タグ「Soil contamination」
Title: α-Particle track investigation of the Chernobyl Nuclear Power Plant accident region soil samples
Author: L.L. Kashkarov, G.V. Kalinina, V.P. Perelygin
Reference: Radiation Measurements, Volume 36, Issues 1–6, June 2003, Pages 529-532
DOI: http://dx.doi.org/10.1016/S1350-4487(03)00199-9
Keywords: α Tracks; CZ plastic track detector; Highly-radioactive “hot” particles; Chernobyl accident region; Radio-nuclide soil contamination
Abstract: Results of α-particle track studies (Radiat. Meas. 25(1–4) (1995) 413; Radionuclides and Heavy metals in Environment, Vol. 5, 2001, Kluwer Academic Publisher, Dordrecht) indicate that the surface layer of the soil in the Chernobyl Nuclear Power Plant (NPP) accident region consists of thinly dispersed radionuclides and highly-radioactive “hot” particles (HPs). The latter contain nearly 2/3rds of the total α-activity of the contaminated soil. In the present report, the new results of continued HP α-activity characteristics are presented. The chief attempt made was to investigate size–frequency vs. α-activity distribution of HPs of size fraction ⩽10– . For the Hp-aggregates with ∼100– sizes, α-radio-nuclide heterogeneity was established. This is probably the result of formation of HP-aggregates during the second stage of the NPP accident process: in these HPs the presence of not only U and fission products of “fuel” origin has been revealed, but also of terrestrial matter components.
URL: http://www.sciencedirect.com/science/article/pii/S1350448703001999
Title: The effective source area of 90Sr for a stream near Chernobyl, Ukraine
Author: Rina Freed, Leslie Smith, Dmitri Bugai
Reference: Journal of Contaminant Hydrology, Volume 71, Issues 1–4, July 2004, Pages 1-26
DOI: http://dx.doi.org/10.1016/j.jconhyd.2003.07.002
Keywords: Chernobyl; Hydrologic contaminant transport; Non-point source; Soil contamination; Strontium-90
Abstract: Remediation of streams impacted by non-point source contaminants requires an understanding of both the areas within a watershed that are contributing contamination to streams and the pathways of contaminant migration to streams. From 1998 to 2002, we studied the migration of 90Sr in the Borschi watershed, a small (8.5 km2) catchment three km south of the Chernobyl Nuclear Power Plant, Ukraine. Fuel particles, distributed in a heterogeneous pattern across the watershed, are weathering and releasing 90Sr from the fuel matrix. Depletion of 90Sr, evaluated in comparison to the immobile fission product europium-154, is occurring in the channel and wetland sediment. Channel sediments are uniformly depleted in 90Sr with depth. In wetland sediments, there is a zone of depletion in the top10 cm and a zone of accumulation at depths from 10 to 25 cm. Estimates of 90Sr depletion are used to map the effective source area that has contributed 90Sr loading to the main channel. The effective source area includes channel bottom sediments, a wetland in the central region of the watershed, and periodically flooded soils surrounding the wetland. The total depletion from the effective source area is estimated to be 36±7×1010 Bq. Based on observations of stream flow rate and water quality in 1999–2001, the annual 90Sr removal rate from the watershed is estimated to be 1.4±0.2×1010 or 1.5% of the inventory per year. When extrapolated over a 15-year period following the Chernobyl accident, the last value is in reasonable agreement with the estimated depletion of the source area based on 90Sr/154Eu ratios. The 90Sr yearly leaching rate considering the whole watershed is 0.2% while the 90Sr leaching rate considering the effective source area is an order of magnitude higher. Most of the 90Sr release in the watershed has originated from an effective source area of 0.62 km2, or 7% of the watershed area.
URL: http://www.sciencedirect.com/science/article/pii/S0169772203002225
Title: Soil contamination with 90Sr in the near zone of the Chernobyl accident
Author: V.A Kashparov, S.M Lundin, Yu.V Khomutinin, S.P Kaminsky, S.E Levchuk, V.P Protsak, A.M Kadygrib, S.I Zvarich, V.I Yoschenko, J Tschiersch
Reference: Journal of Environmental Radioactivity, Volume 56, Issue 3, 2001, Pages 285-298
DOI: http://dx.doi.org/10.1016/S0265-931X(00)00207-1
Keywords: Soil contamination; 90Sr; Chernobyl; 30 km exclusion zone; Map
Abstract: Representative large-scale soil sampling on a regular grid of step width about 1 km was carried out for the first time in the near zone of the Chernobyl accident (radius 36 km). An integrated map of terrestrial 90Sr contamination density in the 30 km exclusion zone (scale 1 : 200,000) has been created from the analysed samples. Maps of the main agrochemical characteristics of the soils, which determine the fuel particle dissolution rates and the contamination of vegetation, were produced. The total contents of 90Sr on the ground surface of the 30 km zone in Ukraine (without the reactor site and the radioactive waste storages) was about 810 TBq (8.1×10+14 Bq) in 1997, which corresponds to 0.4–0.5% of the Chernobyl reactor inventory at the time of the accident. This assessment is 3–4 times lower than previous estimates.
URL: http://www.sciencedirect.com/science/article/pii/S0265931X00002071
