WHAT IS CHEMCATCHER

Chemcatcher® is a highly versatile and cost-effective passive sampling device for monitoring a wide variety of pollutants in potable, surface, coastal and marine waters.

It is now being used worldwide to help solve a number of water quality issues.

Chemcatcher® was developed through a number of projects funded by Framework Programmes of European Community by Professors Richard Greenwood and Graham Mills at the University of Portsmouth (UK) and Professor Greg Morrisonat the Chalmers University of Technology (Sweden).

HOW DOES CHEMCATCHER WORK?

The European Water Framework Directive has a ‘priority list’ of substances which pose a threat to or via the aquatic environment. The aim of this priority list is to reduce (or eliminate) pollution of surface water (rivers, lakes, estuaries and coastal waters) by the pollutants on the list.

However, there are also a number of emerging contaminants that are not included in routine monitoring programmes at EU level and whose fate, behaviour and (eco)toxicological effects are not well understood as yet. (http://www.norman-network.net/)

Typically Chemcatcher® measures the freely dissolved (sometimes called the biologically available fraction). Unlike spot samples, which only give a snapshot of the water quality at one moment in time, Chemcatcher® can provide time-weighted-average (TWA) and equilibrium concentrations over the deployment time, thus effectively concentrating the pollutants onto the receiving disk and lowering analytical detection limits.

  • Easy to deploy in the field

  • Cost effective as the PTFE body is reusable

  • Measures a wide range of pollutants

  • Validated by world-leading academics

  • Detect pollutants at low concentrations

  • Provides time-weighted average concentrations of chemicals

POLLUTANTS WE SAMPLE

Chemcatcher® for non-polar organic compounds

A popular application is the non-polar Chemcatcher. Recent applications include the measurement PAHs, PCBs, and specific pesticides. Performance reference compounds (PRCs) can be used to correct for any variations in environmental conditions (e.g. changes in water temperature and turbulence) during a field deployment. Such variations are then taken into account when estimating the TWA concentration during the exposure period.

Chemcatcher® for polar organic compounds

There has been recent interest in monitoring polar chemicals in water. This class includes polar pesticides (e.g. acid herbicides) and emerging pollutants such as pharmaceutical residues and personal care products. Two designs of Chemcatcher® are available to sequester these types of chemicals. Normally a diffusion-limiting membrane is employed also. Performance reference compounds (PRCs) cannot be used effectively with this version of Chemcatcher®.

Chemcatcher® for metaldehyde

Metaldehyde is a potent molluscicide and is the active ingredient in most formulated slug pellets. Large quantities of pellets are used in some agricultural areas at specific times in the year to control infestations in crops. As a consequence, often high concentrations of metaldehyde can found in surface waters after significant rainfall events. Chemcatcher® can be used to measure metaldehyde in water.

Chemcatcher® for metals

The Water Framework Directive (WFD) was introduced to achieve protection and sustainable development of water resources in the European Union (EU) countries through established Environmental Quality Standards (EQS). The directive sets annual averages and maximum allowable concentrations for inland and other surface waters for the dissolved fraction of some trace metals including nickel (Ni), cadmium (Cd), lead (Pb), zinc (Zn) and mercury (Hg) which are potentially quite toxic to aquatic life.

Applications include the measurement cadmium, copper, lead, mercury, nickel and zinc.

Chemcatcher® for organometallic compounds

This passive sampler device can be used to measure organotin compounds including: monobutyltin, dibutyltin, tributyltin (TBT) and triphenyltin.

Chemcatcher® for radionuclides

The Fukushima nuclear reactor incident in 2011 led to the release of large quantities of radioactive isotopes into the environment. Of particular concern was the impact of radio-caesium in different environmental compartments. Chemcatcher® has been shown to be effective in monitoring radio-caesium in contaminated water bodies. This work was undertaken by the Chiba Institute of Technology (Tokyo, Japan). Information obtained from using the device has helped to inform the environmental fate of radio-caesium and to assess the effectiveness of different remediation measures.

CUSTOMERS WHO USE CHEMCATCHER

CASE STUDIES

CASE STUDY 1

South West Water wanted improvements in raw water quality, through identification of tributaries that were sources of acid herbicides in the water.

Problem

  • Compounds such as mecoprop, MCPA, tricolpyr and clopyralid are widely used in South West England to control weeds in grassland.
  • Due to their high water solubility, this can lead to frequent run-off.
  • This in turn causes problems for South West Water as it is regularly detected in major drinking water catchments, above PCV level (0.1μg/l for a given pesticide). Indeed a single drop of MCPA in a water body like a stream of 1m wide, 0.30m deep, can be enough to exceed the legal limit for pesticides in drinking water of 0.1μg/l along 30km of its length. (1)

Solution

  • Chemcatcher passive samplers were chosen for monitoring as they avoid the ‘hit and miss’ nature of spot sampling.
  • Passive samplers can be deployed for extended periods (weeks) and can reveal time weighted average (TWA) concentrations of pollutants
  • The TWA concentrations were calculated and this allowed better estimates of the overall inputs of these herbicides into the catchment.
  • In addition, the samplers were able to detect sporadic inputs of these herbicides after rainfall events; these events were not picked up by spot water samples.

