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Short-term toxicity to fish

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Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
From 1954 to 1989
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The EU RAR summarises the results of a number of fish acute studies which, individually, have limitations regarding study design and reliabilty. However the results of these studies when taken as a whole, provide an adequate assessment of acute toxicity to fish. The data are considered to fulfil the criteria laid down in Annex XI to Regulation 1907/2006: adequate for classification and labelling, adequate coverage of key parameters (lethality), exposure duration comparable or longer that Article 13(3) methods (96 hours), adequate documentation provided: EU RAR, of which parts have been copied to this endpoint record. Reliability for endpoint also increased based on test results from several species.
Qualifier:
no guideline followed
Guideline:
other: range of studies
Principles of method if other than guideline:
Several studies, collectively, provide a weight-of-evidence to address the acute toxicity endpoint. The methods include the appropriate endpoints (lethality and sublethal effects) and duration (equal to 96 hours exposure). Results from more species than recommended have been reported and hence provide an adequate representation of acute toxicity to fish.
GLP compliance:
no
Analytical monitoring:
yes
Details on sampling:
Various sampling procedures based on multiple studies
Vehicle:
no
Details on test solutions:
various test media prepared based on multiple studies in freshwater and salt water.
Test organisms (species):
other: Range of species tested
Details on test organisms:
Range of species tested
Test type:
other: Range of test designs used
Water media type:
freshwater
Limit test:
no
Remarks on exposure duration:
Range used from several studies
Post exposure observation period:
None reported
Hardness:
Range used from several studies
Test temperature:
Range used from several studies
pH:
Range used from several studies
Dissolved oxygen:
Range used from several studies
Salinity:
Range used from several studies
Nominal and measured concentrations:
Range used from several studies
Details on test conditions:
Range used from several studies
Reference substance (positive control):
not specified
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
13 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Basis for effect:
other: see table below
Remarks on result:
other: see table below
Details on results:
See any other information below.
Sublethal observations / clinical signs:

The results of the acute fish toxicity studies evaluated in the EU RAR are summarised below:

Species

Endpoint

Value (mg/l)

Reference

Freshwater

Brachydanio rerio

96-hour LC50

58.5

Bellavere and Gorbi (1981)

Carrasius auratus

96-hour LC50

37.5

Pickering and Henderson (1966)

Channa punctatus

96-hour LC50

45.2

Saxena and Parashari (1983)

Colisa fasciatus

96-hour LC50

20.8c

Srivastava et al. (1979)

Ictalurus punctatus

24-hour LC50

58

Cairns Jr. et al (1978)

Lebistes reticulatus  

96-hour TLm

30

Pickering and Henderson (1966)

Lepomis macrochirus

96-hour LC50
48-hour TLm

96-hour LC50

110

213a

120b

Trama and Benoit (1960)

Turnbull et al. (1954)

Cairns Jr. and Scheier (1958)

Morone saxitalis

96-hour LC50

28b

Palawski et al. (1985)

Notemigonus crysoleucas

96-hour LC50

55

Hartwell et al. (1989)

Oncorhynchus mykiss

96-hour LC50

63.6

69a

13d

Brown et al. (1985)

Benoit (1976)

Van Der Putte et al (1981b)

Pimephales promelas

96-hour TLm
96-hour LC
50

96-hour TLm

17.6

33.2a

45.6b

Pickering and Henderson (1966)

Benoit (1976)

Pickering and Henderson (1966)

Salvelinus fontinalis  

96-hour LC50

59

Benoit (1976)

Saltwater

Alburnus alburnus*

96-hour LC50

84.8

Lindén et al. (1979)

Chelon labrosus

48-hour LC50

47.2

Taylor et al. (1985)

Citlerichthys stigmaeus

96-hour LC50

30

Mearns et al. (1976)

Cyprinodon variegates

96-hour LC50

25

21.4b

Jop et al. (1987)

Dorn et al. (1987)

Gasterosteus aculcatus*

96-hour LC50

33

35b

Jop et al. (1987)

Limanda limanda

96-hour LC50

47

Taylor et al. (1985)

Validity criteria fulfilled:
yes
Conclusions:
Based on a review of existing fish data from the EU RAR, an acceptable assessment of acute toxicity was achieved.
Executive summary:

Based on a review of existing fish data from the EU RAR, an acceptable assessment of acute toxicity was achieved.

