Lake Apopka's Polluted Waters: A Health Risk?

Lake Apopka, the fourth-largest lake in Florida, has a history of human alteration and pollution. Once a popular fishing destination, the lake has suffered from the discharge of nutrient-rich water and toxic chemicals, leading to algal blooms and a decline in fish populations. The pollution has also impacted the health of wildlife, with chemicals causing infertility and other disorders in several species. While restoration efforts have been made, the lake's water remains polluted, and it is not considered safe for swimming or other recreational activities. This raises the question: can the polluted water in Lake Apopka pose a health risk to humans and other organisms?

The impact of farms on Lake Apopka's water quality

Lake Apopka, Florida's fourth-largest lake, has experienced significant water quality issues due to the impact of surrounding farms. The lake, covering 30,909 acres, was once a popular tourist attraction and world-class bass fishery. However, farming activities in the region have severely degraded the lake's water quality, leading to a decline in fisheries and recreational value.

In the early 1900s, farmers cleared approximately 20,000 acres of wetlands, creating vast vegetable muck farms on the lake's north shore. These farms pumped phosphorus-filled and pesticide-laden wastewater back into the lake. The high nutrient content fuelled chronic algal blooms, blocking sunlight from reaching the lake's vegetation and causing the collapse of the bass fishery. The pesticides and herbicides that ran off into the lake for decades severely impacted the lake's ecosystem and hampered restoration efforts.

The negative effects of agricultural practices became evident in the 1970s. The excessive phosphorus levels in the lake's water spawned harmful algae blooms, leading to the death of aquatic life below the surface. This resulted in a decline in game fish populations and the closure of fish camps along the shoreline. The lake, once a vibrant fishing destination, transformed into a dead body of water.

To address the water quality issues, the state of Florida took action in the 1990s. In 1996, the Florida Legislature directed the St. Johns River Water Management District (SJRWMD) to buy out the farms on the lake's north shore. This pivotal decision marked the beginning of the lake's restoration process. The district, in collaboration with various partners, implemented a multipronged approach to improve water quality and restore fish and wildlife habitats.

The restoration efforts focused on reducing the amount of phosphorus entering the lake and removing the phosphorus already present. This involved restoring the area's wetlands to reduce water volume and treating all discharges to inactivate phosphorus. Additionally, the removal of rough fish, such as gizzard shad, and the operation of the marsh flow-way to filter algae, suspended solids, and nutrients contributed to the improvement in water quality. The combined effect of these measures resulted in a dramatic improvement, with a 69% decline in phosphorus concentrations and a 93% increase in water clarity by the end of 2023.

The ongoing restoration of Lake Apopka has yielded positive results, with native vegetation regrowing and the critical bass habitat recovering. The efforts to replant native vegetation, remove invasive plants, and restore wetlands demonstrate a commitment to reversing the damage caused by farming practices. While challenges remain, the collaborative efforts of various organizations provide hope for the lake's future and the legacy it will leave for future generations.

The role of phosphorus in the lake's pollution

Lake Apopka, located in Florida, has been subjected to extensive human alteration and pollution over the past century, leading to a decline in water quality and the health of its ecosystems. One of the primary pollutants is phosphorus, which has played a significant role in the lake's degradation. Here is an overview of the role of phosphorus in the pollution of Lake Apopka:

Sources of Phosphorus Pollution

Phosphorus pollution in Lake Apopka has primarily stemmed from agricultural activities and wastewater discharges. In the 1940s, a levee was constructed along the lake's north shore, draining a vast area of shallow marshland for agricultural use. This area, known as the North Shore Enhancement Area (NSEA), became a major source of phosphorus entering the lake. Agricultural runoff, rich in phosphorus, flowed into the lake, providing fuel for excessive algal growth.

Impact on Algal Blooms

The influx of phosphorus-laden water created a hypereutrophic condition in the lake. This led to chronic and continuous algal blooms, which had detrimental effects on the lake's ecosystems. The dense algal blooms blocked sunlight and depleted oxygen levels in the water, making it difficult for aquatic plants and fish populations to survive. As a result, the lake lost its recreational value and bass fishery, which was once a major tourist attraction.

