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Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

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

Adequacy of study:

key study

Study period:

14 March 2016 to 18 March 2016

Reliability:

1 (reliable without restriction)

Justification for type of information:

The analogue approach is used for the hazard assessment of toxicological, eco-toxicological and environmental fate endpoints for the registration Pentamid™ KH (EC 934-047-1). The hypothesis is that data can be read-across between Pentamid™ KH and its structural analogues, based on structural similarity and common breakdown/metabolic products (Scenario 1 of the Read-Across Assessment Framework (RAAF, ECHA, 2015)).

The substance and its analogue have not been shown to exhibit toxicity to aquatic organisms (based on short-term studies on all three trophic levels) or be inhibitory to degradative micro-organisms. While neither the substance nor its analogue have been shown to be readily biodegradable, both exhibit inherent primary degradability and are not expected to be highly persistent in the environment. The low solubility, high octanol-water partition coefficient and non-rapid degradation in the environment, attributable to both the substance and its analogue, suggest that long-term exposures may be of potential concern.

The sole classification for Pentamid™ KH is the precautionary aquatic chronic 4 category, based on low water solubility and a log Kow higher than 4.

Read-across data, all evaluated as reliable according to Klimisch scores of 1 or 2, to estimate the toxicity of the registered substance is used for fulfilling the data requirements of the REACH registration and classifying potential hazards. This read-across approach is adequate for the purposes of risk assessment and classification and labeling.

Reason / purpose for cross-reference:

read-across source

GLP compliance:

yes (incl. QA statement)

Key result

Duration:

72 h

Dose descriptor:

EL50

Remarks:

Based on WAF

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOELR

Remarks:

Based on WAF

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EL50

Remarks:

based on WAF

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

< 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Conclusions:

Inhibtion of growth rates of the freshwater green alga Pseudokirchneriella subcapitata after 72 hours based on the Water Accommodated Fraction (WAF) nominal loading of the test item, HOSTAGEL HT 300, was not reported. The EL50 values for both inhibition of growth rate (ErL50) and yield (EyL50) after 72 hours were > 100 mg/L. The NOEL-values for inhibition of growth rate and yield after 72 hours were 100 mg/L and < 100 mg/L, respectively.

Description of key information

The key study was a static acute toxicity test on the effects of the substance, HOSTAGEL HT 300, on the freshwater unicellular green alga, Pseudokirchneriella subcapitata following OECD Guideline 201. The test substance did not inhibit growth of the freshwater green alga Pseudokirchneriella subcapitata after 72 hours based on the Water Accommodated Fraction (WAF) nominal loading of the test item. The EL₅₀ values for both inhibition of growth rate (ErL₅₀) and yield (EyL₅₀) after 72 hours were > 100 mg/L. The NOEL values for inhibition of growth rate and yield after 72 hours were 100 mg/L and < 100 mg/L, respectively.

 

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

100 mg/L