Assessment of the level and risk of radioactive hazards in coastal sediments in northern Vietnam

ABSTRACT

Radioactivity in coastal sediments in northern Vietnam was examined using data from five sediment cores to assess radioactivity concentrations and radiation risk indices. Radiation risk indices included radium equivalent activity (Ra_eq), the absorbed dose rate (ADR), the annual effective dose equivalent (AEDE), the activity utilization index (AUI), the external hazard index (H_ex), the representative level gamma index (I_γr), and the annual gonadal effective dose rate (AGDE). The radioactivity concentrations of ⁴⁰K, ²³²Th, ²²⁶Ra, ²³⁸U, and ¹³⁷Cs were 567, 56.1, 35.1, 37.9, and 1.18 Bq/kg, respectively. The average concentrations of ⁴⁰K, ²³²Th, ²²⁶Ra, and ²³⁸U were above the global average at five sites, except for ¹³⁷Cs, which was low. The Ra_eq, H_ex, and AUI indices were below the recommended values, while the AEDE, ADR, AGDE, and I_γr indices were above the recommended values. Moreover, ⁴⁰K, ²³²Th, ²²⁶Ra, and ²³⁸U had significant impacts on the radiation hazard indices Ra_eq, ADR, AEDE, I_γr, AUI, H_ex, and AGDE. There are three coastal sediment groups on the northern coast of Vietnam: Group 1 has a higher radioactivity and radiation risk index than Group 2 but a lower value than Group 3. Group 3 had the highest radioactivity and radiation risk index. The values of ⁴⁰K, ²³²Th, ²²⁶Ra, and ²³⁸U and the ADR, AUI, I_γr, and AGDE indices in the sediment threaten the living environment.

KEYWORDS:

• Radioactive
• radiation hazard
• northern Vietnam
• coastal sediments
• natural radioactivity
• Mong Cai‌
• ‌Hai Phong
• Thua Thien Hue

Acknowledgements

The authors would also like to thank Mr. Nguyen Huy Hoang and Mr. Le Anh Xuan for their help to collect samples.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Authors’ contributions

Conception and design: Dang Hoai Nhon, Phan Son Hai, Tran Duc Thanh. The material preparation, data collection, and analyses: Dang Hoai Nhon, Bui Thi Thanh Loan, Nguyen Dac Ve, Bui Van Vuong, Nguyen Thi Mai Luu, Tran Huu Long, Hoang Thi Chien, and Nguyen Duc The. The first draft of the manuscript was revised by Dang Hoai Nhon and Phan Son Hai. All the authors have read and approved the final manuscript.

Declarations

All authors have read, understood, and complied as applicable with the statement on “Ethical responsibilities of Authors”, as found in the Instructions for Authors, and are aware that with minor exceptions, no changes can be made to authorship once the paper is submitted.

Consent to publish

All of the authors agree with the present submission of this paper.

Data availability statement

Raw data will be made available upon request.

Additional information

Funding

This paper is the result of the research projects of the Ministry of Science and Technology (MOST) (ĐTĐLCN.14/23) and the Vietnam Academy of Science and Technology (VAST) (VAST05.03/24-25), which provided financial support for the implementation.