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Environmental fate & pathways

Endpoint summary

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Additional information

Abiotic degradation:

Air: Based on estimation with the QSAR model Aopwin the substance undergoes in air rapid degradation after reaction with hydroxyl radicals or ozone. The DT50 values after reaction with hydroxyl radicals and ozone are 1.36 hours and 0.64 hours respectively. The substance will not reach the stratosphere and is therefore not considered to be a long-range transported chemical in air. The substance does not have an ozone depletion potential because it does not contain halogens and does not have the potential to reach the stratosphere (GHS, 3rd Edition, CLP, 2008).

Water: No experimental information is available on the hydrolysis of this substance. The substance is a terpinoid acetic-ester and it can be anticipated that the substance limitedly hydrolysis at pH4, somewhat at pH7 and significant hydrolysis is expected at pH9. For the risk assessment at pH 7 the half-life is estimated to be > 1 year based on information of somewhat similar fragrance type of acetates.

Biotic degradation:

In a biodegradation screening study (OECD Guideline 301F), after 28 days exposure of activated sludge to 100 mg/L of alpha-Terpinyl Acetate, 63% biodegradation was observed. Biodegradation starts on day 2 and reaches 58% at the end of the 10-day window. The substance is therefore characterised as being readily biodegradable. At the concentration tested, the substance is not inhibitory to micro-organisms.

Bioaccumulation:

Using the worst case assumption that alpha-Terpinyl Acetate will not metabolise in fish some bioaccumulation potential may be assumed based on calculated BCF values (based on an averaged log Kow of 4.4) for aquatic and terrestrial organisms of 1100 and 302 L/kg, respectively. However, it can be anticipated that simple esters, such as acetic esters, will be converted to the respective alcohols by carboxylesterases in fish liver and therefore the BCF values calculated are considered worst case values.

Transport and distribution:

The adsorption potential of alpha-Terpinyl Acetate was determined in a study according to OECD TG 121 (HPLC method) with Terpinyl Acetate multi, with which also alpha-Terpinyl Acetate was tested (see also toxico-kinetic section for similarity in constituents). Under the conditions of the test, the log Koc was determined at 2.79 (equivalent Koc = 620 L/kg). Based on this value it may be concluded that alpha-Terpinyl Acetate has moderate potential for adsorption to solid surfaces.

A Henry's law constant of 16 Pa·m³/mol (at 12 °C) was calculated in EUSES. Based on this value some partitioning from water to air may be expected.

Based on Level III environmental distribution modelling using EPISUITE (assuming equal and continuous releases to air, water and soil) using the CAS number 80 -26 -2 and the measured physico-chemical parameters (water solubility and log Kow) as input, it is estimated that the majority of the substance released to the environment will partition mainly into soil (83%) and water (16%) with small amounts to air (< 0.1%) and sediment (< 1%).

The SimpleTreat model, which is incorporated in EUSES, simulates the distribution of the substance in a Sewage Treatment Plant. Model calculations show that 79.5% of the substance will be degraded and that 10.8%, 5.4% and 4.3% will partition to water, sewage sludge and air, respectively.