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

2

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)

13

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