Hexahydromethylphthalic anhydride

Toxicity to microorganisms

Link to relevant study record(s)

Reference

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:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
Please refer to IUCLID Section 13.

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

218.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: 189-248 mg/L

Description of key information

Toxicity to microorganisms: EC50 = 219 mg/L

Key value for chemical safety assessment

EC50 for microorganisms:

219 mg/L

EC10 or NOEC for microorganisms:

70 mg/L

Additional information

Toxicity to microorganisms was assessed from read across approach data available for the structural analogue 4-MHHPA as similar chemical and ecotoxicological properties were assumed.

Toxicity to microorganisms has been investigated in an activated sludge respiration inhibition test according to OECD test methods. 4 –MHHPA caused a concentration related inhibition ranging from 14% at 58 mg/L to 99% at 1000 mg/L. The EC50 was 219 (189 – 248) mg/L with concentrations of 95.3 mg/L and below causing less that 20% inhibition and regarded as not toxic to microorganisms of a municipal sewage treatment plant. EC10, estimated from reported EC20, EC50 and EC80 values, was approximately 70 mg/L. Effects or pH on inhibition were examined and found to be the major factor in determining effects, a concentration of 1000 mg/L causing <20% inhibition when pH was adjusted back to neutral.