1,1'-(ethane-1,2-diyl)bis[pentabromobenzene]

Biodegradation in soil

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in soil: simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

August 2013 - February 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 307 (Aerobic and Anaerobic Transformation in Soil)

GLP compliance:

yes (incl. QA statement)

Test type:

laboratory

Specific details on test material used for the study:

The radio-labeled test substance, [14C]DBDPEthane, was received from Perkin Elmer on February 23,
2010, and assigned Wildlife International identification number 9412. The test substance was supplied in
solid form, and was identified as 1,2-Bis[pentabromophenyl]ethane, [Phenyl-14C[U]];
CUSC72819000MC; lot number 3626190. Information provided by the supplier indicated the
radiochemical purity was 94.5%, the specific activity was 32.4 mCi/mmol, and the molecular weight was
972 mg/mmol. A total of 14.0 mCi was supplied, and no expiration date was provided. The test substance was stored in
a freezer set to approximately -20 C. Albemarle Corporation’s trade name for this substance is SAYTEX®
8010 Flame Retardant.

Radiolabelling:

yes

Oxygen conditions:

aerobic

Soil classification:

USDA (US Department of Agriculture)

Year:

2013

Soil no.:

#1

Soil type:

loamy sand

% Clay:

9

% Silt:

9

% Sand:

82

% Org. C:

0.9

pH:

5.2

CEC:

10.2 meq/100 g soil d.w.

Bulk density (g/cm³):

1.16

Soil no.:

#2

Soil type:

sandy clay loam

% Clay:

21

% Silt:

13

% Sand:

66

% Org. C:

1.9

pH:

6.9

CEC:

17.9 meq/100 g soil d.w.

Bulk density (g/cm³):

1.04

Soil no.:

#3

Soil type:

clay loam

% Clay:

29

% Silt:

27

% Sand:

44

% Org. C:

4

pH:

5.4

CEC:

31.4 meq/100 g soil d.w.

Bulk density (g/cm³):

0.99

Soil no.:

#4

Soil type:

sandy clay loam

% Clay:

29

% Silt:

23

% Sand:

48

% Org. C:

2.8

pH:

7.9

CEC:

68.8 meq/100 g soil d.w.

Bulk density (g/cm³):

1.01

Details on soil characteristics:

The four soils used in this study were supplied by Agvise Laboratories (Northwood, North Dakota,
USA). The soils were collected from four different sites on July 24, 2013. The soils were collected to a depth
of approximately 0-15 cm using a shovel, and sieved through a 2-mm screen. Samples were analyzed by
Agvise Labs to determine textural class, bulk density, cation exchange capacity, moisture content at 1/3 bar,
organic carbon content, pH, concentrations of selected cations, microbial biomass, and ferrous iron content.
Copies of the characterization reports are presented in Appendix III. The soils were received at Wildlife
International on August 7, 2013, and stored in a walk-in cooler set at approximately 5 degrees C.
The soils were selected to be consistent with the referenced OECD test guideline [1], and representative
of different agricultural soil types. The guideline calls for the use of a representative soil with one of four
textural classifications, a pH of 5.5 to 8.0, an organic carbon content of 0.5% to 2.5%, and a microbial
biomass of at least 1% of total organic carbon content. Soil 2 listed above (MSL-PF, sandy clay loam)
matched this description. The other soils provided a variety of organic carbon content, pH, clay content and
microbial biomass.

The water holding capacities and moisture contents of the soils were determined by Wildlife
International, prior to use in the study. The properties of all four soils are presented in Table 1.

Soil No.:

#1

Duration:

182 d

Soil No.:

#2

Duration:

182 d

Soil No.:

#3

Duration:

182 d

Soil No.:

#4

Duration:

182 d

Soil No.:

#1

Initial conc.:

1.8 mg/kg soil d.w.

Based on:

test mat.

Soil No.:

#2

Initial conc.:

1.8 mg/kg soil d.w.

Based on:

test mat.

Soil No.:

#3

Initial conc.:

1.8 mg/kg soil d.w.

Based on:

test mat.

Soil No.:

#4

Initial conc.:

1.8 mg/kg soil d.w.

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

radiochem. meas.

Soil No.:

#1

Temp.:

20 C

Humidity:

14.6% moisture content @ 1/3 bar

Microbial biomass:

211.7 ug/g

Soil No.:

#2

Temp.:

20 C

Humidity:

25.5% moisture content @ 1/3 bar

Microbial biomass:

543.2 ug/g

Soil No.:

#3

Temp.:

20 C

Humidity:

35.2% moisture content @ 1/3 bar

Microbial biomass:

531.5 ug/g

Soil No.:

#4

Temp.:

20 C

Humidity:

33.5% moisture content @ 1/3 bar

Microbial biomass:

548.3 ug/g

Soil No.:

#1

% Recovery:

94

Soil No.:

#2

% Recovery:

94

Soil No.:

#3

% Recovery:

94

Soil No.:

#4

% Recovery:

94

Key result

Soil No.:

#1

DT50:

> 6 mo

Type:

(pseudo-)first order (= half-life)

Temp.:

>= 18.3 - <= 22 °C

Key result

Soil No.:

#2

DT50:

> 6 mo

Type:

(pseudo-)first order (= half-life)

Temp.:

>= 18.3 - <= 22 °C

Key result

Soil No.:

#3

DT50:

> 6 mo

Type:

(pseudo-)first order (= half-life)

Temp.:

>= 18.3 - <= 22 °C

Key result

Soil No.:

#4

DT50:

> 6 mo

Type:

(pseudo-)first order (= half-life)

Temp.:

>= 18.3 - <= 22 °C

Transformation products:

no

Details on transformation products:

Through all test intervals, the mean maximum percentages of radioactivity recovered as other
products were 3.4%, 3.5%, 2.5% and 2.7% for soils 1, 2, 3 and 4, respectively. The amount of impurities
in the test substance applied to the soils was 5.5%, based on the certificate of analysis. The other
products observed in the soil extracts were attributed to impurities in the test substance, rather than
transformation products. There were no distinct, consistent transformation product peaks observed during
the study.

Details on results:

DBDPEthane did not appear to degrade in any of the four soils. The mean percentage of
radioactivity recovered as DBDPEthane at the end of the 6-month test was >94% in all soil extracts.
There was no clear pattern of decline, and the half-lives were extrapolated well beyond the 6-month test
period. The DT50 values were >6 months for all four soils.

Table 3. Mean Cumulative Radioactivity in All Transformation Vessel Gas Traps

Test Soil	Interval (Days)	Evolved 14CO2 (%)	Volatile 14C Gases (%)	Total Gases (%)
Soil 1	32 61 91 120 152 182	0.00 0.00 0.01 0.01 0.01 0.01	0.00 0.00 0.00 0.00 0.00 0.00	0.00 0.00 0.01 0.01 0.01 0.02
Soil 2	32 61 91 120 152 182	0.00 0.00 0.01 0.01 0.01 0.01	0.00 0.00 0.00 0.00 0.00 0.00	0.00 0.00 0.01 0.01 0.01 0.01
Soil 3	32 61 91 120 152 182	0.00 0.00 0.01 0.01 0.01 0.01	0.00 0.00 0.00 0.00 0.00 0.01	0.00 0.00 0.01 0.01 0.01 0.02
Soil 4	32 61 91 120 152 182	0.00 0.00 0.01 0.01 0.01 0.01	0.00 0.00 0.00 0.00 0.00 0.00	0.00 0.00 0.01 0.01 0.01 0.01

 

Table 4. Mean Cumulative Radioactivity in All Mineralization Vessel Gas Traps

Test Soil	Interval (Days)	Evolved 14CO2 (%)	Volatile 14C Gases (%)	Total Gases (%)
Soil 1	32 61 91 120 152 182	0.00 0.01 0.02 0.03 0.03 0.04	0.00 0.01 0.02 0.02 0.03 0.04	0.00 0.02 0.03 0.05 0.06 0.08
Soil 2	32 61 91 120 152 182	0.00 0.00 0.01 0.02 0.03 0.03	0.01 0.01 0.02 0.02 0.03 0.04	0.01 0.01 0.03 0.05 0.06 0.07
Soil 3	32 61 91 120 152 182	0.00 0.00 0.01 0.01 0.02 0.03	0.00 0.01 0.01 0.02 0.03 0.03	0.00 0.01 0.02 0.04 0.05 0.06
Soil 4	32 61 91 120 152 182	0.00 0.01 0.02 0.02 0.03 0.04	0.00 0.01 0.01 0.02 0.03 0.03	0.00 0.01 0.03 0.04 0.06 0.07

 

