Orthosulfamuron

Biodegradation in water and sediment: simulation tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: sediment simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 308 (Aerobic and Anaerobic Transformation in Aquatic Sediment Systems)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: SETAC, Part 1, Section 8.2 “Aerobic aquatic degradation”, March 1995

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

[14C-5-pyrimidinyl]IR5878 Lot 208
Specific radioactivity: 267117 dpm/µg
120.323 µCi/mg
4.452 MBq/mg
Radiochemical purity: > 97%


Unlabelled IR5878
Batch number: 20698/27
Purity: > 97%

Radiolabelling:

yes

Inoculum or test system:

natural water / sediment: freshwater

Details on source and properties of surface water:

The degradation of 14C-IR5878 has been studied in two aquatic systems, named Pond system and River system, over a 155 days period.

Details on source and properties of sediment:

The degradation of 14C-IR5878 has been studied in two aquatic systems, named Pond system and River system, over a 155 days period.

Initial conc.:

>= 75 other: g/ha

Key result

Compartment:

natural water: freshwater

DT50:

>= 10 d

Temp.:

20 °C

Remarks on result:

other: Pond and River

Key result

Compartment:

natural sediment: freshwater

DT50:

>= 41 d

Temp.:

20 °C

Remarks on result:

other: Pond

Key result

Compartment:

natural sediment: freshwater

DT50:

>= 24 d

Temp.:

20 °C

Remarks on result:

other: River

Key result

Compartment:

natural water / sediment: freshwater

DT50:

>= 27 d

Temp.:

20 °C

Remarks on result:

other: Pond

Key result

Compartment:

natural water / sediment: freshwater

DT50:

>= 20 d

Temp.:

20 °C

Remarks on result:

other: River

Transformation products:

yes

Details on transformation products:

The metabolite S12 (IR7825) reached a maximum of 77.10 % AR in the river system. No other compounds were found to exceed 10% AR.

Findings

The radioactivity in the surface water decreased from 99.22% of the applied radioactivity (AR) to 7.94% AR (pond system) and from 99.53% AR to 19.88% AR (river system).

The radioactivity in sediment (extractable + bound) increased from 19.22% AR to 93.21% AR (pond system) and from 15.43% AR to 69.76% AR (river system).

The radioactivity in the pond sediment extracts increased to a maximum of 70.71% AR at 91 days, then it decreased to 63.89% AR at 155 days. The radioactivity in the river sediment extracts increased to 62.17% AR at 91 days, then it decreased to 54.27% AR at 155 days.

¹⁴C-IR5878 degraded in both water-sediment systems, and its amount accounted for 2.44% AR and 0.77% AR respectively in the pond system and in the river system at the last sampling time.

DT_50laband DT_90labvalues (Disappearance Time for 50% and 90% of the starting concentration) are summarised in Table 7.8-8.

 

Table 7.8-8     DT_50laband DT_90labvalues for IR5878

	DT50lab		DT90lab		r^2
	Pond	River	Pond	River	Pond	River
Surface water	10 days	10 days	33 days	32 days	0.902	0.939
Sediment	41 days	24 days	136 days	80 days	0.926	0.862
Whole system	27 days	20 days	91 days	66 days	0.902	0.953

 

Seven compounds were found in the surface water and in the sediment extracts: unchanged¹⁴C-IR5878 and six degradation compounds.

The main degradation compounds were S12 and the fraction S11: S12 reached amounts higher than 60% AR, the fraction S11 was constituted by a pool of 6-10 compounds, none of which reached amounts higher than 5% AR. The other minor degradation compounds (S9, S13, S15, S16) never reached amounts higher than 10% AR.

 

Table 7.8-9     Radioactivity distribution of¹⁴C-IR5878 and its main degradation compounds in surface water

Time point	Pond system (Compounds % AR)			River system (Compounds % AR)
(days)	S3 (IR5878)	S11	S12	S3 (IR5878)	S11	S12
0	94.43	< dl	2.68	93.48	0.60	2.82
3	68.11	0.76	5.81	72.58	0.60	4.27
7	56.17	2.83	6.48	60.62	1.23	5.06
15	36.54	8.51	5.33	42.03	4.40	6.31
31	23.95	7.62	7.70	27.43	10.38	6.81
45	2.68	3.52	15.36	4.81	6.95	27.32
60	< dl	4.16	8.90	0.87	5.42	26.60
91	< dl	2.90	6.01	< dl	7.49	22.39
120	0.46	2.71	3.44	< dl	1.86	14.08
155	0.42	1.77	3.04	< dl	1.68	14.21

dl = detection limit = 0.39% AR and 0.40% AR only for 45 days

 

Table 7.8-10   Radioactivity distribution of¹⁴C-IR5878 and its main degradation compounds in sediment

