SARF026: Evaluation of the impact of copper released to the environment from the marine cage fish farms

Start Date: 1/2/07
End Date: 01/08/09
Main Contractor(s): University of Aberdeen
Other Sponsor(s):  

Objectives

1) Use a transect sampling approach to measure the Cu concentrations in sediments around marine cage fish farms in Northwest Scotland.

2) Measure (also using a transect approach) the Cu concentrations in sediments, associated invertebrates, and brown algae on rocky headlands, and of beaches adjacent to the selected fish farms to assess the dynamics and impact of any transfer of Cu.

3) Use a solid phase and interstitial pore water phase ecotoxicity test (based on the response of the marine, luminescent, bacterial biosensor, Vibrio fischeri) to assess the bioavailability of the copper associated with Cu contaminated sediments.

4) Use the transect sampling approach to measure Cu concentrations and resupply fluxes in seawater (using diffusive gradients in thin films, DGT) around marine cage fish farms in Northwest Scotland.

5) Experimentally determine the effects of labile Cu (using at least three environmentally relevant concentrations) upon phytoplankton primary productivity at four different light intensities. Each culture will be run in triplicate, with duplicate analysis of each. This technique determines productivity through determination of the uptake of isotopically enriched 13C.

6) Examine the factors controlling desorption of Cu from sediments in order to address how these potential biogeochemical changes affect the impact of the fish farm released copper and to predict the potential for recovery of impacted sites.

7) Generate a simple working regression model using sediment chemistry for the evaluation of the impact of fish farm derived copper contamination.


Summary

Copper is associated with marine cage fish farms in a number of ways ranging from antifoulants on cages and boats, to part of the wastes, which disperse from the fish farms. It is known to be toxic to a number of marine species, and this project aims to assess the multitrophic impact of copper releases into the environment from marine fish farms. We will: 1) Use a transect sampling approach to measure the Cu concentrations in seawater (by diffusive gradients in thin films, DGT) and sediments around marine cage fish farms in Northwest Scotland through collaboration with a fish farm co-operative. The transect orientation and size will be determined by tidal current direction and strength. The Cu concentrations will be related to physicochemical properties along the transects. 2) Measure (also using a transect approach) the Cu concentrations in sediments, associated invertebrates, and brown algae on rocky headlands, of beaches adjacent to the selected fish farms (as well as for a locally matched control site) to assess dynamics and impact of any transfer of Cu. Again, the Cu concentrations will be related to the sediment properties along the transects. 3) Use a solid phase and interstitial pore water phase ecotoxicity test (based on the response of the marine, luminescent, bacterial biosensor, Vibrio fischeri) to assess the bioavailability of the copper associated with Cu contaminated sediments. 4) Use of diffusion gradient thin film analysis coupled to ICPMS to determine the behaviour of Cu within this environmental matrix. 5) Experimentally determine the effects of labile Cu (at environmentally relevant concentrations) upon phytoplankton primary productivity under differing light intensities. 6) Assess the factors controlling desorption of Cu from sediments to address the impact of potential biogeochemical change on the impact of the fish farm released copper as well as the prediction of the potential for recovery of impacted sites. 7) Generate a simple working regression model using sediment chemistry for the evaluation of the impact of fish farm derived copper contamination. This will involve using Cu (as well as other heavy metals as appropriate) concentrations in sediments in addition to organic carbon concentrations and the proportion of clay and fine, silt-sized particles (less than 63 microns in diameter).