Remediation of 150 000 m(3) of sediment containing 400 kg PCB was perf
ormed by suction dredging in a small lake in Sweden in the summers of
1993 and 1994. Upon project completion calculations indicated that 97%
of the PCB was deposited in a landfill with subsequent low transport
to the surroundings, and that 2.9 kg was left in the lake sediment. Co
ncentrations of PCB that were measured weekly in the water leaving the
lake were 12 ng/L (geometric mean) during dredging, not exceeding 30
ng/L and not significantly higher than in investigations preceeding th
e remedial action. The concentration of PCB was negatively correlated
to water discharge and positively correlated to water temperature. PCB
transport in the river was correlated to water discharge but not to t
he dredging activity. During dredging of the most contaminated part of
the lake, the dredging area was screened off by a geotextile silt cur
tain that reduced leakage of PCB to the river downstream.