Changes

==De-icing Salt==

==De-icing Salt==

 

[[File:Snow_filter_strip.png|thumb|Snow being stored on a filter strip in Markham, ON]]

[[File:Snow_filter_strip.png|thumb|Snow being stored on a filter strip in Markham, ON]]

Sodium and chloride ions in de-icing salts applied to asphalt areas travel easily with the runoff water. De-icing salt can increase the mobility of some [[heavy metals]] in soil (e.g. lead, copper or cadmium). This may increase the downstream concentration of these metals <ref>Amrhein, C., Strong, J.E., and Mosher, P.A. 1992. Effect of de-icing salts on metal and organic matter mobilization in roadside soils. Environmental Science and Technology. Vol. 26, No. 4, pp. 703-709</ref><ref>Bauske, B., Goetz, D. 1993. Effects of de-icing salts on heavy metal mobility. Acta Hydrochimica Hydrobiologica. Vol. 21. pp. 38-42., 1993).</ref>

Sodium and chloride ions in de-icing salts applied to asphalt areas travel easily with the runoff water. De-icing salt can increase the mobility of some [[heavy metals]] in soil (e.g. lead, copper or cadmium). This may increase the downstream concentration of these metals <ref>Amrhein, C., Strong, J.E., and Mosher, P.A. 1992. Effect of de-icing salts on metal and organic matter mobilization in roadside soils. Environmental Science and Technology. Vol. 26, No. 4, pp. 703-709</ref><ref>Bauske, B., Goetz, D. 1993. Effects of de-icing salts on heavy metal mobility. Acta Hydrochimica Hydrobiologica. Vol. 21. pp. 38-42., 1993).</ref>

Very few studies have sampled groundwater below infiltration facilities or roadside ditches receiving de-icing salt laden runoff have found concentrations of heavy metals that exceed drinking water standards <ref>Howard, K.W.F. and Beck, P.J. 1993. Hydrogeochemical implications of groundwater contamination by road de-icing chemicals. Journal of Contaminant Hydrology. Vol. 12. pp. 245-268.</ref><ref>Granato, G.E., Church, P.E., Stone, V.J. 1995. Mobilization of Major and Trace Constituents of Highway Runoff in Groundwater Potentially Caused by De-icing Chemical Migration. Transportation Research Record. No. 1483.</ref>

Very few studies have sampled groundwater below infiltration facilities or roadside ditches receiving de-icing salt laden runoff have found concentrations of heavy metals that exceed drinking water standards <ref>Howard, K.W.F. and Beck, P.J. 1993. Hydrogeochemical implications of groundwater contamination by road de-icing chemicals. Journal of Contaminant Hydrology. Vol. 12. pp. 245-268.</ref><ref>Granato, G.E., Church, P.E., Stone, V.J. 1995. Mobilization of Major and Trace Constituents of Highway Runoff in Groundwater Potentially Caused by De-icing Chemical Migration. Transportation Research Record. No. 1483.</ref>

To minimize risk of groundwater or soil contamination, the following management approaches are recommended (Pitt et al., 1999; TRCA, 2009b):

===To minimize risk of groundwater or soil contamination, the following management approaches are recommended (Pitt et al., 1999; TRCA, 2009b):===

 

Stormwater infiltration practices should not receive runoff from the following areas:  

Stormwater infiltration practices should not receive runoff from the following areas:  

*Where large amounts of de-icing salts are applied (e.g., busy highways), or  

*Where large amounts of de-icing salts are applied (e.g., busy highways), or  

*Pollution hot spots (e.g. vehicle fuelling, servicing or demolition areas, outdoor storage or handling areas for hazardous materials, and some heavy industry sites); *Prioritize infiltration of runoff from source areas that are comparatively less contaminated such as roofs, low traffic roads and parking areas; and

*Pollution hot spots (e.g. vehicle fuelling, servicing or demolition areas, outdoor storage or handling areas for hazardous materials, and some heavy industry sites); *Prioritize infiltration of runoff from source areas that are comparatively less contaminated such as roofs, low traffic roads and parking areas; and

*Apply [[pretreatment]] practices before infiltration of road or parking area runoff.

*Apply [[pretreatment]] practices before infiltration of road or parking area runoff.

==Other freezing related concerns==

==Other freezing related concerns==