(S)-p-mentha-1,8-diene

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

5.4 µg/L

Assessment factor:

50

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

3.6 µg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.54 µg/L

Assessment factor:

500

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

0.2 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

1.322 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.132 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:

0.262 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

PNEC oral

PNEC value:

133 mg/kg food

Assessment factor:

30

Additional information

PNECs aqua

Several reliable studies were conducted on algae, daphnia and fish with d-limonene, the enantiomer of l-limonene and with dipentene, the racemic form (dl) of limonene. Toxicity results were similar for d-limonene and dipentene suggesting that both enantiomer have the same level of toxicity on these aquatic organisms. This hypothesis is reinforced by the estimations of the toxicity of l-limonene by a valid QSAR model (ECOSAR) which are similar to the result with d-limonene and dipentene except for algae when the result is lower especially for chronic toxicity.

From these results, it can be concluded that the toxicity of the two enantiomers, d and l limonene, regarding daphnids and fish is similar and that d-limonene and dipentene can be used as analogue of l-limonene in a read-across approach to fill data gaps. Among these studies, the geometric mean 96h-LC50 of 0,71 mg/L for fish, the lowest 48h-EC50 of 0,36 mg/L and the 21d-NOEC= 0.27 mg/L for daphnia are considered as the relevant values to be used for the purpose of risk assessment and classification and labelling. Nevertheless, for algae the lower estimated values, 72h-ErC and 72h-NOErC of 0.904 and 0.514 mg/L,for l-limonene with ECOSAR is prefered as more conservative values because detailed information on the purity of d-limonene and dipentene in the available tests is missing.

 

PNEC stp

One reliable ready biodegradability study on l-limonene and one reliable activated sludge respiration test (ASRIT) on dipentene (48.4% dl-limonene) were available to assess the toxicity of l-limonene to microorganisms. The result of the ASRIT on dipentene is difficult to interpret the specific toxicity of l-limonene (multi-constituents substance) however the test conclude that the test item was not harmful to activated sludge. According to ECHA, Chapter R. 7b, Endpoint specific guidance (2008), the information content of the ready biodegradability test can be used to derive a NOEC. In the case of l-limonene, the ready biodegrability test in close bottles fulfilled the requested conditions as described below :

- the compound is found to be readily biodegradable,

- test substance concentration (2 mg/L) was not above the solubility limit of l-limonene (12.3 mg/L).

- a toxicity control hasn't been included in the test but no inhibition of the endogenous respiration of the inoculum by l-limonene was detected.

Therefore, a NOEC of 2 mg/L corresponding to a good degradated tested concentration was estimated from the biodegradation test and used to derive the PNECstp.

PNEC sediment and soil

 In the absence of any ecotoxicological data for sediment-dwelling organisms and terrestrial organisms, the PNECsed and the PNECsoil were calculated using the equilibrium partitioning method (EPM).

 

PNEC oral

A 6-month subchronic repeated dose toxicity study was performed similarly to OECD Guideline 409 with d-limonene administered through gavage to groups of adult beagle dogs (IUCLID endpoint 7.5.1, RA, 5989-27-5, Repeated dose toxicity: oral 180-d dog, Webb, 1990, RS, K).

Under the test conditions, the NOAEL and LOAEL for beagle dogs were considered to be 100 and 1000 mg/kg bw/day, respectively, based on the increased absolute and relative female kidney weight and relative male kidney weight.

A NOEC mammals-food-chr of 4 g/ kg food is derived from the NOAEL and a PNEC oral of 133 mg/kg food is calculated according to the ECHA guidance on information requirments and chemical safety assessment Chapter 10 using a convertion factor of 40 and an assessment factor of 30, respectively.

 

Conclusion on classification

The selected data on acute and chronic toxicity on aquatic organism issued from read-across with d-limonene and dipentene or calculated value with a valid QSAR, and relevant for classification of l-limonene are:

Acute toxicity

48h-EC50 for daphnia: 0.36 mg/L

96h-LC50 for fish: 0.72 mg/L

72h-ECr50 for algae: 0.904 mg/l

Chronic toxicity

21d-NOEC for daphnia: 0.27 mg/L

72h-NOErC for algae: 0.514 mg/L

The substance l-limonene is readily biodegradable.

The Log Kow of d-limonene was measured at 4.38 and is expected to be similar for both enantiomers. There was no experimentaly determined BCF however the retained QSAR value is 683 L/kg ww and therefore l-limonene cannot be considered not having potential to bioaccumulate.

Based on these information l-limonene should be classified:

Acute Category 1 (M-factor = 1) and Chronic Category 3 according to the CLP Regulation (EC) nº 1272/2008.