Natural radionuclides in fish species from surface water of Bagjata and Banduhurang uranium mining areas,East Singhbhum,Jharkhand, India

Purpose:?To study the natural radionuclides in the freshwater fish samples around the uranium mining areas of Bagjata and Banduhurang, East Singhbhum, Jharkhand, India

Materials and methods:?The naturally occurring radioisotopes of uranium, U(nat), consisting of ²³⁴U, ²³⁵U and ²³⁸U; ²²⁶Ra, ²³⁰Th and ²¹⁰Po were analysed in the fish samples from the surface water of Bagjata and Banduhurang mining areas after acid digestion. The ingestion dose, concentration factor and excess lifetime cancer risk of the radionuclides were estimated.

Results:?The geometric mean activity of U(nat), ²²⁶Ra, ²³⁰Th and ²¹⁰Po in the fish samples was found to be 0.05, 0.19, 0.29 and 0.95 Bq kg^?1_fresh (Becquerel per kilogram fresh fish), respectively, in the Bagjata mining area, while for Banduhurang mining area it was estimated to be 0.08, 0.41, 0.22 and 2.48 Bq kg^?1_fresh, respectively. The ingestion dose was computed to be 1.88 and 4.16?μSvY^?1, respectively, for both the areas which is much below the 1 mSv limit set in the new International Commission on Radiological Protection (ICRP) recommendations. The estimation of the Concentration Factors (CF) reveal that the CF from water is greater than 1 l/kg^?1in most of the cases while from sediment CF is less than 1. The excess individual lifetime cancer risk due to the consumption of fish was calculated to be 2.53?×?10^?5 and 6.48?×?10^?5, respectively, for Bagjata and Banduhurang areas, which is within the acceptable excess individual lifetime cancer risk value of 1?×?10^?4.

Conclusion:?The study confirms that current levels of radioactivity do not pose a significant radiological risk to freshwater fish consumers.     

Dose estimates for the local inhabitants from 210Po ingestion via dietary sources at a proposed uranium mining site in India

Abstract

Purpose: To study the distribution of ²¹⁰Po activity in food in Bagjata in East Singhbhum, India.

Materials and methods: ²¹⁰Po were analyzed in the food samples of plant origin such as cereals, pulses, fruits, vegetables and food of animal origin such fish, chicken, egg, etc., in and around Bagjata uranium mining area as a part of baseline study after acid digestion. The intake and ingestion dose of the radionuclide was estimated.

Results: The general range of ²¹⁰Po activity in all the dietary components ranged widely from <0.2–36 Bqkg^-1_fresh. In the food of plant origin, the minimum activity of ²¹⁰Po was estimated in vegetables while maximum in pulses. In food of animal origin, the observed minimum activity of ²¹⁰Po was in eggs and the maximum observed was in chicken samples. The intake of ²¹⁰Po considering all dietary components was found to be 464 Bq.Y^-1 while the ingestion dose was calculated to be 557 μSv.Y^-1, respectively. The estimated doses are reflecting the natural background dose via the route of ingestion, which is much below the 1 mSv limit set in the International Commission on Radiological Protection (ICRP) recommendations.

Conclusion: The study confirms that current levels of ²¹⁰Po do not pose a significant radiological risk to the local inhabitants.     

226Ra 228Ra 210Pb和210Po在水生生物及食物链中转移规律的探讨

目的 为了解天然放射性核素²²⁶Ra、²²⁸Ra、²¹⁰Pb与²¹⁰Po在水生物及食物链中转移和蓄积情况。方法 定点采集养殖水产品及栖息环境中水与底质沉积物, 按不同的实验需要, 每个鲜样分别剥取肉, 骨(壳),鳞片和胃肠。烹饪样品, 洗净、称重、清炖, 熟后分离出骨(壳),余为食物。样品分别测定²²⁶Ra、²²⁸Ra、²¹⁰Pb和²¹⁰Po含量。数据按统计学要求处理, 配对数据, 作了配对显着性检验。结果 ²²⁶Ra、²²⁸Ra和²¹⁰Pb主要沉积于骨(壳)中, 浓集系数为10²～10³,肉中为10⁰～10².²¹⁰Po主要蓄积在水生物胃肠中, 浓集系数在10²～10⁴,鱼类胃肠与贝类肉中可达10⁴.水产食品烹饪加工过程²²⁶Ra、²²⁸Ra和²¹⁰Pb在食物链中转移不明显, 经配对显着性检验, 差异无显着性(P0.05);然而210Po在淡水鱼类和虾类中转移是明显的, 肉配对检验有非常显着性差别(P<0.01).结论水生物对²²⁶Ra、²²⁸Ra、²¹⁰Pb和²¹⁰Po有很强浓集能力。     

Concerning ionizing radiation-induced cancer from internally deposited radionuclides

Purpose: A comparative evaluation was conducted of ionizing radiation-induced cancer from internally deposited radionuclides.

