Eucalyptus globulus, ext.

Toxicity to aquatic algae and cyanobacteria

Description of key information

Constituent approach, additivity formula:
EC50 for algae = 0.88 mg/L for Eucalyptus oil.
NOEC for algae = 1.64 mg/L for Eucalyptus oil.

Key value for chemical safety assessment

EC50 for freshwater algae:

1.64 mg/L

EC10 or NOEC for freshwater algae:

0.88 mg/L

Additional information

Based on a weight of evidence approach, the toxicity of Eucalyptus oil to algae can be estimated using adequate toxicity data of major constituents, greater than 10% in the mixture. Three constituents were considered, representing 90% of the mixture. To obtain worst case estimations, the worst case percentages of each constituent were taken into account based on the individual toxicities of these compounds. These data are summarized in the table below:

Constituents	Worst-case composition	Algae ErC50, mg/L	Algae NOECr, mg/L	Reference in IUCLID 6
Cineol 1,8	55%	> 74	37	1,8-Cineol, 470-82-6, Toxicity to aquatic algae and cyanobacteria, Vryenhoef, 2013, RS, W
Limonene	12%	> 1.6	1.6	(d,l)-limonene, 138-86-3, Toxicity to aquatic algae and cyanobacteria, MITI, 1998, RS, W
Pinene α	23%	> 0.494	0.247	alpha-pinene, 7785-26-4, Toxicity to aquatic algae and cyanobacteria, Delpit, 2013, RS, W

The acute and chronic toxicity of Eucalyptus oil to algae were estimated using the following additivity formulas, as recommended in the Regulation (EC) No 1272/2008 (CLP):

∑ Ci / L(E)C50m = ∑ (Ci / L(E)C50i)

Where,

Ci = concentration of component i (weight percentage);

L(E)C50i = LC50 or EC50 for component i, in mg/L;

L(E)C50m = L(E)C50 of the part of the mixture with test data.

(∑ Ci + ∑ Cj) / EqNOECm = ∑ (Ci / NOECi) + ∑ (Cj / 0.1 x NOECj)

Where,

Ci = concentration of component i (weight percentage) covering the rapidly degradable components*;

Cj = concentration of component j (weight percentage) covering the non-rapidly degradable components;

NOECi = NOEC for component i covering the rapidly degradable component, in mg/L;

NOECj = NOEC for component j covering the non-rapidly degradable components;

EqNOECm = Equivalent NOEC of the part of the mixture with test data.

* All major constituents of Eucalyptus oil are considered readily biodegradable.

 

Based on data presented above, the EC50m and EqNOECm values for Eucalyptus oil were estimated to be 1.64 mg/L and 0.88 mg/L for algae (based on growth rate) for a worst case typical mixture, respectively. The worst case assumption is validated by comparable calculations performed with fishes and validated with 2 studies.