Indoor radon and thoron concentrations have been measured in the year 2015-2016 using the newly developed pin-hole based radon/thoron discriminating dosimeters with single entry. The measurements have been carried out in fifty dwellings of eight different villages/town situated in Saiha and Lawngtlai District, Mizoram. Dwellings were selected from the building type along with an idea of different ventilation conditions which affects the indoor concentration. Reinforce Cement Concrete (RCC) type of buildings are found to have the highest concentration of indoor radon (100.34 ± 7 Bq/m3) and thoron (41.41 ± 18 Bq/m3) and grounded house are found to have higher concentration compared to that of house with crawl space. However, the concentrations obtained in this work lies in the range covered by nationwide survey result as well as the ICRP regulations.

Temperature is one of the most important ecological factors which play a significant role on the earth, and all the living organisms have evolved various methods to meet extremes of temperature. Seasonal temperature variations are quite significant in freshwater lakes and ponds. The present study deals with the effect of seasonal variations of water temperature on different water quality parameters of Tamdil lake, Mizoram, India, for a period of two years, i.e., from March, 2014 to February, 2016. The water samples were collected from five sampling sites, and the average reading was calculated for each of the water quality attributes namely, temperature, pH, Dissolved Oxygen (DO) and Biological Oxygen Demand (BOD). The water samples were analyzed monthly, and the results are computed on seasonal basis, i.e., pre-monsoon, monsoon, post- monsoon and winter seasons. Statistically, there was a positive and significant relationship between water temperature and pH, and negative significant relationship between temperature and DO. A negative correlation was observed between temperature and BOD. The result shows that there is a significant seasonal variation in physico-chemical parameters. The lake has not reached the polluted stage yet.