Materials and methods: Data were evaluated for humans for ²²⁶Ra, and for laboratory animal studies for alpha-emitters ²²⁸Ra, ²²⁶Ra, ²²⁴Ra, ²³⁸Pu, ²³⁹Pu, ²²⁸Th, ²⁵²Cf, ²⁴⁹Cf, and ²⁴¹Am, and for beta-emitters ⁹⁰Sr, ⁹⁰Y, ⁹¹Y, and ¹⁴⁴Ce. Intake routes included ingestion, inhalation, and injection.

Results: Cancer risk associated with protracted ionizing radiation exposure is a non-linear function of lifetime average dose rate to the affected tissues. The lifetime effects are best described by three-dimensional average-dose-rate/time/response surfaces that compete with other causes of death during an individual's lifetime. At the higher average dose rates the principal deleterious effects are those associated with radiation-induced injury, while at intermediate average dose rates radiation-induced cancer predominates.

Conclusions: The cumulative radiation dose is neither an accurate nor an appropriate measure of cancer risk associated with protracted ionizing radiation exposure. At low average dose rates the long latency time required for radiation-induced cancer may exceed the natural lifespan yielding a lifespan virtual threshold for radiation-induced cancer for cumulative doses below about 5–10 Sv for bone, bone marrow and lungs.     

Spatial Distribution of Naturally Occurring 210Po and 226Ra in Children's Teeth

Deciduous and permanent teeth extracted from juveniles for orthodontic purposes have been analysed using α-sensitive plastic track detectors for the spatial distribution of total α-activity and naturally occurring ²¹⁰Pb-supported ²¹⁰Po and ²²⁶Ra. The distribution of these radionuclides is nonuniform, with ²¹⁰Po being primarily associated with outer enamel and ²²⁶Ra with the pulp. The observations suggest that ²¹⁰Pb/²¹⁰Po concentrates at the interface of enamel with saliva or blood, by means of unidirectional ionic exchange with calcium. In contrast, ²²⁶Ra concentrates in the predentine band at the interface with pulp and with systemic blood circulation, where its uptake is permitted by the incomplete calcification in this band. Activity concentration was measured in 900 teeth. Total concentration on the outer enamel surface of deciduous teeth, permanent teeth from children ?10 years and permanent teeth from children > 10 years give respective mean values of 8·63±0·26, 5·76±0.48 and 7·00±0·15 Bq kg^?1. ²²⁶Ra concentration on the corresponding longitudinal sections comprising pulp, dentine and annular enamel give respective mean values of 0·715±0·055, 0·418±0·083 and 0·514±0·029 Bq kg^?1. Mean activity concentration in 32 foetal teeth was 2·05±0·31 Bq kg^?1. The results form the basis of more detailed studies of (1) age-dependent uptake of α-radionuclides in teeth and their microdistribution, and (2) the geographical variation in activity concentration with respect to environmental factors such as domestic radon exposure.     

Chronic exposure by ingestion of environmentally relevant doses of 226Ra leads to transient growth perturbations in fathead minnow (Pimephales promelas,Rafinesque, 1820)

Abstract

Purpose: To assess the impact of environmentally relevant levels of ingested ²²⁶Ra on a common freshwater fish species.

Methods: Fathead minnow (Pimephales promelas, Rafinesque) were obtained at the first feeding stage and established on a commercial fish food diet containing ²²⁶Ra in the activity range 10 mBq/g^?1, –10,000 mBq/g^?1. They remained on this diet for 24 months and were sampled invasively at 1,6,18 and 24 months to assess growth, biochemical indices and accumulated dose and non-invasively also at 12 and 15 months to assess growth.

Results: Fish fed 10 and 100 mBq/g^?1 diet showed a small transitory deregulation of growth at 6 and 12 months. Fish fed higher activities showed less significant or insignificant effects. There was a trend at 18 months which was stronger at 24 months for the population distribution to change in all of the ²²⁶Ra fed groups so that smaller fish were smaller and bigger fish were bigger than the controls. There were also significant differences in the ratios of protein:DNA at 24 months which were seen as a trend but were not significant at earlier time points.

