Plastic pollution is a serious environmental menace. A recent United Nations Environment Programme report indicates that there could be more individual plastic items than fish in the oceans by 2050.
People continue to find ways of using plastic because it is easily shaped and lasts a long time. The world's plastic production currently stands at about 380 million tonnes a year. That also means there has been a surge in plastic pollution.
Nigeria, whose population has been predicted to be the third largest in the world by 2050, uses 0.85 million metric tonnes a year and in 2010 accounted for 2.67% of the world's mismanaged plastic waste.
Environmental researchers are finding that pollution produced in one environment finds its way to others via rivers and oceans. It also finds its way into food chains, including food that people eat. Plastics greater than 5mm in size - macroplastics - are often broken down into smaller pieces - microplastics. This often happens through ingestion and digestion by animals.
In the first study of its kind, my research group investigated microplastic pollution in the Osun River system in Nigeria. We did this by testing for microplastics in gastropods, commonly known as snails. We found fibre was the most common microplastic in the species. This is the first chemical identification of polymer types in African freshwater invertebrates.
To provide a comparison we also researched microplastics in a gastropod species in the Rhine River, an international river with economic importance.
Our findings revealed the presence of microplastics in both rivers, with higher microplastic load per individual in the African gastropods. Polyethylene, nylon and polypropylene plastic types, which are commonly being used as shopping bags and bottle caps, were recorded in the study.
Our findings provide insights into the differences between a developed nation that has good waste management practices and a developing nation with poor waste management practices.
Plastic waste in Nigeria
Plastic waste is a common sight in Nigeria, on the land and in freshwater and coastal environments. Lots of it is generated in along the coast through activities like fishing, shipping and recreation. But research has also established a link between plastic waste generated inland and that found in the ocean.
In Nigeria, most plastic waste introduced into the environment through human activities inland. It is washed off into streams and rivers when rain falls, and ultimately transported to the ocean.
My research group reported that rivers could serve as either the sink (final destination) or the conveyor belt (mode of transfer) of plastics to the ocean.
My research group also investigated the presence of microplastics in two rivers that drain into the Atlantic Ocean - the Osun and Ogun Rivers. We used some freshwater insects as bioindicators. We found that the animals had ingested microplastics in the form of fibres and fragments. Among the plastic types were polyester and polypropylene.
The harm plastic waste can cause
Plastic pollution in Nigeria spells a great danger to Nigerians, animal species and the environment.
Research has found that they can have serious physiological and toxicological effects when they're ingested by animals, even threatening certain species.
More worrisome is the fact that such plastics can be transferred along the food chain from animals to man, posing the same toxicological risk.
Another implication of plastic pollution in Nigeria is its potential to reduce the aesthetic values of landscapes, beaches and shorelines, making them become less attractive for activities, like tourism. Some environmental psychologists have also associated clean and attractive environments with human health.
But Nigeria is doing very little to contain the threat from plastics.
The growing trend of plastic pollution in Nigeria, and the danger it poses to the environment and human health, calls for urgent action. Many countries have either formulated or reviewed their policies on the use of plastics. But Nigeria has been slow to respond.
Earlier this year the legislative arm of government passed a bill to ban plastic bags.
Nigeria was late to the party. Other African nations like Kenya, Uganda and Rwanda have banned plastic bags and formulated policies aimed at checking plastic pollution in their respective environments. To a large extent, these bans have achieved positive results.
Nigeria needs to quickly formulate a strong policy on plastics and plastic pollution, and then put it into action. But implementation needs attention so that it achieves its objectives.
Other steps government could take could include organising awareness campaigns to encourage individuals to reduce, reuse and recycle plastic. It could also consider banning disposable single-use plastics like straws, cutlery and plates.
Nigeria has a history of taking action, but then not pushing through to ensure the right outcomes are reached. For example, 10 years ago, the country spent hundreds of millions of naira on plastic waste recycling plants in 26 cities. Today, these facilities don't work.
It can't afford to waste more time.