Changes

With respect to potential contaminants or pollutants in stormwater surface runoff the types and levels of these contaminants varies widely depending on the associated activities, characteristics and makeup of the local source water area.

With respect to potential contaminants or pollutants in stormwater surface runoff the types and levels of these contaminants varies widely depending on the associated activities, characteristics and makeup of the local source water area.

[[File:Pollution hot spots.jpg|thumb|600px| Examples of activities that can lead to a source area being deemed a "Pollution hot spot" when it comes to surface runoff pollution (Photo Source: Müller et al. 2020<ref>Müller, A., Österlund, H., Marsalek, J. and Viklander, M. 2020. The pollution conveyed by urban runoff: A review of sources. Science of the Total Environment, 709, p.136125. https://www.sciencedirect.com/science/article/pii/S0048969719361212#f0010</ref>]]

[[File:Pollution hot spots.jpg|thumb|600px| Examples of activities that can lead to a source area being deemed a "Pollution hot spot" when it comes to surface runoff pollution (Photo Source: Müller et al. 2020<ref>Müller, A., Österlund, H., Marsalek, J. and Viklander, M. 2020. The pollution conveyed by urban runoff: A review of sources. Science of the Total Environment, 709, p.136125. https://www.sciencedirect.com/science/article/pii/S0048969719361212#f0010</ref>).]]

An area, for example that contains highly densified road networks and industrial areas that require large amounts of de-icing rock [[salt]] in the winter and experiences heavy traffic daily, make it a significant source of sodium, chloride, petroleum based hydrocarbons, [[heavy metals]] and finally pesticides to keep lawns green during the summer months. On the other hand a source area such as a [Blue roof] is only subject to atmospheric deposition of contaminants and isn't subjected to vehicular traffic sand, [[salt]] nor other de-icing agents. As a result, runoff from roofs typically contains significantly lower levels of [[heavy metals]], petroleum hydrocarbons, chloride or sodium levels and with more land in residential areas and less road networks is generally more suitable for safe infiltration of this runoff.

An area, for example that contains highly densified road networks and industrial areas that require large amounts of de-icing rock [[salt]] in the winter and experiences heavy traffic daily, make it a significant source of sodium, chloride, petroleum based hydrocarbons, [[heavy metals]] and finally pesticides to keep lawns green during the summer months. On the other hand a source area such as a [Blue roof] is only subject to atmospheric deposition of contaminants and isn't subjected to vehicular traffic sand, [[salt]] nor other de-icing agents. As a result, runoff from roofs typically contains significantly lower levels of [[heavy metals]], petroleum hydrocarbons, chloride or sodium levels and with more land in residential areas and less road networks is generally more suitable for safe infiltration of this runoff.