Number 59 April 1995
MAFF UK - DIOXINS IN PVC FOOD PACKAGING
Index to MAFF UK Food Surveillance Information
Sheets, 1995
See also:
1: MAFF UK - Metallic Compounds
in Plastics (July 1993)
15: MAFF, UK - Hydrocarbons in
Chocolate (October 1993)
25: MAFF,UK - Compositions of Films
used to Wrap Food (February 1994)
26: MAFF, UK - Formaldehyde in Tea
Bag Tissue (May 1994)
35: MAFF, UK - Survey of Benzene in
Food Contact Plastics (September 1994)
38: MAFF, UK - Survey of Styrene in
Food (October 1994)
47: MAFF, UK - Fluorescent Whitening Agents
(January 1995)
60: MAFF, UK - Phthalates in Paper and
Board Packaging (May 1995)
66: MAFF, UK - Grease Proofing Agents in
Paper and Board (June 1995)
72: MAFF, UK - Curing Agents in Carton Board
Food Packaging (July 1995)
90: MAFF, UK - Survey of Paper and
Board Food Contact Materials for Residual Amine Monomers from Wet
Strength Agents (May 1996)
189: MAFF UK - Total Diet Study:
Styrene (November 1999)
Summary
MAFF's Food Safety Directorate has completed a survey of eight samples
of poly (vinyl chloride) (PVC) food packaging for dioxins. This survey was
carried out to investigate reports that work in Sweden showed high levels
of dioxins might occur in PVC food packaging. The aims of the survey were
to investigate whether the Swedish reports apply to food contact materials
on sale in the UK and assess the levels of dioxins that might migrate from
PVC food packaging into food. The 'upper bound' concentrations of dioxins
found in the samples ranged from 2.6-6.9 nanograms of toxic equivalent (ng
TEQ)/kg packaging. In many cases the concentrations of dioxins were only
slightly higher than the limit of detection. Very low levels of dioxins
were found in all the PVC samples examined but these levels are unlikely
to make a significant contribution to the overall levels in food. The
levels found are unlikely to pose a risk to health and no further
surveillance of PVC food packaging for dioxins is planned.
Background
The term 'dioxins' refers to a group of closely related compounds which
includes polychlorinated dibenzo-p-dioxins (PCDDs) and
polychlorinated dibenzofurans (PCDFs). Dioxins are ubiquitous
environmental contaminants produced during the combustion of organic
materials (for example coal, petrol and wood) and during the incineration
of industrial and municipal waste. They are also formed as the unwanted
by-products of some chemical manufacturing and bleaching processes. Due to
their physical properties, dioxins tend to accumulate in fatty foods. Many
of the dioxins show little biological activity, but some have been shown
to be extremely toxic to some laboratory animals.
The dioxin 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is
considered to be the most toxic substance in the group. Dioxins are
present in the environment as a complex mixture of related compounds or
congeners and a system has been devised which expresses the toxicity of
all the congeners relative to the toxicity of 2,3,7,8-TCDD. The
concentration of each dioxin is therefore 'weighted' and the total dioxin
concentration expressed in terms of a toxic equivalent (TEQ).
MAFF have an extensive surveillance programme which monitors the levels
of dioxins in foods and allows the dietary intakes of these substances to
be estimated. The results of this surveillance have been reported in Food
Surveillance Paper No. 31 'Dioxins in Food' published in 1992 and as
articles on dioxins in food in Food Safety Information Bulletin Nos. 33
(January 1993), 37 (May 1993), 43 (November 1993) and 54 (October 1994).
A survey has been carried out to investigate claims, based on work
carried out in Sweden, that high levels of dioxins are present in PVC food
packaging. The aims of the survey were to investigate whether the Swedish
reports apply to food contact materials on sale in the UK and assess the
levels of dioxins that might migrate from PVC food packaging into food.
Further, more extensive, surveillance would be carried out if the levels
gave cause for concern. Eight samples were selected to represent the types
and uses of PVC food packaging. This initial survey would indicate whether
a more extensive survey is required.
Results
The samples were analysed for the 17 different dioxins. The
concentrations of dioxins found, expressed as TEQs, are given in
Table 1. The concentrations range from 2.6 ng
TEQ/kg PVC in siphon tubing used for home brewing to 6.9 ng TEQ/kg PVC in
a sample of PVC cling film. The concentration of dioxins in a blank
(analytical procedure carried out without a PVC sample) was found to be
2.3 ng TEQ/kg. The values given are the 'upper bound' estimates of the
concentrations of dioxins, that is, when a congener could not be detected
in the sample, the limit of detection was used when calculating the total
TEQ for the sample. The 'upper bound' concentrations are therefore a
deliberate overestimation of the true concentration.
Table 1: Concentrations of dioxins found in
PVC food packaging |
Sample description |
Dioxin concentration (ng TEQ/kg) |
|
Cling film |
6.2 |
|
Cling film |
6.3 |
|
Cling film |
6.9 |
|
Cling film |
5.4 |
|
Siphon tubing (for home brewing) |
2.6* |
|
Bottle (orange drink) |
3.5 |
|
Bottle (vegetable oil) |
6.4 |
|
Bottle |
4.2 |
Note:
* The concentrations of 5 dioxin congeners could not be
measured in this sample. The internal standards could not be detected
due to masking by other chemicals in the sample. |
Interpretation
The 'upper bound' concentration of dioxins found in the samples was low,
ranging from 2.6 to 6.9 ng TEQ/kg PVC. To estimate the concentrations of
dioxins that might be present in the food as a result of dioxins migrating
from the PVC packaging it is normal to assume that 10g of PVC (whether
cling film or bottle) is used to package 1 kg of food. The maximum
concentration of dioxins in the food, due to migration from PVC packaging,
is therefore estimated to be about 0.07 ng TEQ/kg. This estimate assumes
that all of the dioxins present in the packaging migrate into the
food - in practice it is likely that only a small proportion would
migrate. The estimated concentrations are therefore a considerable overestimate
of the levels that are likely to arise in PVC food packaging in practice.
The Tolerable Daily Intake (TDI) for 2,3,7,8-TCDD is 0.01 ng/kg body
weight/day (equivalent to 0.6 ng TEQ/day for a 60 kg individual), as
recommended by an expert group convened by the World Health Organisation
Regional Office for Europe in 1990, and endorsed by the UK Committee on
Toxicity of Chemicals in Food, Consumer Products and the Environment
(COT). When estimating intake of chemicals from food packaging it is usual
to make the conservative assumption that an individual consumes 1kg of
food per day which has been packaged in the particular material. The maximum
possible intake of dioxins due to PVC food packaging is therefore
estimated as 0.07 ng TEQ/day. These levels are unlikely to make a
significant contribution to the overall levels in food and are unlikely
pose a risk to health. No further surveillance of PVC food packaging for
dioxins is planned.
Contact point
Dr D Watson
Additives and Novel Foods Division
Ministry of Agriculture, Fisheries and Food
Room 212 Ergon House, c/o Nobel House
17 Smith Square
LONDON
SW1P 3JR
Tel: (+44) (0)20 7238 6250
Fax: (+44) (0)20 7238 5331
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