Transcript No Slide Title

Investigation of organic contaminants in the Medway and Seine estuaries
Objectives
1) To identify the nature and extent of Organochlorine (OCL)
contamination in surface & sub-surface sediments.
2) To identify the nature and extent of selected contemporary
herbicides in surface sediments.
3) To identify key priority organic pollutants for further study.
Introduction/Rationale
Sediment samples were collected from the Medway and Seine
estuaries in order to investigate organic contamination as part of
the Rives Manche Estuarine Watch (RIMEW) project. These
estuaries represent very different estuarine environments. The
Medway receives moderate contaminant inputs and has a low
sedimentation rate thus is sediment starved. In contrast, the
Seine is heavily contaminated as a result of its intense industrial
focus and is subject to high sedimentation rates and infilling.
• Contemporary herbicides under investigation are atrazine,
Irgarol, simazine, isoproturon, diuron and selected
metabolites. They are not as environmentally persistent as
their predecessors, but their enhanced solubility means that
they can easily reach surface and groundwaters.
MASE is a well-established sample preparation technique with
high recovery rapid extraction of the contemporary herbicides of
interest. Microwaves were first used in laboratories in 1975 for
the analysis of metals from biological samples and since then
many different methods have been developed for a variety of
samples. In 1986, Ganzler et al. used this technique to extract
organic compounds from solid matrices. Steinheimer 1993 used
this method to extract atrazine from soils and water samples
(Eskilsson and Bjorklund, 2000). LC/MSn has been recently
developed for the analysis of more soluble herbicides.
During this procedure sample is placed into a closed vessel with
a microwave absorbing solvent and irradiated with microwave
energy. The energy heats the solvent which is in contact with the
sample in order to partition analytes from the sample matrix into
the solvent (Eskilsson and Bjorklund, 2000).
England.
* Corresponding author
[email protected]
+44 (0) 20 7882 5573
Carey, P.J.
Centre for Contaminated Land Remediation
School of Science
University of Greenwich at Medway
Chatham Maritime
Kent
ME4 4TB
England.
• ASE offers opportunities for in-cell cleanup techniques.
• ASE considerably reduces solvent usage. Soxhlet extraction
can use from 250ml to 500ml of solvent.
• ASE reduces extraction times, a 10g soil sample can be
extracted in approximately 12 minutes using 15ml of solvent
(Dionex, application note 320).
• Sonication requires multiple washing procedure.
Although ASE has been used for the extraction of a range of
compounds from a variety of matrices (Bandh et al., 2000; Abrha
and Raghavan, 2000; Hubert et al., 2000; Gomez-Ariza et al.,
2002), its use on OCLs in estuarine sediments, with in-cell
sample clean up, has been more limited.
A comparison of ultra pure water with 1% methanol and 100%
methanol as extractants will be carried out to identify the most
efficient. Preliminary results suggest that matrix effects are
reducing extraction efficiency in the Medway sediment. Further
steps will investigate this issue.
50g (w/w) sample freeze-dried
ASE
OCLs were extracted from 20g (dry weight) sample under the following conditions:
Oven temperature = 100C; Pressure = 10 MPa (1500 psi); Oven Heat-up Time = 5 minutes;
Static Time = 5 minutes; Flush Volume = 60% of extraction cell volume; Solvent = Hexane
2 extraction cycles of hexane
In-cell alumina cleanup
20g of aluminium oxide (active basic) powder was put in the extraction cells, followed by a
Whatman 30mm filter paper and then the sample.
Each pair of extracts were combined and evaporated to 30ml using a TurboVap LV Evaporator.
Table 1: LC/MSn conditions
Solid Phase Extract (SPE)
HPLC
 Spark Holland Prospect2:  Agilent 1100 system
 High pressure
 Column:
dispenser (HPD)
 Supelco ABZ+ 25cm x
 Automated Cartridge
4.6mm, 5um particle
Exchange (ACE)
diameter
 Cartridges:
 Conditions:
 Hysphere C18 (End
 35% ACN:65% H2O
Capped) 8um
(0.1% HPLC grade
formic acid)
 10x2mm
MSn
 Agilent 1100 LC/MSD trap
 Atmospheric Pressure
Chemical Ionisation
(APCI) Source conditions:
 Nebulizer pressure =
50psi
 Dry gas flow = 5.0 l/min
 Dry gas temp = 325C
 Vaporiser temp = 400C
Post extraction sulphur cleanup
20g per sample of copper turnings were activated using a 5% nitric acid solution, rinsed with
deionised water until a neutral pH was obtained, acetone rinsed, allowed to dry and added in small
quantities to the samples until they no longer turned black.