Table 5. Mean Distribution of Radioactivity from Test Vessels

Test Soil	Interval (Days)	MeOH Extracts (%)	THF Extracts (%)	Combusted Soil Solids (%)	Total Gases (%)	Material Balance (Recovery %)
Soil 1             Mineral	0 32 61 91 120 152 182 182	1.3 1.0 1.0 0.9 0.8 0.9 0.8 0.8	98.5 107.8 103.0 103.9 105.9 101.9 104.6 93.9	1.6 1.8 1.6 1.3 1.3 1.0 5.4 1.6	NA 0.0 0.0 0.0 0.0 0.0 0.0 0.1	101.4 110.7 105.6 106.1 108.0 103.9 110.8 96.3
Soil 2             Mineral	0 32 61 91 120 152 182 182	0.4 0.3 0.5 0.4 0.3 0.4 0.4 0.4	93.6 108.8 95.4 96.2 95.4 99.8 98.6 92.2	2.9 3.5 3.0 3.4 4.0 2.4 3.1 3.1	NA 0.0 0.0 0.0 0.0 0.0 0.0 0.1	96.8 112.6 98.8 99.9 99.7 102.6 102.1 95.8
Soil 3             Mineral	0 32 61 91 120 152 182 182	0.2 0.2 0.1 0.2 0.2 0.2 0.1 0.1	93.5 105.4 95.5 96.3 98.3 91.5 88.6 96.5	3.7 2.9 3.6 3.7 4.7 4.1 3.4 4.2	NA 0.0 0.0 0.0 0.0 0.0 0.0 0.1	97.4 108.4 99.2 100.1 103.1 95.7 92.2 100.9
Soil 4             Mineral	0 32 61 91 120 152 182 182	0.4 0.3 0.3 0.5 0.3 0.4 0.3 0.3	83.3 96.3 88.6 85.8 90.9 83.7 87.6 103.1	3.2 3.0 3.3 2.7 3.8 3.1 3.2 4.3	NA 0.0 0.0 0.0 0.0 0.0 0.0 0.1	86.9 99.6 92.3 89.0 95.1 87.2 91.1 107.8

NA - Not Applicable 

Table 6. Mean Soil Extraction Efficiencies

Test Soil	Interval (Days)	Mean DPM in Comb. Soil Extracts	Mean DPM in Soil Solids	Mean DPM in Soil Sample	Proportion In/on Solids (%)	Mean Extraction Efficiency (%)
Soil 1             Mineral	0 32 61 91 120 152 182 182	13357268 14786908 14036384 14084677 14471119 13880357 14224357 12810752	218362 247916 219841 180842 176536 138208 733230 212827	13575631 15034824 14256225 14265519 14647655 14018565 14957587 13023579	1.6 1.6 1.5 1.3 1.2 1.0 4.9 1.6	98.4 98.4 98.5 98.7 98.8 99.0 95.1 98.4
Soil 2             Mineral	0 32 61 91 120 152 182 182	12621684 14704700 12935449 13029508 12883069 13488774 13325476 12385438	385028 467400 403618 451873 535071 329862 414394 418881	13006712 15172100 13339068 13481380 134181140 13818636 13739870 12804319	3.0 3.1 3.0 3.4 4.0 2.4 3.0 3.3	97.0 96.9 97.0 96.6 96.0 97.6 97.0 96.7
Soil 3             Mineral	0 32 61 91 120 152 182 182	12677898 14133520 12911136 13085171 13344245 12421630 11966506 12958412	500235 383182 487409 501087 630778 549186 454579 562464	13178133 14516701 13398545 13586258 13975022 12970815 12421085 13220876	3.8 2.6 3.6 3.7 4.5 4.2 3.7 4.2	96.2 97.4 96.4 96.3 95.5 95.8 96.3 95.8
Soil 4             Mineral	0 32 61 91 120 152 182 182	11207518 13070062 11985068 11631389 12283397 11287266 11829907 14021792	428190 404697 450585 363317 518115 422175 424803 587865	11635708 13474759 12435653 11994706 12801512 11709441 12254710 14609657	3.7 3.0 3.6 3.0 4.0 3.6 3.5 4.0	96.3 97.0 96.4 97.0 96.0 96.4 96.5 96.0

 

Table 7. Mean Chloroform Extraction Results

Test Soil	Interval (Days)	Mean DPM in Conc. Soil Extracts	Mean DPM in Chloroform Extracts	Mean DPM in Aqueous Fractions	Recovery %	% in Aqueous Fractions	Mean Extraction Efficiency (%)
Soil 1             Mineral	0 32 61 91 120 152 182 182	13407906 12884914 13437515 13604526 13909800 13798073 13341821 11455942	13168000 12786367 13122522 13309898 13369939 12806920 13478960 12041979	835 1755 1281 1771 6595 6892 10763 258	98.2 99.2 97.7 97.9 96.2 92.9 101.1 105.1	0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.0	100.0 100.0 100.0 100.0 100.0 99.9 99.9 100.0
Soil 2             Mineral	0 32 61 91 120 152 182 182	12556569 13104943 12310025 12669978 12686792 13505553 12681536 11157301	11814638 13195000 12053512 12142280 12231342 12751270 12784523 11585783	41484 1285 1629 1914 7432 5374 8514 184	94.5 100.7 98.0 95.9 96.5 94.5 100.9 103.8	0.3 0.0 0.0 0.0 0.1 0.0 0.1 0.0	99.7 100.0 100.0 100.0 99.9 100.0 99.9 100.0
Soil 3             Mineral	0 32 61 91 120 152 182 182	12495944 12657898 11634233 12771115 12320132 12480917 11116512 11834851	12355050 12836638 12168738 12372940 12537585 11875160 11381349 12289458	3865 1155 828 453 4696 4402 7182 398	98.9 101.4 104.6 96.9 101.8 95.2 102.5 103.8	0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.0	100.0 100.0 100.0 100.0 100.0 100.0 99.9 100.0
Soil 4             Mineral	0 32 61 91 120 152 182 182	11138429 11606454 11351013 11579553 11965920 11718105 11132480 12752288	10859122 12017233 11288738 11019135 11508375 11098690 11426410 13395855	8022 1203 908 509 8327 3135 7746 1182	97.6 103.5 99.4 95.2 96.3 94.7 102.7 105.1	0.1 0.0 0.0 0.0 0.1 0.0 0.1 0.0	99.9 100.0 100.0 100.0 99.9 100.0 99.9 100.0

 

Table 8. Mean Procedural Recoveries

Test Soil	Interval (Days)	Mean Recovery Combined Soil Extract Concentration (%)	Mean Recovery Chloroform Extraction (%)	Mean Recovery Chloroform Extract Concentration (%)	Overall Mean Procedural Recovery (%)
Soil 1             Mineral	0 32 61 91 120 152 182 182	107.5 92.4 99.9 100.2 100.5 102.8 97.9 95.9	98.2 99.2 97.7 97.9 96.2 92.9 101.1 105.1	108.6 102.7 103.2 106.8 112.9 109.6 121.5 98.2	114.7 94.3 100.7 104.8 109.1 104.7 120.2 99.0
Soil 2             Mineral	0 32 61 91 120 152 182 182	105.8 64.0 99.2 102.6 103.4 104.5 100.2 97.3	94.5 100.7 98.0 95.9 96.5 94.5 100.9 103.8	110.3 106.8 100.5 104.9 105.0 106.1 120.7 101.8	110.3 101.2 97.6 103.1 104.7 104.6 122.0 102.8
Soil 3             Mineral	0 32 61 91 120 152 182 182	105.2 94.0 94.1 101.5 97.2 104.2 98.0 99.7	98.9 101.4 104.6 96.9 101.8 95.2 102.5 103.8	113.1 105.4 102.2 101.7 106.5 104.8 108.8 106.6	117.7 100.4 100.5 100.0 105.3 103.9 109.3 110.4
Soil 4             Mineral	0 32 61 91 120 152 182 182	105.8 94.1 98.7 103.8 102.6 107.2 99.5 989.9	97.6 103.5 99.4 95.2 96.3 94.7 102.7 105.1	114.1 108.4 104.2 104.9 103.3 116.0 126.0 110.2	117.7 105.6 102.1 103.6 102.2 117.9 128.7 114.4

  

  

Table 9. Mean Distribution of Parent and Other ¹⁴C Products in Soil Extracts

Test Soil	Interval (Days)	Aqueous Fraction (%)	Before (1.0-11.3) (%)	Parent (11.3-12.3) (%)	After (12.3-16.0) (%)	Total % of Sample	Total % Other 14C Products
Soil 1             Mineral	0 32 61 91 120 152 182 182	0.0 0.0 0.0 0.0 0.1 0.1 0.1 0.0	0.7 0.5 0.0 0.8 0.4 1.6 0.5 0.9	94.9 96.8 97.8 96.1 96.7 96.2 94.3 96.5	2.7 1.0 0.6 1.9 1.7 1.2 0.2 0.9	98.3 98.3 98.5 98.7 98.8 99.0 95.1 98.3	3.4 1.5 0.6 2.7 2.1 2.8 0.8 1.9
Soil 2             Mineral	0 32 61 91 120 152 182 182	0.3 0.0 0.0 0.0 0.1 0.0 0.1 0.0	0.6 0.9 0.0 0.3 1.3 0.3 0.6 0.6	93.5 94.1 95.7 95.4 94.7 95.7 95.1 94.4	2.6 1.9 1.2 1.0 0.0 1.5 1.2 1.7	97.0 96.9 96.9 96.6 96.1 97.6 97.0 96.7	3.5 2.8 1.2 1.2 1.4 1.8 1.9 2.3
Soil 3             Mineral	0 32 61 91 120 152 182 182	0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.0	1.0 0.8 0.0 0.2 0.0 1.3 0.4 0.3	93.6 94.9 95.9 95.4 94.0 94.4 95.4 92.8	1.5 1.6 0.5 0.7 1.4 0.0 0.4 2.7	96.1 97.3 96.4 96.3 95.4 95.7 96.3 95.8	2.5 2.5 0.5 0.9 1.4 1.3 1.0 3.1
Soil 4             Mineral	0 32 61 91 120 152 182 182	0.1 0.0 0.0 0.0 0.1 0.0 0.1 0.0	0.6 0.8 0.0 0.1 0.1 1.2 0.6 1.0	93.9 95.1 95.1 96.5 94.6 93.7 94.2 94.5	1.8 1.2 1.3 0.4 1.1 1.5 1.7 0.5	96.4 97.0 96.4 97.0 96.0 96.4 96.6 96.0	2.5 1.9 1.3 0.5 1.4 2.7 2.3 1.5

