N-(2-ethylhexyl)-8,9,10-trinorborn-5-ene-2,3-dicarboximide

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

18 July 1991 to 17 Dec 1992

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: U.S. EPA FIFRA N-163-1 and 40 CFR, Sec. 158.130

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 106 (Adsorption - Desorption Using a Batch Equilibrium Method)

GLP compliance:

yes

Remarks:

soil characterization data supplied by A&L Laboratories cannot be verified for complying with the current Good Laboratory Practice standards.

Type of method:

batch equilibrium method

Media:

soil

Specific details on test material used for the study:

[Hexyl-1-14C]-MGK264: Purity - 98%;

Radiolabelling:

yes

Test temperature:

25 +/- 1 °C

Analytical monitoring:

yes

Details on sampling:

Nominal Concentrations for all 4 soils Definitive test: 0.1, 0.25, 0.5 and 1.0 ppm
Liquid scintillation counting analysis was used to measure the test material concentrations in the aqueous phases. The amount of 14C-test material remaining adsorbed on the soil was determined by combustion-radioanalysis.

Matrix no.:

#1

Matrix type:

clay loam

% Clay:

ca. 38

% Silt:

ca. 40

% Sand:

ca. 22

% Org. carbon:

ca. 0.65

pH:

ca. 6.4

CEC:

ca. 19.6 meq/100 g soil d.w.

Bulk density (g/cm³):

ca. 1.38

Matrix no.:

#2

Matrix type:

silt loam

% Clay:

ca. 24

% Silt:

ca. 52

% Sand:

ca. 24

% Org. carbon:

ca. 2.1

pH:

ca. 7.4

CEC:

ca. 22.7 meq/100 g soil d.w.

Bulk density (g/cm³):

ca. 1.08

Matrix no.:

#3

Matrix type:

sand

% Clay:

ca. 4

% Silt:

ca. 4

% Sand:

ca. 92

% Org. carbon:

ca. 0.25

pH:

ca. 7.4

CEC:

ca. 0.3 meq/100 g soil d.w.

Bulk density (g/cm³):

ca. 1.64

Matrix no.:

#4

Matrix type:

sandy loam

% Clay:

ca. 13

% Silt:

ca. 28

% Sand:

ca. 59

% Org. carbon:

ca. 0.35

pH:

ca. 8.5

CEC:

ca. 19.8 meq/100 g soil d.w.

Bulk density (g/cm³):

ca. 1.16

Details on matrix:

Test Soils
ABC Laboratories, Inc., Columbia, Missouri, supplied the #1 clay loam, #2
silt loam, #3 sand, and #4 sandy loam. Representative subsamples of the #1
clay loam, #2 silt loam, and #3 sand were shipped to A & L Mid West
Agricultural Laboratories, Inc., 13611 B Street, Omaha, Nebraska, for
characterization. A representative subsample of the #4 sandy loam soil was
shipped to AGVISE, Highway 15, Northwoods, North Dakota, for
characterization

Details on test conditions:

Preliminary: 1ppm concentration and 1:10 soil:solution ratio used for each soil
Duplicates of each soil sampled at 2, 4, 6, 24 and 48 hours. Kd values suggest 4 hr was optimum adsorption equilibrium for #3 and 6 hr for soils #1 #,2 and #4

Computational methods:

Adsorption properties can be characterized by the Freundlich isotherm:
x/m = k Ce^(1/n) or ln x/m = ln kd + 1/n ln Ce
where:
x = the amount of chemical adsorbed in μg
m = mass of adsorbent in grams, dry soil equivalent weight (l.000 g)
ln = natural logarithm

when in equilibrium with an aqueous solution, where:
Ce = concentration of chemical in aqueous solution in μg/mL
k = Freundlich adsorption coefficient
n = a constant
The Freundlich isotherm given as ln x/m = ln k + l/n ln Ce is in the
form of a line equation. Calculations were made of x/m, ln Ce, and ln
x/m. From these data, ln Ce was plotted versus ln x/m. The line
equations for the adsorption isotherm for each of the three sediment types
were determined by linear regression analysis (Table XV). The constants
k and n were determined for each sediment type from the slope (l/n) and
y-intercept (ln k) of the corresponding line equation. The adsorption
constant K0c for each sediment type was determined by using the equation:
Koc = (Kd / % OC) * 100
where:
% OC = the soil organic carbon content

