13th EAOG Newsletter, Autumn 2001
1. Newsletter Editor's bit
Dear readers, this is last time I compile the EAOG Newsletter, since I
will be taking over as Chairman after the next board meeting in early
2002. I hope you have enjoyed the 9 newsletters I have put together
over the last 5 years. Thanks to those of you who have contributed
directly to them, and for your (generally appreciative) comments on my
efforts. You will - for better or worse - be hearing from me again in my
new role, so it is not goodbye but "au revoir".
In this newsletter you will find a summary of the minutes from the last
board meeting in Nancy, information about the EAOG web site, and travel
reports from Marie Russell and Manuel Algarra González, as well as some
parting thoughts from our dear Chairman. I hope you find it interesting.
Best wishes
Richard Patience.
2. Parting message from the Chairman
And so the day has finally come when I must hang up whatever it is that
EAOG Chairmen hang up at the end of their term of office. Actually, I
will continue to serve until early in 2002, but as far as the Newsletter
is concerned, this is it, my last offering.
I have enjoyed being EAOG Chairman. First and foremost let me thank the
organisation and membership for giving me the opportunity to make my
mark. It was certainly an honour to follow in the footsteps of my mighty
predecessors Pieter Schenck and Geoff Eglinton. I have tried to maintain
the traditions and ideals which they helped establish because ultimately
it is this that sets EAOG aside from all other organisations. The
travelling road-show format of IMOG meetings, each venue with its own
peculiarities, is one of these. On the other hand, we have seen the
switchover to a more business-orientated running of the organisation
with each Board member having a specific duty; voting procedures have
been streamlined too. We have expanded our conference activities beyond
IMOG, to include, possibly for the first time this year, the
co-sponsoring (albeit in name only) of the Goldschmidt Conference. The
EAOG Awards programme has flourished, especially the Travel Award which
has seen a dramatic increase in the number of young scientists using
this $-vehicle to enable them to spend time in other academic
institutions. Membership is at an all time high, so perhaps now is the
best time to leave after all.
I shall be passing the baton on to Richard Patience. Richard will make a
good chairman I think, because he is dynamic, open to new ideas and is
not afraid of speaking his mind (did I say this was an advantage?). It
was on consideration of these qualities that he was elected to the post
by his Norwegian, Dutch, French, German and British colleagues on the
Board. Why raise the issue of nationality? Because Richard himself was
acutely aware that he would be the third Britain in a row to get the
job, and thought other nationalities should get their chance. Next time.
I wish Richard all the best.
In closing I want to extend my warmest congratulations to Archie
Douglas, co-opted EAOG Board Member and Scottish philanthropist, who was
recently awarded the prestigious Treibs Medal by The Geochemical
Society. While one interpretation is that "the Committee must have been
at the bottle" (Douglas, personal communication), another is that he
actually deserved it. In short, they recognised the immense impact he
and his group at Newcastle has had on organic geochemistry in a career
which spans more than forty years. Well done, Arch !
3. Minutes of the EAOG Board Meeting
Palais des Congrès, Nancy, September 10th 2001
Board members attending the meeting were Derenne, Douglas, van Graas,
Horsfield (Chairman), Michaelis, Patience, Rowland, Telnaes. Maciej
Kotarba (University of Krakow) and Artur Stankiewicz (Shell) attended
the part of the meeting dedicated to the presentation of the next IMOG.
Friso Veenstra (Elsevier) and Joe Curiale (Organic Geochemistry
editor-in-chief) were present until the end of item 4 and James Maxwell
(University of Bristol and future co-opted member replacing Douglas)
attended the whole meeting.
Item 1 : Welcome
The chairman opened the discussion at 6:40 p.m. He welcomed the board
members and the guests.
Item 2 : Minutes
The minutes of the last board meeting were unanimously approved.
Item 3 : Presentation of the next IMOG in Krakow (M. Kotarba and A.
Stankiewicz)
Kotarba thanked the board for giving him the opportunity to organize the
next IMOG in Krakow in September 8-12th, 2003. He also thanked Artur
Stankiewicz who suggested a few years ago to have the meeting organized
in Poland and Joe Curiale for his encouragement. He showed the logo for
the 21st IMOG which shows the Royal Castle of Krakow. He mentioned that
although Warsaw is the official capital of Poland, Krakow is the
intellectual and cultural capital. Indeed, 20 universities with more
than 80,000 students are present in Krakow among which the oldest
European university. Kotarba presented himself and was proud to say that
the President of the Republic of Poland will be Honorary president of
the next IMOG. Kotarba will be chairman and Stankiewicz vice-chairman,
responsible for the scientific program and committee. The local
committee is mainly composed of members from Kotarba's group.
