As in oxygen-rich groundwater
R. P. Schwarzenbach, T. Elgi, T. B. Hofstetter, U. von Gunten, and B. Wehrli; Annu. Rev. Environ. Resour. 2010, 35, 109-136.
United States
Figure 2. Probability map of arsenic concentration in the United States. Black
dots represent measured As concentrations above 10 µg L-1.
M. Amini, K.. C Abbaspour, M. Berg, L. Winkel, S. J. Hug, E. Hoehn, H. Yang and A. Johnson; Environ. Sci. Technol. 2008, 42, 3669-3675.
Bangladesh
Figure 3. Probability map of arsenic concentration in Bangladesh.
Black dots represent measured As concentrations above 10 µg L-1.
M. Amini, K.. C Abbaspour, M. Berg, L. Winkel, S. J. Hug, E. Hoehn, H. Yang and A. Johnson; Environ. Sci. Technol. 2008, 42, 3669-3675.
Arsenic pollution
Industrial waste waters1 and mining2
http://www.flickr.com/photos/19779889@N00/4058241089/
Fertilizing with poultry litter3
http://mossnutritionblog.wordpress.com/2010/06/24/c
hicken-litter-to-fertilize-or-not-to-fertilize/
Prior pesticide use in orchards, potato fields, and blueberry fields4
http://www.coxcolvin.com/Arsenical_Pesticides.php
1. Z. Wang, B. He, X. Pan, K. Zhang, C. Wang, J. Sun, Z. Yun and G. Jiang; Sci. China Ser. B., 2010, 53, 1809-1817.
2. O. Gunduz, C. Simsek and A. Hasozbek; Water Air Soil Pollut., 2010, 205, 43-62.
3. C. W. Liu, C. C. Lin, C. S. Jang, G. R. Sheu and L. Tsui; J. Plant Nutr. Soil Sc.; 2009, 172, 550-556.
4. S. Quazi, D. Sarkar, and R. Datta.; Appl. Geochem.; 2010, 25, 1422-1430.
Irrigation with contaminated water
http://scripts.mit.edu/~brehm/beccablog/
Threshold limits for arsenic
Bangladesh
50 ppb in drinking water
Environmental Protection Agency (EPA) and the World Health Organization (WHO)
10 ppb in drinking water
Food and Drug Administration of the United States (FDA)
Tolerance level for arsenic byproducts of animals treated with veterinary drugs
0.5 ppm in eggs and uncooked tissues of chicken and turkey
2 ppm uncooked edible byproducts of swine
Food and Agriculture Organization of the United Nations (FAO)/WHO in 2010
Provisional tolerable weekly intake (PTWI) 3.0 µg/kg body weight per day
European Food Safety Authority (EFSA) in 2009
Benchmark dose lower confidence limit (BMDL01) 0.3 µg/kg body weight per day
Measurement Issues
Julian Tyson
Department of Chemistry
UMass Amherst
Need to be able to measure arsenic at single-digit
part per billion concentrations in a wide variety of
sample materials including:
Water, soil, food, beverages.
Measurement needs to be accurate and precise.
Many laboratory-based methods based on
instrumental techniques are capable of doing this.
Instrumental analysis. Most based on solutions.
Calibrate instrument at time of use. Prepare series
of solutions of known concentration (standards),
measure response and plot response as a function of
concentration.
Instrument
response
X
X
X
Rx
X
X
X
Cx
Concentration
of analyte
Most commonly used techniques are based on the
measurement of atoms or ions of arsenic including
Atomic absorption spectrometry
Atomic emission spectrometry
Atomic fluorescence spectometry
Atomic mass spectrometry
Flames, furnaces, or inductively coupled plasmas
create atoms from spray of sample solution.
Also electrochemical and colorimetric procedures
have been used.
Caldwell, et al. “Searching for an optimum solution to the
Bangladesh arsenic crisis,” Social Science & Medicine, 2003, 56,
2089–2096.
“The reason for caution about precipitating a great suspicion of
tubewells or a rapid turning against them is that no alternative
source of water may prove very satisfactory.”
“the most urgent need is not changing the source of water but
comprehensive national water testing providing essential
information to households about which wells are safe and which
are not . . . all progress depends on nationwide testing and
retesting of all tubewells, a process that has hardly started.”
Arsenic contamination in groundwater: some
analytical considerations.
David G. Kinniburgh & Walter Kosmus
Talanta, 58 (2002) 165–180
“For countries such as Bangladesh with a significant
groundwater arsenic problem, there is an urgent need
for the arsenic-contaminated wells to be identified as
soon as possible and for appropriate action to be taken.
This will involve the testing of a large number of wells,
potentially up to 11 million in Bangladesh alone.
Field-test kits offer the only practical way forward in
the timescale required.”
Many countries and rural communities do not have
access to this kind of chemical measurement
technology.
Rely on test kits. Colored spot on strip is matched
to a series of preprinted colors.
Has been criticism of these kinds of tests
Hossain “Arsenic Contamination in
Bangladesh—An Overview,”, Agriculture,
Ecosystems and Environment, 2006, 113, 1-16
2.5 million tube wells, 128 million people
“No-one has devised practical methods of ground water
remediation, most studies and actions have focused on testing
tube well water for arsenic.”
“Field kits used to measure As in the region’s groundwater
are unreliable and that many wells in Bangladesh have been
labeled incorrectly”
Need to be able to measure arsenic at single-digit
part per billion concentrations in a wide variety of
sample materials including:
Water, soil, food, beverages.
Measurement needs to be accurate and precise.
We think that digital image analysis may
significantly improve the reliability of the tests.
Comparing Tests strip with Hach Kit
Standards
Camera Usage
I used the camera and digital
imaging to find R, G, B
components with software
you will be using shortly.
I examined paint chip
R,G, B values with
the Hach kit standard
colors using photos
and the digital
imaging software
developed by John.
Compare test strips with standards
Fluorescent Light Standards
120
R
G
B
V
a
l
u
e
s
100
80
60
40
20
0
0
100
200
300
As (III) concentration ppb
400
500
600
Incandescent Light Standards
120
100
R
G
B 80
V
a
l
u
e
s
60
40
20
0
0
100
200 As (III) concentration
300
ppb 400
500
600
Natural Light Standards
120
100
R
G
B
V
a
l
u
e
s
80
60
40
20
0
0
100
200
300
As (III) concentration ppb
400
500
600
New standard color chips
50 ppb
100 ppb
250 ppb
500 ppb
25 ppb
10 ppb
0 ppb