Key result

Sample No.:

#1

Type:

Koc

Value:

ca. 3 106 dimensionless

Temp.:

25 °C

Matrix:

Clay Loam

% Org. carbon:

ca. 0.65

Key result

Sample No.:

#2

Type:

Koc

Value:

ca. 1 588 dimensionless

Temp.:

25 °C

Matrix:

Silt Loam

% Org. carbon:

ca. 2.1

Key result

Sample No.:

#3

Type:

Koc

Value:

ca. 636 dimensionless

Temp.:

25 °C

Matrix:

Sand

% Org. carbon:

ca. 0.25

Key result

Sample No.:

#4

Type:

Koc

Value:

ca. 1 555 dimensionless

Temp.:

25 °C

Matrix:

Sandy Loam

% Org. carbon:

ca. 0.35

Adsorption and desorption constants:

% Organic
Carbon Adsorption Desorption
Soil Type Kd Koc -Kd Koc
Clay Loam 0.65 20.2 3106 9.2 1419
Silt Loam 2.1 33.3 1588 9.3 441
Sand 0.25 1.6 636 10.2 4099
Sandy Loam 0.35 5.4 1555 9.8 2797

Recovery of test material:

Mean Mass balance recoveries across 5 consentrations for each soil:
Clay Loam: 101.5 % with SD = 10.3
Silt Loam: 101.6 % with SD = 3.8
Sand: 100.3 % with SD = 4.0
Sandy Loam: 98.9 % with SD = 5.2

Concentration of test substance at end of adsorption equilibration period:

Adsorbed (%)
Nominal Test Clay Loam Silt loam Sand Sandy loam
Concentration
(ppm)
0.10 75.5 83.0 9.5 34.0
0.10 58.9 82.1 7.0 32.5
0.25 79.0 82.6 13.6 36.7
0.25 72.9 81.9 9.0 32.4
0.50 69.8 80.9 9.8 36.8
0.50 70.0 80.4 10.6 31.5
1.0 70.2 80.6 16.7 40.1
1.0 67.6 79.1 12.1 33.3

Concentration of test substance at end of desorption equilibration period:

Desorbed (%)
Nominal Test Clay Loam Silt loam Sand Sandy loam
Concentration
(ppm)
0.10 14.9 10.8 11.4 23.0
0.10 16.8 10.1 11.1 23.6
0.25 14.4 10.7 9.5 21.3
0.25 15.3 10.9 10.0 20.3
0.50 15.6 11.2 9.2 20.2
0.50 15.5 11.8 11.2 21.4
1.0 15.1 11.0 8.6 18.7
1.0 16.2 12.1 8.6 21.1

Transformation products:

no

Remarks:

HPLC was used to check stability of Test item. For all 4 four soils >98% stability observed.

Details on results (Batch equilibrium method):

Soil Type % Organic % Organic Stage of Kd Koc2 n
Matter carbon study
Clay Loam 1.3 0.65 AD 20.2 3106 1.1
DE 9.2 1419 1.0
Silt Loam 4.2 2.1 AD 33.3 1588 1.1
DE 9.3 441 1.0
Sand 0.5 0.25 AD 1.6 636 0.8
DE 10.2 4099 1.0
Sandy Loam 0.7 0.35 AD 5.4 1555 1.0
DE 9.8 2797 1.0

Statistics:

