Natural radioactivity and radiation exposure in the high background area at Chhatrapur beach placer deposit of Orissa, India

Variation in alpha radioactivity of plants with the use of different fertilizers and radon measurement in fertilized soil samples

BACKGROUND

People are exposed to ionizing radin from the radionuclides that are present in different types of natural sources, of which phosphate fertilizer is one of the most important sources. Fertilizers are commonly used in agricultural field worldwide to enhance the crop yield.

MATERIALS AND METHODS

In the present investigation, a control study was carried out on the lady's finger plants grown in earthen pots. To observe the effect of fertilizers their equal amounts were added to the soil just before the plantation. The alpha track densities were measured using solid state nuclear track detectors (SSNTDs), a sensitive detector for alpha particles.

RESULTS

The measured alpha track densities (T cm(-2)d(-1)) in lady's finger plants on top and bottom face of leaves after 30, 50 and 70 days of plantation varied from 49 ± 11 to 206 ± 2.6, 49 ± 16 to 248 ± 16 and 57 ± 8.5 to 265 ± 32 respectively in various leaf samples.

CONCLUSIONS

The alpha track densities were found to vary with nature of fertilizers added to the soil and an increase was also observed with time. The alpha track densities were also measured in soil samples mixed with different fertilizers. The radon exhalation rates in various soil samples and soil to plant transfer factor (TF) of alpha tracks were also calculated.

The effect of high level natural ionizing radiation on expression of PSA, CA19-9 and CEA tumor markers in blood serum of inhabitants of Ramsar, Iran

Since several high level natural radiation areas (HLNRAs) exist on our planet, considerable attention has been drawn to health issues that may develop as the result of visiting or living in such places. City of Ramsar in Iran is an HNLRA, and is a tourist attraction mainly due to its hot spas. However, the growing awareness over its natural radiation sources has prompted widespread scientific investigation at national level. In this study, using an ELISA method, the level of expression of three tumor markers known as carcinoembryonic antigen (CEA), prostate-specific antigen (PSA) and carcino antigen 19-9 (CA19-9) in blood serum of 40 local men of Ramsar (subject group) was investigated and compared to 40 men from the city of Noshahr (control group). Noshahr was previously identified as a normal level natural radiation area (NLNRA) that is some 85 km far from Ramsar. According to statistical analysis, there was a significant difference in the levels of PSA and CA19-9 markers between the two groups (p < 0.001) with those of Ramsar being considerably higher. CEA level did not show any difference. Although some of the volunteers tested positive to the markers, they were in good health as confirmed by the physician. Moreover, the high number of positive markers in Noshahr was considerable. Therefore, future study is needed to further validate this result and to determine the level of positivity to tumor markers in both cities.

Natural radionuclide and radiological assessment of building materials in high background radiation areas of Ramsar, Iran

Building materials, collected from different sites in Ramsar, a northern coastal city in Iran, were analyzed for their natural radionuclide contents. The measurements were carried out using a high resolution high purity Germanium (HPGe) gamma-ray spectrometer system. The activity concentration of (226)Ra, (232)Th, and (40)K content varied from below the minimum detection limit up to 86,400 Bqkg(-1), 187 Bqkg(-1), and 1350 Bqkg(-1), respectively. The radiological hazards incurred from the use of these building materials were estimated through various radiation hazard indices. The result of this survey shows that values obtained for some samples are more than the internationally accepted maximum limits and as such, the use of them as a building material pose significant radiation hazard to individuals.

Ingestion dose from 238U, 232Th, 226Ra, 40K and 137Cs in cereals, pulses and drinking water to adult population in a high background radiation area, Odisha, India

A natural high background radiation area is located in Chhatrapur, Odisha in the eastern part of India. The inhabitants of this area are exposed to external radiation levels higher than the global average background values, due to the presence of uranium, thorium and its decay products in the monazite sands bearing placer deposits in its beaches. The concentrations of (232)Th, (238)U, (226)Ra, (40)K and (137)Cs were determined in cereals (rice and wheat), pulses and drinking water consumed by the population residing around this region and the corresponding annual ingestion dose was calculated. The annual ingestion doses from cereals, pulses and drinking water varied in the range of 109.4-936.8, 10.2-307.5 and 0.5-2.8 µSv y(-1), respectively. The estimated total annual average effective dose due to the ingestion of these radionuclides in cereals, pulses and drinking water was 530 µSv y(-1). The ingestion dose from cereals was the highest mainly due to a high consumption rate. The highest contribution of dose was found to be from (226)Ra for cereals and drinking water and (40)K was the major dose contributor from the intake of pulses. The contribution of man-made radionuclide (137)Cs to the total dose was found to be minimum. (226)Ra was found to be the largest contributor to ingestion dose from all sources.

