The physical and chemical properties of groundwater in Eloor, an industrial region, have been investigated to evaluate the extent of pollution. The study area was divided into four zones and a total of 40 water samples from different locations were collected, analyzed and correlation analysis has been carried out among the measured parameters. A comparison of the observed parameters with the limits prescribed by BIS revealed that in some area pH values are lower than the prescribed limit. The concentration of the major cations and anions were found to be significant. Magnesium and chloride exceed the desirable limit in some areas but less than the upper limit prescribed by BIS. Significant linear relationship was observed between pH, electrical conductivity, alkalinity, hardness, Ca2+, Mg2+and chloride. The importance of these parameters in predicting the quality characteristics of groundwater is discussed.

Contribution of terrestrial radiation due to the presence of naturally occurring radionuclides in soil and air constitutes a significant component of the background radiation exposure to the population. The concentrations of natural radionuclides in the soil and indoor air of Chellanam were investigated with an aim of evaluating the environmental radioactivity level and radiation hazard to the population. Chellanam is in the suburbs of Cochin, with the Arabian Sea in the west and the Cochin backwaters in the east. Chellanam is situated at ∼25 km from the sites of these factories. The data obtained serve as a reference in documenting changes to the environmental radioactivity due to technical activities. Soil samples were collected from 30 locations of the study area. The activity concentrations of (232)Th, (238)U and (40)K in the samples were analysed using gamma spectrometry. The gamma dose rates were calculated using conversion factors recommended by UNSCEAR [United Nations Scientific Committee on the Effects of Atomic Radiation. Sources and effects of ionizing radiation. UNSCEAR (2000)]. The ambient radiation exposure rates measured in the area ranged from 74 to 195 nGy h(-1) with a mean value of 131 nGy h(-1). The significant radionuclides being (232)Th, (238)U and (40)K, their activities were used to arrive at the absorbed gamma dose rate with a mean value of 131 nGy h(-1) and the radium equivalent activity with a mean value of 162 Bq kg(-1). The radon progeny levels varied from 0.21 to 1.4 mWL with a mean value of 0.6 mWL. The thoron progeny varied from 0.34 to 2.9 mWL with a mean value of 0.85 mWL. The ratio between thoron and radon progenies varied from 1.4 to 2.3 with a mean of 1.6. The details of the study, analysis and results are discussed.

The study of natural radiation exposure is of importance because it accounts for the largest contribution to the collective dose for the world population from all sources. Extent of exposure to natural radiation depends on the occupation, type of dwelling, location of habitation, and lifestyle of the population. All building materials contain various amounts of natural radionuclides as they are derived from the rocks and soils, which always contain natural radionuclides of Uranium ( 238 ), and Thorium ( ℎ) 232

The present study is aimed at measuring the concentration of primordial radionuclides in the soil samples of Eloor Island, an industrial area in Ernakulum District and evaluating the radiation exposure to the local population. The ambient radiation exposure rate was measured using portable scintillometer survey meter and the activity concentration of 232Th, 238U and 40K in the soil samples were analyzed using (5×4)” NaI(Tl) gamma spectrometer. The exposure rate measured using survey meter varied from 63 nGyh-1 to 374 nGyh-1. The activity concentration of 232Th, 238U and 40K in soil samples ranged from 44.8 Bq kg-1 to 792.8 Bqkg-1 for 232Th, 8 Bqkg-1 to 445.5 Bqkg-1 for 238U and 129 Bqkg-1 to 1160.5 Bqkg-1 for 40K. Hence the absorbed gamma dose and radiation hazard indices due to natural environmental radiation was done. The study showed no significant impact due to the NORM Industries in the Eloor Industrial region.

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