Diammonium [[N,N'-ethylenebis[N-(carboxymethyl)glycinato]](4-)-N,N',O,O',ON,ON']cobaltate(2-)

Endpoint summary

Description of key information

Short-term toxicity on aquatic invertebrates

EC50 > 100 mg/l(based on nominal concentration)

Toxicity to aquatic algae and cyanobacteria

ErC50 > 400 mg/l (based on nominal concentration)

Additional information

Short-term toxicity on aquatic invertebrates

In the acute immobilization test with Daphnia magna (STRAUS), the effects of the test item were determined at the test facility according to OECD guideline 202.

The study was conducted under semi-static conditions over a period of 48 hours with the limit concentration of 100 mg/L of the test item.The test solution was shaken manually until the solution was visually clear. The limit concentration was colorless and visually clear throughout the exposure.

Twenty daphnids (divided into 4 replicates with 5 daphnids each) were exposed to the limit concentration and the control.

The concentration of Cobalt, component of the test item, was analytically verified via spectrophotometric analysis in the fresh media of the limit concentration and in the control at the start of the exposure and at the renewal of the test solutions (0 and 24 hours) and in the 24-hours old media at the renewal and at the end of the test (24 and 48 hours).

The measured concentration of Cobaltat the start of the exposure (0 and 24 hours) and at the end of the exposure (24 and 48 hours) was between of 5 and 6% of the nominal concentration. The geometric mean measured concentration of Cobalt was 0.754 mg/L.

Since the recoveries of the measured Cobalt concentration were not within ± 20% of the nominal concentration,the effect concentrations are based on geometric mean measured concentration of Cobalt. Additionally, the effect levels are given based on the nominal concentration of the test item.

The validity criteria of the test guidelines were fulfilled.

In the limit concentration 100 mg/L of the test item, which corresponds to the geometric mean measured concentration of 0.754 mg/L of the component Cobalt, no effects on Daphnia magna were observed.

Toxicity to aquatic algae and cyanobacteria

The toxicity of the test item to the unicellular freshwater green alga Pseudokirchneriella subcapitata was determined according to the principles of OECD guideline 201.

The aim of the study was the determination of the effects on growth rate and yield over a period of 72 hours. 

The study was conducted under static conditions with an initial cell density of 6442 cells/mL. A stock solution with a nominal loading of 400 mg test item/L was freshly prepared with dilution water. This dispersion was agitated until the solution was visually clear. The stock solution was diluted to obtain the required test item concentrations. Five concentrations were tested in a geometrical series with a spacing factor of 2.5: 10.2 - 25.6 - 64.0 - 160 - 400 mg/L, corresponding to the geometric mean measured cobalt concentration of 0.0171 – 0.0617 – 0.157 – 0.140 – 0.220 mg/L.

Three replicates were tested for each test item concentration and six replicates for the control. The environmental conditionswere within the acceptable limits.

The concentrations of the test item were analytically verified via spectrophotometric analysis at the start (0 hours) and at the end of the exposure (72 hours).

The measured concentrations of Cobaltat the start of the exposure (0 hours) were between 0 and 1% of the nominal concentration. At the end of the exposure (72 hours), the Cobalt concentration was detected in the range of 1 and 8 % of the nominal concentration

The EC₅₀-values for inhibition of growth rate (E_rC₅₀) and yield (E_yC₅₀) after 72 hours were > 400 mg/L [0.220 mg Co²⁺/L] and 235 (138 - 363) mg/L [0.190 (0.158 - > 0.220) mg Co²⁺/L], respectively. The NOEC for both growth rate and yield was 160 mg/L [0.140 mg Co²⁺/L].

Justification for classification or non-classification

According to the CLP Regulation (EC n. 1272/2008), Part 4: Environmental Hazards, the substances can be classified for hazardous to the aquatic environment (fish toxicity) when the following criteria are met:

A )Acute (short-term) aquatic hazard

Category Acute 1:

96 hr LC 50 (for fish) ≤ 1 mg/l and/or, 48 hr EC 50 (for crustacea) ≤ 1 mg/l and/or, 72 or 96 hr ErC 50 (for algae or other aquatic plants) ≤ 1 mg/l

B) Long-term aquatic hazard

(iii) Substances for which adequate chronic toxicity data are not available

Category Chronic 1:

96 hr LC 50 (for fish) ≤ 1 mg/l and/or 48 hr EC 50 (for crustacea) ≤ 1 mg/l and/or 72 or 96 hr ErC 50 (for algae or other aquatic plants) ≤ 1 mg/l

and the substance is not rapidly degradable and/or the experimentally determined BCF ≥ 500 (or, if absent, the log K ow ≥ 4).

Category Chronic 2:

96 hr LC 50 (for fish) > 1 to ≤10 mg/l and/or 48 hr EC 50 (for crustacea) > 1 to ≤10 mg/l and/or 72 or 96 hr ErC 50 (for algae or other aquatic plants) > 1 to ≤10 mg/l (Note 2)

and the substance is not rapidly degradable and/or the experimentally determined BCF ≥ 500 (or, if absent, the log K ow ≥ 4).

Category Chronic 3:

96 hr LC 50 (for fish) > 10 to ≤ 100 mg/l and/or 48 hr EC 50 (for crustacea) > 10 to ≤ 100 mg/l and/or 72 or 96 hr ErC 50 (for algae or other aquatic plants) > 10 to ≤ 100 mg/l

and the substance is not rapidly degradable and/or the experimentally determined BCF ≥ 500 (or, if absent, the log K ow ≥ 4).

Category Chronic 4

Cases when data do not allow classification under the above criteria but there are nevertheless some grounds for concern. This includes, for example, poorly soluble substances for which no acute toxicity is recorded at levels up to the water solubility (note 4), and which are not rapidly degradable in accordance with section 4.1.2.9.5 and have an experimentally determined BCF ≥ 500 (or, if absent, a log K ow ≥ 4), indicating a potential to bioaccumulate, which will be classified in this category unless other scientific evidence exists showing classification to be unnecessary. Such evidence includes chronic toxicity NOECs > water solubility or > 1 mg/l, or other evidence of rapid degradation in the environment than the ones provided by any of the methods listed in section 4.1.2.9.5.

The EC50 values calculated both for Daphnia and Alga studies are above the limit of classification; for this reason the substance under registration is not classified for aquatic toxicity according to CLP Regulation (EC) No. 1272/2008.