HYDROCHEMISTRY, RADON IN GROUNDWATER AND ITS EXHALATION FROM ROCKS AROUND MIKA, N.E NIGERIA

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dc.contributor.authorDANIEL, Allen Sati
dc.date.accessioned2017-03-31T07:54:46Z
dc.date.available2017-03-31T07:54:46Z
dc.date.issued2016-04
dc.descriptionA THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF MASTERS DEGREE IN APPLIED GEOLOGY (HYDROGEOLOGY) DEPARTMENT OF GEOLOGY FACULTY OF SCIENCE AHMADU BELLO UNIVERSITY, ZARIA NIGERIAen_US
dc.description.abstractIn Nigeria, groundwater is the most widely utilized source of freshwater for consumption and other domestic uses, as well as for irrigational purposes but its quality still remains a major issue. This study was undertaken to evaluate radon in groundwater, its emanation/exhalation from rocks, associated radiological hazards and present the hydrochemical status of the groundwater, around Mika uranium mineralization, Northeastern, Nigeria. 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 concentrations. Radon (222Rn) was widely reported as contributing the largest component of human exposures to natural radiation and it is the second major cause of lung cancer, after cigarette smoking. Seventeen (17) groundwater samples and fifteen (15) rock samples were collected. Radon in groundwater and exhalation from rock measurements were carried-out using the DURRIDGE RAD7 electronic radon detector. Radium, thorium and potassium concentrations were determined using the 76x76mm NaI (Tl) detector, optically coupled to a photomultiplier (PMT) and chemical properties of the groundwater was determined using Atomic Absorption Spectrometry (AAS), Flame photometry and Titrimetric methods. Radon concentrations in groundwater vary from 2350 to 46,200 Bqm-3 with an average of 29,400 Bqm-3 against the U.S.EPA maximum contaminant level (MCL) of 11.1 Bq/l (11,100 Bqm-3) for States without monitoring policy and enhanced indoor air policy. Radon exhalation from rock ranged from 39.7 to 262 Bqm-3 with an average of 137 Bqm-3. The emanation coefficient ranged between 0.7 to 5.1 with an average of 2.17 and an exhalation rate range of between 0.73 to 4.83 mBqkg-1h-1, an average of 2.52 mBqkg-1h-1. The potential dose due to degassing of radon from groundwater, show an annual absorbed dose range of 37.06 to 728.48 mSvy-1 with an average of 463.59 mSvy-1, an annual effective dose range of 88.94 to 1748.35 mSvy-1 with an average of 1112.62 mSvy-1 and annual dose due to ingestion of 222Rn ranged from 0.05 to 0.92 mSvy-1 with an average of 0.59 mSvy-1 which is within ICRP recommended reference level of 1 mSvy-1 but far above WHO recommended level of 0.1 mSvy-1. Radium, thorium and potassium activity concentrations ranged from 15.33 to 63.38 Bqkg-1(an average of 35.72 Bqkg-1), 41.51 to 333.64 Bqkg-1 (an average of 161.86 Bqkg-1) and 161.73 to 2166.56 Bqkg-1 (an average of 1153.25 Bqkg-1), respectively. The reported world average for 226Ra, 232Th and 40K is 35, 30 and 400 Bqkg-1, respectively. Dose rates due to gamma radiation from combined contributions from 226Ra, 232Th and 40K, ranged from 79.50 to 270 nGyh-1, with an average of 164.02 nGyh-1 (higher than the world median value of 60 nGyh-1). Annual effective dose ranged from 0.24 to 0.83 mSvy-1 with an average of 0.50 mSvy-1. Radium equivalent of the rock samples ranged from 163.97 to 603.46 Bqkg-1 with an average value of 355.99 Bqkg-1, this value is lower than the world accepted upper limit of 370 Bqkg-1. External hazard index ranged from 0.44 to 1.63 with an average value of 0.96, close to the world accepted upper limit of 1 (unity). The water types identified are; HCO3-Na (82%), Na-SO4 (12%) and Ca-Cl (6%). Based on Wilcox’s classification, with respect to percent sodium (%Na), 11.8% of the groundwater samples were considered good for irrigation, 52.9% were permissible, 29.4% were doubtful while 5.9% were unsuitable for irrigation purposes.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/8817
dc.language.isoenen_US
dc.subjectHYDROCHEMISTRY,en_US
dc.subjectRADON,en_US
dc.subjectGROUNDWATER,en_US
dc.subjectEXHALATION,en_US
dc.subjectROCKS,en_US
dc.subjectMIKA,en_US
dc.subjectN.E NIGERIA,en_US
dc.titleHYDROCHEMISTRY, RADON IN GROUNDWATER AND ITS EXHALATION FROM ROCKS AROUND MIKA, N.E NIGERIAen_US
dc.typeThesisen_US
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