Post extraction alumina cleanup
Aluminium oxide was activated by muffling at 500C and allowed to cool. 7%-deionised water
was evenly distributed by mixing and left overnight to equilibrate. Glass wool was used as a bung
in the columns, then 20g of activated alumina was tightly packed into the column using hexane
and 2-3mm of anhydrous sodium sulphate was added to the top. Samples were evaporated to 12ml and introduced to the column, then eluted through using hexane.
GC/MS
SIM Mode GC-MS and Large Volume Injection: The source = Electron Impact (EI); EM Voltage
= ATUNE; Syringe volume = 25ul; Injector volume = 50ul (injected as 4 x 12.5ul); Injection mode
= solvent vent; Injector programme = 50C for 1 minute then 720C/min to 300C; PTV liner =
multi-baffle, unpacked; Oven programme = 50(2)-20-200(0)-10-300(5.5) (Sandy, 2004).
Further work
• To continue method development for analysis of both OCLs
and contemporary herbicides.
• Analysis of Medway and Seine surface and core samples by
ASE method with the selected cleanup.
• Analysis of Medway and Seine surface samples by selected
MASE method.
Figure 4: Flow chart displaying the procedural steps used for
OCL pesticides.
Acknowledgements
•Results
The authors would like to thank Intereg II for funding this
research.
R2 = 0.999
References
6.00E+04
4.00E+04
2.00E+04
0.00E+00
0
10
20
30
40
50
60
Concentration (ppb)
•Abrha, Y. and Raghaven, D., 2000. Polychlorinated biphenyl (PCB) recovery from spiked
organic matrix using accelerated solvent extraction (ASE) and Soxhlet extraction. Journal of
hazardous materials, B80, 147-157.
•Bandh, C., Bjorklund, E., Mathiasson, L., Naf, C., Zebuhr,Y., 2000. Comparison of
Accelerated Solvent Extraction and Soxhlet Extraction for the determination of PCBs in Baltic
Sea sediments. Environmental science and technology, 34, 4995-5000.
•Canadian Council of Ministers of the Environment, 2002. Canadian Environmental Quality
Guidelines.
Isle of Grain
Kings North
E1 4NS
Canadian Marine ISQG
Motney Hill
London,
This study utilises a MARS 5 microwave with conditions based
on a method developed by Shen and Lee, 2003. An extraction
solvent of ultra pure water with 1% methanol is ramped to a
temperature of 95°C over 5 minutes then this is held for 3
minutes, with 80% output (maximum power of 1200W) and a
pressure of 200psi.
In this study alumina cleanup has been trialed both in-cell and
post-extraction to compare the recovery efficiencies of both.
Sulphur removal using copper tailings has been trialed as a postextraction cleanup to prevent reaction with the stainless steel
extraction cells.
8.00E+04
Akzo
Mile End Road,
SOURCE:http://www1.dionex.com/en-
1.00E+05
9.0
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
Queensborough
STW
Queen Mary, University of London,
Important progress has been made over the last decade in the
development of faster, safer and more environmentally friendly
extraction and cleanup techniques for preparation of
environmental samples for analysis (Lopez-Avila, 1999).
Traditionally pesticide extractions were performed using Soxhlet
extraction. Microwave Assisted Solvent Extraction (MASE),
Supercritical Fluid Extraction (SFE) and Ultrasonic Extraction are
alternative techniques that can be used. ASE also known as
Pressurised Fluid Extraction (PFE) is a procedure that uses
elevated pressures (1500 psi) and temperatures (100°C) to
extract water soluble semivolatile organic compounds from a
range of environmental media (USEPA, 1996). It has been
trialed in this study for the extraction of OCLs due to its
perceived advantages over alternative methods :
for contemporary herbicide extraction and analysis.
us/instruments/ins7387.html.
•Environment agency data for Endrin
Kemsley
Department of Geography,
Figure 3: Dionex ASE
200 system.
Lindane
Sittingbourne
STW
*Cutter, S. L., Heppell, C. M., and Spencer, K. L.
• Historical OCL Pesticides under investigation are aldrin,
dieldrin, DDT and its metabolites, endrin and lindane. They
are stable, environmentally persistent and damaging
pollutants.
Disadvantages:
• It uses a single extraction vessel, which needs to cool
before filtration this can cause re-adsorption issues (Smith,
2003).
• Microwave absorbing solvents required.
Faversham
STW
Accelerated Solvent Extraction (ASE) and Gas Chromatography/
Mass Spectrometry is being used in this study for the
investigation of historical organochlorine (OCL) contamination in
the Seine and Medway estuaries.
Advantages of MASE include:
• Multiple samples can be extracted simultaneously.
