N-(1,3-Dimethylbutyl)-N

OECD SIDS
N-(1,3-DIMETHYLBUTYL)-N´-PHENYL-1,4-PHENYLENEDIAMINE
4. ECOTOXICITY ID: 793-24-8
DATE: 11.05.2005
contained less than 0.05 mg/l total NH3. On page 8 of the study it is
reported that the controls contained between 0.8-1.8 mg/l "Ammonia" and
Santoflex 13 incubation solutions contained between 0.6-3.2 mg/l
"Ammonia". On page 6 of the study it is stated that "the ammonia
concentrations were below the toxic level" and a 592 pages study is cited
without giving additional information on how the conclusion was drawn.
Even if "total NH3" including NH4 is meant on page 8, the concentration is
too high and might have led to reactions above a treshold due to additional
ammonia released from the degrading test substance.
According to OECD Guideline 305 (flow through fish test for
bioconcentration measurement) and 210 (fish early live stage) dilution
water is only acceptable as long as the unionised ammonia concentration
is below 1 µg/l.
Since the pKa (ammonium) is approximately 9.25, the unionised ammonia
concentration exceeded 1 µg/l at physiological pH. According to the
following equation, free ammonia exceeded the acceptable concentration
of these guidelines by 1-2 orders of magnitude: % unionised ammonia of
total ammonia = 100 / (1 + antilog (pKa -pH)) [pKa = 0.09018 + 2729.92
/Temperature in Kelvin].
- Although it was anounced by the authors that the acetone concentrations
are reported in appendix 1 of the study, no acetone concentrations could
be found.
- It is not explained by the authors why the controls contained
approximately half of the 6PPD concentration of the lowest tested 6PPD
concentration
- Limit(s) of detection/quantification not clearly reported
Result : Day of exposure/nominal LC50 [mg/l] (estimated concentration [mg/l]
derived from measured values as far as available) for endpoint mortality
2/2
3/0.48
4/0.45 (0.26)
5/0.41
6-8/0.35
9-10/0.32
11-13/0.30
14/0.27
15/0.24
16/0.21
17/0.20
18/0.18
19-21/0.17
22-25/0.16
26-28/0.15
The authors concluded that the lethal threshold had not been reached after
28 days. They also stated that Santoflex 13 appeared to have cumulative
toxicity.
Test condition : Test fish: Obtained from Fender's Fish Hatchery, Brady, Nebraska;
acclimated for at least 14 days prior to testing; fed with standard
commercial fish food (Rangen's) in amounts of 3 % of their body weight;
mean weight 1.3 g; mean standard length 40.1 mm; qualitiy check with
Antimycin A, done prior to test, revealed fish were in good condition;
selection for test by random assignment, 30 fishs/aquarium
Summary on concentrations of test substance (mg/l):
nominal measured (mean)
0.066 0.024
0.12 0.034
0.23 0.089
0.45 0.26
1.0 0.92
Concentrations of test substance in detail (mg/l):
78
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