2-ethylhexyl (4-chloro-2-methylphenoxy)acetate

Biodegradation in water and sediment: simulation tests

Administrative data

Endpoint:

biodegradation in water and sediment: simulation testing, other

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24.05.2005 - 25.06.2005

Reliability:

1 (reliable without restriction)

Cross-reference

Reason / purpose for cross-reference:

read-across source

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

(4-chloro-2-methylphenoxy)acetic acid

EC Number:

202-360-6

EC Name:

(4-chloro-2-methylphenoxy)acetic acid

Cas Number:

94-74-6

Molecular formula:

C9H9ClO3

IUPAC Name:

(4-chloro-2-methylphenoxy)acetic acid

impurity 1

Reference substance name:

Water

EC Number:

231-791-2

EC Name:

Water

Cas Number:

7732-18-5

Molecular formula:

H2O

IUPAC Name:

water

impurity 2

Reference substance name:

4-chloro-o-cresol

EC Number:

216-381-3

EC Name:

4-chloro-o-cresol

Cas Number:

1570-64-5

Molecular formula:

C7H7ClO

IUPAC Name:

4-chloro-2-methylphenol

Test material form:

solid

Radiolabelling:

no

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

natural water / sediment

Details on source and properties of sediment:

Two kinds of sediments including their associated water with determined physical and chemical parameters, taken from aerobic zone to a maximum depth of 10 cm in the experiment were used. On the basis of the texture analysis the used sediments were classified as a fine texture sediment (I) and coarse texture sediment (II).
The first aquatic sediment was taken from silty bottom of Mlynowka river, located in Pszczyna (49 ° 58' and 9.49W; 18 ° 54' and 41.49"E), while the second sediment was taken from sandy stone bottom, covered by aqueous plants of littoral zone of Goczalkowickie Lake, located in Pszczyna - Lqka (49 ° 56' and 43.63W; 18 ° 54' and 31.69"E). The sampling places were not contaminated by test material (MCPA) and other substances from group of phenoxyacetic acids.

Results and discussion

Half-life of parent compound / 50% disappearance time (DT50)

Key result

Compartment:

natural water / sediment

DT50:

<= 27 d

Type:

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

Temp.:

20 °C

Remarks on result:

other: Temperature of measurement was 18-22 oC

Transformation products:

yes

Remarks:

4-chloro-2-methylphenol CAS# 1570-64-5

Identity of transformation products

No.:

#1

Reference

Reference substance name:

Unnamed

IUPAC name:

4-chloro-2-methylphenol

Inventory number:

InventoryMultipleMappingImpl [inventoryEntryValue=EC 216-381-3]

CAS number:

1570-64-5

Identity:

4-chloro-o-cresol

Identity:

Phenol, 4-chloro-2-methyl-

Molecular formula:

C7H7ClO

Molecular weight:

142.583

SMILES notation:

Cc1cc(Cl)ccc1O

InChl:

InChI=1/C7H7ClO/c1-5-4-6(8)2-3-7(5)9/h2-4,9H,1H3

Any other information on results incl. tables

The concentrations of MCPA in aquatic sediments samples obtained during the experiment are presented as follows:

Table 1. MCPA TECHNICAL - aerobic transformation in aquatic sediments concentration of MCPA in system I: water -fine texture sediment

Day of test/ date	Concentration in sediment [mg/kg]				Concentration in water mg/kgJ*				Total concentration in sediment and water [mg/kg]	Percent of the initial concentration [%]	Decrease in relation to the initial concentration [%]
	replicate		Average	RSD Nd	replicate		Average	RSD
	I	II			I	II
0 24.10.2005	0.65	0.68	0.66	2.26	9.09	9.42	9.25	2.58	9.91	100	0.0
2 26.10.2005	1.54	1.57	1.56	1.55	7.72	8.11	7.91	3.53	9.47	95.6	4.4
4 28.10.2005	2.38	2.43	2.41	1.29	6.17	5.88	6.02	3.40	8.43	85.1	14.9
6 30.10.2005	0.58	0.56	0.57	2.82	7.51	7.64	7.58	1.15	8.15	82.2	17.8
9 2.11.2005	0.59	0.60	0.60	1.33	7.27	6.93	7.10	3.34	7.70	77.7	22.3
12 5.11.2005	0.34	0.28	0.31	13.45	7.19	7.50	7.35	3.00	7.66	77.3	22.7
16 9.11.2005	0.83	0.81	0.82	1.73	6.53	6.27	6.40	2.88	7.22	72.9	27.1
20 13.11.2005	0.13	0.15	0.14	9.42	6.42	6.60	6.51	1.97	6.65	67.1	32.9
32 25.11.2005	2.50	2.65	2.57	4.20	1.98	2.02	2.00	1.31	4.57	46.1	53.9
48 11.12.2005	0.57	0.57	0.57	0.88	<0.04	<0.04	<0.04	-	0.57	5.8	94.2

