Methylphosphonic acid

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Qualifier:

no guideline followed

Principles of method if other than guideline:

No details on materials and methods provided

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

not specified

Test type:

not specified

Water media type:

not specified

Duration:

14 d

Dose descriptor:

EC50

Effect conc.:

17.805 mg/L

Conclusions:

Th 14d EC50 was reported to be 17.805 mg/L.

Description of key information

Acute toxicity for freshwater algae Pseudokirchneriella subcapitata (growth rate):
72h-EC50 = 43.1 mg MPAAU/L 
72h-EC10 =  13.5 mg MPAAU/L
72h-NOEC = 3.2 mg MPAAU /L

Key value for chemical safety assessment

EC50 for freshwater algae:

43.1 mg/L

EC10 or NOEC for freshwater algae:

13.5 mg/L

Additional information

A valid algal growth inhibition study (Kley 2012) with read across substance MPAAU revealed following results for growth rate: 72h-EC50 = 43.1 mg/L, 72h-EC10 = 13.5 mg/L, 72h-NOEC value = 3.2 mg/L. The algae therefore has been to be the most sensitive of the tested freshwater organisms.

The algal growth inhibition study of Williams 1987 was conducted with the target substance itself. However, the review article of Munro et al. (1999) is giving no further information than the mere result. But these data only are known from this single secondary literature source, it is furthermore not possible to verify the correctness of the data by a second independent data source. Because of this, further attempts were undertaken to retrieve the original study report from U.S. military web services (USCEHR, NTIS), but unfortunately without success. With no further clarification on data reliability possible, this renders the reliability of the acute algal growth inhibition study of Williams (1987) as not assignable (Klimisch 4).