Conclusions: Fish fed a radium diet for 2 years show a small and transitory growth dysregulation at 6 and 12 months. The effects predominate at the lower activities suggesting hormetic or homeostatic adjustments. There was no effect on growth of exposure to the high activities ²²⁶Ra. This suggests that radium does not have a serious impact on the ecology of the system and the level of radium that would be transferred to humans is very low. The results may be important in the assessment of long-term environmental impacts of ²²⁶Ra exposure.     

EC comparison on the determination of 226Ra, 228Ra, 234U and 238U in water among European monitoring laboratories

In anticipation of new European requirements for monitoring radioactivity concentration in drinking water, IRMM organized an interlaboratory comparison on the determination of low levels of activity concentrations (about 10–100 mBq L^?1) of the naturally occurring radionuclides ²²⁶Ra, ²²⁸Ra, ²³⁴U and ²³⁸U in three commercially available mineral waters. Using two or three different methods with traceability to the International System of Reference (SIR), the reference values of the water samples were determined prior to the proficiency test within combined standard uncertainties of the order of 3%–10%. An overview of radiochemical separation and measurement methods used by the 45 participating laboratories are given. The results of the participants are evaluated versus the reference values. Several of the participants’ results deviate by more than a factor of two from the reference values, in particular for the radium isotopes. Such erroneous analysis results may lead to a crucial omission of remedial actions on drinking water supplies or to economic loss by an unjustified action.     

The effect of uranium migration on radionuclide distributions for soil samples at the El-Gor area,Sinai, Egypt

The concentrations and distributions of the activity of natural radionuclides in soil samples were investigated in fifteen soil samples at El-Gor area representing two profiles (A and B) using a HP–Ge detector and alpha counting by SSNTD (CR-39), respectively. The average concentrations of the radionuclides ²³⁸U, ²²⁶Ra, ²³⁵U, ²³²Th and ⁴⁰K are 203.4, 177.23, 9.77, 43.33 and 386.22 Bq kg⁻¹ (dry weight), respectively, and profile A and ²³⁸U, ²²⁶Ra, ²³⁵U, ²³²Th and ⁴⁰K have average concentrations of 232.58, 246, 11.7, 31.7, and 277.07 Bq kg⁻¹ for profile B, respectively. The eTh and eU were estimated to detect the migration process of uranium into or out of an area or uranium to or from the studied profiles. The results indicate a migration of uranium by 29% for profile A and 65.37% for profile B. The activity ratio (²³⁸U/²²⁶Ra) was found to be 0.9 in profile A and 1.15 in profile B. These ratios coincide with the uranium migration processes. The responsible mass corresponding to the measured ²²⁶Ra activity was also calculated. The radon activity concentrations for the two profiles are nearly 300 Bq m⁻³. The emanation coefficient (η) was calculated from the ratio of the expected radon activity to the measured radon for the studied soil samples. The value of η was found to depend only on the radium activity regardless to soil formation.     

Natural radioactivity in tap water and associated age-dependent dose and lifetime risk assessment in Amman, Jordan

With the aim of assessing potential public impact, preliminary investigations on tap waters collected from highly populated areas in Amman and Aqaba, Jordan were conducted by measuring gross alpha and beta activities as well as uranium and radium radionuclides. Gross activities deduced by liquid scintillation counting (LSC) were ranged in <50-250±23 mBq l⁻¹ for alpha and <188-327±29 mBq l⁻¹ for beta in Amman whereas higher concentrations were found in Aqaba. The results show that gross β activities are generally higher than the corresponding gross α activities and direct correlations between gross activities and total dissolved solids (TDS) exist. Moreover, the effect of TDS on gross analyses was studied and devoted to the optimization of LSC parameters. ²³⁴U, ²³⁵U and ²³⁸U concentrations were determined by alpha spectrometry after separation from the matrix by extraction chromatography and electroplating. ²²⁶Ra and ²²⁸Ra concentrations were measured, respectively, using de-gassing and gas proportional counter techniques. Uranium and radium concentrations do not reach the WHO recommended levels and the radioisotopic activity ratios were discussed. The associated age-dependent dose from water ingestion in Amman was estimated. The total dose for adults had an average value of 0.15 mSv y⁻¹, which exceeds the WHO recommended limit of 0.1 mSv y⁻¹ but still below the Jordanian limit of 0.5 mSv y⁻¹. Although the Jordanian limit was exceeded for babies and infants, the lifetime risk assessment showed values as low as 10⁻⁴. Thereby it is concluded that tap waters of Amman is radiologically safe and pose no significant hazard to the public. Finally, a comparison of the investigated waters with worldwide data was made.     