 Total Other ¹⁴C Products = Total % of Sample - Parent

Table 10. Disappearance of DBDPEthane from Soil 1

Interval (Days)	Soil Extracts
	%	ug/kg
0 32 61 91 120 152 182	94.9 96.8 97.8 96.1 96.7 96.2 94.3	1718 1753 1771 1739 1750 1741 1706

 

Table 11. Regression Analysis of DBDPEthane in Soil 1 Extracts: Simple First-Order Model Statistics

Estimated Values:

Parameter	Value	Sigma	Prob.>t	Lower CI	Upper CI
Parent_O	96.55	0.8585	5.269E-10	94.35	87.76
K_Parent	4.993E-05	8.156E-05	0.2836	-0.0001597	0

 

Chi-Squared:

Parameter	Error %	Degrees of Freedom
All data	1.005	5
Parent	1.005	5

 

Decay Times:

Compartment	DT50 (Days)	DT90 (Days)
Parent	1.388E+04	4.612E+04

 

Additional Statistics:

Parameter	r2 (Obs. v. Pred.)	Efficiency
All data	0.07027	0.07027
Parent	0.07027	0.07027

 

Parameter Correlation:

	Parent_O	K_Parent
Parent_O	1	0.8327
K_Parent	0.8327	1

 

Observed v. Predicted:

Time (Days)	Value (% of Dose)	Predicted Value	Residual
0	94.9	96.55	-1.652
32	96.8	96.4	0.4019
61	97.8	96.26	1.541
91	96.1	96.11	-0.07463
120	96.7	95.98	0.7244
152	96.2	95.82	0.3776
182	94.3	95.68	-1.379

 

Table 12. Disappearance of DBDPEthane from Soil 2

Interval (Days)	Soil Extracts
	%	ug/kg
0 32 61 91 120 152 182	93.5 94.1 95.7 95.4 94.7 95.7 95.1	1693 1703 1733 1726 1714 1733 1721

 

Table 13. Regression Analysis of DBDPEthane in Soil 2 Extracts: Simple First-Order Model Statistics

Estimated Values:

Parameter	Value	Sigma	Prob.>t	Lower CI	Upper CI
Parent_O	94.89	0.628	1.205E-10	93.27	96.5
K_Parent	5.77E-14	6.054E-05	0.5	00.0001556	0

 

Chi-Squared:

Parameter	Error %	Degrees of Freedom
All data	1.005	5
Parent	1.005	5

 

Decay Times:

Compartment	DT50 (Days)	DT90 (Days)
Parent	1.2E+13	3.988E+13

 

Additional Statistics:

Parameter	r2 (Obs. v. Pred.)	Efficiency
All data	0.418	0.418
Parent	0.418	0.418

 

Parameter Correlation:

	Parent_O	K_Parent
Parent_O	1	0.8337
K_Parent	0.8337	1

 

Observed v. Predicted:

Time (Days)	Value (% of Dose)	Predicted Value	Residual
0	93.5	94.89	-1.386
32	94.1	94.89	-0.7857
61	95.7	94.89	0.8142
91	95.4	94.89	0.5142
120	94.7	94.89	-0.1858
152	95.7	94.89	0.8141
182	95.1	94.89	0.2141

 

Table 14. Disappearance of DBDPEthane from Soil 3

Interval (Days)	Soil Extracts
	%	ug/kg
0 32 61 91 120 152 182	93.6 94.9 95.9 95.4 94.0 94.4 95.4	1695 1717 1736 1727 1702 1709 1727

 

 

Table 15. Regression Analysis of DBDPEthane in Soil 3 Extracts: Simple First-Order Model Statistics

Estimated Values:

Parameter	Value	Sigma	Prob.>t	Lower CI	Upper CI
Parent_O	94.8	0.6259	1.19E-10	93.19	96.4
K_Parent	5.494E-12	6.039E-05	0.5	-0.0001552	0

 

Chi-Squared:

Parameter	Error %	Degrees of Freedom
All data	1.005	5
Parent	1.005	5

 

Decay Times:

Compartment	DT50 (Days)	DT90 (Days)
Parent	1.262E+11	4.191E+11

 

Additional Statistics:

Parameter	r2 (Obs. v. Pred.)	Efficiency
All data	0.05605	0.05605
Parent	0.05605	0.05605

 

Parameter Correlation:

	Parent_O	K_Parent
Parent_O	1	0.8337
K_Parent	0.8337	1

 

Observed v. Predicted:

Time (Days)	Value (% of Dose)	Predicted Value	Residual
0	93.6	94.8	-1.2
32	94.9	94.8	0.09997
61	95.9	94.8	1.1
91	95.4	94.8	0.5999
120	94	94.8	-0.8001
152	94.4	94.8	-0.4001
182	95.4	94.8	0.5998

 

Table 16. Disappearance of DBDPEthane from Soil 4

Interval (Days)	Soil Extracts
	%	ug/kg
0 32 61 91 120 152 182	93.9 95.1 95.1 96.5 94.6 93.7 94.2	1699 1721 1722 1747 1713 1695 1705

 

 

Table 17. Regression Analysis of DBDPEthane in Soil 4 Extracts: Simple First-Order Model Statistics

Estimated Values:

Parameter	Value	Sigma	Prob.>t	Lower CI	Upper CI
Parent_O	94.99	0.7022	2.095E-10	93.18	96.8
K_Parent	2.973E-05	6.774E-05	0.3395	-0.0001444	0

 

Chi-Squared:

Parameter	Error %	Degrees of Freedom
All data	1.005	5
Parent	1.005	5

 

Decay Times:

Compartment	DT50 (Days)	DT90 (Days)
Parent	2.332E+04	7.745E+04

 

Additional Statistics:

Parameter	r2 (Obs. v. Pred.)	Efficiency
All data	0.03729	0.03729
Parent	0.03729	0.03729

 

Parameter Correlation:

	Parent_O	K_Parent
Parent_O	1	0.8331
K_Parent	0.8331	1

 

Observed v. Predicted:

Time (Days)	Value (% of Dose)	Predicted Value	Residual
0	93.9	94.99	-1.085
32	95.1	94.9	0.2048
61	95.1	94.81	0.2866
91	96.5	94.73	1.771
120	94.6	94.65	-0.0473
152	93.7	94.56	-0.8573
182	94.2	94.47	-0.2731

 

Conclusions:

DBDPEthane did not appear to degrade in any of the four soils. The mean percentage of radioactivity recovered as DBDPEthane at the end of the 6-month test was >94% in all soil extracts. There was no clear pattern of decline, and the half-lives were extrapolated well beyond the 6-month test period. The DT50 values were >6 months for all four soils.

Executive summary:

This study was conducted to assess the potential mineralization and transformation of DBDPEthane in aerobic soil systems. Four types of soil were utilized in the study. Soils were dosed with 14C-ring labeled DBDPEthane at a nominal concentration of 1.8 mg/kg dry soil. Test systems were incubated at approximately 20 ºC for up to 182 days, and maintained under aerobic conditions by purging the headspace in each vessel with air. Effluent gases were passed through ethylene glycol to trap organic volatiles, followed by alkali solutions to trap evolved carbon dioxide. Duplicate test chambers of each soil type were sacrificed on days 0, 32, 61, 91, 120, 152 and 182. Soil extracts and soil solids were analyzed separately for total radioactivity by liquid scintillation counting (LSC). Soil extracts were analyzed by HPLC for parent test substance and other radio-labeled products. DBDPEthane did not appear to degrade in any of the four soils. The mean percentage of radioactivity recovered as DBDPEthane at the end of the 6-month test was >94% in all soil extracts. There was no clear pattern of decline, and the half-lives were extrapolated well beyond the 6-month test period. The DT50 values were >6 months for all four soils.

Reference 2

Endpoint:

biodegradation in soil: simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

August 12, 2013 - January 23, 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 307 (Aerobic and Anaerobic Transformation in Soil)

GLP compliance:

yes

Test type:

laboratory

Specific details on test material used for the study:

14C-ring-labeled DBDPEthane

Radiolabelling:

yes

Remarks:

14C- ring-labeled

Oxygen conditions:

anaerobic

Soil classification:

other:

Year:

2013

Soil no.:

#1

Soil type:

loamy sand

% Clay:

9

% Silt:

9

% Sand:

82

% Org. C:

0.94

pH:

5.2

CEC:

10.2 meq/100 g soil d.w.

Bulk density (g/cm³):

1.16

Soil no.:

#2

Soil type:

sandy clay loam

% Clay:

21

% Silt:

13

% Sand:

66

% Org. C:

1.9

pH:

6.9

CEC:

17.9 meq/100 g soil d.w.

Bulk density (g/cm³):

1.04

Soil no.:

#3

Soil type:

clay loam

% Clay:

29

% Silt:

27

% Sand:

44

% Org. C:

4

pH:

5.4

CEC:

31.4 meq/100 g soil d.w.

Bulk density (g/cm³):

0.99

Soil no.:

#4

Soil type:

sandy clay loam

% Clay:

29

% Silt:

23

% Sand:

48

% Org. C:

2.8

pH:

7.9

CEC:

68.8 meq/100 g soil d.w.

