Nitriles, C16-18 and C18-unsatd.

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

06 April 2023

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
EPI Suite v4.11

2. MODEL (incl. version number)
BCFBAF v3.01

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL

Only constituents that are present at ≥2% w/w were considered in the fragment-based calculations.

Tetradecanenitrile,
CAS no.: 629-63-0
SMILES: CCCCCCCCCCCCCC#N

Hexadecanenitrile
CAS no.: 629-79-8
SMILES: CCCCCCCCCCCCCCCC#N

Octadecanenitrile
CAS no.: 638-65-3
SMILES: CCCCCCCCCCCCCCCCCC#N

(Z)-Octadec-9-enenitrile
CAS no.: 112-91-4
SMILES: CCCCCCCCC=CCCCCCCCC#N

Alkylnitrile Content BCF contribution to weighted average
14 3.8 121.6 4.6
16 35.3 540.9 190.9
18 16.9 1509 255.0
18' 39.5 1929 762.0
Weighted average Arneel T 1212.5


4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
- Defined endpoint: Bioconcentration factor in Fish
- Unambiguous algorithm: see the method description attached
- Defined domain of applicability: see the method description attached
- Appropriate measures of goodness-of-fit and robustness and predictivity: see the method description attached
- Mechanistic interpretation: see the method description attached
The BCF values selected for the BCF training and validation datasets are available via: http://esc.syrres.com/interkow/EpiSuiteData.htm

5. APPLICABILITY DOMAIN
- Model domain: Currently there is no universally accepted definition of model domain. However, users may wish to consider the possibility that Organic carbon/water partition coefficient estimates are less accurate for compounds outside the MW and log Kow ranges of the training set compounds, and/or that have more instances of a given correction factor than the maximum for all training set compounds. In general, the intended application domain for all models embedded in EPISuite is organic chemicals.
The training set molecular weights are within the range of 68.08 to 991.8 with an average molecular weight of 244 , the log Kow values range from -6.50 to 11.26.

- Mechanistic domain:
The BCFBAF QSAR classifies a compound as either ionic or non-ionic. Ionic compounds include carboxylic acids, sulfonic acids and salts of sulfonic acids, and charged nitrogen compounds (nitrogen with a +5 valence such as quaternary ammonium compounds). All other compounds are classified as non-ionic.

- Similarity with analogues in the training set:
Unknown

- Other considerations (as appropriate):
-

6. ADEQUACY OF THE RESULT
The calculated average value calculated from the main fragments of the substance is adequate as all fragments fall within the applicability domain of the model.

Guideline:

other: REACH Guidance on QSARs R.6

Principles of method if other than guideline:

see attached documentation

GLP compliance:

no

Key result

Temp.:

ca. 25 °C

Type:

BCF

Value:

ca. 1 212 L/kg

Basis:

whole body w.w.

Calculation basis:

other: Arnot-Gobas

Remarks on result:

other: Conc.in environment / dose:not relevant

Executive summary:

No actual data are available for characterizing the bioaccumulation in fish in the substance. Modelled data are therefore considered to assess this parameter. As the substance is readily biodegradable it is also expected to quickly metabolise in fish liver S9 fractions, the Arnot-Gobas calculation including biotreansformation rate estimate have been taken into account. The result obtained indicates that the estimated Bioaccumulation Factor (BAF) of the substance is 1212 L/kg, calculated from its major constituents. On this basis it can be assumed that the substance will have a low to moderate bioaccumulation potential

Description of key information

No actual data are available for characterizing the bioaccumulation in fish in the substance. Modelled data are therefore considered to assess this parameter. As the substance is readily biodegradable it is also expected to quickly metabolise in fish liver S9 fractions, the Arnot-Gobas calculation including biotreansformation rate estimate have been taken into account. The result obtained indicates that the estimated Bioaccumulation Factor (BAF) of the substance is 1212 L/kg, calculated from its major constituents. On this basis it can be assumed that the substance will have a low to moderate bioaccumulation potential.