Initiatives to Reduce Phosphorus

Recognizing the severity of the problem, several initiatives have been undertaken to reduce phosphorus levels in Lake Apopka. In 1991, the Friends of Lake Apopka (FOLA) was formed to reclaim the lake from agricultural interests. This led to the Lake Apopka Restoration Act in 1996, which provided funding to purchase and restore the farmland responsible for phosphorus discharges. The St. Johns River Water Management District (SJRWMD) set a phosphorus concentration target and worked towards reducing phosphorus loading from the NSEA.

Removal and Treatment Technologies

The Marsh Flow-Way, a constructed wetland, was established along the northwest shore of the lake to treat phosphorus-laden water. This system uses emergent vegetation to slow down the water flow, allowing suspended particles containing phosphorus to settle out. Additionally, innovative technologies, such as the Phosphorus Free Water Solutions project, have been implemented. This project focuses on completely removing soluble phosphorus from the ecosystem, returning clean water to the lake, and converting the removed phosphorus into potting soil.

Results and Ongoing Efforts

The efforts to reduce phosphorus pollution in Lake Apopka have shown significant results. Since the late 1980s, phosphorus concentrations have declined by 69%, and water clarity has improved. The regrowth of submerged aquatic vegetation and the recovery of bass habitats have been observed. However, ongoing challenges, such as the presence of invasive plant species, require continued monitoring and treatment. The restoration of Lake Apopka is an ongoing process, with multiple agencies working together to improve water quality and restore the lake's ecosystems to their former glory.

History of human alteration of the lake

Lake Apopka, located in Florida, has a history of human alteration dating back over 100 years. The first major change occurred in 1888 with the construction of the Apopka-Beauclair Canal, which remains the lake's only surface water outflow. In 1941, a levee was built along the north shore to drain 20,000 acres of shallow marsh for farming. This led to a discharge of nutrient-rich water into the lake, causing a chronic algal bloom that damaged the lake's recreational value and game fish populations.

In 1947, a hurricane destroyed much of the lake's aquatic vegetation, and the first of many recorded algae blooms occurred shortly after. The lake, once a world-class bass fishery and a popular tourist attraction, began to suffer from declining water quality.

In July 1980, the improper disposal of toxic chemicals by the Tower Chemical Company (TCC), a local pesticide manufacturer, resulted in a spill that contaminated Lake Apopka. Despite the subsequent shutdown of TCC and cleanup efforts, some chemicals seeped into the Florida aquifer and spread to other waterways. This incident caused health issues in the lake's wildlife, including infertility and other sexual disorders in several species.

In the late 1990s, birds around the lake were found dying in large numbers due to the effects of organochlorine pesticides used in agriculture. This event further highlighted the need for restoration efforts.

In 1991, the Friends of Lake Apopka (FOLA) was formed by a coalition of real estate interests aiming to reclaim the lake from agricultural interests discharging phosphorus-laden water. Their efforts, along with the 1996 Lake Apopka Restoration Act, led to the purchase of farmland and plans to convert the fields back into marshland. The restoration process included soil inversion to address high levels of pesticides and the application of soil amendments to trap excess phosphorus.

The St. Johns River Water Management District (SJRWMD) and its partners have been working on restoring the lake's wetlands, reducing phosphorus and suspended solids, and enhancing fish and wildlife habitats. The district has collaborated with agencies to purchase agricultural land, operate the marsh flow-way for filtration, harvest gizzard shad to reduce phosphorus, and replant native wetland vegetation. These efforts have resulted in significant improvements in water quality and clarity, with phosphorus concentrations declining by 69% and water clarity increasing by 93% as of 2023.

Health problems in wildlife caused by polluted water

Water pollution has devastating impacts on wildlife, causing a range of health problems. These issues are particularly prominent in Lake Apopka, Florida, which has been named the state's most polluted large lake. The lake has a history of human alteration, including agricultural activities and chemical spills, which have had detrimental effects on the health of its wildlife population.

One of the most significant consequences of water pollution in Lake Apopka is the disruption of the food chain. The discharge of nutrient-rich water from farms into the lake has resulted in a chronic algal bloom. This has led to a reduction in sunlight penetration and oxygen depletion, causing the loss of plant life and the death of aquatic organisms. The algal bloom has also contaminated the food chain, with birds accumulating harmful organochlorine pesticides (OCPs) by consuming contaminated fish. This has resulted in bird deaths, primarily among American white pelicans, wood storks, and great blue herons.

