Sodium D-glycero-D-gulo-heptonate

Toxicity to aquatic algae and cyanobacteria

Description of key information

An algal growth study was conducted on a close structural analogue (Sodium Glucoheptonate), this study was conducted according to OECD guideline 201 and EU Method C3. The results of this study showed Sodium Glucoheptonate to have an 96 hour EC50 value of 790 mg/L and a 96 hour NOEC of 100 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

790 mg/L

EC10 or NOEC for freshwater algae:

100 mg/L

Additional information

Read-across discussion:

In order to address ecotoxicological endpoints as part of the REACH registration of Sodium d-glycero-d-gulo-heptonate (target substance) it is proposed to read across data from Sodium glucoheptonate (source substance). The use of read across is within the spirit of REACH, in order to reduce animal testing where possible.

The source and target substances are structurally similar consisting of the alpha/ beta and alpha only form of the same isomer (respectively) and have the same molecular weight, the substances also have comparable physical chemical properties. Due to the similar properties shown between the two materials it is believed that the results obtained in the testing of sodium glucoheptonate (source substance) will be a reliable representation of the properties for sodium d-glycero-d-gulo-heptonate (target substance) to allow classification and labelling and for risk assessment purposes. Therefore read across is justified. The substance sodium d-glycero-d-gulo-heptonate is considered to have similar properties to sodium glucoheptonate and therefore is considered to be relatively harmless and would not be classified in accordance with Regulation (EC) No 1272/2008 (CLP).

Study discussion:

Introduction:

A study was performed to assess the effect of the test item on the growth of the green alga Pseudokirchneriella subcapitata. The method followed that described in the OECD Guidelines for Testing of Chemicals (2006) No 201, "Freshwater Alga and Cyanobacteria, Growth Inhibition Test" referenced as Method C.3 of Commission Regulation (EC) No 761/2009 and the US EPA Draft Ecological Effects Test Guideline OPPTS 850.5400. Please note this study was actually conducted on a close structural analogue (Sodium Glucoheptonate), this is why the study has been assigned a klimisch reliability of 2.

 

Methods:

Following a preliminary range-finding test, Pseudokirchneriella subcapitata was exposed to an aqueous solution of the test item at concentrations of 10, 32, 100, 320 and 1000 mg active ingredient (ai)/L (three replicate flasks per concentration) for 96 hours, under constant illumination and shaking at a temperature of 24 ± 1 °C.

 

Samples of the algal populations were removed daily and cell concentrations determined for each control and treatment group, using a Coulter^®Multisizer Particle Counter.

Results:

Exposure of Pseudokirchneriella subcapitata to the test item gave the following results:

 

Time Point (Hours)	Response Variable	EC50(mg ai/L)	95% Confidence Limits (mg ai/L)			No Observed Effect Concentration (NOEC) (mg ai/L)	Lowest Observed Effect Concentration (LOEC) (mg ai/L)
72	Growth Rate	510		*		32	100
	Yield	150	120	-	190	32	100
	Biomass	160	140	-	190	32	100
96	Growth Rate	790		*		100	320
	Yield	220	180	-	260	10	32
	Biomass	180	140	-	210	32	100

Analysis of the test preparations at 0 and 96 hours showed measured test concentrations to range from 93% to 105% of nominal and therefore the results are based on nominal test concentrations only, as this coincides within the acceptable range of between 80 and 120%.

A re-growth test was performed which showed the test item to be algistatic in effect.