Groundwater Sampling

Groundwater Sampling & Laboratory Testing​

A key piece of site characterization involves groundwater sampling and analysis. This process requires the installation of a monitoring well on-site. Our team of experts will arrange for public and private utility locates, and subcontract a licensed drilling company (in Ontario, O.Reg. 903), to drill and install one or more monitoring wells. AEL staff are on site to oversee drilling activities and often conduct high level screening. Monitoring wells are drilled deep into the ground to reach the groundwater and a slotted PVC pipe is installed, allowing groundwater to pass through it. Depth can vary greatly depending on the specific conditions of your site, but typically are between 5-20 metres. The length of this process can run anywhere from an hour to days and is also determined by site conditions, i.e., depth of monitoring well and type of material being drilled through.

Standard Procedures for Well Sampling

After installation is complete, the AEL team will gather samples according to specific sampling protocols. Water samples are then sent to a CALA-certified laboratory to be analyzed for a variety of parameters. The type of analysis is dependent upon your site-specific goals, and site conditions.

Samples are gathered to establish the quality of water and to obtain bacteriological information as part of a bioremediation program (if required). Special care must be taken to ensure that when a sample is collected from the well, it is only representative of one specific area. To avoid cross-contamination, we use dedicated samplers and tubing. Equipment is regularly sanitized and organized according to need. The AEL team is committed to using strict sampling and handling procedures in order to obtain the most accurate results for your site.

The Importance of Well Development in Groundwater Sampling

Well-development is required for proper sampling techniques and occurs after installation and before water sampling. In essence, well development involves pumping water from the well in order to retrieve well water samples that are truly representative of site conditions (e.g., free of drilling fluids, cuttings, or other materials introduced during well construction).

A representative water sample can be obtained when pH, temperature, and specific conductivity readings stabilize on the portable water quality checker. At this point, the water is generally visually clear of suspended solids. Our experienced team will typically purge a minimum of 3 well volumes, or until the well is dry. If a low-flow method of extraction is employed, purging is complete when readings from a water quality monitor are within 10% of each other (based on US EPA standards).

Quality Assurance and Control in Groundwater Sampling

AEL follows industry-standard Quality Assurance/Quality Control (QA/QC) procedures for groundwater sampling which include:

• Following detailed standard operating procedures and industry standards
• All samples are sampled directly into laboratory-prepared containers, pre-charged with preservatives by the laboratory where necessary.
• Field filtering is completed for metals analysis.
• As per O. Reg. 153/04, at least 1 duplicate sample is obtained per 10 samples taken.
• A trip blank, prepared by the laboratory, is submitted for analysis of Volatile Organic Compounds (VOCs), whenever VOCs are sampled.

AEL uses Canadian Association for Laboratory Accreditation Inc. (CALA) certified laboratories for all laboratory submissions.  The laboratory performs its own Quality Assurance/Quality Control (QA/QC) procedures and calculations, which are then carefully reviewed by our experts. In addition to these procedures, we perform calculations on duplicate samples to ensure that samples are truly representative and not influenced by any outside factors.