Esterification product of castor oil and tetrahydromethyl-1,3-isobenzofuranedione

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-08-23 - 2018-06-26

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation))

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: Ministry of environmental protection of the people's Republic of China, The Guidelines for the Testing of Chemicals-Effects on Biotic System, 2013, 209 Activated Sludge, Respiration Inhibition Test

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Esterification product of castor oil and tetrahydromethyl-1,3-isobenzofuranedione

EC Number:

700-064-6

Cas Number:

2105830-60-0

Molecular formula:

Not applicable as this is a UVCB substance

IUPAC Name:

Esterification product of castor oil and tetrahydromethyl-1,3-isobenzofuranedione

Test material form:

liquid

Details on test material:

- Molecular weight: 2800-3000
- CAS Name: Castor oil, polymer with tetrahydromethyl-1,3-isobenzofurandione
- Description: Very viscous amber liquid
- Test substance storage: At room temperature in the dark under nitrogen
- Stebility under storage conditions: Stable
- Expiry date: 01 January 2009

Specific details on test material used for the study:

Test Substance code: BLKN20170414-1787

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

activated sludge

Details on inoculum:

Sludge collection: a fresh sample of activated sludge for the range-finding was collected from the aeration stage of Longhua Living Wastewater Treatment Plant in Shanghai which treated predominantly domestic sewage on Nov 2nd, 2017. The sludge was areated till use.
Sludge treatment: On return to the laboratory the sludge was washed, with an isotonic solution containing 0.85% NaCl(w/v). After centrifuging the supernatant was decanted. This procedure was repeated three times (4000rpm, 4°C, centrifuge 20minutes). A small amount of the washed sludge was weighed and dried by moisture balance at 105°C for 1 h to calculate the dry weight. The dry weight of sludge used in range-finding test count up to 6.40% of the gross weight, respectively.
Sludge suspension: Calculate the amount of wet sludge needed to be suspended in isotonic solution based on the dry weight. Then place the wet sludge into certain amount of solution to obtain the required sludge solids concentration of 3g/L. Suspended with a mixer and areated till use. The final concentration of the activated sludge in the test medium is 1.5g/L.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Test conditions

pH:

7.00 - 7.22

pH
0h 3h
FB (mg/L) C1 7.03 7.06 6.85 2.04 6.17 46.77 31.18 -
C2 7.11 7.16 6.96 2.04 6.33 46.64 31.09 -
11 7.00 7.02 6.90 2.08 6.17 46.87 31 .25 -0.10
101 7.01 7.04 6.93 2.13 6.17 46.68 31 .12 0.32
FT (mg/L) 1001 7.18 7.15 6.87 2.06 6.17 46.77 31 .18 0.11
1001 7.18 7.16 6.95 2.01 6.33 46.82 31 .22 0.00
1001 7.22 7.21 6.80 2.01 6.17 46.58 31 .05 0.52
FA (mg/L) 1001 7.05 7.07 9.63 9.61 10.00 0.12 - -

FB = Blank; FT = Test substance; FA = Abiotic control

Dissolved oxygen:

dissolved oxygen
Upper limit Lower Limit Δt (min)
FB (mg/L) C1 6.85 2.04 6.17 46.77 31.18 -
C2 6.96 2.04 6.33 46.64 31.09 -
11 6.90 2.08 6.17 46.87 31 .25 -0.10
101 6.93 2.13 6.17 46.68 31 .12 0.32
FT (mg/L) 1001 6.87 2.06 6.17 46.77 31 .18 0.11
1001 6.95 2.01 6.33 46.82 31 .22 0.00
1001 6.80 2.01 6.17 46.58 31 .05 0.52
FA (mg/L) 1001 9.63 9.61 10.00 0.12 - -

Details on test conditions:

The solubility of test substance was less than 1 mg/L as described by the sponsor. The test substance was weighted and added directly into the test vessels.

Test substance group(FT):
The test substance was added directly together with 16ml synthetic sewage feed, well mixed, added ultra-pure water till 250ml and then mixed with 250ml activated sludge suspended solution. Finally, concentrations of 11 mg/L, 101 mg/L and 1001 mg/L (3 replicates were settled under this concentration) were obtained.

Blank control group(F8) :
16ml synthetic sewage feed with ultra-pure water added up to 250ml, then mixed with 250ml activated sludge suspended solution(2 replicates was settled).

Abiotic control(F A):
The test substance was added directly together with 16ml synthetic sewage feed, well mixed, then added ultra-pure water till 500ml, The final concentration was 1001 mg/L.

Reference substance (positive control):

yes

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

3 h

Dose descriptor:

IC0

Effect conc.:

>= 1 001 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Effect concentrations 2

Key result

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

>= 1 001 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

The Respiration inhibition percentage of the test substance on the respiration of activated sewage sludge were 0.11 %, 0.00% and 0.52% under the concentration of 1001 mg/L in the range-finding test. A t-Test indicated no significant differences between range-finding test group and blank control (p=0.874, p>0.05). There was no respiration inhibition effection of the test substance on the respiration of activated sewage sludge.
The definitive test was unnecessary.

Results with reference substance (positive control):

A solution of 0.10030g of 3,5-dichlorophenol in 100ml of water was prepared. Warm water was used to accelerate the dissolution and made the solution up to
volume when it had cooled to room temperature. The pH of the solution was 7.36 and adjustment was not needed.
Certain amount of reference substance stock solution was added together with 16ml synthetic sewage feed, well mixed, added ultra-pure water till 250ml and then mixed with 250ml activated sludge suspended solution. Finally, concentrations of 7.80mg/L, 12.60mg/L, 20.00mg/L and 32.00mg/L were obtained.
The respiration inhibition of 3h ECso of reference substance was 13.5mg/L, 95% confidence limit was 13.4~13.6mg/L.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The highest test concentration of 1001 mg/L of the test substance did not inhibit the respiration of activated sewage sludge.

Executive summary:

The highest test concentration of 1001 mg/L of the test substance did not inhibit the respiration of activated sewage sludge.