Source:

Mills G. A., Townsend, I., Jones, L., Broomb, M., Gravell, A. and Greenwood, R. (2016) Chemcatcher® for monitoring acidic herbicides in a river catchment in South West England [Oral Presentation] 8th International Passive sampling Workshop and Symposium. Prague. 7-10 September.

CASE STUDY 2

United Utilities used Chemcatchers at 13 sites across the Dee catchment, to measure metaldehyde and different acid herbicides at each site was to better understand the concentration of pesticides in the river water over continued periods of time (spot samples can often miss pesticide spikes) and also to assess the spatial characteristics of pesticide application across the catchment.

These herbicides included:

  • MCPA
  • 2,4-D
  • Clopyralid
  • Mecoprop
  • Fluroxypyr
  • Triclopyr
  • Dicamba
  • Bromoxynil
  • Bentazone
  • Metaldehyde

Problem

  • Seasonal variation of pesticides occurs during the year, e.g. MCPA had a relatively high average concentration in the catchments during the spring and summer months, while autumn and winter measurements were low.

Solution

  • With the Chemcatchers, United Utilities was able to identify particular problem areas with two areas identified as being particularly problematic, with high amounts of 2,4-D and MCPA in the late spring/early summer. Other pesticides, such as clopyralid and fluroxypyr, were present consistently at lower levels for many sub-catchments all year round.
  • The data provided by the Chemcatchers helped United Utilities to prioritise the sub-catchments according to how much of a risk they present to drinking water quality.

Source:

United Utilities (2017) River Dee Catchment Using Data and Evidence to Target

Water Quality Measures Westcountry Rivers Trust. Available at: http://www.welshdeetrust.com/wp-content/uploads/2017/10/UU_Dee_Catchment_Report_11-09-17_WEB-MEDIUM-2.pdf [Accessed 11 April 2018]

CASE STUDY 3

Following a major earthquake, a 15-metre tsunami disabled the power supply and cooling of three Fukushima Daiichi reactors, causing a nuclear accident on 11 March 2011. The accident was rated 7 on the INES scale, due to high radioactive releases over days 4 to 6, eventually a total of some 940 PBq (I-131 eq) (2).

Problem

  • The main radionuclide which was emitted due to the accident was caesium-137, which has a 30-year half-life, is easily carried in a plume, and when it lands it may contaminate land for some time. It is a strong gamma-emitter in its decay.
  • Cs-134 is also produced and dispersed, it has a two-year half-life.
  • Caesium is soluble and can be taken into the body, but does not concentrate in any particular organs, and has a biological half-life of about 70 days. (2).

Solutions

  • Collaborations with Chiba Institute of Technology, Japan and 3M Tokyo resulted in a modified Chemcatcher, suitable for monitoring radio-caesium in waters near the Fukushima reactor.
  • A bespoke receiving phase with a high affinity for Caesium allows time integrative accumulation and lowers detection limits.
  • Removes the need to collect of large volumes (c. 200 L) of potentially radioactive water.

Source: Research Excellence Framework (REF) 2014 Impact Case Studies. (2014) The Chemcatcher – an approved passive sampler for monitoring water quality. Available at: URL [http://impact.ref.ac.uk/CaseStudies/CaseStudy.aspx?Id=14991 [Accessed 11 April 2018].

ABOUT T.E LABORATORIES

T.E. Laboratories Ltd is a unique SME which has continued to expand and diversify over its 25-year history in Tullow, Co. Carlow, Ireland.  The company’s ability to attract a highly skilled and educated workforce of engineers, scientists, chemists and professionals has resulted in the company leading several industry sectors in research, design and innovation through chemistry, engineering and academic research.

T.E.Laboratories was formed in 1991 initially specializing in the analysis and treatment of fuel.

Since then the company has gone from strength to strength through a series of diversifications of our core business.

We now boast a first-class INAB Accredited Environmental Laboratory, a Chemical Manufacturing Laboratory, and a Microbiological Laboratory in addition to our Fuel Laboratory.

ABOUT T.E LABORATORIES

T.E. Laboratories Ltd is a unique SME which has continued to expand and diversify over its 25-year history in Tullow, Co. Carlow, Ireland.  The company’s ability to attract a highly skilled and educated workforce of engineers, scientists, chemists and professionals has resulted in the company leading several industry sectors in research, design and innovation through chemistry, engineering and academic research.

T.E.Laboratories was formed in 1991 initially specializing in the analysis and treatment of fuel.

Since then the company has gone from strength to strength through a series of diversifications of our core business.

We now boast a first-class INAB Accredited Environmental Laboratory, a Chemical Manufacturing Laboratory, and a Microbiological Laboratory in addition to our Fuel Laboratory.

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