3,4-dichlorophenyl isocyanate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

November 26th, 2004 - April 19th, 2005

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: MITI (I), OECD TG 301 C)

GLP compliance:

yes

Specific details on test material used for the study:

purity: 98.9% (GC); Impurities remaining: 1.1%, unknown; The test substance was treated as 100% pure.

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure):

(1) Place: The sludge was collected from the following 10 locations throughout Japan:
Fushikogawa Treatment Plant (Sapporo City, Hokkaido)
Nakahama Treatment Plant (Osaka City, Osaka Prefecture)
Kitakami River (Ishinomaki City, Miyagi Prefecture)
Yoshino River (Tokushima City, Tokushima Prefecture)
Hiroshima Bay (Hiroshima City, Hiroshima Prefecture)
Fukashiba Treatment Plant (Kashima-gun, Ibaraki Prefecture)
Ochiai Treatment Plant (Shinjuku-ku, Tokyo)
Shinano River (Niigata City, Niigata Prefecture)
Lake Biwa (Otsu City, Shiga Prefecture)
Dokai Bay (Kitakyushu City, Fukuoka Prefecture)

(2) Time: September 2004

(3) Collection method:
- Returned sludge from sewage treatment plants
- Surface water of rivers, lakes, marshes and the sea, and topsoil at the edge of waves in contact with the atmosphere

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Remarks:

Determination of biochemical oxygen consumption (BOD) using a closed system oxygen consumption analyzer

Parameter followed for biodegradation estimation:

test mat. analysis

Remarks:

Quantitative analysis of the test substance by high performance liquid chromatography (HPLC)

Details on study design:

TEST CONDITIONS
- The concentration of suspended solids in the activated sludge was 4480mg/L.
- Test temperature: 25±1℃
- pH: The pH was adjusted to 7.0±1.0 and exposed to air in a culture tank.
- pH adjusted: yes
- Concentration of activated sludge: 30mg/L (as suspended solids concentration)
- Volume of test solution: 300mL

TEST SYSTEM
- Culturing apparatus: Closed system oxygen consumption measurement device (Constant temperature chamber and measuring unit made by Asahi Techneion, )

Preparation of test solutions
Six test vessels were prepared and the test solutions were prepared in the following way:
- Number of culture flasks/concentration: Six test containers (300 mL culture bottle, activated
sludge concentration 30 mg/L)
- Stirring method: rotating stirring by magnetic stirrer
- Preparation of basic culture medium: The following test solutions a)-d) were prepared. The test
solutions b), c), and d) were inoculated with activated sludge to achieve a suspended solid
concentration of 30 mg/L by diluting with purified water and adjusting the pH to 7.0.
a) (water + test substance) system (1 vessel, # 4): 300 mL of purified water was added to the
test container, and the concentration of the test substance was set to 100 mg/L (accurately
weighed using an electronic analytical balance).
b) (sludge + test substance) system (3 test vessels, # 1,2,3): The test solution containing 100
mg/L test substance (accurately weighed using an electronic analytical balance) and
activated sludge was placed in a test vessel (300 mL total volume, subtract the amount of
activated sludge added (2.01ml) from the 300ml of basic culture medium in the test vessel.)
c) (sludge + aniline) (1 vessel, # 5): The test solution containing 100 mg/L aniline (29.5 μL
(30mg, density= 1.022 g/cm3) of aniline are added by a micro syringe) and activated sludge
was placed in a test vessel (300 mL total volume, subtract the amount of activated sludge
added (2.01ml) from the 300ml of basic culture medium in the test vessel.).
d) The sludge blank system (1 vessel, # 6) contained activated sludge without test substance
in a test vessel (300 mL total volume, subtract the amount of activated sludge added
(2.01ml) from the 300ml of basic culture medium in the test vessel.)

Reference substance:

aniline

Remarks:

To confirm that the sludge was sufficiently active, aniline (Showa Chemical Co., Ltd. reagent special grade lot number S0-32360) was used as a control substance.

Key result

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

The substance formed 3,4-dichlororaniline (monitored and quantified by HPLC-UV) and 1,3-bis(3,4-dichlorophenyl) urea (detected by HPLC-MS).

Validity criteria fulfilled:

yes

Remarks:

Deviation: The difference between the maximum and minimum values of 100%, 100% and 57% for the percent reduction of test substance (HPLC) was not less than 20%. Justification see above

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

3,4-Dichlorophenyl isocyanate showed 0% degradation, relating to BOD, after 28 days (MITI, 2005).

Executive summary:

In a test, performed according to the OECD TG 301 C (Ready Biodegradability: MITI-I), 3,4-dichlorophenyl isocyanate showed 0% degradation, relating to BOD, after 28 days (MITI, 2005). Therefore, 3,4 -dichlorophenyl isocyanate is considered to be "not readily biodegradable".

Description of key information

In a test, performed according to the OECD TG 301 C (Ready Biodegradability: MITI-I), 3,4-dichlorophenyl isocyanate showed 0% degradation, relating to BOD, after 28 days (MITI, 2005). Therefore, 3,4 -dichlorophenyl isocyanate is considered to be "not readily biodegradable".

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater