Emerging Contaminants
Emerging contaminants are those that have been recently detected or discovered through monitoring, though the specific contaminants may have been present in the environment for some time. From pesticides to pharmaceuticals to blue-green algae, emerging contaminants are of growing concern to aquatic environments.
Pesticides and pharmaceuticals
Pesticides are transported to water bodies via nonpoint source pathways, primarily from agricultural lands. Pharmaceuticals pass through the human body, exit as waste, and even after passing through wastewater treatment plants and septic systems, can persist in aquatic environments. Pharmaceuticals from livestock use are also increasingly present in soil and water. Together, pesticides and pharmaceuticals include thousands of chemical compounds with widely varying degrees of toxicity, persistence, and bioaccumulation potential.
Blue-green algae
Blooms of blue-green algae, also referred to as “Harmful Algal Blooms” (HABs), are fueled by excess waterborne nutrients, primarily from agricultural lands. Blue-green algae blooms are highly dynamic, exhibiting wide seasonal fluctuations, and are of particular public health concern due to their potential to release cyanotoxins (e.g., microcystin) that are harmful to people and pets.
Per- and polyfluoroalkyl substances (PFAS)
PFAS are widely used, long-lasting chemicals, components of which break down very slowly over time—lending these substances their moniker of “forever chemicals.” There are thousands of PFAS chemicals, found in numerous consumer, commercial, and industrial products—making it particularly challenging to study and assess the potential human health and environmental risks.
Microplastics
Plastics are ubiquitous in nearly every facet of our daily lives. While plastics break down into smaller and smaller pieces over time, they never fully degrade—not in our lifetimes. Microplastics, defined as any plastic debris <5mm in length, have the potential to wreak havoc on aquatic ecosystems. The three largest sources of microplastics to aquatic environments include synthetic textiles (clothing and fishing nets), car tires, and city dust. Fast fashion is a major culprit, with a single synthetic textile (e.g., polyester, nylon, spandex, acrylic, rayon) garment shedding over 19,000 microfibers per wash!
Video Resources
The Plastic Problem – PBS NewsHour
Enhanced Learning Activities
How Much Garbage Is That?! (Grades 6-12)
I Spy: Plastics and Bioaccumulation (Grades 6-12)
Additional Resources
Iowa's Ambient Water Quality Monitoring and Assessment Program – Iowa Department of Natural Resources
A Closer Look: Harmful Algal Blooms – Iowa State University | Conservation Learning Group
PFAS Explained – U.S. Environmental Protection Agency