Potassium chromate

Long-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The EU RAR summarises the results of a number of aquatic invertebrate toxicity 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 chronic toxicity to aquatic invertebrates. 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 (survival, reproduction and growth), exposure duration comparable or longer that Article 13(3) methods, 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.

Data source

Reference

Reference Type:

review article or handbook

Title:

European Union Risk Assessment Report: chromium trioxide, sodium chromate, sodium dichromate, ammonium dichromate and potassium dichromate

Author:

European Chemicals Bureau

Year:

2005

Bibliographic source:

3rd. Priority List; Volume 53

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Several studies, collectively, provide a weight-of-evidence to address the endpoint of chronic toxicity

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Chromium trioxide

EC Number:

215-607-8

EC Name:

Chromium trioxide

Cas Number:

1333-82-0

IUPAC Name:

1333-82-0

Constituent 2

Reference substance name:

Potassium dichromate

EC Number:

231-906-6

EC Name:

Potassium dichromate

Cas Number:

7778-50-9

Molecular formula:

Cr2H2O7.2K

IUPAC Name:

sodium dichromate

Constituent 3

Reference substance name:

Sodium dichromate

EC Number:

234-190-3

EC Name:

Sodium dichromate

Cas Number:

10588-01-9

Molecular formula:

Cr2Na2O7

IUPAC Name:

sodium dichromate

Details on test material:

For some invertebrates, toxicity data is available for more than one of the chromium (VI) compounds included in this assessment. The limited 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.

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Various sampling procedures based on multiple studies

Test solutions

Vehicle:

no

Details on test solutions:

Various test media prepared based on multiple studies

Test organisms

Test organisms (species):

other: range of species tested

Study design

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

Test conditions

Hardness:

Range from several studies

Test temperature:

Range from several studies

pH:

Range from several studies

Dissolved oxygen:

Range from several studies

Salinity:

Not applicable

Nominal and measured concentrations:

Range from several studies

Details on test conditions:

Range from several studies

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Remarks on result:

other: See "Any other information on results incl. tables" below.

Any other information on results incl. tables

The results of the chronic aquatic invertebrate toxicity studies evaluated in the DAR are summarised below.

Species	Endpoint	Value (mg/L)	Reference
Crustacea
Ceriodaphnia dubia	7-day NOEC (survival) 7-day NOEC (reprod)	8.4 4.7	De Graeve et al. (1992) De Graeve et al. (1992)
Daphnia carinata	NOEC (reprod)	50	Hickey (1989)
Daphnia magna	21-day NOEC (mortality) 21-day NOEC (reprod) 21-day NOEC (mortality) 21-day NOEC (reprod) 21-day NOEC (survival) 21-day NOEC (growth) 21-ay NOEC (yield) 14-day NOEC (reprod) 14-day NOEC (reprod)	18 18 35 35 200 60 350 25 0.5a	Kuhn et al. (1989) Kuhn et al. (1989) Sloof and Canton (1983) Sloof and Canton (1983) Van Leeuwen et al. (1987) Van Leeuwen et al. (1987) Van Leeuwen et al. (1987) Hickey (1989) Elnabarawy et al. (1986)
Coelenterate
Hydra littoralis	11-day NOEC (reprod)	35	Dannenberg (1984)
Hydra oligactis	21-day NOEC (growth)	1,100	Sloof and Canton (1983)
Insect
Culex pipiens	25-day NOEC (survival) 25-day NOEC (development)	1,100 1,100	Sloof and Canton (1983) Sloof and Canton (1983)
Mollusc
Lymnaea stagnalis	40-day NOEC (reprod) 40-day NOEC (mortality) 7-day NOEC (hatchability)	110 3,500 350	Sloof and Canton (1983) Sloof and Canton (1983) Sloof and Canton (1983)

Results are from tests with potassium dichromate except for a - sodium dichromate. All concentrations as Cr.
De Graeve et al., (1992): this paper reported the results of a ring test, in which 18 determinations of the NOEC values were made.   The values in the table here are the geometric mean of the NOEC values reported for each endpoint.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Based on a review of existing data, an adequate assessment of the chronic toxicity of Cr(VI) to aquatic invertebrates has been achieved.

Executive summary:

From a review of the long-term effects of potassium and sodium dichromate on aquatic invertebrates, a range of results is presented based on several endpoints and durations of exposure. As well as effects on survival and reproduction of invertebrates, sublethal effects of exposure to chromium (VI) have been reported. Adult grass shrimp, Palaemonetes pugio, were exposed to levels of chromium (VI) (as sodium chromate) ranging from 0.5 to 4.0 mg/l over 28 days. Approximately 41% of surviving shrimp possessed cuticular lesions, usually associated with articulations of the appendages and abdomen, after exposure to 0.5 mg/l. Increasing exposure

concentrations lead to a proportionate increase in the loss of limbs such that nearly 50% of limbs were lost at the highest exposure concentration. It was proposed that the organisms experienced chromium-induced exoskeletal deficiencies resulting in a viaduct for pathogenic organisms and direct chromium influx that perpetuated lesion development (Doughtie et al., 1983).