Iowa's Water Pollution Crisis: Unveiling The Top Contaminant

Iowa's water bodies are severely polluted, with 751 impaired waters reported in 2022. The number one pollutant in Iowa's water bodies is silt (fine soil), which is carried to the water by surface runoff, wind, or stream bank erosion. Other common pollutants include E. coli, bacteria, chemicals, high levels of nitrates, phosphorus, and mercury. These pollutants can have serious health consequences, such as short-term health effects like nausea and headaches, and they can also be toxic to fish and other aquatic animals. The main sources of these pollutants are agricultural practices, including the use of manufactured fertilizers containing nitrogen and phosphorus for crop production, and animal waste.

Silt, fine soil, and sedimentation

Iowa's waterways are highly polluted, with the Iowa Department of Natural Resources (DNR) reporting 751 impaired waters in 2022. One of the major issues is siltation, or the undesired accumulation of sediments, which can have detrimental effects on the environment.

Siltation can be caused by a variety of factors, including soil erosion, construction activities, and the discharge of sewage sludge from households or businesses without proper septic systems. In rural areas, intensive or inadequate agricultural practices can lead to soil degradation and erosion, resulting in an increased amount of silt and clay in nearby water bodies. In urban areas, on the other hand, often face siltation due to construction activities, where the removal of vegetation leaves the area susceptible to erosion and the subsequent washing out of fines during rainstorms. Additionally, dredging and the transportation of dredged material can result in sediment spillage, contributing to siltation in water bodies.

The impact of siltation is far-reaching. It can affect navigation and irrigation channels, impeding the movement of vessels and disrupting water distribution. Siltation also acts as a pollutant for those who rely on clean water, including aquatic life such as coral polyps, mussels, and fish. The suspended sediment can smother sensitive organisms and reduce water quality.

To mitigate siltation, various strategies can be employed. In rural areas, the focus is on maintaining land cover and preventing soil erosion. Sediment control measures, such as trapping material before it reaches water sources, are crucial. In urban settings, minimizing the time that land remains uncovered during construction and using silt screens to prevent sediment release into water bodies are essential. Additionally, proper management of dredging operations and the efficient construction of sedimentation basins can help minimize siltation impacts.

While Iowa's impaired waters list does not specify the ranking of siltation as a pollutant, it is undoubtedly a significant contributor to the state's water quality issues. The presence of sedimentation and siltation in Iowa's water bodies underscores the need for effective erosion control and sediment management practices to restore and protect the state's aquatic ecosystems.

E. coli and bacteria

E. coli is a significant concern in Iowa's water bodies. The presence of this bacterium poses a risk to public health, and it is a leading cause of water pollution in the state. E. coli, or Escherichia coli, is a type of bacteria commonly found in the environment, including in water. While most strains of E. coli are harmless, some can cause serious illness if ingested or if people come into contact with contaminated water.

In Iowa, the detection of E. coli is a key indicator of water quality. The Iowa Department of Natural Resources (DNR) regularly monitors the state's waterways for the presence of E. coli and other pollutants. The DNR's impaired waters list, known as the 303(d) list, is submitted to the Environmental Protection Agency (EPA) every two years as required by the Clean Water Act. This list evaluates a range of water bodies, including lakes, rivers, streams, reservoirs, and wetlands, for various pollutants, with E. coli being a major concern.

E. coli contamination in Iowa's water bodies has been a persistent issue. In 2017, the DNR proposed a controversial rule change regarding the assessment of E. coli levels. The proposal suggested removing the Single Sample Maximum limit for E. coli bacteria, which would have impacted the listing of water bodies as impaired. Environmental advocates and groups, such as the Iowa Environmental Council and the Sierra Club Iowa chapter, raised concerns about this change. They argued that relying solely on average E. coli readings instead of the highest single measurement could jeopardize public health and result in an underreporting of impaired waters.

The presence of E. coli in Iowa's water bodies has multiple sources. Agricultural runoff, sewage discharges, and wildlife can all contribute to the contamination of waterways. High levels of E. coli can indicate the presence of other harmful pathogens, making recreation in affected waters unsafe. As a result, the DNR's impaired waters list plays a crucial role in identifying water bodies with elevated E. coli levels, prompting further investigation and remediation efforts to ensure the safety of Iowans and protect the state's water resources.

Nitrogen and phosphorus

Iowa's waterways are heavily polluted, with the Iowa Department of Natural Resources (DNR) reporting 751 impaired waters in 2022. The state's agricultural prowess, particularly in corn, soybean, pork, egg, and beef production, has come at a cost. Nitrogen and phosphorus pollution from farming practices have severely impacted Iowa's water quality, with far-reaching consequences.

