BIOSWALES HOW EFFICIENT ARE THEY?

This data was obtained from The State of Oregon Department of Environmental Quality. These tests were done on bioswales with specific parameters, however, they are comparable to other research documents.
Obtainable reductions of pollutants in bioswales:
Total Suspended Solids – 83 to 92%
Turbidity (with 9 minutes of residence) – 65%
Lead – 67%
Copper – 46%
Total Phosphorus – 29 to 80%
Aluminum – 63%
Total Zinc - 63%
Dissolved Zinc – 30%
Oil/Grease – 75%
Nitrate-N – 39 to 89%