Radioactivity of beach sand in the south western coast of Sri Lanka

The activity concentrations and effective dose rates due to (232)Th, (238)U and (40)K were determined for sand samples collected along the coastal strip from Crow Island to Beruwala, a part of south western coast of Sri Lanka, using a high-purity germanium detector. The ranges and the mean activity concentrations measured were (11-19 600, 2100), (7-3150, 450) and (14-1210, 220) Bq kg(-1) for (232)Th, (238)U and (40)K, respectively. The effective annual gamma dose in the area ranged from 0.004 to 16.8 mSv y(-1). For 21 % of the locations, the annual effective dose determined from the activity concentrations exceeded the average worldwide exposure of 2.4 mSv y(-1).

Natural radionuclide concentrations in processed materials from Thai mineral industries

The naturally occurring radioactive materials (NORMs) distributed in products, by-products and waste produced from Thai mineral industries were investigated. Samples were analysed for radioactivity concentrations of two principal NORM isotopes: (226)Ra and (228)Ra. The enrichment of NORM was found to occur during the treatment process of some minerals. The highest activity of (226)Ra (7 × 10(7) Bq kg(-1)) was in the scale from tantalum processing. The radium concentration in the discarded by-product material from metal ore dressing was also enriched by 3-10 times. Phosphogypsum, a waste produced from the production of phosphate fertilisers, contained 700 times the level of (226)Ra concentration found in phosphate ore. Hence, these residues were also sources of exposure to workers and the public, which needed to be controlled.

Elevated radionuclide concentrations in heavy mineral-rich beach sands in the Cox's Bazar region, Bangladesh and related possible radiological effects

The study focuses on elevated levels of environmental radioactivity present in heavy mineral deposits located along a 120-km coastal section of Cox's Bazar on the eastern panhandle of Bangladesh. The deposits are situated in or at sand dunes located on the recent beach (foredune area) or in attached paleo-beach areas (backdune area). This study investigates activity concentrations in bulk beach sands (six representative samples) and in five mineral fractions separated from the beach sands in order to assess potential radio-ecological effects and the possible use of the mineral deposits as a source for uranium and thorium. The bulk beach sands and individual mineral fractions were analysed by gamma-ray spectroscopy. The activity concentrations of U-238, U-235, Th-232 and K-40 in the bulk beach sand samples were found to be considerably high and positively correlated to the concentration of heavy minerals in the sand. In the mineral fractions, the highest activity concentrations were found in the zircon fraction followed by garnet, rutile, ilmenite and magnetite. The determination of (i) the radium activity, (ii) several radiation hazard indices and (iii) adsorbed and effective gamma doses allowed to assess the related exposure of the environment and the local population to elevated radioactivity. It becomes evident from the present data that (1) if raw sands or mineral fractions mined in the study area are used for building purposes or industrial use, their activity concentrations have to be considered from a radio-ecological perspective and (2) if mining and processing of the minerals is being considered, uranium and thorium may become strategically significant by-products.

Investigation of the environmental impacts of naturally occurring radionuclides in the processing of sulfide ores for gold using gamma spectrometry

The possible environmental impacts of naturally occurring radionuclides on workers and a critical community, as a result of milling and processing sulfide ores for gold by a mining company at Bogoso in the western region of Ghana, have been investigated using gamma spectroscopy. Indicative doses for the workers during sulfide ore processing were calculated from the activity concentrations measured at both physical and chemical processing stages. The dose rate, annual effective dose equivalent, radium equivalent activity, external and internal hazard indices, and radioactivity level index for tailings, for the de-silted sediments of run-off from the vicinity of the tailings dam through the critical community, and for the soils of the critical community's basic schools were calculated and found to be lower than their respective permissible limits. The environmental impact of the radionuclides is therefore expected to be low in this mining environment.

