A review of radioactivity in the Gulf region

The region around the Gulf is moving toward a nuclear energy option with the first nuclear power plant now operational in Bushehr, Iran. Others are soon to be commissioned in Abu Dhabi and in Saudi Arabia. For this reason, radiological safety is becoming a prime concern in the region. This review compiles published data on radionuclide concentrations in seawater, sediment, and biota that have been analyzed in the Gulf countries, along with spatial distribution patterns to enable a synoptic view of the available datasets. The seawater concentrations of ³H, ²¹⁰Po, ²¹⁰Pb, ¹³⁷Cs, and ⁹⁰Sr varied between 130 and 146, 0.48-0.68, 0.75-0.89, 1.25-1.38, 0.57-0.78 mBq L^-1, respectively. The ²²⁶Ra concentration in seawater varied between 0.26 and 3.82 Bq L^-1. Extremely high ⁴⁰K concentrations between 132 and 149 Bq L^-1 have been reported from the Iranian coast compared to 8.9-9.3 Bq L^-1 from the western side of the Gulf. Concentrations of ⁴⁰K, total ²¹⁰Pb, ¹³⁷Cs, ⁹⁰Sr, ²²⁶Ra, ²²⁸Ra, ²³⁸U, ²³⁵U, ²³⁴U, ^239+240Pu, and ²³⁸Pu were determined in sediment and ranged between 353 and 445, 23.6-44.3, 1.0-3.1, 4.8-5.29, 17.3-20.5, 15-16.4, 28.7-31.4, 1.26-1.30, 29.7-30.0, 0.045-0.21 and 0.028-0.03 Bq kg^-1 dry weight, respectively. Significantly higher ¹³⁷Cs values have been reported from the Iranian coast compared to the western coast of the Gulf. Whole fish concentrations of ⁴⁰K, ²²⁶Ra, ²²⁴Ra, ²²⁸Ra, ¹³⁷Cs, ²¹⁰Po and ⁹⁰Sr ranged between 230 and 447, 0.7-7.3, <0.5-6.6, <0.5-15.80, <0.17, 0.88-4.26 and 1.86-5.34 Bq kg^-1 dry weight, respectively. ²¹⁰Po was found to be highly concentrated in several marine organisms with the highest ²¹⁰Po concentration found in the clam Marcia marmorata (193.5-215.6 Bq kg^-1 dry weight). The review highlights the overall paucity of data and inconsistencies in the measurement of radionuclides throughout the Gulf region. Further, since the region is moving toward nuclear energy to meet its increasing energy demand, and coupled with the environmental effects from offshore oil exploration and the heavy impact of climate change, there is a pressing need to undertake a comprehensive marine radioactivity monitoring and assessment effort by conducting a joint cruise in the Gulf with participation of all the adjoining countries. Several recommendations on sampling marine matrixes in the Gulf are given with the aim of improving comparability of radionuclide data from the various studies undertaken in the Gulf region.

210Po concentration in selected diatoms and dinoflagellates in the northern Arabian Gulf

Marine phytoplankton is a primary producer in the ocean that forms the base of the marine food web and supports the pelagic food chain. The two dominant groups of phytoplankton observed in northern Gulf waters are diatoms and dinoflagellates. The diatoms outnumber dinoflagellates in the Gulf waters. This study presents baseline information on the concentration of ²¹⁰Po among selected phytoplankton in the northern Gulf. The concentration among diatoms varies between 6.99 and 11.4 Bq kg^-1 wwt, whereas a higher concentration range of 8.51-15.41 Bq kg^-1 wwt was observed among dinoflagellates. The diatoms analyzed includes Thalassiosira spp. - 10.2-11.4 Bq kg^-1 wwt; Chaetoceros spp. - 6.99-7.14 Bq kg^-1 wwt; Rhizosolenia spp. - 9.12-9.95 Bq kg^-1 wwt. The analyzed dinoflagellate genera include Gymnodinium spp. - 8.51-8.78 Bq kg^-1 wwt; Noctiluca spp. - 15.2-15.4 Bq kg^-1 wwt; and Karenia spp. - 14.1-14.9 Bq kg^-1 wwt. The ²¹⁰Po concentration in seawater shows a seasonal variation, with a higher concentration range of 0.70 and 0.58 mBq L^-1 during summer and autumn, whereas a lower range in concentration of 0.38 and 0.30 mBq L^-1 occurring during winter and spring. The resultant computed concentration factors vary between 2 ∗ 10⁴-5 ∗ 10⁴ demonstrating a significant ²¹⁰Po enrichment in the base of the pelagic food chain.

Plutonium and cesium baseline concentrations in seawater from northern Arabian Gulf

The Arabian Gulf is a semi-enclosed water body that has witnessed accelerated anthropogenic activity, in terms of commissioning of nuclear power plants, desalination facilities, oil refineries and extensive coastal development. Furthermore, three wars during the past three decades is a potential worry. This study presents the first plutonium baseline in seawater from the Northern Arabian Gulf. The ^239+240Pu concentrations in seawater vary, between 2.9 and 4.9mBqm^-3, a range that is comparable to other water masses at this latitude. The ²³⁸Pu ranged between 0.04 and 0.05mBqm^-3 and the ¹³⁷Cs concentration between 1.04 and 1.18Bqm^-3. The ratio of ²³⁸Pu/^239+240Pu at all eight sampling stations was 0.01, while the ratio of ^239+240Pu/¹³⁷Cs varied between 0.01 and 0.02. The presence of ¹³⁷Cs and ^239+240Pu in seawater from this region can mainly be attributed to the global atmospheric deposition and fluvial transport. The seawater concentration of ^239+240Pu is five order of magnitude lower than bottom sediments in the area.

