3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Food Chemistry & Biotechnology
P54 DIETARy ExPOSuRE MONITORING OF
PERSISTENT ORGANIC POLLuTANTS FOR
ThE CZECh POPuLATION
SYLVA SALáKOVá, JAnA KOLářOVá, IREnA
řEHůřKOVá and JIří RUPRICH
National Institute of Public Health – Centre for Hygiene of
Food Chains, Palackého 3a, 612 42 Brno, Czech Republic,
salakova@chpr.szu.cz
Introduction
Persistent organic pollutants (POPs) are organic compounds
that are resistant to environmental degradation through
chemical, biological and photolytic processes. They
are highly persistent, lipophilic and bioaccumulative industrial
contaminants. POPs accumulate in fat of organisms.
Some of them are classified as possible human carcinogens.
Therefore POPs have been controlled as contaminants in the
Czech environment for many years.
The Centre for the Hygiene of Food Chains in Brno
guarantees “the Project on Dietary Exposure to Selected
Chemical Substances” whose objective is to describe dietary
exposure to selected chemical substances for the Czech population.
In the framework of this project 26 OCPs – p,p´-DDD,
o,p´-DDD, p,p´-DDT, o,p´-DDT, p,p´-DDE , o,p´-DDE,
endosulfan I + II, endosulfan sulfate, HCH(alpha-, beta-,
gamma-, delta-,), aldrin, endrin and its metabolite endrinketone,
dieldrin, methoxychlor, heptachlor and its metabolites
heptachlorepoxide (A + B), HCB, alpha and gamma chlordane,
mirex and the seven most significant indicators of
PCBs (28, 52, 101, 118, 153, 180) have been monitored since
1994. Cis- and trans- chlordane, oxychlordane and mirex
were quantified since 2002.
Experimental
PCBs and OCPs were determined in samples which
represent more than 95 % of composition (by weight) of
current diet for the Czech population. First of all the samples
bought on the Czech market were subjected to culinary
treatment so that they could be analyzed under the same
conditions as they are consumed. The result of the preanalytical
treatment was a homogenous sample, which was then
analyzed. The analytical procedure consisted of: (i) isolation
(extraction) of the analytes from the matrix, (ii) removal of
co-extracted compounds of the matrix and (iii) analysis using
the GC method. The procedure was optimized as a multiresidual
analysis for determination of polychlorinated biphenyls
(PCBs) and organo-chlorine pesticides (OCPs).
S t a n d a r d s
We used a single standard solution of PCBs and OCPs
(concentration 10 ng µl –1 , Dr. Ehrenstorfer) for preparation of
calibration standard. Internal standards (PBB1, PCB 209 and
2,4,5,6-Tetrachloro-m-xylene, concentration 10 ng µl –1 , Dr.
Ehrenstorfer) were used to determine the extent of recovery
of the analytical procedure.
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S a m p l e P r e p a r a t i o n
The amount of the food samples for the analysis was
50–200 g. Samples were ground with anhydrous sodium
sulphate and spiked with PBB1, PCB 209 and 2,4,5,6-Tetrachloro-m-xylene
as recovery standards. The first step of the
preparation is the extraction. The type of extraction depends
on the matrix of sample. The fat samples were extracted on
automatic extraction device (Buchi Extraction System B-811)
by hot solvents, non-fat samples were extracted at high speeds
homogenizator (Polytron PT 3100) and the liquid samples
were extracted in the liquid/liquid system. The mixture of
petroleum ether/acetone (ratio 2 : 1) or dichloromethane was
used as a solvent for liquid samples. The extracts were evaporated
to constant weight in a rotary evaporator and the
lipids were determined gravimetrically. The sample extracts
were purified by a gel permeation chromatography (GPC) on
column “Envirogel GPC cleanup column” fy Waters and by
column chromatography on Florisil.
G C A n a l y s i s
The cleaned samples were analyzed by gas chromatograph
(GC-Hewlett-Packard 5890) with two column system
using different stationary phases and ECD detectors. For analyses
were used following conditions:
column: DB 5 (30 m × 0.25 mm × 0.25 µm)
column: DB 17(30m × 0.25 mm × 0.25 µm)
initial temperature: 90 °C
initial time: 2 min
temperature rate 1: 15 °C min –1
final temperature: 180 °C
temperature rate 2: 3 °C min –1
final temperature: 220 °C
temperature rate 3: 1 °C min –1
final temperature: 250 °C, final time 0.67 min
run time: 52 min
The method for the determination of POPs is accredited
by the Czech Accreditation Institute by the CSn En ISO/IEC
17025 Standard. Quality control of the results was conducted
by the means of testing materials (TM) and certified reference
materials (CRM). Certified reference material for PCBs was
BCR 350 (mackerel oil) and certified reference material for
OCPs was BCR 598 (cod liver oil) and BCR 430 (pork fat).
Limits of quantification, depending on the type of the matrix,
ranged between 0.002 and 0.05 µg kg –1 .
Results
Every year from 1994 to 2007 the content of 37 POPs
was determined in the samples of foodstuffs. 110 samples
of foodstuffs are analyzed per year. The highest content of
POPs was observed in fishes, meat products, butter and milk
products.
The results showed that the most abundant of all the
measured analytes were p,p´-DDE and PCB 138, 153,180.
The highest concentrations of these analytes were repeatedly