4-chloroformylphthalic anhydride

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1991-04-30 to 1991-07-10

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study performed according to appropriate guideline and GLP, unable to confirm conformity of replicate control respiration rates.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

yes

Specific details on test material used for the study:

Trimetillic anhydride

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge of a predominantly domestic sewage

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

>= 100 - <= 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

The 3-hour EC50 obtained from the test was between 100 and 500 mg/L.

Results with reference substance (positive control):

The positive control, 3,5-dichlorophenol, exhibited an EC50 of 10.2 mg/L in the range-finding test and 4.6 mg/L in the definitive test.

Table 1: Effects on the respiration rate of activated sludge following 3 -h exposure to trimellitic anhydride (Range-finder data)

Trimellitic anhydride nominal concentration (mg/L)	Respiration rate, mg O2/L*h	Respiration inhibition (%) relative to control
0.0 (control)	97.8	-
1	107.28	stimulation
10	97.2	0.6
100	91.5	6
7.5 mg 3,5-DCP/L (reference inhibitor)	62.58	36
15.0 mg 3,5-DCP/L (reference inhibitor)	30.9	68
30.0 mg 3,5-DCP/L (reference inhibitor)	13.92	86

 

Table 2: Effects on the respiration rate of activated sludge following 3 -h exposure to trimellitic anhydride (Definitive test data)

Trimellitic anhydride nominal concentration (mg/L)	Respiration rate, mg O2/L*h	Respiration inhibition (%) relative to control
0.0	153.6	-
500	8.16	95
1000	1.32	99
2000	0.78	99.5
4000	0.78	99.5
7.5 mg 3,5-DCP/L (reference inhibitor)	51.6	66
15.0 mg 3,5-DCP/L (reference inhibitor)	10.2	93
30.0 mg 3,5-DCP/L (reference inhibitor)	4.5	97

 

Validity criteria fulfilled:

yes

Remarks:

The EC50 of the reference inhibitor 3,5-DCP was 10 mg/L and 5 mg/L (rounded values) in the range-finder and definitive tests, respectively. No information presented in the report about the conformity of respiration rates in replicate control vessels.

Conclusions:

The respiration of activated sludge was unaffected by 3-h exposure to trimellitic anhydride at nominal concentrations of up to 100 mg/L, but profound inhibition occurred at concentrations equal to or greater than 500 mg trimellitic anhydride/L. Based on the combined observations of a range-finder and definitive test, and nominal concentrations, the 3-hour EC50 was >100, <500 mg trimellitic anhydride/L.

Executive summary:

The toxicity of trimellitic anhydride (source substance) was determined in an activated sludge respiration inhibition test according to OECD guideline 209. Activated sludge obtained from a predominantly domestic sewage plant was exposed over a period of three hours to trimellitic anhydride at nominal concentrations of 1, 10 and 100 mg/L in a preliminary range-finder and at 500, 1000, 2000 and 4000 mg/L in the subsequent definitive test. Inhibition, relative to the control rate, was <10% in all the range-finder treatments, but >/=95% in all the definitive test treatments. The 3 -h EC50 could not be calculated reliably, but it lies in the range >100, <500 mg trimellitic anhydride/L.

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

The justification of the read across is described in the document attached below.

Reason / purpose for cross-reference:

read-across source

Specific details on test material used for the study:

4-chloroformylphthalic anhydride

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

100 - 500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Validity criteria fulfilled:

not applicable

Conclusions:

The respiration of activated sludge was unaffected by 3-h exposure to trimellitic anhydride (source substance) at nominal concentrations of up to 100 mg/L, but profound inhibition occurred at concentrations equal to or greater than 500 mg trimellitic anhydride/L. Based on the combined observations of a range-finder and definitive test, and nominal concentrations, the 3-hour EC50 was between 100 and 500 mg/L.

Executive summary:

The toxicity of trimellitic anhydride (source substance) was determined in an activated sludge respiration inhibition test according to OECD guideline 209. Activated sludge obtained from a predominantly domestic sewage plant was exposed over a period of three hours to trimellitic anhydride (source substance) at nominal concentrations of 1, 10 and 100 mg/L in a preliminary range-finder and at 500, 1000, 2000 and 4000 mg/L in the subsequent definitive test. Inhibition, relative to the control rate, was <10% in all the range-finder treatments, but >/=95% in all the definitive test treatments. The 3-h EC50 could not be calculated reliably, but it lies in the range >100, <500 mg/L.

Based on the close structural similarity of trimellitic anhydride (source substance) and trimellitic anhydride mono-chloride (target substance), these results can be taken into account for the target substance.

Description of key information

Read-across, OECD guideline 209, GLP, key study, validity 2:

Toxicity to microorganisms: 100 mg/L< EC50 < 500 mg/L; NOEC = 100 mg/L based on nominal concentrations.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

100 mg/L

Additional information

In a reliable study of the toxicity of trimellitic anhydride to aquatic microorganisms (Lebertz, 1991b), the 3 hour EC50, based on inhibition of respiration of activated sludge, was between 100 and 500 mg trimellitic anhydride-equiv/L. Inhibition, relative to the untreated control, was observed at concentrations ≥ 500 mg/L and the NOEC was 100 mg/L.

Rapid hydrolysis of the anhydride to trimellitic acid is presumed to have occurred under the conditions of the test and it is likely that salts were formed by interaction between trimellitic acid and the mineral constituents of the synthetic sewage present in the test system.

No pH measurements were reported; consequently it is uncertain to what degree a lowering of pH may have caused or contributed to the observed effect.

Based on the close structural similarity of trimellitic anhydride (source substance) and trimellitic anhydride mono-chloride (target substance), these results can be taken into account for the target substance.