1,3-dichlorobenzene

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Conducted according to the 1984 OECD 202 guideline. A significant deviation from the current guideline is that analytical verification of test concentrations was only conducted at 0h and 24h (old solutions). However, given the known solubility and stability of the test item, this deviation should not invalidate the studies reliability for use in hazard assessment. All relevant validity criteria of OECD 202 were met.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

(1984)

Deviations:

no

GLP compliance:

not specified

Analytical monitoring:

yes

Remarks:

- Concentrations: Concentrations of 0.56, 1.0, 1.8, 3.2 and 5.6 mg/L were measured at 0 and 24 hours (old) only.

Details on sampling:

- Concentrations:
- Sampling method: At the start of the test and after 24 hour, two 20 mL samples of the test solution (two 40 mL samples for the 0.56 mg/L and control groups) were collected at each concentration.
- Sample storage conditions before analysis: Not applicable

Vehicle:

yes

Remarks:

2:3 mixture of ethanol:hardened castor oil (HC0-40)

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
The required amount of test substance was weighed using an electronic balance. A 5-fold volume of a 2:3 mixture of ethanol:hardened castor oil (HC0-40) was added as a dissolution aid and mixed thoroughly, after which dechlorinated water was added to make a constant volume of 100 mL (reference solution). The reference solution required to prepare 1000 mL of test solution at the nominal concentrations of 0.56, 1.0, 1.8, 3.2 and 5.6 mg/L was dispensed using a volumetric pipette into a 1000 mL volume beaker, made up to a fixed volume of 1000 mL with dechlorinated water and stirred, then immediately poured into four test containers to the brim and sealed.

Test organisms (species):

Daphnia magna

Details on test organisms:

Juvenile Daphnia magna were used in the study within 24 hours of birth.
This species was obtained from the National Institute for Environmental Studies (NIES), and was successively bred at Sumika Technoservice Corporation.
Visibly healthy adult female Daphnia magna of sufficient size and bearing larvae were selected from those being reared, and were transferred to a separately prepared container. The next day, the larvae released from the females were divided into a separate container. These larvae were used as parents for the test Daphnia magna and were reared for 2 to 4 weeks under the conditions described below. Once the parents had matured and were producing larvae, these larvae were removed at least twice a week. After 2-4 weeks, female adults with larvae in the brood pouch were selected on the day before the start of exposure, and the larvae released the next day (within 24 hours) were used for the test. However, daphnids from batches with many dead individuals, dormant eggs or males were not used.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

Standard guideline exposure duration

Post exposure observation period:

None

Hardness:

71.8 mg/L (CaCO3 equivalent)

Test temperature:

Test temperature during a 48-hour semi-static exposure of Daphnia magna to the test item (measured at 0h (new medium), 24h (new and old medium), and 48h (old medium))
Control: 19.4 - 20.6
Solvent Control: 19.4 - 20.6
0.56 mg/L: 19.4 - 20.6
1.0 mg/L: 19.4 - 20.6
1.8 mg/L: 19.4 - 20.6
3.2 mg/L: 19.4 - 20.6
5.6 mg/L: 19.4 - 20.6

pH:

pH values during a 48-hour semi-static exposure of Daphnia magna to the test item (measured at 0h (new medium), 24h (new and old medium), and 48h (old medium))
Control: 8.2 - 8.2
Solvent Control: 8.1 - 8.2
0.56 mg/L: 81. - 8.2
1.0 mg/L: 8.2 - 8.3
1.8 mg/L: 8.2 - 8.2
3.2 mg/L: 8.2 - 8.2
5.6 mg/L: 8.2 - 8.2

Dissolved oxygen:

Dissolved oxygen concentrations (mg/L) during a 48-hour semi-static exposure of Daphnia magna to the test item (measured at 0h (new medium), 24h (new and old medium), and 48h (old medium))
Control: 8.1 - 8.5
Solvent Control: 8.1 - 8.9
0.56 mg/L: 8.4 - 8.8
1.0 mg/L: 8.4 - 8.7
1.8 mg/L: 8.4 - 8.8
3.2 mg/L: 8.4 - 8.8
5.6 mg/L: 8.6 - 8.8

Nominal and measured concentrations:

Nominal concentrations (0.56, 1.0, 1.8, 3.2 and 5.6 mg/L) plus an untreated and vehicle control
Measured Concentrations (GMM): 0.50, 0.90, 1.6, 2.9 and 5.3 mg/L, which were 89-95% of the nominal values.

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL glass, lidded, wide-mouth bottle (140 mL capacity when filled with no headspace)
- Type (delete if not applicable): closed
- Fill volume: 140 mL
- Volume of solution: 140 mL
- Aeration: No
- 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): 5
- No. of vessels per vehicle control (replicates): 4
- Biomass loading rate:

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Dechlorinated water (Takarazuka City tap water treated by UV irradiation)
- Total organic carbon: Not specified
- Particulate matter: Not specified
- Metals: Not specified
- Pesticides: Not specified
- Chlorine: Not specified
- Alkalinity: Not specified
- Ca/mg ratio: Not specified
- Conductivity: Not specified
- Salinity: Not specified
- Culture medium different from test medium: Not specified
- Intervals of water quality measurement: Temperature, dissolved oxygen and pH were measured in the test solution at all concentrations at start of exposure and 24 and 48 hr after exposure (before and after water change in each test container).

