Concentrations of contaminants found in stormwater
Concentrations of contaminants found in stormwater. Note that median concentrations are lower than event mean concentrations shown in this manual. This is because concentration data is typically positively skewed. Source: International Stormwater Database.7. Note that the table does not include information for chloride, a common pollutant in stormwater. Chloride concentrations vary seasonally and would be misrepresented in a single table. For more information on chloride concentrations in stormwater, see here.
Link to this table.
| Land use | TSS 1 | NO2 + NO3 1 | TN 1 | TP 1 | Cu 2 | Zn 2 | Ni 2 | Cd 2 | Cr 2 | CN 2,5 | Oil and grease 2 | VOCs 2,5 | Pesticides 2,4,5 | FC 3,5 | EC 3,5 | FS 3,5 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Commercial | ||||||||||||||||
| Number of sites | 56 | 50 | 13 | 56 | 60 | 62 | 40 | 51 | 38 | 2 | 44 | 4 | 1 | 4 | -- | 3 |
| Number of observations | 857 | 786 | 77 | 948 | 785 | 867 | 291 | 543 | 294 | 6 | 394 | 160 | 6 | 19 | -- | 7 |
| % of samples above detection | 98.7 | 98.9 | 97.4 | 94.5 | 85 | 99.2 | 51.5 | 38.1 | 52.0 | 0 | 65.5 | 65.5 | 0 | 73.7 | -- | 100 |
| Minimum | <0.5 | <0.1 | <1.5 | <0.01 | <0.2 | <0.3 | <1 | <0.03 | <0.7 | n/a | <0.5 | <0.05 | n/a | <200 | -- | 310 |
| Maximum | 2385 | 8.2 | 18.1 | 4.27 | 569.1 | 3050.5 | 110 | 80 | 100 | n/a | 359 | n/a | 28000 | -- | 24000 | |
| Median | 52 | 0.6 | 1.75 | 0.2 | 17 | 110 | 8 | BDL6 | 4 | BDL | 5 | 0.7 | n/a | 450 | -- | 3100 |
| Industrial | ||||||||||||||||
| Number of sites | 58 | 51 | 13 | 57 | 65 | 67 | 43 | 60 | 42 | 2 | 48 | 3 | -- | 6 | -- | 4 |
| Number of observations | 619 | 536 | 85 | 638 | 569 | 627 | 300 | 525 | 312 | 9 | 370 | 144 | -- | 32 | -- | 12 |
| % samples above detection | 99.5 | 97.0 | 95.3 | 95.1 | 85.1 | 98.9 | 58.0 | 48.6 | 72.4 | 0 | 59.7 | 10.4 | -- | 90.6 | -- | 91.7 |
| Minimum | <1 | <0.02 | <1.5 | <0.02 | <0.2 | <0.5 | <2 | <0.03 | <0.7 | n/a | <0.5 | <0.05 | -- | <1 | -- | <1 |
| Maximum | 2490 | 8.4 | 15.2 | 7.9 | 1360 | 8100 | 120 | 334 | 150 | n/a | 408 | -- | 3600000 | -- | 48000 | |
| Median | 75 | 0.68 | 1.7 | 0.23 | 19 | 155 | 10 | BDL | 10 | BDL | 5 | BDL | -- | 3950 | -- | 24000 |
| Residential | ||||||||||||||||
| Number of sites | 146 | 127 | 20 | 148 | 147 | 151 | 77 | 114 | 72 | -- | 95 | 7 | 1 | 10 | 3 | 4 |
| Number of observations | 2257 | 1772 | 131 | 2380 | 1743 | 2013 | 418 | 1123 | 408 | -- | 694 | 210 | 6 | 94 | 19 | 23 |
| % of sample above detection | 99.9 | 99.0 | 98.5 | 98.2 | 86.5 | 97.0 | 42.2 | 40.4 | 48.8 | -- | 56.8 | 20.1 | 0 | 85.9 | 100 | 95.7 |
| Minimum | <0.5 | <0.03 | <1.5 | <0.01 | <0.2 | <0.5 | <0.5 | <0.03 | <0.7 | -- | <0.5 | <0.05 | n/a | <1 | 10 | <1 |
| Maximum | 4168 | 66.4 | 18.3 | 19.90 | 590 | 14700 | 100 | 70 | 70 | -- | 419 | 3.42 | n/a | 5230000 | 35000 | 200000 |
| Median | 58 | 0.60 | 2.24 | 0.26 | 11 | 69.9 | 5 | BDL | 3 | -- | 4 | BDL | BDL | 9400 | 1000 | 23500 |
| Open space | ||||||||||||||||
| Number of sites | 15 | 13 | 4 | 15 | 12 | 12 | 9 | 8 | 7 | 3 | 9 | 1 | -- | 2 | 1 | -- |
| Number of observations | 105 | 109 | 13 | 111 | 44 | 49 | 38 | 41 | 36 | 13 | 26 | 5 | -- | 6 | 5 | -- |
| % of samples above detection | 97.1 | 92.7 | 92.3 | 93.7 | 64.4 | 65.3 | 23.1 | 39.0 | 36.1 | 15.4 | 34.6 | 60.0 | -- | 100 | 100 | -- |
| Minimum | <1 | <0.1 | <0.5 | <0.01 | <0.8 | <5 | <2 | <0.04 | <0.7 | <0.01 | <1 | <0.2 | -- | 1900 | 100 | -- |
| Maximum | 4168 | 3.4 | 3.3 | 0.76 | 210 | 390 | 100 | 8 | 120 | 0.08 | 11 | 0.84 | -- | 63000 | 4700 | -- |
| Median | 58 | 0.5 | 1.1 | 0.129 | 6 | 25 | BDL | BDL | BDL | BDL | BDL | 0.77 | -- | 2150 | 1100 | -- |
| Rooftop | Water quality from rooftops varies with the type of roof. For more information see the section on Water quality considerations for stormwater and rainwater harvest and use/reuse | |||||||||||||||
TSS=total suspended solids, NO2=nitrite, NO3=nitrate, TN=total nitrogen, Cl=chloride, Cu=copper, Zn=zinc, Ni=nickel, Cd=cadmium, Cr=chromium, CN=cyanide, VOC=volatile organic compound, FC=fecal coliform, EC=E. coli, FS=fecal streptococci
1 Concentrations are in milligrams per liter
2 Concentrations are in micrograms per liter
3 Concentrations are in Number per 100 milliliters
4Data is for trans-1,3-Dichloropropene and bromomethane
5 Data was selected from states with a similar climate to MN. The appropriate states were determined using Figure 1.3 from the Stormwater BMP Design Supplement for Cold Climates document.
6BDL = below detection level
7The following censoring techniques were used for this data:
- If detection rates were 90% or greater, a value of "0" was substituted for non-detects.
- If detection rates were greater than 50% but 90% or less, a value of 1/2 the detection limit was substituted for non-detects.
- If detection rates were 50% or less, the median was assumed to be below the method detection level.