As Sess Ment of En Vi Ron Men Tal Gamma Dose in North Ern Rechna Doab, Pakistan 57 the Northeas T

56 Nu clear Tech nol ogy & Ra di a tion Pro tec tion –1/2009 AS SESS MENT OF ENVI RON MEN TAL GAMMA DOSE IN NORTH ERN RECHNA DOAB IN PA KI STAN by Abdul JABBAR1,2, Arshad S. BHATTI1, Syed S. AHMAD2, Waheed ARSHED2, and Perveen AKHTER2 Received on Febru ary 18, 2009; accepted in revised form on March 27, 2009 En vi ron men tal gamma ra di a tion lev els in north ern Rechna Doab, Pa ki stan, were mea - sured as a part of sys tem atic study aimed at the es tab lish ment of the back ground data base of ra di a tion and ra dio ac tiv ity lev els. The mea sure ments re ported in this pa per were made with por ta ble ra di a tion mon i tor which em ployed GM tube and was cal i - brated against sec ond ary stan dard do sim e try sys tem. The av er age ab sorbed dose rate in air was deter mined to vary from 86.0 nGy/h to 139.1 nGy/h with the mean value of 109.1 nGy/h. The an nual ef fec tive dose re mained within the range of 105.47 mSv to 170.54 mSv with its av er age value of 133.73 mSv. These en vi ron men tal ra di a tion doses in the area were com pa ra ble with those re ported for other coun tries. It was con cluded that the prev a lent ra di a tion lev els did not pose any sig nif i cant ra dio log i cal health haz - ard to the pop u lation. Key words: en vi ron men tal ra di a tion, gamma ra di a tion, ra di a tion mon i tor ing, gamma dose, Rechna Doab INTRODUCTION Punjab consis ts mostly of plains north and south of the an cient Salt Range, which stretch from east to The province of Punjab com prises eight ad- west. Punjab can be di vided into five major physi cal min is tra tive di vi sions ex tend ing over an area of regions: (I) Northern Moun tains, (II) South-West ern 205.346 sq. km (97.192 sq. miles). Ac cording to the Moun tains, (III) Potohar Platea u, (IV) the Upper Indus result s of 1998 census, the popu lati on of the prov- Plain, and (V) the Deserts. In the north, there are the ince stands at 71.5 mil lion (about 55% of the total outer ranges of the Hi ma layas: Murree and Kahuta pop u la tion of Pa ki stan) com pared with 47.12 mil - hills in the north and the Pubbi hills of Gujrat in the lion of 1981 popu lati on census fig ures. The popu la- south [1]. tion densit y in the prov ince is about 348 per sons per Ag ri cul ture is the most im por tant in dus try in sq. km. The province of Punjab is the most popu lous Punjab. Wheat, rice, sug arcane , fruit, tobacc o, cot ton, one, and therefore the as sess ment of radi a ti on doses and many other crops flourish in the soil of Punjab. is a rel a tively im por tant is sue. The province of Punjab is criss-crossed by ca nals as a result of which the area is now a huge oasis where there are hun dreds of new settlements. Nu clear Tech nol ogy & Ra di a tion Pro tec tion Sci en tific pa per UDC: 539.166:614.87 Study area BIBLID: 1451-3994, 24 (2009), 1, pp. 56-60 DOI: 10.2298/NTRP0901056J The Rechna Doab can be clas si fied as one of the 1 De part ment of Phys ics, main regions of Punjab. Plain areas of Punjab are di - COMSATS In sti tute of In for ma tion Tech nol ogy, Islamabad, Pa ki stan vided into nat u ral regions based on its vari ous rivers, 2 Health Phys ics Di vi sion, since the name Punjab is based on its 5 main rivers. Pa ki stan In sti tute of Nu clear Sci ence & En gi neer ing (PINSTECH), Rechna Doab, com prising about 28.500 square kilo - Nilore, Islamabad 45650, Paki stan me ters, is en closed by the river Chenab and river Ravi E-mail ad dress of cor re spond ing au thor: on the northwest and south east, re spec tively, with the mand_tegha@ya hoo.com (A. Jabbar) piedm onts near the Jammu and Kash mir boundary in A. Jabbar, et al.: As sess ment of En vi ron men tal Gamma Dose in North ern Rechna Doab, Pakistan 57 the northeas t. Its longi tude is 71o 48' to 