Page 169 - Soil and water contamination, 2nd edition

156 Soil and Water Contamination

of local or regional concern. However, some of them have led to continental or even global
contamination by various radionuclides . Table 8.7 lists some of the major nuclear accidents.
The most serious nuclear accident to date was at Chernobyl. During the explosion in
reactor 4 and the subsequent fire, which lasted for 10 days, radioactive contamination spread
over large area in Ukraine, Belarus, Russia, and the rest of Europe. From a radioecological
perspective, the 1760 PBq of the short-lived 131 I was of most concern in the first weeks
90
following the accident. Later, attention shifted to 137 Cs and Sr, which are longer lived
and are the main contributors to internal and external doses to humans in the long term.
137
Figure 8.3 shows the spatial distribution of soil contamination in soil by Cs in Europe.
On 11 March 2011, a magnitude 9.0 undersea earthquake off the Pacific coast of
Tōhoku triggered a tsunami that hit the coast of north-eastern Japan. The waves, which
were up to about 14 m high, caused the Fukushima I Nuclear Power Plant (also known as
the Fukushima Daiichi Nuclear Power Plant) to become disconnected from the power grid

Figure 8.4 Cs-137 deposition in and around Japan in the period March 20 – April 19, 2011 following the
Fukushima accident. Adapted from Yasunari et al. (2011).

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