Microplastics Health Effects Workshop

Hosted by: SCCWRP, San Francisco Estuary Institute and University of Toronto

In coordination with the State of California Water Resources Control Board and the California Ocean Protection Council

Human and Ecological Health Effects of Microplastics in Water: Characterizing Current Knowledge and Identifying Research Priorities


In 2018, the California Legislature adopted a pair of bills that require the State to begin building microplastics management strategies for both drinking water and California’s coastal ocean and estuaries. Senate Bill 1422 requires the California State Water Resources Control Board to develop plans for measuring microplastic particles in drinking water by 2021. Senate Bill 1263 requires the California Ocean Protection Council to adopt and implement a statewide strategy for lessening the ecological risks of microplastics to coastal marine ecosystems.

SCCWRP is working with international experts in microplastics and environmental managers across the state to help provide a scientific foundation for these legislative mandates.

First, SCCWRP coordinated a microplastics measurement evaluation study intended to aid in management decision-making for selecting methods. This study was designed following a Microplastics Measurement Methods Workshop in spring 2019.

Second, SCCWRP is co-hosting a Microplastics Health Effects Workshop to bring together an international group of experts to identify the primary pathways by which microplastics affect biota, prioritize the microplastics characteristics (e.g., size, shape, polymer) that are of greatest biological concern, and identify critical thresholds for each at which those biological effects become pronounced. The first step in the health effects identification process involved a series of webinars, during which microplastics experts from around the world summarized current knowledge and discussed the latest findings regarding microplastics toxicity. Representatives from the State Water Resources Control Board and the Ocean Protection Council also shared their perspectives about how such science will be used in meeting the legislative mandates. This webinar series was open to the public, with the intent of informing the community (e.g., scientists, environmental managers, stakeholders) about the latest scientific developments regarding the potential health effects of microplastics. Video recordings of these webinars are available in the table below.

Workshop deliberations and report-out

Following the webinar series, microplastics experts deliberated about how to develop thresholds for when biological effects are likely to be triggered as a result of microplastics exposure. The experts investigated the feasibility of developing these thresholds for both drinking water and for organisms exposed in the ambient environment. The experts will summarize their findings during a two-hour, public webinar meeting on September 8, 2021 (8-10 a.m. Pacific Time). To attend the webinar, please register in advance.

DateEventSupporting Documents
September 8, 2021Report-out on findings of microplastics expert deliberationsWebinar agenda
PowerPoints for guest speakers
Background and Goals (Weisberg)
Dose Metrics and Particle Characteristics (Rochman)
Effects in Ambient Environment (Mehinto)
Effects in Drinking Water (Coffin)
Toxicity of Microplastics Explorer (Thornton Hampton)
Video recording of webinar
September 8, 2021 video recording
November 16, 2020Webinar: Moving ForwardPowerPoints for guest speakers
Effects across Biological Levels of Organization (Brander)
Anticipating and Adapting to Industry Changes (Galloway)
Video recording of webinar
November 16, 2020 video recording
November 9, 2020Webinar: Newest Research on Health EffectsPowerPoints for guest speakers
Uptake and Effects Following Ingestion (Stock)
Effects of Associated Chemicals (Wagner)
Effects in Lower Trophic Organisms (Cole)
Video recording of webinar
November 9, 2020 video recording
November 2, 2020Webinar: Taking on DiversityPowerPoints for guest speakers
Prioritizing Chemical Properties for Assessing Toxicity (Gouin)
Influence of Particle Chemistry on Uptake, Transport and Toxicity (Bouwmeester)
Probabilistic Assessment of Exposure, Effect and Risk (Koelmans)
Video recording of webinar
November 2, 2020 video recording
October 26, 2020Webinar: Summarizing Existing KnowledgePowerPoints for guest speakers
Introduction and Summary (Weisberg)
Drinking Water Modes of Impact (Wright)
Aquatic Ecosystem Modes of Impact (Rochman)
Risk Assessment (Koelmans)
Video recording of webinar
October 26, 2020 video recording
October 19, 2020Webinar: Management PerspectivesPowerPoints for guest speakers
Introduction (Weisberg)
State Water Board (Coffin)
California Ocean Protection Council (Gold)
Canada's Approach (Lemieux)
Video recording of webinar
October 19, 2020 video recording


For more information about this webinar series, contact Dr. Leah Thornton Hampton.