That’s why they are mandated by Florida regulations: To protect rivers and lakes from the suburban runoff. The article from the Orlando Sentinel: http://bit.ly/32Yid8n begins with:
Regional water managers began requiring these ponds a decade ago to catch dirty rainwater running off streets and parking lots before it flowed into clean rivers and lakes.
Now scientists are re-evaluating these panaceas, concerned that the ponds may be causing another environmental problem.
Scientists know that toxic metals from gasoline, motor oil, rubber and asphalt settle to the bottom of these retention ponds, accumulating in the sediment. Now a regional biologist who is studying the man-made ponds says that fish feeding on organisms in the sediment also pick up these toxic metals.Orlando Sentinel, 11/18/2020