Radiological indices of technologically enhanced naturally occurring radionuclides: a PIXE approach

This paper reports an assessment of the level of the radionuclides (40)K, (232)Th and (238)U in environmental soil samples (process waste), and hence their calculated dose rates. For this purpose, the radioactivity from three natural radionuclides was determined in tin process-waste samples in Jos, Nigeria. This work is based on the particle induced x-ray emission (PIXE) approach, devoid of the secular equilibrium, and most of the resolution, interference, self-absorption, geometrical and density correction problems inherent in gamma spectrometry. Many potential environmental hazards have been observed and the data would be of use to the government in its remediation plan for the study area. The high hazard indices require taking adequate measures to check exposures, and an underground lining in the waste ponds to prevent direct contact with the waste pile is recommended. The use of the wastes as building materials should be stopped and use of soils around this area in any development projects should be discouraged until detailed studies on indoor radiation doses and the effects on the inhabitants of prolonged exposures have been carried out.

Spatial distribution of gamma radiation levels in surface soils from Jaduguda uranium mineralization zone, Jharkhand, India, using γ-ray spectrometry, and determination of outdoor dose to the population

The concentrations of natural radionuclides in surface soil samples around selected villages of Jaduguda were investigated and compared with the radioactivity level in the region. Concentrations of ²³⁸U, ²³²Th, and ⁴⁰K were determined by a gamma ray spectrometer using the HPGe detector with 50% relative efficiency, and the radiation dose to the local population was estimated. The average estimated activity concentrations of ²³⁸U, ²³²Th, and ⁴⁰K in the surface soil were 53.8, 44.2 and 464.2 Bq kg⁻¹ respectively. The average absorbed dose rate in the study area was estimated to be 72.5 nGy h-1, where as the annual effective dose to the population was 0.09 mSv y-1. A correlation analysis was made between measured dose rate and individual radionuclides, in order to delineate the contribution of the respective nuclides towards dose rate. The radio-elemental concentrations of uranium, thorium and potassium estimated for the soils, in the study area, indicated the enrichment of uranium series nuclide. The results of the present study were subsequently compared with international and national recommended values.

A complimentary tool in the determination of activity concentrations of naturally occurring radionuclides

The determination of activity concentrations of radionuclides requires a reliable gamma spectrometry system, which also depends on the compulsory attainment of secular equilibrium amongst the progenies of the radionuclide of interest. This is often difficult to attain and hence a helium particle induced x-ray emission technique, not requiring the compulsory attainment of secular equilibrium, was used to determine the actual concentrations of the elemental content of tailings from the high background radiation tin mining area, Jos, Nigeria. The activity concentrations of the radionuclides of (40)K, (232)Th and (238)U were also calculated based on their elemental analyses, providing reliable information about the heads of uranium ((238)U) and thorium ((232)Th) series on the study area.

A comparative study of thorium activity in NORM and high background radiation area

Several industrial processes are known to enrich naturally occurring radioactive materials (NORM). To assess such processes with respect to their radiological relevance, characteristic parameters describing this enrichment will lead to interesting information useful to UNSCEAR. In case of mineral treatment plants, the high temperatures used in smelting and refining processes lead to high concentrations of (238)U and (232)Th. Also due to thermal power combustion, concentration of U and Th in the fly ash increases manifold. NORM samples were collected from a Thailand mineral treatment plant and Philippine coal-fired thermal power plants for investigation. Some studies are initiated from a high background radiation area near Gopalpur of Orissa state in India. These NORM samples were analysed by gamma-ray spectrometry as well as inductively coupled plasma mass spectrometry. The radioactivity in case of Orissa soil samples is found to be mainly contributed from thorium. This study attempts to evaluate levels of thorium activity in NORM samples.

Preliminary indoor thoron measurements in high radiation background area of southeastern coastal Orissa, India

This paper presents the preliminary results of radon and thoron measurements in the houses of Chhatrapur area of southeastern coast of Orissa, India. This area is one of the high radiation background radiation areas in India, which consists of monazite sand as the source of thoron. Both active and passive methods were employed for the measurements. Radon and thoron concentrations were measured in the houses of Chhatrapur area using twin cup radon dosemeters, RAD7 and radon-thoron discriminative detector (Raduet). Thoron progeny concentration was also measured in the houses using deposition rate measurements. Radon and thoron concentrations in the houses of study area were found to vary from 8 to 47 Bq m(-3) and the below detection level to 77 Bq m(-3), respectively. While thoron progeny concentration in these houses ranges between 0.17 and 4.24 Bq m(-3), preliminary investigation shows that the thoron concentration is higher than radon concentration in the houses of the study area. The thoron progeny concentration was found to be comparatively higher, which forms a base for further study in the area. The comparison between the results of various techniques is presented in this paper.

