Hydrogeologic evaluation of radon activities in groundwater from the Rocky Mount granite pluton, Rocky Mount, North Carolina / by Richard J. Tarravechia.

Author/creator Tarravechia, Richard J. author.
Other author Spruill, Richard K., degree supervisor.
Other author East Carolina University. Department of Geology.
Format Theses and dissertations
Production1989.
Description[iv], 43 leaves : illustrations ; 28 cm
Supplemental ContentAccess via ScholarShip
Subjects

Summary The effect of recharge from the overlying sediments on radon-222 activities in groundwater from the Rocky Mount granite pluton was studied. In two continuous constant rate pump tests of 27 hours (Q=5gpm) and 53 hours (Q=8gpm), maximum radon activities were reached after 3 and 5 hours respectively; then activities declined at an average rate of 6 pCi/l/hr as induced recharge from the overlying sediments reached the well bore and diluted the well water. In a 30 hour discontinuous pump test, maximum activities were reached during the first non-pumping cycle, thereafter activities dropped at an average rate of 24 pCi/l/hr. Two in situ remediation techniques for lowering radon-222 activities in well water were tested. De-emanation Involves pumping compressed air down the well bore and through a bubble generating phase separator located at the bottom of the well. After fifty minutes radon 222 activities were reduced by 93% (2299 to 148 pCi/1). When initial activities are under 2500 pCi/1, this technique is capable of producing over 200 gallons of water under 500 pCi/1 in approximately two hours. During de-emanation, radon-222 activities in air from the well rise to as much as 1660 pCi/1. Shower-head aeration involves forcing pumped well water through a shower head, and back down the well. After sixty minutes radon-222 activities had decreased by 75%, from 2100 to 521 pC/1. Under static conditions, unsupported radon in water from a granite well decays and a vertical gradient develops, with radon activities increasing with depth. Factors which control this may be diffusion of radon into the atmosphere from near surface water, and the Increased solubility of radon at increased pressures and decreased temperatures at depth.
General noteSubmitted to the faculty of the Department of Geology.
General noteAdvisor: Richard K. Spruill
Dissertation noteM.S. East Carolina University 1989
Bibliography noteIncludes bibliographical references (leaves 32-33).
Genre/formdissertations.
Genre/formAcademic theses.
Genre/formAcademic theses.
Genre/formThèses et écrits académiques.

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