Is Sewage Pollution Still a Major Threat to Our Oceans?

The grisly matter of raw sewage entering natural water bodies was a massive ocean issue in the 1980s and 1990s until new laws were introduced, enforcing the treatment of wastewater before its release into the environment. It seems astonishing that these laws were only implemented in the UK 30 years ago and prior to that, our oceans were seen as a vast expanse which could dilute and essentially make disappear our waste. Today, talk of sewage in ocean conservation circles seems to have fallen a little quieter as we focus on the newer issues of plastic pollution, overfishing and warming seas but does this mean that the problem of sewage has been solved? 

Unfortunately, the answer is a resounding no as multiple wastewater spills occur in our oceans around the world every day. In fact, sewage is one of the biggest contributors to ocean pollution, with more than 80% of global sewage flowing into our seas untreated. What is actually running into our oceans is a rather more complex cocktail than just sewage however, as untreated wastewater contains a plethora of substances harmful to both the environment and humans.

Wastewater is made up of sewage as well as grey water which runs away from our houses; this could include water used for showering, washing dishes or watering the garden. Industrial water is also included, which could contain chemicals, acids and heavy metals, as well as surface run off which is water running off the ground, collecting substances such as animal faeces, agricultural fertilisers and car oil along the way. All this water is collected in sewage systems and when the system gets overwhelmed, many authorities release this untreated chemical concoction into rivers and oceans to stop the dirty water flowing back up our drains. As you can imagine, this has devasting impacts on our natural environments. Coral reefs are a great example highlighting the impacts of all these harmful substances on the natural world.

Let’s start with the sewage itself. Sewage attracts bacteria which then break down the waste and in the process, use up large amounts of oxygen which can leave that local path of ocean lacking oxygen. When this happens, fish and other creatures struggle to thrive and in some extreme cases can cause a ‘dead zone’ where little is able to grow or survive. Even more shockingly, drugs consumed by humans can still be contained in our waste, meaning substances like antibiotics and hormones are floating around in the sea. Antibiotics, in particular, cause a problem for corals as they attack the natural community of bacteria which live in a mucus layer on the surface of the corals. These bacteria are healthy ones which work in the same way microbes do in our gut. With these bacteria suffering attack, corals may lose their natural protection and be left open to disease. In fact, in Florida around 20 years ago, there was an outbreak of white pox disease which caused the death of 70% of rare elkhorn corals in the area. This was attributed to viruses present in human sewage which was dumped untreated into the ocean.

Agricultural fertilisers are another major component of wastewater and can have detrimental effects in the ocean. Fertilisers are composed of nitrogen and phosphorous which do an excellent job of making plants grow faster, exactly what we want on land but unfortunately, they also have the same effect in the water. The high level of nutrients in fertilisers causes algae to blossom and bloom and as a result, the new clouds of algae block sunlight from marine plants which leaves them struggling to grow. When the algae dies, it takes with it a lot of the oxygen in the water, leaving marine animals struggling too and this can also lead to dead zones, such as the 7728 square mile area of the Gulf of Mexico which is now largely devoid of life.

If this wasn’t enough, industrial chemicals and heavy metals can cause coral bleaching whilst also causing diseases and reduced reproductive success in both corals and other marine creatures. These toxic substances can also be stored in the tissues of fish, polluting the seafood we enjoy consuming. Endocrine disruptors are chemicals which are found in plastic, detergents and cosmetics, meaning they easily enter the oceans from our own houses as we wash synthetic clothes with chemical washing powders and pour colourful shampoos and soaps down the drain. These chemicals are known to disrupt hormones in both animals and humans.

Over the last few years in particular, the number of people engaging with nature and exploring new hobbies in our watery habitats has increased massively, meaning the troubles of untreated wastewater are not just ones facing our marine plants and animals. Swimmers, surfers, paddleboarders, kayakers and many more are also at risk of this often overlooked pollution threat and in America alone, 3.5 million people become ill from polluted water every year, developing gastroenteritis or infections of the ear, throat or nose.

Take the UK for example, in 2019, there were over 200,000 discharges of untreated sewage into rivers and 2,000 discharges into coastal bathing waters during the bathing season of May to September. If this sounds like a high number, this only represents 30% of all discharges that occurred throughout the year. During the bathing season, sewage outputs are technically controlled to help protect human health and so outside of these months, discharges are much higher. Since 2010, water companies in the UK have been allowed to report their own levels of pollution, however many companies lack transparency and honesty and fail to report their spills at the time of occurrence, or ever in some cases. This lack of real-time data means that water-users are unaware of when their local water bodies are safe to enter. By law, water companies are only allowed to release untreated water when the sewage system is struggling to cope, however a mix of outdated sewage systems, growing populations and more frequent storm events means this is increasingly often. The issue of fatbergs, made from oils, fats and non-biodegradable items like nappies and wet wipes which are incorrectly flushed down sinks and toilets, is also adding to the problem. 

Positive change is on the horizon however as recently, one British water company received a record fine of £90,000,000 for the dumping of raw sewage into the waters off Kent. The company was found to be releasing untreated sewage in order to profit financially whilst also massively under-reporting the pollution they were causing, disregarding environmental and human health as well as hindering maritime industries such as the shellfish sector. With the UK now out of the EU, the previous environmental standards and frequent fines for poor water quality are a thing of the past but this lawsuit is a sign that Britain may just stay committed to protecting its oceans.

However, community action is still important to ensure the pressure stays on the government to make the right decisions whilst also making a difference at ground level. A community of passionate wild swimmers has recently won the battle to declare their local swimming spot on the River Wharfe near Ilkley a designated bathing site, the first river bathing site in the UK. This means that during the bathing season, water quality will have to be closely monitored and sewage discharges will be more tightly controlled. There are other simpler steps we can take at home to help reduce sewage pollution which include only flushing the three ps down the toilet and switching to more environmentally friendly soaps, washing powers and garden fertilisers. We can also avoid paving over our gardens or turning to artificial turf as neither of these materials absorb rainwater. By keeping natural environments like grass and trees, rainwater can be absorbed into the ground rather than run straight into our sewage systems and overwhelm them.

This idea of using green infrastructure to improve the sewage problem is also growing on a large scale across the world. Many are starting to see that creating bigger sewage systems will only solve the problem for the next decade or so whilst the process will be extremely expensive and carbon intensive. Instead, countries such as Sweden and China have rewilded parts of their land by reintroducing wetlands, ponds and green ditches which all act to trap water or slow down its journey through the landscape. This helps prevent flooding which is often when large amounts of sewage and wastewater are released into the sea. In Wales, a similar approach is taking place in order to stop polluted water spilling into their shellfish-rich waters and so far, the project is expected to cost a quarter of the amount needed for bigger sewer systems. In fact, reed beds are a largely underrated ecological feature as they provide the perfect place for bacteria and fungi to live. When sewage travels through the reeds, these microorganisms digest the organic matter in the water and leave it flowing out the other side much cleaner than when it arrived.

It seems that the issue of sewage and wastewater pollution is far from over but maybe the solution is simpler than we think and lies with passionate campaigning water lovers and a greener, wilder landscape. 

By Neve McCracken-Heywood