Naphtha (petroleum), steam-cracked, C8-10 aromatic hydrocarbon fraction, alkylated and oligomerised

Endpoint summary

Additional information

Stability

Phototransformation in air

Based on calculations with the programme US EPA EPI Suite, the half-life of the substance 'Naphtha (petroleum), steam-cracked, C8-10 aromatic hydrocarbon fraction, alkylated and oligomerised' (NAF-AO) [EC no. 615 -276 -3] (see Chap.1) in air (transformation by reaction with OH radicals) is short (< 1 day).

Hydrolysis

The substance NAF-AO does not contain constituents that possess functional groups that are susceptible to hydrolysis. The 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 NAF-AO was not biodegradable under standard test conditions according to OECD TG 310 [CO2 in Sealed Vessels (Headspace Test)] (Clarke/Harlan 2010). This finding seems to be confirmed by a Japanese study (MITI-I test, corresponding to OECD 301C) on 2,4-diphenyl-4-methyl-1-pentene [CAS no. 6362-80-7] (EC name 1,1'-(1,1-dimethyl-3-methylene-1,3-propanediyl)bisbenzene), a dimeric constituent of NAF-AO, which forms part of the low-molecular fraction of the substance. Under the test conditions after 28 d, the dimer showed no degradation measured by oxygen consumption and 7 % degradation measured by HPLC analysis. In conclusion, the test substance was not readily biodegradable (MOE/NITE 2002).

However, an external study according to OECD 302C (inherent biodegradability) gave clear evidence of inherent biodegradability of this dimer (report not available, not included in IUCLID).

The biodegradability of components of NAF-AO is intended to be further tested in the context of a test programme for another substance (Oligomerisation and alkylation reaction products of 2 -phenyl-propene and phenol, EC no. 700-960-7) that has prominent constituents in common with NAF-AO.

Biodegradation in water and sediment: simulation tests

No data available (data waiving)

Biodegradation in soil

No data available (data waiving)

Mode of degradation in actual use

No data available (not required for REACH)

 

Bioaccumulation and depuration

General

No bioaccumulation data are available on NAF-AO itself. The evaluation of its bioaccumulation potential is based on data of the structure-related substance ‘Oligomerisation and alkylation reaction products of 2-phenylpropene and phenol’ (OAPP) [EC no. 700-960-7] and on data of one of its constituents. OAPP is similar to NAF-AO in so far as both substances have essential components in common (aryl-aliphatic oligomerisation products - dimers, trimers). 2,4-diphenyl-4-methyl-1-pentene is one of these dimers.

Bioaccumulation: aquatic / sediment

In a feeding study according to OECD TG 305 (Klix/NOACK 2017) with the test substance OAPP, biomagnification factors were determined for the dimeric and trimeric constituents of OAPP. During the uptake phase and the depuration phase, the concentration of dimers and trimers were analysed as sum parameter. After evaluation of the kinetic data, lipid-normalised BMF of 0.0737 and 0.1374 were determined for the group of dimeric and trimeric constituents, respectively. Corresponding half-lives were 5.3 and 25.8 days.

2,4-diphenyl-4-methyl-1-pentene was examined in a reliable study following a Japanese protocol similar to OECD TG 305 (MOE/NITE 2002). Aqueous exposure for 60 days at two exposure levels (1 and 10 µ/L) was followed by a depuration phase of 14 days. After normalisation of the measured values to a lipid content of 5% for each individual fish, the mean BCF values of two replicates were as follows:

High exposure group: 2019 (day 42) / 3204 (day 60)

Low Exposure group: 3883 (day 42) / 1743 (day 60).

Average from day 42 to day 60 for both groups were 2302 (high exposure) and 2767 (low exposure).

Elimination half-lives (as DT50) were given as 4.5 d (high exposure) and as 15.7 d (low exposure). The higher value (low exposure) seems to be erroneous, which is indicated by re-examination of the kinetic data in the report and by comparison with half-life determine d for dimers.

Bioaccumulation: terrestrial

No data available (not required for REACH)

 

Transport and distribution

Adsorption/Desorption

NAF-AO contains components with high log Pows ranging from about 6.5 to above 10. Corresponding adsorption constant (log Koc values), estimated from these log Pow values in a first approach by (Q)SAR range from about 10E5 to about 10E8 to 10E9. Moreover, water solubility is low. These properties indicate high adsorption to solid matter and low mobility in the environment.

Henry’s Law constant

Henry’s Law constant H was estimated to be 9.0 Pa*m³/mol using measured parameters of NAF-AO (vapour pressure and water solubility) and an average molecular weight of 300 for the substance.