Bisguanidinium phosphate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

please refer to Read Across Statement attached in Section 13

Reason / purpose for cross-reference:

read-across source

Parameter:

% degradation (CO2 evolution)

Value:

7.5

St. dev.:

0.71

Sampling time:

29 d

Remarks on result:

other: Average of 2 test bottles

Details on results:

- Theoretical CO2 production: The TOC concentration of the 1 g/L Guanidine phosphate (1:1) solution was determined to be 77.95 mg/L. The ThCO2 of guanidine phosphate (1:1) was calculated to be 0.29 mg CO2/mg.

- Biodegradation: The relative biodegradation values calculated from the measurements performed during the test period revealed no significant biodegradation of guanidine phosphate (1:1). In the toxicity control more than 25% biodegradation occurred within 14 days (33%, based on ThCO2). Therefore, the test substance was assumed not to inhibit microbial activity.

- Acceptability of the test:
The positive control substance was biodegraded by at least 60% (81% was observed) within 14 days.
The difference of duplicate values for %-degradation of the test substance was always less than 20%.
The total CO2 release in the blank at the end of the test did not exceed 40 mg/L (51 mg CO2per 2 litres of medium, corresponding to 25 mg CO2/L).
The Inorganic Carbon content (IC) of the test substance (suspension) in the mineral medium at the beginning of the test was less than 5% of the Total Carbon content (TC). Since the test medium was prepared in tap-water purified by reverse osmosis (Milli-RO water, carbon levels < 500 ppb), IC was less than 5% of TC (mainly coming from the test substance, 14 mg TOC/L).

Results with reference substance:

- Functioning of the test system was checked by testing the reference substance sodium acetate, which showed a normal biodegradation curve. Biodegradation of sodium acetate at 14 days was 81%. The ThCO2 of sodium acetate was calculated to be 1.07 mg CO2/mg.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

Guanidine phosphate (1:1) was not readily biodegradable under the conditions of the modified Sturm test. Therefore, the target substance bisguanidinium phosphate is also considered to be not readily biodegradable.

Executive summary:

The readily biodegradation of guanidine phosphate (1:1) under the conditions of the carbon dioxide (CO2) evolution test (modified Sturm test) was investigated according to OECD guideline 301 B and GLP principles. A single test concentration of 14 mg TOC/L was tested during 28 days. Based on the obtained results, guanidine phosphate (1:1) was not readily biodegradable. The study is considered to be reliable without restrictions. Therefore, the target substance bisguanidinium phosphate is also considered to be not readily biodegradable.

Description of key information

Read Across: OECD 301B, GLP, CO2 evolution test, not readily biodegradable 

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

The readily biodegradation of guanidine phosphate under the conditions of the carbon dioxide (CO₂) evolution test (modified Sturm test) was investigated according to OECD guideline 301B and GLP principles. A single test concentration of 14 mg TOC/L was tested during 28 days. Based on the obtained results, guanidine phosphate was not readily biodegradable. The study is considered to be reliable without restrictions. Therefore, the target substance bisguanidinium phosphate is also considered to be not readily biodegradable.