With a history of over fifty years of contributing to animal feed, fishmeal and fish oil are very well known ingredients which are manufactured from raw materials that are sourced from the natural environment. Being natural resources sourced from across the world, these resources can sometimes be exposed to naturally occurring contaminants of various types that might be in the soil, water, or air. Human activity is the main source of this contamination, which has a tendency to end up in the seas.

Regulatory frameworks exist at multiple levels at both national and international levels (eg: EFSA for food intended for direct human consumption, and CODEX alimentarius for feed for food producing animals).  Importantly, these regulations keep developing based on the state of the science as our understanding of threats grows and our ability to measure them improves. For some contaminants, the body of science is growing but is still in its relative infancy. The continuation of support for high quality scientific research to underpin national government policy decisions and any future regulation or management in this area is essential:

• Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a group of chemicals that are found in a variety of everyday products like packaging, cookware, clothes, and refrigerants. In January 2023, the European Commission introduced maximum levels (MLs) for PFAS in a range of food types (eggs, fish, milk, and meat products). No MLs presently exist for feeds or any feed ingredients, though this is a likely follow on. The current scientific understanding and technical methodologies needed to test for PFAS at the very low concentrations found in food are a very recent development.

• The challenge of microplastics (and nanoplastics) is global and affects the whole seafood supply chain. At this stage, we know that plastics and microplastics are ingested by marine life. What we don’t know is the level of risk attached to the ingestion for the consumer of seafood products that may contain plastics or microplastics. This area is another that is hampered by a lack of standardised analytical methodolgy.

• Cadmium makes up about 0.1 mg/kg of the Earth's crust and can be found in our environment and food.  Although cadmium is considered a toxic heavy metal for terrestrial organisms, it exhibits nutrient type distribution in the ocean with internal cycling of cadmium in the ocean controlled by biological activity. Field surveys of cadmium concentrations in marine organisms have clearly shown that some species accumulate higher levels of cadmium than others, with the the heavy metal typically being more concentrated in the viscera than the meat.

• Dioxins and dioxin-like compounds are a group of synthetic chemical compounds. Because dioxins are very stable, they have a very high tendency towards bioaccumulation and biomagnification in various aquatic organisms. The most important direct source for dioxins to the aquatic and marine environment is through deposition of airborne particle-bound dioxins. EU Regulations implemented in September 2012 stipulated measures to monitor and control dioxins in fats and oils. Fish oils containing higher levels of dioxins are treated with activated carbon, or other methods, to reduce the dioxin content before they can be used for feed or food purposes.
   
• Lead occurs in the environment both naturally and, to a greater extent, from anthropogenic activities such as mining and smelting, battery manufacturing and the use of leaded petrol (gasoline). Lead (Pb), another well known heavy metal, is present in the Earth’s crust in various forms. Lead contamination of food arises mainly from the environment or during food processing. Although lead exists in both organic and inorganic forms, only inorganic lead has been detected in food.