Typical concentrations of pollutants in stormwater runoff and snowmelt runoff for select cities
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Constituent (concentrations reported in mg/L) Annual Twin Cities Snowmelt4
Twin Cities1 Marquette MI2 Madison WI Storm Sewers Open Channels Creeks NURP5
Cadmium 0.0006 0.0004
Copper 0.022 0.016
Lead 0.060 0.049 0.032 0.16 0.2 0.08 0.18
Zinc 0.111 0.203
Biological Oxygen Demand 15
Chemical Oxygen Demand 169 66 169 82 84 91
Total Kjeldahl Nitrogen 2.62 1.50 3.52 2.36 3.99 2.35
Nitrate + Nitrite 0.53 0.37 1.04 0.89 0.65 0.96
Ammonia 0.2
Total Phosphorus 0.58 0.29 0.66 0.7 0.56 0.54 0.46
Dissolved Phosphorus 0.20 0.04 0.27 0.25 0.18 0.16
Chloride3 230 49 116
Total Suspended Solids 184 159 262 148 88 64
Volatile Suspended Solids 66 46 15

1 Event mean concentrations; Reference: Brezonik and Stadelmann 2002
2 Geometric mean concentrations; Reference: Steuer et al. 1997
3 Geometric mean concentrations; Reference: Waschbusch et al. 1999
4 Reference: Oberts, G. (Met Council). 2000. Influence of Snowmelt Dynamics on Stormwater Runoff Quality.
5 Reference: Median concentrations from more than 2,300 rainfall events monitored across the nation; EPA, 1983

This page was last edited on 16 April 2020, at 18:14.

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