75o 20' E and Ex ter nal ex po sures out doors arise from ter res- lat i tude 30o 31' to 32o 51' N. Rechna Doab is about trial radionuclides pres ent at trace lev els in all soils 403 km long in southwest direc ti on and has a maxi - and from cosm ic radi a ti ons. The specif ic levels in soils mum width of about 113 km [2]. are re lated to the types of rocks from which the soils The area is interfluvial and is southwest erly orig i nate. Higher ra di a tion lev els are as so ci ated with sloped. In the up per part of the Rechna Doab, the slope igne ous rocks, such as granit e, and lower levels with is about 380 cm/km to about 9 cm/km [3]. Physio- sed i men tary rocks. There are ex cep tions, how ever, as graph i cally, the Rechna Doab can be char ac ter ized by some shales and phosphate rocks have a rela ti vely the fol low ing units: high content of radionuclides. Many surveys have – Kirana hills – though minor when com pared with been made to deter mine the back ground lev els of the allu vial com plex, but very prom inent, radionuclides in soils, which can in turn be relat ed to – ac tive flood plains in the vi cin ity of the rivers the ab sorbed dose rates in air. The later can eas ily be Ravi and Chenab, mea sured di rectly, and the re sults of such measure - – abandoned flood plain, and ments provide an even more exten sive eval u ati on of – bar upland – an ele vate d land be yond the reach of the back ground ex po sure lev els in dif fer ent coun tries flood wa ters of the rivers. [6]. The cos mic ex po sure which is the secret com po - nent of the background radi a ti on dose is relat ed to the al ti tude of the place of in ter est. Geology Gamma dose measure ments have been con - ducted in dif ferent ar eas of the country through soil The con sol i dated ex posed rocks near Chiniot, radionuclides, but not in a sys tematic way. Like the Sangla, and Shahkot repre sent the rem nants of the bur- large-scale surveys done in many other countri es of ied ridge of meta mor phic or igne ous rocks form ing the the world, this first sys tematic and ex ten sive study of base ment of the al lu vial de pos its in Rechna Doab. this nature was done by using a cali brat ed dose rate These indurated rocks are known as Kirana hills and me ter which gives in stan ta neous results. are of the pre cam brian age. These rocks cover the cen - The objec ti ve of the pres ent study was to develop tral part of Rechna Doab making the longi tudi nal sec - the base line natu ral background radi a ti on dose data for tion across its width. The uncon sol i date d allu vial de- var i ous re gions of north ern Rechna Doab, com prising pos its are of the pleis to cene to re cent in age and are dis tricts Sialkot, Gujranwala, Narowal, and Hafizabad. overly ing the precam brian base ment rock. These were A detai led radi a ti on survey was made by using a quite depos it ed in a subsid ing trough by the ances tral and sen si tive and well cal i brated ra di a tion dose rate me ter. pres ent trib u tar ies to the river Indus. The al lu vial fill is For unknown measure m ent patter n the northern more or less hom o geneous in nature , and has littl e con- Rechna Doab was di vided into grids of 24 ´ 28 sq. km, ti nu ity ver ti cally or lat er ally, in di cat ing di verse cover ing the whole area under the study. The re sults depositional envi ron ments from time to time caused have been prepared and present ed in this pa per. by con stant change in the stream courses [4]. The al lu vial sed i ments con sist mainly of gray, gray ish brown, fine to medium sand, silt, and clay. MATERIALS AND METHODS Gravel or very coarse sand is uncom mon. Kankers, a cal ciumcar bon ate ma te rial of sec ond ary or i gin is as so - Ra dio log i cal mon i tor ing was per formed by us ing ci ated with fine-grained strata.

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