The acute toxicity of chromium (VI) to fish appears to be dependent on the water hardness and also pH. Higher toxicity has generally been seen in soft water and at more acidic pHs, particularly those <6.5. This dependence appears to follow a similar pattern to the uptake of chromium (VI) by fish (see Section 3.1.1.2.4), where it has been postulated that at lower pHs, the main form of chromium (VI) in solution is the monovalent HCrO4 - ion, which has been postulated as having a higher mobility across cell membranes than the divalent chromium (VI) oxyanions found at higher pH.

For some fish species, toxicity data are available for more than one of the chromium (VI) compounds included in this assessment. The available information indicates that, when expressed on a total chromium concentration, there are no significant differences between the toxicity of sodium chromate, sodium dichromate and potassium dichromate (allowing for differences in water properties). This is as would be expected if the equilibria between the chromate and dichromate anions are established in the test medium. Little information is available for ammonium dichromate and chromic acid, but it would be expected that their toxicity would be similar to that of the other chromates/dichromates, when expressed on a total chromium concentration basis.

Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
key study
Study period:
not specified
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
no guideline followed
Principles of method if other than guideline:
Static experiments in which Danio rerio fish were exposed to 7 concentrations of chromium(VI) were run for 96 hours. All tests were carried out in dilution water (distilled water supplemented with salts) and at a constant temperature (20°C). Oxygen saturation and pH were checked during each experiment and did not decrease significantly until the end of the test. In the analysis the salt potassium dichromate was used. Mortality was checked every 24 hours.
GLP compliance:
not specified
Remarks:
before GLP was standard
Analytical monitoring:
yes
Vehicle:
not specified
Details on test solutions:
not given
Test organisms (species):
Danio rerio (previous name: Brachydanio rerio)
Details on test organisms:
TEST ORGANISM
- Common name: zebrafish
- Source: commercial, aquarist shops
- Length at study initiation (length definition, mean, range and SD): 3.5 +/- 0.5 cm

ACCLIMATION
- Acclimation period: 30 days
- Health during acclimation (any mortality observed): The fish were used only if, at the end of acclimation period, they did not exhibit malformations or apparent signs of stress.
Test type:
static
Water media type:
freshwater
Remarks:
dilution water prepared from distilled water
Limit test:
no
Total exposure duration:
96 h
Hardness:
100 mg/L as CaCO3
Test temperature:
20 °C
pH:
7.8
Dissolved oxygen:
always close to saturation level, >=90%
Nominal and measured concentrations:
not specified
Details on test conditions:
TEST SYSTEM
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: distilled water mixed with six salts (please refer to section "Any other information on materials and methods incl. tables" for further information), aerated for 24 hours
- Culture medium different from test medium: no

EFFECT PARAMETERS MEASURED (with observation intervals if applicable):
- Mortality assessed every 24 hrs