Adsorption properties can be characterized by the Freundlich isotherm:
x/m = k Ce^(1/n) or ln x/m = ln kd + 1/n ln Ce
where:
x = the amount of chemical adsorbed in μg
m = mass of adsorbent in grams, dry soil equivalent weight (l.000 g)
ln = natural logarithm

when in equilibrium with an aqueous solution, where:
Ce = concentration of chemical in aqueous solution in μg/mL
k = Freundlich adsorption coefficient
n = a constant
The Freundlich isotherm given as ln x/m = ln k + l/n ln Ce is in the
form of a line equation. Calculations were made of x/m, ln Ce, and ln
x/m. From these data, ln Ce was plotted versus ln x/m. The line
equations for the adsorption isotherm for each of the three sediment types
were determined by linear regression analysis (Table XV). The constants
k and n were determined for each sediment type from the slope (l/n) and
y-intercept (ln k) of the corresponding line equation. The adsorption
constant K0c for each sediment type was determined by using the equation:
Koc = (Kd / % OC) * 100
where:
% OC = the soil organic carbon content

Adsorption Isotherm Data of MGK264 with Clay Loam

			µgin	µgin Solution
Nominal			Solution	After	µg of
Concentration(ppm)	Replicate Number	Ce(ppm)2	atInitiation	AdsorptionPhase	Compound Adsorbed	x/m	lnCe	ln x/m
0.10	I	0.02	0.90	0.23	0.67	0.67	-3.73	-0.39
0.10	II	0.04	0.90	0.37	0.53	0.53	-3.24	-0.63
0.25	I	0.05	2.41	0.51	1.91	1.91	-2.94	0.65
0.25	II	0.07	2.41	0.65	1.76	1.76	-2.68	0.56
0.50	I	0.15	4.83	1.46	3.37	3.37	-1.88	1.22
0.50	II	0.15	4.83	1.45	3.38	3.38	-1.87	1.22
1.0	I	0.31	9.92	2.95	6.97	6.97	-1.16	1.94
1.0	II	0.34	9.92	3.21	6.71	6.71	-1.09	1.90

Desorption Data of Clay Loam

Nominal			Solution	After	Solution
Concentration	Replicate	Ce	at	Adsorption	AfterDesorption
(ppm)	Number	(ppm)2	Initiation	Phase	Phase          x/m	ln Ce	ln x/m

0.10	I	0.01	0.90	0.23	0.14	0.14	-4.24	-2.00
0.10	II	0.02	0.90	0.37	0.15	0.15	-4.12	-1.89
0.25	I	0.04	2.41	0.51	0.35	0.35	-3.28	-1.06
0.25	II	0.04	2.41	0.65	0.37	0.37	-3.25	-1.00
0.50	I	0.08	4.83	1.46	0.75	0.75	-2.51	-0.28
0.50	II	0.08	4.83	1.45	0.75	0.75	-2.50	-0.29
1.0	I	0.16	9.92	2.95	1.49	1.49	-1.83	0.40
1.0	II	0.17	9.92	3.21	1.61	1.61	-1.76	0.48

Adsorption Isotherm Data of MGK264 with Silt Loam

			µgin	µginSolution
Nominal			Solution	After	µgof
Concentration(ppm)	ReplicateNumber	Ce(ppm)2	atInitiation	AdsorptionPhase	CompoundAdsorbed	x/m	ln Ce	lnx/m
0.10	I	0.02	0.90	0.15	0.75	0.75	-4.11	-0.29
0.10	II	0.02	0.90	0.16	0.74	0.74	-4.07	-0.30
0.25	I	0.04	2.41	0.42	1.99	1.99	-3.11	0.69
0.25	II	0.05	2.41	0.44	1.97	1.97	-3.07	0.68
0.50	I	0.10	4.83	0.92	3.91	3.91	-2.32	1.36
0.50	II	0.10	4.83	0.95	3.88	3.88	-2.31	1.36
1.0	I	0.20	9.92	1.93	7.99	7.99	-1.59	2.08
1.0	II	0.22	9.92	2.07	7.85	7.85	-1.51	2.06

