1,4-dimethoxybenzene

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The test conditions are sufficiently described and are in accordance with the recognised EC and OECD test guidelines. The GLP are not mentioned.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

not specified

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

No data

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: no data
- Eluate: no data
- Differential loading: no data
- Controls: controls performed
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): none used
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): not applicable
- Evidence of undissolved material (e.g. precipitate, surface film, etc): no data

Test organisms (species):

Pimephales promelas

Details on test organisms:

TEST ORGANISM
- Common name: Fathead minnow
- Strain: Pimephales promelas
- Source: From Environmental research Laboratory-Duluth culture
- Age at study initiation (mean and range, SD): 28 to 34 day old.
- Length at study initiation (lenght definition, mean, range and SD): no data
- Weight at study initiation (mean and range, SD): 0.12 g wet weight
- Method of breeding: Juvenile were cultured on recently hatched brine shrimp nauplii (Artemia sp) and frozen adult brine shrimp. All culturing was
conducted at 25+/-1°C.
- Feeding during test : the fish were not fed 24 h before nor during the toxicity tests.

ACCLIMATION: All fish were aclimated to the test chambers for 2-3 hours before introduction of the toxicants.

QUARANTINE (wild caught): not applicable

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

no data

Hardness:

44.6 (+/-1.4) -45.5 mg/L CaCO3

Test temperature:

25 +/-0.5 to 1°C

pH:

7.6 +/-0.2

Dissolved oxygen:

always superio to 60% of saturation

Salinity:

no data

Nominal and measured concentrations:

no data reported.

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type, Material, size, headspace, fill volume: Broderius & Kahl: the test chambers were constructed of glass and silicon sealant and measured 10.2x20.3x10.2 cm high or 11.4x22.9x12.7 high, and contained one or 2 L of test solution.
- Aeration: Broderius & Kahl:The dilution water in the head tanks was vigorously aerated
- Type of flow-through (e.g. peristaltic or proportional diluter): Broderius & Kahl: tests were conducted with continuous-flow water delivery and toxicant introduction similar in principle to those described by Benoit et al. (A continuous-flow mini-diluter system for toxicity testing. 1982. Water Res., 16:457-464). Flow through each chamber was 40 or 25 mL/min, affording 99% replacement in about 2h or 95% replacement in about 4h, respectively. Veith et al: flow-through proportional diluters (Mount & Brungs, 1967. A simplified dosing apparatus for fish toxicology studies. Water Res., 1:21-29) and modified Benoit continuous-flow minidiluter systems were used.
- No. of organisms per vessel: 20-25 (but not clear)
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- No. of vessels per vehicle control (replicates): 0
- Biomass loading rate: no data

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Water of Lake Superior.

OTHER TEST CONDITIONS
- Adjustment of pH: no data
- Photoperiod: Broderius & Kahl: 16 h daily light included a 30 min gradual brightening and dimming period with incandescent light to simulate dawn and dusk.
- Light intensity: at the test water surface ranged from 22 to 38 lumens/sq ft.

EFFECT PARAMETERS MEASURED: death

TEST CONCENTRATIONS
- Spacing factor for test concentrations: Broderius & Kahl: The toxicant concentrations followed a geometric series (0.8 dilution factor) for all tests.

Reference substance (positive control):

not specified

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

117 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 112-122

Details on results:

There was no control mortality in tests with juveniles

Results with reference substance (positive control):

no data

Reported statistics and error estimates:

The reproducibility of test results was demonstrated to be quite good. A pooled estimate of the 96 h LC50 value was provided for these chemicals in addition to the values calculated for the individual tests.

Validity criteria fulfilled:

yes

Remarks:

no control mortality, O2 content >60% of saturation

Conclusions:

Not harmful for fish.

Executive summary:

In a 96-h acute toxicity study, Pimephales promelas were exposed to Paradimethoxybenzene under flow through conditions. 

The 96-h LC50 was 117 mg a.i./L. There was no control mortality in tests with juveniles. 

Based on the results of this study, Paradimethoxybenzene would be not classified as harmful to Pimephales promelas in accordance with the classification system of the EU.

This toxicity study is classified as acceptable and satisfies the guideline requirement for the toxicity to fish study.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 18 to 22 June 1981

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Although not performed with standardised method and GLP, this study was well described and necessary informations were available to validate it (purity of substance, test condition and method).

