Based on theoretical considerations, the pollutant trapping efficiency
(PTE) of a river section was introduced to assess sediment contaminat
ion from pollutant discharge. Under simplified assumptions, PTE can be
calculated by the sedimentation of suspended particulate matter (SPM)
, the inflowing concentration of SPM and the solid-water partition coe
fficient K-d. Regarding a more complex field case, a one-dimensional f
low and transport model was applied to a lock-regulated section of the
Neckar River, Germany. Long-term simulations (1950-1994) were carried
out (a) to analyse the temporal development of sediment contamination
and (b) to quantify the dependence of the PTE of cadmium on K-d and t
he Damkoehler number, characterizing the time scale of the adsorption
process with respect to the water residence time in the regarded river
section. Sediment contamination by Cd shows a strong response to the
decrease of Cd emission in the past. In the case of rapid adsorption,
sediment contamination increases non-linearly with rising partition co
efficient. This agrees qualitatively with the formula derived from the
oretical considerations. At the measured kinetic adsorption rates, che
mical equilibrium of solid-water partitioning is reached at low to mod
erate discharge, and sediment contamination in the river reservoir is
determined by the hydraulic trapping of the polluted SPM. (C) 1998 IAW
Q. Published by Elsevier Science Ltd.