Stankiewicz showed slides of the proposed conference venue (Conference
and Sport Centre) which comprises a poster hall designed to hold 200
posters and various rooms with capacity ranging from 50 to 250 persons.
For a higher capacity, it is planned to convert one or two basketball
court(s) into conference room(s). An alternative to this conference
venue was mentioned, a conference building which should be built in
2002. Concerning the financial part, the board members asked the
organizers to maintain the fees at the level of Nancy and stressed the
importance of sponsorship. The organizers already have the financial
report of the Istanbul meeting for guidance and that of Nancy will be
provided later. Price ranges for hotels located in the vicinity of the
conference centre were given as well as that of student dormitories. The
places chosen for the ice-breaker party (Royal Castle at Wawel Hill),
the opening ceremony (Slowacki Theatre) and the conference dinner (old
salt mine, 15 km from Krakow) were described along with the pre- and
post-conference trips (raft trip in the Pieniny Mounts and cable car
climbing to Kasprowy Wierch for the former and Eastern Carpatians for
the latter). The accompanying person program is not yet prepared and
will be presented to the board at the next board meeting in January
2002. Krakow access was presented : the international airport of Krakow
has direct connections with most European capitals and with Chicago.
Moreover, Krakow is 2.5 hours from Warsaw by train.
The board members asked the organizers to give to the website officer a
CD Rom with all the above information for the EAOG website.
Item 4 : Elsevier-related matters
On-line access : Patience reminded the board members of a report he
wrote earlier this year which included his discussions with Friso
Veenstra. The latter proposed free access for all EAOG members for 2002,
starting November 1st, 2001 with 1 year of archives. The board members
requested an increase in the length of this duration and Veenstra
promised to ask his management if it were possible to increase it to two
years. van Graas mentioned that AAPG offers either hard copy or on-line
access with a back-up CD. In other respects, several members have
already access to full papers through Science Direct. However, we don't
know how many members have this access. It has been decided to ask
members who want to benefit from the Elsevier offer to send their e-mail
address to the new website officer or to fill out the corresponding page
on the EAOG website. An announcement will be made during the meeting
just before the Pieter Schenck ceremony.
Application for membership and provision of membership list : The new
website officer will be asked as a first task to modify the application
form and to provide Elsevier with a list of e-mail addresses. The
application form refers to the EAOG articles which were published in
vol. 20 and it was suggested to publish them again either in a
forthcoming journal issue and/or on the website. However, it was
mentioned that the articles have been amended at the Maastricht meeting.
The board secretary will thus check in the minutes what has been amended
and this point will be discussed at the next board meeting.
Elsevier was asked to give membership lists in Excel files to the
membership officer. Rowland noted that the current membership is similar
to last years (564 at the end of 2000 and 561 presently), but it may
increase later this year and will increase next year as a result of the
new members from the Nancy meeting.
Distribution of the journal : Veenstra was informed of several problems
in OG distribution. However, they appear to be rather scarce (Curiale
only received about ten complaints this year) and it was suggested to
create a space in the website for receiving these complaints.
Archie Douglas' successor : Douglas has decided to stop his job of
co-editor-in-chief in mid-2002. James Maxwell has agreed to take over
from Douglas. The board members thanked Douglas for the work he has
done.
Electronic submission : The board members agreed that electronic
submission and reviewing should start and recommended discussions
between the editors and Elsevier to study the processes involved. The
example of several other journals (EST, GCA) was cited. A proposal for
electronic submission and reviewing should be presented at the January
board meeting.
Item 5 : New board members
Despite the publication of a call for candidates in January (in the
journal, website and org-geochem mailbase) and further extension of the
deadline, no candidature applications were received by the Secretary.
The board members thus decided to nominate two candidates, Anthony Lewis
(Plymouth) and Francisco Gonzalez-Vila (Sevilla).
The term of Horsfield as chairman ends in 2002. After detailed
discussions via e-mail following on from the last board meeting in
January 2000, Patience was chosen as chairman-elect. He will thus take
over from Horsfield after the next board meeting in early 2002.
Since the work of the website officer and of the membership officer are
more and more closely related, it was decided to combine the two
positions. However, two new members have been nominated, hence no
additional member is needed to take the communication officer job. This
will result in the decrease of the board size by one.
