Iskanje po repozitoriju

A+ | A- | | SLO | ENG

Povzetek: Children’s lead exposure in three mining-impacted residential areas (Črna, Mežica and Žerjav) was modelled using the Integrated Exposure Uptake Biokinetic Model for Lead in Children (IEUBK). Site-specific environmental and dietary Pb source values were determined for modelling. For the first time, dietary exposure from both market and local foods was studied in detail. Children (Group 1: 24–36 and Group 2: 36–48 months) geometric mean blood lead levels (BLLs) were predicted and lead uptake from multiple sources was quantified according to the different dietary exposure scenarios. Biomonitoring data were used for validation. Site-specific soil, house dust and local food Pb contents are higher than legislative and background levels, remaining a cause for concern. Drinking tap water concentrations and outdoor air contents were found in acceptable levels. The determined dietary exposures, ranging from 0.7 to 3.3 µg/kg bw/day, were above the benchmark dose level of 0.5 µg/kg bw/day for developmental neurotoxicity set for Pb in children, indicating a health concern. In general, the estimated BLLs matched reasonably well with the observed BLLs in the Črna and Mežica area for both age groups and in the Žerjav area for Group 2. For Group 1, in the Žerjav area, the output of the IEUBK model overestimated the actual BLLs of the children. For both groups, the primary exposure pathway in Žerjav is from soil/dust, ranging from 55.3 to 84.8%. In Črna and Mežica, soil/dust exposure ranged between 24.2 and 57.8% and between 26.4 and 61.7%, respectively, indicating that dietary exposure predominates when local foods are included. The results of our study also suggest that using the IEUBK default diet value would reduce the dietary exposure up to 25.2% in Črna, 24.2% in Mežica and 8.6% in Žerjav. One of the main findings is that a diet containing local foods can be an important source of lead in mining-contaminated areas.
Ključne besede: IEUBK model, blood lead level, soil, house dust, dietary exposure, risk assessment
Objavljeno v DiRROS: 18.09.2025; Ogledov: 614; Prenosov: 214
Celotno besedilo (2,30 MB)

Povzetek: Owing to their anoxic environment, peatlands play an important role in the preservation of records documenting past atmospheric depositions. To determine past records, data on peat stratigraphy and bog development are needed. Ground penetrating radar (GPR) was used to determine the peat thickness and morphology of the Šijec bog on the Pokljuka plateau in Slovenia, which will serve as a basis for further geochemical studies. Information on the stratigraphy below the peat/clay boundary was acquired by applying electrical resistivity tomography (ERT). The GPR results reveal four depressions within the peat bog, which are separated by elevated ridges. Within the depressions the peat reaches a depth of 6–9 m. The edges of the bog are flat, with peat thickness ranging from 2 to 4 m. The reach of the GPR was complemented with manual peat probing. A comparison of the depths obtained using GPR and the peat probe reveals that the results of both methods correspond well in most locations. The ERT indicated similar peat depths; peat responds with high electrical resistivity. In contrast, clayey sediments with low resistivity are found below the peat. The peat depressions are underlain with larger clayey depressions reaching more than 20 m in thickness and represent lake sediments. The complementary geophysical methods proved to be an efficient approach with which we can delineate the peat morphology and the underlying stratigraphy. Both indicate bog formation from a lake with four deeper depressions, that are separated by glacial deposits. The results presented here show the potential for geophysical methods to infer formational processes in peatlands, showing the presence of a series of isolated basins that later coalesced into a single peat landform. This interpretation is consistent with previous conceptual models from studies in boreal regions.
Ključne besede: peatland, ground penetrating radar, electrical resistivity tomography, peat probing, peat thickness
Objavljeno v DiRROS: 07.07.2022; Ogledov: 1840; Prenosov: 876
Celotno besedilo (23,80 MB)