Biscayne Bay, a vibrant coastal ecosystem in Miami, Florida, faces a growing threat from PFAS, or “forever chemicals.” These persistent pollutants, known for raising health concerns nationwide, find their way into the bay through leaching from failing septic systems, landfills, and runoff from airport runways and agricultural fields. Consequently, they end up affecting marine life such as fish, dolphins, manatees, sharks, and other species that call the bay home.
Researchers from Florida International University’s Institute of the Environment have been studying the risks posed by PFAS in coastal environments like Biscayne Bay. With the potential for these chemicals to enter the food chain and accumulate in marine plants and animals, including fish consumed by humans, there are significant ecological and human health implications. A recent study aimed to trace the origins of PFAS contamination in Biscayne Bay to identify possible ways to mitigate the harm caused by these chemicals.
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What are PFAS?
PFAS, or perfluoroalkyl and polyfluoroalkyl substances, are a group of synthetic chemicals that have been utilized for over five decades. These substances can be found in a variety of everyday products, such as personal care items like cosmetics and shampoos, as well as nonstick cookware and water-repellent coatings for food packaging. Additionally, PFAS are used in adhesives and aqueous film-forming foams for firefighting purposes.
Over time, due to their widespread use and disposal, these chemicals have dispersed into the environment, infiltrating aquatic ecosystems like surface water, groundwater, and coastal areas. One of the reasons PFAS are referred to as “forever chemicals” is because of their stability and resistance to degradation. This property, although useful in certain products, makes it extremely difficult to eliminate these chemicals from the environment. As a result, PFAS can persist for decades or even centuries, creating concerns about their potential toxicity and impact on human health and ecosystems.
How PFAS Enter the Marine Environment
PFAS, or per- and polyfluoroalkyl substances, have been detected in high concentrations near urban canals in the Biscayne Bay area, particularly around the Miami River, Little River, and Biscayne Canal. These canals contribute to the presence of PFAS in offshore regions of the Atlantic Ocean.
There are several sources of PFAS contamination, including:
- Sewage contamination from malfunctioning septic systems and wastewater leaks in urban areas. These contribute PFAS types commonly found in stain and grease repellents, carpets, food packaging materials, and household products such as PFOS, PFOA, PFPeA, PFHxS, PFHxA, PFBA, and PFBS.
- The use of 6-2 FTS, a fluorotelomer PFAS, in aqueous film-forming foam at military and airport facilities. This is especially notable in the Miami River, which flows past industries, rail yards, and Miami International Airport before reaching Biscayne Bay.
A study used a model to predict the dispersion of PFAS by ocean currents from these canals into coastal areas. The model revealed that:
- PFAS concentrations were highest near the canals and decreased along the bay as ocean water became deeper and more saline, which reduces the solubility of PFAS.
- Surface waters near land had PFAS concentrations almost six times higher than samples collected 13 to 33 feet (4 to 10 meters) below the surface in the bay and offshore. This suggests that pelagic fish inhabiting surface waters, such as mackerel, tunas, and mahi-mahi, are at the highest risk of exposure.
How Marine Organisms are at Risk
Even though the PFOS and PFOA levels in the study were below the Florida Department of Environmental Protection advisory levels for human health exposure in surface water, the existing guidelines might not adequately safeguard both human and marine life. These chemicals tend to accumulate through the food chain, potentially posing a higher risk to top predators, such as dolphins, sharks, and humans who consume fish.
Taking water samples in Biscayne Bay revealed that various types of PFAS identified are unregulated, and their potential toxicity remains uncertain. With this in mind, there is an urgent need for federal and state agencies to establish guidelines and implement action plans that protect people and marine life in Biscayne Bay. This includes addressing adverse effects on numerous marine species, such as fish, manatees, dolphins, sharks, and seagrass, as well as the broader ecosystem and food chain involving pelagic fish like mackerel, tunas, and mahi-mahi.
What You Can Do About It
Considering the prevalence of PFAS in various water systems in South Florida and their presence in coastal waters globally, it’s crucial to find ways to limit the presence of these chemicals in our environment. While researchers work tirelessly to find effective methods of eliminating and removing PFAS from water, food, and the environment, individuals have the power to reduce their use and consumption of PFAS-containing products. By doing so, they can help minimize the amount of these toxic chemicals that ultimately end up in our marine environment.
To help with conservation efforts and the protection of human health, residents are encouraged to be mindful of their usage and selection of everyday items that might contain PFAS. Some common products to watch for include:
- Teflon nonstick cookware: Consider opting for alternative cooking surfaces, such as cast iron or stainless steel.
- Food packaging: Be aware of fast-food wrappers and popcorn bags, which may contain PFAS chemicals. Choose packaging made from more eco-friendly materials.
- Water-resistant clothing and cosmetics: Look for clothing made from natural fibers and cosmetics that do not use PFAS in their formulations.
- Treated carpets: When purchasing carpets, avoid those treated with stain-resistant chemicals that may contain PFAS.
It’s important to note that state agencies and local authorities play a crucial role in managing the health concerns associated with PFAS contamination. They must develop comprehensive guidelines and ordinances to regulate the usage and disposal of PFAS-containing products. By working together with businesses, state agencies can encourage the development of safer alternatives in the market.