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Short-term toxicity to fish

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Reference
Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
key study
Study period:
from 15 May to 06 August 2012
Reliability:
1 (reliable without restriction)
Qualifier:
according to
Guideline:
OECD Guideline 203 (Fish, Acute Toxicity Test)
Deviations:
yes
Remarks:
A single temperature in the control during the definitive test varied by greater than 1°C from the initial vessel temperature. This was considered not to have a detrimental impact on the study given that the temperature range of 13 to 17°C was maintained.
GLP compliance:
yes (incl. certificate)
Analytical monitoring:
yes
Details on sampling:
Samples for analysis were taken at 0 and 72 hours (freshly prepared media), and 24 and 96 hours (old test media).
Details on test solutions:
Due to the complex and insoluble nature of the test substance (UVCB), a Water Accommodated Fraction (WAF) approach was considered to be the most suitable method of test media preparation.
Test organisms (species):
Oncorhynchus mykiss (previous name: Salmo gairdneri)
Details on test organisms:
TEST ORGANISM
- Common name: trout
- Source: Brow Well Fisheries, Skipton, United Kingdom
- Length at study initiation (length definition, mean, range and SD): 4.9 cm
- Weight at study initiation (mean and range, SD): 1.07 g
- Feeding during test: no

ACCLIMATION
- Acclimation period: at least 12 days
Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Test temperature:
14.2 - 16.6°C (test media)
pH:
7.11 - 7.70
Dissolved oxygen:
at least 9.52 mg/L
Nominal and measured concentrations:
Nominal loading rates (WAF approach) of 0, 0.46, 1.0, 2.2, 4.6, 10 and 22 mg CAE/L in dechlorinated mains water.
Details on test conditions:
TEST SYSTEM
- Test vessel: 12-L glass aquaria
- Material, size, headspace, fill volume: 10 L of media
- No. of organisms per vessel: 7 trouts (fish loading rate 0.75 g/L)
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1

TEST MEDIUM / WATER PARAMETERS
- Chlorine: dechlorinated mains water

OTHER TEST CONDITIONS
- Photoperiod: light cycle of 16 hours

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Mortality
Duration:
96 h
Dose descriptor:
LL50
Effect conc.:
5.09 mg/L
Nominal / measured:
nominal
Conc. based on:
other: WAF
Basis for effect:
mortality
Duration:
96 h
Dose descriptor:
NOELR
Effect conc.:
1 mg/L
Nominal / measured:
nominal
Conc. based on:
other: WAF
Basis for effect:
mortality
Details on results:
During the exposure period, no behaviour and clinical signs were observed up to and including the nominal loading rate of 1 mg/L. The lowest loading rate at which there were significant sub-lethal effects was 2.2 mg/L.

TOC analysis
Based on the results of the TOC analysis, the estimated exposure concentrations of CAE could not be estimated for the lowest loading rate of 0.46 mg/L. For the other loading rates, the estimated exposure concentrations of CAE were: 0.823, 1.50, 3.20, 10.8 and 27.8 mg/L. However, in general, an increase in TOC was observed over the 24-hour dosing periods, considered to be due to biological metabolic process. It was thus considered appropriate to base the results on nominal loading rates only.
Reported statistics and error estimates:
The LL50 values were calculated using linear interpolation (CETIS program v 1.8.6.8)

Table 1     Cumulative mortality for trout exposed for 96 hours to WAFs of CAE

Nominal loading rate

(mg/L)

Mortality (number of trouts) / number of fish initially added

% of mortality at 96 h

24 h

48 h

72 h

96 h

control

0/7

0/7

0/7

0/7

0

0.46

0/7

0/7

0/7

0/7

0

1.0

0/7

0/7

0/7

0/7

0

2.2

0/7

0/7

0/7

0/7

0

4.6

0/7

0/7

0/7

3/7

43

10

0/7

7/7

7/7

7/7

100

22

7/7

7/7

7/7

7/7

100

Validity criteria fulfilled:
yes
Conclusions:
In the conditions of the test and based on nominal loading rates, the 96 hours LL50 of CAE to the rainbow trout Oncorhynchus mykiss was 5.09 mg/L. The 96-hour NOELR value was considered to be 1.0 mg/L.
Executive summary:

In a semi-static acute toxicity test performed according to OECD guideline No.203, trouts (Oncorhynchus mykiss) were exposed for 96 hours in one replicate (7 fish/replicate) to nominal loading rates ranging between 0.46 and 22 mg CAE/L indechlorinatedmains water.A control group was also included.Due to the complex and insoluble nature of the test substance (UVCB), a Water Accommodated Fraction (WAF) approach was considered to be the most suitable method of test media preparation.

Samples of test media were analysed for Total Organic Carbon (TOC), as a measure of the dissolved test substance concentration in new and old test media. In general, an increase in TOC was observed over the 24-hour dosing periods, considered to be due to biological metabolic process. Given these results, it was considered appropriate to base the results on nominal loading rates only.

Based on nominal loading rates, the 96-hour NOELR value was considered to be 1.0 mg/L.The lowest loading rate at which 100% mortality occurred was 10 mg/L. The lowest loading rate at which there were significant sub-lethal effects was 2.2 mg/L.

The 96 hours LL50of CAE to the rainbow trout Oncorhynchus mykiss was 5.09 mg/L.

Description of key information

In the conditions of the test and based on nominal loading rates, the 96 hours LL50 of CAE to the rainbow trout Oncorhynchus mykiss was 5.09 mg/L. The 96-hour NOELR value was considered to be 1.0 mg/L.

Key value for chemical safety assessment

LC50 for freshwater fish:
5.09 mg/L

Additional information