NJ Clean Stream
njcleanstream.org
Where NJ’s microplastics come from — and which sources are hardest to control
Microplastic contamination of drinking water is not like other drinking water contaminants. It does not have a single industrial source that can be regulated, a single pathway that can be intercepted, or a single responsible party who can be compelled to remediate. Understanding where New Jersey’s microplastics come from — and which sources can actually be controlled — is the foundation for a realistic reduction strategy.
Tire rubber wear particles: the largest and most intractable source
Tire rubber wear particles (TRWP) are produced by the abrasion of tires against road surfaces during normal driving. New Jersey, with one of the highest vehicle densities and vehicle miles traveled per square mile in the country, generates extraordinary quantities of tire rubber particles washing off road surfaces into storm drains and waterways.
Tire rubber is not pure rubber. Modern tires are complex composites containing natural rubber, synthetic rubber polymers (primarily styrene-butadiene rubber), carbon black, zinc oxide, sulfur, and chemical additives including polycyclic aromatic hydrocarbons (PAHs) and benzothiazole that are toxic to aquatic organisms. Research has identified 6PPD-quinone — a transformation product of a tire rubber antioxidant — as the probable cause of coho salmon die-offs in Pacific Northwest urban streams, demonstrating that tire rubber particles carry chemical toxicants that can devastate aquatic ecosystems.
Control potential: partial. Road drainage bioswales and green infrastructure can capture tire rubber particles before they reach water bodies. “Green tire” development with reduced wear rates and lower-toxicity formulations is an active area of research. Reducing vehicle miles traveled through transit investment and land use reform is the most direct approach but least likely to achieve dramatic near-term results given NJ’s car-dependent development patterns. Regulatory pressure on tire manufacturers to eliminate the most toxic chemical additives is an achievable near-term policy goal.
Synthetic textile fibers: pervasive, small, and difficult to capture
A single wash load of synthetic textiles can release anywhere from tens of thousands to several million fibers that pass through washing machine effluent into the wastewater system. Treatment plants capture a significant fraction — studies suggest 65 to 99 percent removal — but the fraction passing through in treated effluent, discharged continuously to receiving waters, represents a very large absolute number of fibers per day. Synthetic textile fibers are among the most commonly detected microplastic types in drinking water studies, and their fiber geometry — long and thin — makes them particularly challenging to remove in water treatment.
Washing machine filters. Installing filters on washing machine outlet hoses can achieve 60–90 percent fiber removal at the source. France enacted a requirement in 2023 that all new washing machines include built-in fiber filters. NJ Clean Stream is advocating for a similar requirement in New Jersey.
Wastewater treatment optimization. Upgrading treatment plants to include membrane filtration can achieve higher fiber removal. The cost is substantial but the water quality benefit extends beyond microplastics.
Textile industry design. Fabrics engineered to minimize shedding through tighter weave structures or alternative fiber formulations can reduce fiber release at the source.
Single-use plastics and plastic litter
Single-use plastics found on roadsides, in parks, on beaches, and in urban waterways contribute microplastics through fragmentation: plastic litter exposed to UV radiation, temperature cycling, and mechanical abrasion fragments progressively into smaller particles transported by wind and water into aquatic environments. New Jersey’s beaches are among the most plastic-littered in the northeastern United States.
Control potential: substantial. Extended producer responsibility legislation requiring plastic product manufacturers to fund collection and recycling. New Jersey enacted a bag ban in 2022 — one of the more aggressive state frameworks for single-use plastic reduction. Deposit-return systems for beverage containers (bottle bills) significantly reduce litter rates; expanding NJ’s existing bottle bill to cover water bottles and non-carbonated beverages would address one of the most prevalent single-use plastic litter categories.
Agricultural plastics: the hidden source in South Jersey
Plastic mulch films, irrigation drip tape, greenhouse covers, and other agricultural plastics are used extensively in New Jersey’s agricultural sector, concentrated in Burlington, Ocean, Atlantic, Cumberland, Salem, and Gloucester counties. These materials degrade in field conditions — mulch films are particularly problematic, fragmenting during removal and leaving plastic residues in agricultural soils that persist indefinitely and can reach the Coastal Plain aquifer system underlying much of South Jersey.
Control potential: moderate. Biodegradable plastic mulch films are available but more expensive and often slower to biodegrade under real field conditions than claimed. Plastic retrieval programs, financial incentives for plastic-free agricultural practices, and extension services that promote reduced plastic use are elements of an agricultural plastic reduction strategy. Certification and labeling standards for biodegradable agricultural plastics would help farmers make informed choices.
Atmospheric deposition: the global pathway
Studies conducted in remote locations — the French Pyrenees, the Arctic, the middle of the Pacific Ocean — have found microplastic deposition rates explainable only by long-range atmospheric transport from population centers hundreds or thousands of miles away. In New Jersey, atmospheric deposition represents an input to water bodies, soils, and open reservoirs that cannot be fully addressed through local source control. It is the background level of contamination that reflects the global nature of the plastic problem. Understanding its magnitude through systematic monitoring is important for contextualizing the potential impact of local source control measures.
Wastewater treatment plant effluent: the concentrated discharge pathway
New Jersey’s major wastewater treatment plants — the Passaic Valley Sewerage Commission, the North Hudson Sewerage Authority, the Middlesex County Utilities Authority, and dozens of other regional facilities — collectively treat billions of gallons of wastewater per year. Even at high microplastic removal efficiencies, the total microplastic load discharged in treated effluent is very large. Where treatment plant discharge reaches surface water bodies that serve as drinking water sources — as is the case for several New Jersey water intakes on the Passaic, Raritan, and Delaware rivers — the effluent microplastic load contributes directly to source water microplastic concentrations.
Control potential: high with investment. Advanced tertiary treatment — membrane bioreactors, ultrafiltration, or other membrane-based separation technologies — can achieve very high microplastic removal rates from wastewater. Cost is substantial but provides broad water quality benefits beyond microplastics, including nutrient removal and pathogen reduction. NJ Clean Stream supports investment in advanced wastewater treatment as part of a comprehensive microplastic source control strategy.
A source control prioritization framework
- Highest priority — achievable with existing policy tools: Synthetic textile fiber filters on new washing machines (legislative requirement); bottle bill expansion to non-carbonated beverages; enhanced stormwater management targeting tire rubber particle capture; agricultural plastic retrieval and biodegradable plastic transition programs.
- Medium priority — achievable with investment and regulatory change: Advanced tertiary treatment at major wastewater treatment plants discharging to drinking water source waters; tire rubber chemical additive restrictions targeting most toxic components; extended producer responsibility for single-use plastics.
- Long-term systemic: Reduction in vehicle miles traveled through transit investment and land use reform; transition from synthetic to natural fiber textiles; comprehensive reduction in single-use plastic production and use.
This is Article 2 of 3. Article 1 introduces microplastics, their health implications, and the regulatory gap. Article 3 explores what water treatment plants can and cannot filter out — and what NJ should require of utilities now.