IMPACT OF THE THREE GORGES WATER CONSERVANCY PROJECT ON RADIOACTIVITY CONCENTRATION LEVELS IN SURROUNDING WATERS

The impact of depleted uranium on the environment in Serbia

During the 1999 war, NATO forces used >30,000 rounds of depleted uranium (DU) ammunition, with a total mass of around 10 tons, on the then Federal Republic of Yugoslavia (now the Republic of Serbia). After the war, between 2002 and 2007, land decontamination was carried out. This paper presents a comprehensive study of the impact of depleted uranium on soil and water in Serbia, with a special focus on contaminated locations in southern Serbia. The study includes key results from analyses of uranium isotopes 238U and 235U in soil and water, and their ratio (235U/238U) before and after land decontamination. Data from the UNEP international mission, as well as other studies from the end of the war to the present, were analyzed. Reported values of 238U and 235U in the remaining penetrators were 12.7 ∙ 106 Bq/kg and 1.9 ∙ 105 Bq/kg, respectively. The maximum measured values of 238U in contaminated soil were up to 307,000 Bq/kg, and 235U values were up to 3920 Bq/kg. The established 235U/238U ratios indicate that the contamination of soil with DU was near the impact sites of the penetrators, while values in more distant samples were within natural levels. It was found that the water in southern Serbia was not contaminated with DU and that the concentrations were comparable to other studies. After the remediation measures were carried out on contaminated sites, no DU presence was detected in soil or water. This is confirmed by DU monitoring results in Serbia conducted from 2013 to 2023. Additional studies for other parts of Serbia show no evidence of environmental contamination with DU, as all results are comparable to reported global values. Furthermore, to minimize any potential health risks to people, continuous monitoring of uranium at high-risk locations in southern Serbia is necessary.

A review of 210Pb and 210Po in moss

Among environment contaminants, 210Pb and 210Po have gained significant research attention due to their radioactive toxicity. Moss, with its exceptional adsorption capability for these radionuclides, serves as an indicator for environmental 210Pb and 210Po pollution. The paper reviews a total of 138 articles, summarizing the common methods and analytical results of 210Pb and 210Po research in moss. It elucidates the accumulation characteristics of 210Pb and 210Po in moss, discusses current research challenges, potential solutions, and future prospects in this field. Existing literature indicates limitations in common measurement techniques for 210Pb and 210Po in moss, characterized by high detection limits or lengthy sample processing. The concentration of 210Pb and 210Po within moss display substantial variations across different regions worldwide, ranging from Collapse

Key Words

• (210)Pb
• (210)Po
• Environmental contamination
• Measurement method
• Moss bioindication

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MESH Headings

• Lead Radioisotopes/analysis
• Polonium/analysis
• Bryophyta/chemistry
• Radiation Monitoring/methods

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Affiliation(s)

Chenlu Ding College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu, 610059, Sichuan, PR China
Qiang Yang College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu, 610059, Sichuan, PR China; Sichuan Cancer Hospital & Institute, Affiliated Cancer Hospital of University of Electronic Science and Technology of China, Chengdu, 611731, PR China.
Xue Zhao Chongqing Radiation Environment Supervision and Management Station, Chongqing, 400015, PR China
Lipeng Xu Sichuan Cancer Hospital & Institute, Affiliated Cancer Hospital of University of Electronic Science and Technology of China, Chengdu, 611731, PR China
Hui Tang College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu, 610059, Sichuan, PR China; Sichuan Management and Monitoring Center Station of Radioactive Environment, Chengdu, 611139, PR China
Zhengshang Liu College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu, 610059, Sichuan, PR China
Juan Zhai College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu, 610059, Sichuan, PR China
Qingxian Zhang College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu, 610059, Sichuan, PR China

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Levels, sources, variations, and human health risk assessment of 90Sr and 137Cs in water and food around Sanmen Nuclear Power Plant (China) from 2011 to 2020

Objectives

Radioactivity monitoring around nuclear facilities is crucial to provide important baseline data for effective detection of radioactive leakage to the environment. We aim to establish a baseline study for monitoring radioactive levels of ⁹⁰Sr and ¹³⁷Cs around Sammen Nuclear Power Plant (SNPP) and to assess their associated health impact on surrounding residents.

Methods

In this study, we collected water and food samples around the SNPP from 2011 to 2020 and determined for ⁹⁰Sr and ¹³⁷Cs activity concentrations. We statistically analyzed the temporal trends of ⁹⁰Sr and ¹³⁷Cs and evaluated their radiation exposure to the local residents.

Results

During this period, the activity concentrations of ⁹⁰Sr and ¹³⁷Cs varied within 1.2-9.9 mBq/L and 0.10-7.6 mBq/L in water, and 0.037-1.3 Bq/kg and 0.011-0.45 Bq/kg in food, respectively, with no significant seasonal variation trend.

Conclusions

All reported activity concentrations of ⁹⁰Sr and ¹³⁷Cs were significantly lower than the recommended value of WHO and Chinese national standards. There is no indication of notable radioactive release into the study area due to the operation of SNPP during 2018-2020. The annual effective doses (AEDs) from the ingestion of ⁹⁰Sr and ¹³⁷Cs in water and food were well below the international permissible limits, indicating the radiation exposure around SNPP during 2011-2020 was kept at a safe level.

Application of grading evaluation method of water radioactivity level in Chongqing section of Yangtze River

The major rivers in a region are usually vital sources of drinking water for local populations, and the concentration of radionuclides in the water is intimately tied to people's health. The varying concentration limits set by the World Health Organization are appropriate as screening values for determining the pollution of water sources, but their capacities as regulatory or early warning limits are restricted. In daily management, the regulatory authority needs to manage water bodies by level based on the concentration of radionuclide to indicate the potential pollution risks. From 2017 to 2019, a statistical analysis and dosage evaluation were conducted on the water radioactivity level in the Chongqing section of the Yangtze River in this study. The Modified Nemerow Index method based on the dose conversion coefficients was applied for the grading evaluation of the water radioactivity level, allowing the grading effect discussed. The results showed that the concentration of radionuclides in the Chongqing section of the Yangtze River and its contribution to the annual effective dose of the human body were lower than the limits stated in the Guidelines for Drinking Water Quality (Fourth Edition). And the samples in the section were 52.94% in Grade Ⅰand 47.06% in Grade Ⅱ, meaning few potential radioactive pollution risks exist there. Compared with other methods. The Modified Nemerow Index method combines the Traditional Nemerow Index method with the dose conversion coefficient of nuclides making it more realistic for the early warning and control of radioactive pollution in water bodies, which is worth popularizing and implementing.