A Passive Revolution In Water Sampling
From spot-checking to continuous environmental monitoring
Traditional water-sampling techniques are complicated, time-consuming, and often expensive. Worst of all, they provide either only snapshots of pollution events or need expensive sampling stations that require electricity and servicing. Eurofins Sorbisense came up with a unique alternative.
Eurofins’ ground-breaking Sorbisense™ passive sampling system is designed to ease groundwater and surface water contamination assessment, and provide better and more reliable water-quality testing data.
SorbiSystems™ comprises a small cartridge, the SorbiCell, which contains an adsorbent and a tracer salt. SorbiSystems™ is suitable for installation in groundwater, surface water and wastewater environments. Once installed, water passes through the unit at a controlled rate, retaining the accumulation of specific chemical groups and solutes such as pesticides, nitrate, and volatile organic compounds. These solutes are collected throughout the entire installation period of the sampling cartridge.
As water moves through the unit, the tracer is dissolved proportionally to volume, regardless of the sampling rate. This principle allows a very accurate measurement of the sample volume and solute mass concentration. The cartridge is then easily removed and sent to a laboratory for analysis.
Data obtained through SorbiSystems™ represent an accumulated average concentration rather than a single snapshot, providing significantly more consistency of results and enabling an exact assessment of risks and the effect of remediation.
The technology can be used to assess groundwater, drains, drinking water, lakes, ponds and streams, and industrial wastewater. It has particular appeal for companies in sectors like aviation, oil and gas, and utilities where security issues and access to sites can be a challenge. Efficient for all types of risk screening and risk assessments, the system is estimated to save 50-80% of the previously required time in the field.
In another example of Group innovation in water sampling, Eurofins is the first laboratory network to make the POM (polyoxymethylene) passive sampling technology commercially available in Europe. Developed by the Norwegian Geological Institute, POM is a passive sampling method which can be used to monitor organic contaminants such as PAH and PCB in water.
Thin strips of the polymer polyoxymethylene are fixed to ropes or other sampling gear and deployed from an anchor line to monitor fresh water, sea water, wastewater, groundwater and pore water, across various applications, over a four week period or longer. POM sampling is simple to use, does not require special deployment of a field cage and avoids sample contamination or saturation.
The science behind
The Sorbisense™ sampling tool is suitable for sampling virtually all chemical solutes (contaminants). No equilibrium-based assumptions are made, and no diffusion calibrations required, just direct and transparent volume-based calculations of solute concentrations. Specially-designed mounting units allow for easy installation in a wide range of water environments.
POM is an equilibrium passive sampler where strips of polyoxymethylene are submerged in water, via an anchor line or placed in an underwater sediment bed via an aluminum frame. The POM strips monitor for organic contaminants in water over a period of four weeks or more. The state of equilibrium that the strips achieve during this time allows for the concentration in the water to be calculated, and extremely low concentrations of PAHs and PCBs can be detected. The detection limit can be as low as 1 pg/l for PCB and 1 ng/l for PAH. The testing method does not require any information on the salinity, temperature, water velocity or viscosity of the sample.