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Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
21 April 2009 - 10 June 2009
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The test was judged valid since the measured results fulfilled the validity criteria. The test was conducted according to OECD 301C.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report Date:
2009

Materials and methods

Test guidelineopen allclose all
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
Deviations:
no
Qualifier:
according to
Guideline:
other: Test Method Relating to New Chemical Stubstances (Yakushokuhatsu No. 1121002, Heisei 15.11.13 Seikyoku No. 2, Kanpokihatsu No. 031121004)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): SX-1
- Chemical Name: 7,7'(8H,8'H)-Spirobi[1H,6H-dibenzo[b,g][1,9,4,6]dioxadiazacyclododecine],1,1',15,15'-tetradehydro-
- Physical state: white powder
- Analytical purity: 99.3
- Lot/batch No.: 902801
- Stability under test conditions: stable under storage conditions
- Storage condition of test material: airtight container in a desicator at room temperature

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge: Chemicals Evaluation and Research Institute, Japan
- Laboratory culture: mixed liquor suspended solids (3300 mg/L)
- Storage length: 5d
- Date of receipt: 16 April 2009
- Concentration of sludge: 30 mg/L
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimationopen allclose all
Parameter followed for biodegradation estimation:
O2 consumption
Parameter followed for biodegradation estimation:
test mat. analysis
Details on study design:
TEST CONDITIONS
- Stirring: Continuous with magnetic stirrer
- Test volume: 300mL
- Test temperature: 25+/-1
- pH: 7.0-8.0 in all flasks throughout the test period
- pH adjusted: no

TEST SYSTEM
- Number of culture flasks/concentration: Bottle 1: Activated sludge + basal medium + analine (100mg/L)
Bottle 2: Activated sludge + basal medium
Bottle 3: Activated sludge + basal medium + test stubst (100mg/L)
Bottle 4: Activated sludge + basal medium + test stubst (100mg/L)
Bottle 5: Activated sludge + basal medium + test stubst (100mg/L)
Bottle 6: test stubst (100mg/L) + purified water (300mL)
- Measuring equipment: closed system oxygen consumption measuring apparatus (OM-3100A, Okura Electric Co. - ID Code: J)

SAMPLING
- Sampling frequency: BOD daily, DOC and residual amount of test substance at d28
Reference substance
Reference substance:
aniline

Results and discussion

% Degradationopen allclose all
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
28 d
Remarks on result:
other: calculated results for all replicates were negative, yielding an overall % degradation of 0
Parameter:
% degradation (test mat. analysis)
Value:
1
Sampling time:
28 d
Remarks on result:
other: based on residual test amount at day 28
Details on results:
The % degradation was calculated based on BOD (measured daily) and residual test substance (measured at day 28). The DOC was not used to calculate % degradation, as the test substance was barely soluable and the DOC in the abiotic control was less than 90% of the theoretical value.

BOD5 / COD results

Results with reference substance:
d7 BOD(mg) = 57.8, d14 BOD(mg) = 68.4, d21 BOD(mg) = 70.6, d28 BOD(mg) = 70.8

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
not inherently biodegradable
Conclusions:
From the degradability results based on the BOD (mean 0%) and the residual amount of the test substance (mean 1%), it is concluded that the test substance is not readily biodegradable. No transformation product was generated under the conditions of this test.
Executive summary:

A ready biodegradability test was performed for SX-1 according to the Japanese Test Method Relating to New Chemical Substances <Biodegradability Test of Chemical Substances by Microorganisms>, which is akin to OECD301C. The reference substance was analine, for which the degree of biodegradability at d14 (based on BOD) was greater than 60%. The difference of extremes of replicate values at d28 was less than 20%. The BOD in the blank (bottle 2) was less than 18mg O2 after 28 days. BOD (over 28 days), DOC (at d28) and residual test substance (at d28) were measured, though only BOD and residual test substance were used to calculate the biodegradation of SX-1. The degradability results were mean 0% and mean 1% based on BOD and residual test substance, respectively. Thus, SX-1 was judged not readily biodegradible.