6,6-dimethylbicyclo[3.1.1]hept-2-ene-2-propionaldehyde

Toxicity to soil macroorganisms except arthropods

Description of key information

For Pino Acetald, the EC10 was determined to be 97.8 mg/kg dw, based on read across from Pinyl isobutyr aldehyde.

Key value for chemical safety assessment

Long-term EC10, LC10 or NOEC for soil macroorganisms:

97.8 mg/kg soil dw

Additional information

For Pino Acetald no experimental data on toxicity to soil macroorganisms is available, this information can be retrieved from Pinyl isobutyr aldehyde using read across. First the experimental information of Pinyl isobutyr aldehyde is presented and thereafter the read across justification to use this information for Pino Acetald.

Pinyl isobutyr aldehyde

Pinyl Isobutyraldehyde is tested for its effects on Reproduction and Growth of Earthworms Eisenia andrei in Artificial Soil according to OECD TG 222. Adult worms were exposed to a control and the concentrations 3.2, 10, 40, 120 and 380 mg/kg dw soil for 56 days. Four replicates were used for the test concentrations and 8 for the control. Every replicate contained 10 earthworms. Mortality, behavioural effects, such as feeding activity and biomass development was assessed after 28 days exposure in treated artificial soil. Reproduction rate (number of offspring) was assessed after additional 28 days (assessed 56 days after application). At experimental start no behavioural abnormalities were observed up to the concentration of 40 mg test item/kg soil. The feeding activity was comparable to the control up to and including the test concentration of 120 mg test item/kg dw soil and was reduced at 380 mg test item/kg soil. At 120 mg test item/kg dw soil in two replicates one earthworm did not burrow into the soil and at 380 mg test item/kg dw soil several earthworms were laying on the surface approximately 0.5 to 1 hour after introduction. No mortality was observed up to and including the test concentration of 40 mg test item/kg soil. The mortality of 7.5% at 120 mg test item/kg was not statistically significantly different compared to the control. At 380 mg test item/kg soil all worms were dead after 28 days, the LC50 is therefore between 120 and 380 mg/kg dw soil. The body weight changes of the earthworms after 4 weeks exposure to Pinyl Isobutyraldehyde were not statistically significantly different compared to the control up to and including the test concentration of 40 mg test item/kg dw soil. At 120 mg test item/kg soil the weight increases were statistically significantly lower compared to the control. The reproduction rates were not statistically significantly different compared to the control up to and including the test concentration of 40 mg test item/kg soil. At 120 mg test item/kg dw soil and above reproduction was statistically significantly reduced compared to the control. In this earthworm reproduction and growth study with Pinyl Isobutyraldehyde the LC50 was determined to be 156.7 mg test item/kg dw soil. The EC10 was determined to be 97.8 mg test item/kg dw soil (95% confidence limits of 93.1 to 102.7 mg test item/kg dw soil) and the NOEC was determined to be 40 mg test item/kg dw soil.

Pino Acetald (Cas no.: 33885-51-7) and its toxicity to earthworms using read across from Pinyl Isobutyr aldehyde (CAS no.: 33885-52-8)

Introduction and hypothesis for the analogue approach

Pino Acetald is an alpha-Pinene with a propanal chain attached to the methyl group present at the second position. For this substance, no data on toxicity to soil macro-organisms is available. In accordance with Article 13 of REACH, lacking information can be generated by means of applying alternative methods such as in vitro tests, QSARs, grouping and read-across. For assessing the toxicity to soil macro-organisms of Pino Acetald, the analogue approach is selected because for a related analogue, reliable toxicity data are present, which can be used for read-across.

Hypothesis: Pino Acetald has similar toxicity to soil macro-organisms compared to Pinyl Isobutyr aldehyde.

Available experimental information: For Pinyl Isobutyr aldehyde long-term terrestrial toxicity information is available for earthworms performed according to OECD TG 222 following GLP receiving a Klimisch score of 1. In addition, for both substances an algae and acute daphnia toxicity test are available all receiving Klimisch 1.

