Diguanidinium carbonate

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

214 µg/L

Assessment factor:

10

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

306 µg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

21.4 µg/L

Assessment factor:

100

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

1.16 mg/L

Assessment factor:

100

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

1.2 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

insufficient hazard data available (further information necessary)

PNEC value:

0.12 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

114 µg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

The ecotoxicological Chemical Safety Assessment of Guanidine Carbonate bases on a full short- and long-term aquatic dataset, which indicates no relevant hazard to the aquatic environment or the microorganism communities in sewage water treatment plants. Due to the absence of high toxicity and persistence, the submission item falls into the low hazard soil toxicity class. Some literature data confirm the absence of effects to soil organisms up to high levels.

Therefore Guanidine Carbonate can be considered of low hazard for the environment.

Conclusion on classification

The text in COMMISSION REGULATION (EU) No 286/2011 of 10 March 2011 amending, for the purposes of its adaptation to technical and scientific progress, Regulation (EC) No 1272/2008 of the European Parliament and of the Council on classification, labelling and packaging of substances and mixtures, Official Journal of the European Union L 83/1-53, of 30.3.2011 replaces Part 4 of Annex I to Regulation (EC) No 1272/2008 is replaced and is thus used for classification.

Acute aquatic hazard

The acute aquatic hazard is according to table 4.1.0 a), page 21 relevant for classification if at least one of the three trophic levels shows a L(E)C50 of 1 mg/L or lower. The experimental L(E)C50 values were 65, 41 and >100 mg/L for algae, crustaceans and fish, respectively.

Thus no acute aquatic classification is required.

Long-term aquatic hazard

The submission item guanidine carbonate is not rapidly biodegradable as the modified OECD screening test of Kocsis (1998) revealed only 0.1 % degradation in 28 days. Thus table 4.1.0 b) i) applies.

As no long-term studies on crustaceans and fish are available for the submission item the classification bases on guanidine mononitrate (CAS 506-93-4) experiments. It is assumed and confirmed by QSPR (ChemAxon MarvinSketch version 5.3.6) that the protonated guanidine represents in the pH range from 0-10 more than 99 % of the guanidine species. Thus both guanidine mononitrate (source chemical) and guanidine carbonate (target chemical) are fully dissociated and aquatic organisms are exposed to the same chemical entities independent from the initially used salt. Solely the anions differ. As carbonate species are considered non-toxic, any read across from the nitrate to the carbonate on a molar guanidine basis seems justified. As the guanidine kation is univalent, the conversion factor equal to the mass ratio MW (CH5N3 + ½CH2O3) / MW (CH5N3 + HNO3), i.e. (59.071 + 62.025/2) / (59.071 + 63.013) = 90.0835 / 122.083, which gives ca. 0.74. Accordingly the classification is based on the chronic NOEC data of the nitrate of 181 mg/L ∙ 0.74 = ca. 134 mg/L for the fish, 2.9 mg/L ∙ 0.74 = ca. 2.14 mg/L for the daphnids and of the algal – NOEC of the carbonate, 4 mg/L. The lowest value is thus 2.14 mg/L, which is above the classifiable range. As all chronic NOEC were above 1 mg/L and the bioaccumulation potential based on the log Kow of ≤ -1.43 (Junghans 2009) or the BCF of the test surrogate guanidine (CAS 113-00-8) is low (< 0.1 to 0.1), no safety net classification is required.

Thus no long-term aquatic hazard classification is required.

Hazard to the ozone layer

Due to its chemical structural elements any ozone depleting potential of the submission item seems unlikely.