Article
RADIOCHEMICAL EVALUATION OF GROUNDWATER AROUND MIKA URANIUM MINERALIZATION AND ENVIRONS.
Naturally occurring radon gas (222Rn) exists in groundwater and previous study of the problem of natural radioactivity in drinking water from wells drilled in rock types rich in uranium has shown tendency to have high radon concentration. It has been widely reported that radon is contributing the largest component of human exposures to natural radiation and it is considered as the second major cause of lung cancer, after cigarrete smoking. Seventeen (17) groundwater samples around Mika Uranium mineralization were collected and 222Rn concentrations were measured using the DURRIDGE RAD7 electronic radon detector. Radon (222Rn) concentrations in the groundwater ranged from 2350 to 46,200 Bq/m3 with an average of 29,400 Bq/m3 . The results show that 76.5% of the groundwater samples collected have 222Rn concentrations far above the US.E.P.A maximum contaminant level (MCL) of 11.1 Bq/l (for states without radon monitoring policy and enhanced indoor air programs), while 23.5% has values lower. Meanwhile, all 222Rn values were below the MCL of 100 Bq/l recommended by European Union (EU) for measurements that warrant consideration of possible remedial actions. Borehole samples show relatively higher 222Rn concentrations than samples collected from open-wells. The annual effective dose due to ingestion (Hing) of 222Rn in the groundwater ranged from 0.05 to 0.92 mSv, with an average of 0.59 mSv. These values are within the ICRP recommended reference level of 1 mSv/yr for the intake of radionuclide in water by the general public for a prolonged exposure.
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