3,5-xylenol

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

20 October 2004 to 22 October 2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Mixed xylenols

IUPAC Name:

Mixed xylenols

Details on test material:

- Name of test material (as cited in study report): Mixed xylenols
- Substance type: Phenols
- Physical state: liquid
- Analytical purity: 99.74%
- Impurities (identity and concentrations): not stated
- Composition of test material, percentage of components: 2,5-xylenol: 16.4%; 3,4-xylenol: 16.9%; 2,4-xylenol: 22.7%; 3,5-xylenol: 11.1%; 2,3-xylenol: 18.2%; 2,6-xylenol: 14.7%
- Isomers composition: 2,5-xylenol: 16.4%; 3,4-xylenol: 16.9%; 2,4-xylenol: 22.7%; 3,5-xylenol: 11.1%; 2,3-xylenol: 18.2%; 2,6-xylenol: 14.7%
- Purity test date: not stated
- Lot/batch No.: 20 NOV 2003
- Expiration date of the lot/batch: 31 July 2005
- Stability under test conditions: not stated
- Storage condition of test material: Room temperature in the original container in a dark ventilated cabinet.

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

At 0 and 48 hours one sample from each test solution and control was analysed for ethyl phenols. Three QC samples were also prepared at each sampling interval at nominal concentrationsof 1.00 to 50.0 mg/L and these were analysed at the same time as the test samples. Analysis was performed by GC/FID.

Test solutions

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: solvent for test substance
- Eluate: not applicable
- Differential loading: not applicable
- Controls: Untreated media for control and acetone solvent control
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): organic solvent
- Concentration of vehicle in test medium (stock solution and final test solution): 0.10 mL acetone/L water
- Evidence of undissolved material (e.g. precipitate, surface film, etc): none stated

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain: not applicable
- Source: Cultures maintained at Springborn Smithers Laboratories, USA
- Age at study initiation (mean and range, SD): <24 hours old
- Weight at study initiation (mean and range, SD): not applicable
- Length at study initiation (length definition, mean, range and SD): not applicable
- Valve height at study initiation, for shell deposition study (mean and range, SD): not applicable
- Peripheral shell growth removed prior to test initiation: not applicable
- Method of breeding: parthenogenetic
- Feeding during test
- Food type: Not fed during test
- Amount: Not fed during test
- Frequency: Not fed during test

ACCLIMATION
- Acclimation period: not applicable
- Acclimation conditions (same as test or not): not applicable
- Type and amount of food: Unicellular green alga, Ankistrodesmus falcatus, 4 x 10E7 cells/mL and a suspension of YCT (yeast, cereal leaves and flaked fish food)
- Feeding frequency: daily
- Health during acclimation (any mortality observed): <20% mortality in the 48 hours prior to test initiation

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

Total hardness CaCO3: 190 mg/L

Test temperature:

19 - 21°C

pH:

pH 8.1-8.4

Dissolved oxygen:

8.7 - 9.5 mg/L ab (9.4 mg/L at test start)

Nominal and measured concentrations:

Nominal: 3.1, 6.3, 13, 25 and 50 mg/L
Mean measured: 2.0, 5.4, 11, 21 and 47 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 250 mL glass vessels with Teflon lined screw tops. Each vessel contained 200 mL of test solution.
- Aeration: none (volatile test substance)
- Type of flow-through (e.g. peristaltic or proportional diluter): not applicable
- Renewal rate of test solution (frequency/flow rate): not applicable
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- No. of vessels per vehicle control (replicates): 4
- Biomass loading rate: not stated

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Fortified well water based on the formulation for hard water (US EPA method) and then filtration through an Amberlite XAD-7 resin column.
- Total organic carbon:
- Particulate matter: none observed
- Metals:none found
- Pesticides: none found
- Chlorine: not stated
- Alkalinity: 120 mg/L (as CaCO3)
- Ca/mg ratio: hardness of 190 mg/L
- Conductivity: 500 µmhos/cm for dilution water
- Culture medium different from test medium: no
- Intervals of water quality measurement: At 0 and 48 hours.

