With no solution in sight, the sizes of microplastics from a highly urbanized estuarine and coastal system with numerous sources of fresh water, including the Hudson River and Raritan River remain a cause to worry about plastic pollution in sea water.

In their study, Rutgers University researchers found tiny pieces of plastic in the Hudson-Raritan Estuary in New Jersey and New York indicating that stormwater could be an important source of the plastic pollution that plagues oceans, bays, rivers and other waters and threatens aquatic and other life.

plastic pollution
Plastic pollution on a beachNOAA

"Stormwater, an understudied pathway for microplastics to enter waterways, had similar or higher concentrations of plastics compared with effluent from wastewater sewage treatment plants," said senior author Nicole Fahrenfeld of Rutgers University-New Brunswick. "More research is needed to increase understanding of the full impact of microplastics on ecosystems."

Ever since the early 1900s, when General Bakelite began manufacturing Bakelite, the first synthetic plastic on Earth, in New Jersey, plastics are used in myriad products worldwide and now affecting marine and other environments, posing risks to wildlife and aquatic life. Possible sources of microplastics include municipal, industrial and stormwater outfalls.

Study on plastic residue

The Rutgers team collected water samples during a dry period in July 2018 and after a heavy rainfall in April 2019 from wastewater entering treatment plants, wastewater discharges and stormwater.

They found highest levels of microplastics, ranging from two-hundredths of an inch to less than a tenth of an inch long, at the mouth of the Raritan River. The sudy published in the journal Chemosphere shows higher concentrations of smaller microplastics in Raritan Bay and the Atlantic Ocean off New Jersey likely came from the Hudson River. 

"The smaller microplastics likely spent more time in the turbulent Hudson River, leading to increased aging and breakdown of plastics," said Fahrenfeld. Polyethylene, widely used in bottles, trash bags and other items, was the most common plastic found in the Raritan River and Hudson-Raritan Estuary.

A 2017 Rutgers-led study found high levels of microplastics in the Raritan and Passaic rivers, where scientists identified more than 300 organic chemical compounds used in microplastic particles.