1
Jornadas de Investigacion del Departamento de Sistemas
Estadistica, desde Astronomia a Contaminacion de
Agua Subterranea
Elia B. Marquez, Patrick L. Gurian, Philip Goodell, Alberto Barud Z
Abril 26, 2012
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Porque usar Estadistica ?
Caso de Estudio:
Investigar el origen y procesos de movilizacion del
arsenico en el agua subterranea en El Paso TX.
Porque Estadistica ?
… por inaccesibilidad al objeto de estudio.
No podemos ir al espacio y medir directamente las
estrellas, quasar, ..
No podemos cavar todos los pozos donde queramos,
No podemos ir al Popo y medir su energia !
Resultados indirectos
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En Astronomia ...
Corrimiento al Rojo velocidad,
distancias, energias,
Luminiscencia Nuevo conocimiento !
Figure 6.79 Redshift magnitude relation for a
complete set of radio quasars..(Davie, The New Physics)
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Etapas de la Investigacion
Estado del Arte: papers, libros
Recabar Informacion
Geochemistry, Fisica, Math, etc..
Analisis Estadistico
Disenyo y Realizacion de Experimentos
Conclusiones
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Caso de Estudio
Contaminacion por Arsenico en Aguas Subterraneas
en El Paso, TX, USA
Archivos, Laboratorios y Muestras de:
EPWU y UTEP
http://nationalatlas.gov/natlas/Natlasstart.asp
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Arsenic in the Groundwater of El Paso County
EPWU
Asarco
Refinery
Sierra
Juarez
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Mecanismos de Movilizacion
Desorption
Reduction
Evaporation
Up-flowing (Geothermal and Non-Geothermal)
Human pollution (Industrial, Smelter, Extraccion, ... )
Procesos No excluyentes
Competitive Desorption
compete for ≡ FeOH sorption sites
(CO3-2, PO4
-3, SO4-2, Cl
-, F
-, OH
-,NO3
-1 )
Higher pH ���� proclivity for desorption
≡FeOH + AsO43- + 3H+ ↔ ≡FeH2AsO4 + H2O
≡FeOH + CO32- + 2H+ ↔ ≡FeHCO3 + H2O
Expected
POSITIVE correlations (pH,CO3-2,PO4
-3,SO4-2,F
-) with As
≡FeOH
≡FeOH
Reductive Dissolution
Fe(III) + e- � Fe(II)
less soluble more soluble
As(V) + 2e- � As(III)
more strongly adsorbed less
Expected
NEGATIVE correlations (O2, CO3-2,PO4
-3,SO4-2, NO3
–, ) with As
• POSITIVE correlation As with Fe/Mn/Organic Carbon
• Present As (III), rather than As (V)
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Analisis Estadistico
Bivariate analysis
Multivariate analysis
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Spearman’s Correlations Coefficients between As and variables shown (Aggregated by well)
Basin pH Fe Mn SiO2 Ca Ca% Na Na% K
Hueco .4** 0.03 -0.10 -0.10 -0.04 -.45** .5** .6** -0.05Mesilla .4** -.3 - .6** -0.10 - .5** -.4** - .4* .5** -.4*
Mg Mg% Cl Cl%
Hueco -0.3** -.6** .4** .3** - .4** -.4** .3** 0.03 .2*
Mesilla - .55** -.5** -.4* 0.20 -.45** -0.05 - .5** -.2 0.3
Depth TDS EC F n#
Hueco - .3** - .4** 0.1 .35** .3** -.2* 229Mesilla .5** -0.1 -0.20 - .5** - .4** 0.1 58
HCO3
HCO3 % SO
4SO
4 % CO
3
NO3
PO4
n#: number of wells
may indicate that DESORPTION occurs
BOTH sets occur
may indicate that Cation-Exchange, Evaporation or Brine Dissolution occur
•Correlation significant at 5% level ** Correlation significant at 1% level
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Observed Cummulative Prob
1.00.75.50.250.00
Exp
ecte
d C
um
Pro
b
1.00
.75
.50
.25
0.00
Observed Cum Prob
1.00.75.50.250.00
Exp
ecte
d C
um
ula
tive
Pro
ba
bili
ty
1.00
.75
.50
.25
0.00
Ejemplos de Regresiones de As en Hueco, Normal PP-plot for
the Standardized Residuals, Coefficients, Significance
Coefficientsa
.000
-.177 .027
(Constant)
F ppm
Beta
Standardized
Coefficients
Sig.
Dependent Variable: As archivesa.
Coefficientsa
.960
-1.303 .935
2.858 .894
-.419 .788
.263 .886
-.275 .714
-1.650 .848
(Constant)
NA_PPM_1
CL_PPM_1
EC_AV_1
PH_AV_1
PHLEAC_1
HARD_P_1
Beta
Standardized
Coefficients
Sig.
