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Environmental fate & pathways

Biodegradation in water: screening tests

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Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The authors tested the biodegradability of benzyl chloride according to the OECD guideline 301C. GLP standards are not specified and validity criteria are partially met. Thus the study should be considered a Klimisch 2c study as it is comparable to a guideline study with acceptable restrictions.

Data source

Reference
Reference Type:
publication
Title:
Biodegradation and bioaccumulation. Data of existing chemicals based on the CSCL Japan.
Author:
Ministry of International Trade and Industry
Year:
1992
Bibliographic source:
Japan Chemical INdustry Ecology-Toxicology & Information Center

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
Deviations:
no
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Benzyl chloride
No more data available
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
No data available

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure):
Locations:
sludge samples were taken at 10 places in Japan
Fukogawa city sewage plant (Sapporo-shi Hokkaido)
Fukashiba industry sewage plant (Kashima-gun Ibaragi)
Nakahama city sewage plant (Osaka-shi Osaka)
Ochiai city sewage plant (Shinjuku-ku Tokyo)
Kitakami river (Ishinomaki-shi Miyagi)
Shinano river (Nishikanbara-gun Niigata)
Yoshino river (Tokushima-shi Tokushima)
Lake Biwa (Otsu-shi Shiga)
Hiroshima bay (Hiroshima-shi Hiroshima)
Dookai bay (Kitakyushu-shi Fukuoka)

Sampling time:
March, June, September and December in every year

Sampling method:
Returned sludge of sewage was collected
For rivers, lake and sea the surface water and surface soil which were in contact with the atmosphere were collected

Mixing of fresh and old activated sludge:
5 L of the filtrate of the supernatant of an activated sludge in use was mixed with 500 mL of the filtrate of the supernatant of a newly collected sludge. The mixture was cultured at pH 7.0 +/- 1.0 under sufficient aeration (i.e. prefiltered open air was used)


- Laboratory culture:
About 30 minutes after ceasing the aeration to the sludge mixture, supernatant corresponding to about 1/3 of the whole volume was removed. Then an equal volume of dechlorination water was added to the remaining portion and aerated again. Afterwards synthetic sewage (i.e. glucose, peptone and monopotassium phosphate dissolved in dechlorination water, each with a 5% (W/V) concentration and adjustment of pH with sodium hydroxide to 7.0 +/- 1.0) was added so that the ratio was 0.1% (W/V). This procedure was repeated every day and the culturing was carried out at 25°C +/- 2°C.


- Preparation of inoculum for exposure:
The methodology for measuring the concentration of suspended solid was in accordance with Japanese Industrial Standards (JIS) K 0102-1986-14.1

Preparation of basal culture medium; each 3 mL of solution A, solution B, solution C and solution D (i.e. described in JIS K 0102-1986-21) were made up to 1000 mL with purified water after which the pH of the solution was adjusted to 7.0 pH.


- Concentration of sludge: 30 mg/L


No more data available
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS
- Test temperature: 25 +/- 1 °C
- Other:
Control of cultivation:
During cultivation, appearance of the supernatant, precipitability, formation of flock, pH and dissolved oxygen concentration in the solution as well as temperature were checked. When necessary adjustements were made. Microflora in the activated sludge was microscopically observed ans sludge with no normal symptom was used for the test.


TEST SYSTEM
- Culturing apparatus: Closed system oxygen consumption measuring apparatus (Coulometer: Ohkura Electric Co., Ltd.)
- Number of culture flasks/concentration: each test vessel contained 300 mL of basal culture medium containing a concentration of suspended solid of 30 mg/L or 100 mg/L into which 30 mg or 9 mg of the test substance was added
- Method used to create aerobic conditions: The absorbent for carbon dioxide was Soda lime n°1 (extra pure reagent, Wako Pure Chemical Industries, Ltd.)


CONTROL AND BLANK SYSTEM
- Inoculum blank: one inoculum blank was performed, the test vessel contained 300 mL of basal culture medium and the concentration of suspended solid reached to 30 mg/L or 100 mg/L
- Procedure control: a test vessel containing 300 mL of basal culture medium into which 30 mg of aniline (reference substabce) was added and the concentration of suspended solid reached to 30 mg/L or 100 mg/L
- Other: A test vessel containing 300 mL of purified water into which 30 or 9 mg of the tet substance was added.


No more data available
Reference substance
Reference substance:
aniline

Results and discussion

Preliminary study:
No data available
Test performance:
No data available
% Degradation
Parameter:
% degradation (O2 consumption)
Value:
71
Sampling time:
2 wk
Details on results:
Since the biodegradation of the substance had reached a plateau at day 14, the study was terminated before the intitially planned 28 days.

BOD5 / COD results

Results with reference substance:
The percentage of biodegradation of the reference substance was more than 40% and 60% at day 7 and 14 respectively.

Applicant's summary and conclusion

Validity criteria fulfilled:
not specified
Interpretation of results:
readily biodegradable
Conclusions:
Under the test conditions, 71% of benzyl chloride was degradated after 2 weeks in a OECD guidline 301C test. Thus the substance should be considered as readily biodegradable according to the EC regulation n°1272/2008 and the former 67/548/EC regulation.
Executive summary:

The authors tested the biodegradability of benzyl chloride (CAS n° 100 -44 -7 ) according to the OECD guideline 301C. They tested two concentrations but only one concentration is reported in the results. At 100 mg/L of benzyl chloride in the test medium, 71% of the test substance was biodegradated

after 14 days in the test conditions based on the biological demand in oxigen (BOD). Thus these elements show that benzyl chloride should be considered as readily biodegradable.

No data was available on the GLP procedure during this test. Besides few details on the results are available in this publication. Therefore, validity criteria are partially met for the percentage of biodegradation of the reference substance and the remaining criteria cannot be checked. However considering that the authors followed the OECD guideline 301C and the test was documented with sufficient details on the methodology, the study should be considered as reliable with restrictions and comparable to a guideline study with acceptable restrictions.