The water's surface on Florida's Indian River Lagoon is not considered toxic. However, the lagoon is designated as an "impaired water" under the Clean Water Act, and the Florida Department of Environmental Protection (FDEP) has issued several advisories warning of potential health hazards associated with swimming, fishing, and other activities in the lagoon.

Some of the potential contaminants found in the Indian River Lagoon include:

* Nutrients: Excess nutrients from fertilizers and wastewater runoff can lead to algal blooms and other water quality problems. Algal blooms can produce toxins that can be harmful to humans and wildlife.

* Bacteria: Bacteria from human and animal waste can contaminate the lagoon and cause gastrointestinal illness in people who come in contact with the water.

* Pesticides: Pesticides used in agriculture and lawn care can also contaminate the lagoon and pose a health risk to humans and wildlife.

* Heavy metals: Heavy metals such as lead and mercury can accumulate in the tissues of fish and other aquatic organisms and can pose a health risk to humans who consume these organisms.

The FDEP advises that people should always follow the latest health advisories when swimming, fishing, or engaging in other activities in the Indian River Lagoon. The department also encourages people to take steps to reduce their environmental impact, such as using fertilizers and pesticides sparingly, and properly disposing of human and animal waste.