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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:
1993
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The study was given a reliability rating of 1 because it followed a standard test guideline, which describes a procedure to evaluate this endpoint, and the results were reviewed for reliability and assessed as valid. The study was also conducted under GLP.
Qualifier:
according to guideline
Guideline:
OECD Guideline 203 (Fish, Acute Toxicity Test)
Deviations:
no
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
However, analysis of the test media was restricted to the media produced at higher loading rates. All media produced at loading rates less 2mg/L
were not analysed because they were below the limit of determination (2.5 mg/L) of the analytical method.
Vehicle:
no
Details on test solutions:
Individual treatment solutions were prepared as Water Accommodated Fractions (WAFs). This included adding test substance to glass vessels,
which contained laboratory dilution water and mixing for approximately 24 hours with a magnetic stirrer to produce a series of geometrically-
spaced loading rates (mg/L). After mixing, the WAFs were allowed to settle for an hour. The aqueous phase was then drawn off and transferred
to 11 litre full-volume, spherical glass vessels which were completely filled. An additional vessel received dechlorinated water only and
served as a control.

Test organisms (species):
Oncorhynchus mykiss (previous name: Salmo gairdneri)
Details on test organisms:
O.mykiss fingerlings were supplied by Exmoor Trout Farm, North Molton, Devon, UK; mean wt. = 0.96 g; mean total length = 4.4 cm.
Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Hardness:
Water hardness during the test ranged from 280 - 314 mg/L as CaCO3.
Test temperature:
Test temperature was 15 – 16 ºC with a 16 h : 8 h light : dark lighting regime.
pH:
The pH ranged from 6.8 to 8.5 during the test.
Dissolved oxygen:
Dissolved oxygen = 9.4 to 10.5 mg/L for "new" solutions and 7.5 to 9.3 mg/L for "old" solutions.
Salinity:
freshwater
Nominal and measured concentrations:
Nominal treatment levels were: control, 0.2, 0.7, 2.0, 5.0, 17 and 50 mg/L. Analysis confirmed concentrations at t=0 of 4.3, 7.5 and 9.5 mg/L for the
nominal loading rates of 5.0, 17 and 50 mg/L, respectively. As there were fish mortalities at these loading rates, no further samples were available
for analysis. All media produced at loading rates less than 2mg/L were not analysed because they were below the limit of determination (2.5 mg/L)
of the analytical method.
Details on test conditions:
7 fish were placed in each test vessel, which was then sealed with a glass plate, ensuring that all air was excluded. New WAFs for each treatment
were prepared as described above for each daily renewal. Surviving fish were transferred to the vessel containing freshly prepared WAF. The fish
were not fed during the test.

Test temperature was 15 – 16 ºC with a 16 h : 8 h light : dark lighting regime. Dissolved oxygen = 9.4 to 10.5 mg/L for "new" solution and 7.5 to
9.3 mg/L for "old" solution. The pH ranged from 6.8 to 8.5 during the test. Water hardness during the test ranged from 280 - 314 mg/L as CaCO3.
The water used was harder than the preferred range (10 - 250 mg/L) . However, the hardness measured is normal for this laboratory and does
not affect fish survival.
Reference substance (positive control):
no
Key result
Duration:
96 h
Dose descriptor:
LL50
Effect conc.:
>= 2 - <= 5 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality (fish)
Details on results:
See Table Below
Reported statistics and error estimates:
Statistical Method: None required

Loading rates causing a 50% effect were determined by visual inspection of the data. They are expressed as being within a range bounded by
loading rates that were tested. This is considered more appropriate for test materials that are mixtures of substances of different solubilities
than is an interpolative statistical technique
Sublethal observations / clinical signs:

Nominal Loading Measured Fish Total Mortality
Conc. (mg/l) Conc. (mg/l) (@ 24, 48, 72, 96 hrs)
     
Control Control 0, 0, 0, 0
0.2 < LoD 0, 0, 0, 0
0.7 < LoD 1, 1, 1, 1
2.0 < LoD 0, 0, 0, 0
5.0 4.3 0, 7, 7, 7
17.0 7.5 7, 7, 7, 7
50.0 9.5 7, 7, 7, 7
Validity criteria fulfilled:
yes
Conclusions:
Water accommodated fractions of hydrocarbons, C10, aromatics, >1% naphthalene, produced a 96-hour LL50 value between 2 and 5 mg/L with rainbow trout, Oncorhynchus mykiss.
Executive summary:

Water accommodated fractions of hydrocarbons, C10, aromatics, >1% naphthalene, produced a 96-hour LL50 value between 2 and 5 mg/L with rainbow trout, Oncorhynchus mykiss.

Description of key information

Water accommodated fractions of hydrocarbons, C10, aromatics, >1% naphthalene, produced a 96-hour LL50 value between 2 and 5 mg/L with rainbow trout, Oncorhynchus mykiss. In a supporting study, water accommodated fractions of hydrocarbons, C10, aromatics, >1% naphthalene, produced a 96-hour LL50 value of 14 mg/L with rainbow trout, Oncorhynchus mykiss.

Key value for chemical safety assessment

Additional information

Water accommodated fractions of hydrocarbons, C10, aromatics, >1% naphthalene, produced a 96-hour LL50 value between 2 and 5 mg/L with rainbow trout, Oncorhynchus mykiss.