1,2,3-trichloropropane

Adsorption / desorption

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

adsorption / desorption

Remarks:

adsorption

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The study used sound scientific methods to determine the sorption partition coefficients in two soil samples. The methods are well documented and the volatility of the test substance was taken into account in the method. Only the sorption partition coefficients for the substance and the resulting organic carbon/water partition coefficients are given, detailed results showing the measured concentrations are missing. The results nevertheless are considered as reliable with restrictions.

Principles of method if other than guideline:

The study followed principles described in the US Environmental Protection Agency "Hazardous waste management system: proposed rule, appendix I, Fed. Reg. 51, 1750-1758. In brief, sieved samples of air-dried soil were placed in a stainless steel Zero Headspace Extractor. The air was removed from the sample and solutions of the test substance were injected dissolved in 250 mL of 0.01 M aqueous calcium nitrate. The headspace was eliminated and the extractor was rotated end over end at 30 rpm for 18 hours. Samples of aqueous filtrate were withdrawn and the remaining soil cake was extracted three times with methanol. Both, aqueous and methanol filtrates were analysed for 1,2,3-trichloropropane by packed-column gas chromatography.

GLP compliance:

not specified

Type of method:

other: Zero headspace extraction

Media:

soil

Radiolabelling:

no

Test temperature:

Room temperature

Analytical monitoring:

yes

Details on sampling:

2 mL samples of aqueous filtrate were withdrawn directly into a glass syringe and transferred to 2-mL septum-sealed glass vials, which were then capped without headspace. The resultant soil cake was then extracted three times with 50 mL aliquots of methanol by rotating the extractor for 15 minutes during each extraction. Aliquots of the methanol filtrate were taken in the same manner as aqueous filtrates. Samples were stored at 4 °C until analysis.

Details on matrix:

Two soils, a Captina silt loam from Roane County, Tennessy, USA and a McLaurin sandy loam from Stone County, Mississippi, USA were used. Both soils were acidic and low in organic carbon content (Captina silt loam, pH = 4.97 and OC content = 1.49 %; McLaurin sandy loam, pH = 4.43 and OC content = 0.66 %). The soils were air-dried and sieved to 2.0 mm before experimental use.
Composition Captina loam: 7.7 % sand, 62.5 % silt, 29.9 % clay, N (g/kg) = 0.18; P (g/kg) = 0.04; S (g/kg) = 0.084
Composition McLaurin loam: 74.9 % sand, 20.4 % silt, 4.7 % clay, N (g/kg) = 1.3; P (g/kg) = 0.49; S (g/kg) = 0.186

Details on test conditions:

Sorption experiments were performed at five different concentrations of 100, 500, 550, 600 and 650 micrograms per gram of soil.

Computational methods:

The sorption partition coefficients at the specified concentrations were calculated by assuming linearity of the isotherms.

Type:

Koc

Value:

>= 77 - <= 94.7 L/kg

Type:

log Koc

Value:

>= 1.89 - <= 1.98 L/kg

Recovery of test material:

112 to 115 %

Concentration of test substance at end of adsorption equilibration period:

no data

Concentration of test substance at end of desorption equilibration period:

not applicable

Transformation products:

no

4 sorption experiments were used to calculate the sorption coefficient for the Captina silt loam resulting in a Koc value of 94.72 +/- 10.86 L/kg

8 sorption experiments were used to calculate the sorption coefficient for the McLaurin sandy loam resulting in a Koc value of 76.87 +/- 8.77 L/kg

Validity criteria fulfilled:

yes

Conclusions:

The organic carbon/water partition coefficient of 1,2,3-trichloropropane was determined in a silty and a sandy loam and ranged from 77 to 94.7 L/kg.

Executive summary:

The organic carbon/water partition coefficient of 1,2,3-trichloropropane was experimentally determined using a standardised test system with a zero headspace extractor. Two soils, the silty Captina loam and the sandy McLaurin loam, were used which both were acidic and contained low amounts of organic carbon. Sorption experiments were carried out with solutions of the substance in 250 mL of 0.01 M aqueous calcium nitrate and final concentrations of 100, 500, 550, 600 and 650 micrograms per gram of soil. The samples were contained in air-tight test tubes that were agitated for 18 hours. Two aqueous filtrates were sampled afterwards and the sand cake then was extracted three times with methanol. Aliquots from methanol filtrates were sampled. The concentrations of 1,2,3 -trichloropropane in the samples was analysed by packed-column gas chromatography. The sorption partition coefficients at the specified concentrations was calculated by assuming linear isotherms and the Koc was determined from these sorption partition coefficients by taking into account the soil content of organic carbon. The experiments resulted in a Koc in the sandy loam of 77 L/kg and in the silty loam of 94.7 L/kg.

Reference 2

Endpoint:

adsorption / desorption, other

Type of information:

(Q)SAR

Adequacy of study:

supporting study

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 limited documentation / justification

Justification for type of information:

QSAR prediction: migrated from IUCLID 5.6

Principles of method if other than guideline:

The Koc was calculated with the KOCWIN 2.0 modelling program

GLP compliance:

no

Type of method:

other: QSAR calculation

Media:

soil

Radiolabelling:

no

Test temperature:

not applicable

Type:

Koc

Value:

>= 52 - <= 116 L/kg

Type:

log Koc

Value:

>= 1.72 - <= 2.06 L/kg

Conclusions:

The modelled Koc of 1,2,3-trichloropropane using the KOCWIN 2.0 modelling program is between 52 and 116 L/kg.

Executive summary:

The organic carbon-water partitioning coefficient of 1,2,3-trichloropropane was modelled using the KOCWIN 2.0 modelling program published by the US Environmental Protection Agency. The model applies two different approaches to calculate the Koc of a substance based on the first-order molecular connectivity index and the log Kow, respectively. The thus calculated Koc of 1,2,3-trichloropropane is 116 L/kg and 52 L/kg, respectively.

Key value for chemical safety assessment

Koc at 20 °C:

77

Additional information

The adsorption/desorption behaviour of TCP was studied using silty and sandy loam (Walton et al. 1992). The KOC values resulting from the experiments were in the range of 77 to 95 indicating the low ability of the substance for adsorption. These low values show the high mobility of TCP in soil that may lead to the appearance of the substance in groundwater if release to the soil occurs. Further, the organic carbon-water partitioning coefficient (KOC) was predicted using the KOCWIN v2.0 modelling program published by the US Environmental Protection Agency. The calculated KOC values were in a range of 52-116 (Wormuth 2010a).