Researchers have called for further comprehensive studies following a World Health Organisation (WHO) report which concluded microplastics in drinking water posed no cause for concern.
Filtration systems used by water companies in the UK are sufficient to successfully filter out most plastics before drinking water reaches customers, the report said. However, it warned that the amount of plastic being returned to land from wastewater could pose an environmental risk.
Professor Peter Jarvis of Cranfield University, one of the writers on the WHO report, told Utility Week: “The transfer of plastics into waste is more of a problem. In water and wastewater treatment works the solid waste that is produced is often applied to soils as fertilizer. The concern is there could be plastics in this solid waste that is then returned to the land.”
He said the increasing public interest in reducing the use of single use plastics and in recycling should help reduce the amount of plastic that potentially ends up in wastewater.
The report from WHO, Microplastics In Drinking Water, said there is no reliable information suggesting there is a concern from chemicals and microbial pathogens associated with microplastics in drinking water.
He stressed more research is necessary to understand the longer-term impact of plastics in the water and how their structures will break down.
On the level of risk the microplastics pose to drinking water, Prof Jarvis said the data on the topic is “limited” but has been gaining momentum in recent years and further studies are being carried out now.
“Microplastics, in terms of types of particles being removed, are quite inert. We have a multi barrier approach to removal here in the UK. There are well operated treatment works that are optimised for treatment which efficiently remove microplastics from drinking water,” he said.
The report states monitoring of microplastics is not recommended currently because there is no associated evidence of a human health concern and stresses that microbial pathogens remain the most significant risk to human health from drinking water and the removal of these is of greater importance.
It also recommends further comprehensive research to understand the sources and occurrence of microplastics in fresh water and drinking-water. More evidence is also needed on the efficacy of different treatment processes and combinations of processes, and the significance of the potential return of microplastics to the environment from treatment waste streams including the application of sludge biosolids to agricultural land.