Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Currently viewing:

Administrative data

Endpoint:
biodegradation in water: inherent biodegradability
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Basic data given; comparable to guideline study; test was performed by an laboratory with an high reputation for delivery of solid data.

Data source

Referenceopen allclose all

Reference Type:
publication
Title:
Biodegradation and Bioconcentration of Existing Chemical Substances under the Chemical Substances Control Law - Naphthalene
Author:
NITE National Institute of Technology and Evaluation, Japan
Year:
1979
Bibliographic source:
http://www.safe.nite.go.jp/data/hazkizon/pk_e_kizon_disp.html?k_no=0058
Report Date:
1979
Reference Type:
publication
Title:
Biodegradation and bioaccumulation data of existing chemicals based on the CSCL Japan
Author:
Chemical Inspection & Testing Institute (CITI), Japan
Year:
1992
Bibliographic source:
published by Japan Chemical Industry Ecology-Toxicology & Information Center, October 1992
Report Date:
1992

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 302 C (Inherent Biodegradability: Modified MITI Test (II))
Principles of method if other than guideline:
MITI-II test performed under the auspices of the Japanese Chemical Inspection & Testing Institute (CITI); method is similar or according to later OECD TG 302C (MITI II Test)
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): naphthalene
- no further information on test material

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge: sludge was sampled and prepared according to Japanes standard procedure (samples taken from 10 different sites: 3 city sewage plants, 1 industrial sewage plant, 3 rivers and 3 bays; sampling 4 times every year)
- Laboratory culture: sludge was kept in culture for 3 month
- Method of cultivation: Sludge was cultured at 25 ± 2°C. On every day about 30 min after cessation of aeration, 1/3 of the supernatant was removed and replaced by an equal amount of dechlorinated water. Aeration was continued and synthetic sewage (5% w/v of glucose, peptone and monopotassium phosphate, pH adjusted to 7 ± 1 with sodium hydroxide) was added.
- Storage conditions: at 25 ± 2°C
- Storage length: 3 month
- Preparation of inoculum for exposure: measurement of concentration of suspended solid according to JIS K 0102 method 14.1
Duration of test (contact time):
4 wk
Initial test substance concentration
Initial conc.:
30 other: ppm
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS
- Composition of medium: 3 mL of solution A, B, and C as described in JIS K 0102 method 21 were made up to 1000 mL with purified water and the pH was adjusted to 7.0
- Test temperature: 25 ± 2
- pH: 7
- pH adjusted: if required
- Aeration of dilution water: no data
- Suspended solids concentration: 100 ppm
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: Close system oxygen consumption measuring apparatus; 300 mL glas vessels
- Number of culture flasks/concentration: 3 for test substance, 2 for test substance blanks, 1 for abiotic control, 1 for positive control
- Method used to create aerobic conditions: production of O2 as O2 was consumed.
- Measuring equipment: Coulometer Ohkura Electric Co., Ltd.
- Test performed in closed system: yes
- Details of trap for CO2 and volatile organics if used: soda lime No. 1 (extra pure reagent, Wako Pure Chemical Industries, Ltd.)
- Other: test solution was stirred by a magnetic stirrer

SAMPLING
- Sampling frequency: continuous registration of O2 consumption; test substance determination at the beginning and at the end of the test

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic control: yes
- Toxicity control: no

Results and discussion

% Degradationopen allclose all
Parameter:
% degradation (O2 consumption)
Value:
2
Sampling time:
4 wk
Parameter:
% degradation (test mat. analysis)
Value:
0
Sampling time:
4 wk

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
: criteria as required by MITI-II method
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
In a MITI-II test for inherent biodegradability similar to OECD TG 302C performed under the Japanese Chemical Inspection & Testing Institute, no biodegradation of the test substance naphtalene was observed.