Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Constituents of OAPP show signs of environmental persistence, based on QSAR and experimental results. For further clarification, OAPP is subject of a substance evaluation process (CoRAP) (ECHA draft decision of 03 May 2019). Proposal: an enhanced ready-biodegradability test be carried out on a relevant dimer constituent, 1,1,3-trimethyl-3-phenylindan [CAS no. 3910-35-8] (Status 05 May 2019).

Additional information

Stability

Phototransformation in air

No data available (not required for REACH)

Hydrolysis

The substance Oligomerisation and alkylation reaction products of 2-phenylpropene and phenol (OAPP, phenol, methylstyrenated) contains constituents of the category phenols and phenyl substituted aliphatic compounds. These do not possess functional groups that are regarded as being susceptible to hydrolysis under environmental conditions. The test substance is considered to be not hydrolysable.

Phototransformation in water

No data available (not required for REACH)

Phototransformation in soil

No data available (not required for REACH)

 

Biodegradation

Biodegradation in water: screening tests

The substance oligomerisation and alkylation reaction products of 2-phenylpropene and phenol (OAPP, phenol, methylstyrenated) was not readily biodegradable under standard test conditions according to OECD TG 310 [CO2 in Sealed Vessels (Headspace Test)]. This finding is confirmed by a negative result on biodegradability of p-cumylphenol [CAS No. 599 -64 -4], a monostyrenated key component of the test substance, in a study according to OECD TG 301C.

Biodegradation in water and sediment: simulation tests

No data available

Biodegradation in soil

No data available.

Mode of degradation in actual use

No data available (not required for REACH)

 

Bioaccumulation

Bioaccumulation: aquatic / sediment: dietary exposure - OAPP = UVCB target compound

The bioaccumulation properties of the target substance OAPP have been investigated in a fish test (OECD 305, feeding variant). The study revealed that only the Dimers and Trimers of test material OAPP show a potential to be biomagnified. The lipid-corrected BMF values were 0.073 and 0.1374 for the dimers and trimers, respectively, both active ingredients of the test material. The growth-corrected half-lives were found to be 5.3 and 25.8 days, respectively. The corresponding BCF values, calculated on the basis of several approaches published in the literature are in the order of ≤ and ≥ 2000 for the dimers, and ≥ 5000 for the group of the trimers (further details in the ‘Bioaccumulation assessment’ document in the ‘Attached background material’ section). Uncertainty in these values are based on uncertainties in the conversion method employed.

 

Bioaccumulation: aquatic / sediment: aqueous exposure - constituents

No data is available on the target substance OAPP itself. p-Cumylphenol [CAS No. 599 -64 -4], a monostyrenated key component of the target substance, showed little bioaccumulating potential in fish, when, tested in a valid standard bioaccumulation study according to OECD 305 (via water-phase).

The BCF values ranged from 65 to 190 after 8 weeks of exposure.

For one non-phenolic key constituent, the dimer 1,1'-(1,1-dimethyl-3-methylene-1,3-propanediyl)bisbenzene (4-methyl-2,4-diphenylpent-1-ene) [CAS no. 6362-80-7], a reliable Japanese bioaccumulation study in fish (MITI-I protocol, according to OECD 305) is available (NITE 2002). Carps (Cyprinus carpio) were exposed for 60 days to two concentrations - 1 and 10 μg/L - with depuration for 16 days included. After normalisation to a lipid content of 5 %, the mean BCF values of two replicates were as follows (note: re-calculated to 5% lipid by the applicant):

High exposure: 2015 (day 42) / 3210 (day 60)

Low Exposure: 3890 (day 42) / 1750 (day 60).

The mean BCFs at steady state (day 28 to 60) are approx. 2320 L/kg (10 µg/L) and 2767 L/kg (1 µg/L). Based on these two values, bioaccumulation is assessed to be moderate rather than very high. The 60d value of <2000 at the low exposure level may indicate that the bioconcentration potential is low, but no firm conclusions can be drawn from the limited database.

Depuration following bioaccumulation

Elimination half-lives (as DT50) were given as 4.5 d (at the high exposure of 10 µg/L) and as 15.7 d for the low exposure (1 µg/L) (NITE 2002). A critical examination of the data evaluation in the report suggests that at least the comparatively long DT50 of 15.7 d is erroneous. A simple comparison of the initial tissue concentration (100%) with the residual one after 9 days suggest that the elimination half-lives are as follows (assuming first-order elimination kinetics):

High exposure (10 µg/L): decrease ~95%/9d = ~4 T/2 --> DT50 = ~2.3d

Low exposure (1 µg/L): decrease ~83%/9d = ~2.7 T/2 --> DT50 = ~3.3d.

These findings are consistent with low to moderate bioaccumulation potential for the non-phenolic dimers of oligomerisation and alkylation reaction products of 2-phenylpropene and phenol.

 

Bioaccumulation: terrestrial

No data available (not required for REACH)

 

Transport and distribution

Adsorption/Desorption

The substance oligomerisation and alkylation reaction products of 2-phenylpropene and phenol (previous name phenol, methylstyrenated) contains components with high log Pows ranging from 3.6 to ≤ 6.3. Corresponding adsorption constants (organic matter - water), log Koc, calculated from the log Pow are expected to range from 3.24 - 5.90 (based on Karickhoff 1981: log Koc = 0.989 x log Pow - 0.346). Moreover, water solubility is low (1 - 7 mg C/L at a loading of 100 mg/L). These properties indicate high adsorption and low mobility in soil.

Based on a log Pow of 6.3 (see Chapter 1.3), a log Koc of 5.88 (Koc = 760,000) is calculated for the substance using the relation of Karickhoff.

The Henry's law constant was estimated to be 3.278 Pa*m³/mol using the vapour pressure (0.044 Pa), the water solubility (4 mg/L), and the average molecular weight (298 g/mol) of the substance (see Chapter 1.1 and 1.3).