Radium-226 concentration in spring water sampled in high radon regions

Water ²²⁶Ra concentration in springs was measured in regions with high indoor radon: Ural, North Caucasus (Russia), Niska Banja (Serbia), Piestany (Slovakia), and Issyk-Kul (Kyrgyzstan). This paper presents the results for ²²⁶Ra concentration above 0.03 Bq l^–1. Radium in water could indicate indoor radon problem in the region and water investigation is useful at the initial stage of radon survey. Even low ²²⁶Ra concentration in water (0.1–0.6 Bq l^–1) caused high ²²⁶Ra activity in travertine (up to 1500 Bq kg^?1), which resulted in indoor radon concentration above 2000 Bq m^?3 (Niska Banja).     

Calibration of the direct LSC method for radon in drinking water: Interference from 210Pb and its progenies accumulated in 226Ra standard solution

The standard ASTM method is the most commonly applied method for determining ²²²Rn in drinking water. The method is calibrated with a ²²⁶Ra standard solution that usually contains variable amounts of ²¹⁰Pb, ²¹⁰Bi and ²¹⁰Po if the standard has not recently been purified. Until now it has not been experimentally confirmed that these progenies do not interfere when the method is calibrated. In this study, interference was examined using three different organic cocktails and α/β liquid scintillation spectrometry to separately assess the effect of three radionuclides. The interference from ²¹⁰ Po was 4% for one of the cocktails if the ²²⁶Ra standard had been purified 5 years earlier. The interferences from ²¹⁰Pb and ²¹⁰Bi were negligible compared to that of ²¹⁰Po.     

Morphological features of the microdistribution of naturally occurring 210Pb/210Po and 226Ra in the teeth of children and juveniles

Purpose: To examine the microdistribution of natural α‐radioactivity in deciduous teeth of children and the permanent teeth of juveniles extracted for orthodontic purpose from across the UK.

Materials and methods: The microdistribution of ²¹⁰Pb‐supported ²¹⁰Po and ²²⁶Ra in 708 deciduous and permanent teeth and 32 foetal teeth was measured on 1442 TASTRAK α‐particle track detectors.

Results: Of the various findings, a number are of special interest. Around half of the ²¹⁰Pb activity in the outer enamel of deciduous teeth appears to have been acquired in utero as a result of transplacental transfer. In deciduous and permanent teeth, ²²⁶Ra is concentrated mainly in the circumpulpal region, while the highest levels of ²¹⁰Po are on the highly calcified outer enamel surface. Furthermore, activity concentrations recorded on this surface were ln‐normally distributed.

Conclusions: ²¹⁰Pb‐supported ²¹⁰Po activity on the outer enamel surface of permanent teeth constitutes an assay of cumulative environmental exposure with which to assess exposure in bone, both in utero and in childhood. Such assessment can be used to study geographical variations in the α‐activity in teeth. More work is also required to determine the concentrations of both ²¹⁰Po and ²¹⁰Pb in the foetal skeleton.     

The natural radioactivity in Guarani aquifer groundwater, Brazil.

The measurements of gross alpha and gross beta radioactivity in groundwater samples from Guarani aquifer in Brazil are reported in this paper together with the activity concentration of the natural dissolved radionuclides (40)K, (238)U, (234)U, (226)Ra, (222)Rn, (210)Po, (210)Pb, (232)Th, (228Th), and (228)Ra. Most of the gross alpha radioactivity values were below the critical level of detection corresponding to 1mBq/L, however, the whole data set for the gross beta radioactivity and radionuclides (40)K, (238)U, (234)U, (226)Ra, (222)Rn, (210)Po, (210)Pb, and (228)Ra was submitted to a statistical treatment, considering class intervals arranged in geometric progression, because of the great variability of the activity. The analysis indicated lognormal distribution of the data, as usually observed in samples taken from the natural context. An inverse relationship between the gross alpha and gross beta activity has been identified and is related to an increase in the K content in the water. The mobility coefficient has been estimated for (238)U, (226)Ra, (232)Th and (228)Ra in Guarani aquifer and the results indicated that the radioelement solubility in the studied system varies according to the following order: radium>uranium>thorium. The implications of the data obtained in terms of standards established for defining the drinking water quality have also been discussed.     