The general assembly will be asked to approve the above changes in board
composition and the nomination of the new EAOG board members. Members
will also be informed of the new chairman.
Item 6 : Awards (Michaelis)
Three candidates were nominated for the Pieter Schenck Award after
having postponed the deadline. The committee, composed of Roger Summons,
Jacques Connan, Pierre Albrecht and Walter Michaelis, selected Kliti
Grice. It has been said that the criterion on the age limit of 35 years
will have to be clearly defined at the next board meeting.
Concerning the travel awards, Michaelis showed the number of
applications, acceptances and rejections in the last ten years. In 2000,
4 awards were given out of 9 applications. Only one application was
received prior to the first deadline (March 31st) which was granted.
However, Michaelis mentioned that the quality of the proposals was
sometimes low and the committee is complaining. The supervisors and/or
heads of host laboratories will therefore be asked to have a look on the
proposals before they are sent. The announcement in Organic Geochemistry
will have to be changed to indicate that there are 2 deadlines per year.
Item 7 : Journal report (Douglas)
Douglas reported that all issues for 2001 have been received to date
(Jan-Aug) and that the September issue is to be dispatched this week. He
also showed that publication proceeds smoothly with an average delay of
two months between acceptance and publication for 2000 and 2001. The
total number of papers received in 2000 was 159 of which 99 accepted, 37
rejected, 6 withdrawn and 17 in progress. For this year (Jan-Aug), 93
papers received, 28 accepted, 21 rejected, 1 withdrawn and 43 in
progress. 2 Special issues have been already published in vol 32 and 12
are expected for 2002/2003. The impact factor of Organic Geochemistry
rose from 1.29 to 1.39 in 2000 while those of GCA and EST are at ca.2.5
and 3 respectively. An index of authors, keywords, articles and special
issues is available at http://www.elsevier.com/locate/orggeochem.
Item 8 : Financial report (van Graas)
Van Graas showed the evolution with two year-steps of the incomes and
expenses. It shows a high variability of the incomes depending on
whether the IMOG made profits or not. As agreed on the previous board
meeting, the planned accounts for the coming few years show a gradual
reduction of our assets (not counting on income from the IMOG meetings).
On the long term (> 6-8 years) this will cause problems, so we should
keep this in mind when choosing the locations of the future meetings
(good options for sponsoring). It has been decided to consider a
possible increase of the membership fees after the next board meeting.
Before closing the meeting, the chairman thanked Rowland and Telnaes who
have been serving for 8 years on the board. As there was no other
business, the chairman closed the meeting at 9:45 p.m.
Paris, September 17th, 2001.
(Sylvie Derenne, secretary)
4. EAOG Website
The EAOG website came under new management in December 2000 and this
brief message is to introduce myself as the incumbent (I hesitate to use
the awful term, webmaster, although it's probably expected).
Having spent a while getting to grips with both the style of the site
and the way it works, I have now updated the content. I hope there are
no dead or out of date links but, please, if you find anything awry
contact me ([log in to unmask]) and I will leap into action and
attempt to rectify the situation.
I have some ideas on how to extend the site; however, I would like to
take this opportunity to ask if you, the target audience, have any
thoughts on possible improvements or additions. Whatever your
suggestions, large or small, please contact me.
Finally, and for those of you who may not know, the URL (in plain
language, that's the address) of the EAOG homepage is:
http://www.eaog.org/index.html ... bookmark it or add it to your
favourites now!
I look forward to a deluge of messages.
Your dutiful Webmaster,
C. Anthony Lewis
([log in to unmask])
5. Travel reports
A. Dr. Marie Russell, Oceanography Labs, University of Liverpool,
Liverpool L69 3BX, U.K. (Present address: Dept of Geography, The
University of Durham, South Road, Durham DH1 3LE, U.K.)
I received an EAOG Travel grant to visit the International Atomic Energy
Agency (IAEA) - Marine Environment Laboratory in Monaco to study and
apply compound specific isotope ratio mass spectrometry to selected
samples from the eastern continental shelf of the Faeroes-Shetland
Channel. Due to various unforeseen circumstances I did not travel to
Monaco until March 2000, but despite the delay I had a fruitful and
enjoyable visit to the IAEA Marine Laboratory and I thank both the EAOG
and the IAEA for the opportunity to pursue the proposed work. Special
thanks are due to Dr. Imma Tolosa of the IAEA for her help during, and
since, the study. Thanks are also due to the staff of the IAEA who made
my visit both successful and enjoyable.