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

not specified

GLP compliance:

no

Analytical monitoring:

yes

Details on sampling:

- Sampling method: all test exposure chambers were sampled at aproximately mi-depth at 0 and 96H and one of each duplicate exposure chamber at 24, 48 and 72H.
- Sample storage conditions before analysis: all samples were analyzes immediately or adequately preserved for later analysis

Vehicle:

not specified

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: a stock solution of 700 mg/l of PDMB was prepared by using column saturators (Veith and Comstock, 1975, apparatus for continuously saturating water with hydrophobic organic chemicals. J. Fish. res. Bd. Canada, 32:1849-1851). The method involved recirculating water through the test chemical achieving a stable solution in water that approached saturation
- Eluate: no data
- Differential loading: no data
- Controls: blank controls have been performed
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): not used
- Evidence of undissolved material (e.g. precipitate, surface film, etc): no data

Test organisms (species):

Pimephales promelas

Details on test organisms:

TEST ORGANISM
- Common name : Fathead minnow
- Strain: Pimephales promelas
- Source: from brood stock provided by the USEPA environmental Research Laboratory-Duluth
- Age at study initiation (mean and range, SD): 29-31 days
- Length at study initiation (lenght definition, mean, range and SD): 20.9 mm (SD: 2.489 mm)
- Weight at study initiation (mean and range, SD): 0.134 g (SD: 0.0519 g)
- Method of breeding: adults were held at 25°C in flowing water with a 16Hr light-controlled photoperiod abd fed with frozen adult brine shrimp (Artemia sp.). They were provided with asbestos pipe as spawning substrate. Eggs were spawned and fertilized on the undersides of these substrates. The embryos were tended by the male parent until eye-up at which time the substrates with embryos attached were removed to another 25°C bath where hatching occurred. Fry of similar (within 24Hr) age were transferred to flow-through rearing tanks at 25°C with a 16 Hr light photoperiod. Fry were freshly hatched brine shrimp nauplii to excess three times daily until 24Hr before a test (twice on most week-end days) and a dry flake ration (Tetramin) during their first week. Fish of approximately 30 days old were used in the toxicity tests.
- Feeding during test: not fed during tests.

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

47 mg/L CaCO3

Test temperature:

24.3°C

pH:

7.6

Dissolved oxygen:

5.9 mg/L

Nominal and measured concentrations:

Nominal: 0, 29, 49, 81, 135, 225 mg/L
Measured, stable troughout the test: 0, 16.1-17.5; 28.6-31.7; 52.5-53.2; 82.3-88.2; 149-150 (mean measured concentrations, corrected for recovery).

Details on test conditions:

TEST SYSTEM
- Test vessel: tank filled with 6.3 L of toxicant solution
- Renewal rate of test solution (frequency/flow rate): 2.6 volumes per day
- No. of organisms per vessel: 25
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- No. of vessels per vehicle control (replicates): none
- Biomass loading rate: 0.532 g/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Lake Superior water
- Total organic carbon: no data
- Particulate matter: total non-filterable residue: <1 mg/l
- Metals: Al: 1-26, Cd: <0.1, Cr: 2-20, Co: <0.5; Cu: 0.3-3.2; Fe: 2-83; Pb: 7-20; Mn: 0.2-11.5; Ni: <0.5; Zn: 1.0-2.7 µg/l
- Pesticides: no data
- Chlorine: 1.2-1.3 mg/l
- Alkalinity: no data
- Ca/mg ratio: Ca: 13.0-14.7 mg/l; Mg: 2.9-3.6 mg/l
- Conductivity: 78-86 µmhos/cm
- Culture medium different from test medium:
- Intervals of water quality measurement:hardness, alkalinity, pH, at least once during each test; water temperature: daily in each exposure chamber; dissolved oxygen: in high, medium, low and control exposure chambers at least three times (0,24, 96H) during a test if surviving fish existed in that chamber.

OTHER TEST CONDITIONS
- Adjustment of pH: no data
- Photoperiod: no data
- Light intensity: no data
Hardness: 47.0 mg/L CaCO3
Test temperature: 24.3°C
pH: 7.6
Dissolved oxygen: 5.9 mg/L

EFFECT PARAMETERS MEASURED: during exposure to toxicants the fish were routinely observed for behavioural responses (effects) and deaths.. Death was defined as the cessation of opercular movements and the inability to respond when prodded. Dead fish were removed and recorded at 3, 6, 12, 24, 48, 72 and 96h.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.6
- Test concentrations: 0, 29, 49, 81, 135, 225 mg/L

Reference substance (positive control):

not specified

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

117 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CL:112-122 mg/l

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

114 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

behaviour

Remarks on result:

other: 95% CL:111-118 mg/l

Details on results:

Behavioural abnormalities: affected fish became hypoactive, stopped schooling and lost equilibrium prior to death.
Results were calculated on the basis of the mean exposure concentrations of toxicants for the duration of the test.

Results with reference substance (positive control):

no data

Reported statistics and error estimates:

Duplicates were combined resulting in a single LC50 and EC50 estimate. Estimation of the E/LC50 was made using the "trimmed Spearman-Karber" method. Confidence limits (95%) were calculated.

Validity criteria fulfilled:

yes

Remarks:

No death within controls, O2 content throughout the test: 5.9+/-0.82 mg/l

Conclusions:

Not Harmful for fish.

