By-product from Guanidinoacetic acid manufacturing

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2020-07-16 - 2021-04-26

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

200116MA1 liquid

Analytical monitoring:

yes

Details on sampling:

concentrations and the control were taken at the start of the test and at day 1.
For the determination of the stability of the test item under the test conditions and of the maintenance of the test item concentrations during the test period, four samples from the aged test media of all test concentrations and the control were collected at day 1 (after 24 hours of exposure) and at the end of the test by pouring together the contents of the test beakers of each treatment.
One set of duplicate samples of each sampling point was used for the analysis of DCD and Hydantoic acid.
The other set of duplicate samples of each sampling point was used for the determination of total organic carbon (TOC).
All samples remained undiluted.

Vehicle:

no

Test organisms (species):

Daphnia magna

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

2.5 mmol/L (= 250 mg/L) as CaCO3

Test temperature:

20.1 to 20.8 °C in the freshly prepared media;
20.2 to 20.8°C in the aged test media

pH:

7.7 to 8.0 in the freshly prepared media;
7.9 in the aged test media; and thus the pH-value did not vary by more than 1.5 units

Dissolved oxygen:

8.7 to 9.1 mg/L in the freshly prepared media;
7.9 to 8.7 mg/L in the aged test media

Nominal and measured concentrations:

Nomnal concentrations:
889, 404, 184, 83.5 and 37.9 mg test item/L
equivalent to 160, 72.7, 33.1, 15.0 and 6.83 mg total dissolved solids/L
equivalent to 24.003, 10.908, 4.968, 2.255, 1.023 mg DCD/L

Measured concentrations (% of nominal):

24.003 mg/L: 105
10.908 mg/L: 99
4.968 mg/L: 97
2.255 mg/L: 101
1.023 mg/L: 100

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

> 160 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

mg dissolved solids/L

Basis for effect:

mortality

Validity criteria fulfilled:

yes

Conclusions:

The toxic effect of the test item "Solution of By-product from Guanidinoacetic acid manufacturing" to Daphnia magna was assessed in a semi-static concentration-response test. The 48-hour NOEC was determined to be ≥ 889 mg test item/L / ≥ 160 mg dissolved solids/L (based on immobility). The 48-hour LOEC was determined to be > 889 mg test item/L / > 160 mg dissolved solids/L (based on immobility) and the 48-hour EC50 value was determined to be > 889 mg test item/L / > 160 mg dissolved solids/L.

Executive summary:

The toxic effect of the test item "Solution of By-product from Guanidinoacetic acid manufacturing" to Daphnia magna was assessed in a semi-static concentration-response test. The 48-hour NOEC was determined to be ≥ 889 mg test item/L / ≥ 160 mg dissolved solids/L (based on immobility). The 48-hour LOEC was determined to be > 889 mg test item/L / > 160 mg dissolved solids/L (based on immobility) and the 48-hour EC50 value was determined to be > 889 mg test item/L / > 160 mg dissolved solids/L.
The initial concentrations and the maintenance of the exposure concentrations during the test were determined in the analytical part.
Correct dosage was confirmed by the analysis of the component DCD of the test item because DCD is the component with the highest content in the test item. This component is stable under the experimental conditions and does not undergo any reaction with any other component of the test item. Furthermore, a reference substance is commercially available.
All reported results refer to nominal values since the concentrations of DCD in the test item were within ± 20% of the nominal concentrations during the test and “Solution of By-product from Guanidinoacetic acid manufacturing” is an UVCB substance (Unknown or Variable composition, Complex reaction products or Biological material).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Remarks:

mg dissolved solids / mL

Effect concentration:

> 160 mg/L