Estimation of radiation doses to members of the public in Italy from intakes of some important naturally occurring radionuclides (238U, 234U, 235U, 226Ra, 228Ra, 224Ra and (210)Po) in drinking water.

The radiological quality in some samples of drinking water collected in Italy has been evaluated in the paper. As far as the measured alpha or beta radionuclides are concerned, the doses for all the analysed samples of drinking water are in the range of 1.80-36.2microSvyr(-1), all being well below the reference level of the committed effective dose (100microSvyr(-1)) recommended by the WHO. As far as each measured alpha or beta radionuclide is concerned, the dose contributions for most of the analysed water samples are in this order: 210Po228Ra>226Ra>234U238U>224Ra>235U, and (210)Po and (228)Ra can yield a significant contribution to the doses from the analysed drinking water samples. As far as the elements are concerned, the dose contributions are 48.0+/-27.9% from radium, 31.7+/-23.1% from polonium, and 20.3+/-14.1% from uranium. The water samples, No. 2, 7, 13, and 15, can lead to a dose of >10microSvyr(-1), mainly due to the dose contribution from (210)Po and 228Ra, especially water samples No. 2 and 13. The obtained data can provide basic information for consumers and competent authorities regarding the internal exposure risk due to drinking water intake, and can possibly serve as a comparison when evaluating the dose contribution from artificial radionuclides released to the environment as a result of any human practices and accidents in the studied area.     

Assessment of natural radioactivity levels and radiation hazards due to cement industry

The cement industry is considered as one of the basic industries that plays an important role in the national economy of developing countries. Activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in Assiut cement and other local cement types from different Egyptian factories has been measured by using γ-ray spectrometry. From the measured γ-ray spectra, specific activities were determined. The measured activity concentrations for these natural radionuclides were compared with the reported data for other countries. The average values obtained for ²²⁶Ra, ²³²Th and ⁴⁰K activity concentration in different types of cement are lower than the corresponding global values reported in UNSCEAR publications. The obtained results show that the averages of radiation hazard parameters for Assiut cement factory are lower than the acceptable level of 370 Bq kg^?1 for radium equivalent Ra_eq, 1 for level index Iγr, the external hazard index Hex ≤1 and 59 (nGy h^?1) for absorbed dose rate. The manufacturing operation reduces the radiation hazard parameters. Cement does not pose a significant radiological hazard when used for construction of buildings.     

Natural radioactivity in underground water from the Outer Carpathians in Poland with the use of nuclear spectrometry techniques

The investigations of natural radioactivity in underground mineral water and spring water in health resorts in the Outer Carpathians were performed. Samples from 40 water springs were collected 3–4 times over a period of 10 years (1997–2007). In order to obtain necessary data, two different nuclear spectrometry techniques were applied: WinSpectral α?β 1414 liquid scintillation counter from Wallac and α-spectrometer 7401 VR from Canberra–Packard, USA with the silicon surface barrier detector. The activity concentrations of ²²²Rn in the investigated samples varied from below 1 to 50 Bq/l. For radium isotopes the concentrations were in a range from below 10 to 490 mBq/l for ²²⁶Ra and from 29 to 397 mBq/l for ²²⁸Ra. The highest concentrations for both radium isotopes were obtained for medicinal water Zuber III from Krynica spa. The activity concentrations for uranium isotopes varied from below 0.5 to 16 mBq/l for ²³⁸U and from below 0.5 to 162 mBq/l for ²³⁴U with the highest values obtained for water Zuber IV. The highest annual effective dose arising from mainly radium isotopes was obtained for Zuber III water and was equal to 75 μSv/yr. Additionally, the annual effective doses due to ²²²Rn consumed with water were also estimated. The isotopic ratios between isotopes originating from the same decay chain (²³⁴U/²³⁸U, ²²⁶Ra/²³⁸U) and from different radioactive decay chains (²²⁶Ra/²²⁸Ra) were determined. The correlations between different isotopes were presented.     