TEST CONCENTRATIONS
- Range finding study/Test concentrations: Preliminary tests were made and for each of the toxicants a set of seven concentrations was determined in the range from the highest not causing mortality to the lowest causing 100% mortality.
Key result
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
58.5 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Basis for effect:
mortality (fish)
Duration:
72 h
Dose descriptor:
LC50
Effect conc.:
58.5 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Basis for effect:
mortality (fish)
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
67 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Basis for effect:
mortality (fish)
Duration:
24 h
Dose descriptor:
LC50
Effect conc.:
96 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Basis for effect:
mortality (fish)
Duration:
12 h
Dose descriptor:
LC50
Effect conc.:
128 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Basis for effect:
mortality (fish)
Duration:
8 h
Dose descriptor:
LC50
Effect conc.:
183 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Basis for effect:
mortality (fish)
Reported statistics and error estimates:
The LC50 have been computed using the method of Litchfield and Wilcoxon (1949).
Validity criteria fulfilled:
not specified
Conclusions:
An acute toxicity study was performed with the zebrafish (Brachydanio rerio) exposed to potassium dichromate for a test duration of 96 h using static test conditions. The study is well documented and meets generally accepted scientific principles, wherefore it is considered to be acceptable for the assessment of the acute toxicity of the registered substance to fish.
Under the conditions used for the test the toxicity of chromium to zebrafish increased over time shown by a constant decrease in LC50 values until 72 hours exposure time. As the standard deviations are approx. equal at all control times, the results can be considered reliable. Based on the obtained results, the 96h LC50 was determined to be nominal 58.5 mg/L. Thus, the obtained LC50 values of chromium(VI) to B. rerio are generally in agreement with those found by other authors.
Executive summary:

The acute toxicity of the test substance to fish was investigated in the above study. Brachydanio rerio (zebra fish) was used as test organism and exposed to seven nominal test concentrations causing 0 - 100% effects for 96 hours of test duration under static test conditions. A control was running in parallel containing dilution water only. The test was carried out at a temperature of 20°C, with a pH of 7.8 and an oxygen concentration above the saturation concentration ( ≥ 90% ASV) throughout the test. Based on the obtained results, the 96h LC50 was determined to be nominal 58.5 mg/L.

Description of key information

1) Key_ Short-term toxicity to fish by summary of data from European Union Risk Assessment Report: chromium trioxide, sodium chromate, sodium dichromate, ammonium dichromate and potassium dichromate

3rd. Priority List; Volume 53: LC50 (96h) = 13 - 120 mg/L (nominal) for several species from various studies

2) Key_Short-term toxicity to fish: LC50(96h) = 58.8 mg/L (nominal) for Potassium dichromate exposed to Brachydanio rerio (static, freshwater, no guideline followed)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish
Dose descriptor:
LC50
Effect concentration:
13 mg/L

Additional information

1) Based on a review of existing fish data from the EU RAR, an acceptable assessment of acute toxicity was achieved.

The acute toxicity of chromium (VI) to fish appears to be dependent on the water hardness and also pH. Higher toxicity has generally been seen in soft water and at more acidic pHs, particularly those <6.5. This dependence appears to follow a similar pattern to the uptake of chromium (VI) by fish (see Section 3.1.1.2.4), where it has been postulated that at lower pHs, the main form of chromium (VI) in solution is the monovalent HCrO4 - ion, which has been postulated as having a higher mobility across cell membranes than the divalent chromium (VI) oxyanions found at higher pH.

For some fish species, toxicity data are available for more than one of the chromium (VI) compounds included in this assessment. The available information indicates that, when expressed on a total chromium concentration, there are no significant differences between the toxicity of sodium chromate, sodium dichromate and potassium dichromate (allowing for differences in water properties). This is as would be expected if the equilibria between the chromate and dichromate anions are established in the test medium. Little information is available for ammonium dichromate and chromic acid, but it would be expected that their toxicity would be similar to that of the other chromates/dichromates, when expressed on a total chromium concentration basis.

2) The acute toxicity of the test substance to fish was investigeted in the above study. Brachydanio rerio (zebra fish) was used as test organism and exposed to seven nominal test concentrations causing 0 - 100% effects for 96 hours of test duration under static test conditions. A control was running in parallel containing dilution water only. The test was carried out at a temperature of 20°C, with a pH of 7.8 and an oxygen concentration above the saturation concentration ( ≥ 90% ASV) throughout the test. Based on the obtained results, the 96h LC50 was determined to be nominal 58.8 mg/L.