Bulk density (g/cm³):

1.01

Soil No.:

#1

Duration:

6 mo

Soil No.:

#2

Duration:

6 mo

Soil No.:

#3

Duration:

6 mo

Soil No.:

#4

Duration:

6 mo

Soil No.:

#1

Initial conc.:

1.5 mg/kg soil d.w.

Soil No.:

#2

Initial conc.:

1.5 mg/kg soil d.w.

Soil No.:

#3

Initial conc.:

1.5 mg/kg soil d.w.

Soil No.:

#4

Initial conc.:

1.5 mg/kg soil d.w.

Parameter followed for biodegradation estimation:

radiochem. meas.

Soil No.:

#1

Temp.:

20C

Microbial biomass:

211.7 ug/g

Soil No.:

#2

Temp.:

20C

Microbial biomass:

543.2 ug/g

Soil No.:

#3

Temp.:

20C

Microbial biomass:

531.5 ug/g

Soil No.:

#4

Temp.:

20C

Microbial biomass:

548.3 ug/g

Details on experimental conditions:

This study was conducted to assess the potential mineralization and transformation of DBDPEthane
in anaerobic soil systems. Four types of soil were utilized in the study. Soils were dosed with 14C-ring
labeled DBDPEthane at a nominal concentration of 1.5 mg/kg dry soil. Test systems were incubated at
approximately 20 ºC for up to 182 days. Aerobic conditions were maintained for the first 32 days by
purging the headspace in each vessel with air. Effluent gases were passed through ethylene glycol to trap
organic volatiles, followed by alkali solutions to trap evolved carbon dioxide. On day 32, the soils were
flooded, purged with nitrogen, and sealed to maintain anaerobic conditions. Duplicate test chambers of
each soil type were sacrificed on months 0, 1, 2, 3, 4, 5 and 6. The water layers, soil extracts and soil
solids were analyzed separately for total radioactivity by liquid scintillation counting (LSC).

Soil No.:

#1

% Recovery:

96.4

Soil No.:

#2

% Recovery:

95.3

Soil No.:

#3

% Recovery:

95.3

Soil No.:

#4

% Recovery:

93.5

Key result

Soil No.:

#1

% Degr.:

2.1

Parameter:

radiochem. meas.

Sampling time:

6 mo

Key result

Soil No.:

#2

% Degr.:

3.8

Parameter:

radiochem. meas.

Sampling time:

6 mo

Key result

Soil No.:

#3

% Degr.:

4.2

Parameter:

radiochem. meas.

Sampling time:

6 mo

Key result

Soil No.:

#4

% Degr.:

3.4

Parameter:

radiochem. meas.

Sampling time:

6 mo

Key result

Soil No.:

#1

DT50:

> 6 mo

Type:

(pseudo-)first order (= half-life)

Temp.:

20 °C

Key result

Soil No.:

#2

DT50:

> 6 mo

Type:

(pseudo-)first order (= half-life)

Temp.:

20 °C

Key result

Soil No.:

#3

DT50:

> 6 mo

Type:

(pseudo-)first order (= half-life)

Temp.:

20 °C

Key result

Soil No.:

#4

DT50:

> 6 mo

Type:

(pseudo-)first order (= half-life)

Temp.:

20 °C

Transformation products:

no

Remarks:

There were no distinct, consistent tramsformation product peaks observed during the study.

Material Balance Results

A summary of the distribution of 14C in the various fractions and material balance results is

presented in Table 7. The table contains the mean results from both test vessels of each soil type sacrificed at each sampling interval. The mean material balances ranged from 90.7% to 107.9% throughout the test, and were considered acceptable.

 

Transformation Results in Soils

Soils were collected and extracted on days 0, 32, 62, 92, 120, 152 and 182. The total amount of

radioactivity in each soil sample was calculated as the sum of the amounts measured in the overlying

water layers, MeOH soil extracts, THF soil extracts, plus the amounts measured in the soil solids after

extraction. Extraction efficiencies were calculated as the proportion of radioactivity in the extracts versus the total radioactivity in the soil sample. A summary of the extraction efficiencies is presented in

Table 8. The table contains the mean results from both test vessels of each soil type sacrificed at each

sampling interval. Mean extraction efficiencies ranged from 96.8% to 99.0% on day 0. Extraction

efficiencies remained relatively constant, and were ≥95% throughout the study. On day 182, mean

extraction efficiencies for transformation test vessels ranged from 95.7% to 98.0.

 

The overlying water layers contained ≤0.2% of the radioactivity at any sampling interval; therefore,

no further work was performed on the water layer samples.

 

The MeOH and THF soil extracts were combined and concentrated, prior to extraction with

chloroform. The combined, concentrated soil extracts were partitioned three times with chloroform to

remove endogenous matrix materials that might interfere with chromatographic analyses. A summary of the chloroform extraction results is presented in Table 9. The table contains the mean results from both test vessels of each soil type sacrificed at each sampling interval. Mean recoveries for the chloroform extraction procedure ranged from 92.2% to 130%. The proportion of 14C in the CHCl3 extracts was >95%, with the following three exceptions. The aqueous fraction from soil 3 on day 92 (test vessel 40) contained 17.8% of the 14C, the aqueous fraction from soil 4 on day 92 (test vessel 55) contained 8.2%, and the aqueous fraction from soil 1 on day 182 (test vessel 14) contained 7.7%. In each case, an emulsion formed causing some of the chloroform to remain suspended in the aqueous fraction. The chloroform extracts were concentrated prior to HPLC analyses. A summary of the procedural recoveries during soil extract processing is presented in Table 10. The table contains the mean results from both test vessels of each soil type sacrificed at each sampling interval. With the exception of two samples that were partially spilled, the overall procedural recoveries were >93%.

 

The concentrated chloroform extracts were analyzed using HPLC/-RAM to determine the relative

distributions of parent test substance and other 14C products. In addition, aqueous fractions that

contained >1% of the 14C were analyzed using HPLC/-RAM. The integration results from each sample were divided into three regions of interest (ROIs), as described previously in the “HPLC/β-RAM Analyses” section of this report. A summary of the HPLC results is presented in Table 11. The table contains the mean results from both test vessels of each soil type sacrificed at each sampling interval. The mean amounts of 14C remaining in the overlying water layers plus the aqueous fractions after chloroform partitioning are presented as a region named “Aqueous Sample”. Aqueous fractions that contained >1% of the 14C were analyzed by HPLC and results were included in the ROIs, rather than the “Aqueous Sample”. The mean amount of parent DBDPEthane in the soil extracts on day 0 ranged from 91.5% to 95.1%. At the end of the test, the mean amount of DBDPEthane ranged from 93.5% to 96.4%. Further discussions of the results can be found in the sections for each soil.

 

Supplemental Extractions

At the end of the test, the amount of radioactivity remaining in/on the soil solids after extractions

was ≤5% for all samples. Supplemental extractions were not conducted and no further

analytical work was performed on the soil solids.

 

Results from Soil 1

The mean material balance results from soil 1 are presented in Table 7. Material balance results from individual test vessels ranged from 96.3% to 108.5% throughout the test. On day 0, the mean percent of dosed radioactivity in the soil extracts was 103.4%, and 1.1% was bound to the soil solids. At the end of the test, the mean amount in the soil extracts was 100.5%, and 2.1% was bound to the soil solids. During the study, the mean soil extraction efficiency was 98.0% for all 16 samples. The mean cumulative amount of 14C gas production over the 6-month test period was 0.08% (Table 6).

 

The mean distributions of [14C]DBDPEthane and other products in the soil extracts are presented in

Table 11. The mean amount of parent (DBDPEthane) was 95.1% on day 0 and 96.4% on day

182. The mean amounts and concentrations of DBDPEthane are presented in Table 12. The means were

used in regression analyses in an attempt to determine disappearance rates for DBDPEthane, and did not include the 14C bound to the soil solids. The results from a simple first-order (SFO) decay curve model are presented in Table 13.. The SFO model did not fit the data well (r2 <0.70), but none of the other models were a better fit. The amount of DBDPEthane in the soil extracts never dropped below 92%, so the DT50 was >6 months. The mean total amount of other products was 3.9% on day 0, and was the maximum amount observed at any interval for Soil 1. The amount of impurities in the test substance was 5.5%. The other product peaks observed in the soil extracts were attributed to impurities, rather than transformation products. None of the individual peaks accounted for >2.0% of the dose.

No further attempts were made to identify the other products.

 

Results from Soil 2

The mean material balance results from soil 2 are presented in Table 7. Material balance results from individual test vessels ranged from 91.1% to 106.9% throughout the test. On day 0, the mean percent of dosed radioactivity in the soil extracts was 89.1%, and 2.6% was bound to the soil solids. At the end of the test, the mean amount in the soil extracts was 96.2%, and 3.8% was bound to the soil solids. During the study, the mean soil extraction efficiency was 96.3% for all 16 samples. The mean cumulative amount of 14C gas production over the 6-month test period was 0.09% (Table 6).

