Ethanone, 1-(4-methoxyphenyl)-2-[(3-methoxyphenyl)thio]-

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

June 2006 to Feb 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

469-300-0

EC Name:

-

Cas Number:

63675-73-0

Molecular formula:

Hill Empirical Formula: C16H16O3S CAS Empirical Formula: C16H16O3S

IUPAC Name:

1-(4-methoxyphenyl)-2-[(3-methoxyphenyl)sulfanyl]ethan-1-one

Test material form:

solid: particulate/powder

Details on test material:

Lot no: 151105Purity - 101.39%

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Daphnia magna were exposed to the nominal concentrations in a static-renewal system for 48 hours with a renewal of test media at 24 hours.At 0 and 24 hours, nominal 10 and 100mg/l test media were prepared by direct addition fo Beta Ketosulfide to daphnia dilution water (ASTM) with acetone as a solvent carrier (100uL/L).The 100mg/l test medium was filtered (0.45um filter), to prepare the nominal 2.60mg/l test medium (the practical solubility limit of the compound). The remaining test media were prepared by serial d ilution fo the 2.60mg/l. Acetone was added to each serially diluted test media to ensure equivalent solvent loading rates (0.1mL/L) in all treatments. Two controls: Solvent (ASTM + 0.1mL/L acetone) and an ASTM only control, were also prepared.Four test vessels were prepared for each treatment (including the control treatment), each containing 100 ml of test medium and five juvenile (<24 hours old). D. magna animals were observed at 24 and 48 hours for immobilitsation and were not fed for the duration of the test,Samples for analysis were taken at 0 and 24 hours from new test media and at 24 and 48 hours from pooled replicate samples of old test media. Daphnia were transferred into fresh media following observations each day for the duration of the test.

Test solutions

Vehicle:

yes

Remarks:

Acetone

Details on test solutions:

The dilution water used was ASTM. The definitive test was conducted at nominal exposure concentrations of 0.10, 0.22,0.50, 1.20, 2.60, 10 and 100 mg/L as Beta Ketosulfide.New test media at 10 mg/L were prepared at 0 and 24 hours by direct addition of 9.95 and 10.04 mg of Beta Ketosulfide, respectively, to glass weigh boats. Acetone (100 µL) was added to each weighing. The acetone solution was then rinsed into a 1 litre volumetric flask and made up to volume with ASTM water.New test media at 100 mg/L were prepared at 0 and 24 hours by direct addition of 200.02 and 200.07 mg of Beta Ketosulfide (respectively) to glass weigh boats. Acetone (200 µL} was added to each weighing. The acetone solution was then rinsed into a 2 litre volumetric flask and made up to volume with ASTM water.The flask contents at 0 and 24 hours, were pre-treated with 30 minutes ultrasound treatment and stirred in the dark for approximately 1 hour.After stirring, the nominal 2.60 mg/L test medium (practical solubility limit for this test) was prepared by filtering I 000 ml of the I 00 mg/L test medium through a 0.45 µm filter. The remaining test media were prepared by serial dilution the 2.60 mg!L test medium. Aliquots of acetone were added to each serially diluted test media to ensure equivalent solvent loading rates (0.1 mUL) in all treatments.Two controls; a solvent (ASTM water+ 0.1 mUL acetone) control and an ASTM only control, were also prepared.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Juvenile Daplmia magna (Straus), less than 24 hours old, were taken from parental cultures (aged 32 days) held and maintained at Covance Laboratories Ltd. The culture was originally obtained from The Environment Agency, Portsmouth.

Study design

Test type:

semi-static

Water media type:

other: ASTM Standard hard water

Limit test:

yes

Total exposure duration:

48 h

Remarks on exposure duration:

At 24 hours, in the nominal 10 and 100 mg/L unfiltered test media, 20 and 5% immobility was recorded respectively. At 48 hours, 40 and 15% immobility was recorded respectively.

Test conditions

Hardness:

ca. 174 mg CaCO3/L

Test temperature:

ca. 20C

pH:

7-8

Dissolved oxygen:

92 to 99%

Salinity:

not measured

Nominal and measured concentrations:

The respective geometric mean measured total concentrations were 0.100, 0.222, 0.514, 1.25, 2. 71, 5.13 and 58.2 mg/L, corresponding to 100, 101, 103, 104, 104, 51.3 and 58.2% of the nominal Beta Ketosulfide concentrations, respectively. When the nominal treatment level of 10 mg/L was filtered before it was analysed, the mean measured total concentration was 0.825 mg/L instead of the unfiltered concentration of 5.13 mg/L. The two highest treatments had significant amounts of suspended materials present.

