Presentation on theme: "Arsenic as a Global Pollutant Tiffany Berg March 26 th, 2011."— Presentation transcript:
Arsenic as a Global Pollutant Tiffany Berg March 26 th, 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 Very Low Low Moderate High Risk 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 waters 1 and mining 2 Fertilizing with poultry litter 3 Prior pesticide use in orchards, potato fields, and blueberry fields 4 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. http://mossnutritionblog.wordpress.com/2010/06/24/c hicken-litter-to-fertilize-or-not-to-fertilize/ http://www.flickr.com/photos/19779889@N00/4058241089/ http://www.coxcolvin.com/Arsenical_Pesticides.php
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 (BMDL 01 ) 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 Concentration of analyte RxRx CxCx X X X X X X
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 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. 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.
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 BangladeshAn Overview,, Agriculture, Ecosystems and Environment, 2006, 113, 1-16 2.5 million tube wells, 128 million people Field kits used to measure As in the regions groundwater are unreliable and that many wells in Bangladesh have been labeled incorrectly No-one has devised practical methods of ground water remediation, most studies and actions have focused on testing tube well water for arsenic.
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.
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.
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