 

The mean distributions of [14C]DBDPEthane and other products in the soil extracts are presented in

Table 11. The mean amount of parent (DBDPEthane) was 92.0% on day 0 and 95.3% on day

182. The mean amounts and concentrations of DBDPEthane are presented in Table 14. The means were

used in regression analyses in an attempt to determine disappearance rates for DBDPEthane, and did not include the 14C bound to the soil solids. The results from a simple first-order (SFO) decay curve model are presented in Table 15. The SFO model did not fit the data well (r2 <0.70), but none of the other models were a better fit. The amount of DBDPEthane in the soil extracts never dropped below 90%, so the DT50 was >6 months. The mean total amount of other products was 5.2% on day 0, and was the maximum amount observed at any interval for soil 2. The amount of impurities in the test substance was 5.5%. The other product peaks observed in the soil extracts were attributed to impurities, rather than transformation products. None of the individual peaks accounted for >3.2% of the dose.

 No further attempts were made to identify the other products.

 

Results from Soil 3

The mean material balance results from soil 3 are presented in Table 7. Material balance results from individual test vessels ranged from 91.3% to 107.3% throughout the test. On day 0, the mean percent of dosed radioactivity in the soil extracts was 92.5%, and 2.6% was bound to the soil solids. At the end of the test, the mean amount in the soil extracts was 93.8%, and 4.2% was bound to the soil solids. During the study, the mean soil extraction efficiency was 96.1% for all 16 samples. The mean cumulative amount of 14C gas production over the 6-month test period was 0.09% (Table 6).

 

The mean distributions of [14C]DBDPEthane and other products in the soil extracts are presented in

Table 11. The mean amount of parent (DBDPEthane) was 91.5% on day 0 and 95.3% on day 182. The

mean amounts and concentrations of DBDPEthane are presented in Table 16. The means were used in

regression analyses in an attempt to determine disappearance rates for DBDPEthane, and did not include the 14C bound to the soil solids. The results from a simple first-order (SFO) decay curve model are presented in Table 17. The SFO model did not fit the data well (r2 <0.70), but none of the other models were a better fit. The amount of DBDPEthane in the soil extracts never dropped below 89%, so the DT50 was >6 months.

 

The mean total amount of other products was 5.8% on day 0, and was the maximum amount

observed at any interval for soil 3. The amount of impurities in the test substance was 5.5%. The other

product peaks observed in the soil extracts were attributed to impurities, rather than transformation

products. None of the individual peaks accounted for >2.2% of the dose. No further attempts were made to identify the other products.

 

Results from Soil 4

The mean material balance results from soil 4 are presented in Table 7. Material balance results from individual test vessels ranged from 89.7% to 101.1% throughout the test (Appendix XV). On day 0, the mean percent of dosed radioactivity in the soil extracts was 90.0%, and 2.9% was bound to the soil solids. At the end of the test, the mean amount in the soil extracts was 87.3%, and 3.4% was bound to the soil solids. During the study, the mean soil extraction efficiency was 96.5% for all 16 samples. The mean cumulative amount of 14C gas production over the 6-month test period was 0.08% (Table 6).

 

The mean distributions of [14C]DBDPEthane and other products in the soil extracts are presented in

Table 11. The mean amount of parent (DBDPEthane) was 94.6% on day 0 and 93.5% on day 182. The mean amounts and concentrations of DBDPEthane are presented in Table 18. The means were used in regression analyses in an attempt to determine disappearance rates for DBDPEthane, and did not include the 14C bound to the soil solids. The results from a simple first-order (SFO) decay curve model are presented in Table 19. The SFO model did not fit the data well (r2 <0.70), but none of the other models were a better fit. The amount of DBDPEthane in the soil extracts never dropped below 91%, so the DT50 was >6 months.

 

The mean total amount of other products was 2.2% on day 0, and reached a maximum of 3.1% on

day 92. The amount of impurities in the test substance was 5.5%. The other product peaks observed in

the soil extracts were attributed to impurities, rather than transformation products. None of the individual peaks accounted for >2.0% of the dose. No further attempts were made to identify the other products.

Table 3. Woil RedOx Potentials

Interval (Study Day)	Date	Soil 1	Soil 2	Soil 3	Soil 4
32 33 34 35 39 46 53 62 71 82 92 109 120 137 152 167 182	October 14, 2013 October 15, 2013 October 16, 2013 October 17, 2013 October 21, 2013 October 28, 2013 November 4, 2013 November 13, 2013 November 22, 2013 December 3, 2013 December 13, 2013 December 30, 2013 January 10, 2014 January 27, 2014 February 11, 2014 February 26, 2014 March 13, 2014	537 506 501 492 -11 -95 -144 -183 -178 -172 -182 -190 -185 -211 -218 -225 -215	445 307 263 1 -154 -274 -253 -262 -262 -235 -233 -239 -247 -255 -254 -252 -253	419 449 468 453 161 -79 -140 -197 -239 -233 -231 -227 -225 -212 -193 -198 -217	436 209 214 137 -197 -268 -278 -280 -278 -271 -266 -260 -258 -253 -254 -258 -258

Redox potential of soil layer (Eh)

Table 4. Viability Assessment Results

Test Start (Study Day)	Interval (Study Day)	Soil 1 (%)	Soil 2 (%)	Soil 3 (%)	Soil 4 (%)
62	7 14 21 28	26.7 803 -- --	23.3 41.6 52.9 --	17.5 37.6 53.3 --	18.1 44.1 52.6 --
182	7 14 21 28	51.2 67.7 -- --	23.0 38.5 46.8 56.1	25.7 47.0 55.8 --	29.7 47.0 52.4 --

Results given in cumulative % of applied 14C recovered in gas traps

Table 5. Mean Cumulative Radioactivity in All Transformation Vessel Gas Traps

Test Soil	Interval (Days)	Volatile 14C Gases (%)	Evolved 14CO2 (%)	Total Gases (%)
Soil 1	32 62 92 120 152 182	0.00 0.01 0.01 0.01 0.01 0.01	0.00 0.01 0.02 0.01 0.01 0.01	0.00 0.03 0.03 0.02 0.01 0.01
Soil 2	32 62 92 120 152 182	0.00 0.00 0.01 0.01 0.01 0.01	0.00 0.01 0.02 0.01 0.01 0.00	0.00 0.02 0.02 0.02 0.01 0.01
Soil 3	32 62 92 120 152 182	0.00 0.00 0.01 0.01 0.01 0.00	0.00 0.01 0.00 0.02 0.01 0.01	0.00 0.02 0.01 0.03 0.02 0.01
Soil 4	32 62 92 120 152 182	0.00 0.01 0.01 0.01 0.01 0.00	0.00 0.01 0.02 0.01 0.01 0.01	0.00 0.02 0.02 0.02 0.01 0.01

 

 

 

Table 6. Mean Cumulative Radioactivity in All Mineralization Vessel Gas Traps

Test Soil	Interval (Days)	Evolved 14CO2 (%)	Volatile 14C Gases (%)	Total Gases (%)
Soil 1	32 61 91 120 152 182	0.00 0.01 0.02 0.03 0.03 0.04	0.00 0.01 0.02 0.03 0.03 0.04	0.00 0.02 0.04 0.05 0.07 0.08
Soil 2	32 61 91 120 152 182	0.00 0.01 0.02 0.03 0.03 0.04	0.00 0.01 0.02 0.03 0.04 0.05	0.00 0.02 0.04 0.05 0.07 0.09
Soil 3	32 61 91 120 152 182	0.00 0.01 0.02 0.03 0.03 0.04	0.00 0.01 0.02 0.03 0.04 0.05	0.00 0.02 0.04 0.06 0.07 0.09
Soil 4	32 61 91 120 152 182	0.00 0.01 0.02 0.03 0.03 0.04	0.00 0.01 0.02 0.03 0.04 0.04	0.00 0.02 0.04 0.05 0.07 0.08

 

 

 

 

Table 7. Mean Distribution of Radioactivity from Test Vessels

Test Soil	Interval (Days)	Water Layers (%)	Combined Sediment Extracts (%)	Combusted Soil Solids (%)	Total Gases (%)	Material Balance (Recovery %)
Soil 1             Mineral	0 32 61 91 120 152 182 182	NA 0.1 0.0 0.0 0.0 0.0 0.0 0.0	103.4 105.8 99.3 98.6 96.3 95.1 100.5 95.8	1.1 2.0 1.6 2.0 2.4 2.6 2.1 2.2	NA 0.0 0.0 0.0 0.0 0.0 0.0 0.1	104.5 107.9 100.9 100.7 98.7 97.7 102.6 98.1
Soil 2             Mineral	0 32 61 91 120 152 182 182	NA 0.0 0.0 0.0 0.0 0.0 0.0 0.0	89.1 102.1 94.8 89.8 96.6 93.2 96.2 92.1	2.6 3.5 3.3 3.6 4.0 4.1 3.8 3.8	NA 0.0 0.0 0.0 0.0 0.0 0.0 0.1	91.6 105.6 98.1 93.4 100.6 97.4 100.1 96.0
Soil 3             Mineral	0 32 61 91 120 152 182 182	NA 0.0 0.0 0.0 0.1 0.0 0.0 0.0	95.5 96.5 92.6 91.1 94.3 95.7 93.8 90.1	2.6 3.1 3.7 3.5 4.9 4.0 4.2 3.9	NA 0.0 0.0 0.0 0.0 0.0 0.0 0.1	95.0 99.6 96.4 94.7 99.3 99.8 98.1 94.2
Soil 4             Mineral	0 32 61 91 120 152 182 182	NA 0.0 0.0 0.0 0.0 0.0 0.0 0.0	90.0 96.7 93.6 91.9 89.3 93.4 87.3 89.8	2.9 2.8 2.9 3.2 4.4 3.6 3.4 3.4	NA 0.0 0.0 0.0 0.0 0.0 0.0 0.1	92.9 99.5 96.5 95.1 93.7 97.0 90.7 93.3

