Miljörisker sjunkna vrak II. Undersökningsmetoder och miljöaspekter
Report, 2015
During 2015 the Swedish Maritime Administration continued the second phase of the
governmental task Environmental risks from sunken wrecks which first report was finalized
2014-10-31 (Dnr: 1399-14-01942-6).
The main conclusions from the 2014 report remain; for future handling of potentially polluting
shipwrecks it is recommended that the Swedish Agency for Water and Marine Management is
given a coordinating responsibility in close cooperation with other competent national
authorities, such as Swedish Maritime Administration, Swedish Coastguard, Swedish National
Maritime Museums, the Geological Survey of Sweden, SMHI, Swedish EPA, and Swedish
Civil Contingencies Agency. Through coordination of wreck related operations and activities
within the concerned competent authorities’ ordinary areas of responsibility, resource
efficiency is improved. The estimated extra cost for implementation of a national strategy for
handling of the wrecks are estimated to be 10-15 MSEK which should be allocated to the
competent authorities by the Swedish Agency for Water and Marine Management.
The conclusions from 2014 was reinforced during 2015, e.g. through the validation of the risk
assessment model VRAKA, which is now available in a first operative version. Additional
ecotoxicological experiments on the development of tolerance against PAHs in meiofauna and
microorganism communities were conducted in a field study in Brofjorden. The main
conclusions from this work is that comprehensive analyzes of PAHs should include alkylated
PAHs, and that exposure to PAHs over time can lead to tolerance development in ammonium
oxidizing bacteria, at the expense of their ability to perform the essential ecosystem service
nitrification.
Continued measurements of the bottom currents were made at the wrecks Villon and Skytteren,
and at the dumping area west of Måseskär. Measurement series yielded important information
on how measuring equipment at the wreck can be deployed in an optimized way in future
monitoring program; to calculate the possible spreading of pollution from a wreck, current
measurements should be performed upstream from the wreck site, while sensors for the
detection of, for example, oil should be put into the turbulence downstream of the wreck.
The current measurement instruments (RDCP) deployed at the Måseskär dump site was trawled
up after only three weeks of measurements, but still gave valuable information on the extensive
bottom trawling that resuspend (stir up) sediments. Earlier geochemical surveys have shown
significantly elevated arsenic concentrations in the area and sediment resuspension greatly
increased the risk for spread of any contaminants in the area. Trawling is not prohibited in the
area, and the current lack of knowledge regarding potential effects on human health when
consuming seafood from dump areas calls for reflection upon the suitability of trawling in the
area.
In addition to the current measurements Swedish Maritime Administration and the Swedish
Navy conducted hydrographic survey with multibeam and side scan sonar and ROV
investigation of the wrecks in the dumping area at Måseskär. 28 wrecks were found, and ROV
investigation showed cargo holds with dumped torpedoes or mines and other containers in some
Sjöfartsverket
Dnr: 1399-14-01942-15
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of the wrecks. There is some discrepancy between the previously measured elevated arsenic
concentrations in the Måseskär area and recently presented data from historical archives that
does not support the theory that chemical weapons were dumped in the area. However, there is
a very good correlation between the dominant current direction in the area, and the highest
measured arsenic concentrations in the area downstream of the wrecks, suggesting some form
of arsenic source in the area.