Contamination Near Chernobyl: radiocaesium, Lead and Mercury in Fish and Sediment Radiocaesium from Waters Within the 10 km Zone

Abstract

Samples of fish and sediments collected from waters within 10 km of the Chernobyl Nuclear Power Plant were analysed for radiocaesium and other atmospherically transported pollutants (lead (Pb) and mercury (Hg)) were measured in fish tissues. For comparison, fish muscle was also sampled from a less-contaminated area of the Kiev Reservoir and from a hatchery in Kiev. In sediments, 137Cs was the major gamma-emitting isotope, with concentrations of over 100 Bq g−1 in canals adjacent to the reactor and in ponds that were downwind during the accident. The radiocaesium distributions appeared non-normal, were very patchy and could vary by over 100% in samples collected metres to tens of metres apart. Fish muscle radiocaesium from ponds within 10 km of the power plant was in the range of 6–192 Bq g−1. The fish muscle radiocaesium concentrations were highest in ponds from the downwind sites and were correlated with the sediment radiocaesium concentrations. The lead and mercury concentrations in fish were relatively low (medians <0.8 μg Hg per g dry mass and <150 ng Pb per g dry mass), suggesting little contamination from lead applied to the burning reactor after the accident. The radiocaesium levels in fish in areas close to the reactor continue to be high enough to cause health concerns to humans that might utilize these resources.