NA – Not Applicable

 

Table 8. Mean Soil Extraction Efficiencies

Test Soil	Interval (Days)	Mean DPM in Comb. Soil Extracts	Mean DPM in Soil Solids	Mean DPM in Soil Sample	Proportion In/on Solids (%)	Mean Extraction Efficiency (%)
Soil 1             Mineral	0 32 61 91 120 152 182 182	11786796 12071011 11324398 11198084 11004845 10811351 11434600 10867271	124314 224071 187487 232648 275033 297287 234082 250257	11911110 12303936 11512417 11433067 11281371 11109089 11669706 11118931	1.0 1.8 1.6 2.0 2.4 2.7 2.0 2.3	99.0 98.1 98.4 97.9 97.5 97.3 98.0 97.7
Soil 2             Mineral	0 32 61 91 120 152 182 182	10151650 11668153 10810553 10220103 10973690 10681752 10928808 10512733	291997 398488 373237 405301 452779 474774 437067 437228	10443647 12066798 11184097 10625651 11426921 11156997 11366287 10950744	2.8 3.3 3.3 3.8 4.0 4.3 3.8 4.0	97.2 96.7 96.7 96.2 96.0 95.7 96.2 96.0
Soil 3             Mineral	0 32 61 91 120 152 182 182	10591991 11020261 10591810 10429650 10763792 10935012 10673887 10251547	294400 352709 426868 399692 560761 458662 480219 446977	10886391 11373066 11019301 10833878 11333084 11395004 11156101 10700515	2.7 3.1 3.9 3.7 4.9 4.0 4.3 4.2	97.3 96.9 96.1 96.3 95.0 96.0 95.7 95.8
Soil 4             Mineral	0 32 61 91 120 152 182 182	10217138 11092015 10633424 10510338 10215858 10678878 9984150 10268187	344917 318824 333863 364494 499320 415058 385401 388785	10552056 11411008 10967542 10874851 10715408 11094264 10370095 10657436	3.2 2.8 3.0 3.4 4.7 3.7 3.7 3.6	96.8 97.2 97.0 96.6 95.3 96.3 96.3 96.3

 

Table 9. Mean Chloroform Extraction Results

Test Soil	Interval (Days)	Mean DPM in Conc. Soil Extracts	Mean DPM in Chloroform Extracts	Mean DPM in Aqueous Fractions	Recovery %	% in Aqueous Fractions	Mean Extraction Efficiency (%)
Soil 1             Mineral	0 32 61 91 120 152 182 182	11764818 10699181 10035853 10138838 9994961 10100748 9959962 10386560	11847724 10543665 10593007 10508927 10504496 10144895 9406999 10107760	4986 126115 4834 11543 5545 12121 431910 94291	100.8 99.7 105.6 103.7 105.2 100.6 99.0 98.2	0.0 1.2 0.0 0.1 0.1 0.1 4.2 0.9	100.0 98.8 100.0 99.9 99.9 99.9 95.8 99.1
Soil 2             Mineral	0 32 61 91 120 152 182 182	8480418 10273270 10244022 8891377 10314738 10061562 10217082 10114832	8332737 10514367 10202407 9624253 10404598 10303730 10108471 10052771	18947 4215 2255 11442 216771 5394 1896 18049	98.2 102.5 99.7 108.5 103.4 102.4 99.0 99.6	0.3 0.0 0.0 0.1 2.0 0.1 0.0 0.2	97.7 100.0 100.0 99.9 98.0 99.9 100.0 99.8
Soil 3             Mineral	0 32 61 91 120 152 182 182	10512618 9817289 9917273 9740174 10248083 9067497 9401930 9745450	9624067 9986942 10194283 8581573 10155211 9948605 9520535 9113277	73345 4726 7566 835771 163574 25039 71716 194462	92.2 101.8 102.9 96.8 100.6 110.2 102.1 95.5	0.8 0.0 0.1 8.9 1.6 0.2 0.8 2.1	99.2 100.0 99.9 91.1 98.4 99.8 99.2 97.9
Soil 4             Mineral	0 32 61 91 120 152 182 182	10075209 7723379 10006780 10251688 10047018 9401960 9449130 9761775	9873335 10020570 10013533 9385400 9617600 9674928 8987129 9425953	7696 2626 25200 432080 249270 113639 236817 216560	98.1 129.9 100.4 95.7 98.2 105.0 97.6 98.8	0.1 0.0 0.3 4.3 2.5 1.3 2.6 2.2	99.9 100.0 99.7 95.7 97.5 98.7 97.4 97.8

 

Table 10. Mean Procedural Recoveries

Test Soil	Interval (Days)	Mean Recovery Combined Soil Extract Concentration (%)	Mean Recovery Chloroform Extraction (%)	Mean Recovery Chloroform Extract Concentration	Overall Mean Extraction Efficiency (%)
Soil 1             Mineral	0 32 61 91 120 152 182 182	105.3 93.9 93.6 94.6 94.5 100.3 94.6 101.5	100.8 99.7 105.6 103.7 105.2 100.6 99.0 98.2	95.0 99.4 102.9 100.8 106.1 107.1 107.9 106.6	100.8 93.1 101.5 98.8 105.4 108.0 101.0 106.3
Soil 2             Mineral	0 32 61 91 120 152 182 182	90.6 92.9 98.8 90.1 97.4 100.2 101.5 101.8	98.2 102.5 99.7 108.5 103.4 102.4 99.0 99.6	102.5 102.6 96.5 105.4 105.0 102.2 105.0 107.2	91.1 97.6 95.0 102.9 105.5 104.9 105.4 108.7
Soil 3             Mineral	0 32 61 91 120 152 182 182	105.3 94.0 97.5 97.8 99.5 88.9 95.0 104.1	92.2 101.8 102.9 96.8 100.6 110.2 102.1 95.5	112.1 107.6 103.6 105.6 104.7 106.4 104.9 104.9	109.0 102.9 103.9 99.8 104.7 103.9 101.7 104.3
Soil 4             Mineral	0 32 61 91 120 152 182 182	104.0 74.0 98.1 101.9 101.8 94.0 100.5 103.7	98.1 129.9 100.4 95.7 98.2 105.0 97.6 98.8	107.4 107.5 102.8 106.1 102.8 101.9 104.6 103.7	109.6 103.2 101.2 103.4 102.8 100.3 102.6 106.3

 

 

 

 

 

 

 

Table 11. Mean Distribution of Parent and Other ¹⁴C Products in Soil Extracts

Test Soil	Interval (Days)	Aqueous Fraction (%)	Before (1.0-11.3) (%)	Parent (11.3-12.3) (%)	After (12.3-16.0) (%)	Total % of Sample	Total % Other 14C Products
Soil 1             Mineral	0 32 61 91 120 152 182 182	0.1 0.1 0.1 0.1 0.1 0.2 0.4 0.9	2.1 1.6 0.6 0.2 0.3 0.7 0.9 0.2	95.2 95.4 95.8 97.3 96.3 93.9 96.4 96.4	1.6 1.1 1.8 0.3 0.9 2.7 0.3 0.2	99.0 98.2 98.4 98.0 97.6 97.4 98.0 97.7	3.8 2.8 2.5 0.6 1.2 3.5 1.6 1.3
Soil 2             Mineral	0 32 61 91 120 152 182 182	0.3 0.0 0.0 0.1 0.1 0.1 0.0 0.2	0.3 0.4 0.0 1.1 0.3 1.6 0.5 0.0	92.0 91.8 95.8 94.0 94.9 93.4 95.3 95.5	4.6 4.5 0.9 1.1 0.8 0.7 0.3 0.3	97.2 96.7 96.6 96.2 96.1 95.7 96.1 96.0	5.2 4.8 0.9 2.2 1.2 2.3 0.8 0.5
Soil 3             Mineral	0 32 61 91 120 152 182 182	0.2 0.1 0.1 0.1 0.5 0.3 0.1 0.0	2.9 0.2 1.4 1.0 0.7 1.1 0.2 0.7	91.5 95.9 93.3 92.1 92.8 92.7 95.3 95.1	2.6 0.8 1.3 3.0 1.1 1.9 0.1 0.0	97.3 96.9 96.2 96.2 95.1 96.0 95.6 95.8	5.8 1.0 2.8 4.1 2.3 3.2 0.4 0.7
Soil 4             Mineral	0 32 61 91 120 152 182 182	0.1 0.0 0.3 0.3 0.0 0.1 0.2 0.0	0.8 0.7 0.3 1.3 0.2 0.8 0.3 1.5	94.8 94.7 95.9 93.5 93.7 95.2 93.5 93.6	1.1 1.8 0.5 1.6 1.4 0.1 2.4 1.3	96.8 97.1 97.0 96.7 95.3 96.3 96.3 96.4	2.0 2.5 1.0 3.1 1.6 1.0 2.8 2.8

 

 

 

Table 12. Disappearance of DBDPEthane from Soil 1

Interval (Days)	Soil Extracts
	Mean %	ug/kg
0 32 61 91 120 152 182	95.2 95.4 95.8 97.3 96.3 93.9 96.4	1.47 1.47 1.48 1.50 1.48 1.45 1.49

 

Table 13. Regression Analysis of DBDPEthane in Soil 1 Extracts: Simple First-Order Statistics

Estimated Values:

