Introducing the Sorbisense passive sampling technique

July 8, 2013

Sorbisense is a European passive sampling system that can provide better and more reliable water quality data for decision making, potentially at a lower overall cost than more traditional methods of groundwater sampling. Sorbisense technology is based on advanced adsorbents, designed to retain specific chemical groups or solutes like concentrations of nitrate, phosphorous, pesticides, oil and tar components, heavy metals and Volatile Organic Compounds.

SORBICELL

The Sorbisense system comprises of a SorbiCell, a small cartridge containing the adsorbent and a tracer salt. When installed, water slowly passes through the porous SorbiCell at a controlled rate. The adsorbent has a high capacity, enabling retention and accumulation of solutes from the passing water during the entire installation period. The tracer is dissolved proportionally as water transits the SorbiCell so the accurate volume of water is known.  At the end of the monitoring period the cartridge is easily extracted and sent to a laboratory for analysis. The analysis of the sample will also give a flow proportional measurement (mass/volume or mg/l), giving a “history” of what is happening over the deployment period.

Sorbisense systems can supplement or replace traditional sampling methods for groundwater, drinking water, agricultural effluents, fish farming, wastewater treatment plants, industrial wastewater, drains, lakes, ponds or streams. Passive sampling can provide substantial cost savings and there is much research in the United States, mainly led by the Department of Defence (DOD) that cost reductions of 40-60% are not uncommon. In addition passive sampling makes monitoring events very consistent because they are virtually independent of the user.

The Sorbisense system is suitable for:

– Screening and risk evaluations

– Evaluation of in situ remediation

– Environmental research

– Groundwater monitoring

– Monitoring drinking water quality

– Monitoring drainage water, lakes and ponds

– Industrial wastewater monitoring

– Green technology.

A Sorbisense sampler is typically installed from 1-2 weeks up to 3 months and, like the cartridges and mounting options used, will depend on the project. The tracer compounds within the SorbiCell are moderate to low soluble salts that are completely harmless to the environment.  And our tracer compounds are hardly affected by ionic strength and pH normally encountered in groundwater and freshwater.  In more saline conditions, we recommend a separate volume calibration.

The detection limit of Sorbisense compared to more conventional liquid samples depends on the smallest amount that can be detected on the resin, and the volume of water passing the sampler. For sampling VOCs in groundwater, the detection limit is somewhat higher than for other contaminants in water samples. For other compounds, the detection limits are comparable to levels reported for water samples. To obtain a good measurement, it is essential that the sampled water volume is in the optimal range.

Sorbisense systems are simple to install, can save time and money and offer repeatable,  accurate water quality monitoring results. They are very suitable for the passive groundwater sampling of VOCs, metals and nutrients.

Van Walt is the exclusive distributor of Sorbisense® in the UK and Ireland. Visit https://www.vanwalt.com/no-purge-sampling-adsorption.html for more information.