Natural radioactivities in iron and nickel ores imported into Japan and the dose assessment for workers handling them

Japan imports Fe and Ni ores from abroad for use as industrial raw materials in the manufacture of industrial products like stainless steel. Some of these ores might contain high levels of radioactivity, and then workers handling them would be exposed to radiation without being aware of it. Activity concentrations in these ores should be measured to evaluate the radiation exposure of workers. In this study, Fe and Ni ores used as industrial raw materials were collected from iron and steel companies, and the activity concentrations of the (238)U series, the (232)Th series and (40)K in these ores were determined using inductively coupled plasma mass spectrometry (ICP-MS) and gamma ray spectrometry. The activity concentrations of the (238)U series, the (232)Th series and (40)K in these ores samples were lower than the International Atomic Energy Agency (IAEA) values. The doses to workers handling these ores were estimated using methods for dose assessment given in a report by the European Commission. In each scenario, a maximum value of the annual effective dose to workers was estimated to be about 6.8 × 10(-6) Sv, which was lower than intervention exemption levels (annual dose 1.0 × 10(-3) Sv) given in International Commission on Radiological Protection (ICRP) Publication 82.

Natural radionuclide content and radiological assessment of clay soils collected from different sites in Ekiti State, southwestern Nigeria

Clay soil samples collected from different sites in Ekiti State, southwestern Nigeria were analysed for their natural radionuclide contents, using the gamma ray spectrometric method. The overall mean activity concentrations of (226)Ra, (232)Th and (40)K obtained in this study were, respectively, 33.6 +/- 5.3, 20.1 +/- 3.3 and 207.2 +/- 113.0 Bq kg(-1). The radiological hazards incurred from the use of the clay soil as a component of building materials were estimated through various radiation hazard indices. The results indicate that the values obtained fall below the internationally accepted maximum limits and as such, the use of clay as a building material does not pose any significant radiation hazard to individuals in the study area.

Natural background dose measurements in south Cameroon

The natural background doses due to (40)K, (226)Ra and (232)Th have been measured in soil samples collected from various sampling sites in the locality of Lolodorf, Cameroon. For data acquisition and analysis, a high-purity germanium detector and a PC-based MCA were used. The mean activity concentrations of (40)K, (226)Ra and (232)Th were measured to be 2001 +/- 521, 329 +/- 491 and 414 +/- 309 Bq kg(-1), respectively, in rock samples, while in soil samples the activity concentrations were found to be 1482 +/- 280 Bq kg(-1) for (40)K, 134 +/- 64 Bq kg(-1) for (226)Ra and 177 +/- 102 Bq kg(-1) for (232)Th. The average outdoor absorbed dose rates in air, 1 m above the ground surface due to soil samples, were estimated to be 218 +/- 61 and 250 +/- 97 nGy h(-1) in the locations of Ngombas and Bikoue, respectively. The corresponding annual effective dose rates in air were determined to be 0.267 mSv y(-1) in Ngombas and 0.307 mSv y(-1) in Bikoue. The level of radioactivity in the studied area is relatively high.

Measurement of natural radioactive nuclide concentrations in various metal ores used as industrial raw materials in Japan and estimation of dose received by workers handling them

Natural resources such as ores and rocks contain natural radioactive nuclides at various concentrations. If these resources contain high concentrations of natural radioactive nuclides, workers handling them might be exposed to significant levels of radiation. Therefore, it is important to investigate the radioactive activity in these resources. In this study, concentrations of radioactive nuclides in Th, Zr, Ti, Mo, Mn, Al, W, Zn, V, and Cr ores used as industrial raw materials in Japan were investigated. The concentrations of (238)U and (232)Th were determined by inductively coupled plasma mass spectrometry (ICP-MS), while those of (226)Ra, (228)Ra, and (40)K were determined by gamma-ray spectrum. We found the concentrations of (238)U series, (232)Th series, and (40)K in Ti, Mo, Mn, Al, W, Zn, V, and Cr ores to be lower than the critical values defined by regulatory requirements as described in the International Atomic Energy Agency (IAEA) Safety Guide. The doses received by workers handling these materials were estimated by using methods for dose assessment given in a report by the European Commission. In transport, indoor storage, and outdoor storage scenarios, an effective dose due to the use of Th ore was above 4.3 x 10(-2)Sv y(-1), which was higher than that of the other ores. The maximum value of effective doses for other ores was estimated to be about 4.5 x 10(-4)Sv y(-1), which was lower than intervention exemption levels (1.0 x 10(-3)Sv y(-1)) given in International Commission of Radiological Protection (ICRP) Publication 82.

