Tributyl tin (TBT)
Tributyl tin is used as an anti-fouling paint for boats. It prevents barnacles and other sea creatures from attaching themselves to the boat and and damaging it or slowing it down. TBT is highly toxic, however, and can dissolve from the boat’s surface into the water around it. In areas where TBT concentration is high, all life can be wiped out. In areas with lower concentrations there may still be detrimental effects which cause deformities - female dog whelks grow a penis and are then unable to mate and lay eggs. TBT use has now been restricted to boats of a certain size and purpose.

Chemical runoff
Modern farming methods use fertilisers and pesticides to optimise crop growth which can leach into rivers and coastal environments. Pesticides may kill off some invertebrate life along the coast, while the phosphates in fertilisers can encourage the growth of dense algae, smothering habitats and reducing diversity.

Chemicals that enter the drains of our cities and towns also make their way to the coast. These include oil and petrochemical runoff from roads which may smother or stifle breathing and feeding parts in small invertebrates, or be toxic to larger animals which eat them. Products such as washing up liquid which are also often high in phosphates regularly enter the drainage systems. All these chemicals can concentrate in rock pools, decimating life in these microhabitats.

Tar deposits and oil
Tar deposits and oil originate from the same pollutant sources: leaks from industrial sites, refineries and discharges from ships. Occasionally a damaged oil tanker will spew out crude oil and cover the coast. Many animals are vulnerable to poisoning by ingesting oil. Seabirds can find their feathers matted, which not only makes them unable to fly, but also ruins their insulating properties which can lead to exposure and then death. Plants can also be smothered.

On beaches, particles of tar find their way in between the grains of sand and spread through the whole area. This can affect burrowing animals like the lugworm or sea potato, damaging their feeding parts and reducing the amount of available food. Exposed beaches are washed more often by storm waters, allowing the tar deposits to be dispersed from the coast.

Dioxins
Dioxins originate from incinerators, industrial activity and traffic and persist in the environment for a long time. They are stored in the fat of animals and concentrate up the food chain so that the top predators can carry high concentrations. Long-term exposure in humans may affect the liver and impair the immune system.