The UK's Food Standards Agency has published results of surveys of the levels of various contaminants in fish, shellfish and fish oils.
  
The FSA said levels were found to be low and it therefore continues to advise that as part of a healthy balanced diet the majority of people should eat more fish.

The five surveys, which were carried out as part of routine monitoring, show that, where comparisons are possible, levels of contaminants are similar to or have decreased since they were previously measured.

Current FSA advice is that people should eat at least two portions of fish a week, one of which should be oily. Fish and shellfish are rich in protein and minerals, and oily fish is rich in long-chain omega 3 fatty acids, which reduce the risk of death from heart disease.

Fish and shellfish were collected or harvested from a range of locations around the UK and samples taken from those on sale. A range of substances were analysed, including lead, mercury and cadmium, organotins, which are present in sea water from marine paints, and polycyclic aromatic hydrocarbons (PAHs), which come from oil and combustion processes. Some of these substances can occur naturally at low levels, while others are present as a result of environmental pollution.

The European Commission has set legal limits for some contaminants in food that take into account safety and other considerations, such as measures that should be taken by industry to reduce the levels. Occasional consumption of products that slightly exceed these limits would not be a concern for people's health, the FSA said.