Contamination of land and water can occur for a variety of reasons and from a variety of sources. Activities such as the operation of a fuelling site, salt storage for roadway maintenance, fire suppression and waste disposal are all activities which could result in environmental contamination. Sites operated in the past, when environmental concerns were not well understood or recognized, are often at risk for contamination. Sites constructed now are usually engineered to manage potential contaminant sources to prevent pollution of the environment.
Not all contaminants pose a risk to human health. Each contaminant listed in the Tier 1 and Tier 2 Soil and Groundwater Remediation Guidelines published by Alberta Environment and Protected Areas poses different risks to each receptor category in the guidelines. Receptors are the organisms that may be affected by the contaminants, for example freshwater aquatic organisms, agricultural plants, or people. Contaminants are evaluated for their harm to the receptor including effects such as human health, fish mortality and even soil structure. Not all contaminants are harmful to human health. Those that are harmful to human health do not always fall into the category of toxins, poisons or carcinogens.
Most contaminants are not considered ‘hazardous.’ Hazardous waste is defined through legislation and regulation in Alberta. There are specific requirements for the management of hazardous waste. Typically, environmental contamination is not found in concentrations that would be considered hazardous waste.