Advanced water testing around the Palma Sola Causeway in Southwest Florida detected horse DNA in fecal bacteria at three of four sampled sites, confirming horses as a source of water contamination. However, the levels were too low to quantify the exact contribution of horse feces to overall bacterial presence. Birds were also identified as a source at one site. These findings add complexity to the ongoing debate about the environmental impact of horseback riding in the bay, with scientists calling for further testing to better understand the extent of contamination and its implications for water quality.

Horseback riding companies argue that the minimal detected levels indicate effective waste management practices, including cleanup crews that remove horse manure before and during rides. Both sides acknowledge the potential need for regulation, though horseback riding operators caution against premature restrictions without more conclusive data. Proposed regulatory measures could include limiting horse access to certain areas or implementing permitting systems, aiming to balance recreational use with environmental protection and other community interests in Palma Sola Bay.