Dependent Variable: AS_ARC_1a.
Adjusted R-square
.03
Adjusted R-square .2
Normal Lines
As water = ββββo + ββββ1X1 + ββββ2 X2 + ββββ3X3 + ββββ4 X4
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Observed Cumulative Prob
1.00.75.50.250.00
Exp
ecte
d C
um
ula
tive
Pro
b
1.00
.75
.50
.25
0.00
Multivariate Regression
sugiere: Cat-Exch/Desorption
en Hueco, descartando Evaporation
Coefficientsa
.007
.822 .000
.944 .010
-1.552 .000
.249 .001
.225 .002
.434 .002
(Constant)
Na
Cl
TDS
pH
CO3
SO4
Beta
Standardized
Coefficients
Sig.
Dependent Variable: AS_ARC_1a.
R-square .47 Adjusted .45Best
value
competitive
desorption from
anions
No support for simple
evaporation/concentration
Brine dissolution
association
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Experimentos
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Test
* Desorption
* Local Origin.
1
15 Cuttings Sampled and Leached
Clear sands
Well 9
Dark Sands
���� high Fe
Cuttings Experimentos
Leaching cuttings
pH 9, and pH 10
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Spearman’s Correlation Coefficients. Both basins together
.62*.09.22.65*.54As leach pH10
.18.52.66**.61*As leach pH 9
.56.18 .48TOC solid
.43.71**Fe solid
.41As solid
As solid Fe solid TOC solid As leach 9
As
aqueous
* Correlation significant at 5% level
** at 1% level
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Resultados
Analisis Estadistico
Cuttings (solidos) Experimentos
High As in water ~ High As in cuttings
Desorption, Cation-Exchange/Brine Dissolution
High As in water ~ High As leached
Local Origin
Desorption
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Conclusiones
Arsenic desorption es un mecanismo
significativamente compatible con
6,000 datos archivados +
30 datos resultado de 2 experimentos,en “el Hueco” El Paso Texas, USA
La mas probable fuente de arsenico esta en las
rocas de las montanas
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Mecanismos de Movilizacion / Origen
Desorption
Reduction
Evaporation
Up-flowing (Geothermal and Non-Geothermal)
Human pollution (Industrial, Agriculture, Cu Extraccion, ...
Desorption
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Referencias importantes
Butler Kate,“Arsenic Contamination in Bangladesh: A look into how arsenic enters the groundwater”, Environmental Forensics presentation, 2004
Goodell PC, “Geologic Field Trip of the El Paso-Juarez Area”
Gurian P, Small M, Lockwood J and Schervish “Addressing uncertainty and conflicting cost estimates in revising the arsenic MCL”, Environ. Sci. Technol. 2001, 35, p4414.
Montoya T, Gurian P L 2004 “Modeling Arsenic Removal by Coagulation with Ferric Salts: Effects of pH
and Dosage”, Proceedings of the Texas Water 2004 Conference.
Percival R, Schroeder, Miller, Leape “Environmental Regulation. Law, Science and Policy” 4th,
Aspen, 2003
Reimann C, Banks D “Setting action levels for drinking water: Are we protecting our health or our
economy (or our backs!)?” Elsevier 2004, doi: 10.1016/j.scitotenv.2004.04.007
Rasul SB, Munir A, Hossain, Khan, Alauddin, Hussam, “Electrochemical measurement and speciastion of inorganic arsenic in groundwater of Bangladesh”, Talanta 58, 2002.
Scott K. Anderholm and Charles E. Heywood“Chemistry and Age of Ground Water in the Southwestern
Hueco Bolson, New Mexico and Texas” USGS Report 02-4237 , 2003
Siegel F R, “Environmental Geochemistry of Potentially toxic Metals”. Springer 2002.
Smith A “As Epidemiology and drinking water standards” Science 296, June 2002.
U.S. EPA, Federal Register part VIII, 40 CFR 2001, Vol. 66, No. 14
USGS, ”Arsenic in ground water of the Willamette basin, Oregon” http:// Oregon.usgs.gov/pubs_dir/Online/Html/WRIR98-4205, 1998
Webster and Nordstrom D K, 2003 “Geothermal Arsenic, Chapter 4” in Welch A H and Stollenwerk
K G, 2003 “Arsenic in Ground Water”, Kluger Academic Publishers
www.EPWU.org ,www.wikipedia.org,www.holycross.edu/departments/chemistryhttp://www.usda.gov/rus/water, www.watts.premier.com/sdwa/pou-funding.htm
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Gracias