Time point	Pond system (Compounds % AR)			River system (Compounds % AR)
(days)	S3 (IR5878)	S11	S12	S3 (IR5878)	S11	S12
0	nd	nd	nd	nd	nd	nd
3	11.39	<dl	3.32	12.84	< dl	2.07
7	12.62	0.27	7.05	22.08	0.40	4.58
15	15.74	2.29	8.91	22.98	2.49	8.68
31	18.69	3.95	16.15	24.44	5.51	11.93
45	12.47	2.79	41.65	25.66	5.85	14.09
60	6.13	2.91	51.22	4.79	3.32	50.51
91	4.33	2.72	56.77	2.60	2.77	51.70
120	3.27	1.99	53.69	1.16	2.13	49.28
155	2.02	2.44	53.99	0.77	1.49	47.91

nd = Not determined

dl = detection limit = 0.13% AR

 

Table 7.8-11   Radioactivity distribution of¹⁴C-IR5878 and its main degradation compounds in whole system

Time point	Pond system (Compounds % AR)			River system (Compounds % AR)
(days)	S3 (IR5878)	S11	S12	S3 (IR5878)	S11	S12
0	94.43	< dl	2.68	93.48	0.60	2.82
3	79.50	0.76	9.14	85.42	0.60	6.34
7	68.79	3.10	13.53	82.70	1.63	9.64
15	52.28	10.80	14.25	65.01	6.89	14.99
31	42.64	11.57	23.85	51.87	15.89	18.74
45	15.14	6.31	57.01	30.46	12.79	41.41
60	6.13	7.08	60.12	5.65	8.74	77.10
91	4.33	5.62	62.78	2.60	10.26	74.08
120	3.73	5.00	57.14	1.16	3.99	63.36
155	2.44	4.21	57.03	0.77	3.17	62.12

 

The non-extractable radioactivity (bound residue) increased to 29.32% AR and to 15.49% AR in pond and river system, respectively.

The fractionation of organic matter was carried on the samples when the bound residue was higher than 20%. In pond system samples incubated 155 days humin fraction accounted for 19.49% AR, fulvic acid fraction for 6.48% AR and humic acid fraction for 2.38% AR.

The radioactivity in the¹⁴C-CO₂traps was lower than the detection limit in both the systems till 31 days, then it was detected at amounts ranging from 1.31% AR and 1.98% AR in pond system and from 0.10% AR to 1.01% AR in river system.

The Mass Balance was always higher than 95% AR in the pond system, where it ranged from 95.00% AR to 103.36% AR and it was always higher than 90% AR in the river system, where it ranged from 90.65% AR to 103.70% AR.

 

Table 7.8-12   ¹⁴C-Mass Balance

Time point (days)	Pond system				River system
	Surface water	Sediment	CO2	Total	Surface water	Sediment	CO2	Total
0	99.22	-	na	99.22	99.53	<dl	na	99.53
3	78.27	19.22	<dl	97.49	80.61	15.43	<dl	96.04
7	69.30	26.74	<dl	96.04	71.11	29.65	<dl	100.76
15	56.81	44.88	<dl	101.69	59.15	40.25	<dl	99.40
31	44.36	55.62	<dl	99.98	49.63	46.85	<dl	96.48
45	24.24	76.60	1.35	102.19	43.53	55.22	0.85	99.60
60	16.29	83.10	1.34	100.73	36.53	67.07	0.10	103.70
91	12.83	89.22	1.31	103.36	30.59	68.45	0.77	99.81
120	9.52	83.50	1.98	95.00	21.92	69.24	0.86	92.02
155	7.94	93.21	1.54	102.69	19.88	69.76	1.01	90.65

Validity criteria fulfilled:

yes

Conclusions:

The degradation of [14C-5-pyrimidinyl]IR5878 has been studied in two aquatic systems over a 155 days period.
Several degradation products were separated, and S12 (IR7825) exceeded 10% AR.
DT50lab were 10 days for surface water in both pond and river system.
DT50lab were 41 and 24 days for sediment in pond and river system respectively.
DT50lab were 27 and 20 days for whole system in pond and river system respectively.

Executive summary:

The degradation of [¹⁴C-5-pyrimidinyl]IR5878 has been studied in two aquatic systems, named Pond system and River system, over a 155 days period.

Several degradation products were separated, and S12 (IR7825) exceeded 10% AR. DT_50labwere 10 days for surface water in both pond and river system. DT_50labwere 41 and 24 days for sediment in pond and river system, respectively. DT_50labwere 27 and 20 days for whole system in pond and river system, respectively.

Description of key information

The degradation of [¹⁴C-5-pyrimidinyl]IR5878 has been studied in two aquatic systems, named Pond system and River system, over a 155 days period.

Several degradation products were separated, and S12 (IR7825) exceeded 10% AR. DT_50labwere 10 days for surface water in both pond and river system. DT_50labwere 41 and 24 days for sediment in pond and river system, respectively. DT_50labwere 27 and 20 days for whole system in pond and river system, respectively.

Key value for chemical safety assessment

Half-life in freshwater:

10 d

at the temperature of:

20 °C

Half-life in freshwater sediment:

41 d

at the temperature of:

20 °C