* it was accepted that 1000 ml of water weighs 1 kg

 

Table 2. MCPA TECHNICAL - aerobic transformation in aquatic sediments concentration of MCPA in system II: water -fine texture sediment

Day of test/ date	Concentration in sediment [mg/kg]				Concentration in water mg/kg]*				Total concentration in sediment and water [mg/kg]	Percent of the initial concentration [%]	Decrease in relation to the initial concentration [%]
	replicate		Average	RSD Nd	replicate		Average	RSD [NI
	I	II			I	II
0 24.10.2005	0.91	0.86	0.89	3.52	8.08	8.45	8.27	3.16	9.16	100	0.0
2 26.10.2005	1.43	1.46	1.45	1.36	7.25	7.40	7.33	1.52	8.78	95.9	4.1
4 28.10.2005	1.19	1.21	1.20	1.22	6.61	6.64	6.62	0.30	7.82	85.4	14.6
6 30.10.2005	0.45	0.45	0,45	0.63	7.63	7.38	7.50	2.36	7.95	86.8	13.2
9 2.11.2005	0.52	0.48	0.50	5.03	7.03	7.07	7.05	0.39	7.55	82.4	17.6
12 5.11.2005	<0.07	<0.07	<0.07	-	7.12	6.83	6.97	2.93	6.97	76.1	23.9
16 9.11.2005	0.07	<0.07	0.07	9.26	6.50	6.25	6.37	2.71	6.44	70.3	29.7
20 13.11.2005	<0.07	<0.07	<0.07	10.45	6.01	6.03	6.02	0.29	6.02	65.7	34.3
32 25.11.2005	1.20	0.83	1.01	26.13	2.19	2.22	2.20	1.09	3.21	35.0	65.0
48 11.12.2005	0.73	0.78	0.75	4.83	<0.04	<0.04	<0.04	-	0.75	8.2	91.8

* it was accepted that 1000 ml of water weighs 1 kg

The concentrations of 4-chloro-2-methylphenol in aquatic sediments samples obtained during the experiment are presented in Tables:

 

Table 3 MCPA TECHNICAL - aerobic transformation in aquatic sediments concentration of 4-chloro-2-methylphenol in system I: water -fine texture sediment

Day of test/ date	Concentration in sediment [mg/kg]				Concentration in water [mg/kg]*				Total concentration in sediment and water [mg/kg]
	replicate		Average	RSD	replicate		Average	RSD
	I	II			I	H
0 24.10.2005	0.08	0.08	0.08	-	<0.02	<0.02	<0.02	-
2 26.10.2005	0.22	0.20	0.21	6.78	<0.02	<0.02	<0.02	-	-
4 28.10.2005	<0.03	<0.03	<0.03	-	<0.02	<0.02	<0.02	-	-
6 30.10.2005	0.20	0.21	0.21	2.10	<0.02	<0.02	<0.02	-	-
9 2.11.2005	0.10	0.12	0.11	15.83	<0.02	<0.02	<0.02	-	-
12 5.11.2005	0.09	0.09	0.09	0.09	<0.02	<0.02	<0.02	-	-
16 9.11.2005	0.31	0.29	0.30	4.15	<0.02	<002	<0.02	-	-
20 13.11.2005	0.13	0.13	0.13	0.48	<0.02	<0.02	<0.02	-	-
32 25.11.2005	0.42	0.36	0.39	9.89	<0.02	<0.02	<0.02	-	-
48 11.12.2005	0.45	0.49	0.47	6.09	<0.02	<0.02	<0.02	-	-

