Even the rural headwaters of the south branch of the Raritan River contain microplastics, particles so small as to be nearly invisible, according to pilot study by a watershed watchdog.
The newly released study by the Raritan Headwaters Association found higher concentrations downstream of major wastewater treatment plants based on sampling at 10 sites along a 23-mile stretch of the river between Clinton and Branchburg.
“One thing that was very striking was that every single sample we took had microplastics in it,’’ said Kristi MacDonald, science director of the Bedminster-based nonprofit and author of the study.
How microplastics are formed
Microplastics are created by either the breakdown of larger plastic items, such as water bottles, plastic bags, food wrappers, and fishing line or the manufacture of small beads added to facial products, toothpaste, and cleaning products. They also include fibers from clothing.
The results of the study, conducted in 2017, are sure to amplify concerns about plastic pollution in water, a widespread problem that poses a risk to freshwater marine life and drinking water. The Raritan River Basin provides drinking water to 1.5 million people in New Jersey.
The study found that microplastic concentrations were higher just downstream of three of four wastewater-treatment plants along the stretch of the river.
Multiple sources of pollution
“It indicates that water users on the sewer line, including households, businesses, schools, and others, may take individual measures to decrease microplastics in wastewater,’’ MacDonald said, adding the study is just the first step.
“It’s not just coming from wastewater plants,’’ she said. Other studies have found a variety of other nonpoint sources, such as discarded plastic litter and plastic blown from landfills and other plastic debris.
“Right now, it’s very hard to get away from it,’’ MacDonald said. “Everything is wrapped in plastic.’’
The pilot study highlights the need to reduce single-use plastic bags, one of the leading causes of plastic pollution. The Legislature is considering a ban on single-use plastic bags, as well as plastic straws and foam cups and containers, but the issue has yet to win final approval. About a dozen New Jersey municipalities also have banned single-use plastic bags.
In an annual stream cleanup conducted by the association, volunteers removed 13.5 tons of trash from the river and stream banks within the watershed, including 7,643 plastic bottles and 2,688 plastic bags.
“Our annual stream cleanup prevented these plastic bottles and bags from eventually becoming microplastics,’’ she said.