Relative pollutant reduction from bioretention systems for metals, nitrogen, bacteria, and organics.
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Pollutant Constituent Treatment capabilities1
Metals2 Cadmium, Chromium, Copper, Zinc, Lead High
Nitrogen2 Total nitrogen, Total Kjeldahl nitrogen Low/medium
Bacteria2 Fecal coliform, e. coli High
Organics Petroleum hydrocarbons3, Oil/grease4 High

1 Low: < 30%; Medium: 30 to 65%; High: >65%
2 International Stormwater Database, (2012)
3 LeFevre et al., (2012)
4 Hsieh and Davis (2005).