AMMONIUM SULFATE CAS N°: 7783-20-2

OECD SIDS
AMMONIUM SULFATE
After 4 months, 2 control animal and none of the ammonium sulfate treated animals showed
emphysema. After 8 months, the incidence of emphysema in the treated group (2 out of 15 animals)
was equal to that in the control group after 4 months, indicating that the incidence of emphysema
was similar in the treated and control animals.
An increase in the incidence of emphysema in the treated group after 8 months plus 3 months
recovery (4 out of 14 animals) versus the control group (2 out of 13 animals) is, with regard to the
small group size, difficult to interpret, as there were no indications for such an effect from the 4-
and 8 months data.
The same problem is apparent with the data for alveolar birefringence. The value of 53 % (8 out of
15 animals) in the control group after 4 months appears to be extraordinarily high, as physiological
saline should have had no effects in the lungs, and also, because the animals were still quite young.
In contrast, the ammonium sulfate-treated animals had a 0 % incidence of alveolar birefringence at
the same time point. After 8 months, all of the ammonium-sulfate treated animals showed alveolar
birefringence (a phenomenon that is indicative of fibrosis according to the study authors), as
compared with 67 % in the control group. It is surprising that during recovery more control animals
showed this effect, whilst the number of animals with this effect dropped in the ammonium-sulfate
treated group. Overall, the data appear to be very inconsistent. Moreover, it is questionable whether
“alveolar birefringence” is synonymous with “interstitial fibrosis”.
At 4 months, the incidence of bronchiolar hyperplasia in the controls is high (40 %), but it is even
higher in the ammonium sulfate-treated rats (87 %). Surprisingly, no hyperplasia (neither in
controls nor in treated rats) was observed after 8 months, although exposure to the test substance
continued. It remains open as to what exactly was measured, as “all the cell types present in that
area” and the “depth of the epithelium” were included in the measurements. A scientific evaluation
of the reported findings is therefore impossible.
The mean and median chord lengths were statistically significantly increased after 4 months and
after recovery but only numerically after 8 months, also indicating a great variation in these finding.
Nonciliated epithelial cell counts were increased after 4 and 8 months but not after recovery. In
conclusion, it remains open whether the results discussed above are related to a bad health status of
the animals, or to rather unspecific or inappropriate investigation methods. Nevertheless, it is
evident that the findings cannot clearly be attributed to the test substance and that they are of
limited relevance for the toxicological assessment of ammonium sulfate.
Exposure of rabbits for 14 days, 2 h/d to 2 mg ammonium sulfate/m 3 did not result in a change in
respiratory region clearance (Schlesinger, 1989).
Dermal
There were no dermal studies available.
Oral
Fischer 344 rats (10 rats/sex/dose) were exposed during 13 weeks to diets containing 0, 0.38, 0.75,
1.5 or 3 % ammonium sulfate (corresponding to 0, 222, 441, 886, 1792 mg/kg bw/day in males and
to 0, 239, 484, 961, 1975 mg/kg bw/day in females) No substance-related changes between the
treatment groups and controls were found in body weights, haematology and serum parameters, or
in the histological examinations (brain, heart, lung, liver, kidney, adrenal gland, spleen, testes,
thymus) Relative and absolute kidney weights were increased in both male and female animals in
the highest dose group. The authors did not judge this as adverse, because there were no
histopathologic effects seen in the kidneys. The relative testes weight was significantly increased at
all doses, but no histological effects were found. Male animals of the highest dose group exhibited
22
UNEP PUBLICATIONS