Target chemical and source chemical(s)

Chemical structures of the target chemical and the source chemicals and relevant information on these substances are shown in the data matrix.

Purity / Impurities

Pino Acetald is a mono-constituent with a purity of 98.4% and all impurities are < 2%.

Analogue approach justification

According to Annex XI 1.5 read across can be used to replace testing when the similarity can be based on a common backbone and a common functional group. When using read across the result derived should be applicable for C&L and/or risk assessment and it should be presented with adequate and reliable documentation, which is presented below.

Analogue selection: For Pino Acetald the structural close analogue Pinyl Isobutyr aldehyde is selected for read across because for this substance experimental information on soil macro-organism toxicity is available.

Structural similarities and differences: Pino Acetald and Pinyl Isobutyr aldehyde have the same backbone and functional groups. They are both alpha-Pinenes with a propanal chain attached. The difference is the addition of two methyl groups to the propanal chain of Pinyl Isobutyr aldehyde. These two additional -CH3 fragment increases the log Kow with 1.0 using KowWIN for prediction.

Bioavailability: Pino Acetald and Pinyl Isobutyr aldehyde have similar bioavailability based on the similarity in chemical structure and physico-chemical properties as presented in the data matrix and based on measured and calculated data (Table 1).

Mode of Action (MoA): Both Pino Acetald and Pinyl Isobutyr aldehyde have an acetal MoA according to ECOSAR and OECD Toolbox.

Conversion: Pino Acetald toxicity to soil macro-organisms can be predicted from Pinyl Isobutyr aldehyde A conversion was not needed because the molecular weight conversion balanced the log Kow conversion (179 versus 206 molecular weight and 4.3 versus 5.4 log Kow for Pino Acetald and Pinyl Isobutyr Aldehyde, respectively).

Uncertainty of the prediction: There are no other uncertainties than those which have been addressed above.

Data matrix

The relevant information on physico-chemical properties and toxicological characteristics are presented in the data matrix below.

Conclusions for aquatic toxicity

For Pino Acetald no experimental toxicity to soil macro-organism test is available, but for the structural analogue Pinyl Isobutyr aldehyde such information is present. When using read across the result derived should be applicable for C&L and/or risk assessment and be presented with adequate and reliable documentation. This documentation is presented in the current document. Pinyl Isobutyr aldehyde has a 56d-EC10 value of 97.8 mg/kg soil dw. As conversion was not needed because the molecular weight conversion balanced the log Kow conversion, the 56d-EC10 of Pino Acetald is 97.8 mg/kg soil dw.

Final conclusion on hazard: For Pino Acetald toxicity to soil macro-organisms is based on the structural analogue Pinyl Isobutyr aldehyde. This results in a 56d-EC10 of 97.8 mg/kg soil dw.

Data matrix: Information on Pino Acetald and Pinyl Isobutyr aldehyde for assessment of toxicity to soil macro-organisms.

Common names	Pino Acetald Target	Pinyl Isobutyr aldehyde Source
Chemical structures
Chemical name	6,6-dimethylbicyclo[3.1.1]hept-2-ene-2-propionaldehyde	α,α,6,6-tetramethylbicyclo[3.1.1]hept-2-ene-2-propionaldehyde
CAS no.	33885-51-7	33885-52-8
EC no.	251-717-2	251-718-8
Empirical formula	C12H18O	C14H22O
Molecular weight	178.75	206
Phys-Chem
Physical state	Liquid	Liquid
Water solubility (mg/L)	61 at 24°C (OECD 105)	10.8 at 22°C (OECD 105)
Log Kow	4.3 (OECD TG 117)	5.4 (OECD TG 117)
Aquatic toxicity
Algae (72h-ErC50) (mg/l)	4.2 (OECD 201)	>0.66 (OECD 201)
Algae (72h-ErC10) (mg/l)	1.9 (OECD 201)	0.37 (OECD 201)
Daphnia (48h-EC50) (mg/l)	0.67 (OECD 202)	0.51 (OECD 202)
Earthworms (56-EC10) (mg/kg soil dw)	Read across	97.8 (OECD 222)