Spatio-temporal Identification of Regions with Anomalous Values of 222 Rn in Groundwater of Madurai District, Tamilnadu, India

Measurement of dissolved radon (222 Rn) activity concentration in groundwater samples from private and public hand pumps, and in bore wells located at Madurai district of Tamilnadu, India, are presented. The study attempts to identify the background value of 222 Rn in groundwater of hard rock terrain and the main aquifer contributing 222 Rn, and to determine if any correlation exists with observed field parameters. Measured parameters included pH, TDS, Temperature and 222 Rn in 42 samples for two seasons (South West Monsoon [SWM] and North East Monsoon [NEM]). The results show that the 222 Rn activity concentration of the samples ranged from 0.049 to 59.952 Bq/L in South west monsoon and 0.12 to 211.60 Bq/L in North east monsoon. The higher activity was noted in NEM and the highest 222 Rn concentrations were observed in granitic terrains in both seasons. The average values of the parameters studied shows that there is a general decrease of TDS and Temperature, but an increase in 222 Rn and pH during NEM. The spatial representation of the activity shows that maximum values are in the north eastern part of the study area. Further, correlations between the measured parameters show that temperature has a negative correlation to the samples of charnockite formation during both seasons; pH and TDS also show negative relationships to 222 Rn during SWM

Determination and quantification of major climatic parameters influencing the CO2 of Lascaux Cave

High and low CO2 partial pressure (Pco2) levels can induce consequences to the internal system of a karstic cave. This then can further affect the state of the cave. Subsequently, speleothem growths and the walls with prehistorical paintings and engravings will be affected with either calcite dissolution or precipitation. Thus, pinpointing the major components of Pco2 is found indispensable. In this paper, a method is proposed in order to (1) identify the major components of the Pco2 and (2) quantify each specific contribution to the Pco2. Pco2, air temperature, air pressure, and water flow were measured from 2008 to 2010 in Lascaux Cave (Southwest of France). Pco2 varied from 0.62% (6200 ppm) in summer to 0.04% (400 ppm) in winter. We identified three major components: (1) seasonal: component A; (2) low frequency: component B; and (3) high frequency: component C. The method is applied to estimate the contribution of each component. Component A was modelled with a sinusoid curve fitted to the Pco2 measures. This component was subtracted from the measured Pco2. Then, from the remaining value of Pco2, Fourier transform, frequency filtering, and inverse Fourier transform were applied to separate high- and low-frequency components. As a result, the seasonal component A contributes 77% of the measured Pco2, while components B and C supply 13 and 11%, respectively. The three identified components have links with environmental parameters such as temperature, water flow, and atmospheric pressure. Hypotheses were proposed to describe these links. Knowledge on these aspects can help in cave management and protection specifically in answering the question: which parameter should be given more attention

Radon in air and water

Radon is a natural radioactive gas that you cannot see, smell, or taste and that can only be detected with special equipment. It is produced by the radioactive decay of radium, which in turn is derived from the radioactive decay of uranium. Uranium is found in small quantities in all soils and rocks, although the amount varies from place to place. Radon decays to form radioactive particles that can enter the body by inhalation. Inhalation of the short-lived decay products of radon has been linked to an increase in the risk of developing cancers of the respiratory tract, especially of the lungs. Breathing radon in the indoor air of homes contributes to about 15,000 lung cancer deaths each year in the United States and 1,100 in the UK (HPA 2009). Only smoking causes more lung cancer deaths