Human health risk assessment of environmental and dietary exposure to natural radionuclides in the Catalan stretch of the Ebro River, Spain

A review of the occurrence of naturally occurring radioactive materials and radiological risk assessment in South African soils

According to reports, exposure to high concentrations of naturally occurring radioactive substances like Uranium-238, Thorium-232, and Potassium-40 poses serious health concerns. This review study aims to report the concentrations of radionuclides in various South African soil and their equivalent risk assessments, which have been sparingly reported. For South Africa, most radionuclide concentrations above the permissible limits of 33, 45, and 420 Bq.kg-1 for 238U, 232Th, and 40K, respectively, have been found in some soil samples taken near industrialization activities, including mining and oil exploration and production. Thus, the amount of radionuclides is a good indicator of the kind of soil, the local geology, and the mineral make-up of the parent rocks. The increases in radiation exposure to people and the environment have been reported to cause various radiological health hazards. Thus, this review study can be used as a data source to track probable radioactive contamination from soils found in South Africa.

Natural radioactivity levels in some vegetable crops under greenhouse conditions

Estimating any radioactivity released into the environment is critical for public health protection, particularly if the radioactivity can enter the food chain. In the present work, the activity concentration of natural radionuclides in the soil, water, plants, and fruits of four vegetable crops, namely cucumber, sweet pepper, hot pepper, and tomato, growing under greenhouse conditions has been measured using a High Purity Germanium (HPGe) Detector. The measured activity concentrations for ²²⁶Ra, ²³²Th, and ⁴⁰K in the studied soil samples ranged from 4.7 to 6.8, 3.4 to 6.1, and 63.9 to 112.4 Bq kg^-1, respectively, while in plants, they ranged from Not Detected (ND) to 15.2, ND to 3.4, and 495.1 to 1467.4 Bq kg^-1, respectively. The measured activity concentrations for ⁴⁰K in the studied fruit samples ranged from 967.1 to 1459.1 Bq kg^-1, while ²²⁶Ra and ²³²Th were not detected. The Transfer Factor (TF) of ²²⁶Ra, ²³²Th, and ⁴⁰K from soil to plants and fruits has been evaluated, and the results from soil to plants varied from ND to 2.5, ND to 0.8, and 6.0 to 19.2, while the results for ⁴⁰K in fruits varied from 8.7 to 18.4, while ²²⁶Ra and ²³²Th were not detected.

The Concentration of Radionuclides (Lead-210, Polonium-210, and Cesium-137) in the Muscle of Sardine Fish: a Global Systematic Review, Meta-analysis, and Exposure Assessment

With the increasing use of nuclear technology, concerns about the contamination of water resources with radionuclides and the contamination of seafood are increasing. In the current investigation, a meta-analysis and exposure assessment regarding the concentration of radionuclides, including lead-210 (Pb-210), polonium -210 (Po-210), and cesium-137 (Cs-137) in the muscle of Sardin fish were conducted. In this regard, some databases including Scopus and PubMed were selected to retrieve papers on the concentration of radionuclides in the muscle of Sardin fish from January 2000 to 25 June 2021. The used keywords were polonium-210, natural radioactivity, lead-210, radiocesium, cesium-137, radionuclides, radium-226, seafood, marine foods, fish, sardine fish, sardinella longiceps, and Clupeidae. Also, effective dose (ED) was calculated to estimate carcinogenic risk in Sardine fish consumers. The rank order of radionuclides in the muscle of sardine fish was Po-210 (31.50 Bq/kg) > Pb-210 (3.34 Bq/kg) > Cs-137 (0.48 Bq/kg). Based on level of Pb-210 rank of countries was France (12.00 Bq/kg) > India (4.06 Bq/kg) > Turkey (3.29 Bq/kg) > Spain (1.00 Bq/kg) > Slovenia (0.55 Bq/kg); Po-210 was Turkey (74.96 Bq/kg) > Spain (48.00 Bq/kg) > France (31.500 Bq/kg > India (30.25 Bq/kg) > Slovenia (25.00 Bq/kg) > Kuwait (7.28 Bq/kg) and also, Cs-137 was Japan (1.22 Bq/kg) > Croatia (0.18 Bq/kg) > India (0.23 Bq/kg). The lowest and highest ED of ²¹⁰Po was observed in Kuwait (5.10E-04 msv/y, female) and France (3.14E-01, male); Pb-210, Slovenia (7.24E-05 msv/y, male) and France (1.48E-02 msv/y, female), and Cs-137, Croatia (8.47E-08 msv/y, male) and Japan (2.54E-05 msv/y, female), respectively. The risk assessment shows that the exposed population are at an acceptable range of risk (H < 1 mSv/y).