Parameter	Value	Sigma	Prob.>t	Lower CI	Upper CI
Parent_O	95.76	0.811	4.133E-10	93.67	97.84
K_Parent	1.427E-19	7.733E-05	0.5	-0.0001988	0

 

 

 

Chi-Squared:

Parameter	Error %	Degrees of Freedom
All data	1.005	5
Parent	1.005	5

 

Decay Times:

Compartment	DT50 (Days)	DT90 (Days)
Parent	4.858E+18	1.614E+19

 

Additional Statistics:

Parameter	r2 (Obs. v. Pred.)	Efficiency
All data	0.006144	9.055E-06
Parent	0.006144	9.055E-06

 

Parameter Correlation:

	Parent_O	K_Parent
Parent_O	1	0.8348
K_Parent	0.8348	1

 

 

  

Observed v. Predicted:

Time (Days)	Value (% of Dose)	Predicted Value	Residual
0	95.2	95.76	-0.5571
32	95.4	95.76	-0.3572
61	95.8	95.76	0.0428
91	97.3	95.76	1.543
120	96.3	95.76	0.5427
152	93.9	95.76	-1.857
182	96.4	95.76	0.6427

 

 

Table 14. Disappearance of DBDPEthane from Soil 2

Interval (Days)	Soil Extracts
	Mean %	ug/kg
0 32 61 91 120 152 182	92.0 91.8 95.8 94.0 94.9 93.4 95.3	1.42 1.41 1.48 1.45 1.46 1.44 1.47

 

 

 

 

 

Table 15. Regression Analysis of DBDPEthane in Soil 2 Extracts: Simple First-Order Statistics

Estimated Values:

Parameter	Value	Sigma	Prob.>t	Lower CI	Upper CI
Parent_O	93.89	1.183	3.011E-09	90.84	96.93
K_Parent	2.741E-16	0.0001151	0.5	-0.0002958	0

 

Chi-Squared:

Parameter	Error %	Degrees of Freedom
All data	1.223	5
Parent	1.223	5

 

Decay Times:

Compartment	DT50 (Days)	DT90 (Days)
Parent	2.528E+15	8.4E+15

 

Additional Statistics:

Parameter	r2 (Obs. v. Pred.)	Efficiency
All data	0.3579	4.65E-05
Parent	0.3579	4.65E-05

 

Parameter Correlation:

	Parent_O	K_Parent
Parent_O	1	0.8348
K_Parent	0.8348	1

 

Observed v. Predicted:

Time (Days)	Value (% of Dose)	Predicted Value	Residual
0	92	93.89	-1.8862
32	91.8	93.89	-2.086
61	95.8	93.89	1.914
91	94	93.89	0.1142
120	94.9	93.89	1.014
152	93.4	93.89	-0.4859
182	95.3	93.89	1.414

 

 

Table 16. Disappearance of DBDPEthane from Soil 3

Interval (Days)	Soil Extracts
	Mean %	ug/kg
0 32 61 91 120 152 182	91.5 95.9 93.3 92.1 92.8 92.7 95.3	1.41 1.48 1.44 1.42 1.43 1.43 1.47

 

  

Table 17. Regression Analysis of DBDPEthane in Soil 3 Extracts: Simple First-Order Statistics

Estimated Values:

Parameter	Value	Sigma	Prob.>t	Lower CI	Upper CI
Parent_O	93.37	1.229	3.73E-09	90.21	96.53
K_Parent	2.055E-12	0.0001202	0.5	-0.0003089	0

 

Chi-Squared:

Parameter	Error %	Degrees of Freedom
All data	1.29	5
Parent	1.29	5

 

Decay Times:

Compartment	DT50 (Days)	DT90 (Days)
Parent	3.37E+11	1.121E+12

 

Additional Statistics:

Parameter	r2 (Obs. v. Pred.)	Efficiency
All data	0.04802	1.63E-05
Parent	0.04802	1.63E-05

 

Parameter Correlation:

	Parent_O	K_Parent
Parent_O	1	0.8348
K_Parent	0.8348	1

 

Observed v. Predicted:

Time (Days)	Value (% of Dose)	Predicted Value	Residual
0	91.5	93.37	-1.871
32	95.9	93.37	2.529
61	93.3	93.37	-0.07149
91	92.1	93.37	-1.272
120	92.8	93.37	-0.5715
152	92.7	93.37	-0.6716
182	95.3	93.37	1.928

 

Table 18. Disappearance of DBDPEthane from Soil 4

Interval (Days)	Soil Extracts
	Mean %	ug/kg
0 32 61 91 120 152 182	94.8 94.7 95.9 93.5 93.7 95.2 93.5	1.46 1.46 1.48 1.44 1.44 1.47 1.44

  

 

Table 19. Regression Analysis of DBDPEthane in Soil 3 Extracts: Simple First-Order Statistics

Estimated Values:

Parameter	Value	Sigma	Prob.>t	Lower CI	Upper CI
Parent_O	95.02	0.6385	1.3E-10	93.38	96.66
K_Parent	6.325E-05	6.158E-05	0.1757	-9.504E-05	0

 

Chi-Squared:

Parameter	Error %	Degrees of Freedom
All data	1.005	5
Parent	1.005	5

 

Decay Times:

Compartment	DT50 (Days)	DT90 (Days)
Parent	1.096E+04	3.641E+04

 

Additional Statistics:

Parameter	r2 (Obs. v. Pred.)	Efficiency
All data	0.1743	0.1743
Parent	0.1743	0.1743

 

Parameter Correlation:

	Parent_O	K_Parent
Parent_O	1	0.8335
K_Parent	0.8335	1

Observed v. Predicted:

Time (Days)	Value (% of Dose)	Predicted Value	Residual
0	94.8	95.02	-0.2186
32	94.7	94.83	-0.1265
61	95.9	94.65	1.253
91	93.5	94.47	-0.9674
120	93.7	94.3	-0.6003
152	95.2	94.11	1.09
182	93.5	93.93	-0.4313

 

 

Conclusions:

DBDPEthane did not appear to degrade in any of the four anaerobic soils. The mean percentage of radioactivity recovered as DBDPEthane at the end of the 6-month test was >93% in all soil extracts. The DT50 values were >6 months for all four soils.

Executive summary:

This study was conducted to assess the potential mineralization and transformation of DBDPEthane in anaerobic soil systems. Four types of soil were utilized in the study. Soils were dosed with 14C-ring labeled DBDPEthane at a nominal concentration of 1.5 mg/kg dry soil. Test systems were incubated at approximately 20 ºC for up to 182 days. Aerobic conditions were maintained for the first 32 days by purging the headspace in each vessel with air. Effluent gases were passed through ethylene glycol to trap organic volatiles, followed by alkali solutions to trap evolved carbon dioxide. On day 32, the soils were flooded, purged with nitrogen, and sealed to maintain anaerobic conditions. Duplicate test chambers of each soil type were sacrificed on months 0, 1, 2, 3, 4, 5 and 6. The water layers, soil extracts and soil solids were analyzed separately for total radioactivity by liquid scintillation counting (LSC).

DBDPEthane did not appear to degrade in any of the four anaerobic soils. The mean percentage of radioactivity recovered as DBDPEthane at the end of the 6-month test was >93% in all soil extracts. There was no clear pattern of decline, and the half-lives were extrapolated well beyond the 6-month test period. The DT50 values were >6 months for all four soils. Through all test intervals, the mean maximum percentages of radioactivity recovered as other products were 3.9%, 5.2%, 5.8% and 3.1% for soils 1, 2, 3 and 4, respectively. The amount of impurities in the test substance applied to the soils was 5.5%, based on the certificate of analysis. The other products observed in the soil extracts were attributed to impurities in the test substance, rather than transformation products. There were no distinct, consistent transformation product peaks observed during the study. The mean fractions of radiolabeled residues that could not be extracted from soils 1, 2, 3 and 4 at the end of the test were 2.1%, 3.8%, 4.2% and 3.4%, respectively. The maximum cumulative amount of mineralization or ultimate biodegradation observed was <0.1% is all four soils. Mean material balances (recoveries) ranged from 90.7% to 107.9% throughout the study.

Reference 3

Endpoint:

biodegradation in soil, other

Type of information:

experimental study

Adequacy of study:

key study

Study period:

June - October 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guidline/GLP-compliant study performed by an experienced laboratory

Qualifier:

according to guideline

Guideline:

other: OECD 302 D, Proposed, Inherent Biodegradability

Principles of method if other than guideline:

Pre-exposed soil/activated sludge were addied to mineral test media and incubated under aerobic conditions for 90 d. Hexadecane served as the positive control. Replicate chambers were analyzed at intervals during the test for inorganic carbon and 14C-parent and metabolites. Conditions were optimized in favor of biodegradation.