Details on test conditions:

The test was performed as a 48-hour semi-static (with renewal of test media at 24 hours) definitive test. Four replicate test vessels were prepared for each nominal and control treatment. Five juvenile D. magna (<24 hours old) were added to each replicate vessel, using a wide bore glass pipette to avoid damaging the animals during transfer. The D. magna were not fed during the test.After approximately 24 and 48 hours, the D. magna in each test vessel were observed for evidence of immobility.A D. magna was considered immobile if, when the contents of the test vessel were briefly agitated, the animals did not swim during a 15-second period of observation. The observations differentiated between animals immobilised and submerged in the body of the test media and those that were immobilised and held at the surface of the test media. The observations were perfonned before the animals were transferred to new media at 24 hours.The pH, dissolved oxygen concentration(% ASV) and individual test vessel temperatures were determined in new test media at the start of the test and at 24 hours and in old test media at 24 and 48 hours. Temperature was also monitored continuously during the test (digital (minimax) therm ometer) in an additional vessel maintained in the study area. The total hardness and alkalinity of the freshly prepared ASTM medium was determined at the start of the test. The test was conducted with a 16-hour light: 8-hour dark photoperiod.Chemical AnalysisSamples (20 ml, unfiltered) were taken for chemical analysis from all treatments, at the start of the test (from the test medium preparation flasks) and at the end of each exposure period (from pooled replicate samples). An additional filtered sample (0.45µm filter) of the 10 mg/L test media was also taken on each occasion.Data Presentation and AnalysisThe toxicity results have been expressed in terms of measured concentrations of Beta Ketosulfide. As no significant levels of immobility occurred, statistical analysis was not required.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 2.71 mg/L

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 2.71 mg/L

Effect concentrations 3

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

>= 2.71 mg/L

Details on results:

The numbers of immobilised Daplmia magna at 24 and 48 hours, following exposure to Beta Ke tosulfide are presented below in table 1 and 2.No immobility was observed in the control treatments during the test. At measured concentrations up to 2.71 mg/L, no significant levels of immobility were recorded. A single daphnid was found to be immobile at the 0.10, 0.22, and 2.71 mg/L treatment levels.Since these results did not exceed 10% and were not related to concentration, they were not co nsidered to be related to treatment with Beta Ketosulfide.

Any other information on results incl. tables

Table 1: Immobilisation of D Magna after 24 hours exposure to Beta Ketosulfide during the definitive test

		Mobile Daphnia		Immobile Daphnia
Mean measured Total Beta Ketosulfide Conc. (mg/L)	No. of Daphnia magna exposed	Bottom	Surface	Bottom	Surface
Control	20	20	-	-	-
Solvent Control	20	20	-	-	-
0.10	20	19	-	1	-
0.22	20	20	-	-	-
0.51	^20	20	-	-	-
1.25	20	20	-	-	-
*2.71	20	20	-	-	-
**5.13^+	20	16	-	4	-
**58.2	20	19	-	1	-

Table 2: Immobilisation of D Magna after 48 hours exposure to Beta Ketosulfide during the definitive test

		Mobile Daphnia		Immobile Daphnia
Mean measured Total Beta Ketosulfide Conc. (mg/L)	No. of Daphnia magna exposed	Bottom	Surface	Bottom	Surface
Control	20	20	-	-	-
Solvent Control	20	20	-	-	-
0.10	20	19	-	1	-
0.22	20	19	-	1	-
0.51	^20	20	-	-	-
1.25	20	20	-	-	-
*2.71	20	19	-	1	-
**5.13^+	20	12	-	8	-
**58.2	20	17	-	3	-

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Based on the results or this study, the 24 and 48 hour EC50 toxicity values are both considered to be greater than a nominal concentration of 100 mg/Land a mean measured soluble concentration of 2.71 mg/L.The no observed effect concentration (NOEC) at 24 and 48 hours was considered to be >= 2.71 mg! L, the highest soluble concentration of Beta Ketosulfide in this study.

Executive summary:

The study was conducted in accordance with the requirements of OECD Chemicals Testing Guideline

No. 202 Daphnia sp. Acute Immobilisation test (adopted April 13 2004).

 

The no observed effect concentration (NOEC) at 24 and 48 hours was considered to be >= 2.71mg/L, the highest soluble concentration of Beta Ketosulfide in this study.