3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Food Chemistry & Biotechnology
P88 MONITORING OF MERCuRy CONTENT
IN ThE FOOD bASKET FOR ThE CZECh
POPuLATION DuRING 1994–2007
J. řEHáKOVá, I. řEHůřKOVá, J. RUPRICH, J
KALVODOVá and D. MATULOVá
National Institute of Public Health – Centre for the Hygiene
of Food Chains, Palackého 3a, Brno 612 42 Czech Republic,
rehakova@chpr.szu.cz
Introduction
Mercury belongs to group of heavy metals. In nature
mercury can be found in various forms (organic and inorganic
compounds, elementary Hg 0 ) with different toxicity. For
human organism all mercury forms can be toxic. The most
important and the most danger forms are alkyl-mercury compounds
like methylmercury (MeHg) and inorganic compound
like Hg 2+ . The hazard is connected also with cumulative properties
of mercury. The highest concentrations are measured
in kidneys, liver and spleen.
Less frequent acute intoxication causes vomit, diarrhea
and abdominal ache. More important is a risk of chronic intoxication.
Exposure can lead to cerebral paralysis, cephalonia,
deafness, blindness and high blood pressure (Minamata
disease) 1 . MeHg as the most danger mercury form comes through
blood-brain barrier and via placenta can be transported
into fetal brain.
Main exposure routes for mercury are inhalation and
digestion... Disputative question is long-term influence of
amalgam fillings. Mercury is very well absorbed after oral
exposure (95 % MeHg is absorbed). Due to potential health
risks it is necessary to monitor the mercury content in foodstuffs
of vegetable and as well as animal origin. Plants and
animal contamination can be caused by growing in contaminated
environment (industry wastes and exhalation). Important
source of mercury exposure especially in seaside countries
are fish.
Many studies have been published about the determination
of mercury in foods. Centre for the Hygiene of Food
Chains in Brno has been involved in the monitoring of the
content of total mercury in foods (see “The Project on Dietary
Exposure of the Czech Population to Selected Chemical Substances”
2,3 ). This project has been started in 1994 and the
third period runs in this time. The aim of this monitoring
programme is an assessment of dietary exposure, comparison
with toxicological reference points, and characterization of
health risks. To achieve these goals it is necessary to perform
a systematic monitoring of the mercury content in the food
basket of the Czech population as well as to know consumption
of individual foods.
This work summarizes the mercury content found in
individual foods in our laboratory during past 14 years. Also
their contribution to the total dietary exposure and validation
by using of biomarkers are included.
s777
Methodology
The analyzed foods were selected according to the
knowledge of their consumption by the average person in
the Czech population 4,5 . In total 143 kinds of foodstuffs were
selected and studied in specific time periods. Food samples
were collected in 4 regions (12 sampling towns) and delivered
to Centre of Hygiene of Food Chains in Brno. This
organization represents 572 food samples that have been processed
during two-year period. Some kind of foodstuffs (more
frequently consumed) are sampled repeatedly and measured
every year (e.g. milk or potatoes even 2 × per year and town),
others (less frequently consumed) are sampled and measured
only once in the whole two-years period. In total 880 individual
samples were measured in this period. After delivery of
samples into the Centre of Hygiene of Food Chains in Brno,
the samples undergo the culinary treatment in pre-analytical
laboratory so that they are analyzed in the same state as they
are consumed. The samples are then homogenized and delivered
into the central analytical laboratory for further treatment
and analyses.
In analytical laboratory mercury content (as a total
mercury) is determined by AAS method using principle of
selective system AMA 254 with solid sample dosing without
previous analytical preparation. Optimized method provides
adequate sensitivity for the determination of the mercury in
foods. The limit of quantification is 0.1 μg kg –1 for a minimal
sample weight 200 mg. The degree of recovery ranged from
95 to 105 %. The RSD of repeatability does not exceed 10 %.
This method is accredited according to ČSn En ISO/IEC
17025:2005. To ensure accuracy of the results matrix reference
materials as well as various internal test materials are
used. In addition our laboratory participates in proficiency
testing (FAPAS, IMEP etc.).
Results
The content of total mercury was monitored in 143 kinds
of food representing so called food basket of the Czech
population. Based on previous experience only fifteen kinds
of food with the highest measured mercury content were
selected and visualized in Fig. 1. This figure shows foods
with their corresponding concentration values. The dietary
exposure is influenced not only by the content of mercury in
the given food, but also by the quantity of consumed foods
To calculate the dietary exposure doses it is also necessary
to take into account the changes caused by the culinary treatment
of the given food which are described by the so called
culinary factor 3 . The influence of both the consumption and
culinary factor on the final exposure dose is demonstrated by
the following figure. The fifteen most significant exposure
sources of total mercury are given in Fig. 2. In both figures
(1.,2.) concentration data are used from the last monitoring
period 2006–2007.
Foodstuffs listed in Fig. 1. and Fig. 2. are traditionally
highlighted in first places during whole period of monitoring
program (1994–2007). Fig. 3. shows the changes in measured
content of total mercury [μg kg –1 ] in five selected most