PFAS, Microplastics & Contaminants: Unseen Threats to the Sea

Marine ecosystems worldwide are increasingly challenged by anthropogenic, or human-derived, pollutants. Among the most concerning are per- and polyfluoroalkyl substances (PFAS) and microplastics, two contaminant classes that are ubiquitous across freshwater, estuarine, and marine systems, shaping the chemistry of aquatic ecosystems. Unlike traditional pollutants, these contaminants are persistent, capable of traveling long distances, and known to accumulate within trophic networks. Their impacts not only pose ecological threats but also present public health concerns, since humans and marine life share environments and food sources.

PFAS and Microplastics: Persistent and Pervasive

PFAS, often called “forever chemicals,” are synthetic compounds used in firefighting foams, nonstick cookware, textiles, and countless consumer products. Their chemical structure makes them highly resistant to natural degradation processes. Once released, PFAS accumulate in soils, waterways, and marine systems, where they bind to proteins and persist in living tissue for years.

Microplastics, defined as plastic fragments smaller than 5 millimeters, originate from the breakdown of larger plastic debris or from direct sources such as microbeads in personal care products and synthetic fibers from clothing. Because of their small size, microplastics are ingested by organisms across all trophic levels, from plankton to dolphins and whales. These particles often carry chemical additives or adsorb other pollutants, acting as vectors for contaminant exposure.

Together, PFAS and microplastics are considered “emerging contaminants of concern” because of their ubiquity, persistence, and complex biological effects.

Impacts of PFAS and Microplastics on Oceans and Estuaries

The effects of PFAS and microplastics are not limited to a single species group; they permeate entire ecosystems. Studies have documented impacts ranging from physiological stress in fish and invertebrates to population-level health concerns in marine mammals.

These effects threaten not only individual animals but also the stability of entire populations, particularly for long-lived, slow-reproducing species such as whales and dolphins.

Dolphins and Other Marine Mammals as Sentinels

Marine mammals are considered sentinel species because their health reflects the condition of the ecosystems they inhabit. Bottlenose dolphins (Tursiops truncatus), for example, have been the focus of long-term research in multiple regions of the US. Populations in the Indian River Lagoon (IRL), Florida, and Charleston Harbor, South Carolina, have all provided critical insights into contaminant exposure. Findings consistently show that dolphins accumulate high levels of persistent pollutants, including PFAS, PCBs, and heavy metals, and that these exposures correlate with increased disease prevalence, immune suppression, and reproductive challenges.

Other marine mammals, such as harbor seals in Puget Sound and polar bears in the Arctic, have also revealed the far-reaching nature of these pollutants, demonstrating that even remote environments are not immune to industrial and consumer chemical impacts.

Case Study: Florida’s Indian River Lagoon

The IRL along Florida’s east coast is one of the most biodiverse estuaries in North America and serves as a valuable case study for understanding contaminant impacts. This ecosystem supports more than 4,000 species of plants and animals, including a resident population of bottlenose dolphins that has been extensively studied, with the population subject to four unusual mortality events (UMEs) between 2002 and 2020.

Research in the IRL has documented elevated levels of PFAS, mercury, and microplastics in water, sediments, and wildlife. Dolphins in the lagoon carry contaminant burdens higher than many other US populations, and these exposures have been linked to immune system alterations, higher rates of infectious disease, and impaired reproductive success.

The IRL illustrates how a combination of urban runoff, wastewater discharge, and historical industrial activity can create a “perfect storm” of environmental pressures. Because dolphins and other marine mammals share coastal waters with human populations, their health challenges also raise concerns for public health. Seafood harvested from contaminated ecosystems may serve as another pathway for human exposure to PFAS, mercury, and microplastics.

Partner with APTIM to Protect Marine and Human Health

The persistence of PFAS, mercury, and microplastics underscores the deep connection between marine ecosystems and human health. Contaminants released on land, through industrial activities, consumer products, and wastewater, eventually reach rivers, estuaries, and oceans, where they accumulate in organisms and move through trophic networks. Understanding these pathways is critical for mitigating risks to both marine life and human communities.

Sustainable choices matter at every level. Reducing single-use plastics, supporting innovations in green chemistry, upgrading wastewater treatment infrastructure, and strengthening regulatory frameworks all help reduce contaminant inputs. On an individual level, consumers can support companies that prioritize sustainable materials, minimize unnecessary plastic use, and advocate for stronger environmental protections.

APTIM works alongside government, industrial, and commercial clients to address the challenges of emerging contaminants. Through data-driven environmental consulting, innovative remediation solutions, and comprehensive monitoring programs, APTIM supports organizations as they work to reduce the impact of PFAS and other pollutants on both human and ecological health.

Protecting marine ecosystems is not just about safeguarding wildlife, it’s about ensuring the resilience of our coastal communities, preserving biodiversity, and securing safe and sustainable food sources. By taking proactive, science-informed action, we can collectively reduce the threats of PFAS and microplastics and ensure a healthier future for people and marine life alike.

Discover how APTIM’s environmental consulting and PFAS solutions can help your organization reduce contaminant risks and support healthier oceans and thriving communities.

Published October 2025