English Abstract This report contains general information on phthalic
anhydride concerning the existing standards, emissions, exposure levels and
effect levels. Since phthalic anhydride will rapidly hydrolyse to
o-phthalic acid in the presence of water, this reaction product is included
in the evaluation. In general data on phthalic anhydride are very scarce
and incomplete, hampering a sound risk evaluation. In the Netherlands the
registered emissions (0.57 tonne per year) are small (0.0005%) compared
with the amount of phthalic anhydride produced, imported and applied
(approx. 110,000 tonnes per year). For the general population, inhalation
is considered the most likely exposure route. In one limited 8-month study
with guinea pigs a LO(A)EL of 8,500 mug.m-3 was derived for phthalic
anhydride. Based on the registrated emissions the exposure levels will not
likely exceed the 1 mug.m-3 level. From this one may conclude that the
risk of inhalatory outdoor exposure to phthalic anhydride to the general
population seems to be small, if present at all. As to oral exposure, an
tentative toxicological limit value of 0.375 mg.kg-1 bw per day NO(A)EL
was derived from a two-year carcinogenicity study, applying a large safety
factor (1,000). This tentative toxicological limit value is not likely to
be exceeded. No data are available on the toxicity of phthalic anhydride
and its main conversion product, o-phthalic acid, to aquatic and terrestrial
species. Data on the occurrence in the environment in the Netherlands are
scanty. Phthalic anhydride has been reported to hydrolyze very rapidly
(estimated half-life of approx. 1.5 minutes). Consequently, its product
is biodegraded rapidly as well. Taking into account the emission figures
the risk for aquatic and terrestrial life is expected to be small. It is
concluded that phthalic anhydride does not seem to present a significant
risk to humans or ecosystems in the Netherlands. Therefore it is
recommended not to stimulate in depth studies on phthalic anhydride but to
remove phthalic anhydride from the attention substances
list.