Bottom trawling resuspends sediment and releases bioavailable contaminants in a polluted fjord

Environ Pollut. 2012 Nov;170:232-41. doi: 10.1016/j.envpol.2012.06.019. Epub 2012 Jul 25.

Abstract

Sediments are sinks for contaminants in the world's oceans. At the same time, commercial bottom trawling is estimated to affect around 15 million km(2) of the world's seafloor every year. However, few studies have investigated whether this disturbance remobilises sediment-associated contaminants and, if so, whether these are bioavailable to aquatic organisms. This field study in a trawled contaminated Norwegian fjord showed that a single 1.8 km long trawl pass created a 3-5 million m(3) sediment plume containing around 9 t contaminated sediment; ie. 200 g dw m(-2) trawled, equivalent to c. 10% of the annual gross sedimentation rate. Substantial amounts of PCDD/Fs and non-ortho PCBs were released from the sediments, likely causing a semi-permanent contaminated sediment suspension in the bottom waters. PCDD/Fs from the sediments were also taken up by mussels which, during one month, accumulated them to levels above the EU maximum advised concentration for human consumption.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Benzofurans / analysis
  • Benzofurans / metabolism
  • Bivalvia / metabolism
  • Dibenzofurans, Polychlorinated
  • Environmental Monitoring*
  • Fisheries / instrumentation
  • Fisheries / methods*
  • Geologic Sediments / chemistry*
  • Polychlorinated Biphenyls / analysis
  • Polychlorinated Biphenyls / metabolism
  • Polychlorinated Dibenzodioxins / analogs & derivatives
  • Polychlorinated Dibenzodioxins / analysis
  • Polychlorinated Dibenzodioxins / metabolism
  • Sweden
  • Water Pollutants, Chemical / analysis*
  • Water Pollutants, Chemical / metabolism

Substances

  • Benzofurans
  • Dibenzofurans, Polychlorinated
  • Polychlorinated Dibenzodioxins
  • Water Pollutants, Chemical
  • Polychlorinated Biphenyls