OTHER TEST CONDITIONS
- Adjustment of pH:
- Photoperiod: 16 hours light / 8 hours dark
- Light intensity: 77 to 96 footcandles

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : The number of immobilised Daphnia in each test vessel were recorded at 0 and 48 hours. Daphnia were considered to be immobile if they were not able to swim within 15 seconds after gentle agitation.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: approx. 2
- Justification for using less concentrations than requested by guideline: not applicable
- Range finding study
- Test concentrations: 10, 100 and 1000 mg/L and 0.0010, 0.010, 0.10, 1.0 and 10 mg/L
- Results used to determine the conditions for the definitive study:yes

Reference substance (positive control):

not specified

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

10 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL: 5.4-21 mg/L

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

7.7 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL: 5.4-11 mg/L

Effect concentrations 3

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

5.4 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: not stated
- Observations on body length and weight: not applicable
- Other biological observations: After 48 hours of exposure, 100% of the daphnids were immobilised in the 11, 21 and 47 mg/L treatment levels. No immobilisation or sublethal effects were observed in the daphnids exposed to the 2.0 and 5.4 mg/L treatments, nor in the controls.
- Mortality of control: none observed
- Other adverse effects control: none observed
- Abnormal responses: none observed
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: none observed
- Effect concentrations exceeding solubility of substance in test medium: not applicable

Results with reference substance (positive control):

No reference substance reported.

Any other information on results incl. tables

Throughout the exposure period the analytical measurements generally approximated the nominal concentrations. The low recoveries in the 1.00 mg/L QC samples resulted from limitations due to the nature of the test substance. Results for the QC samples were recoveries of 63.4 - 63.5% for the 2.00 mg/L samples and 84.7 - 108% for the 10.0 and 50.0 mg/L samples, therefore appropriate precision was demonstrated.

After 48 hours of exposure, 100% of the daphnids were immobilised in the 11, 21 and 47 mg/L treatment levels. No immobilisation or sublethal effects were observed in the daphnids exposed to the 2.0 and 5.4 mg/L treatments, nor in the controls.

Table 1: Concentrations of mixed xylenols measured in exposure solutions during a 48 hour static exposure of Daphnia magna

Nominal concentration (mg/L)	Measured concentration (mg/L)
	0 hour	48 hours	Mean	% of nominal
Control	<0.14	<0.14	NA	NA
Solvent control^a	<0.14	<0.14	NA	NA
3.1	2.0	1.9	2.0	64
6.3	5.7	5.2	5.4	86
13	12	10	11	85
25	23	20	21	85
50	45	49	47	94

NA = not applicable
^a= acetone was used in the solvent control and in each test vessel at a concentration of 0.1mL/L.

 

Table 2: Mean measured concentrations tested, corresponding cumulative percent, number of immobilisedDaphniaand observations recorded during the 48 hour static exposure of mixed xylenols to Daphnia magna

Mean measured concentration (mg/L)	Cumulative percent immobilisation (%)^a
	24 hours					48 hours
	A	B	C	D	Mean	A	B	C	D	Mean
Control	0 (0)	0 (0)	0 (0)	0 (0)	0	0 (0)	0 (0)	0 (0)	0 (0)	0
Solvent control	0 (0)	0 (0)	0 (0)	0 (0)	0	0 (0)	0 (0)	0 (0)	0 (0)	0
2.0	0 (0)	0 (0)	0 (0)	0 (0)	0	0 (0)	0 (0)	0 (0)	0 (0)	0
5.4	0 (0)	0 (0)	0 (0)	0 (0)	0	0 (0)	0 (0)	0 (0)	0 (0)	0
11	80 (4)	60 (3)	60 (3)	40 (2)	60^b	100 (5)	100 (5)	100 (5)	100 (5)	100
21	100 (5)	100 (5)	100 (5)	100 (5)	100	100 (5)	100 (5)	100 (5)	100 (5)	100
47	100 (5)	100 (5)	100 (5)	100 (5)	100	100 (5)	100 (5)	100 (5)	100 (5)	100

^a= Actual number of immobilised daphnids is presented in parentheses.
^b= Several surviving daphnids were observed to be on the surface of the test solution.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 24 hour EC50 for mobility was determined to be 10.0 mg/L.
The 48 hour EC50 for mobility was determined to be 7.7 mg/L.