Impact assessment of a large river on the sediments and fish from its continental shelf: using Solea solea as sentinel in the Ebro river mouth (NW Mediterranean, Spain)

Many studies have been carried out along mighty rivers with heavily industrialized watersheds to evaluate pollutants and their effects on freshwater organisms. However, their impact on marine organisms is virtually unknown. In order to cover this gap, Solea solea, one of the most important commercial fish species, together with sediments, were sampled during 2013-2015 offshore from the Ebro Delta river mouth. Fish health indicators (condition indices, histological tissue alterations, and parasite descriptors) were used to assess the potential effect of pollutants, an issue of particular interest in the area following the dredging activities taking place in the river upstream in 2013. No major histopathological alterations were detected, but perivascular inflammatory foci (PIF) were frequently observed, especially in 2014. The most prevalent and abundant parasites were acanthocephalans and digeneans within the digestive tract and copepods on the gills. Levels of trace metals from sediments and fish muscle were below the effects range median and reference levels accepted for human consumption, respectively. However, the lower levels of the hepatosomatic index, higher numbers of PIF, and variations in the abundance of parasites in 2014 and 2015 could suggest a pollutant exposure during these years. These results warn signs of toxicity, which could be associated with sediment leaks during the dredging activities.

The distribution, contamination and risk assessment of heavy metals in sediment and shellfish from the Red Sea coast, Egypt

Zn, Cu, Ni, V, Al, Pb, Cd, Hg, lipid and water contents were determined in the soft tissues of different shellfish species collected along the Red Sea shoreline. Metal contents showed a descending order of Zn > Cu > Ni > Al > V > Pb > Cd > Hg. The leachable concentrations found in the sediments gathered from the studied locations gave another descending order: Al > Zn > Ni > Pb > V > Cu > Cd. The determined leachable heavy metal contents in the sediment did not exceed the NOAA and CCME (Anonymous 1999) sediment quality guidelines. Accordingly, the sediments along the Egyptian Red Sea area did not pose any adverse impacts on the biological life. According to the hazard quotient (HQ) calculations for heavy metal contents in the soft tissue of shellfish, mercury did not pose any risk on human health; whereas, the other determined heavy metals gave HQ values of 1 < HQ < 10 and showed a possibility of risk on the long term. Cu is above the desirable levels in mussels. The RQ calculations of toddlers and adults reflected that Cu was the only heavy metal that had an adverse effect on toddlers' health. Based on the human organizations (EPA, BOE, MAFF, and NHMRC) that proposed safety concentrations of heavy metals, the studied shellfish were somewhat safe for human consumption.

Assessment of radiological risk for marine biota and human consumers of seafood in the coast of Qingdao, China

This paper reports the levels of (226)Ra, (232)Th, (40)K and (137)Cs in the edible parts of 11 different marine species collected from the Qingdao coast of China. The activities of (226)Ra, (232)Th and (40)K ranged from 0.08±0.03 to 1.65±0.60 Bq kg(-1) w.w., 0.09±0.02 to 1.44±0.10 Bq kg(-1) w.w., 26.89±1.25 to 219.25±5.61 Bq kg(-1) w.w., respectively. Artificial (137)Cs was undetectable or close to the detection limit in the biota sampled. To link radioactivity to possible impact on health, we calculated radiation doses to both the marine biota and human beings. We showed that doses in all cases were dominated by naturally occurring (40)K and that (137)Cs doses were negligible compared with (40)K-derived doses. The total doses to marine biota ranged between 16.55 and 62.41 nGy h(-1) among different biota species, which were below the benchmark level of aquatic organism. The committed effective dose to humans through seafood consumption varied from 10.55 to 36.17 μSv y(-1), and the associated lifetime cancer risks ranged from 5.93E-05 to 9.49E-05 for different age and gender groups. Both the dose and cancer risk to humans were at the acceptable range. Despite the significant amount of radionuclides released as a result of the Fukushima accident, their impact on the seafood in Qingdao coast appears to be negligible based on our measurements of concentrations of radionuclide activity and internal dose estimates.

