Benzene, 1,1'-oxybis[methyl-, sulfonated, ammonium salts

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

5 February - 13 March 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study generally follows test guideline OECD203. The test report is without detailed documentation. The test parameters documented do not totally comply with the specific testing guideline, but are sufficient to accept the data.

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

yes

Remarks:

In the present study, one fish died, and no full-test was conducted. However, as this mortality rate corresponds to 14% lethality, it can be safely assumed that the LC50 is greater than the tested concentration.

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Vehicle:

no

Remarks:

Direct dispersion in water

Details on test solutions:

PREPARATION AND APPLICATON OF TEST SOLUTION
The following test aquaria were set up:
- Test solution (Tn); containing natural water with test item (1 aquarium with 7 fish)
- Blank control (Bn); containing pure natural water (1 aquarium with 7 fish)
To allow for equilibration of pH and ensure sufficient oxygenation, the natural water used for the test was aerated for at least 24 h before preparing the test media.
Since the test item is soluble, it was added directly to the aerated natural water and stirred until dissolution. The test was performed under semi-static exposure conditions with renewal of the test medium at 24, 48 and 72 h.
In the blank control, only the aerated natural water mentioned above was used.
At least 1 h before the start of the exposure (addition of fish to the test medium), the test vessels were filled with the test solutions to allow for equilibration of pH, oxygen and temperature. The pH was adjusted to pH 6.5–7.0.
A fine-mesh dip net was used to transfer fish, taking care to minimise possible stress due to handling. The transfer was performed in an impartial manner to eliminate bias (as regards weight and length of the fish). Fish which were damaged or dropped during the transfer were not used.
After 24, 48 and 72 h, new test media (test solution and blank control) were prepared as described above and the fish were transferred to these fresh test media.
- Evidence of unsolved material: Not relevant. Since the test item is soluble, it was added directly to the aerated natural water and stirred until dissolution.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Test organism: Danio rerio (zebrafish)
- Culturing: Young fish are held under quarantine conditions in 40 l glass aquaria until use in the test.
- Illumination: 16 h a day
- Temperature: 21–25 °C, controlled by a thermostat at ±2 °C
- Medium: Continuously aerated natural water of the town of Schlieren
- Feeding: Daily, except on week-ends. On Fridays, a triple dose is given.

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

Aprox. 26.8 mg/l as CaCO3

Test temperature:

21 - 22°C

pH:

7.0 - 8.5

Dissolved oxygen:

7.3 - 8.2 mg/l

Salinity:

not reported

Conductivity:

not reported

Nominal and measured concentrations:

The concentration of the main component of Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50% ) was measured by HPLC at the beginning of the test, as well as after 24, 48, 72 (in the fresh and in the old medium) and 96 h of exposure (Table 3). These analyses confirmed the right dosage of the test item and showed that the test concentration remained stable over the 96-h test period and was within 80-120% of the nominal concentration. The measured concentrations in the fresh medium at the beginning of the test and after renewal at 24, 48 and 72 h were 11.9, 11.6, 12.3 and 11.8 mg/l, respectively. In the old media at 24, 48, 72 and 96 h they were respectively 11.4, 12.1, 13.1 and 10.8 mg/l. These values corresponded to 95-115% of the nominal concentration.
Therefore, the effective concentrations were assessed based on the nominal concentration of the main component of the test item.

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass aquaria filled with 1.25 l of water
- Test medium: Continuously aerated natural water of the town of Schlieren
- Oxygen concentration: The total dissolved oxygen content is kept at >60% of the saturation value with aeration via Pasteur pipettes
- Number of fish: 7 fish per test concentration and control (target: length of 1–3 cm, total loading =1 g fish weight/l)
- Light: 16 h photoperiod a day, supplied by overhead white fluorescent tubes, no transition period
- Temperature (target): 21–25 °C, controlled by a thermostat at ±2 °C
- Test type: Semi-static exposure conditions, with renewal of the test medium every 24 h (stability of test item not known)
- Test duration: 96 h
- Feeding: the fish are not fed during the test

RANGE FINDING STUDY
This study was performed as a limit test at 11.4 mg/l concentration of the main component of Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50% ), corresponding to 23.8 mg/l of the test item.
This concentration was chosen based on preceding acute toxicity studies with algae (ACH study no. A17-00075) and Daphnia (ACH study no. A17-00076), where an ErC50 of 17.8 mg/l and a 48 h EC50 of 11.4 mg/l, respectively, were determined.
Since no information about the stability of the test item in natural water was available, and since stable concentrations are a requirement of the test guideline OECD 203, the test was performed under semi-static conditions, with a renewal of the test solution at 24, 48 and 72 h.

