RESEARCH PAPER Determination of radioactivity levels and associated hazards of coastal sediment from south east coast of Tamil Nadu with statistical approach S. Sivakumar 1 • A. Chandrasekaran 2 • G. Senthilkumar 3 • M. Suresh Gandhi 4 • R. Ravisankar 5 Received: 27 April 2016 / Accepted: 23 February 2017 Ó Shiraz University 2017 Abstract The concentration of 238 U, 232 Th and 40 K in sediment samples collected from Thazhankudato Kodiyakkarai along the east coast of Tamil Nadu, India was measured using c-spectrometry. Measured mean activity concentrations are 3.3, 40.45 and 389.28 Bq kg -1 for 238 U, 232 Th and 40 K, respectively. The average activity concentration of 232 Th is slightly higher than the world average value. The radiation hazards such as radium equivalent activity, absorbed gamma dose rates in air, the annual gonadal dose equivalent, annual effective dose equivalent, external hazard index, internal hazard index, representative level index and excess lifetime cancer risk associated with the radionuclides were calculated. Heat production rate of sediments and spatial distribution of radionuclides is studied. The multivariate statistical anal- ysis, such as Pearson correlation, principal component and cluster analysis were applied to know the existing relation between radiological variables. From the analysis, the radioactivity levels in sediment samples do not pose any environmental health problem. Thus, the presented data provide a general background of the detectable radionu- clides for the study area and can be helpful in future epi- demiological studies. Keywords Sediments Á Gamma ray spectrometry Á Radiation hazards Á Multivariate statistical analysis 1 Introduction Man is continuously exposed to ionizing radiation from naturally occurring radioactive materials (NORM). The origin of these materials is the Earth’s crust. The exposure of ionizing radiations from natural sources such as soil, sediments and rocks, cosmic rays entering the earth’s atmosphere. The radiological implication of these radionuclides is due to the gamma ray exposure of the body and irradiation of lung tissue from inhalation of radon and its daughters. The assessment of gamma radiation dose from natural sources is of particular importance as natural radiation is the largest contributor to the external dose of the world population (UNSCEAR 1988). Many areas in the world such as Australia, Brazil, China, India, Iran, and Japan possess high levels of natural radiation. In the recent years, studies on the high back- ground radiation areas in the world have been of prime importance for risk estimation due to long term low-level whole body exposures to the public. The high radiation levels are due to the presence of large quantities of natu- rally occurring radioactive minerals in the rocks, soils, sediments, etc. Among the various geological formations, sediment plays a predominant role in aquatic radioecology and plays a role in accumulating and transporting con- taminants within the geographic area (Suresh Gandhi et al. & R. Ravisankar ravisankarphysics@gmail.com; chandrasekarana@ssn.edu.in 1 Department of Physics, KL University, Green Fields, Vaddeswaram, Guntur Dist. 522 502, Andara Pradesh, India 2 Department of Physics, SSN College of Engineering, Kalavakkam, Chennai 603110, Tamilnadu, India 3 Department of Physics, University College of Engineering (A Constituent College of Anna University, Chennai), Arni, Thiruvannamalai Dist. 632326, Tamilnadu, India 4 Department of Geology, University of Madras, Guindy Campus, Chennai 600 025, Tamilnadu, India 5 Post Graduate and Research Department of Physics, Government Arts College, Thiruvanamalai 606603, Tamilnadu, India 123 Iran J Sci Technol Trans Sci DOI 10.1007/s40995-017-0184-2