Microplastics are in NJ’s drinking water — and we’re only beginning to understand what that means

Published by NJ Clean Stream  |  Microplastics in NJ Drinking Water Series, Article 1 of 3

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What are microplastics?

Primary microplastics are particles manufactured at small size for specific applications — microbeads in personal care products (federally banned in rinse-off cosmetics since 2015), plastic pellets that are the industrial feedstock for all plastic manufacturing, and fibers shed by synthetic textiles (polyester, nylon, acrylic) during washing.

Secondary microplastics are fragments produced by the physical and chemical weathering of larger plastic items — single-use plastics, packaging, agricultural films — that fragment over time through UV radiation, mechanical abrasion, and weathering into progressively smaller pieces.

Nanoplastics are particles smaller than one micrometer — one-thousandth of a millimeter. They are the most concerning size fraction because their extremely small size allows them to cross biological barriers — cell membranes, the blood-brain barrier, the placental barrier — that exclude larger particles. The study of nanoplastics is still emerging, limited by the difficulty of detecting particles at this scale.

Where microplastics come from in New Jersey

Tire rubber wear particles are the single largest documented source of microplastics in urban stormwater runoff. New Jersey, with one of the highest vehicle densities and vehicle miles traveled per square mile in the country, generates enormous quantities of tire rubber particles washing off road surfaces into storm drains, streams, and water bodies continuously.

Synthetic textile fibers shed from polyester, nylon, and acrylic clothing and furnishings during washing. A single load of laundry with synthetic textiles can shed hundreds of thousands of plastic fibers that pass through washing machine effluent into the wastewater system and ultimately into receiving waters.

Single-use plastics and litter fragment over time through UV radiation and mechanical abrasion. New Jersey’s beaches are among the most plastic-littered in the northeastern United States.

Wastewater treatment plant effluent represents a concentrated, continuous pathway for microplastic discharge. Even at 95–99 percent removal efficiency, the residual discharged from New Jersey’s numerous major treatment plants into rivers and estuaries is a very large absolute number of particles per day.

Atmospheric deposition — the fallout of airborne plastic particles — deposits microplastics into water bodies, soils, and open reservoirs. Studies have found atmospheric microplastic deposition even in remote locations like the French Pyrenees and the Arctic, demonstrating this is a global phenomenon that cannot be fully addressed by local source control.

What the health science says

What the scientific uncertainty means for policy

The genuine scientific uncertainty has been used to argue that regulation is premature. NJ Clean Stream rejects this argument. The uncertainty is about the magnitude of harm and the dose-response relationship — not about whether harm occurs at all. The precedent of PFAS is directly relevant: the argument that regulation should await definitive proof resulted in decades of additional exposure while the science accumulated. Some regulatory responses — monitoring, source reduction — are achievable without resolving the scientific uncertainty and are justified on grounds that extend beyond microplastics alone.

Where New Jersey stands on microplastics regulation

The federal EPA has not established an MCL for microplastics. New Jersey has not established a state standard. No monitoring requirement exists under current federal or state regulations. This regulatory void exists despite growing scientific literature, documented presence of microplastics in drinking water systems nationwide, and the first human health outcome data linking microplastic body burden to cardiovascular disease.