Background
The proposal for this work arose from a study of the biogeochemistry of
the benthic boundary layer of the eastern continental slope of the
Faeroes-Shetland Channel. In this study an important enrichment of fresh
organic matter in surficial sediments was distinguished. This enrichment
appears to be related to the boundary between overlying North Atlantic
Water flowing in a north-easterly direction, and underlying cold water
that forms in the Norwegian Sea and flows to the south-west. The
enrichment of fresh material is decoupled from terrestrial material,
which is instead concentrated further down-slope. This demonstrates the
off-shelf transport of the latter and the different hydrodynamic
behaviour of rapidly settling fresh material and more degraded
terrestrial organic matter.
The de-convolution of transport pathways on the shelf/slope remains one
of the key goals of this (and other) research. It is of particular
importance in the environmental assessment of anthropogenic activity,
principally hydrocarbon exploitation, at the north-eastern margin of the
Atlantic Ocean. As part of the above work, an unusual series of high
molecular weight (C33 to C37) mid-chain ketones (Fig. 1) was identified
at one of the slope sites. This particular site has previously been
drilled, and appears to be contaminated (high PAH, Ba etc.). Similar
suites of ketones have previously been identified in archaeological
cooking pot shards and have been ascribed to a high temperature origin
from triglycerides (Evershed et al., 1995; Raven et al., 1997).
Proposal
The high concentrations of these compounds in the Faeroes-Shetland
Channel site, where there has been some drilling, lead us to speculate
that the compounds were not naturally-derived, but may result from
drilling activities, since common additives to drilling muds are often
derived from vegetable oils, one of the most common being rape seed oil.
There is a possibility that the ketones identified in the surficial
sediments at the contaminated site were formed during drilling, and may
therefore provide a valuable, specific marker for the dispersal of
drilling fines. On the other hand, the compounds may have an unknown
biological origin.
It would be expected that the lipid components of the vegetable oil
would have isotopic compositions distinct from those of the
autochthonous lipids produced in the water column. Therefore the work
proposed to be carried out at the IAEA Marine Environment Laboratory was
to shed some light on the origin of these mid-chain ketones by
determining their carbon stable isotopic compositions and comparing them
with those of the ubiquitous long chain alkenones (primary production
water column source) that are also present in the samples.
Results
The isotopic compositions of the alkenones and sterols (13dC = -24 to
-26 per mil) are consistent with an algal origin. However, the isotopic
composition of the mid-chain ketones (-18.9 per mil) is significantly
enriched compared to that of the alkenones and sterols, suggesting a
different source. Although the presence of these compounds may be
exceptional, their origin is of interest since they may turn out to be
potential markers for the dispersal of fines from drilling cuttings.
Alternatively they may have an as yet unknown biological source.
Additional work on samples of drilling mud additives is ongoing and may
provide further insight to this problem.
The results from this study will be presented at the 1st French Meeting
on Stable Isotopes, to be held in Nancy in December 2000.
References
Evershed R.P., Stott A.W., Dudd S.N., Charters S. and Leyden A., 1995,
Formation of long-chain ketones in ancient pottery vessels by pyrolysis
of acyl lipids. Tetrahedron Letters 36, No. 8, 8875-8878.
Raven A.M., van Bergen P.F., Stott A.W., Dudd S.N. and Evershed R.P.,
1997, Formation of long-chain ketones in archaeological pottery vessels
by pyrolysis of acyl lipids. Journal of Analytical and Applied Pyrolysis
40-41, 267-285.
Figure 1
2) During breaks in analysis (due to sample work up etc) an additional
short study was made of the isotopic composition of the isomers of the
C20 isoprenoid alkylthiophenes contained in solvent extracts from a
short stratigraphic section of the Lorca Basin, SE Spain. In addition
the isotopic composition of C25 highly branched isoprenoid
alkylthiophenes (HBIT) was also measured.
The structural isomers of C20 isoprenoid alkylthiophenes can be grouped
into two types - those with sulphur incorporated in a mid-chain position
and those with incorporation at the end of the chain. End-chain
alkylthiophenes are thought to be derived from the incorporation of
sulphur into phytol derived phytadienes, i.e. from the phytyl side chain
of chlorophyll a, and thus to represent an input from photosynthetic
organisms. A predominance of these isomers represents a normal marine
environment. The mid-chain alkylthiophenes are thought to derive from
sulphur incorporation into polyenes derived predominantly from geranyl
geraniol, the availability of which is restricted to anoxic environments
where Archaeabacteria and green and purple sulphur bacteria contribute
significantly to the biomass, e.g. in hypersaline environments.