Executive summary:

In a 96-h acute toxicity study, Pimephales promelas were exposed to stable concentrations of Paradimethoxybenzene. 

The 96-h LC50 was 117 mg/L. Sublethal effects: affected fish became hypoactive, stopped schooling and lost equilibrium prior to death. 

Based on the results of this study, Paradimethoxybenzene would be not classified as harmful to Pimephales promelas in accordance with the classification system of the EU.

 

This toxicity study is classified as acceptable and satisfies the guideline requirement for the acute fish toxicity study.

Reference 3

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 29 feb 1988 to 30 march 1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test conducted according to OECD guidelines and GLP.

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

One aliquot part of 100 ml was taken from the total volume of 10 L
Water temperature was 22 °C +/1 °C during toxicity testing

Vehicle:

no

Details on test solutions:

- tested substance was added to dilution water accord. ISO/DIS 7346/1, ventilated until oxygen saturation, pH prior to testing 8,0 to 8,2
- substance was homogenized with Ultra-Turrax and ultra sound bath and added into testing bath by stirring with glass-bar
- testing bath was mixed/stirred with a KPG-stirrer and a glass bar for 2 h
- testing concentrations in all testing baths were given as solution with substance sedimentation at the water surface and at the ground of the testing vessel
- To determine the actual concentration of dissolved test item, water samples were taken at the beginning of the test, after 48 and 96 h. Samples were taken from the middle of the bassin. Analytical determined mean values were above 80 %.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

Brachydanio rerio (HAMILTON-BUCHANAN)
- Origin: Hoechst AG, self breeding of "Gewerbetoxikologie"
- Age: date of birth 15. October and 24. November 1987
- Fishes were adapted to the water and surrounding conditions for at least 14 days prior to the exposure
- Water temperature: 22 +/-1 °C
- Oxygen concentration >= 80 % of oxygen saturation
- Illumination: 12 hrs per day
- Animal density: <= 1 g fish per litre water
- Feeding: twice a day, ad libitum
- Feed: Tetra Min. Tetra Werke, Melle
- Prior to testing 10 fishes were randomly picked to be representatively measured for their body size, these 10 fishes were not used for the experiment

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Test temperature:

21.7 to 22.2°C

pH:

7.6 to 8.2

Dissolved oxygen:

>= 80 %
7.7 to 8.7 mg/L

Nominal and measured concentrations:

250 mg/L concentration - concentration after 0h: 111 mg/L; after 48h: 143 mg/L; after 96h: 125 mg/L.
350 mg/L concentration - concentration after 0h: 122 mg/L; after 48h: 167 mg/L; after 96h: 199 mg/L.
100 mg/L concentration - concentration after 0h: 67,3 mg/L; after 48h: 86 mg/L; after 96h: 86,9 mg/L.
125 mg/l concentration - concentration after 0h: 109 mg/L; after 48h: 106 mg/L; after 96h: 96 mg/L.
180 mg/l concentration - concentration after 0h: 133 mg/L; after 48h: 148 mg/L; after 96h: 150 mg/L.

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

134 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

mortality (fish)

Remarks on result:

other: none

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

127 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

mortality (fish)

Remarks on result:

other: none

Details on results:

At all concentrations symptoms and lethality were observed.

Validity criteria fulfilled:

yes

Executive summary:

In a 96-h acute toxicity study (Clariant, 1988), Fish Danio rerio were exposed to concentrations of Paradimethoxybenzene from 0 to 350 mg/L, under static conditions.

The 96-h LC50 was 127 mg/L based on mortality.

Based on the results of this study, Paradimethoxybenzene would be not classified as harmful to fish in accordance with the EU classification criteria.

 

This toxicity study is classified as acceptable and satisfies the guideline requirement for the acute fish toxicity study.

Description of key information

 Pimephales promelas were exposed to Paradimethoxybenzene under static or flow through conditions. In the three selected key studies, the LC50 range was 117-127 mg/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

117 mg/L

Additional information

Three studies of reliability 2 according to Klimisch were available and were chosen as key studies.

In the first 96-h acute toxicity study (Brooke et al., 1984), Pimephales promelas were exposed to Paradimethoxybenzene under flow through conditions. The 96-h LC50 was 117 mg a.i./L.

The sublethal effects were: affected fish became hypoactive, stopped schooling and lost equilibrium prior to death. 

In the second 96-h acute toxicity study (Broderius et al., 1983 and Veith et al., 1985), Pimephales promelas were exposed to Paradimethoxybenzene under flow through conditions. 

The 96-h LC50 was 117 mg a.i./L. There was no control mortality in tests with juveniles. 

In the third study (Clariant, 1988), fish Danio rerio were exposed to concentrations of Paradimethoxybenzene from 0 to 350 mg/L, under static conditions.

The 96-h LC50 was 127 mg/L based on mortality.

Based on the results of these studies, Paradimethoxybenzene should not be considered as harmful for fish, according to EC classification criteria.