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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

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Reference
Endpoint:
biodegradation in water: sewage treatment simulation testing
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
1991
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study (non-GLP), some but no major deficiencies, plausible result
Reason / purpose:
reference to same study
Qualifier:
according to
Guideline:
OECD Guideline 303 A (Simulation Test - Aerobic Sewage Treatment. A: Activated Sludge Units)
GLP compliance:
no
Radiolabelling:
no
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): activated sludge collected from a treatment works receiving predominantly domestic sewage (sewage treatment plant Niederrad)
Duration of test (contact time):
48 d
Initial conc.:
1 other: L/h
Based on:
test mat.
Initial conc.:
5 - 20 mg/L
Based on:
other: Carbon
Parameter followed for biodegradation estimation:
DOC removal
Details on study design:
TEST CONDITIONS
- Composition of medium: synthetic wastewater with nutrient solutions according to OECD Guideline

TEST SYSTEM
- Culturing apparatus: OECD confirmatory test apparatus
- Number of culture flasks/concentration: 1
% Degr.:
96.2
St. dev.:
2.55
Parameter:
DOC removal
Sampling time:
34 d
Transformation products:
not measured
Conclusions:
A biological degradation of 96.2 +/- 2,55 % was reached after the initial 14-day equlilibration period, where increasing amounts of test item were added to the test system.
Executive summary:

The ultimate biodegradability of Sulfonic acids, C13-17-sec-alkane, sodium salts was assessed in the aerobic sewege treatment simulation test using activated sludge units (OECD 303A). After the intial 14 -day equilibration period, where increasing amounts of test item were added to the test system, a degradation of 96.2 +/- 2.55 % was achieved throughout the study period, as determined by daily DOC measurements over 34 days.

These results indicate that Sulfonic acids, C13-17-sec-alkane, sodium salts can be regarded as well biodegradable under conditions of the test.

Description of key information

BIODEGRADATION IN SEWAGE TREATMENT PLANT SIMULATION TEST

For the registration substance a STP Simulation test OECD 303A is not available. Therefore the results from such a test for the structurally similar substance SAS (Secondary Alkane Sulfonate, CAS No. 97489 -15 -1, already REACH registered) is used. The test system was adapted for 14d and then valuated until Day 34. A degradation of 96.2 +/- 2.6 % was achieved in the valuation phase. In STP Monitoring studies for SAS (see IUCLID Chapter 5.5.1) a total removal of > 99.9% was measured. Degradation and removal of SAS may be used for the STP distribution model Simpletreet for the registration substance (see IUCLID Chapter 5.5). It is proposed to use as mass balance in the STP as a reasonable worst case: Effluent: 1%, Sludge 0.5 % (calculated by EUSES), Degradation 98.5%.

Key value for chemical safety assessment

Additional information