Importance of the Aquatic Detritus Foodweb in the Transfer of Radionuclides From Water to Higher Trophic Levels

Abstract

Uptake of radionuclides from water to decaying elm-leaf discs and their transfer to the amphipod Gammarus lacustris was investigated. Uptake by decomposing elm leaves is microbially mediated. Uptake coefficients, k, for G. lacustris fed contaminated leaf discs were 3.66ˑd^-1 for ⁶⁰Co, 4.34ˑd^-1 for ¹³¹I and 9.74ˑd^-1 for ¹³⁴Cs, whereas loss rates were -1.08ˑd^-1 for ⁶⁰Co, -1.07ˑd^-1 for ¹³¹I and -1.04ˑd^-1 for ¹³⁴Cs. Assimilation efficiencies were 11% for leaf material, 53% for ⁶⁰Co, 55% for ¹³¹I and 75% for ¹³⁴Cs. These results indicate that there is considerable potential for the transfer of radionuclides to higher trophic levels by the detritus-food web.