Pollutant removal percentages for bioretention BMPs Pollutant removal percentages for bioretention BMPs. Source Winer, 2000. Practice TSS Total Phosphorus Total nitrogen Metals1 Bacteria Hydrocarbons Bioretention 802 100 for water that is infiltrated see [1] for water that passes through an underdrain 0 for water bypassing the bioretention BMP 50 95 352 80 1 Average of zinc and copper2 Assumed values based on filtering practice performance