Phthalates in indoor dust in Kuwait: implications for non-dietary human exposure

Phthalates are semivolatile organic compounds with a ubiquitous environmental distribution. Their presence in indoor environments is linked to their use in a variety of consumer products such as children's toys, cosmetics, food packaging, flexible PVC flooring among others. The goal of this study was to investigate the occurrence and concentration of phthalates in dust from homes in Kuwait and to assess non-dietary human exposure to these phthalates. Dust samples were randomly collected from 21 homes and analyzed for eight phthalates. The concentrations of total phthalates were log normally distributed and ranged from 470 to 7800 μg/g. Five phthalates [Di(2-ethylhexyl) phthalate (DEHP), Di-n-octyl phthalate (DnOP), Di-n-butyl phthalate (DBP), Benzyl butyl phthalate (BzBP), and Dicyclohexyl phthalate (DcHP)] were routinely detected. The major phthalate compound was DEHP at a geometric mean concentration of 1704 μg/g (median, 2256 μg/g) accounting for 92% of the total phthalates measured. Using the measured concentrations and estimates of dust ingestion rates for children and adults, estimated human non-dietary exposure based on median phthalate concentrations ranged from 938 ng/kg-bd/day for adults to 13362 ng/kg-bd/day for toddlers. The difference in exposure estimates between children and adults in this study supports previous reports that children are at greater risk from pollutants that accumulate indoors.

Baseline concentration of 210Po in Kuwait's commercial fish species

This baseline study highlights the (210)Po variation in whole fishes with different feeding habits. Whole-body (210)Po concentrations were determined in ten important commercial fish species found in the northern Arabian Gulf to serve as baseline data. Primarily, (210)Po is absorbed from water, concentrated by phytoplankton and microzooplankton, and then transferred to the next trophic level along the marine food chain. The lowest concentration of (210)Po was measured in larger carnivorous fishes like hamoor (0.089 Bq kg(-1)), while the highest was found in the fishes that feed on algae, zooplanktons and detritus, like battan (3.30 Bq kg(-1)). The baseline data can be used to understand both the trophic transfer of (210)Po in the marine food chain and the (210)Po concentration factors in fish from the Arabian Gulf.

Bottom sediments of the Arabian Gulf--II. TPH and TOC contents as indicators of oil pollution and implications for the effect and fate of the Kuwait oil slick

Measurements of total petroleum hydrocarbon (TPH) concentrations in 77 core samples collected in 1992 from the bottom sediments of the Arabian Gulf were used to delineate oil pollution levels and their distribution in the region. Seven chronic moderately (TPH 50-89 microg g(-1)) and heavily (TPH 266-1448 microg g(-1)) polluted areas were identified; three in the northern part of the region and four in the southern part. Oil pollution in these areas was attributed to natural oil seepage, accidental damage to pipelines, accidental spillage from tankers, the Nowruz oil slick, and tanker deballasting. Present-day intermediate (TPH 50-114 microg g(-1)) and high (TPH 200-1122 microg g(-1)) pollution levels were identified in 10 areas. Of these, three polluted areas in the northeastern corner, offshore Saudi Arabia and offshore Bahrain, Qatar and United Arab Emirates are probably directly affected by the Kuwait oil slick. A new scenario is suggested for the movement and fate of the oil slick, in which additional large oil discharges from northern sources, as well as substantial quantities of eroded oiled sediments and oil floating from heavily impacted tidal flats along the Saudi Arabian coastline, serve as sources of oil pollution. A definite relationship exists between the grain-size distribution and the TPH content of bottom sediments, with the highest TPH concentrations in the muddy sediments, suggesting that adsorption onto muds is the primary mechanism of oil pollutant accumulation in the Arabian Gulf. Total organic carbon measurements do not correlate positively with the grain-size distribution and TPH contents of the sediments, and hence cannot be used as indicators for petroleum hydrocarbon pollution in the Arabian Gulf.

Bottom sediments of the Arabian Gulf--III. Trace metal contents as indicators of pollution and implications for the effect and fate of the Kuwait oil slick

The trace metal contents of 71 core samples collected in 1992 from the bottom sediments of the Arabian Gulf are used to determine the regional distribution of concentration and pollution levels of these substances in the region. Chronic contamination was recorded in seven locations: the northwestern area (Fe), the northeastern area (Fe, V and Ni), the north-central area (V and Ni), the central area (Fe, Pb, V and Ni), the south-central area (Cu), the eastern area (Cu) and the southeastern area (Fe, V and Ni). Present-day contamination was identified in three locations only: the north-central area (V), the central area (Pb, V and Ni) and the southeastern area (Fe, V and Ni). Diversified natural and anthropogenic inputs may have provided the sources of this contamination. The V/Ni ratios of recent marine sediments cannot be used in identifying oil spillages or in oil-sediment correlation studies. Positive correlations are found between increasing trace metal concentration and decreasing carbonate content and grain size, verifying that adsorption onto muds is the primary mechanism of trace metal concentration in marine sediments. Correlations with TOC (total organic carbon) contents indicate that organic matter is a significant concentrator only in the case of Pb and Cu. With the exception of the Fe contamination in the northwest area due to river transport, all chronic and present-day trace metal concentrations are within the permissible natural background levels in the western offshore areas, including the two areas thought to be polluted by the Kuwait oil slick, thereby supporting the idea that airborne fallout from oil fires was deposited in a limited coastal area between Kuwait and Bahrain, and verifying that the oil slick had minimal effect on the state of pollution by trace metals in the Arabian Gulf.