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16h light: 8h dark
- Light intensity: Not specified

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): The number of immobilised daphnids was observed 24 and 48 hours after the start of exposure.

VEHICLE CONTROL PERFORMED: yes

RANGE-FINDING STUDY
- Test concentrations: 1.0, 1.4, 1.8, 2.4 and 3.2 mg/L
- Results used to determine the conditions for the definitive study: Yes

Reference substance (positive control):

yes

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

2.5 mg/L

95% CI:

>= 2.2 - <= 2.9

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

2.9 mg/L

95% CI:

>= 2.5 - <= 3.4

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: None reported
- Observations on body length and weight: None reported
- Other biological observations: None reported
- Other adverse effects control: None reported
- Immobilisation of control: No immobilisation of control
- Abnormal responses: None reported
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values:
- Effect concentrations exceeding solubility of substance in test medium: No

Results with reference substance (positive control):

The 48 hr EiC50 of the acute immobilisation test using a reference substance (potassium dichromate, reagent grade, Lot No. KCE6888, Wako Pure Chemical Industries) was 0.72 mg/L.

Reported statistics and error estimates:

The immobilisation rate (%) was calculated from the number of immobilised daphnids at each concentration and the number of daphnids tested (20 daphnids), and the 50% immobilisation concentration (EiC50) was estimated using the Probit method. The 95% confidence intervals were also estimated.

Table 1. Measured Concentrations of m-dichlorobenzene during a 48 hour exposure of Daphnia magna under semi-static test conditions

Nominal Concentration (mg/L)	Measured Concentration (mg/L)			% Nominal
	0 hour (new)	24 hour (old)	Geometric Mean
Control	< 0.01	< 0.01	-	-
Solvent Control	< 0.1	< 0.1	-	-
0.56	0.53	0.48	0.50	89
1.0	0.90	0.90	0.90	90
1.8	1.7	1.6	1.6	89
3.2	3.0	2.8	2.9	91
5.6	5.5	5.2	5.3	95

New: freshly prepared test solutions
Old: test solutions after 24 hour exposure period

 

Table 2. Immobility of Daphnia magna exposed to m-dichlorobenzene under semi-static test conditions

Nominal Concentration (mg/L)	Cumulative Number of Dead or Immobilised Daphnia (%)
	24 hour	48 hour
Control	0 (0)	0 (0)
Solvent Control	0 (0)	0 (0)
0.56	0 (0)	0 (0)
1.0	0 (0)	0 (0)
1.8	1 (5)	2 (10)
3.2	12 (60)	16 (80)
5.6	20 (100)	20 (100)

 

Validity criteria fulfilled:

yes

Remarks:

- immobilisation in the control vessels was <10 % - Dissolved oxygen concentrations were ≥ 3 mg/L in all test vessels throughout the test

Conclusions:

The 48h EC50 of m-dichlorobenzene to Daphnia magna was 2.5 mg/L (95 % CI: 2.2 - 2.9). All relevant validity criteria were met.

Executive summary:

The 48h EC50 of m-dichlorobenzene to Daphnia magna was determined in accordance with OECD Guideline 202 (1984).  The definitive test was conducted at nominal test concentrations of 0.56, 1.0, 1.8, 3.2 and 5.6 mg/L, including a blank control and solvent control in a semi-static regime (24h changeover).  Analytical verification of test concentrations was conducted at 0h (new test solutions) and 24h (old test solutions) only.  Analytical results indicated that test solutions remained within ± 20 % of nominal test concentrations, and thus nominal test concentrations were used to estimate the 24 and 48 h EC50 values.  The 48h EC50 of m-dichlorobenzene to Daphnia magna was 2.5 mg/L (95 % CI: 2.2 - 2.9).  All relevant validity criteria were met.

Description of key information

48h EC50 = 2.5 mg/L; OECD 202 (1984); MITI 1995

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

2.5 mg/L

Additional information

OECD 202 (MITI, 1995)

The 48h EC50 of m-dichlorobenzene to Daphnia magna was determined in accordance with OECD Guideline 202 (MITI, 1995).  The definitive test was conducted at nominal test concentrations of 0.56, 1.0, 1.8, 3.2 and 5.6 mg/L, including a blank control and solvent control in a semi-static regime (24h changeover).  Analytical verification of test concentrations was conducted at 0h (new test solutions) and 24h (old test solutions) only.  Analytical results indicated that test solutions remained within ± 20 % of nominal test concentrations, and thus nominal test concentrations were used to estimate the 24 and 48 h EC50 values.  The 48h EC50 of m-dichlorobenzene to Daphnia magna was 2.5 mg/L (95 % CI: 2.2 - 2.9).  All relevant validity criteria were met.