Di-isopropylnapthalene(s) in food packaging
made from recycled paper and board : conclusion on mouse lymphoma
assay (MLA)
COM statement COM/00/S3 - February 2000 |
Introduction
1. The solvent Di-isopropylnaphthalene(s) (DIPN) has been identified in
samples of food packaging materials made from recycled board and in some
samples of food. (1) DIPN is manufactured by Rÿtgers Kureha Solvents
GmbH (RKS) and supplied to the printing industry. Recycled paper used in
paper and board manufacture may include carbonless and thermal copy papers
from office waste, in which DIPN is used as the solvent for the ink system.
The DIPN may not be completely removed by the treatment of the recycled
fibres and may be present in the finished board and thus migrate into food.
The COT has been considering the results of these surveillance investigations
and concluded that the toxicological information on DIPN was inadequate.
The COT recommended that further toxicological studies were required including
further mutagenicity and long-term studies with DIPN.
2. The previously conducted in-vitro mutagenicity data included two negative
bacterial mutation assays in a number of strains Salmonella typhimurium
and in Escherichia coli (WP2 UVrA) and a inadequate metaphase analysis in
CHO cells. A negative in-vivo micronucleus assay in mice using the
intraperitoneal route had also been reported.
3. Rÿtgers Kureha Solvents GmbH (RKS) submitted a mouse lymphoma assay
(MLA) which was considered by the Committee at is 20 May 1999 meeting.(2)
The Committee drew the following conclusion with regard to the new mouse
lymphoma assay:
i) The study had been inadequately conducted and reported. An equivocal
response had been documented in a number of trials both in the presence
and absence of exogenous metabolic activation (rat liver S-9 mix from
Aroclor 1254 pre-treated animals). The Committee agreed that no conclusions
could be drawn from this study.
ii) The Committee agreed that a repeat Mouse Lymphoma Assay should
be undertaken. The Committee agreed that further testing, and in particular
in-vivo studies may be required if positive results were obtained
in the repeat Mouse Lymphoma Assay.
4. A further mouse lymphoma assay was submitted to the 3 February 2000
meeting of the COM. (3) The Committee drew the following conclusion with
regard to the further mouse lymphoma assay.
i) The study had been adequately conducted and reported. A dose related
increase in mutant frequency was documented in the first trial (3 hour
exposure) conducted in the absence of exogenous metabolic activation
and evidence for a dose-related mutagenic effect was also documented
in one trial conducted in the presence of metabolic activation (rat
liver S-9 mix from Aroclor 1254 pre-treated animals). Negative results
were reported in further trials in the presence and absence of exogenous
metabolic activation (24 hour exposure).
ii) The Committee agreed that the results of the two mouse lymphoma
assays were similar. The evidence suggested equivocal mutagenicity in
the mouse lymphoma assay. The Committee noted however, that Di-isopropylnaphthalene(s)
contained no chemical groups which would be structurally alerting for
potential mutagenicity. In addition there was no evidence for a mutagenic
effect in other in-vitro mutagenicity tests or in an adequately performed
in-vivo micronucleus assay in mice. The Committee agreed that no further
mutagenicity testing was required.
References
1. MAFF (1999). Diisopropylnaphthalenes in food packaging made from
recycled paper and board. Food surveillance information sheet number
169, January 1999.
2. Huntingdon Life Sciences (1999). DIPN Mammalian cell mutation assay.
Report RTG 001/984972, dated 3 February 1999.
3. Huntingdon Life Sciences (1999). DIPN Mammalian cell mutation assay.
Report RTG 002/994287, dated 12 November 1999.
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