In the first of its kind, a study into plastic pollution in the River Nile has found that three-quarters of sampled fish contained microplastics, sparking concern about the implications of plastic entering the human food chain.
Conducted in collaboration with Sky News, the study found that over 75% of the 43 fish sampled contained microplastics in their gastrointestinal tracts. From these fish, 211 items of plastic were recovered. The highest number of microplastics recovered from a single fish was 20 individual items.
The researchers say that the amount of microplastics found in fish from the Nile River appears to be higher than those reported in other locations. For comparison, rates of microplastics in sampled fish from the North Sea and in the North and Baltic Seas are 2.6% and 5.5% respectively, while those sampled from the Portuguese coast, the English Channel and the Balearic Islands in Spain are 19.8%, 37% and 68%. In the Turkish waters of the Mediterranean Sea, 41% of sampled fish contain microplastics in their digestive tracts.
This study is the first assessment of microplastic pollution in the Nile River, and only the second known study on plastic pollution in freshwater rivers in Africa. According to the researchers, the level of microplastic ingestion in the Nile River is ‘rarely found’ and that fish sampled from the river are ‘potentially among the most in danger of consuming microplastics on the planet’.
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The Sky team worked in collaboration with Dr Farhan Khan, who oversaw the research. Dr Khan’s team collected samples of two of the Nile River’s most common fish- the Nile tilapia and catfish- from Dahab Island in the centre of Cairo. These fish were purchased from local sellers, and their gastrointestinal tracts were dissected and examined for microplastics through isolating them in a strong alkaline solution.
An investigative team from Sky News spent two months travelling along the Nile, gathering visual evidence and testimony from farmers, fishermen, politicians and scientists, among others. They found the river extensively polluted all along the route ‘from its source in Lake Victoria to where it eventually empties into the Mediterranean Sea’.
The team says that some of the plastics found inside the fish guts could be seen by the naked eye. Dr Khan expressed concern that the density of plastic in the fish and the large percentage of fish affected had worrying implications on the future of all marine life in the Nile.
He says, “A collection of these types of fibres can really have an impact on how well a fish is able to find and digest its food, which could have a knock-on effect on, for example, feeding behaviour and nutrient uptake. This in turn could affect growth and reproduction and therefore the fish population itself.”
These microplastics act like bodies, which attracts toxic substances and which these toxics can bind to. This means there’s an increased danger that pollutants and pesticides which bind to the microplastics can also end up in the fish guts.
Dr Khan explains, “In most water systems, there’s a class of pollutants which includes pesticides which don’t mix well with water- so whenever they are in the water they are looking for materials to combine with and plastics provide that- so all these surfaces provide areas for contaminants to bind…what’s happening is the fish are feeding on plastics and they’re ingesting these plastics and these contaminants are making their way into the fish.”
While extensive research has been conducted on the presence of microplastics in the world’s oceans, there is a scarcity of their effects on the planet’s rivers, and almost none in Africa. This study bridges this gap and shines light on a problem not considered by many.
The study was conceived as part of the documentary, “The Plastic Nile,” produced by Sky News International. The research was carried out in secret labs in Egypt and the researchers asked to remain anonymous. In the past, Egyptian authorities have jailed those who have spoken in derogatory terms about the Nile or, in one case, questioned the cleanliness of the river. The Sky team applauded the researchers for their ‘considerable bravery, expertise and help’ in carrying out the study.
The Nile River is the longest river in the world at 6 693km, running through 11 countries in Africa. An estimated 250 million people rely on the river for food, water or tourism.
The team calls for more research into the effects of plastic pollution in freshwater rivers, and especially into the impact that contaminated fish are likely to have on those who depend on the river. They also urge for immediate action to mitigate microplastic pollution in the Nile River.
Featured image by: Sam valadi