CSTEE opinion on Chapters 6 and 8 (on risk issues) of the RPA ETD/99/502498 Final Report July 2000 - The Availability of Substitutes for Soft PVC Containing Phthalates in Certain Toys and Childcare Articles. Opinion expressed at the 22nd CSTEE plenary meeting, Brussels, 6/7 March 2001.
Terms of reference
The Committee on the
basis of examination of the
following report
- The Availability of
Substitutes for Soft PVC
Containing Phthalates in
Certain Toys and Childcare
Articles, RPA ETD/99/502498,
chapters 6 and 8 (on risk
issues),
is to answer the
following two questions:
1. Is the reported degree of
risk sufficiently justified by
the study
2. Is the study of a
good quality.
Introduction
The aim of the study was
to provide an overview of the
situation on the EU market
following restrictions on the
use of phthalates in certain
childcare articles and toys.
The study should address the
risks to the health of
children, including safety
aspects, of possible
substitutes. Information on
toxicological profile and
potential migration as well as
an appreciation of the
sufficiency of data were
requested. The CSTEE is invited
to comment on the risk
assessment chapters of the
report.
General comments
Response to question
1:
The reported degree of
risk from the use of the
plasticisers o-acetyltributyl
citrate (ATBC) and diethylhexyl
adipate (DEHA) in PVC childcare
articles and toys is not
sufficiently justified, since
it is not possible to perform
an adequate exposure assessment
on these substances.
Response to question 2:
The quality of the study
leaves much to be desired. The
toxicological information on
ATBC and DEHA is simply
duplicated from a previous
CSTEE opinion. The report
presents margins of safety and
guidance values for ATBC and
DEHA. This is not justified
given the lack of exposure
information. Also, the report
fails to refer to the safety
assessment on butylated
hydroxytoluene (BHT) performed
by the EC Scientific Committee
on Food.
Specific comments
Chapter 6
The heading for the
Chapter 6 incorrectly uses the
term "risk analysis", whereas
the correct one would be "risk
assessment".
The Chapter 6 purports
to perform a risk assessment of
two plasticisers which may be
used in PVC plastics,
o-acetyltributyl citrate (ATBC)
and diethylhexyl adipate
(DEHA), and one additive which
may be used in substitute
plastics, butylated
hydroxytoluene (BHT). The text
presented on ATBC and DEHA on
exposure and toxicological
effects is almost exclusively
an abridged duplication of the
CSTEE opinion (of 28 September
1999) on those substances. In
this respect, the present
report has no additional value.
The CSTEE has several
critical comments to the Table
6.1 Summary of Risk Analysis
for ATBC. The table refers to
the estimate of the CSTEE for
the intake dose for children
from toys. It should have been
pointed out that this was a
maximal figure given certain
assumptions, namely that ATBC
is extracted more or less as
effectively as the phthalates
from PVC and that the same
concentrations are used in the
polymers. The table also
presents a margin of safety
(MOS) value. The CSTEE
disagrees to this, since its
conclusion was that it is not
possible to estimate the
exposure levels to ATBC from
mouthing soft PVC toys and its
NOAEL, due to the data gaps.
Therefore, a guidance value for
maximum tolerable extractable
amount of ATBC in PVC toys
cannot be assigned, in contrast
to what the table presents.
Regarding the risk
assessment of DEHA presented in
Table 6.2, the CSTEE has the
same critical comments as to
the one on ATBC above. It is
not possible to estimate DEHA
intake doses for children from
PVC toys, maximum emission
rates from the toys and an
intake dose. Thus, the
presentations of a MOS value
and a guidance value are not
warranted by the existing data.
The report has presented some documentation on BHT as an example of an additive used in substitute plastics. Why BHT in particular has been singled out from the many additives that are used in substitute plastics, is not well substantiated. The intention of the study has been to highlight that there exists a potential risk associated with other organic additives used in such products. This would be the case for any substance that may be extracted from plastics during use, making this example of limited value. It is remarkable that the report does not refer to the safety assurance performed by the EC Scientific Committee for Food (SCF) on BHT (22nd Series, 1989). The SCF has identified a NOAEL of 5 mg/kg bw/day and established an ADI of 0-0.05 mg/kg bw based on thyroid, reproduction and haematological effects in the rat (the present report gives a NOAEL of 7.5 mg/kg bw/day and a TDI of 0.075 mg/kg bw/day). The SCF's view was that there was a threshold for BHT carcinogenesis related to liver enzyme induction, reinforced by an overall lack of evidence of genotoxic effect in in vivo systems. Since the NOAEL demonstrated for carcinogenesis was higher than that obtained for other toxicological effects, the ADI was determined from the latter.
The report recommends
that a thorough risk assessment
of the use of BHT as an
anti-oxidant in children's toys
is clearly needed. The CSTEE
does not agree to this,
although information on the
exposure to BHT from use of
substitute plastics would be
desirable. Since the
concentration of BHT in
substitute plastics is
approximately a hundred-fold
lower than the concentration of
phthalates in PVC plastics, and
the NOAELs of BHT, DEHP and
DINP are within the same order
of magnitude, it is unlikely
that BHT in substitute plastics
will represent a health risk.
Chapter 8
The report concludes
that the margin of safety for
DEHA would appear to be less
than for ATBC. This would only
be true if migration rates for
the two substances were known
and the preliminary effects
assessments would hold up as
more effects data become
available. The CSTEE does not
agree to the suggestion that
ATBC may be preferable to DINP
on health grounds but that DEHA
may not, since the exposure
assessments of ATBC and DEHA
are not possible to conduct due
to lack of data. Any discussion
of preferability from a risk
assessment standpoint would
have to be made on a comparison
of the respective margins of
safety, for this both the
exposure information and the
NOAEL values need to be
factored in.
The statement that BHT
should be considered more
hazardous than phthalates, ATBC
and DEHA is not quite correct,
since the NOAEL of DEHP is 3.7
mg/kg bw/day vs. the NOAEL for
BHT of 5 mg/kg bw/day. However,
the NOAEL for BHT is lower than
those for DINP (15 mg/kg
bw/day), ATBC (100 mg/kg
bw/day) and DEHA (30 mg/kg
bw/day). As pointed out, the
likely risk associated with the
use of BHT in substitute
plastics would be decreased
compared to the use of
plasticisers in PVC plastics.
This could have been made more
explicit by comparing the
concentration of BHT in
substitute plastics (0.2-0.5%)
vs. the concentration of
plasticisers in PVC plastics
(10-60%).