The 13dC values for the end-chain isomers range between -18 to -19 per
mil for the normal marine sediments and between -22 and -25 per mil for
the hypersaline sediments. The mid-chain isomers have a 13dC value of
-19 to -22 per mil for the normal marine and -26 to -27 per mil for the
organic rich shales (hypersaline). The values for the carbonates are -15
and -23 per mil.
These values suggest that the mid-chain and end-chain isomers may indeed
have different biological precursors but the story does not appear to be
clear cut, particularly when the isotopic composition of other compounds
present in the extracts are taken into account.
The results from this study were presented at the 1st French Meeting on
Stable Isotopes, held in Nancy in December 2000.
B. Exchange Grant Report of Dr. Manuel Algarra González in Laboratoire
de Physico Toxicochimie des Milieux Naturels (LPTC), Université de
Bordeaux I.
"Solid Phase Enhanced Direct Spectrofluorimetric Determination of
Aromatic Compounds in Natural Waters"
Resume
Continuing the line of research fixed in Laboratoire de
Physico-Toxicochimie in University of Bordeaux I under the supervision
of Dr. Lamotte, was carried out the proposal of an analytical method to
determinate Polychlorinated Biphenyl Compounds (PCB´s) and Polycyclic
Aromatic Hydrocarbons (PAH's) in naturals waters using solid phase
extraction coupled with fluorescence spectroscopy.
A commercial extraction disk (ENVIÔ C18 purchased from Supelco) as solid
phase was used to investigate the optimal experimental procedure that
include kinetic of adsorption process, pH, ionic strength, and influence
of humic substances and presence of PAHs in the measurements. Detection
limits are determinate in <ng/L level. In addition, the feasibility of
applying the proposed method to determinate PCB's and PAH's in real
samples.
Scientific aspects carried out
Because of the widespread environmental occurrence of PCB's and their
well-documented toxicity among animal and human population, there is a
continuous interest in the development of reliable, practical, sensitive
and cheap methods for their analysis in natural media.
Previously a bibliography study to establish the lines of our purposes
were done and the most of papers found that the most of the methods
developed so far for the detection and determination of PCB's and PAH's
usually include an extraction step (liquid-liquid or adsorption on a
solid phase) followed by a chromatographic analysis. All these methods
require sophisticated instruments and several steps, which are known to
introduce substantial loss of the analytes and errors in the analytical
results, other kind of analytes can suffer chemical transformation,
moreover, both extraction methods, require the use of organic solvent
whose utilization is more and more subject to law limitation.
During the last 10 years however there have been some attempts to
perform direct spectroscopic detection directly on an appropriate solid
phase after adsorption. The interest in such a technique lies on the
fact that it is a solvent-less method and it allows to avoid both
elution of the solid phase and chromatographic steps by performing a
direct spectroscopic analysis of analytes mentioned before. In the
present work we have evaluated a solid phase extraction method of PCB's
and PAH's in water, based on extraction with a fiberglass C18 inverse
phase coupled with a fluorescence detection and quantification directly
on the phase. It was observed that only solid phase microextraction
(SPME) is using actually as analytical method where is not necessary to
use solvents to extract analytes from the waters' samples. In the case
of solid phase extraction, recent works have shown that it is possible
to avoid elution of the solid phase and chromatographic steps by
performing a direct spectroscopic analysis of PCB's and PAH's pollutants
from the aqueous medium directly on an appropriate solid phase after
extraction.
Our first task was to set the experimental procedure in order to
optimise the reproducibility and sensitivity of the method. This work
included:
(i) the design of a sample holder adapted to the sample compartment
of the fluorometer.
(ii) the design of a special device for adsorption which comprised a
200 ml vial with a cover where are set both a motor for stirring and the
sample holder.
Wall adsorption problems were avoided by using only stainless steel for
all the material in contact with the water samples.
Kinetic adsorption and calibration curves were determined for eleven
PCB's (IUPAC nº 3, 15, 37, 52, 77, 101, 118, 126, 138, 153 and 169)
which were determined to be readily adsorbed on the C18 phase from pure
water and from water in the presence of humic substances (10 mg L-1).
Detection limits (LOD) were determinate in the range 0.2-2 ng ml-1 for
the investigated PCB, that is a value close to the concentration found
in river waters in contact with highly contaminated sediments. Linear
dynamic ranges (LDR) were determined with respect to immersion time in
order to optimise the method in the condition where equilibrium between
the liquid solution and the solid phase is far to be reached. They were
estimated to be in the range 0.2-25 ng mL-1 (ppb) for most analytes.
