Barium chromate

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1973 - 1989

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: See 'Remarks'

Remarks:

The EU RAR summarises the results of a number of acute invertebrate toxicity studies which, individually, have limitations regarding study design and reliability. However, the results of these studies when taken as a whole, provide an adequate estimate of the acute 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 (lethality), exposure duration comparable or longer that Article 13(3) methods ( 48 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.

Data source

Reference

Reference Type:

review article or handbook

Title:

Unnamed

Year:

2005

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 support the acute toxicity

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Chromium

EC Number:

231-157-5

EC Name:

Chromium

Cas Number:

7440-47-3

Molecular formula:

Cr

IUPAC Name:

chromium

Specific details on test material used for the study:

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

Details on test solutions:

Various test media prepared based on multiple studies in freshwater and salt water

Test organisms

Test organisms (species):

other: Range of species tested

Study design

Test type:

other: Range of test designs used

Test conditions

Hardness:

Range used from multiple studies

Test temperature:

Range used from multiple studies

pH:

Range used from multiple studies

Dissolved oxygen:

Range used from multiple studies

Salinity:

Range used from multiple studies

Details on test conditions:

Range used from multiple studies

Results and discussion

Effect concentrations

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

>= 1.2 mg/L

Any other information on results incl. tables

Species	Method	Chemical tested	Hardness (mg/l)	Endpoint (mg Cr/l)	Reference
INVERTEBRATES - freshwater - short-term (48-96h) studies
Crustaceans
Asellus aquaticus(sowbug)	-	Chromic chloride	-	48h-EC50= 937 96h-EC50= 442	DOSE, 1993
Crangonyx pseudogracilis (amphipod)	-	Chromic chloride		48h-EC50= 388 96h-EC50= 291	DOSE, 1993
Daphnia magna(water flea)	-	Chromic chloride	-	24h-EC50= 111	DOSE, 1993
Daphnia magna(water flea)	S; N	Chromic chloride	-	EC50= 1.2	Anderson, 1948
Daphnia magna(water flea)	S; M	Chromic nitrate	52	EC50= 16.8	Chapman et al (unpublished)
			92	EC50= 27.4
			110	EC50= 26.3
			195	EC50= 51.4
			215	EC50= 58.7
Gammarussp. (amphipod)	S; M	-	50	EC50= 3.2	Rehwoldt et al, 1973
Orconectes limosus (crayfish)	S; M	Chromic chloride	-	EC50= 6.6	Boutet and Cheismemartin, 1973
Insects
Caddis fly (unidentified)	S; M	-	50	EC50= 58	Rehwoldt et al, 1973
Chironomussp. (midge)	S; M	-	50	EC50= 11.0	Rehwoldt et al, 1973
Damselfly (unidentified )	S; M	-	50	EC50= 43.1	Rehwoldt et al, 1973
Ephemarella subvaris (mayfly)	S; N	Chromic chloride	44	EC50= 2.0	Warnick and Bell, 1969
Hydropsyche bettoni(caddis fly)	S; M	Chromic chloride	44	EC50= 64.0	Warnick and Bell, 1969
Molluscs
Amnicolasp. (snail; embryo)	S; M	-	50	EC50= 12.4	Rehwoldt et al, 1973
Amnicolasp. (snail; adult)	S; M	-	50	EC50= 12.4	Rehwoldt et al, 1973
Annelids
Neissp.(worm)	S; M	-	50	EC50= 9.3	Rehwoldt et al, 1973
INVERTEBRATES - saltwater - short-term (48-96h) studies
Crassostrea virginica (eastern oyster)	S; U	Chromic chloride		EC50= 10.3	Calabrese et al, 1973
Ophtyotrocha diadema (polychaete worm)	S	Chromic chloride	32‰	48h-EC50= 100	Parker, 1984

Applicant's summary and conclusion

Conclusions:

From the available data, it can be seen that chromium (III) appears to be less toxic than chromium (VI) in waters of medium hardness (>50 mg CaCO3). In lower hardness waters the acute toxicity increases; there are also indications that NOEC values decrease with decreasing hardness. There are insufficient data to carry out an HC5 calculation for chromium (III). From the freshwater data reported in Appendix F, long-term NOEC values are 0.05 mg/l for fish and 0.047 mg/l for invertebrates, and >2 mg/l for algae (although an EC50 of 0.32 mg/l is reported for another species). The fish and invertebrate values relate to hardness levels of 26 and 52 mg/l respectively. Applying an assessment factor of 10 to the lowest available NOEC gives a tentative PNEC for chromium (III) of 4.7 μg/l for soft water. This is similar to that derived for chromium (VI) above, but the two values are not directly comparable as they are based on very different data sets. However, this may indicate that in low hardness waters the two forms may not be very different in effect. The NOEC from the same invertebrate study at a hardness of 100 mg/l was 0.129 mg/l, which would give a ‘PNEC’ of 13 μg/l. The data indicate that chromium (III) may have reduced toxicity at greater hardness levels, but as with chromium (VI) the evidence is limited (these comments relate to chronic toxicity).
The PNEC is at the lower end of the range of published criteria/standards for the protection of aquatic life. For example, the UK Environmental Quality Standard for total chromium in freshwater ranges from 5 to 50 μg/l (dependent on water hardness) and in saltwater it is 15 μg/l.
It should also be noted that the PNEC for chromium (III) refers to the dissolved water concentration. In laboratory tests, water soluble forms of chromium (III) have generally been used. However, in the environment, chromium (VI) is likely to be reduced to forms of chromium (III) with limited water solubility, which will be associated mainly with the particulate (sediment and suspended matter) phases of the water compartment.
In summary, the PNEC values for the surface water compartment are 3.4 μg/l for chromium (VI) and 4.7 μg/l for chromium (III).