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.