Atmospheric fallout of ⁷Be in bulk precipitation at the Adriatic coast, Croatia

ABSTRACT

Atmospheric fallout of naturally occurring cosmic radionuclide ⁷Be was monitored in bulk precipitation over a year (July 2018 to June 2019) at a coastal station (Martinska) of the Adriatic Sea, Croatia. The monthly depositional fluxes varied between 25.08 and 78.97 Bq m⁻² month⁻¹ (average: 49.18 ± 19.17 Bq m⁻² month⁻¹) and showed a significant correlation with precipitation (r = 0.92). The highest seasonal flux observed in winter (172 ± 4.31 Bq m⁻² season⁻¹) coincides with the highest amount of precipitation (190 mm), suggesting an important role of precipitation in the scavenging process of ⁷Be deposition to the surface. The monthly volume-weighted activities of ⁷Be varied from 0.63 to 5.74 Bq L⁻¹ (average: 1.96 ± 1.7 Bq L⁻¹) with the highest value corresponding to the summer season. The precipitation-normalised enrichment factor (α) indicates a higher depositional flux of ⁷Be in the summer season than the desired value due to the stratosphere-troposphere exchange and the contribution of dry deposition. The annual bulk depositional flux of ⁷Be was 590 Bq m⁻² y⁻¹, which is comparable with several Mediterranean coastal stations. The annual bulk depositional fluxes of ⁷Be in the 30°N - 50°N latitude band showed a good correlation with precipitation and established that the atmospheric fallout of this radionuclide is mainly governed by precipitation in that given latitude band.

KEYWORDS:

• Atmospheric fallout
• cosmic radionuclide
• ⁷Be
• Adriatic Sea
• bulk precipitation

Acknowledgments

We would like to thank Mr Yuda Chen for his kind help in sampling.

Disclosure statement

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

Author contributions

Milki Debi: Methodology and Writing the original draft. Jinlong Wang: Conceptualization; Review and editing. Qianqian Bi: Methodology. Xu Ren: Methodology. Aftabuddin Sheikh: Review and editing. Neven Cukrov: Field investigation and editing. Jinzhou Du: Conceptualization; Funding Acquisition; Review and editing.

Data availability statement

Data will be made available on request.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/03067319.2024.2304068

Additional information

Funding

This work was funded by the National Key R & D Programme of China [2022YFE0209300].