Classification of Surface and Deep Soil Samples Using Linear Discriminant Analysis

W. Wasim, M. Ali, M. Daud


A statistical analysis was made of the activity concentrations measured in surface and deep soil samples for natural and anthropogenic -emitting radionuclides. Soil samples were obtained from 48 different locations in Gilgit, Pakistan covering about 50 km2 areas at an average altitude of 1550 m above sea level. From each location two samples were collected: one from the top soil (2-6 cm) and another from a depth of 6-10 cm. Four radionuclides including226Ra, 232Th 40K and 137Cs were quantified. The data was analyzed using t-test to find out activity concentration difference between the surface and depth samples. At the surface, the median activity concentrations were 23.7, 29.1, 4.6 and 115 Bq kg-1 for 226Ra, 232Th, 137Cs and 40K respectively. For the same radionuclides, the activity concentrations were respectively 25.5, 26.2, 2.9 and 191 Bq kg-1 for the depth samples. Principal component analysis (PCA) was applied to explore patterns within the data. A positive significant correlation was observed between the radionuclides 226Ra and 232Th. The data from PCA was further utilized in linear discriminant analysis (LDA) for the classification of surface and depth samples. LDA classified surface and depth samples with good predictability.

Full Text:



R. L. Kathren, "NORM sources and their origins". Appl. Radiat.

Isot., vol. 49, p. 149-168, 1998.

UNSCEAR, Effects of Atomic Radiation, United Nations, New

York, 1982.

NCRP, Ionizing radiation exposure of the population of the United

States, National Council on Radiation Protection and

Measurements, Bethesda, 1988.

H. J. M. Bowen, Environmental chemistry of the elements,

Academic Press, London, 1979.

NCRP, Report No. 50, Environmental Radiation Measurements,

National Council on Radiation Protection and Measurement,

Washington DC, 1992.

G. R. Lloyd, S. Ahmad, M. Wasim and R. G. Brereton, "Pattern

recognition of inductively coupled plasma atomic emission

spectroscopy of human scalp hair for discriminating between

healthy and hepatitis C patients", Anal. Chim. Acta, vol. 649,

p. 33-42, 2009.

Z. Zhang, H. Zhuo, S. Liu and P. de B Harrington, "Classification

of cancer patients based on elemental contents of serums using

bidirectional associative memory networks", Anal. Chim. Acta,

vol. 436, p. 281-291, 2001.

C. Peltz and M. Bichler, "Classification of archaeologically

stratified pumice by INAA", J. Radioanal. Nucl. Chem., vol. 248,

p. 81-87, 2001.

I. Jolliffe, "Principal component analysis", Wiley Online Library,

Massart, B. Vandeginste, L. Buydens, S. De Jong, P. Lewi and

J. Smeyers-Verbeke, Handbook of Chemometrics and

Qualimetrics, Part A, Elsevier, Amsterdam, 1997.

B. G. M. Vandeginste, D. L. Massart, L. M. C. Buydens, S. D.

Jong, P. J. Lewi and J. Smeyers-Verbeke, "Handbook of

chemometrics and qualimetrics, Part B", Elsevier, Amsterdam,

A. Zhu, "Mapping soil landscape as spatial continua: the neural

network approach". Water Resources Research, vol. 36, p. 663-

, 2000.

P. H. Fidêncio, I. Ruisánchez and R. J. Poppi, "Application of

artificial neural networks to the classification of soils from Sao

Paulo state using near-infrared spectroscopy", Analyst, vol. 126,

p. 2194-2200, 2001.

S. Dragović and A. Onjia, "Classification of soil samples

according to their geographic origin using gamma-ray

spectrometry and principal component analysis". J. Environ.

Radioact., vol. 89, p. 150-158, 2006.

S. Dragovic and A. Onjia, "Classification of soil samples

according to geographic origin using gamma-ray spectrometry and

pattern recognition methods". Appl. Radiat. Isot., vol. 65, p. 218-

, 2007.

J. F. Ivanac, D. M. Traves and D. King, "Records of the Geological

Survey of Pakistan, vol. VIII Part 2", Geological Survey of

Pakistan, 1956.

M. Ali, M. Wasim, M. Arif, J. H. Zaidi, Y. Anwar and F. Saif,

"Determination of the natural and anthropogenic radioactivity in

the soil of Gilgit—a town in the foothills of Hindukush range",

Health Phys., vol. 98 (Supplement 2), p. S69-S75, 2010.

S. Wold, K. Esbensen and P. Geladi, "Principal component

analysis". Chemom. Intell. Lab. Syst., vol. 2, p. 37-52, 1987.

M. Daud, M. Wasim, N. Khalid, J. H. Zaidi and J. Iqbal,

"Assessment of elemental pollution in soil of Islamabad city using

instrumental neutron activation analysis and atomic absorption

spectrometry techniques", Radiochim. Acta, vol. 97, p. 117-122,

M. Wasim, M. S. Hassan and R. G. Brereton, "Evaluation of

chemometric methods for determining the number and position of

components in high-performance liquid chromatography detected

by diode array detector and on-flow 1H nuclear magnetic resonance

spectroscopy", Analyst, vol. 128, p. 1082-1090, 2003.

R. G. Brereton, Chemometrics: Data Analysis for the Laboratory

and Chemical Plant, Wiley, Chichester, 2003.


  • There are currently no refbacks.