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Diss Factsheets

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Administrative data

Link to relevant study record(s)

Description of key information

In this study 3,3’,4,4’-Benzophenonetetracarboxylic dianhydride (BTDA) was found to inhibit the growth of the freshwater green alga Desmodesmus subspicatus after 72 hours with the following effect values (nominal test item concentrations). The NOEC-values for both inhibition of growth rate and yield after 72 hours were 25.0 mg/L. The LOEC-values for both inhibition of growth rate and yield after 72 hours were 50.0 mg/L. The EC50-value for inhibition of specific growth rate (ErC50) after 72 hours was 68.6 (50.0 – 100) mg/L. The EC50-value for inhibition of yield (EyC50) with 95 % confidence intervals after 72 hours was 51.9 (48.6 – 55.5) mg/L. The toxic effects were caused by the low pH values in the two highest test concentrations. No effects were found at a concentration of 100 mg/L at neutral pH values. 

Key value for chemical safety assessment

EC50 for freshwater algae:
68.6 mg/L
EC10 or NOEC for freshwater algae:
25 mg/L

Additional information

The toxicity of 3,3’,4,4’-Benzophenonetetracarboxylic dianhydride (BTDA) to the unicellular freshwater green alga Desmodesmus subspicatus was determined according to the principles of OECD 201 at Dr.U.Noack-Laboratorienin 31157 Sarstedt, Germany from 2012 -09 -18 to 2012 -09 -21. The aim of the study was to assess the effects on growth rate and yield over a period of 72 hours. The study was conducted under static conditions with an initial cell density of 4332 cells/mL. Based on a preliminary test, 5 concentration levels were tested in a geometrical series with a dilution factor of 2 (nominal): 6.25 - 12.50 - 25.0 - 50.0 - 100 mg/L. Three replicates were tested for each test item concentration and six replicates for the control. Three replicates of the highest test concentration were additionally tested with an initial pH value of 8.04 to test for pH-related effects. Environmental conditions were determined to be within the acceptable limits. The concentrations of 3,3’,4,4’-Benzophenonetetracarboxylic dianhydride were analytically verified by HPLC-DAD on the basis of the corresponding transformation product 3,3’,4,4’-Benzophenonetetracarboxylic acid (BTA) at test start and test end of all test concentrations and the control. The measured concentrations of 3,3’,4,4’-Benzophenonetetracarboxylic dianhydride at test start were in the range of 95 to 99 % and after 72 hours in the range of 98 to 106 % of the nominal values. Therefore, all effect values are based on the nominal concentrations of the test item 3,3’,4,4’-Benzophenonetetracarboxylic dianhydride.

NOEC, LOEC, EC - values and Confidence Intervals of 3,3’,4,4’-Benzophenonetetracarboxylic dianhydride (0 -72 hours) based on nominal test item concentrations [mg/L]


Growth Rate Inhibition



NOEC (pH-neutralized)





45.6 (25.0 – 50.0)


68.6 (50.0 – 100)