Convenient immersion times were found to be around 30 min. The effect of
various physical parameters and interferences were also investigated
leading to the following conclusions:
(i) In pure water, pH and ionic strength were found to have no effect.
(ii) At concentration normally found in polluted water, PAH's were found
not to interfere with PCBs. The only problem is with low molecular PAHs
whose fluorescence spectra may overlap PCBs spectra.
(iii) Humic substance were found to compete with the adsorbing phase by
sequestering partly the PCBs molecules. Stern-Volmer constants were
evaluated (mean value K » 1.1x103 mg-1 ml). In practice, compared to
pure water, in water containing about 10 mg l-1 of humic acids, a
reduction of about 60% of the intensity was observed. Preliminary
experiments have showed that this decrease can be reduced at high pH but
more measurement must be done to confirm this effect.
Instrumentation
Measurements were made with a commercial fluorometer (HITACHI F 4500).
To define the best sensitivity UV/VIS spectroscopy was employed to
detect the excitation wavelength of every analyte and blanks in the
same way when fluorescence measurements were done, blanks were checked.
Quantum yields of analytes were determined by Parker-Reeves method
(using biphenyl as reference in cyclohexane), Table 1. Linear dynamic
ranges were determined with respect to immersion time in order to
optimise the method. Although far from equilibrium, convenient immersion
times are found to be around 30 min.
Table 1. Photophysical and analytical figures of merit of the
investigated PCBs and PAH's
PCB's congeners Ffa x 10-2 Log Kow Calib. slope LOD (ppb)
PCB3 (4-chloro.) 2.4 ± 0.2 4.7 872.7 0.07
PCB15 (4,4'-dichloro.) 2.5 ± 0.2 5.1 144.8 0.40
PCB37 (3,4,4'-trichloro.) 0.95 ± 0.05 5.5 224.2 0.30
PCB52 (2,2',5,5'-tetrachloro.) 0.40 ± 0.08* 5.9 nd nd
PCB77 (3,3'4,4'-tetrachloro) 4.5 ± 0.2 5.9 140 0.50
PCB101 (2,2',4,5,5'-pentachloro) « 0.1 6.3 nd nd
PCB118 (2,3',4,4'-5-pentachloro.) 0.35 ± 0.05 6.3 58
1.0
PCB126 (3,3',4,4'5-pentachloro) 0.81± 0.05 6.3 73.6 0.8
PCB138 (2,2',3,4,4',5'-hexachloro.) « 0.1 6.7 nd nd
PCB153 (2,2',4,4',5,5'-hexachloro.) 0.30±0.05* 6.7 nd
nd
PCB169 (3,3',4,4',5,5'-hexachloro.) 0.97±0.05 6.7 301.5
0.20
* : Possibility for the presence of impurity
Conclusions
In the present work we have shown that our method can be used for a
global determination of PCB's and for identification of PAH's. So the
method appears suitable to determine the presence of this class of
pollutants in natural waters and may serve as an alert method to detect
these compounds in groundwater contaminated by soil or sediments. Its
main advantage is its simplicity.
In the case of PCB's, owing to the low concentration usually found in
most environmental waters, usually well below the ng mL-1 range (Table
1), its sensitivity needs to be substantially improved before being
applied to moderately polluted ground water. Such a goal could be
attained by trying different types of phases and developing more
efficient and sensitive methods for fluorometric detection. Two other
possibilities for improving the sensitivity of the method would be first
to eliminate the interference with humic substances and second to
dechlorinate the PCBs molecule in order to detect only biphenyl whose
fluorescence quantum yield is much higher. Others experiments are in
progress with more polar analytes like as chlorophenols derivatives,
persistent pollutants like as PCB's in environmental media and
carcinogenic effects in humans, experiments with this kind of analytes
in C18 were carried out, but no good results were obtained, for that
the present work will continue in University of Málaga to improve the
analytical method and extend its applicability
In the case of PAH's, the LOD has been determined to be lower than 0.1
ppb for the most fluorescent compounds. This result shows that the
method can be applied to detect PAH's pollution in a variety of
contaminated natural waters. As an example, some measurement has been
performed on sea water samples contaminated by oil spill. In that case a
clear fluorescence signal indicating the presence of PAHs due to oil
contamination have been observed
Málaga 4th July 2001 Manuel Algarra González
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