Appendix D - Dossier (PDF) - Tera

date: 20–JUL–2005
4. Ecotoxicity Substance ID: 71–43–2
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inactivated chloroplasts were run.
3. The phosphate buffer was 0.1 M at pH 6.8.
Test substance: Radiolabeled benzene (3 g; 225.7 MBq/g) was diluted with
unlabeled benzene to 30 g. After purification, the specific
activity of labeled benzene was 1.76 MBq/mmol (= 22.5
MBq/g).
Reliability: (2) valid with restrictions
Flag: Risk Assessment
18–MAR–2004 (1177)
Type: plant
Method: Test system and exposure regime
Cucumber and blackberry plants were maintained in a controlled
environment (20 degrees C, 16 hr daylength etc) and exposed to
either control air (passed though a charcoalfilter to remove
benzene) or ca. 1 mg/m3 benzene for up to 3months. Pot grown,
outdoor dwarf apple trees were exposed on two 7day occasions
to filtered air or 1 or 9 mg/m3 benzene within a controlled
environment cabinet.
Sampling and analysis
Three replicate samples of leaf disc, meristem or fruit tissue
were taken from individual plants and placed inside a
crimp–top headspace sampler. Samples were disintegrated
mechanically and analysed by headspace GC/MS. Background
(control) benzene concentrations were subtracted from all
vegetation samples (mean = 1 ng/g tissue). Samples of chamber
air were adsorbed onto ORBO–32 charcoaltubes, desorbed using
dichloromethane and analysed by GC.
Statistics
Applied, but methods not described.
Remark: Although under the controlled conditions of the study the
concentration of benzene in plant tissues was found to
generally increase following exposure to exogenous (air)
sources, the authors conclude that ingestion of contaminated
vegetation is not of significance unless high ambient levels
are maintained for a long duration.
Result: (Results are presented graphically. Values presented below
were obtained by interpolation.)
Appendix D: Benzene SIDS Dossier
Blackberry leaf showed significant benzene accumulation (up to
1000 ng/g), whereas the level in fruit remained relatively
stable (approx 10 ng/g). (Note: there was a single,
unexplained peak value in fruit 55 days into the exposure
period.)
There was little evidence of benzene uptake by cucumberleaves
(barely detectable), whereas variable amounts were found in
fruit (approx 2–25 ng/g) and meristem (up to approx5 ng/g).
Apple tree leaves showed variable uptake, with barely
detectable amounts after the first exposure and approx 40 ng/g
in old leaves, and approx 10 ng/g in new leaves, following the
second (higher) exposure. The concentration in apple flowers
after the first exposure was approx. 10 ng/g, while fruit
contained approx. 35 ng/g after the second exposure.
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