One of the main pressures affecting the marine environment today results from the release and subsequent negative effects of contaminants into marine environments. Contaminants are defined in EU legislation as: “substances (i.e. chemical elements and compounds) or groups of substances that are toxic, persistent and liable to bioaccumulate and other substances or groups of substances which give rise to an equivalent level of concern” (Water Framework Directive, Article 2(29)).
Contaminants causing particular concern include pesticides, pharmaceutical agents (e.g. antibiotics, non-steroidal anti-inflammatory drugs (NSAIDs), analgesic drugs, lipid-lowering drugs, oestrogen-containing medication), heavy metals (e.g. mercury, arsenic, lead) and anti-foulants (e.g. from paint used on the bottom of a boats to prevent fouling).
Contamination of the marine environment arises from direct releases, land-based river runoff or atmospheric deposition. Contaminant pollution can result in serious adverse effects on ecosystems and eventually on human health through the process of ‘bioaccumulation’. Bioaccumulation begins with contamination of animals low in the marine food chain, which are then eaten in large quantities by bigger predatory animals. Toxins bioaccumulate in prey and are then passed on to animals (usually a larger fish or marine mammals) that prey on them which, in turn, may be consumed by an even larger animal. These contaminants increase in concentration as they climb the food chain through a process known as “biomagnification” until finally, a contaminated animal may be consumed by a human being.
Different chemicals affect human health in different ways. It is believed that sufficient consumption of contaminated food could lead to human health problems, for example hormonal problems, reproductive problems, nervous system damage and kidney damage.