Regulatory Context

The United States does not currently have a single, comprehensive federal regulatory program establishing general environmental concentration limits for microplastics. Existing requirements are limited to particular products, media, or jurisdictions.

Relevant measures include:

• Federal Microbead-Free Waters Act of 2015: Prohibits the manufacture, packaging, and distribution of rinse-off cosmetics containing intentionally added plastic microbeads. It also applies to rinse-off products that are both cosmetics and nonprescription drugs, such as certain toothpastes. The law does not broadly regulate all microplastics or secondary particles produced by the breakdown or abrasion of larger plastic materials.

• California Health and Safety Code § 116376: Directed the State Water Resources Control Board to define microplastics in drinking water and establish standardized testing, reporting, and public-disclosure procedures. The resulting policy establishes a monitoring framework; it does not establish a numeric drinking-water limit for microplastics.

• California Safer Consumer Products Regulations: California finalized a rule adding microplastics to its Candidate Chemicals List, with an effective date of October 1, 2026. The listing allows the state to evaluate products that contain or generate microplastics. The listing alone does not impose new obligations on manufacturers or retailers; product-specific requirements would require a separate Priority Product rulemaking.

• California SB 54: The state’s packaging EPR law is also relevant to plastic-pollution prevention because it establishes requirements and statewide goals for reducing and managing covered packaging and plastic food-service ware. It does not establish general environmental concentration limits for microplastics.

Source and Pathway Evaluation

Microplastics may be intentionally produced at a small size or generated when larger plastic materials fragment or experience abrasion. Potential sources include plastic packaging, synthetic textiles, tires, coatings, consumer products, industrial materials, wastewater, stormwater, and improperly managed waste.

An evaluation may consider:

• Potential primary and secondary sources

• Facility operations and material use

• Wastewater, stormwater, atmospheric, and surface-water pathways

• Transport through water, sediment, soil, or air

• Particle size, shape, density, and polymer composition

• Potential environmental receptors

• Available background and regional information

• Gaps and limitations in the existing data

Identification of a potential source does not, by itself, establish the amount released, environmental exposure, or responsibility for observed conditions.

Sampling and Data Review

Microplastics sampling and analysis remain technically challenging. Results can be affected by the sampled medium, particle-size range, collection method, laboratory procedure, contamination controls, and reporting units.

Technical support may include:

• Review of sampling and analysis plans

• Evaluation of sampling locations and environmental media

• Review of quality-assurance and contamination-control procedures

• Assessment of laboratory methods and reporting limits

• Validation and interpretation of analytical results

• Comparison of results among locations or sampling events

• Identification of data gaps and uncertainty

• Independent review of monitoring reports

Results should be interpreted in the context of the methods used. Data produced using different collection, preparation, or analytical procedures may not be directly comparable.

Impact and Risk Evaluation

Microplastics are a diverse category of particles rather than a single substance. Their characteristics and potential effects can vary by polymer, particle size, shape, concentration, additives, associated chemicals, and exposure pathway.

Evaluations may include:

• Review of potential human and ecological exposure pathways

• Assessment of relevant environmental and toxicological literature

• Review of effects on aquatic or sediment environments

• Evaluation of additives or chemicals associated with particles

• Identification of sensitive populations or environmental resources

• Distinction between measured conditions and potential exposure

• Documentation of scientific uncertainty and study limitations

• Independent review of risk or impact assessments

The detection of microplastics does not, on its own, establish a specific health effect or ecological impact. Conclusions should reflect the quality of the evidence and the limitations of available methods and research.

Monitoring and Management

Where potential sources or pathways are identified, possible measures may include:

• Source reduction

• Material substitution

• Product or packaging redesign

• Stormwater or wastewater controls

• Filtration or separation systems

• Capture of larger plastic debris before fragmentation

• Operational controls

• Environmental monitoring

• Evaluation of treatment or mitigation performance

The suitability and effectiveness of any measure depend on site conditions, particle characteristics, affected media, regulatory requirements, and the quality of the available evidence.

Community and Agency Support

Microplastics information can be difficult to interpret because terminology, methods, and regulatory programs continue to evolve. ACHIEVE ENVIRONMENTAL can support:

• Plain-language summaries of scientific and regulatory information

• Review of proposed monitoring programs

• Independent interpretation of reported results

• Documentation of community questions and observations

• Public meetings and technical presentations

• Review of agency or applicant-prepared studies

• Development of transparent monitoring and reporting measures

• Tracking of relevant regulatory developments

Talk to Us About Microplastics

Evaluating a potential source, a monitoring program, or new regulatory requirements? Contact us to talk through your project.