GLP compliance:

yes

Test type:

laboratory

Specific details on test material used for the study:

The test substance was received from Albemarle Corporation on November 28, 2007 and was
assigned Wildlife International, Ltd. identification number 8303. The following is a description of
the test substance used in this study:
Identity: Saytex® 8010
Lot Number: S17009C
Physical Description: Solid
Purity: 97.6%
Expiration Date: November 26, 2012
Storage Conditions: Room temperature in a closed container
Carbon Content: 17.30%
The test substance was administered to the treatment group test chambers by direct weight
addition. Direct weight addition is an appropriate route of administration for poorly water-soluble
materials. The amount of test substance used to dose the treatment group test chambers, was
calculated based on the carbon content. The carbon content of the test substance was determined
based on the molecular weight and chemical formula of the test substance.
The radiolabeled form of the test substance was received from Perkin Elmer on February 23,
2010 and was assigned Wildlife International, Ltd. identification number 9412. The following is a
description of the radiolabeled test substance used in this study:
Name: 1,2-Bis[pentabromophenyl]ethane, [Phenyl-14C[U]]
Lot number: 3626190
Formula weight: 972
Specific activity: 32.4 mCi/mmol, (33.3 μCi/mg)
Radiochemical purity: 94.5%
Sample form: solid

Radiolabelling:

yes

Oxygen conditions:

aerobic

Soil classification:

not specified

Year:

2010

Details on soil characteristics:

Soil was collected from Claiborne, MD and used the same day of collection. Activated sludge was collected from the Cambridge Wastewater Treatment Facility, Cambridge, MD, which treats predominantly residential wastes. The sludge was seved using a 2-mm screan and aerated until use.

Soil No.:

#1

Duration:

> 0 - < 90 d

Soil No.:

#2

Duration:

> 0 - < 90 d

Soil No.:

#1

Initial conc.:

20 other: mg C/L

Soil No.:

#2

Initial conc.:

70 other: ug/L

Parameter followed for biodegradation estimation:

radiochem. meas.

Soil No.:

#1

Temp.:

19.5 - 22.3 degrees C

Details on experimental conditions:

The aerobic inocula were pre-exposed to DBDP-Ethane prior to use. For each group, soil (1.0 g), activated sludge (2 ml) and yeast extract (50 mg) were added to test medium (1 L). The pH was adjusted to 7.4 ± 0.2, and DBDP-Ethane added at concentrations equivalent to 4, 8, and 8 mg C/L on days 0, 7 and 11, respectively. The contents were mixed with a magnetic stirrer and allowed gaseous exchange with a foam stopper for the duration of the pre-exposure. On day 14, the inoculum was screened (filter paper) and aerated overnight to reduce the organic carbon content. On the day of use, the inoculum was sparged with CO2-free air for 1 hour, and the dissolved organic (DOC) and inorganic (DIC) levels measured.

Key result

Soil No.:

#1

% Degr.:

0

Parameter:

inorg. C analysis

Sampling time:

90 d

Remarks on result:

not determinable

Key result

Soil No.:

#2

% Degr.:

0

Parameter:

radiochem. meas.

Sampling time:

90 d

Remarks on result:

not determinable

Key result

Soil No.:

#1

DT50:

> 90 d

Temp.:

20 °C

Remarks on result:

other: not calculated

Key result

Soil No.:

#2

DT50:

> 90 d

Temp.:

20 °C

Remarks on result:

other: not calculated

Transformation products:

no

Details on transformation products:

There were no transformation products.

Evaporation of parent compound:

no

Volatile metabolites:

no

Details on results:

Table 1. Inherent aerobic biodegradation results of decabromodiphenyl ethane (DBDP-Ethane) and hexadecane as the test and reference substances, respectively, expressed as inorganic carbon (IC) and percent of theoretical inorganic carbon (TIC) evolved (Mean ± Standard deviation; n=3 chambers/group D 14-73; n = 5 chambers/group D90).

Day IC (mg C/L) % TIC Evolved
Blank Hexadecane DBDP-Ethane Blank Hexadecane DBDP-Ethane
14 1.0 ± 0.1 16.3 ± 0.9 1.2 ± 0.1 NA 76.5 ± 4.4 1.2 ± 0.4
28 1.2 ± 0.4 19.2 ± 1.9 0.9 ± 0.1 NA 90.2 ± 9.6 -1.6 ± 0.5
42 1.6 ± 0.4 22.9 ± 1.9 2.4 ± 0.6 NA 106.3 ± 9.8 4.3 ± 3.1
56 1.9 ± 0.3 23.1 ± 2.0 2.3 ± 0.4 NA 106.1 ± 10.1 2.3 ± 1.9
73 2.6 ± 0.2 23.1 ± 1.8 3.2 ± 0.3 NA 103.1 ± 9.2 3.1 ± 1.4
90 2.9 ± 1.2 23.0 ± 1.9 3.4 ± 0.9 NA 100.1 ± 9.3 2.2 ± 4.5
Overall Mean* 1.9 ± 0.8 21.3 ± 2.9 2.2 ± 1.0 NA 97.0 ± 11.7 1.9 ± 2.0
NA=not applicable.
*Calculated from means.

Results with reference substance:

see results

The test met the validity criteria specified in the guideline. The mean percentage biodegradation of hexadecane was ≥60% ThIC and was reached by Day 14, indicating the inoculum was viable and performed as expected. Further, the mean amount of IC produced by the blank controls at the end of the test was ≤15% of the organic carbon added initially as DBDP-Ethane to the test bottles.  

The mean evolved IC from the hexadecane reference group was substantially greater than either the untreated control or the DBDP-Ethane treatment group on all days while the mean evolved IC in the DBDP-Ethane group was similar to that of the untreated control (Table 1). While bottles treated with hexadecane evolved a mean of 97.0 % ThIC over the study, ThIC evolved from the DBDP-Ethane bottles was similar to the blank controls. Substances are considered to lack inherent biodegradation when <= 20% ThIC is evolved.  

The entire contents of the test chamber were extracted and analyzed for¹⁴C-activity. No indication of degradation of [¹⁴C]DBDP-Ethane was observed on HPLC/β-RAM analysis. One peak containing the radiolabel was detected. That peak had a retention time consistent with the parent molecule.

Conclusions:

Not inherently biodegradable under optimized conditions over a 90 d period.

Executive summary:

Inherent biodegradation of DBDP-Ethane by a mixture of pre-exposed sludge and soil bacteria over a 90-day period was not observed. Two methods were used to investigate biodegradation: ThIC and¹⁴C-analysis for the parent molecule and metabolites. Because inherent biodegradation tests are designed to assess whether a chemical has any potential for biodegradaton (OECD, 2006), the observed results suggest DBDP-Ethane is unlikely to undergo aerobic biodegradation in the environment or in sewage treatment plants. 

Description of key information

EBP: AEROBIC TRANSFORMATION IN SOIL (Wildlife, 2015), OECD 307 

 This study was conducted to assess the potential mineralization and transformation of DBDPEthane in aerobic soil systems. Four types of soil were utilized in the study. Soils were dosed with 14C-ring labeled DBDPEthane at a nominal concentration of 1.8 mg/kg dry soil. Test systems were incubated at approximately 20 ºC for up to 182 days, and maintained under aerobic conditions by purging the headspace in each vessel with air. Effluent gases were passed through ethylene glycol to trap organic volatiles, followed by alkali solutions to trap evolved carbon dioxide. Duplicate test chambers of each soil type were sacrificed on days 0, 32, 61, 91, 120, 152 and 182. Soil extracts and soil solids were analyzed separately for total radioactivity by liquid scintillation counting (LSC). Soil extracts were analyzed by HPLC for parent test substance and other radio-labeled products. DBDPEthane did not appear to degrade in any of the four soils. The mean percentage of radioactivity recovered as DBDPEthane at the end of the 6-month test was >94% in all soil extracts. There was no clear pattern of decline, and the half-lives were extrapolated well beyond the 6-month test period. The DT50 values were >6 months for all four soils.

EBP: Anaerobic transformation in soil (Wildlife, 2015), OECD 307 

DBDPEthane did not appear to degrade in any of the four anaerobic soils. The mean percentage of radioactivity recovered as DBDPEthane at the end of the 6-month test was >93% in all soil extracts. The DT50 values were >6 months for all four soils.

 EBP degradation in a soil-plant system (note this study is summarized in section 5.6. of IUCLID as it could not be included technically into 5.2.3)

 ​[14C] EBP was dosed to the soil test pots via inactivated sludge carrier and incubated for up to 60-61 days with or without growing plants in a greenhouse. The study consists of 3 experiments including 4 types of soils and 6 plant species staggered in 3 separate experiments. Day 1 and Day 60-61 sacrificial soil and plant samples were sequentially extracted with toluene and further cleaned-up and concentrated. The sample processing procedures were able to quantitatively recover 14C from soil and plant samples. 14C radioactivity analysis by LSC indicates that dosed [14C] EBP and Br9 as an impurity moved to the roots of rye grass plants, and to a much less extent to the roots of other plants species (e.g., radish, alfalfa, zucchini, corn, and pumpkin plants). No root to shoot movement of 14C was observed for all 6 plant species. HPLC/β-RAM analysis demonstrated that [14C] EBP was thepredominant analyte in soil and root samples. LC/MS targeted analysis of soil samples observed [14C] EBP, Br9 and Br9-II but no Br6-Br8 were detected. The levels of Br9 and Br9-II observed in all soil samples from three experiments were either lower or statistically the same as those observed in corresponding dose stock solution or dose mixture used for the test, indicating that [14C] EBP was not biodegraded. LC/MS targeted analysis of root samples observed [14C] EBP in all 6 plant species but only detected Br9 above LOQ level (10 μg/L) in ryegrass and corn plants. No Br6-Br8 and Br-9 II were detected in root samples of all 6 plant species. This suggests that Br9 and [14C] EBP may not be further unique isotope cluster patterns of Br6-Br10 ([14C] EBP) confirmed that [14C] EBP) was not biodegraded to form novel metabolites with structures related to Br6-Br10 ([14C] EBP). 

The experimental evidence from this study via targeted and non-targeted LC/MS analyses indicates that no [14C] EBP biodegradation occurred in soil and plant samples during 60-61 days of incubation.