Interaction of dissolved radionuclides with organic matter in prealpine freshwater lakes

Summary

The behaviour of ¹³⁷Cs, ¹⁰⁶Ru and ¹²⁵Sb radionuclides from the Chernobyl fallout is compared between Lake Constance and two neighboured small lakes (Vorsee and Schreckensee) with high organic loads. Whereas in both types of lakes indications for the predominant interaction of anionically speciated ¹⁰⁶Ru and ¹²⁵Sb with organic matter were found, ¹³⁷Cs was associated with organic matter only in the small lakes resulting in a persistent bioavailability. In Lake Constance, the almost exclusive binding of¹³ Cs to clay minerals in the sediment allows its application as tracer for recent sediment formation.