science

Illustration by Melody Mullaly.

We are increasingly dumping waste into our water. And it’s made a difference. 

Water. We cook with it. We swim and play in it. We grow our food with it and travel on it. We like to look at it and, ultimately, drink it.  And 10 percent of Alachua County is covered in it, a result of Florida’s submerged past: Millions of years ago, most of North Florida (including Alachua County) was under water. When the water receded, it left behind remains of coral that compacted into limestone. Over time, erosion of this limestone yielded a unique type of landscape known as karst, which is responsible for our Swiss cheese patchwork of lakes, springs, aquifers and rivers.

Unfortunately, as industry and growth accelerate, we are increasingly dumping waste into our water. And it’s made an impact. At least half of the 40 named waterways in Alachua County are impaired. As recently as 2015, the Alachua County Environmental Protection Department announced that Hogtown Creek, which runs through the heart of Gainesville, had at least four times the maximum allowed concentration of fecal bacteria colonies. The City of Gainesville recently posted signs warning potential bathers or fossil hunters to avoid getting water in their mouth, ears or eyes. Additionally, Lake Newnan, one of the largest lakes in Alachua County, has about double the target concentrations of nitrogen and phosphorus, as well as double the ideal concentration of chlorophyll-a, a pigment that indicates the amount of algae in the lake.

sciene info2 (1)Water pollution around the country is a concern, said Stacie Greco, water conservation coordinator at the Alachua County Environmental Protection Department, and Alachua County is no different. Urban streams like Hogtown Creek are especially affected. Many of these urban waterways are inundated with fecal bacteria from pet and human waste, as well as surface pollutants such as oil from roads, pesticides, fertilizers and yard waste. Pollution is especially high after storms, which carry pollutants down storm drains into surface or groundwater.

The quality of the pollutants is also important to consider. Many pollutants unintentionally added by people, such as fertilizers, are nutrients for more than just your plants — algae and bacteria thrive off on them, too, and large inputs of nutrients into a basin can allow harmful microorganisms to bloom and increase exponentially. And just like humans, these microbes respire, which removes oxygen from the water and suffocates fish and plants.

In Alachua County, researchers have known for decades that this effect, known as eutrophication, occurs in lakes such as Lake Newnan and Lake Wauberg. Half a dozen agencies periodically measure the dropping dissolved oxygen concentration and the level of pigments derived from the algae in the water. The Florida Fish and Wildlife Conservation Commission has measured declining sport fish populations since the early 1980s in Lake Newnan, and Lake Wauberg has been eutrophic since at least 1990. Often, Greco said, the source of these nutrients in rural waterways is farm waste or fertilizer runoff from lawns, as is the case in Lake Newnan. This is the same type of process that leads to the analogous red tide seen along Florida shores, which can lead to massive fish die-offs, skin rashes and harmful accumulation of toxins in shellfish.

Left untreated, eutrophic lakes can become completely barren of life and unusable for fishing or recreation. One of the most widely known examples of this is in Central Florida. Lake Apopka, near Orlando, used to be renowned worldwide for its sport fishing and clear water. As nutrients from surrounding farms began leaching into the water, said Susan Curry, a professor of environmental management at UF, the population of game fish declined. Soon the lake became murky and unusable for recreation. The clean-up effort has come at a cost for Orange County — nearly $200 million.

Contamination is also a critical quality issue facing local waterways. Like nutrients, contaminants such as heavy metals, chemicals and fecal bacteria can also run off into the water. Both can cause big problems to wildlife and humans. In the case of Lake Apopka, improper dumping of toxic chemicals only compounded water quality issues. While heavy metals such as lead or cadmium are less common pollutants in watersheds here where there is less industry, bacteria such as E. coli, mostly from pet waste runoff and faulty septic tanks, has impaired local waterways. In addition to Hogtown Creek, several other nearby waterways including Sweetwater Branch and Orange Creek are impaired, Greco said.

While measuring pollutant concentrations may be relatively straightforward, managing an impaired waterway isn’t always easy, Greco said. A lot of it comes from understanding exactly where the pollution comes from. Pollutants are defined by scientists as either point-source or nonpoint-source, Curry said. The former refers to an identifiable source (such as a pipe from an industrial plant), the latter to non-discernable or ambiguous sources (such as stormwater runoff from an entire neighborhood). Additionally, waterways are classified by their use, whether for water, shellfish propagation, fishing and recreation, or navigation and industry.

Although the details get pretty technical and the acronyms get increasingly frequent and confusing, basically the 1972 Clean Water Act, signed into law by Richard Nixon, outlined two main ways to limit pollution into water, Greco said. This is included in a Basin Management Plan for the waterway, available online to the public, which outlines how to clean up an impaired waterway. For point-source pollution, such as discharge from a dairy farm, farmers must get a permit to dump their waste and can only dump up to a level deemed safe by the Environmental Protection Agency, called a Total Maximum Daily Load. Nonpoint sources, however, are more complicated. For these, pollutants may be physically separated from the watershed by retention ponds or buffers; or communities can adopt Best Management Practices (BMP) to limit the amount of pollution allowed.

For Gainesville, this means a dedicated team of water quality scientists is always on hand to measure water quality markers and discern the possible sources of pollution into our watersheds. Additionally, local industries and farms are educated on BMPs and permits to make sure their waste is properly managed.

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