Why Choose Chemcatcher®
Chemcatcher® is a passive sampling device, capable of monitoring ultra-trace micropollutants in surface water, groundwater and coastal water monitoring applications. It has many advantages compared with traditional grab or spot sampling, biota, and, indeed, other forms of passive sampling.
- Chemcatcher® is an extremely cost-effective way of monitoring what is happening in an aquatic environment over time, with no power, maintenance or supervision requirements. The only manpower inputs required over the study period are for initial deployment and retrieval for analysis.
- With typical deployments of 7 days to a fortnight, it is capable of capturing sporadic, transient inputs of pollutants and fluctuations in levels over time, which are easily missed with spot analysis. An accurate, time-weighted average can be calculated for the deployment period.
- Chemcatcher® is capable of detecting problematic compounds even at very low levels, beyond what is often possible with conventional spot sampling.
- Typically, the amount of chemical accumulated by the device reflects the freely dissolved and labile fraction that is most readily bioavailable, thus providing a more accurate indication of impact on the ecosystem.
- Chemcatcher® is a highly versatile system. Different combinations of the membrane and receiving phase enable screening for the vast majority of problematic aquatic micro-pollutants, including both polar and non-polar organic compounds such as PAHs, PCBs, PBDEs, pharmaceuticals, pesticides, as well as radionuclides, trace metals, metalloids and organometallic compounds.
Advantages compared with grab or spot sampling
- The conventional approach to water quality monitoring – collecting samples in bottles and bringing them back to the laboratory for analysis – is very expensive and time consuming. Likewise, automated samplers can be expensive, vulnerable to theft or vandalism, and require maintenance, and, again, laboratory analysis costs can be significant.
- Spot sampling is also severely limited in the information it provides. It simply reveals the level of pollution at the particular time of sampling. In real-life aquatic environments, concentrations vary over time, due to sporadic effluent discharges, tidal impacts, rainfall variations and so on.
- For some priority substances, environmental quality standards (EQS) demand detection at extremely low levels, particularly in marine environments. When contaminants are present at such low levels, with spot sampling, it may be necessary to collect large volumes of water and concentrate the sample prior to analysis to reach detectable levels, making the process more expensive and highly cumbersome.
Advantages compared with biota
- Certain substances, targeted for monitoring under environmental legislation, accumulate within aquatic species, such as fish, allowing biota monitoring to be used to detect environmentally relevant concentrations of lipophilic substances, and, as accumulation represents exposure over time, this can provide a time-weighted representation.
- However, in practice, there are a number of difficulties associated with biota monitoring. For instance, there can be challenges finding the correct species, size range, age, etc at a given location. In extreme cases, poor water quality conditions may make it impossible for the targeted species to survive. Furthermore, issues such as metabolism and intraspecies biological variability can further cloud the comparability of results.
- In contrast, with Chemcatcher® the results are site specific; samples are easier to extract and potential problems associated with metabolism are eliminated.
Benefits compared with other passive samplers
- Chemcatcher® can detect both polar and non-polar compounds, extending its applications.
- Because it uses a disk as opposed to beads, there is increased absorption across the whole of the disk.
- The larger surface area provides improved performance for the detection of pharmceuticals and pesticides.
- The Chemcatcher® casing is re-usable, allowing the user to move away from single-use plastic and providing better value for money in cases where multiple deployments will be required.