IJUP08 - Universidade do Porto

An expeditious method for determination of residues of
organochlorine pesticides in sediments and its application to
Portuguese estuarine areas
P. N. R. Rodrigues 1,2,* , P. N. Carvalho 1,2 , F. Alves 1,2 , R. Evangelista 1,2 , M. C. P.Basto 1,2
and M. T. S. D.Vasconcelos 1,2
1 Department of Chemistry, Faculty of Sciences, University of Porto, Portugal.
2 CIMAR/CIIMAR – Centre of Marine and Environmental Research, University of Porto, Portugal.
* pedronrrodrigues@gmail.com
Organochlorine pesticides (OCPs) integrate the semi volatile persistent organic compounds
(POPs) that exhibit potentially harmful effects to the environment [1]. As most of the
POPs, OCPs are lipophilic, persist in various media and some can be transported over long
distances to regions where they have never been used [2]. As OCPs can be introduced into
the aquatic environment and accumulated in sediments by several pathways, levels of
OCPs in sediments should be determined and controlled whenever possible.
Analysis of OCPs implicates extraction of these compounds from the sediment, which is
difficult owing to strong interaction among OCPs and different constituents of the
sediments, particularly organic content.
A method involving a combination of microwave assisted extraction, headspace solidphase
microextraction (HS-SPME) and gas chromatography coupled to mass spectrometry
(for identification and quantification) or gas chromatography with electron capture
detection (for quantification of previously identified OCPs) with complete automation of
the HS-SPME procedure, which increases the sample throughput, was optimized. To
minimize matrix effects, a step for elimination of sulphur interference was included when
required and standard addition was used for calibration purpose. Method validation was
performed by means of analysis of ten OCPs in reference sediments with certified values:
(a) Metranal TM 16, from Analytika Ltd. (Prague, Czech Republic); and (b) CNS300-04-100
from Resource Technology Corporation (Salisbury, United Kingdom).
The method resulted effective, relatively simple and fast, and it was applied for monitoring
residues of OCPs from estuarine sediments of different Portuguese rivers. In this
communication, the characteristics of the method will be presented as well as the nature
and levels of OCPs found in estuarine areas of Portuguese rivers.
References:
[1] Zhou, R., L. Zhu, and Q. Kong (2007), Persistent chlorinated pesticides in fish species from
Qiantang River in East China, Chemosphere, 68, pp. 838-847.
[2] Li, Y.F. and Macdonald, R.W. (2005), Sources and pathways of selected organochlorine
pesticides to the Arctic and the effect of pathway divergence on HCH trends in biota: a review
Science of The Total Environment, 342, pp. 87-106.
Acknowledges:
This work was partially funded by Portuguese Foundation for Science and Technology (fellowship
awarded to Rafael Evangelista (SFRH/BD/20163/2004), the CONC-REEQ/304/2001 re- equipment
project and POCTI/CTA/48386/2002 project).
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