在所有环境区隔中都可以找到原始放射性核素。由于燃煤发电厂(CFPP)可能是额外的放射性核素污染源,因为煤含有天然放射性同位素,如238U(226Ra)和232Th。这项研究调查了以前重工业活动可能造成的放射性核素污染的影响,即以前的当地燃煤发电厂,在Salgótarján的城市土壤和阁楼灰尘中,匈牙利。即使在今天,工业副产品,例如,粉煤灰,在这个城市对居民构成重大威胁。总共36个阁楼灰尘样本(家庭住宅,幼儿园,教堂和block堡)被收集和19个城市土壤样本(游乐场,幼儿园,公园和其他)从相应的阁楼灰尘采样点选择不超过500m。此外,还收集了粉煤灰和棕色森林土壤样本,以区分居民区的人为来源和地质来源。取样的房子,建于1890年至1990年之间,被认为是阁楼灰尘长期积累的代表性采样点。总U的平均值,阁楼灰尘和城市土壤样品中的Th和Cs(mgkg-1)以及K(m/m%)的浓度分别为2.4、3.6、1.7和0.6以及1.1、4.4、1.2和0.3,使用ICP-MS测量。226Ra的平均活性浓度,232Th,阁楼灰尘和城市土壤样品中的40K和137Cs分别为43.3、34.0、534.4和88.5和25.1、32.8、386.4和5.6Bqkg-1,通过使用具有阱型HPGe和n型同轴HPGe探测器的低背景铁室。元素组成(U,Th)和活性浓度(226Ra,232Th)随着采样点与CFPP的距离的减小,在两种研究介质中CFPP中的粉煤灰含量都增加了。特别是两个异常的阁楼粉尘样品显示出226Ra:145和143,232Th:83和94Bqkg-1的明显高活性浓度,可以认为是未风化的粉煤灰的代表。从城市土壤中获得的总吸收γ剂量率(D)和年有效剂量(E)表明CFPP的存在,粉煤灰锥和渣堆不会导致Salgótarján的背景辐射水平增加。然而,与城市土壤相比,所研究的放射性核素的浓度要高得多(232Th除外),并且在阁楼灰尘样品中表现出更高的变异性。研究表明,阁楼灰尘由于其与城市土壤不同的化学和物理特性,保留了长期大气沉积的不受干扰的“指纹”。
Primordial radionuclides can be found in all environmental compartments. Since coal-fired power plants (CFPP) can be a source of additional radionuclide contamination because coal contains natural radioactive isotopes such as 238U (226Ra) and 232Th. This study investigated the impact of such possible radionuclide contamination from former heavy industrial activities, namely a former local coal-fired power plant, in urban soils and attic dust in Salgótarján, Hungary. Even today, industrial by-products, e.g., coal ash, in this city represent significant threat to its residents. A total of 36 attic dust samples (family houses, kindergartens, churches and blockhouses) were collected and 19 urban soil samples (playgrounds, kindergartens, parks and others) were selected no further than 500 m from the corresponding attic dust sampling sites. Additionally, a coal ash and a brown forest soil sample were also collected to differentiate between the anthropogenic and geogenic sources in the residential area. The sampled houses, built between 1890 and 1990, are considered to be representative sampling sites for long-term accumulations of attic dust. The mean values of the total U, Th and Cs (mg kg-1) concentrations as well as those of K (m/m %) in attic dust and urban soil samples are 2.4, 3.6, 1.7 and 0.6 and 1.1, 4.4, 1.2 and 0.3, respectively, measured using ICP-MS. The mean activity concentrations of 226Ra, 232Th, 40K and 137Cs in attic dust and urban soil samples are 43.3, 34.0, 534.4 and 88.5 and 25.1, 32.8, 386.4 and 5.6 Bq kg-1, respectively, by using a low-background iron chamber with a well-type HPGe and a n-type coaxial HPGe detector. The elemental compositions (U, Th) and activity concentrations (226Ra, 232Th) along with their abundances in coal ash from the CFPP increase in both studied media as the distance of the sampling sites from the CFPP decreases. Two outlier attic dust samples in particular show significantly high activity concentrations of 226Ra: 145 and 143, of 232Th: 83 and 94 Bq kg-1, which can be considered as a proxy of unweathered coal ash. The calculated total absorbed gamma dose rate (D) and annual effective dose (E) received from urban soils indicate that the presence of the CFPP, coal ash cone and slag dumps does not cause an increase in the level of background radiation in Salgótarján. However, the concentrations of the studied radionuclides are much higher (except for 232Th) and exhibit higher degree of variability in the samples of attic dustthan in those of urban soils. The study suggests that attic dust preserves the undisturbed \'fingerprints\' of long-term atmospheric deposition thanks to its chemical and physical properties unlike urban soil.