2.2 Landfill sites and contaminated lands

Ontario has over 4,000 landfill sites, all of which are listed in the Ministry of the Environment Publication, Waste Disposal Site Inventory. This 200-page book categorizes these sites according to whether they are open or closed and to the risk they pose to the human and natural environment. Its maps identify the waste sites according to topographical maps published by Canadian Energy Mines and Resources (available at any good map store). Equipped with the inventory and the maps, you can easily find the sites’ exact locations, even if the landfills have been closed for many years and the land has been developed.

A handy tool to help locate waste sites and to keep good notes on where you find pollution is a Geographic Positioning System (GPS). The inventory, topographical maps, and GPS coordinates all refer to the easily understood universal transverse mercator grid.

What to look for on-site

Landfill leachate is often rust coloured, but not always. It may even appear clear. Some of these discharges may be toxic, while others may be less harmful. In the case of old, improperly covered landfills, some solid wastes may poke through.

Landfill gases are more insidious. Their odour can cause discomfort and health problems, but you may have difficulty pinpointing their sources.

Contaminants to test for

Depending on the type of waste present at the site, the contaminants will vary greatly. But by looking at the waste disposal site inventory, you may be able to better define the analysis required. It is often useful to first do a wide-ranging reconnaissance scan for organics such as PCBs, dioxins, furans, and benzene-derived products, as well as heavy metals and ammonia. The analysis on the next series of samples need not be as extensive, depending on the results you obtain in your first scan. It may be appropriate to sample surface water, groundwater, and sediments.

Landfill gases consist mainly of methane and carbon dioxide but may also carry toxic chemicals (paints, solvents, pesticides) and toxic volatile organic compounds (VOCs). The following VOCs may be present: benzene, chlorinated solvents, chloroform, methylene chloride, tetrachloroethylene (PERC), toluene, trichloroethylene (TCE), vinyl chloride, and xylene.7

Acts and regulations that may apply

Fisheries Act

Ontario Water Resources Act

PCB regulations

Ontario Environmental Protection Act

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