Nguyen Huu Quyet, Le Hong Khiem, Trinh Thi Thu My, Nguyen Thi Bao My, Marina Frontasieva, Inga Zinicovscaia, Nguyen An Son, Tran Thien Thanh, Le Dai Nam, Khuat Thi Hong, Nguyen Ngoc Mai, Trinh Dinh Trung, Duong Van Thang, Nguyen Thi Thuy Hang
Environmental Engineering and Management Journal
Abstract:
Atmospheric deposition of chemical elements in the Hanoi region has been investigated in this study based on moss biomonitoring. Twenty-seven Barbula indica moss samples were collected from the end of 2016 to the beginning of 2017, and the concentrations of 33 chemical elements in the samples were determined by instrumental neutron activation analysis. The results show that Hanoi’s air is highly polluted with Zn, Ba and Ta, and slightly polluted with Al, Cl, Sc, Ti, V, Cr, Mn, Fe, Ni, Co, As, Cd, Sb, La, Ce, Sm, Gd, Tb, Yb, Hf, Th and U. A determination of the possible pollution sources has been made for the analyzed elements; namely: coal and oil combustion are the main sources of V, Ni, Co and As; vehicle exhaust and non-exhaust sources, as well as industrial emissions, are the main sources of Mn, Co, Cd and Ba; construction dust is the source of Ca, Mg and Sb; various industries are the sources of Cr and Ni; the dust from cement kilns and ash from biomass burning is responsible for K and Cl; two-stroke motor vehicles, galvanizing factories and tire wear are the sources of Zn; and Br may be emitted from burning wastes.
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Benchmarking PHITS for radiation dose assessment from fly ash-blended concrete using MCNP6 and ResRad-Build
Lam Duy Nhat, Le Huu Loi, Le Quang Vuong, Vu Tuan Minh, Ho Van Doanh, Phan Long Ho, Tran Thien Thanh, Hoang Duc Tam
Applied Radiation and Isotopes, vol. 234, p. 112658, Apr. 2026
Abstract
In this study, the PHITS Monte Carlo code is applied for the first time to evaluate indoor radiation exposure associated with fly ash–blended concrete, and its performance is systematically benchmarked against the widely used ResRad-Build program and MCNP6 code. A reference room conforming to RP-112 dimensions (5 m × 4 m × 2.8 m) was modeled, and eight concrete mixtures containing 0–50% fly ash were investigated. The activity concentrations of 226Ra, 232Th, and 40K, along with material composition ratios and densities, were used as input parameters for simulations with PHITS, ResRad-Build, and MCNP6. The annual effective doses calculated using PHITS ranged from 0.378 to 0.489 mSv.y−1. The maximum relative deviations between PHITS and MCNP6 and between PHITS and ResRad-Build were 5.9% and 7.9%, respectively. PHITS exhibited the closest agreement with the reference dose estimate derived from measured activity concentrations, with a maximum relative deviation of 3.6%. These findings clearly demonstrate that PHITS is a highly reliable and effective tool for assessing indoor radiation exposure from building materials.
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Background subtraction using the SNIP method enhanced by the Levenberg–Marquardt algorithm
Anh Nhi Le, Thanh Tai Chau, Ngoc Ba Vu, Thien Thanh Tran, Le Hao Cong, Van Tao Chau
Nuclear Instruments and Methods in Physics Research Section a Accelerators Spectrometers Detectors and Associated Equipment, 171544 (2026)
Abstract
In this study, a practical refinement of the SNIP method is proposed for background subtraction in HPGe γ-ray spectra. A single filter width determined from the detector specifications is used in Gaussian convolution to obtain preliminary peak parameters, which are then refined using the Levenberg–Marquardt (LM) algorithm to provide more reliable peak widths for SNIP background subtraction. The resulting method, referred to as LMSNIP, is evaluated using the 154Eu spectra measured at 25 cm and 5 cm. The reconstructed backgrounds are directly compared with those obtained using the adaptive SNIP approach, while the resulting net peak areas are compared with Genie2K. For the 25 cm spectrum, LMSNIP and adaptive SNIP provide generally similar background estimates. Under the more demanding 5 cm condition, however, LMSNIP yields a smoother and more stable baseline and generally better agreement with Genie2K for most investigated peaks. Additional validation using the 133Ba spectrum measured at 5 cm further shows that LMSNIP remains effective for a reference spectrum with different low-energy characteristics. These results support the applicability of LMSNIP to background reconstruction and net peak-area determination under the investigated close-geometry conditions.
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Background Radiation in some Quarries and Quarry Lakes in Binh Duong Province, Vietnam
Van Thang Nguyen, Nguyen Phong Thu Huynh, Huynh Thi Yen Hong, Truong Huu Ngan Thy, Huynh Truc Phuong, Cong Hao Le
Journal of Radioanalytical and Nuclear Chemistry(2022)
Abstract:
Operation of some quarries can release radioactive materials from the deep soil to other environments that potentially impact human health. The present study investigated concentrations of radon and other radionuclides in surface soil, air, and water around two quarries in the south of Vietnam. Indoor radon concentrations ranged between 6.19 Bq m-3 and 20.6 Bq m-3. In surface soil, the average concentrations of 40K, 226Ra, and 232Th were 387, 36.5, and 44.5 Bq kg− 1, respectively. In surface soil, the average values of radioactivity found for 40K, 226Ra, 238U, and 232Th were 2.65, 1.23, 1.12, and 1.22 mBq l-1, respectively. The results show that the radioactive levels in the quarry region are found higher than in the nearby area. However, these levels are not enough for a recommendation for public health.
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Phan Long Ho, Le Dinh Hung,Vu Tuan Minh,Dang Van Chinh, Tran Thien Thanh, Chau Van Tao
Assessment of physicochemical properties and radioactivity in groundwater at households living in bac Lieu province, vietnam
Phan Long Ho, Le Dinh Hung, Vu Tuan Minh, Nguyen Tran Bao Thanh, Dang Van Chinh, Le Hoang Minh, Tran Thien Thanh, Chau Van Tao
Environ Geochem Health
Abstract:
This paper presents findings on groundwater physiochemical composition and radioactivity levels in households in Bac Lieu province, Vietnam. Through discriminant analysis, it was observed that groundwater quality exhibits spatial variations corresponding to saline intrusion zones. The paired-samples T-tests revealed significantly different ratios of Ra-224, Ra-226, and Ra-228 isotopes between Na–Cl and Ca–Na–HCO3 water types. All three water types had a ratio of Ra-226/Ra-228 of approximately one, indicating the presence of groundwater aquifers beneath the crust and fluvial marine sediment. Furthermore, strong associations between sulfate and calcium suggest that CO2 enrichment in groundwater aquifers indicates anoxic aquatic environments. Twenty-five of the thirty-three evaluated samples exceeded the national technical regulations for domestic water quality with parameters such as chloride, sulfate, sodium, gross alpha, or total dissolved solids. Fifteen samples exceeded gross alpha's allowable contamination threshold of 0.1 Bq/L. The combination of Ra-226 and Ra-228 did not surpass the U.S. Environmental Protection Agency's recommended limit of 0.185 Bq/L. However, nineteen samples exhibited annual committed effective doses of radium isotopes for infants that exceeded the WHO recommendation of 0.1 mSv/year.
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