#OctopusStory and Chemical Pollution in the Marine Environment

_{By Amelia Corvin-Czarnodolski, Marine Champion for the Hampshire and Isle of Wight Wildlife Trust.}

The marine environment and its inhabitants are facing an increasing threat from human interference and, according to the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), pollution is one of the 5 main causes of the biodiversity crisis.

Most of us have seen huge oil spills on the news and the devastating effects they can have on wildlife, but did you know that chemical pollution encompasses all toxic fluids that are released into the ocean, many of which are lesser-known? In fact, oil spills only account for around 12% of the oil pollution in the ocean (the remainder from dumping, shipping, travel and wastewater drains), and there are a whole range of other chemical substances that pose a threat to marine life.

Most chemical pollutants reach our oceans via rivers, streams, and estuaries, often damaging local ecosystems along the way. One example of this is agricultural run-off from herbicides, pesticides, and fertilisers. Pesticides and herbicides are sprayed onto crops to repel or kill unwanted plants and animals, so they are often very toxic and when it rains, easily washed from the soil into nearby water bodies. Like a lot of man-made chemicals, they are insoluble so they don’t dissolve in water and instead can be absorbed into the tissues and fats of aquatic species. These chemicals can then build up to dangerous concentrations in the food chain, with the species at the top usually suffering the most. One example of this trophic transfer through the food chain is DDT – an insecticide responsible for the reproductive failure of predatory seabirds such as the brown pelican, double-crested cormorant, and the bald eagle. DDT was found to inhibit the ability of these birds to produce strong eggshells after eating contaminated fish, meaning the eggs often failed to hatch.

Fertilizers have a different effect – an excess of nutrients (mainly nitrogen and phosphorus) are released into the marine ecosystem and cause algal blooms. Algae are vital to life on earth and contribute massively to global carbon sequestration and oxygen production. However, surplus nutrients in the water can cause algae to grow out of control and reproduce very rapidly, often covering large surfaces of water and preventing aquatic species from receiving the sunlight and oxygen they need to survive. When these algae die, they are also decomposed by bacteria which consume the oxygen in the water and make it uninhabitable for fish and other aquatic species – this is called a ‘dead zone’. An example of this can be seen in the Gulf of Mexico where there is an area of around 6000 square miles, fed by fertilizer and sewage washed out via the Mississippi River, that is unable to sustain aerobic life. Some algae are also toxic and these toxic algal blooms have been responsible for numerous marine life casualties, including species such as turtles, dolphins and manatees.

Another source of chemical pollution is industry waste such as sewage and discarded chemicals from factories. Like fertilizers, sewage can contribute to algal blooms, but it can also release other harmful substances into the oceans. For example, medical products can be discharged through sewage and the bioaccumulation of these pharmaceuticals has been linked to fertility problems in fish. Another instance of bioaccumulation was the release of methyl mercury from a Japanese factory that built up to lethal levels in the food chain and lead to mercury poisoning in over 2000 people and the death of 1000 more as a result of eating contaminated seafood.

But it isn’t just farms, factories, oil companies and sewage works that are contributing to chemical pollution of the marine environment – our individual choices and actions also have an effect. Even household products like sun cream contain harmful ingredients such as oxybenzone which can cause huge problems for environmentally delicate habitats such as coral reefs; they contain nanoparticles that can interrupt the growth and reproduction of corals, ultimately leading to coral bleaching.

So, what has been done to help reduce chemical pollutants in our environment, and what further actions are needed to protect our marine life?

In the UK, we have the Environment Agency (EA) and the Environmental Permitting Regime (EPR) who monitor and regulate pollution in local water sources. Chemicals such as DDT have been banned in many nations, however their use in underdeveloped countries still poses a great risk to marine wildlife. Whilst oil spills have reduced in recent years due to better technology and policies, there is still much to be done.

With regard to farming practises, the new UK agri-environment scheme will hopefully encourage farmers to take greater action for clean, safe water and reduce agricultural run-off. Now may also be the time to start moving away from using intensive chemicals on farms and start having a more wildlife-friendly approach to agriculture.

But more monitoring and research is required to investigate chemical pollutants, their effect on the marine environment, and how we can combat them. Although some clean-up efforts have taken place in isolated areas, restoration is very difficult since pollutants get trapped in marine sediment. We need global government action to promote the responsible usage of chemicals, reduce oil spillages, and introduce more regulations and consequences for polluting the environment. On an individual scale, we as consumers can influence the chemical industry by refusing to purchase products from the biggest industrial polluters, as well as buying more eco-friendly household products which contain natural ingredients. This can reduce the harmful substances washed away through our drains and using ‘reef-safe’ sun cream near water can help protect these vital ecosystems.

Our collective actions today will hopefully influence the state of marine life in the future.

By Amelia Corvin-Czarnodolski, Marine Champion for the Hampshire and Isle of Wight Wildlife Trust.