the many faces of the chemcatcher® passive …the many faces of the chemcatcher® passive sampler...

The many faces of the Chemcatcher® passive sampler

Adil Bakir a, Gary Fones a and Graham Mills b

aSchool of Earth and Environmental Sciences, University of Portsmouth

b School of Pharmacy and Biomedical Sciences, University of Portsmouth

Chemcatcher® - a cost effective passive sampler

• Monitoring the concentration of chemicals in water is statutory requirement across Europe e.g. Water Framework Directive (WFD) (Council Directive 2000/60/EC – 2000)

• Within the WFD, Environmental Quality Standards or EQSs are used for

assessing the state of the water environment through classification, and are used as the fundamental measurement in the water quality monitoring programmes.

• EQSs tell us the quantity of a chemical pollutant that can “safely” be present in the water body without causing harm to the ecology and ideally that presents no significant risk to human health.

• National environment agencies in Europe have a legal obligation to ensure that the

statutory EQSs are being met. • EQS are defined as both the maximum and average permissible concentration of a

potentially hazardous chemical in an environmental sample (usually in terms of μg L-1, ng L-1 or pg L-1).

Chemcatcher® - Visual Perspective – Tributyltin EQS

For tributyltin EQS of 0.2 ng L-1

1 drop (20 μL) in 20x Olympic sized swimming pools

For cypermethrin EQS of 0.008 ng L-1

Analytical challenges


• Most monitoring programmes involve the periodic collection of low volume spot samples of water (bottle or grab) that are analysed subsequently in the laboratory

• Passive samplers can effectively concentrate pollutants compared to spot sampling –

lower analytical detection limits

• Passive samplers can provide time-weighted-average (TWA) and equilibrium concentrations over the deployment time, rather than a snap shot at one moment

Use of passive samplers (cont.)

The versatility of the Chemcatcher® passive sampler

Chemcatcher® – University of Portsmouth

UoP Chemcatcher’s website and on-line store

http://www.port.ac.uk/research/chemcatcher/

UoP Chemcatcher’s website and on-line store




Chemcatcher® – University of Portsmouth

Chemcatcher® passive sampler

Chemcatcher® – Qualitative assessment

• “Screening” mode for the presence or absence of compounds

• Usually used as a “detective work” to pinpoint sources of pollution

• “Upstream thinking” initiative (South West Water) to improve water quality in river catchments in order to reduce water treatment costs.

Chemcatcher® – Semi-quantitative and quantitative assessment

• Also can be used as a “detective work” to pinpoint sources of pollution

• Allows quantification of target compounds

• Requires calibration of the Chemcatcher® under laboratory conditions:

Laboratory set-up of the passive samplers on the carousel

Passive sampler uptake profile

Sampling Rate (Rs) derived from this gradient.

Passive sampler uptake profile

Calibration of the Chematchers under laboratory conditions

Passive sampler uptake profile for metaldehyde (Ci = 1 mg L-1)

Time weighted average concentration

Time weighted average (TWA) concentrations (CW in ng L-1) can be derived from a simple equation:

where: MS = mass of pollutant on Chemcatcher disk (ng) M0 = mass of pollutant on field blank Chemcatcher disk (ng) RS = sampling rate of pollutant (L day-1) t = Chemcatcher deployment period (days)

Deployment and retrieval of Chemcatcher

Sampling cage (lid removed)

Cage lid with Chemcatchers attached

Cage after two week deployment

Deployment of the Chemcatchers on site

The versatility of the Chemcatcher® passive sampler

Metaldehyde Chematcher®

• Molluscicide widely used on cereals and Oilseed Rape

• Very stable, high solubility and mobile in the environment

• Hard to remove from water even using advanced treatment processes

• Has frequently exceeded 0.1 µg L-1 PCV in treated water since monitoring began in mid-2000s.

• NERC funded PhD project was initiated at UoP in 2014

R.I.P.

Polar organics Chemcatcher®

• Monitoring polar pesticides, pharmaceutical residues and associated metabolites and personal care products together with their degradation products.

• Several designs of Chemcatcher® are currently being used to

sequester these types of chemicals.

• Moschet et al. (2014) used a Empore™ SDB-RPS receiving phase in conjunction with a polyethersulphone membrane for an in-situ calibration of the Chemcatcher® for 322 polar pollutants [1]

• For the majority of the substances there was a good correlation

between those detected in water samples with those found on the receiving disks.

[1] Moschet et al. (2014) Water Research 7 1 306-317

Polar organics Chemcatcher® (cont.)