EFFECT PARAMETERS MEASURED
Toxic effects other than mortality, such as loss of coordination, hypo- or hyperactivity and swimming on the back, were not observed during the first 72 h of exposure. Some fish showed minor distressed behaviour after 96 h.

DEVIATION FROM GUIDELINES
According to TG OECD 203, “If any mortalities occur [in a Limit-test such as the present study], a full study should be conducted.”. In the present study, one fish died, and no full-test was conducted. However, as this mortality rate corresponds to 14% lethality, it can be safely assumed that the LC50 is greater than the tested concentration. From an ethical and animal welfare point of view, it was judged that the performance of a full-test was not justified

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

>= 11.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

11.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

The no-observed-effect concentration (NOEC) was 11.4 mg/l nominal concentration of the main component of Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50% ).
Based on the mortality data and the tested concentration, the median lethal concentration (LC50) of the main component (CAS 75314-26-0) of Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50% ) to Danio rerio (Zebrafish) is >11.4 mg/l.

Reported statistics and error estimates:

The effective concentrations LCx were assessed based on the nominal concentration of the main component of the test item.
No statistical analysis was performed.

Validity criteria fulfilled:

yes

Conclusions:

The acute lethal toxicity of the main component of Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50%) (CAS no. 75314-26-0) to Zebrafish Danio rerio was determined in a 96 hour semi-static test according to OECD guideline 203. The median effect concentrations (LC50) of the main component of Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50%) on Zebrafish Danio rerio were estimated to be 11.4 mg/l nominal concentration after 96 h of exposure. The NOEC values were determined to be 11.4 mg/l nominal concentration after 96 h of exposure. The results of the test can be considered reliable without restriction.

Executive summary:

The acute lethal toxicity of Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50%) to the Zebrafish Danio rerio was investigated according to test guideline OECD 203, under semi-static exposure conditions over a period of 96 h.

The only applied nominal concentration was 11.4 mg/l of the main component (CAS no.75314-26-0), corresponding to 23.8 mg/l of the test item. Therefore, this study represents a limit test. This concentration was chosen based on preceding acute toxicity studies with algae (ACH study no. A17-00075) and Daphnia (ACH study no. A17-00076), where an ErC50 of 17.8 mg/l and a 48 h EC50 of 11.4 mg/l of the main component, respectively, were determined.

The test item Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50%) is a viscous liquid, 47.9% pure and is soluble in water. Therefore, the test medium was prepared by direct addition of the test item to natural water and stirred until dissolution. The test was performed under semi-static exposure conditions with renewal of the test medium at 24, 48 and 72 h.

Seven fish were exposed to the test item, and seven were used as a blank control.

The concentration of the main component of Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50%) was measured by HPLC at the beginning of the test and after 24, 48, 72 and 96 h. These analyses confirmed the right dosage of the test item and showed that the test concentration remained stable over the 96-h test period (95% of nominal concentration) and was within 80-120% of the nominal concentration. Therefore, the effective concentrations were assessed based on the nominal concentration of the main component of the test item.

At the nominal concentration of 11.4 mg/l of the main component of Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50%), one of a total of seven fish died after 72 h of exposure. No mortality was observed in the blank control.

Toxic effects other than mortality, such as loss of coordination, hypo- or hyperactivity and swimming on the back, were not observed during the first 72 h of exposure. Some fish showed minor distressed behaviour after 96 h.

The no-observed-effect concentration (NOEC) was 11.4 mg/l nominal concentration of the main component of Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50%).

Based on the mortality data and the tested concentration, the median lethal concentration (LC50) of the main component (CAS no.75314-26-0) of Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50%) to Danio rerio (Zebrafish) is >11.4 mg/l.

All validity criteria were fulfilled.

Description of key information

The acute lethal toxicity of the main component of Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50%) (CAS no. 75314-26-0) to Zebrafish Danio rerio was determined in a 96 hour semi-static test according to OECD guideline 203 (ACH, 2017).

The only applied nominal concentration was 11.4 mg/l of the main component (CAS no.75314-26-0), corresponding to 23.8 mg/l of the test item. Therefore, this study represents a limit test. This concentration was chosen based on preceding acute toxicity studies with algae (ACH study no. A17-00075) and Daphnia (ACH study no. A17-00076), where an ErC50 of 17.8 mg/l and a 48 h EC50 of 11.4 mg/l of the main component, respectively, were determined.

The median effect concentrations (LC50) of the main component of Benzene, 1,1’-oxybis(methyl-, sulfonated, ammonium salt (ca 50%) on Zebrafish Danio rerio were estimated to be > 11.4 mg/l nominal concentration after 96 h of exposure. The NOEC values were determined to be 11.4 mg/l nominal concentration after 96 h of exposure. The results of the test can be considered reliable without restriction.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

11.4 mg/L