 

 

Table 4 MCPA TECHNICAL - aerobic transformation in aquatic sediments concentration of 4-chloro-2-methylphenol in system II: water -coarse texture sediment

Day of test' date	Concentration in sediment [mg/kg]				Concentration in water [mg/kg]*				Total concentration in sediment and water [mg/kg]
	replicate		Average	RSD	replicate		Average	RSD
	I	II			I	H
0 24.10.2005	<0.03	<0.03	<0.03	-	<0.02	<0.02	<0.02	-
2 26.10.2005	<0.03	<0.03	<0.03	-	<0.02	<0.02	<0.02	-	-
4 28.10.2005	<0.03	<0.03	<0.03	-	<0.02	<0.02	<0.02	-	-
6 30.10.2005	<0.03	<0.03	<0.03	-	<0.02	<0.02	<0.02	-	-
9 2.11.2005	<0.03	<0.03	<0.03	-	<0.02	<0.02	<0.02	-	-
12 5.11.2005	<0.03	<0.03	<0.03	-	<0.02	<0.02	<0.02	-	-
16 9.11.2005	0.09	0.10	0.09	10.1	<0.02	<0.02	<0.02	-	-
20 13.11.2005	<0.03	<0.03	<0.03	-	<0.02	<0.02	<0.02	-	-
32 25.11.2005	<0.03	<0.03	<0.03	-	<0.02	<0.02	<0.02	-	-
48 11.12.2005	<0.03	<0.03	< 0.03	-	<0.02	<0.02	<0.02	-	-

 

Taking into account the obtained results it was assessed that MCPA TECHNICAL was degraded, and the DT50 is 26.6 and 25.8 days for aquatic sediment I (fine texture) and aquatic sediment II (coarse texture), respectively.

Detailed time disappearance of MCPA (DT75 and DT90) in tested aquatic sediments are presented in Table 5.

 

Table 5 MCPA TECHNICAL - aerobic transformation in aquatic sediments disappearance time for MCPA

DTx	Time of disappearance [days]
	System I water —fine texture sediment	System II water — coarse texture sediment
DT50	26.6	25.8
DT75	40.6	39.1
DT90	48.9	47.1

 

 The DT50, DT75 and DT90 values were calculated from equation of the degradation curve. During the experiment of aerobic transformation it was assessed a little amount of 4-chloro-2-methylphenol in water and sediments.

Applicant's summary and conclusion

Conclusions:

Taking into account the obtained results it was assessed that degradation of MCPA TECHNICAL in aerobic conditions did not depend on kind of sediment, used in the experiment. However, DT50 values for MCPA in both sediments did not exceed 27 days.

Executive summary:

The aim of the study was to determine DT50, DT75 and DT90 values, which are the time within which the concentration of a test material is reduced by 50%, 75%, 90% respectively (w/w).

Two kinds of sediments including their associated water with determined physical and chemical parameters, taken from aerobic zone to a maximum depth of 10 cm in the experiment were used. On the basis of the texture analysis the used sediments were classified as a fine texture sediment (I) and coarse texture sediment (II).

The flow-through system equipped with vessels closed with rubber cork, containing the suitable amount of sediment and volume of water (1:3) as a test system in the experiment was used. The aerobic conditions were maintained by continuously ventilating with humidified air.

The test material, in a form of acetonitrile : water solution (1:200), was introduced into the water phase in volume of 10 ml, obtained the final concentration equal to 10 mg / l.

The test duration was 48 days. After 0, 2, 4, 6, 9, 12, 16, 20, 32, 48 days of incubation two samples of each sediment including their water were removed from the test system and extracted with suitable solvents and analyzed to determine the concentration of the test material (MCPA) and their major transformation product (4-chloro-2-methylphenol). Chemical analysis was performed with liquid-liquid extraction method and the final analysis was performed by using the liquid chromatograph with UV-VIS detector.

Taking into account the obtained results it was assessed that MCPA was degraded in aerobic conditions, and the DT50 value is 26.6 and 25.8 days for aquatic sediment I ( fine texture) and aquatic sediment II ( coarse texture), respectively.

During aerobic transformation study, a little amount of 4-chloro2-methylphenol were recorded.