Environmental concentrations of metals in the catalan stretch of the ebro river, Spain: assessment of temporal trends

The aim of this study was to investigate the environmental impact and the human health risks associated with exposure to a number of metals before and after initiating the decontamination process in Flix dam (Catalonia, Spain). The concentrations of As, Cd, Cr, Cu, Mn, Hg, Ni, and Pb were determined in samples of drinking water, river water, and soils collected in the Catalan stretch of the Ebro River, Spain. The results were compared with those of previous surveys performed in the same zones. Human exposure to metals, as well as the associated carcinogenic and non-carcinogenic risks, was also estimated. In river and drinking waters, most analyzed metals showed increases, being significant that of Cr. The movements of polluted sludge in Flix dam could be the reason for the Cr levels found in the current survey. However, Hg was not detected in both drinking and river waters. Important differences on Mn levels were found, being higher those in river water than in drinking water. In turn, although soil concentrations of all analyzed metals showed a decreasing temporal trend, the reductions were only significant for Ni. The hazard quotient (HQ) of all elements was below the unity, considered the safe threshold. For carcinogenic risks, all values were found to be lower than 10(-5), which has been defined as the maximum recommended excess of cancer risk according to the Spanish Legislation. The only exception was the As exposure through soil and drinking water, which slightly exceeded this threshold. The current results indicate the need to perform a continuous assessment of metal levels not only in river waters, but also in drinking water in order to assure the harmlessness of the decontamination process for the health of the population living downriver (Ebro) the Flix dam.

Distribution of Po-210 in two species of predatory marine fish from the Brazilian coast

Polonium-210 ((210)Po) concentration was quantified in the muscle tissue and organs of two predatory marine fishes (Genypterus brasiliensis and Cynoscion microlepidotus) from Cabo Frio, Rio de Janeiro, Brazil. The species C. microlepidotus, a benthic carnivore, registered higher (210)Po in its tissue. The organs associated with digestion displayed the maximum radionuclide compared with other organs. The average activity was 2 mBq kg(-1) for G. brasiliensis and it was 6 mBq kg(-1) for C. microlepidotus. The activity concentrations varied significantly between the species and among organs.

Dynamic interactions between hydrogeological and exposure parameters in daily dose prediction under uncertainty and temporal variability

We study the time dependent interaction between hydrogeological and exposure parameters in daily dose predictions due to exposure of humans to groundwater contamination. Dose predictions are treated stochastically to account for an incomplete hydrogeological and geochemical field characterization, and an incomplete knowledge of the physiological response. We used a nested Monte Carlo framework to account for uncertainty and variability arising from both hydrogeological and exposure variables. Our interest is in the temporal dynamics of the total dose and their effects on parametric uncertainty reduction. We illustrate the approach to a HCH (lindane) pollution problem at the Ebro River, Spain. The temporal distribution of lindane in the river water can have a strong impact in the evaluation of risk. The total dose displays a non-linear effect on different population cohorts, indicating the need to account for population variability. We then expand the concept of Comparative Information Yield Curves developed earlier (see de Barros et al. [29]) to evaluate parametric uncertainty reduction under temporally variable exposure dose. Results show that the importance of parametric uncertainty reduction varies according to the temporal dynamics of the lindane plume. The approach could be used for any chemical to aid decision makers to better allocate resources towards reducing uncertainty.

Radiological of natural and mineral drinking waters in Slovenia

Various types of water were collected in Slovenia and analysed in order to assess the radiation doses from (238)U, (234)U, (228)Ra, (226)Ra, (210)Pb and (210)Po for three different age groups of the population. It was found in all cases that the calculated median committed effective dose from the investigated radionuclides for each population group was well below the recommended value of 100 µSv y(-1), ranging from 4 to 7 µSv y(-1) for adults, from 8 to 10 µSv y(-1) for children and from 6 to 7 µSv y(-1) for infants. Of the investigated groups of the population children are the most exposed with the highest absolute doses of 19.1 and 18.7 µSv y(-1) after drinking a certain bottled brand of mineral and natural water, respectively. The contribution of each particular radionuclide to total doses varied among different water types and within each type, as well as between different age groups.