By Marlee L. Brown, Nathan Ivy, Melissa Gonzalez, Justin B. Greer, John D. Hansen, Edward Kolodziej, Jenifer K. McIntyre
Abstract
Extensive mortalities of adult coho salmon (Oncorhynchus kisutch), often called “Urban Runoff Mortality Syndrome” (URMS), have been documented during the fall in creeks where water quality has been degraded by roadway runoff. The primary cause of mortality is 6PPD-quinone (6PPDQ; N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine quinone)–an ozone transformation product that forms on all vehicle tires. Laboratory studies have shown that juvenile coho salmon are highly sensitive to 6PPDQ exposure. Unlike adults, juveniles reside in impacted watersheds year-round, including during the spring when 6PPDQ concentrations can frequently exceed lethal thresholds during storms. To assess the potential incidence of URMS in springtime rearing habitats for juvenile coho salmon, we conducted a paired water quality and toxicology study at Miller Creek, a runoff-impacted watershed in Normandy Park, WA, USA. Using a small field facility, three naïve groups of juvenile coho salmon (N = 720) were exposed to either creek water or groundwater (N = 120 per treatment per storm), across three spring storms while comparing water quality and mortality end points. In creek water during exposures, peak 6PPDQ concentrations reached 73–110 ng/L, exceeding reported median lethal concentrations (LC50) for coho salmon. Over each 24–73 h storm exposure period, ∼80% of Miller Creek-exposed juvenile salmon died. No mortality occurred among control fish exposed to groundwater. These results indicate previously unidentified mortality risks for juvenile life stages of coho salmon during spring storms, suggesting substantial and year-round water quality impediments to coho salmon health and recovery across roadway runoff-impacted spawning, rearing, and migratory habitats.
Urban stormwater runoff is increasingly recognized as a critical but underexplored pathway for per- and polyfluoroalkyl substances (PFAS) to enter aquatic environments. This work investigated the occurrence and behavior of 40 PFAS compounds in stormwater runoff entering a roadside rain garden in Secaucus, New Jersey, during six storm events between August 2023 and July 2024. Total PFAS concentrations (Σ40 PFAS) ranged from 1437 to 1615 ng/L, with perfluorobutane sulfonate (PFBS, 239–303 ng/L) and perfluorohexanoic acid (PFHxA, 115–137 ng/L) consistently emerging as dominant species. Perfluorocarboxylic acids (PFCAs) and perfluorosulfonic acids (PFSAs) together accounted for over 70% of the total PFAS mass. Despite its intended role in water quality improvement, the rain garden showed no measurable change in PFAS concentrations (differences of only 0.03–1.10%). These findings highlight the persistence and mobility of PFAS in urban stormwater runoff and the limited efficacy of conventional green infrastructure in mitigating PFAS contamination. Furthermore, they underscore the ineffectiveness of conventional green infrastructure for PFAS mitigation and the urgent need for advanced treatment technologies integrated into urban water management frameworks.
Per- and polyfluoroalkyl substances (PFAS) are human-made substances used in thousands of products, from medical devices to fire-fighting foam to oil- and stain-resistant coatings on carpets and packaging. They help make these products resistant to heat, water, stains, and grease. However, research over the past several decades has found evidence that PFAS persist in the environment for long periods of time, potentially leading to harmful human exposures.
A vernal pool wetland at Turnbull National Wildlife Refuge in late May that is seasonally dry. The lighter, cracked soil has dormant seed shrimp eggs scattered on the surface. Forested wetland at Mission Creek Park in early AprilSame forested wetland at Mission Creek Park in early JulyPacific treefrogVernal pool at Palisades Park in mid-April
Did you know that many of Washington’s wetlands completely dry out most years?
In fact, most wetlands in our state appear dry during much of the year. You might not recognize them as wetlands but they still perform vital functions such as improving water quality, storing flood waters, and providing habitat.
Wetlands are areas where water is at or near the soil surface for at least a couple of weeks during the growing season. In early spring, Washington’s wetlands typically have ponded water or saturated conditions which affect the types of plants that can grow there. When conditions are much drier, the influence of water still shapes the functions and values of those wetlands. Although it can be hard to identify wetland areas in late summer when they may appear as dry as the surrounding areas, it doesn’t make them any less important as waters of the state.
Wetlands have important seasonal functions
The seasonal drying cycle is an important process for maintaining water quality. The transition from anoxic conditions—when the wetland is full of water and there is no oxygen in the soil—to oxic conditions when the surface of the soil is exposed to oxygen—results in chemical changes that help reduce pollution.
For example, nitrogen is a common nutrient that degrades water quality. The element is an important crop fertilizer that is also released from other human activities such as combustion from fires and vehicle exhaust. Excess nitrogen not taken up by plants can cause algae blooms. Wetlands help process excess nitrogen and reduce adverse impacts on other waters. The seasonal oxic-anoxic transition in wetland soils is a big part of how they process that nitrogen. An excellent overview of that process is available here.
Towards summer’s end, many wetlands appear dry, but are on stand-by, ready to perform valuable functions as the rainy season approaches. Wetlands absorb and store precipitation during the wetter months. This slows the flow of water to Washington’s streams and rivers, preventing flooding and erosion. It also helps to recharge underground aquifers and keeps the water flowing in our streams and rivers when the weather is hot and dry again. As water is detained and stored in wetlands, sediment and pollutants are filtered out, which helps to improve and protect water quality.
