(E)-3-methyl-5-cyclopentadecen-1-one

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

2.42 µg/L

Assessment factor:

50

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

2.2 µg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.242 µg/L

Assessment factor:

500

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

10 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

3.66 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.37 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:

2.34 mg/kg soil dw

Assessment factor:

50

Extrapolation method:

assessment factor

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

PNEC oral

PNEC value:

111.1 mg/kg food

Assessment factor:

90

Additional information

Read-across justification:

The read-across substance (used for the long-term toxicity to aquatic invertebrates) is considered adequate for read-across purposes (see IUCLID section 13 for justification).

Aquatic toxicity:

Acute and chronic data are available for the three trophic levels: Algae, Invertebrates and Fish.

Among all species tested, toxic effects were found for aquatic invertebrates and fish.

- For the aquatic invertebrates Daphnia magna, the acute toxicity of the registered substance was assessed for 48 hours under static test conditions. The 48h-EC50 was 0.39 mg/L. For the chronic toxicity, a read-across approach was used under semi-static test conditions with a read-across substance as the study performed on the registered substance is considered invalid. This read-across substance is considered adequate for read-across purposes (see IUCLID section 13 for justification). Indeed, this substance is one of the constituents of the registered substance, together with isomers. The read-across substance is a mono-constituent, individual optical isomer, while the registered substance is defined as a multi-constituent, with three pairs of racemate. The 21d-EC10 (Daphnia magna) was determined at 0.121 mg/L based on intrinsic rate of population increase. This result is in accordance with the expected result on the registered substance.

- For the fish, the acute toxicity of the registered substance to Oncorhynchus mykiss was assessed for a period of 96 hours under semi-static conditions. The 96h-LC50 was 0.22 mg/L. For the chronic toxicity, a study was performed to assess the effects of the registered substance on freshly hatched larvae of the fathead minnow Pimephales promelas, for a period of 10 days under flow-through conditions. This was a compromise and a decision based on the technical challenges to maintain constant concentrations of the test substance in solution. Those Dosing Trials and Range Finding tests lasted 10 months and led to the conclusion that three concentrations could be maintained over a short period of time.  A special test design was constructed in order to dose the test substance (concentration generators and metallic splitters) that was implemented in the laboratory.  The 10d-EC10 was 0.18 mg/L based on survival. Given the inadequacies of the previous invalid fish ELS study (2003), conducted on the registered substance, it is considered that the above result provides a more reliable assessment of the chronic effects of the registered substance on the early life stages of fish.Indeed, even if the study period is shorter (10 days) than a real chronic study, the substance was well maintained at stable aqueous concentrations during the test and therefore the study provide a more reliable exposure system. In addition, as the substance has a non-specific narcotic mode of action, smaller differences in sensitivity between this study and the full early-life stage test (OECD Guideline 210) is expected, as mentionned in the OECD Guideline 212 (1998).

- For the algae Scenedesmus subspicatus, the effect of the registered substance on the growth of the green alga was assessed for 72h. Exposure of algae to the substance gave EC50 and NOEC values greater than the highest attainable test concentration of 30 mg/L. The test concentration of 30 mg/L was the highest attainable test concentration that could be prepared due to the limited solubility of the test material in water (corresponding to 0.69 mg/L in aquatic medium) and auxiliary solvent and having due regard to the amount of auxiliary solvent permitted in the test under the OECD guidelines.

- For the microorganisms and in accordance with column 2 of REACH Annex VIII, the activated sludge respiration inhibition test does not need to be conducted because the substance is readily biodegradable and the applied test concentrations are in the range of concentrations that can be expected in the influent of a sewage treatment plant.

Terrestrial toxicity:

Three key studies are available to determine the terrestrial toxicity of the registered substance.

- The first study was performed to assess the acute toxicity of the registered substance to the earthworm (Eisenia fetida) in an artificial soil, according to OECD Guideline 207 and EEC Commission Directive 87/302/EEC. The 14d-LC50 value based on the mortalities of earthworms was determined to be 250 mg/Kg (95% confidence limits = 240 -260 mg/Kg).

- The second study was performed to assess the effects of the registered substance on seedling emergence and growth on three different species: oat (Avena sativa), soybean (Glycine max) and tomato (Lycopersicon esculentum), according to OECD Guideline 208 part A. This original guideline is considered as an acute test, when only three plant species are used in the test (http://echa.europa.eu/documents/10162/13628/evaluation_report_2012_en.pdf see pp 34-35). The 25d-EC50 to oat, the 26d-EC50 to soybean and the 28d-EC50 to tomato, based on percent emergence and shoot weight, were determined to be greater than the maximum rate tested 1100 mg/Kg. The highest concentration without observed effect (NOEC) were determined to be 117 mg/Kg for shoot weight of oat and 1100 mg/Kg for percent emergence and shoot weight of soybean and tomato. Necrosis in solvent controls and a poor dose-effect relationship for shoot weights were observed for oat and tomato. Therefore, the results with these two species must be taken into account with caution.

- The third study was performed to assess the long-term effect of the registered substance after a single exposure, on nitrogen transformation activity of soil microorganisms, according to OECD guidelines 216 and EPPO 1994. The substance showed no significant effect on the nitrogen transformation activity of soil microorganisms at a test concentration of 1000 mg/Kg over a 28 -day period (NOEC >= 1000 mg/Kg) and therefore can be considered to have no long-term effect on nitrogen transformation in soil.

Even if the plant study available is considered as an acute test (based on number of tested species), the NOEC value is the lowest, so it’s justified to use it for PNEC derivation. As a long-term toxicity test on microorganisms is available (OECD 216; NOEC >= 1000 mg/kg on soil microorganisms) showing a NOEC value greater than the NOEC plant, an assessment factor of 50 is used. Therefore, the PNEC soil is equal to 117/50 = 2.34 mg/kg dw.

Environmental fate and pathways:

Based on the key biodegradation studies, the registered substance is considered readily biodegradable (Wildlife International, 2000) and is considered almost totally removed from a WasteWater Treatment Plants (WWTP) (99.9% of removal; Weston, 1995). As the substance is readily biodegradable, no further assessment of the stability of this compound is necessary (e.g. hydrolysis study).

The adsorption coefficient (Koc) of the registered substance was estimated with three calculation methodologies using the experimental log Kow value of 5.52: MCI method from KocWin v2.00 (EPI Suite v4.1), log Kow method from KocWin v2.00 (EPI Suite v4.1) and TGD equation. The retained value is a geometric mean of these results, corresponding to a log Koc at4.18 (Koc = 15094 L/kg).This result indicates that the substance is immobile in soil (according to P.J. McCall et al., 1980).

Conclusion on classification

The harmonised classification of the substance is Aquatic Acute 1 and Aquatic Chronic 1 according to Annex VI of Regulation (EC) No 1272/2008 (CLP Regulation, ATP01).

This harmonised classification is not in agreement with the data presented in the dossier as the substance is Aquatic Acute 1 (M-factor = 1) but should be reclassified Aquatic Chronic 3 instead of Aquatic Chronic 1 based on new data.

The lowest chronic EC10 value is comprised between 0.1 and 1 mg/L (21d-EC10 = 0.121 mg/L, Daphnia magna) and the substance is readily biodegradable.