Enrichment and vertical profiles of 210Po and 210Pb in monazite areas of coastal Karnataka

A study on radiation level and radionuclide distribution in the environment of coastal Karnataka has revealed the presence of low-level monazite deposit in the Ullal beach area. The paper presents systematic studies on the distribution, enrichment and vertical profiles of ²¹⁰Po and ²¹⁰Pb, important daughter products of ²³⁸U, in Ombattu Kere, Summer Sand and the Bhagavathi Temple region of the Ullal beach area of coastal Karnataka. Sand samples collected at different depths from these locations were analyzed for ²¹⁰Po and ²¹⁰Pb activities to understand the distribution, enrichment and vertical profiles of these radionuclides in monazite area. The activity of ²¹⁰Po in the Ullal region is found to vary from 1.7 to 43.2 Bq kg^?1 with a mean value of 11.2 Bq kg^?1 and that of ²¹⁰Pb varies from 1.0 to 66.7 Bq kg^?1 with a mean value of 19.1 Bq kg^?1. The mean ²¹⁰Po/²¹⁰Pb ratio was observed to be 0.6. The absorbed gamma dose rate in the region varies in the range 39–460 nGy h^?1 with a mean value of 193 nGy h^?1.     

Relationship between radioactivity of radium and concentrations of barium and lead in hokutolite

Hokutolite consists of barite (BaSO₄) and anglesite (PbSO₄), and contains significant amounts of radium isotopes as a radioactive mineral. Photon activation and gamma-ray spectrometry were employed to determine Ba, Pb and ²²⁶Ra contents in hokutolite samples and to investigate the correlation between ²²⁶Ra activity and both Ba and Pb content. ²²⁶Ra activity in 30 hokutolite samples were estimated in the range of 40–65 Bq/g and was positively related to Ba content (r=0.859, p<0.001), but independent of Pb content (r=−0.236, p=0.217). Experimental results implied that ²²⁶Ra preferably precipitated with Ba over Pb. The ²²⁶Ra activity in hokutolite from the Peitou Hot Spring was experimentally estimated based on the Ba/Pb ratio and expressed as ²²⁶Ra (Bq/g)=14.67 (Ba/Pb)_molar+14.13.     

Stem Cells in Bone and Bone Marrow after Contamination with Bone-seeking Radionuclides

Summary

The effects of time, mass and oxidation state on plutonium gastrointestinal absorption and tooth adsorption were studied during and after chronic ingestion of plutonium-238 (IV) or (VI) (1·55–15·60 kBq/ml) in 6·5 mm bicarbonate medium by fed rats via drinking water for 8 days to 3 months. Animals were killed during the ingestion to follow the kinetics of whole-body storage and clearance of plutonium. At 1·55 kBq/ml the amount of plutonium retained in the skeleton increased continuously during the 85 days of ingestion and reached a plateau thereafter. This plutonium retention was therefore dependent on the total mass administered but not proportional to this mass, as the fraction of administered plutonium retained decreased during the first 22 days of ingestion and then stabilized. This is reflected by the gastrointestinal transfer (f₁), which had risen to (3·80 ± 0·82) × 10^?5 on Day 3 of ingestion and then decreased to a stabilized value of (1·07 ± 0·06) × 10^?5 from Day 30 to the end of the ingestion period. In the liver, the amount of plutonium retained reached a plateau, which lasted from Day 30 to the end of ingestion. The kidneys and spleen were also found to be retention sites. By Day 3 of ingestion, for a mass ingested of 5 × 10^?7 g/kg of body mass, the maximum mean value of f₁ we found was smaller than the 10^?4 recommended by ICRP Report 30. The oxidation state had no effect on f₁. Large plutonium deposition was observed on the teeth. For both oxidation states (IV) and (VI), about 0·10% of the administered dose was deposited on the teeth after 3 days of ingestion, whatever the plutonium concentration administered. However, whereas the amount of plutonium (IV) deposited did not change throughout the ingestion period, tooth deposition of plutonium (VI) decreased.     

Impact of phosphate industry on the environment: a case study.

This paper presents results obtained from studying the impact of the Syrian phosphate industry on the environment. This work is based on evaluating naturally occurring radionuclide concentrations in the surrounding environment at the locations of this industry, viz. mines, phosphate fertilizers factory and phosphate export platforms. Air particulates, soil, water (river, lake and sea water), biota and plant samples were collected and analyzed. Natural radionuclides ((226)Ra, (nat)U, (210)Po, (210)Pb) were determined by means of low background gamma spectrometry and alpha spectrometry. The results showed that the distribution and enhancement of natural radionuclides in the surrounding environment in these three locations are mainly due to fallout of phosphate dust generated during loading and processing of phosphate ore. The extent of contamination was related to climate conditions. Radon gas and its daughters generated from phosphate ores were found to be the main source of enhanced concentrations of (210)Po and (210)Pb in soil and leafy plants. These results can be considered as baseline data and can be used to prove the effectiveness of any future pollution controls adopted.