The sources of nitrogen and phosphorus pollution in Iowa are diverse. The DNR attributes 80% of phosphorus and 92% of nitrate pollution to non-point sources, indicating agricultural practices as the primary contributors. Iowa's intense production of carbohydrates and protein has made it a leading contributor to nitrogen loads in the Gulf of Mexico, resulting in hypoxia, or "dead zones," where oxygen levels are too low to support marine life. This has severe implications for the Gulf's seafood industry.

To address the issue, Iowa implemented the Iowa Nutrient Reduction Strategy, aiming to reduce nitrogen and phosphorus levels leaving the state. However, despite significant spending, nitrogen pollution has worsened. This has prompted calls for stricter environmental laws and increased conservation practices. Scaling up conservation efforts and investing in nutrient reduction strategies are crucial to tackling the problem.

The impact of nitrogen and phosphorus pollution extends beyond Iowa. The state's contribution to nitrogen loads in the Mississippi and Missouri rivers is significant, with Iowa's nitrogen impact even greater in other watersheds. As a result, Iowa plays a dominant role in the Gulf hypoxia issue, underscoring the urgency of effective pollution reduction measures.

Pesticides and herbicides

Iowa's waterways are highly polluted, with 751 impaired waters reported in 2022. The Iowa Department of Natural Resources (DNR) is responsible for evaluating and monitoring the state's water bodies, including lakes, rivers, streams, reservoirs, and wetlands. While various pollutants are considered, one of the significant concerns in Iowa's water quality is the presence of pesticides and herbicides.

In Iowa, the Department of Agriculture and Land Stewardship plays a crucial role in addressing concerns related to pesticide use and drift. The department's Pesticide Bureau investigates complaints, helps protect citizens from pesticide misuse, and provides education and testing on the safe use of pesticides to licensed applicators. Iowans who suspect pesticide drift or have related concerns can reach out to the Pesticide Bureau for assistance and guidance.

To ensure responsible pesticide application, the Iowa Department of Agriculture and Land Stewardship enforces various regulations and provides investigative and enforcement actions. These actions include notices of violation, civil penalties, pesticide license suspension or revocation, and referrals to the Environmental Protection Agency (EPA) for further review and action. The department also emphasizes the importance of following label directions and supplemental labels to prevent off-site movement of pesticides, known as spray drift.

Water quality plays a crucial role in pesticide performance. Factors such as water temperature, hardness, and pH can influence the stability and effectiveness of pesticides and herbicides. For instance, water hardness, which is determined by the concentration of calcium and magnesium, can impact the absorption of pesticides by target plants. Additionally, water pH can affect the stability of pesticides in spray mixtures, and high concentrations of dissolved minerals can attract and bind pesticide molecules, hindering their absorption.

Understanding water quality and its interaction with pesticides is essential for effective pesticide application and environmental protection. By recognizing the potential impact of pesticides and herbicides on Iowa's water bodies, stakeholders can implement best practices, such as pre-treating water or using appropriate water sources, to minimize negative effects and ensure the sustainable use of these chemicals.

Industrial chemicals

The Iowa Department of Natural Resources (DNR) has detected PFAS in the water supplies of several communities across the state. In West Des Moines, for instance, PFAS levels in treated drinking water reached 5.3 parts per trillion, while untreated water in wells showed higher concentrations of 29 and 16 parts per trillion. These levels are still below the EPA's standard of 70 parts per trillion. The DNR also found PFAS in the water supplies of Central City, Ames, Sioux City, Rock Valley, and West Des Moines, with concentrations ranging from 2.1 to 9.6 parts per trillion.

The presence of PFAS in Iowa's water bodies can be attributed to upstream industrial facilities and wastewater plants. The state's proximity to the Mississippi River, a known source of PFAS contamination, also contributes to the issue. In 2018, Minnesota reached an $850 million settlement with 3M Company, a manufacturer of chemicals found in PFAS, due to groundwater contamination near the Mississippi River.

The Iowa DNR has taken steps to address the issue by testing water supplies in 59 cities, chosen based on their proximity to potential industrial sites that may use or store PFAS. The agency plans to test drinking water in additional cities, including Cedar Rapids. However, private wells, which provide 10% of drinking water to Iowans, are not currently being tested and remain largely unregulated.

The detection of PFAS in Iowa's water supplies underscores the pervasive nature of these "forever chemicals" and the challenges in managing their environmental and health impacts. The Iowa DNR's efforts to identify and address PFAS contamination are crucial in protecting the state's water resources and the health of its residents.

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