• Elevated Temperatures (Eskilsson and Bjorklund, 2000).
• Reduced extraction times (15-30 min) compared with
Soxhlet, Sonication and Supercritical Fluid Extraction (SFE)
(Jayaraman et al., 2000).
• Low solvent volumes (10-30ml), about 10 times smaller than
conventional techniques (Eskilsson and Bjorklund, 2000).
• More efficient than conventional techniques (Ganzler and
Salgo, 1986 in Shen and Lee, 2003).
Averaged site concentrations
(ug/kg)
Figure 1: Site locations. Cundy et al., 2004.
Microwave Assisted Solvent Extraction (MASE) - LCMSn
Microwave Assisted Solvent Extraction (MASE) and Liquid
Chromatography/Mass Spectrometry with online Solid Phase
Extraction (SPE-LC/MSn) is being used for the analysis of
contemporary herbicides.
Response
Overall aim
To investigate the nature and extent of organic contamination in
sediments from the Medway and Seine estuaries.
•Cundy, A. B., Hopkinson, L., Lafite, R., Spencers, K., Taylor, J.A., Ouddane, B., Heppell, C.
M., Carey, P. J., Charman, R., Shell, D. and Ullyott, S. Heavy metal distribution and
accumulation in two Spartina sp.-dominated macrotidal salt marshes from the Seine estuary
(France) and the Medway estuary (U.K.).
Site locations
Figure 2: Endrin concentrations in Medway estuary sediments
(g/kg) and the Marine Interim Sediment Quality Guideline
(ISQG) for endrin from the Canadian Environmental Quality
Guidelines.
Figure 5: Lindane mass spectra (insert: Lindane Calibration)
•Dionex. Extraction of Chlorinated Pesticides using Accelerated Solvent Extraction (ASE).
Application Note 320.
•Dionex, 1996. Selective extraction of PCBs from fish tissue using Accelerated Solvent
Extraction (ASE). Application Note 322.
•Eskilsson, C. S. and Bjorklund E., 2000. Analytical-scale microwave-assisted extraction.
Journal of Chromatography A, 902, 227-250.
Note from figure 2 that the average sediment concentrations of
Endrin at each site are above the Canadian ISQG. Due to these
high concentrations further investigation of such compounds is
necessary. None however exceed the Probable Effect Level
(PEL) of 62.4g/kg.
•Ganzler, K., Salgo, A., Valko, K., 1986. A novel sample preparation method for
chromatography. Journal of Chromatography A, 371, 299-306.
•Gomez-Ariza, J.L., Bujalance, M., Giraldez, I., Velasco, A., Morales, E., 2002. Determination
of polychlorinated biphenyls in biota samples using simultaneous pressurized liquid extraction
and purification. Journal of Chromatography A, 946, 209-219.
•Hubert, A., Wenzel, K., Manz, M., Weissflog, L., Engewald, W., Schuurmann, G., 2000. High
extraction efficiency for POPs in real contaminated soil samples using Accelerated Solvent
Extraction. Analytical Chemistry, 72, 6, 1294-1300.
•Jayaraman, S., Pruell, R. J., McKinney, R., 2000. Extraction of organic contaminants from
marine sediments and tissues using microwave energy. Chemosphere, 44, 181-191.
Accelerated Solvent Extraction (ASE) - GC/MS
for organochlorine pesticide extraction, cleanup and analysis.
A fully automated Dionex ASE 200 system has been used. This
system works by pumping a solvent into the top of an extraction
cell, which contains the sample and any in-cell cleanup options.
The cell is bought to elevated pressure and temperature within
the oven then the extract is forced out of the bottom of the cell
and collected in a vial for additional cleanup if necessary.
•Lopez-Avila, V., 1999. Sample preparation for environmental analysis. Critical Reviews in
Analytical Chemistry, 29, 3, 195-230.
Figure 6: 10ppb OCL mix standard in SIM mode.
The Seine surface samples contain high quantities of sulphur
and other co-eluting interference's, which means that cleanup
with copper turnings and alumina alone are not sufficient. Next
steps will examine an alumina:florisil mix cleanup.
•Sandy, C., 2004. Analysis of Organochlorine Pesticides and PCBs using SIM mode GC-MS
and Large-Volume Injection. Agilent Technologies UK Ltd.
•Shen, G. and Lee, H. K., 2003. Determination of triazines in soil by microwave-assisted
extraction followed by solid-phase microextraction and gas chromatography-mass
spectrometry. Journal of Chromatography A, 985, 167-174.
•Smith, R. M., 2003. Before the injection-modern methods of sample preparation for
separation techniques. Journal of Chromatography A, 1000, 3-27.