Vanadate(1-), oxo[phosphato(3-)-.kappa.O]-, hydrogen, hydrate (2:2:1)

Toxicity to aquatic algae and cyanobacteria

Description of key information

The substance is acutely toxic to algae.

The lowest 72-h ErC50 (2907 µg V/L, meas.) and ErC10 values (716 µg V/L, meas.) for growth rate of the green alga Scenedesmus subspicatus were observed for V2O5 flakes (Mitterer, 1999; Klimisch 2).

Corrected for the molecular weight of vanadylhydrogenphosphate-hemihydrate (CAS no. 93280-40-1): 72-h ErC50 = 9888 µg/L; 72-h ErC10 = 2435 µg/L

Key value for chemical safety assessment

EC50 for freshwater algae:

9 888 µg/L

EC10 or NOEC for freshwater algae:

2 435 µg/L

Additional information

Data on the long-term toxicity of vanadylhydrogenphosphate-hemihydrate (CAS no. 93280-40-1) to aquatic algae are not available; therefore, a read-across approach to structurally similar pentavalent vanadium substances was performed.

Three reliable guideline studies were performed with three different pentavalent vanadium substances by Mitterer (1999). The test species was Desmodesmus subspicatus. The tests were performed according to OECD 201 and EU method C.3 under GLP conditions. The test concentrations were analytically verified by monitoring the vanadium concentrations in the medium. The test duration was 72 hours. Biomass and growth rate were observed. The lowest effect values were recorded for divanadium pentaoxide (CAS 1314-62-1).

Table: Observed endpoints for Desmodesmus subspicatus (measured)

Test substance	report no.	Endpoint	Concentration [µg/L]	Remark
CAS 1314-62-1	11920-99	72-h ErC10	716	Growth rate; Key study
CAS 1314-62-1	11920-99	72-h ErC50	2907	Growth rate; Key study
CAS 1314-62-1	11920-99	72-h NOEC	16.8	Biomass; Key study
CAS 1314-62-1	11920-99	72-h EbC50	989	Biomass; Key study
CAS 13718-26-8	11921-99	72-h ErC10	4342	Growth rate; Supporting study
CAS 13718-26-8	11921-99	72-h ErC50	7619	Growth rate; Supporting study
CAS 13718-26-8	11921-99	72-h NOEC	75	Biomass; Supporting study
CAS 13718-26-8	11921-99	72-h EbC50	2177	Biomass; Supporting study
CAS 12207-63-5	11922-99	72-h ErC10	1796	Growth rate; Supporting study
CAS 12207-63-5	11922-99	72-h ErC50	3865	Growth rate; Supporting study
CAS 12207-63-5	11922-99	72-h NOEC	30	Biomass; Supporting study
CAS 12207-63-5	11922-99	72-h EbC50	1162	Biomass; Supporting study

 

Further information are available for CAS 13718-26-8. Miramand & Unsai (1978) published data on the toxicity of the substance to marine algae. However, the tests did not followed a standard guideline and the test method was poorly described. In addition, no statistics were provided. The test concentrations were not monitored. The exposure period (15 days) and the endpoint are not relevant (mortality) for algae. Therefore, the information are not reliable and were disregarded.

A study with Pseudokirchneriella subcapitata investigated the effect of CAS 65232-89-5 (E-326 catalyst). The study was performed according to OECD 201 under GLP (BASF SE, 1998; report no. HUT004/982383). The study is considered as supporting information.

For the assessment of the toxicity of vanadylhydrogenphosphate-hemihydrate (CAS no. 93280-40-1), the effect values based on the vanadium concentration must be corrected for the molecular weight of vanadylhydrogenphosphate-hemihydrate (29.4% V). Corrected for the molecular weight of vanadylhydrogenphosphate-hemihydrate (CAS no. 93280-40-1): 72-h ErC50 = 9888 µg/L (= 2907 µg V/L); 72-h ErC10 = 2435 µg/L (= 716 µg V/L).

It can be concluded that the substance is acutely toxic to algae.