HEAVY METAL CONTAMINATION IN MARINE ENVIRONMENTS

 

Plans to rebuild Fjällbacka harbour in Tanum municipality lead to investigations into the heavy metal concentrations in surface sediments out of fears of contaminants spreading due to altered currents and water movements (Fahl, 2014; Jönsson, 2014). High concentrations of contaminants such as copper, lead and zinc were found, possibly originating from the use of antifouling paints containing these metals. Cadmium and mercury were also found.

 

Water circulation in the harbour are primarily a result of the Baltic and Jutska surface currents in the Skagerrak (Jönsson, 2014). Water circulation is mainly wind driven. Water in the harbour generally moves along the south-north axis with surface water from the Skagerrak moving north, then downwelling and moving back towards the south.

 

The surface sediments in the Fjällbacka harbour consist primarily of gyttje clay but there may also be some clay gyttja (Jönsson, 2014). Sediments are oxygenated down to a depth of 3 cm. Below, anoxic conditions dominate. In addition to the high heavy metal concentrations, anthropogenic influences can also be seen in the presence of plastics and coal. Sediments mostly exhibit a low degree of of compaction. This makes them susceptible to disturbances.