Fast Pyrolysis Bio-oil

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Remarks:

EPI Suite v.4.11

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Justification for type of information:

1. SOFTWARE: U.S. Environmental Protection Agency for EPI Suite™ v.4.11 and the individual programs included within the software.
http://www.epa.gov/oppt/exposure/pubs/episuite.htm

2. MODEL: The Soil Adsorption Coefficient Program (KOCWIN) estimates the soil adsorption coefficient (Koc) of organic compounds.

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
The study is based on eight representative components of the test material.

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
The link: https://www.epa.gov/tsca-screening-tools/epi-suitetm-estimation-program-interface

EPI Suite (TM): Individual estimation programs and/or their underlying predictive methods and equations have been described in numerous journal articles in peer-reviewed technical journals. In addition, EPI Suite™ has undergone detailed review by a panel of EPA’s independent Science Advisory Board.

- Defined endpoint: adsorption/desorption

- Unambiguous algorithm:
KOCWIN™: Formerly called PCKOCWIN™, this program estimates the organic carbon-normalized sorption coefficient for soil and sediment; i.e. KOC. KOC is estimated using two different models: the Sabljic molecular connectivity method with improved correction factors; and the traditional method based on log KOW.
A traditional method of estimating soil adsorption Koc involves correlations developed with log octanol-water partition coefficient (log Kow) (Doucette, 2000). A companion document (Methodology) also discusses the methodology. Also validation results are presented in the Attachment.

5. APPLICABILITY DOMAIN

The modelled representative compounds are organic substances covered by the applicability domain of KOCWIN.

Molecular weights of the representative components (test material) are within the Molecular Weight minimum and maximum values for Training Set (32.04 – 665.02) and Validation range (73.14 – 504.12).

Selected Koc values for 674 compounds were used to train and validate the updated regression from these sources:
(1) Schuurmann et al. (2006) compilation: 453 compounds,
(2) Original PCKOCWIN regression: 85 compounds,
(3) USDA Pesticide Properties Database: 85 compounds,
(4) Average from multiple sources: 21 compounds,
(5) Miscellaneous sources: 30 compounds (Nguyen et al, 2005; Sabljic et al, 1995; Baker et al, 1997; VonOepen et al, 1991; Kaune, 1998; Gawlik et al, 1998; HSBD, 2008).

The 674 compounds were eventually divided into a training set of 516 compounds and a validation set of 158 compounds. The training set was divided further into a dataset of 69 non-polar organics and 447 polar organics (same as previously described in Meylan et al, 1992). For the current model development, the non-polar dataset is designated as compounds having “No Correction Factors” while the polar compounds are designated as compounds “Having Correction factors”.

6. ADEQUACY OF THE RESULT

Accuracy of the calculated logKoc parameters (MCI method) versus experimental results of the representative compounds are as follows, respectively:
Acetaldehyde: 1 ; -,
Acetic acid: 1; 0,
b-Sitosterol: 6.686; -,
Furfural: 0.784; -,
Glucose; 1; -,
Methanol; 0; 0.44,
Naphthalene; 3.189; 2.96,
Phenol; 2.272; 1.9
(Attachment: KOCWIN Results).

Due to the nature of bio-oils, which as UVCB substance consists of more than 500 different compounds, it is technically irrelevant to test partition coefficient for the substance. Therefore, the computational method gives a reasonably reliable estimate on the weighted average of the parameter.


REFERENCES:

Doucette, W.J. 2000. Soil and sediment sorption coefficients. In: Handbook of Property Estimation Methods, Environmental and Health Sciences. R.S. Boethling & D. Mackay (Eds.), Boca Raton, FL: Lewis Publishers (ISBN 1-56670-456-1).

