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Biodegradation in water: screening tests

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Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
5 October 1990 to 28 February 1991
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
The study is not considered relevant for this inorganic substance.
Qualifier:
according to guideline
Guideline:
other: Japanese biodegradability test of chemical substances in "Test Methods of New Chemical Substances", MHW and MITI, dated September 13, 1974.
GLP compliance:
yes
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
- Source: Standard activated sludge from Chemical Biotesting Center, Chemical Inspection & Testing Institute on January 17, 1991.
- Method of cultivation: One-third of the total supernatant was displaced with 0.1% synthetic sewage (according to JIS K0102), which was used for the culture.
- Concentration of sludge: 3550 mg/L (reported as 3550 ppm).
- Preparation of inoculum for exposure: With basal culture medium, 900 mg/L solution was prepared, 10 mL of which was added to the test solution.
Duration of test (contact time):
14 d
Initial conc.:
100 mg/L
Based on:
test mat.
Remarks:
reported as 100 ppm
Parameter followed for biodegradation estimation:
O2 consumption
Remarks:
not possible as the substance is inorganic
Parameter followed for biodegradation estimation:
test mat. analysis
Remarks:
Mg and Al
Details on study design:
TEST CONDITIONS
- Composition of medium: "basal culture medium" according to JIS K 0102.21(1). Composition not specified.
- Test volume: 300 mL
- Concentration of sludge: 30 mg/L
- Test temperature: 25±2 °C
- pH: 7.0±1.0.
- pH adjusted: test medium was adjusted to 7.0
- Other: dissolved oxygen: ≥5 mg/L

TEST SYSTEM
- Culturing apparatus: Closed system oxygen consumption measuring apparatus (Ohkura Electric Co., Ltd.). "Coulometer OM-2000"
- Number of culture flasks/concentration: 3

SAMPLING
- Sampling frequency: after 7 days and 14 days inoculation


CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: yes ("water")
- Toxicity control: no
Reference substance:
aniline
Parameter:
% degradation (test mat. analysis)
Value:
0
Sampling time:
28 d
Details on results:
After 14 days, 98.5% Al and 101.5% Mg were recovered over the three vessels.
In the abiotic water vessel, 92.2 % Mg and 103.4% Al were recovered after 14 days. The results indicate that almost all of the test substance was retained and not degraded by the sludge.
Please see the results tables in attached background material.
Results with reference substance:
Points of degradation plot (reference substance):
68.9 % degradation after 7 d
73 % degradation after 14 d
Validity criteria fulfilled:
not specified
Remarks:
the reference substance degraded for 69% after 7 days, showing that the activated sludge was sufficiently active.
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
The degradation of the substance was determined in the presence of standard activated sludge in accordance with Japanese Guidelines for a period of 14 days.
The degradation from the oxygen consumption was not possible for this inorganic substance. After 14 days, direct analysis was performed by analysis of Al and Mg in the solvent extracts.
Respectively 98.5% and 101.5% of original magnesium and aluminum were recovered based on the mean of 3 vessels. In the abiotic water vessel, 92.2 % Mg and 103.4% Al were recovered after 14 days. The results indicate that almost all of the test substance was retained and not degraded by the sludge (0% degradation).
Endpoint:
biodegradation in water: ready biodegradability
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
the study does not need to be conducted because the substance is inorganic

Description of key information

Even though a biodegradation study is not required, a study is available.

The degradation of the substance was determined in the presence of standard activated sludge in accordance with Japanese Guidelines for a period of 14 days.

The degradation from the oxygen consumption was not possible for this inorganic substance. After 14 days, direct analysis was performed by analysis of Al and Mg in the solvent extracts.

Respectively 98.5% and 101.5% of original magnesium and aluminum were recovered based on the mean of 3 vessels. In the abiotic water vessel, 92.2 % Mg and 103.4% Al were recovered after 14 days. The results indicate that almost all of the test substance was retained and not degraded by the sludge (0% degradation).

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed
Type of water:
freshwater

Additional information