Additionally, water pollution in Lake Apopka has caused infertility and other sexual disorders in several species, including alligators. The presence of toxic chemicals, such as DDE, a known endocrine disruptor, has had significant impacts on the reproductive health of wildlife in the lake.

Water pollution can also lead to the spread of diseases among wildlife. Microbiological pollution, caused by microorganisms such as protozoa, viruses, and bacteria, can result in various diseases. Cholera and bilharzia are examples of waterborne diseases that can affect both humans and animals.

Furthermore, water pollution can cause skin diseases in wildlife. Arsenic, a common contaminant in drinking water, has been linked to skin disorders such as melanosis and keratosis. Exposure to polluted water can also lead to skin discomfort, such as rashes or itching, in swimmers and non-swimmers alike.

The impacts of water pollution on wildlife health are not limited to physical ailments but can also affect their behaviour and habitat. For example, in Lake Apopka, the decline in water quality has caused native aquatic plants to be outcompeted by invasive species, such as hydrilla. This has resulted in a loss of habitat for fish and other wildlife, further disrupting the ecosystem.

Overall, water pollution poses a significant risk to the health and well-being of wildlife, and the consequences can be long-lasting and challenging to mitigate.

Efforts to restore the lake's water quality

Efforts to restore Lake Apopka's water quality have been underway for several decades. The lake, which is the fourth-largest in Florida, suffered significant water quality degradation due to human alteration and pollution over the years. Here is a detailed account of the efforts to restore the lake's water quality:

Diet and Exercise Approach:

The St. Johns River Water Management District (SJRWMD) has adopted a multipronged approach called "diet and exercise" to restore the lake's water quality. The "diet" aspect focuses on reducing the amount of phosphorus entering the lake, while the "exercise" component involves removing phosphorus already present in the lake. This strategy has shown remarkable results, with a 69% decline in phosphorus concentrations and a 93% increase in water clarity as of 2023.

Farmland Buyouts:

In 1996, the Florida Legislature directed the district to buy out farms on the lake's north shore, which was a significant source of phosphorus pollution. This decision was a turning point as it reduced nutrient inputs and allowed for a shift in focus towards pollution removal.

Marsh Flow-Way:

The Marsh Flow-Way is an engineered wetland system constructed on 760 acres of the acquired farmland. It consists of levees, canals, and wetlands that act as a natural filter for the lake water. The system treats water pumped from Lake Apopka, removing phosphorus, algae, and suspended solids. From its opening until 2019, the Marsh Flow-Way removed an average of 2.2 metric tons of phosphorus and 4.3 tons of suspended solids annually.

Gizzard Shad Harvesting:

Harvesting gizzard shad, a native fish species, from the lake has been another effective measure. Gizzard shad feed on sediments, accelerating the nutrient cycling between floc sediments and lake water. By removing these fish, phosphorus and nitrogen are also eliminated from the lake, improving water clarity and reducing algae. From 1993 through December 2010, the harvesting removed more than 58 metric tons of phosphorus and 175 metric tons of nitrogen.

Plant Reintroduction:

The SJRWMD, in collaboration with researchers from the University of Florida, has been working on reintroducing native plant species such as Illinois pondweed (*Potamogeton illinoensis*) and eelgrass (*Vallisneria americana*). These plants are indicators of a healthy lake, and their presence accelerates the lake's recovery by improving water quality and providing habitat for aquatic life.

Upper Ocklawaha BMAP:

The Upper Ocklawaha Basin Management Action Plan (BMAP) was developed in 2007 to address water quality restoration goals and management actions. It identifies targets for water quality improvement, including nutrient removal through the marsh flow-way system and management of agricultural nutrient loading. The BMAP also incorporates an adaptive management approach to ensure flexibility and effectiveness in the restoration process.

The restoration of Lake Apopka's water quality is an ongoing process, and these efforts have already shown significant improvements. The combined actions of various organizations and the implementation of innovative strategies give hope for the lake's future and the well-being of the surrounding ecosystem.

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