Landfill Groundwater Monitoring
Environmental impacts from a landfill are not caused by the amount of garbage it receives. Instead, the impacts are largely due to being in a location with unsuitable site conditions and inadequate design, construction and operation. Landfill activities can impact the groundwater, surface water, soils and surrounding land.
The precipitation that falls onto a landfill, along with any disposed liquid waste, results in the creation of leachate which contains water soluble contaminants from the waste such as dissolved metals, salts, and other contaminants of concern. The leachate can impact the groundwater and present risks to human health and the environment. Depending on the site geology and hydrogeology the leachate can migrate off site and impact aquifers and/or surface water.
The Ministry of Environment requires groundwater monitoring at landfills to understand if leachate impacts are occurring, if they are impacting adjacent properties, and if any receptors, such as potable water sources, are at risk.
The ministry has heard concerns that the cost of groundwater monitoring at landfills is a burden. There are options to assist communities in reducing groundwater monitoring costs.
Groundwater sampling
There are many landfills that reduce monitoring costs by taking their own groundwater samples. The ministry requires that the landfill has documented procedures in place to ensure that samples are collected, preserved, stored, handled and analyzed in accordance with a method approved by a standards-setting organization. Procedures need to include quality assurance/quality control procedures, and staff need to be trained in sampling protocols and procedures. It is very easy to contaminate a sample, so it is important that procedures are followed.
The ministry requires that summary of the monitoring be included in the groundwater report which includes, but is not limited to, a description of the following:
- Monitoring and sampling equipment used to determine the depth to groundwater and to obtain groundwater samples (e.g., water level indicator, pump, tubing, water-quality indicator parameter meter, decontamination supplies, sample bottles and preservation supplies);
- Groundwater purging procedure (e.g., well volumes removed, parameter stabilization procedure);
- Groundwater sampling procedure;
- Equipment decontamination procedure; and
- Quality control procedures (e.g., equipment and trip blanks, duplicate samples, etc.).
A qualified person is required to write the monitoring report and provide interpretation of the results. It is important for the report to include information on contaminant trends and potential impacts to receptors.
If your community would like procedures and training to take your own groundwater samples, the ministry recommends contacting a consultant for more information. There are many landfills that have had consultants provide procedures and training.
Groundwater monitoring frequency
The ministry is working to reduce groundwater monitoring frequency at low-risk operating landfills and closed landfills. Environmental Protection Officers are determining when it is appropriate to reduce monitoring frequency when they review groundwater monitoring reports. The decision is based on how long a landfill has been monitoring, the monitoring results, trends in contaminant concentrations, and site-specific factors such as soil conditions and location of receptors such as groundwater wells, rivers, etc.
Please reach out to the ministry if you would like to discuss taking groundwater samples, reducing the frequency of groundwater monitoring, or the monitoring program in general. You can contact an Environmental Protection Officer by contacting the Client Service Office at 1-800-567-4224 or email centre.inquiry@gov.sk.ca.