When we think of polluted seas, more often than not we focus on plastic littering; images of plastic bottles and can holders floating on the ocean’s surface. But there’s so much more to it than that. Sewage disposal and toxic chemicals are also huge problems when it comes to marine pollution, and it’s an issue we really must direct more attention to.
When it comes to sewage disposal, many parts of the world leave sewage flows untreated or under treated, allowing this to enter the ocean. For example, 80% of urban sewage discharged into the Mediterranean Sea is untreated. This can cause a whole world of problems, for example human disease and eutrophication. You can read more about eutrophication here; my colleague Kathini wrote all about it in a previous blog post.
When toxic substances enter a body of water, they either dissolve, become suspended in water or get deposited on the bed of the water body. The resulting water pollution causes the quality of the water to deteriorate and affects aquatic ecosystems. This polluted water can then get discharged into rivers, meaning that pollutants enter groundwater, rivers, and other water bodies. This highly contaminated water that has potential to carry disease causing microbes then ultimately ends up in our households, which is obviously a huge problem.
However, it’s not all doom and gloom! There are things you can do to help. For example, in many countries there’s an ongoing campaign to ‘bag it and bin it, don’t flush it!’ in aim to protect rivers and seas by decreasing the number of disposable items flushed down items, such as cotton bud sticks, sanitary towels and napkins which can travel through the sewers and end up back on our beaches. Basically, avoid flushing anything down the toilet that is made of plastic or non biodegradable material!
On the other hand, toxic chemicals are a different story. Almost every marine organism, from the tiniest plankton to whales and polar bears, is contaminated with man made chemicals such as pesticides and chemicals used in common consumer products. These chemicals have either been dumped into the ocean previous to the dumping ban made by the London Dumping Convention in 1972, or they make their way into the sea during their manufacture, use or disposal. The chemicals can escape into the water, soil and air during these processes, as well as in accidental leaks or fires in products containing these chemicals.
“Tiny animals at the bottom of the food chain, such as plankton in the oceans, absorb the chemicals as they feed. Because they do not break down easily, the chemicals accumulate in these organisms, becoming much more concentrated in their bodies than in the surrounding water or soil. These organisms are eaten by small animals, and the concentration rises again. These animals are in turn eaten by larger animals, which can travel large distances with their even further increased chemical load.”
However, like all preventable causes, there’s a way we can all prevent this from continuing. For example, one website suggests using natural air fresheners such as fresh flowers rather than chemical sprays; using compost and preventing the use of herbicides and fungicides. Other websites recommend using recycled products, giving away paints to people who will use them, using chemical based products before they go bad, limiting the use of cars and motor vehicles.
There’s plenty we can do, if only we keep positive and keep looking for solutions, no matter how small scale they are!