Inter-comparison study of the population dose due to gamma-radiation in the coast of North Sinai between Rafah and Bir El-Abd areas

This study compares the external dose due to the gamma-ray emitting radionuclides in various areas in North Sinai, Egypt. The whole area was divided into 10 regions. The average absorbed dose rates were evaluated for each region. It was found that Zaranik-protected area and Al-Massaid have the highest values of 72.7 and 57.2 nGy h(-1), respectively. The corresponding values of the remaining regions were <23 nGy h(-1). The mean annual effective dose equivalents for the four largest cities Rafah, El-Sheikh Zuwaied, Al-Arish and Bir El-Abd were 20.8, 18.8, 57.4 and 14.0 microSv, respectively. The results are compared with those from different areas in Egypt and in various countries.

Spatial distribution of natural radioactivity levels in topsoil around the high-uranium mineralization zone of Kylleng-Pyndensohiong (Mawthabah) areas, West Khasi Hills District, Meghalaya, India

A study of background radiation and the distribution of radionuclides in the environment of the proposed uranium mining sites of Kylleng-Pyndensohiong (Mawthabah) areas, West Khasi Hills District, Meghalaya, India, has been carried out with the objective of establishing a baseline radiation level of the region. Topsoil samples collected from the region are analysed for radioactivity measurements of primordial radionuclides by gamma-spectrometry technique. Direct dose measurement using a survey meter was also carried out simultaneously. Measurement carried out in the region shows that the activity concentration of 238U and 232Th in soil samples is found to be highest in Kylleng with respective median values of 335.3 Bq kg(-1) and 283.9 Bq kg(-1) followed by Syngkai with activity concentration of 285.3 Bq kg(-1) and 257.4 Bq kg(-1) for 238U and 232Th, respectively. The distribution of 40K concentration in the study area is found to be in the range of 173.1-359.0 Bq kg(-1) which is below the global and Indian average values of 420 Bq kg(-1) and 394 Bq kg(-1), respectively. The contribution of the primordial radionuclides to the total dose of the study area is found to be very high with a range of 136.8-334.5 nGy h(-1) in comparison to the global as well as Indian average values.

Natural radioactivity and external gamma radiation exposure at the coastal Red Sea in Egypt

Radionuclides which present in different beach sands are sources of external exposure that contribute to the total radiation exposure of human. In this work, superficial samples of beach sand were collected from the Red Sea coastline (Ras Gharib, Hurghada, Safaga, Qusier and Marsa Alam areas) and at 20 km on Qena-Safaga road. The distribution of natural radionuclides in sand beach samples was studied by gamma spectrometry. The activity concentrations of primordial and artificial radionuclides in samples that are collected from the coastal environment of the Red Sea were 19.2 +/- 3 Bq kg(-1) for (210)Pb, 21.1 +/- 1 Bq kg(-1) for (226)Ra, 22.7 +/- 2 Bq kg(-1) for (238)U, 1.0 +/- 0.1 Bq kg(-1) for (235)U, 11.6 +/- 1 Bq kg(-1) for (228)Ra, 13.0 +/- 1 Bq kg(-1) for (228)Th, 12.4 +/- 1 Bq kg(-1) for (232)Th, 930 +/- 32 Bq kg(-1) for (40)K and 1.2 +/- 0.3 Bq kg(-1) for (137)Cs. The mean external gamma-dose rate was 62.5 +/- 3.2 nSv h(-1), 54.4 +/- 2.8 nGy h(-1) Ra equivalent activity (Ra(eq)) was 107 +/- 5.8 Bq kg(-1), 0.86 +/- 0.04 Bq kg(-1) for representative level index (I(gamma)) and effective dose rate was 0.067 +/- 0.003 mSv y(-1) in beach sand red sea, in air due to naturally occurring radionuclides.

