Microplastics: Deadly and widespread environmental pollutants

UC Riverside researchers are pioneering a new approach to investigate the elusive subject of microplastics in Los Angeles County’s urban waterways. With an increased focus on understanding the quantity, quality, and origins of these tiny pollutants, the team aims to shed light on their potential impacts on both the environment and human health.

Microplastics are defined as particles no larger than five millimeters in diameter, roughly the size of a pencil eraser. Within this category, nanoplastics are even smaller, with dimensions far smaller than the width of a human hair. Although scientists have been aware of these particles’ presence in the environment for decades, concerns surrounding their potential effects have only recently gained momentum.

“There is mounting evidence that these materials are toxic,” explained Professor Andrew Gray. Recent studies have shown that microplastics can negatively affect reproductive health, particularly in males. 

How microplastics harm humans and ecosystems

Furthermore, small microplastics and nanoplastics have the ability to cross organ boundaries and infiltrate cell walls, potentially carrying other harmful compounds with them. These include heavy metals or PFOS (per- and polyfluoroalkyl substances), which are used in products like fire-fighting foams, stain-resistant fabrics, and food packaging.

Microplastics also pose threats to animals, as they can inadvertently consume the particles, leading to blockages in their airways and digestive tracts.

In an effort to better manage these pollutants in our water systems, scientists must first identify the types of plastics present and determine their sources. Gray’s research group at UCR has been granted nearly $1 million from Los Angeles County’s Safe Clean Water Program to uncover this critical information.

“Microplastics are a complex suite of contaminants with a wide range of particle sizes and shapes, and different ramifications for aquatic and human health,” Gray said.

The research team aims to establish a baseline understanding of the microplastics present in the waterways and gain insights into how they arrived there, their discharge points, and their transportation routes through urban water systems. Gray added, “We expect that stormwater moves most of the microplastics through rivers and streams and into the coastal ocean.”

How the study will work

The study will investigate the lower Los Angeles River, lower San Gabriel River, Ballona Creek, and the Dominguez Channel. Collaborating with LA County Public Works, the research team will collect stormwater samples from pre-established monitoring stations, which will then be analyzed in the laboratory of Professor Gray.

The primary goal of Gray’s group is to use the data gathered from these four waterways to standardize the monitoring methods for microplastics in streamflow, particularly during storm conditions. 

Additionally, the researchers aim to develop models of how plastics move through waterways, applying these models to guide monitoring efforts in other streams where stations do not yet exist, and where establishing them would be costly.

Enhanced monitoring systems have the potential to inform a range of management strategies targeted at specific compounds. For instance, Gray’s laboratory has frequently identified one type of plastic in water samples that originates from tires and streets.

“We tend to think about emissions from combustion, but there are a lot of non-combustion vehicle-related emissions as well. Brakes, fluids, tires, and roads – all these things contain plastics that leach out, break down, and get washed into our waterways,” explained Professor Gray. “Tires used to be relatively simple concoctions, but that is no longer the case. Today’s tires are mixed with a lot of petroleum-based plastics and additives.”

Tire and road particles can have toxic effects on various commercial fish species, including salmon and trout, as well as other aquatic animals. By pinpointing the entry points of these pollutants into waterways, researchers can devise strategies to reduce runoff and clean the water before it enters municipal drains and flows downstream.

Strategies to reduce levels of microplastics

There are numerous everyday strategies that consumers can adopt to decrease plastic waste, such as choosing reusable containers and items over single-use plastics. Gray also envisions a future where more pressure is applied to sectors of the economy that manufacture plastic goods.

As microplastics are often formed by the breakdown of larger plastic particles already present in the environment, the problem is likely to persist. “Even if we stop producing all plastics today, the legacy of pollution will go on for decades. But not all microplastics may be toxic, and for those that are, we have the opportunity to decrease their manufacture and impact,” Gray said. “Improved monitoring will definitely help guide those efforts.”

By unraveling the complexities of microplastic contamination, the UCR researchers hope to develop effective strategies for mitigating the potential risks they pose to both the environment and human health. This groundbreaking work will undoubtedly contribute to a more comprehensive understanding of the consequences of microplastic pollution and inform future policy decisions to address this growing concern.

More about microplastics

Microplastics are small plastic particles typically measuring less than 5 millimeters in diameter. They can originate from a variety of sources, such as the breakdown of larger plastic materials or the direct release of small plastic particles like microbeads found in personal care products. Microplastics can also be classified into smaller subcategories, such as nanoplastics, which are even tinier than the width of a human hair.

Microplastics pose several risks to humans, ecosystems, and the environment:

Human health risks

Research has shown that microplastics can negatively affect human reproductive health, particularly in males. Additionally, microplastics and nanoplastics have the ability to cross organ boundaries and infiltrate cell walls, potentially carrying other harmful compounds like heavy metals or PFOS (per- and polyfluoroalkyl substances) with them. These substances can accumulate in the body and cause various health problems.

Harm to ecosystems

Microplastics can impact aquatic life, as they are often mistaken for food by marine and freshwater animals. This can lead to blockages in their airways and digestive tracts, and the toxins in microplastics can cause physiological stress, reproductive issues, and even death. Ingestion of microplastics by smaller organisms can also lead to bioaccumulation in the food chain, eventually impacting larger predators and human consumers.

Environmental impacts

Microplastics are pervasive in the environment, and their persistence and accumulation can result in long-term pollution. They have been found in various habitats, including oceans, rivers, lakes, soil, and even the air. The presence of microplastics in the environment also poses challenges for waste management, as they are difficult to remove from water and soil, and their degradation can take hundreds of years.

Due to their widespread presence and potential harm to humans and ecosystems, microplastics have become a growing concern for scientists, environmentalists, and policymakers. Efforts are being made to better understand their sources, movement, and impacts, as well as to develop strategies for mitigating their effects on the environment and human health.

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