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Other Monitoring Programs & Studies (e.g., Fish Tissue, Microplastics, Metals) - Microplastics
New! DRBC Publishes Microplastics Report

View Report

Reducing Microplastics in the Delaware River Estuary (pdf; August 2022)

View Study Results (click to view)

Image showing microplastics study locations and link to data. Graphic by the DRBC.
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View News Release

Microplastics pervasive in waters adjacent to Delaware River’s population centers (issued August 30, 2022)


More Information

DRBC's Microplastics Study

What are Microplastics?

Plastic is perhaps the most prevalent and persistent type of debris found in our oceans, rivers and large lakes.

Definition of Microplastics

Plastic pollution is found in all shapes and sizes, but plastic debris less than five millimeters in length (or about the size of a sesame seed) is known as "microplastics."

These tiny particles easily pass through water filtration systems and end up in receiving waters.

How microplastics impact human health and aquatic life is still unknown.

Sources of Microplastics

Over time, larger plastics degrade into microplastics, but microplastics also include originally manufactured products such as the following:

• Microbeads, found in cosmetics and personal care products (such as toothpaste);

• Industrial scrubbers used for abrasive blast cleaning;

• Microfibers, generated from washing synthetic clothing made of polyester and nylon; and

• Resin pellets used in the plastic manufacturing process.

DRBC Microplastics Study
Map of DRBC Microplastics Study Sites. Map by DRBC.
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In 2018, the DRBC received a grant from the Delaware Watershed Conservation Fund to monitor for microplastics and model loadings of microplastics in the upper Delaware River Estuary from Trenton, N.J. to the C & D Canal.

Samples were collected in spring and fall 2019, with additional samples collected in 2020 and 2021.

Other sections of the Delaware River have been studied, but not this highly urbanized section, which is likely a major contributor to microplastics found in the estuary and bay.

Study Goals

• To better understand the nature and distrubution of microplastics in this portion of the Delaware River Estuary.

• To increase public awareness of microplastics and support cleanups to reduce plastics loadings.

This study will lay the groundwork for future microplastics monitoring and cleanup efforts in the Basin and beyond.

Sites Sampled: 15

• Four Delaware River Estuary sites (one site in each DRBC Water Quality Zone 2-5)

• Ten tidal Delaware River tributaries: Four in Pa., four in N.J. & two in Del.

• Delaware River at Trenton, N.J. (captured the largest loading to the estuary, the non-tidal Delaware River)

Sampling Methods & Analysis

Samples were collected via net, grab sample or Niskin sampler.

  • Net samples were collected on six tributaries.

  • Grab samples were collected by bridge on nine tributaries (not the Cooper River) and the Delaware River at Trenton.

  • A Niskin sampler was used to collect samples from the Delaware River Estuary by boat.

Samples were analyzed by Temple University for microplastic concentrations.

  • To determine concentrations, samples were filtered and sediment and organic matter removed.

  • Microplastics found in the samples are then analyzed using Fourier transform infrared spectroscopy. 

  • Shape, color, size and composition of the microplastics found were determined.

Images of various shapes of microplastic particles found in DRBC samples. Image by the DRBC.
Images of various shapes of microplastic particles found in DRBC samples


Modeling Microplastics

  • DRBC used its exisitng 3D Hydrodynamic Model to look at how microplastics are transported in the Delaware River Estuary: where microplastics could travel to and concentrations from key tributary sources.

  • Simulated low & high flow conditions. Higher flows corresponded to faster travel times and a larger footprint.


Study Results

  • Microplastics were found in each sample, including blanks.

  • Most common: polyester, rayon & cellulosic fibers. A variety of shapes, colors, sizes and types were seen.

  • Grab samples showed higher concentrations than net samples; potential reason is that smaller particles could get through net.


Study Final Report & Data Mapper: August 2022

Presentations Given

Cleaning Up Plastic Pollution

In 2021, two cleanups were organized by DRBC staff in known plastic-pollution hotspots.

  • Cleaning up large plastic debris prevents fish and wildlife from becoming entangled in objects like cords, fishing line, nets and beverage containers.

  • On a finer scale, removing these debris before they have a chance to break down will reduce the presence of microplastics and lower the risk of other harmful chemicals entering the Basin’s waters.

  • Better understanding which source tributaries are introducing the most microplastics will help target future cleanup efforts.


Study Photos

Plastic pollution along Philadelphia's Frankford Creek. This is one of the monitoring sites in DRBC's study. Photo by DRBC. DRBC staff collect a water sample from the Delaware Estuary to monitor for microplastics. Photo by DRBC.
Plastic pollution along Philadelphia's Frankford Creek. This is one of the tributary monitoring sites in DRBC's study. Photo by the DRBC. DRBC staff use a Niskin sampler to collect a water sample from the Delaware Estuary to monitor for microplastics. Photo by the DRBC. 
DRBC staff collects a sample to monitor microplastics ocncentrations from the Assunpink Creek. Photo by DRBC. DRBC staff collects a sample from the Neshaminy Creek to monitor for microplastics. Photo by DRBC. DRBC staff collects a flow measurement from the Neshaminy Creek during a sampling event for microplastics. Photo  by DRBC.
DRBC staff uses a net to collect a sample from the Assunpink Creek to monitor for microplastics. Photo by the DRBC. DRBC staff collects a grab sample from the Neshaminy Creek to monitor for microplastics. Photo by the DRBC. DRBC staff measures flow and uses a net to collect a sample from the Neshaminy Creek to monitor for microplastics. Photo by the DRBC.
Other Microplastics Studies in the DRB
Microplastics as seen under the microscope by University of Delaware researchers. Photo courtesy of the Univ. of Delaware. 
As seen under the microscope: microplastics collected from the Delaware Bay by University of Delaware researchers. Photo courtesy of the University of Delaware. 

University of Delaware

United States Geological Survey and the National Park Service

     • View Study Fact Sheet

The Philadelphia Water Department

Rutgers University

U.S. EPA

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