High accumulation of Po concentration in muscle tissue and hepatopancreas gland organs of Asian green mussel (Perna viridis) at the coastal area of Binh Thuan, Vietnam: Radiological protection perspectives.

Po (polonium) has high radiotoxicity that tends to accumulate in marine bivalves inhabiting coastal zones with elevated background levels of primordial radionuclides. In this study, the Po concentration in two organs of the Asian green mussel (Perna viridis), collected from the coastal region of Binh Thuan, Vietnam, was determined using alpha spectrometry. The results showed a significant difference in Po activity concentration between the two organs of P. viridis, with markedly higher concentrations observed in the hepatopancreas gland compared to the muscle tissue, approximately six times greater. The mean Po activities were 74.9 ± 7.8 Bq·kg (range: 30.3 ± 16.7 to 111 ± 10.6 Bq·kg) in muscle tissue and 431 ± 7.8 Bq·kg (range: 187 ± 8 to 763 ± 7 Bq·kg) in the hepatopancreas. This marked difference may be attributed to the affinity of Po for certain proteins such as ferritin and metallothionein. The elevated accumulation of Po in two organs may be linked to its filter-feeding behavior, its diet of plankton and organic particles, its biological characteristics, and local environmental conditions (relating to the titanium mining). Insignificant correlations were observed between Po concentrations and shell length, total body mass, or estimated age of the mussels. This suggests that mussels of any size, age, or weight can serve as suitable sampling organisms for environmental biomonitoring programs targeting marine Po contamination. Radiological risk assessment using the ERICA tool indicated negligible ecological impact of Po on marine biota in the study area, except for sample group 15, which exhibited a Risk Quotient (RQ) of 1.00 and a total dose rate of 10 μGy·h, equivalent to the screening reference level. This suggests that Po activity in the body may have a potential impact on this mussel species. Annual committed effective doses from dietary intake of mussels, particularly from the hepatopancreas, exceeded the recommended dose limit of 1 mSv·y in most cases. This study provides essential baseline data for radiological protection and environmental monitoring along the Vietnamese coastline. The findings emphasize the necessity for targeted radiation risk management strategies and reinforce the utility of Asian green mussel as a reliable biomonitor of Po contamination in tropical marine ecosystems.