Passive and High Volume Sampling
Passive Sampling devices typically collect dissolved contaminants from aqueous environments and can be deployed in the field for weeks or months to produce a time-averaged estimate. The use of performance reference compounds (PRCs), especially for non-polar contaminants, enables the conversion of the amount measured on the sampler into a water concentration. Passive samplers such as polyethylene (PE) can also be deployed in sediment to estimate pore-water concentrations which are more representative of bioavailability than bulk sediment concentrations.
SGS AXYS offers preparation, extraction and analysis of an extensive list of organic compound passive samplers including Semi-Permeable Membrane Devices (SPMDs), Polyethylene Devices (PEDs), POM (polyoxymethylene), silicone strips and Polar Organic Chemical Integrative Sampling disks (POCIS). See our table below for a comprehensive list.
High Volume Water Sampling
SGS AXYS uses XAD-2 solid phase extraction and to extract high volume samples as large as 60L, thus enabling achievement of ultra-low detection limits in aqueous samples. This procedure includes a filtration step allowing separate analysis of particulate and dissolved phase contaminants. We routinely apply these procedures in support of regional monitoring, Total Maximum Daily Loads (TMDL) studies and risk assessments processes. We supply proofed XAD-2 resin columns and filter cartridges for use in field sampling with equipment such as the Infiltrex 300 Sampling System, or apply this technique in-house on samples shipped to the lab in 20 L canisters which we clean and proof before shipping. SGS AXYS also supports other high-volume water sample collection technologies such as Continuous Low-Level Aquatic Monitoring ( C.L.A.M. ) samplers or PUF tubes.
Environmental Canada scientists (Mundy et al., 2019) used an innovative approach with SPMD extracts to collect the complex oil sands mixture in the field and make it available for lab-based in-vitro testing. SGS AXYS provided the measurement for a suite of 75 parent and alkylated Polycyclic Aromatic Compounds (PACs) in the SPMD. This measurement goes well beyond the usual set of 18 or so PACs routinely monitored for health effects. Sites with higher PAC concentrations had the most gene alteration, and higher levels of oxidative stress. Passive sampling is great for this kind of study as it provides a representative, time-averaged sample for exposure testing rather than a time-snapshot water sample