Desorption Data of Silt Loam

			µgm	µg Removed	µg in Solution
Nominal Concentration	Replicate		Solutionat	AfterAdsorption	AfterDesorption
(ppm)	Number	Ce(ppm)2	Initiation	Phase	Phase	x/m	ln Ce	lnx/m
0.10	I	0.01	0.90	0.15	0.10	0.10	-4.56	-2.33
0.10	II	0.01	0.90	0.16	0.09	0.09	-4.64	-2.39
0.25	I	0.03	2.41	0.42	0.26	0.26	-3.59	-1.36
0.25	II	0.03	2.41	0.44	0.26	0.26	-3.56	-1.33
0.50	I	0.06	4.83	0.92	0.54	0.54	-2.85	-0.62
0.50	II	0.06	4.83	0.95	0.57	0.57	-2.80	-0.56
1.0	I	0.12	9.92	1.93	1.09	1.09	-2.15	0.09
1.0	II	0.13	9.92	2.07	1.20	1.20	-2.05	0.18

Adsorption Isotherm Data of MGK264 with Sand

			µg in	µg in Solution
Nominal Concentration	Replicate		Solution at	After Adsorption	µg of Compound
(ppm)	Number	Ce(ppm)b	Initiation	Phase	Adsorbed	x/m	ln Ce	ln x/m
0.10	I	0.08	0.90	0.82	0.09	0.09	-2.49	-2.46
0.10	II	0.08	0.90	0.84	0.06	0.06	-2.47	-2.76
0.25	I	0.21	2.41	2.08	0.33	0.33	-1.56	-1.12
0.25	II	0.22	2.41	2.19	0.22	0.22	-1.51	-1.53
0.50	I	0.44	4.83	4.36	0.47	0.47	-0.83	-0.75
0.50	II	0.44	4.83	4.32	0.51	0.51	-0.83	-0.67
1.0	I	0.83	9.92	8.26	1.66	1.66	-0.18	0.51
1.0	II	0.88	9.92	8.72	1.20	1.20	-0.13	0.19

 

Desorption Data of Sand

Nominal Concentration (ppm)	Replicate Number	Ce (ppm)2	µg in Solution at Initiation	µg Removed After Adsorption Phase	µg in Solution After Desorption Phase	x/m	ln Ce	ln x/m
0.10	I	0.01	0.90	0.82	0.10	0.10	-4.53	-2.27
0.10	II	0.01	0.90	0.84	0.10	0.10	-4.59	-2.30
0.25	I	0.02	2.41	2.08	0.23	0.23	-3.76	-1.47
0.25	II	0.02	2.41	2.19	0.24	0.24	-3.72	-1.42
0.50	I	0.04	4.83	4.36	0.44	0.44	-3.12	-0.81
0.50	II	0.05	4.83	4.32	0.54	0.54	-2.90	-0.61
0.75	I	0.09	9.92	8.26	0.85	0.85	-2.46	-0.17
0.75	II	0.09	9.92	8.72	0.86	0.86	-2.46	-0.16

 

Adsorption Isotherm Data of MGK264 with Sandy Loam

			µg in	µg in Solution
Nominal			Solution	After	µg of
Concentration (ppm)	ReplicateNumber	Ce(ppm)2	atInitiation	AdsorptionPhase	CompoundAdsorbed	x/m	1n Ce	ln x/m
0.10	I	0.06	0.90	0.60	0.31	0.31	-2.79	-1.18
0.10	II	0.06	0.90	0.61	0.29	0.29	-2.78	-1.22
0.25	I	0.16	2.41	1.53	0.88	0.88	-1.86	-0.12
0.25	II	0.16	2.41	1.63	0.78	0.78	-1.80	-0.25
0.50	I	0.32	4.83	3.05	1.78	1.78	-1.14	0.58
0.50	II	0.34	4.83	3.31	1.52	1.52	-1.08	0.42
1.0	I	0.63	9.92	5.94	3.98	3.98	-0.46	1.38
1.0	II	0.69	9.92	6.62	3.30	3.30	-0.38	1.19

