Faybishenko B, Nicholson T (eds) Shestopalov V, Bohuslavsky A, Bublias V | Groundwater vulnerability: Chernobyl nuclear disaster

Abstract

This volume written by Vyacheslav Shestopalov, Alexander Bohuslavsky and Volodymir Bublias describes the vulnerability of groundwater to contamination by harmful material on the ground surface and is based on a case study about radioactive isotopes (Cs, Sr) released from the Chernobyl nuclear power plant in the province of Kyiv (Kiev), Ukraine during the severe accident in April 1986. Groundwater vulnerability means the easiness of movement of harmful material from the land surface into groundwater aquifer, and is the term opposite to the groundwater protectability. The volume is composed of 6 chapters. In Chapter 1 several methods of estimating the groundwater vulnerability are reviewed. In most of those methods, the permeability of water in strata of an upper groundwater aquifer is estimated by postulating homogeneity of each stratum of the upper aquifer geologically, mineralogically, geophysically, geochemically, etc. In Chapter 2, the state of pollution by Cs and Sr around the Kyiv urban area including the Chernobyl Exclusion Zone is explained from the ground surface, groundwater and rock from core samples. However, the explanation is rather brief, and not enough for most of the readers to understand the level of pollution. In the following chapter, based on the observed fact that Cs had reached to upper groundwater aquifer within a shorter lapse of time after the accident than the time expected from permeability of unsaturated zone, the authors expected some preferential fast movement of water and/or radioactive material through localized vertical paths and called the sites of such paths as ‘‘preferential flow and migration zones, PFMZs’’. The area of Kyiv Oblast (Province) is mostly flat land where many depressions occur that range up to a few hundred meters in diameter and to 1.5 m in depth. The authors concluded that vertical rapid movement of infiltrating precipitation happens at the center (bottom) of such a depression, based on the observed facts such as emanation of radon, seismic anomaly, higher infiltration rate, higher groundwater level, lower concentration of dissolved component of groundwater, degradation of rock by leaching and others. In Chapter 4, the movement of Cs through the vertical path at the center of a depression is expressed by a one dimensional partial differential equation, and the solution by a finite element method is described with little detail. This method is applied in Chapter 5 in order to estimate the groundwater vulnerability to contamination by Chernobyl-born Cs and Sr. A map of the groundwater vulnerability in Kyiv Province and the Chernobyl Exclusion Zone is drawn. Also, the authors forecasted that the concentration of Chernobyl-born radioactive materials in the groundwater remain lower than the maximum allowable concentration for water supply purposes, especially drinking water according to the regulation in Ukraine that is equivalent to the worldwide regulation. Chapter 6 provides a short summary. The idea of fast infiltration of precipitation through a vertical path at the center of a depression is evaluated to be & Osamu Matsubaya ishiyama@gipc.akita-u.ac.jp