Guideline:

other: REACH Guidance on QSARs R.6

Type of method:

other: EPIWIN Modelling, the model used: KOCWIN

Specific details on test material used for the study:

PHYSICAL-CHEMICAL PROPERTIES MODELLED WITH EPIWIN
v.4.11

Compound CAS number

Acetic acid CAS no 64-19-7;
Methanol CAS no 67-56-1;
Phenol CAS no 108-95-2;
Acetaldehyde CAS no 75-07-0;
Furfural CAS no 98-01-1;
Glucose CAS no 50-99-7;
Naphthalene CAS no 91-20-3;
Beta-sitosterol CAS no 83-46-5.

Test material, UVCB substance, consists of more than 500 different compounds such as long-chain fatty acids, PAHs, sesquiterpenes (Jenner et al., 2011), and phytosterols (Hewitt et al., 2000).
According to analytical data, such compounds may form ca. 4 % of FPBO in total.

REFERENCES
Hewitt, L.M., Parrot, J.L., Weells, K.L., Calp, M.K., Biddiscombe, S., McMaster, M.E., Munkittrick, K.R., van der Kraak, G., 2000. Characteristics of ligands for the Ah receptor and sex steroid receptors in hepatic tissues of fish exposed to bleached kraft mill effluent. Environ Sci Technol 34:4327-4334.

Type:

Koc

Remarks:

Modelled with EPIWIN

Value:

8 189.63 L/kg

Remarks on result:

other: Soil adsorption coefficients of the individual components range from 0.01658 to 7.10E+05 with the weighted average being 8189.63 l/kg.

TABLE 1. Koc (l/kg)

PHYSICAL-CHEMICAL PROPERTIES MODELLED WITH EPIWIN
v.4.11
	Compound	FPBO, ww-%	MW (g/mol)	Koc (l/kg)
	acetic acid	2.9	60.05	1.153
	methanol	0.41	32.04	1.224
	phenol	0.42	94.11	79.34
	acetaldehyde	0.05	44.05	3.219
	furfural	0.15	96.09	8.368
	glucose	0.96	180.16	0.01658
	naphthalene	0.00079	128.18	730.6
	beta sitosterol	0.057	414.72	7.10E+05
Weighted average			88.95	8189.63
Average			131.175	88877.99

---------------------------

Molecular weight, MW

Soil Adsorption Coefficient (KOCWIN v2.00), Koc, Kow method

Conclusions:

Soil adsorption coefficients (Koc, l/kg) of individual eight compounds range from 0.01658 to 7.10E+05 with the weighted average being 8189.63 l/kg.

Executive summary:

Soil adsorption coefficients (Koc, l/kg) of the main components (contributing 5 % of the total wet weight) were determined using KOCWIN program developed by U.S. Environmental Protection Agency. Soil adsorption coefficients of the individual components range from 0.01658 to 7.10E+05 with the weighted average being 8189.63 l/kg.

Description of key information

Soil adsorption coefficients (Koc, l/kg) of the main components (contributing 5 % of the total wet weight) were determined using KOCWIN program developed by U.S. Environmental Protection Agency. Soil adsorption coefficients of the individual components range from 0.01658 to 7.10E+05 with the weighted average being 8189.63 l/kg.

Key value for chemical safety assessment

Koc at 20 °C:

8 189.63

Additional information

While the sorption of specific compounds to solid surfaces and matter is difficult to predict, the lipophilicity of organic compounds (log K_ow) is in general a good predictor of their tendency to be sorbed (either adsorbed or absorbed) to generic organic matter, so that lipophilic compounds such as fatty acids, triglycerides, sterols, resin acids, sesquiterpenes and PAHs are those most likely affected. PAHs may also be strongly adsorbed to so-called carbonaceous geosorbents such as soot and charcoal (Koelmans et al., 2006). According to analytical data, such compounds may form ca. 6 % of FPBO in total.

REFERENCES

Koelmans, A.A., Jonker, M.T.O., Cornelissen, G., Bucheli, T.D., van Noort, P.C.M., Gustafsson, Ö., 2006. Black carbon: the reverse of its dark side. Chemosphere 63, 365-377