Opinion on the results of the Risk Assessment of: Cumene (C9H12), CAS N° : 98-82-8, EINECS N° : 202-704-5 carried out in the framework of Council Regulation (EEC) 793/93 on the evaluation and control of the risks of existing substances - Opinion expressed at the 15th CSTEE plenary meeting, Brussels, 5th of May 2000.
Terms of reference
The CSTEE on the basis
of the examination of each Risk
Assessment Report is invited to
examine the following issues:
1. Does the CSTEE agree with
the conclusions of each Risk
Assessment Report?
2. If the CSTEE
disagrees with such
conclusions, the CSTEE is
invited to elaborate on the
reasons for this divergence of
opinion.
GENERAL COMMENTS
The CSTEE agrees with
the general conclusions of the
Report for both the environment
and the human health parts.
However, as cumene degrades
slowly in groundwater or
seawater and because the only
available bioaccumulation study
is of doubtful value, more
research into its biological
impacts and persistence in
these waters would be highly
valuable. PEC local could not
be derived for 6 of the 8
plants due to insufficient
data; this data is essential to
complete the risk assessment
for all plants.
With regard to the
quality of the document, the
human health part is
particularly poor. In addition
to numerous editing problems,
there are very many deficits in
the availability, description,
and interpretation of the
studies.
SPECIFIC COMMENTS
Environment.
Accumulation
An important piece of
information regarding
biodegradation is in a report
(Hüls) which is not available
for evaluation. A high
bioaccumulation potential is
expected due to the Pow of
cumene which is higher than 3.
Cumene degrades slowly in
groundwater and seawater but
the only available
bioaccumulation study is of
doubtful value to the RA.
Research into the biological
impacts and persistence of
cumene in these waters would
thus be desirable.
Aquatic compartment
(including sediments)
The assessment is based
on a large set of short-term
toxicity data on aquatic
organisms belonging to all
trophic levels of the aquatic
ecosystem (fish, invertebrates,
algae, bacteria).
Long term toxicity data
are available for freshwater
invertebrates and algae. A QSAR
estimation of the chronic
toxicity of cumene to fish is
also included.
A critical evaluation of
data is made in order to assess
reliability. Accordingly, the
PNEC water is based on a
suitable amount of information
and can be assumed as reliable,
both for freshwater and marine
ecosystem. A predicted (TGD)
PEC for local water is found,
in this report, to be three
orders of magnitude higher than
measured values. The
discrepancies are discussed
briefly and the used PEC is
given.
Data on sediment
dwelling organisms are not
available, but the equilibrium
partitioning method is applied
to calculate a PNEC sed. The
PEC regional for sediments is
calculated to 0.007 µg/kg,
which is said to be in
agreement with measured data.
However, the data given (page
28) are all higher, sometimes
much higher. This should be
discussed.
PEC/PNEC ratios are
always lower than 1 at local,
regional and continental
scales. However, it should be
noticed that it was only
possible to derive PEC local
for 2 of the 8 sites due to
insufficient data supplied by
industry. Thus there is a need
for further data to complete
the Risk Assessment for all
sites.
Terrestrial compartment
Because information are
restricted to toxicity tests on
plants, the PNEC for soil
dwelling organisms has been
calculated by EUSES program
using the equilibrium
partitioning method. This may
be acceptable considering the
Pow of Cumene.
PEC/PNEC ratios are
always lower than 1.
The conclusion of "no
need for further information
and/or testing" is generally
acceptable. However, it could
be advisable to carry out a
toxicity test on earthworms to
assess the local risk in the
case of pollution with
petroleum products.
Non compartment specific
effects relevant to the food
chain.
Both the likeliness of
indirect exposure and a high
bioaccumulation potential
derived from a Pow>3, make
the potential of cumene to
enter the food chain rather
high. However, because the
available data on the oral
toxicity of cumene on mammals
seem to indicate, so far, a
moderate toxicity, the
conclusion of "no need for
further information and or
testing ..." is deemed
acceptable.
Human Health
There is agreement with
the overall conclusion that
"there is at present no need
for further information and/or
testing or for risk reduction
measures beyond those which are
being applied already".
However, major weaknesses have
been found in this part of the
Risk Assessment Report.
The limited validity of
some studies is not mentioned
critically enough or a correct
conclusion from them is missing
(see for example chapter
4.1.2.2.3 and 4.1.2.2.5, second
part on p. 70).
The summary chapters for
the different toxicological end
points are too long and contain
too many details of minor
interest. Consequently, the
characteristic effects of the
substance are not shown clearly
enough (see for example chapter
4.1.2.2.5, p. 69-70, or
4.1.2.6.3, p. 76-77).
For chapter 4.1.2.2.2,
Study on mechanisms of
toxicity, p. 67-68, some
publications that have reported
important mechanistic data are
not quoted e.g.: Tanii et al.,
Neurotoxicol. Teratol. 16,
575-582, 1994, and Tanii et
al., Toxicol. Lett. 76, 27-31,
1995...;
The list of references
should be amended thoroughly
since:
- some studies are cited
twice (e.g. Bushy Run 1989, No.
52-621; Bushy Run 1989, No.
52-622, Smyth et al. 1951; Jany
1987 same as Yang 1987);
- several studies are
not attributable to the text
because of the same author and
year of publication (Bushy Run
1989; Dow 1985; Gulf Oil 1985;
Putman 1987);
- titles are missing in
several cases;
- publisher or other
important information is
missing;
- unpublished studies
are given without information
on type of experiment, study
laboratory, owner of the study,
etc., so they could not be
attributed to the description
in the text nor be ordered or
asked for by any reader of the
report.
- typing mistakes are
frequent.