Akkumulering av miljøgifter i blåskjell og semipermeable membraner i delområde 1 og deponiene ved Haakonsvern orlogsstasjon : oppfølgende undersøkelser

The bioaccumulation of PCBs in blue mussel and semipermeable membrane devices (SPMD) were studied after completion of cleanup efforts in subarea I at the naval base Haakonsvern. It was not possible to detect any reduction of the accumulation of PCBs in blue mussel and SPMD after finishing cleanup in subarea 1. The probably cause is the transport of seawater and organisms, which serve as food for blue mussel, into subarea I from the contaminated surroundings of subarea 1. lt is also possible that remnants of PCBs in the sediments of subarea i can be sufficient to maintain the concentration of dissolved PCBs in seawater. Subsequent to cleanup of subarea 1 the transport of PCBs from depository 1 has decreased at least by a factor two as measured by blue mussel and SPMD.

The environmental impact of PCBs seems to be the same in subarea 1, depository 2 and just outside depository 2 and this indicate that there is no transport of PCBs out of depository 2. The soluble fraction of PCBs in seawater as measured by SPMD is about twice as high in depository I compared with depository 2. In view of this concentration gradient of PCBs and the fact that the barrier between depository 1 and 2 only to some extent prevent transport of soluble PCBs, a small transport of PCBs Out from depository I into depository 2 can not be ruled out.