Phthalates in school supplies
2. How was the Danish study on phthalates in school supplies conducted?
- 2.1 What was the methodology followed?
- 2.2 What are the weaknesses of the Danish study?
2.1 What was the methodology followed?
A number of items, including erasers, were analysed for
Source: Allen Pope
The Danish Environmental Protection Agency (Danish EPA) tested
school supplies for the presence of
phthalates as part of a
wider programme that investigates exposure and possible risk of
chemicals in consumer products and articles. After a market
survey, a number of school bags, toy bags, pencil cases and
erasers were bought and analysed.
A chemical analysis was carried out to detect the presence of
various substances in these articles. More specifically:
- chlorine content
was investigated in order to identify the products
- some product samples were tested to see what types of
polymer they contained.
- X-Ray analysis
was used to assess the presence of chlorine,
bromine, tin, sulphur
- the potential release of volatile organic
(VOCs) was evaluated.
- some product samples were analysed for specific
metals, colouring agents,
- to what extent chemicals pass from the sample to
artificial sweat and saliva was studied.
Of all products, 46 including 26 erasers, were tested in more
detail to find out how much they contained of each chemical.
Nine of the erasers contained
phthalates. Three of them
contained 22-44% of DEHP
and six contained 32-70%
DINP. The study also found
DBP in some of the
products, but did not measure the total content of these
phthalates. It studied the extent to which chemicals from 14
products pass into artificial sweat and saliva, but none of
these products were erasers. The results showed that DIBP and
DEHP were released by 11 and 5 products respectively.
The major exposure route to
phthalates from the
products investigated in the Danish study is by licking, chewing
and swallowing small pieces of the item. The
SCHER agrees with the
conclusion that erasers may be the only relevant source for
phthalates from the selection of school supplies investigated,
and the other products tested do not present a health risk for
children. The only potential source of concern in the study was
exposure to DEHP from
erasers through sucking and chewing, and this is the main focus
of the present opinion.
2.2 What are the weaknesses of the Danish study?
In general, the way the Danish study was designed and the
report derived from this study contain several weaknesses, which
makes it difficult to come to conclusions based on the results.
The report from the Danish study is confusing as not all details
required for an evaluation are included. Furthermore, the
information it gives on quality assurance of the analyses is
limited and sometimes contradicting.
The SCHER agrees that
the presence of phthalates
in school supplies other than erasers is of low concern since
contact with the skin – which is limited – may be the only
reasonable way for children to be exposed and that only small
amounts of phthalate go through the skin. However, erasers that
contain phthalates may be of concern because they can leach
DINP when children put them
in their mouths. But it was not possible for the SCHER to make a
proper risk assessment of
this potential exposure because of deficiencies in the report.
How much DEHP pass into
artificial saliva was only studied from one eraser in a sample
that had been cut into small pieces. This gives a much larger
surface area of contact between the eraser and the artificial
saliva and results in excessive leaching of the plasticizer. It
was calculated that the results could be six times higher than
the true values. Proper analyses on the release of DEHP into
artificial sweat give much lower values and are further evidence
that the results of the Danish study are overestimates.
- When the artificial saliva was analysed to measure the
amount of DEHP that had
leached into it, it still contained small pieces of eraser that
had not been removed and this could overestimate DEHP release
- The uncertainty of the results is reported to be 50%, which
indicates that the chemical analyses are of poor quality.
- The Danish study should have used artificial gastric juice
to measure a potential release of phthalate from swallowed bits
In summary, the SCHER
considers that due to the many weaknesses in this study and its
reporting, the figures given for the amounts of
DINP leached cannot be used
as a basis to assess the potential health risk of
phthalates released from