Adaptive response of blood lymphocytes of inhabitants residing in high background radiation areas of ramsar- micronuclei, apoptosis and comet assays

The hot springs in certain areas of Ramsar contain (226)Ra and (222)Rn. The effects of natural radiation on the inhabitants of these areas and the inhabitant's radiosensitivity or adaptive responses were studied. One group of volunteers from areas with high natural background radiation and another group from areas with normal background radiation were chosen as the case and control group respectively. The frequency of micronuclei, apoptosis, and DNA damage in peripheral blood mononuclear cells were measured following gamma irradiation (4 Gy). The incidence of micronuclei in the case group was significantly lower than that in the control group while their frequency of apoptosis was higher (P < 0.05). However, the rates of induced DNA damage and repair were significantly higher in the case group (P < 0.05). Smaller number of micronuclei and higher levels of apoptosis in the case group could be the result of higher resistance to radiation stress and a more rigorous checkpoint at cell division. However, regarding the alkaline labile sites, the individuals in the case group are more sensitive and susceptible to DNA damage. The results of micronuclei, apoptosis and repair studies suggest that an adaptive response might be induced in people residing in areas with high background radiation.

High background radiation areas of Ramsar in Iran: evaluation of DNA damage by alkaline single cell gel electrophoresis (SCGE)

The hot springs in special areas in Ramsar, a northern coastal town in Iran, contain (226)Ra and (222)Rn. The natural radiation effects, radiosensitivity or adaptive responses, on the inhabitants of high natural radiation in Ramsar were studied. The single cell gel electrophoresis was used to monitor DNA damages. Three groups of volunteers were selected, one from high natural background radiation areas as the case group and two from normal background radiation areas as controls (control 1 and control 2). The latter one had the similar living situation to case group while the other (control 2) had different living situation from the other groups. Peripheral blood mononuclear cells (PMNCs) were separated and irradiated by (60)Co source at five different gamma doses. It was found that the spontaneous level of DNA damage and the induced DNA damage in all challenging doses in case group was considerably higher than control groups (p < 0.05). On the other hand, the repair rate in those volunteers, who received less than 10.2 mSv/y was significantly more than the control groups. In the contrary, individuals who live in homes with more than 10.2 mSv/y had incomplete repair. Additionally the plasma and urinary levels of vitamin C were measured spectrophotometrically. Although the concentration of vitamin C of plasma was equal in case and control 1 groups, the urinary level of vitamin C was found to be lower in the case group.

Study of radionuclide distribution around Kudankulam nuclear power plant site (Agastheeswaram taluk of Kanyakumari district, India)

The activity concentration of primordial radionuclides 238U, 232Th and 40K have been measured in the sand samples of Agastheeswaram taluk of Kanyakumari district using gamma-ray spectrometer. The average activity of 232Th, 238U and 40K are found to be 5787.1, 1082.9 Bq kg(-1) and BDL, respectively. The total average absorbed dose rate owing to the presence of 232Th, 238U and 40K is found to be 3900.4 nGy h(-1). The annual effective dose is 4.7 mSv y(-1) and the results are discussed in this paper.

Characteristics, spatial distribution and vertical profile of gamma-ray emitting radionuclides in the coastal environment of North Sinai

Radionuclide concentrations of beach and dune sand from various sites in Al-Arish city and surrounding area, North Sinai, Egypt, were measured. The sampling sites included locations in the local harbor, Al-Arish valley and Zaranik protected area. The results indicate that the activities of the products of (232)Th and (226)Ra series in samples from the harbor and along the beach were higher than those from non-coastal sites. The activity concentrations of (232)Th for beach sand ranged from 2.3 to 506.5 Bq/kg with an average of 83.4 Bq/kg, while that for dune sand ranged from 2.2 to 15.1 Bq/kg with an average of 6.4 Bq/kg. The average activity concentration of (226)Ra for beach sand was 56.0 Bq/kg (2.9-261.5 Bq/kg), while that for dune sand was 6.5 Bq/kg (3.0-14.7 Bq/kg). The average activity concentrations of (40)K for beach and dune sand were 88.1 Bq/kg and 178.4 Bq/kg, respectively. Six depth profiles in the harbor area were measured up to a depth of 1m within more than two years. These sets of measurements allowed the determination of the migration rate of black sand to be 0.094 cm/day. Samples with the smallest grain size (<0.2 mm) were found to have the highest level of activities, which were attributed to their high content of black sand. No risk exists for public health based on the calculated effective dose equivalent and the recommended limit of 5 mSv/y. On the other hand, local children and adults may receive doses higher than this recommended limit in two locations in the Zaranik protected area according to a model developed in this study.