Desorption Data of Sand

NominalConcentration	Replicate		µg in Solution at	µg Removed After Adsorption	µg in SolutionAfter Desorption
(ppm)	Number	Ce(ppm)2	Initiation	Phase	Phase	x/m	lnCe	ln x/m
0.10	I	0.02	0.90	0.60	0.21	0.21	-3.82	-1.57
0.10	II	0.02	0.90	0.61	0.21	0.21	-3.81	-1.54
0.25	I	0.05	2.41	1.53	0.51	0.51	-2.93	-0.67
0.25	II	0.05	2.41	1.63	0.49	0.49	-2.97	-0.72
0.50	I	0.10	4.83	3.05	0.97	0.97	-2.26	-0.03
0.50	II	0.11	4.83	3.31	1.03	1.03	-2.23	0.03
1.0	I	0.20	9.92	5.94	1.85	1.85	-1.60	0.62
1.0	II	0.20	9.92	6.62	2.09	2.09	-1.61	0.74

 

Validity criteria fulfilled:

yes

Conclusions:

Soil Type % Organic Stage of Kd Koc2 Mobility Class
carbon study
Clay Loam 0.65 AD 20.2 3106 Slight
DE 9.2 1419
Silt Loam 2.1 AD 33.3 1588 Low
DE 9.3 441
Sand 0.25 AD 1.6 636 Low
DE 10.2 4099
Sandy Loam 0.35 AD 5.4 1555 Low

Executive summary:

An OECD 106 (Adsorption/desorption using a batch equilibrium method) study is available for MGK 264 in clay loam, silt loam, sand and sandy loam soils.

Only two of the soils fell within the desired adsorption range of 20 to 80% for the Freundlich model. However, the adsorption isotherms for all soil types showed a high degree of linear correlation for a plot of ln (Ce) versus ln (x/m). Correlation coefficients for the adsorption isotherms of soils clay loam, silt loam, sand, and sandy loam were 0.958, 0.999, 0.983, and 0.994, respectively. The correlation coefficients for the adsorption isotherms imply that all of the soils adequately fit the Freundlich model for this compound.

Desorption isotherms were calculated for all soil types. The correlation coefficients for the desorption isotherms determined for soils clay loam, silt loam, sand, and sandy loam were 1.000, 1.000, 1.000, and 0.999, respectively. The correlation coefficients for the desorption isotherms also imply that all of the soils adequately fit the Freundlich model for this compound.

The mean 14C-mass balance of the test compound for clay loam, silt loam, sand, and sandy loam was 101.5, 101.6, 100.3, and 98.9%, respectively. High-performance liquid chromatography was used to test the stability of the test compound under study conditions. The percent of parent compound observed in the adsorption phase was 99.3, 100.0, 98.6, and 98.3% for clay loam, silt loam, sand, and sandy loam, respectively.

Mean Koc over the 4 soils was 1721.25 and 2189 for desorption.

Description of key information

An OECD 106 (Adsorption/desorption using a batch equilibrium method) study is available for MGK 264 in clay loam, silt loam, sand and sandy loam soils.

Only two of the soils fell within the desired adsorption range of 20 to 80% for the Freundlich model. However, the adsorption isotherms for all soil types showed a high degree of linear correlation for a plot of ln (Ce) versus ln (x/m). Correlation coefficients for the adsorption isotherms of soils clay loam, silt loam, sand, and sandy loam were 0.958, 0.999, 0.983, and 0.994, respectively. The correlation coefficients for the adsorption isotherms imply that all of the soils adequately fit the Freundlich model for this compound.

Desorption isotherms were calculated for all soil types. The correlation coefficients for the desorption isotherms determined for soils clay loam, silt loam, sand, and sandy loam were 1.000, 1.000, 1.000, and 0.999, respectively. The correlation coefficients for the desorption isotherms also imply that all of the soils adequately fit the Freundlich model for this compound.

The mean 14C-mass balance of the test compound for clay loam, silt loam, sand, and sandy loam was 101.5, 101.6, 100.3, and 98.9%, respectively. High-performance liquid chromatography was used to test the stability of the test compound under study conditions. The percent of parent compound observed in the adsorption phase was 99.3, 100.0, 98.6, and 98.3% for clay loam, silt loam, sand, and sandy loam, respectively.

Mean Koc over the 4 soils was 1721.25 and 2189 for desorption.

Key value for chemical safety assessment

Koc at 20 °C:

1 721.25