Pollution Prevention - Urban Watersheds: Geology, Contamination, and Sustainable Development - page 458

FIGURE 13.13
Construction of a deep-shaft combined sewer basin. (Photo by Kent S. Murray.)
fertilizers and pesticides due to concerns over cultural eutrophication. It would be good
practice if every homeowner considering the use of a timed fertilization program offered
by “lawn care experts” would conduct an inexpensive soil sample to assess the level of
nutrients already present in the soil. Most lawns do not need four to six fertilization/
herbicide applications per season.
Heavy metals are a major concern in the near-surface soils and groundwater of urban
areas (Murray et al. 2006). Eliminating the use of lead in paints and chromium in some
industrial applications will help lower their presence in stormwater runoff. Some elimina-
tion of metals from stormwater can also be achieved by protecting the soil from erosion in
areas where metal contamination is high.
13.4.1.5.2 Substitution
Contaminants released into stormwater by lawns can be significantly reduced through
better lawn management. Most state universities have agricultural extension services, and
these organizations offer excellent advice on how to reduce the amount of fertilizer used
and identify the least environmentally offensive types.
Road salt is a significant contaminant of surface waters and groundwater. A survey of
23 springs in the Greater Toronto Area of southern Ontario recorded chloride contamina-
tion levels, resulting from the winter application of road deicing salt, ranging from <2
to >1200 mg L −1 (Williams et al. 2000). In another study, runoff from the application of
road salts as a deicer led to the widespread contamination of groundwater and effectively
changed the chemistry of the Rouge River due to groundwater discharge to this surface
water body (Xun and Murray 2002). Many communities, especially those with lakes pres-
ent, substitute sand for road salt.
13.4.1.5.3 Prevention
Soil stabilization—especially at construction sites—can help prevent erosion and the
transport of contaminated soil by stormwater. One activity not used enough for prevent-
ing soil erosion is the inspection of erosion control measures after rainstorms. Another
frequent problem is the failure of communities to require the collection of soil samples for
textural analysis before development occurs at a site (Kaufman 2000). Basic information