D-Gluconic acid, δ-lactone, reaction products with propanolamine

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

June 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Test Item Name FiberHance BM Solution
CAS Index Name D-Gluconic acid, δ-lactone, reaction products with propanolamine
CAS Number 2060570-71-8
Molecular Formula C9O7NH19
Molecular Weight 253
Batch/Lot Number SMSN-071916
Analysed Purity 49.71% (Refer Certificate of Analysis in APPENDIX 5)
Manufactured by Not Provided
Supplied to JRF by Ashland Services B.V.
Date of Manufacture July 19, 2016
Date of Expiry July 19, 2017
Appearance/Color Colorless, Odorless clear liquid
Other Characteristics pH : 5.2
Water solubility 100% soluble
Storage Condition
(at JRF) As per the instruction received from the Sponsor on storage of the test item, the test item was stored :
Storage Temperature : Room Temperature
Storage Container: In original container as supplied by the Sponsor
Storage Location : Test Item Control Office, JRF

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

Blank Control (BC1): At ‘0’ time, a volume of 234 mL water was poured in one liter bottle followed by 16 mL synthetic sewage feed and mixed thoroughly. Then a volume of 250 mL microbial inoculum was added and kept under constant aeration for 3 hours.
Reference substance: 2.5 mL reference substance stock solution (section 2.10.1) in 200 mL water followed by 16 mL of synthetic sewage and balance with water to make the total volume 250 mL. Finally, 250 mL of inoculum was added to obtain a reference substance concentration of 5.0 mg/L in two replicates. Other reference substance concentrations viz., 15.01 and 30.02 mg/L were prepared in the same manner by addition of 7.5 and 15.0 mL of reference substance stock solution at an interval of 15 minutes.
Test Mixture (TM): A volume 0f 0.5 mL test item stock solution (section 2.10.2) was transferred in 150 mL water followed by 16 mL of synthetic sewage and balance with water to make the total volume of 250 mL. Finally, 250 mL of inoculum was added to obtain a dissolved solid fraction (49.71%)test item concentration of 10.0 mg/L in two replicates. Other dissolved solid fraction test item concentrations viz., 100.02 and 1000.21 mg/L were prepared in the same manner by addition of 5.0 and 50 mL of test item stock solution at an interval of 15 minutes. The highest concentration of dissolved solid fraction test item (1000.21 mg/L) was prepared in three replicates.
Abiotic Control (AC): was prepared in three replicates at highest concentration (1000.17 mg/L) by addition of the test item stock solution (section 2.10.3) in sterilized water and synthetic sewage but without microbial inoculum.
Nitrification Control (NC): was prepared same way as Blank Control, but with addition of 2.5 mL N-allylthiourea (section 2.10.4) stock solution to obtain final concentration of 11.6 mg/L.
Final volume was 500 mL for all above prepared samples and the pH was measured with pre-calibrated pH meter before addition of inoculum.

Test organisms (species):

activated sludge

Details on inoculum:

A quantity of four litres of activated sludge was collected from near the exit of the aeration tank of a well-operated waste water treatment plant receiving predominantly domestic sewage of Kashyap Sweeteners Pvt. Ltd., Vapi. India. The Coarse particles was removed by settling for a short period e.g., 5 to 15 minutes and the upper layer of finer solids was decanted for use. The activated sludge was continuously aerated (e.g., 2 L/minute) at the test temperature with addition of the synthetic sewage feed (50 mL synthetic sewage feed/L activated sludge) for use on next day. The activated sludge concentration was nominally 1.5 g/L of suspended solids in all tests, reference and blank (but not abiotic control) mixtures.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Test temperature:

20-24 ºC

pH:

7.4-7.7

Details on test conditions:

The whole system was kept under aeration for 3 hour at 20 ± 2 ºC. After 3 h contact time, the content of each bottle was transferred to the respective pre-labelled BOD bottle fitted with a magnetic stirrer. The respiration rate was measured using dissolved oxygen (DO) meter over a period of ten minutes. The pH was also measured at the same time. The measurements were continued at a 15-minutes interval in such a way that constant time of 3 hour in each sample was maintained. The electrode was rinsed with water between each measurement.

Reference substance (positive control):

yes

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Remarks:

Reaction mass of 3-hydroxypropan-1-aminium D-gluconate and N-(3-hydroxypropyl)-D-gluconamide

Basis for effect:

inhibition of total respiration

Results with reference substance (positive control):

EC50 Value (mg/L): 4.49 mg/L

Validity criteria fulfilled:

yes

Conclusions:

The concentration which cause a 50% reduction respiration rate in activated sludge (EC50) was estimated to be >2000 mg FiberHance BM Solution/L corresponding with a dissolved solid fraction of 1000 mg/L. The No Observed Effect Concentration (NOEC) after 3 hour exposure was 1000 mg/L based on the dissolved solid fraction in FiberHance BM Solution.

Description of key information

The No Observed Effect Concentration (NOEC) after 3 hour exposure was 1000 mg/L based on the dissolved solid fraction  in FiberHance BM Solution.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

1 000 mg/L

Additional information

The concentration which cause a 50% reduction respiration rate in activated sludge (EC50) was estimated to be >2000 mg FiberHance BM Solution/L corresponding with a dissolved solid fraction of 1000 mg/L.