Leuco polysulfided 4-[(2,4-dinitrophenyl)amino]phenol

Endpoint summary

Description of key information

The test item was not readily biodegradable under the conditions of the performed 28 Day Closed Bottle Test according to OECD Guideline 301 D.

Additional information

The test item was investigated for its ready biodegradability in a closed bottle test over 28 days based on the OECD Guideline for Testing of Chemicals No  301 D (1992). The test item was exposed to activated sludge from the aeration tank of a domestic waste water treatment plant. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. The chosen test item concentration of 3.0 mg/L investigated in the main test was based on the results of the preliminary solubility and toxicity tests. The chemical oxygen demand (COD) of 1.743 mg O2/ mg test item was determined at the start of the main experiment. Under the test conditions not readily biodegradation of the test item was not noticed, the percentage biodegradation of the test item reached a mean of 8.8 % after 28 days based on its COD. The concurrently conducted analytical determination of a possible nitrite and nitrate development demonstrated that no nitrification occurred, therefore the biodegradability value of the test item was calculated based on its COD. The reference item Sodium benzoate was sufficiently degraded to a mean of 79.0 % after 14 days, and to a mean of 88.7 % after 28 days of incubation, based on ThODNH3, thus confirming the suitability of the used activated sludge inoculum. In the toxicity control containing both, the test item and the reference item, a mean of 42.9 % biodegradation was noted within 14 days and 46.6 % biodegradation after 28 days of incubation. Thus, the test item can be assumed to inhibit the activated sludge microorganisms (less than 25 % degradation occurred within 14 days).