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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Toxicity to microorganisms

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Administrative data

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Description of key information

The toxicity of DTPA to microorganisms was assessed in several studies, including OECD 209 activated sludge respiration inhibition tests, and several biodegradation screening tests. In the activated sludge respiration inhibition study the 3-hour EC50 was greater than 1280 mg/L for DTPA-FeHNa, corresponding to 1340 DTPAFeNa2. A NOEC was established at 400 mg/L DTPA acid, corresponding to 498 mg/L DTPA-FeNa2.

Key value for chemical safety assessment

Additional information

In an OECD 209 test, a 3 -hour EC50 value could not be determined for DTPA-FeHNa, since only minor effects were observed at 1280 mg/L, the highest concentration tested. This was confirmed by DTPA acid in another OECD 209 test. In an OECD 302B inherent biodegradation test, no inhibition of activated sludge inoculum was observed at 100 mg/L DTPA acid (125 mg/L DTPA-FeNa2). In batch biodegradation studies using microbial inocula from pulp mill activated sludge, municipal activated sludge, and soil, no microbial inhibition was reported for DTPA acid concentrations of 400 mg/L (498 mg/L DTPA-FeNa2). Using pulp mill activated sludge pre-exposed to DTPA, no inhibition was reported in reaction mixtures containing 725 mg/L DTPA acid (904 mg/L DTPA-FeNa2). These results are consistent with the structurally similar compound EDTA, where EDTA did not significantly inhibit the respiration of activated sludge in an OECD 209 test up to a nominal concentration of 500 mg/L (EC20, EC50, EC80 >500 mg/L).