Non-polar organics Chemcatcher®

• This sampler uses a C18 Empore™ disk overlaid with a thin low-density polyethylene membrane.

• In order to increase the uptake rate of analytes a small quantity of n-octanol is added between these layers during manufacture.

• Recent applications of the device include the measurement PCBs, PAHs and DDT [2, 3]

• Using the same receiving phase with a cellulose acetate membrane the Chemcatcher® can

measure organotin compounds including monobutyltin, dibutyltin, tributyltin (TBT) and triphenyltin [4]

[2] Petersen et al. (2015) Environmental Science: Water Research & Technology, 218-226. [3] LOBPREIS, T. et al. (.2010) Acta Chimica Slovaca, 3, 81-94. [4] Aguilar- Martínez et al. (2008)

Non-polar organics Chemcatcher®

• This sampler uses a C18 Empore™ disk overlaid with a thin low-density polyethylene membrane.

• In order to increase the uptake rate of analytes a small quantity of n-octanol is added between these layers during manufacture.

• Recent applications of the device include the measurement PCBs, PAHs and DDT [2, 3]

• Using the same receiving phase with a cellulose acetate membrane the Chemcatcher® can

measure organotin compounds including monobutyltin, dibutyltin, tributyltin (TBT) and triphenyltin [4]

[2] Petersen et al. (2015) Environmental Science: Water Research & Technology, 218-226. [3] LOBPREIS, T. et al. (.2010) Acta Chimica Slovaca, 3, 81-94. [4] Aguilar- Martínez et al. (2008)

Table 2 Uptake rates Rs (L day-1) estimated by Petersen et al. (2015), Cw measured during the experiments and value of slopes and p-values of the linear regression curves of the test substances (The standard deviations are given in the respective ± columns)

Tap w

ater

Seaw

ater

Metals Chemcatcher®

• Metals in water can be sequestered using a Chemcatcher® fitted with an Empore™ chelating disk.

• The performance of the device was investigated in relation to its application in regulatory monitoring (e.g. European Union’s Water Framework Directive) of trace metals (e.g. Cd, Cu, Ni, Pb and Zn) in surface waters [5].

• The responsiveness of the sampler was evaluated for rapidly changing aqueous concentrations of metals and clearly demonstrated its ability to react to transient pollution events

[5] Allan et al. (2007) Journal of Environmental Monitoring, 9, 672-681.

Table 1. Uptake rate of metals for the Chemcatcher® passive sampler [5]

Exposure conditions

Velocity = 70 cm s-1

Temperature = 18°C

Uptake rates (RS) of metals for the Chemcatcher® sampler (L day-1)

Cd Cu Ni Pb Zn

Mean 0.12 0.12 0.14 0.02 0.13

Standard deviation of Rs (%) 12 10 7 13 10

Radionuclides Chemcatcher®

• The Fukushima nuclear reactor incident in 2011 led to the large release of radioisotopes into the environment

• Of particular concern was impact of radio-caesium in different environment compartments

• A commercially available ceasium RAD-disk was avaialble from 3M as part of their Empore™ range.

• The University of Portsmouth teamed up with the Chiba Institute of Technology , Tokyo

and 3M Japan to investigate the use of this product as a receiving phase for Chemcatcher®.

• High affinity for Caesium enabling time integrative accumulation and lower detection limits.

• No need to collect large spot samples of potential radioactive water (~ 200 L)

• Various agencies in Japan have been undertaken to investigate the environmental fate of radio-caesium and assess the effectiveness of different remediation measures.

Nutrients Chemcatcher®

• A recent addition to the family of devices is the development of a version for monitoring nutrients such as nitrate and phosphate [6]

• Here the sampler is fitted with an Empore™ anion-SR disk overlaid with a cellulose acetate membrane.

• The device was shown to selectively sample labile nitrate and phosphate species being confirmed by comparison of the analysis of spot samples using ion chromatography.

[6] Knutsson et al., 2013.

Fig. 2 Calibration curves for nitrate and phosphate at pH 7.0, 14°C, 200 rpm and concentration of 2 mg L-1 nitrate and 1mg L-1 phosphate [5]

Limitations and on-going work

Biofouling – we are currently working on new materials to overcome this limitation

Thank you for your attention!


[email protected]

chemcatcher @chemcatcher


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ISO standard

Development of a global (ISO standard) by Prof Richard Greenwood

National and International Impact

On-going projects related to Chemcatcher®

the many faces of the chemcatcher® passive …the many faces of the chemcatcher® passive sampler...

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