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EC number: 292-607-4
CAS number: 90640-86-1
Distillate from the fractional distillation of coal tar of bituminous coal, with boiling range of 240°C to 400°C (464°F to 752°F). Composed primarily of tri- and polynuclear hydrocarbons and heterocyclic compounds.
of GC analysis in blood (non-labeled
The concentration of the 12 selected
chemicals was found to be below the limit of detection (individual LODs
see "Any other information.... above) in all serial plasma samples from
all collection time points during and following an 8h exposure to a
single finite application of the creosote test substance. These results
suggest that all
12 target chemicals disappeared very quickly, were metabolised upon
first pass through the skin and likely have negligible bioavailability
(Report p. 28). See also distribution of radioactivity (below).
of LSC analysis in organs and body fluids (Report Tab. 4 / Attachment):
After 8 h
(exposure phase), 3.14 % of the applied dose was found in the carcass
and >0.2 % in liver and even lower in other organs, while
only marginal label was detectable in blood (> 0.05 %).
In the post-exposure period over 21 days), radioactivity in the carcass
and organs decreased to below quantification limits, while increasing in
the urine and feces. This provides evidence that creosote components do
not tend to bioaccumulate but are excreted rapidly (see Attachment).
(Report, Tab. 4 / Attachment)
After 8 h
(exposure time): absorbed 6.34 % [SD±0.81%]
of the applied dose, tape-stripped skin 1.55 ±0.30%,
and tape strips of the stratum corneum
(SC) 6.89 ±2.74%. SC turnover may reduce absorption, but is
considered to be potentially available. hence, the maximum amount that
can be absorbed is 14.8 ±3.3.8 %, the sum of the three
compartments (= absorbable dose + SC tape strips).
Note: The author considered the dose fraction
to the upper horny layer of the epidermis (stratum corneum) as being unavailable
for absorption. Hence, the absorbable dose is supposed to consist of
the fractions of the absorbed dose (6.34%) plus the residual fraction bound
to the skin layer after tape stripping (without SC) (1.55%), in total 7.9%
as minimum. The real absorption rate is expected to lie in between.
Given this, contrary to specifications in Report,
Tab. 4, the total unabsorbable dose after 8 h amounts to about 80 % of the
dose applied, with the majority of the remainder accumulated the wash (~59%)
and on the O-ring (~18%), while only some 2% was found in the body wrap. Evaporative
loss is minimal (see charcoal trap).
after 21 days (496 h post-exposure) are less clear: In the first long-term
experiment, the amount absorbed apparently was far too high: The
results from the 21d recovery phase could be refuted as artifact due to
incomplete removal of unabsorbed material from the skin site directly
after the 8h exposure.)
Therefore, a supplemental 21d study was
carried out: However, also the second run may have been confounded, in
this case by the very high dose fraction that adsorbed to the body wrap:
32% already was removed during the cleaning procedure at termination of
exposure period, while only about 22% was left in the skin wash. This
conflicts with the findings of the first 8h-experiment (only 2 % in body
wrap, but 59 % in wash) and raises the suspicion that a substantial part
of the applied dose escaped from potential absorption. Hence, the low
absorption rate of 8.85 % [SD±1.57%]
of the applied dose may be unreliable.
Irrespective of this deficiency, it is evident
that after 21 d practically no radioactivity remained in the treated skin
compartments (see Tab. 4. "Dosed skin" and "Tape strips").
The decrease in label in the horny layer (SC) over 21 days may be attributable
to physiological SC turnover or to skin permeation into the blood system.
It is assumed that all SC-bound material
has been absorbed. The most reliable maximum absorption rate is that one
derived from the fractional distribution of radioactivity in the main 8h study,
in total 14.8 % of the dose applied.
Note: In the previous assessment, the
absorption of 9 % had been adopted as relevant starting point, based on
the 21d supplemental study (see KEMI 2010 - Attached Document). However,
following the caveats outlined above, this value has been skipped by
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