Forested wetland at Mission Creek Park in early AprilSame forested wetland at Mission Creek Park in early July
Seasonally dry wetlands offer safe haven for some species
Pacific treefrog
Wetlands that dry out are important places for some wildlife. These species rely on habitat where fish and other predators requiring more permanent waters cannot survive. Washington’s state frog, the Pacific treefrog, is a small amphibian living throughout the state. They have loud voices that often fill the night with their calls, or chorusing, in the spring. They are also a favorite meal for many predators. These frogs specialize in seasonally dry habitats where they can get in and out of the water without encountering too many species wanting to eat them.
Adult treefrogs lay eggs in the early spring when wetlands have standing water. Then their tadpoles race the clock to metamorphose into tiny frogs and leave the wetlands before the water is gone.
Vernal pools: a unique type of seasonally dry wetland
One wetland that typically dries completely is a vernal pool. These wetlands hold water early in the growing season and then usually dry out within four months. They host unique plant and animal species adapted to these conditions. Vernal pools are one of the most important habitats for waterfowl migrating through Washington in the spring.
In addition, several species of fairy shrimp and seed shrimp rely on vernal pools for their life cycles. These invertebrates are specially adapted to wetlands that dry out, with a dormant life stage that rests in the dry soil of vernal pools until water becomes available again in the winter. You can find vernal pools throughout the Channeled Scablands and Columbia Plateau, as well as the San Juan Islands.
Vernal pool at Palisades Park in mid-AprilSame vernal pool wetland at Palisades Park in late May
Whether you’re exploring the back country, taking a day hike, or walking in a local park this summer, see if you can recognize the wetlands in our landscape, even if they are dry. They will transform once again when the seasonal rain and snow returns.
Today, Olympic View Water & Sewer District added a new “In the News“ page to track their Notice of Intent to sue Edmonds School District to protect the drinking water aquifer that is threatened by PFAS.
Citizen Suit Alleges Violations of Safe Drinking Water Act and WashingtonvState’s Non-Endangerment Standard for Underground Injection Control Wells
Edmonds, WA –Olympic View Water and Sewer District (OVWSD) has issued a Notice of Intent to Sue to the Edmonds School District to protect the drinking water aquifer that is threatened by PFAS (Per- and Polyfluoroalkyl Substances) pollution at the Madrona School. This legal action cites violations of environmental laws and follows the school district’s inaction in addressing the pollution.
One of the main pollution sources from urban and suburban communities is stormwater. Stormwater is rain and snow melt that flows over rooftops, streets, landscaping, and parking lots that can pick up and carry pollution into nearby waterways. Stormwater is not always treated even when it flows into street drains and can be a leading threat to water quality. Due to the significant rain and snow across the state, Washington has become a leader in stormwater management.
Per-and Polyfluoroalkyl Substances or “PFAS” has become an issue of public health concern in numerous contexts recently including in public drinking water supplies. PFAS are a large family of chemicals in use since the 1950s to make a wide variety of stain-resistant, water-resistant, and non-stick consumer products, including food packaging, outdoor clothing, and non-stick pans. PFAS have also been used in certain types of firefighting foams utilized by the U.S. military, local fire departments, and airports.
Vehicle tires contain the chemical known as 6PPD to prevent tires from breaking down due to reactions with ozone and other reactive oxygen species in the air. When 6PPD reacts with ozone in the air, it forms 6PPD-quinone. Tires wear down through contact with roads, releasing particles into the environment. When it rains, stormwater from hard surfaces like parking lots and streets washes these particles into streams and other water bodies. As a result, 6PPD-quinone may be present and aquatic organisms can be exposed to it.
Environmental Protection Agency Updated October 3, 2024
EPA is committed to providing meaningful, understandable, and actionable information on per- and polyfluoroalkyl substances – known as PFAS – to the American public. The information provided here is intended to explain some of the important background information needed to understand the details of specific actions EPA takes to address PFAS, and other emerging events related to PFAS.
The Model Toxics Control Act (MTCA) is Washington’s environmental cleanup law. MTCA funds and directs the investigation, cleanup, and prevention of sites that are contaminated by hazardous substances. It works to protect people’s health and the environment, and to preserve natural resources for the future.
There are about 14,000 known or suspected contaminated sites in Washington — and the list keeps growing. Thanks to cleanup efforts funded by MTCA, more than 7,700 of these sites are already cleaned up or require no further action.
On April 10, 2024, EPA announced the final National Primary Drinking Water Regulation (NPDWR) for six PFAS. To inform the final rule, EPA evaluated over 120,000 comments submitted by the public on the rule proposal, as well as considered input received during multiple consultations and stakeholder engagement activities held both prior to and following the proposed rule. EPA expects that over many years the final rule will prevent PFAS exposure in drinking water for approximately 100 million people, prevent thousands of deaths, and reduce tens of thousands of serious PFAS-attributable illnesses.
Environmental Protection Agency administrator Michael Regan speaks during a press briefing at the White House in Washington, on May 12, 2021. The Environmental Protection Agency has designated two “forever chemicals” that have been used in cookware, carpets and firefighting foams as hazardous substances.(AP Photo/Evan Vucci, File)
WASHINGTON (AP) — The Environmental Protection Agency on Friday designated two forever chemicals that have been used in cookware, carpets and firefighting foams as hazardous substances, an action intended to ensure quicker cleanup of the toxic compounds and require industries and others responsible for contamination to pay for its removal.
