Microplastics are now widely present in the drinking water of Lagos, the largest city in Nigeria, a newly published study finds.
In Nigeria, about 90 percent of the water available for drinking is sourced from boreholes or deep, narrow wells that tap into naturally occurring underground water.
The recent study in Environmental Toxicology and Chemistry, conducted by researchers from the China University of Petroleum and Covenant University in Nigeria, didn’t investigate the health effects of microplastics. But it was the first to look for them in boreholes in the Lagos area, finding they were “abundant” in the water and sediment in all of the boreholes they sampled.
These MPs — fragments of any type of plastic less than 5 mm in length — were found in borehole water and sediments at all 11 locations investigated on Lagos Island. Areas with high industrial activity had higher levels of MPs than areas with less industrial activity and lower population densities.
“The rate of degradation of these polymers is exceedingly low (depending on the environmental conditions and MP type), which will result in the increased accumulation of these MPs in the borehole drinking water with time,” the authors wrote.
“The risks associated with MPs are predominantly caused by the combination of these materials’ persistence and their potential accumulation in food chains,” they added.
The tiny particles and flakes, produced when plastic is disposed of improperly and breaks down, seep into the environment where they can be ingested by animals and humans. Recently, researchers detected microplastics in human blood for the first time.
Each year, the world produces upwards of 400 million tons of plastic waste, according to the United Nations. The World Health Organization issued a report in 2019 saying that microplastics were “ubiquitous,” but that not enough was known about what long-term exposure would mean for human health.
About 90% of the roughly 20 million residents of Lagos get their drinking water from boreholes, as they are considered less polluted than surface creeks and lagoons. This water is delivered untreated and commonly stored in tanks above people’s homes. The researchers noted that microplastics don’t degrade and if plastic pollution continues, it “will result in increased accumulation in the borehole drinking water with time.”
The authors finally, recommend that the government should police industrial sources of pollution more diligently. Researching microplastics in water is difficult, they note, because of the lack of a standard way to measure contamination. “It is essential to develop general criteria for sampling and reporting on microplastics” for further research, they conclude.