2,2,4-trimethylpentane-1,3-diol

Biodegradation in water and sediment: simulation tests

Administrative data

Endpoint:

biodegradation in water: sewage treatment simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study conducted under GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

other:

Principles of method if other than guideline:

The procedure described in this test method is based on the Soap and Detergent Association's "A Procedure and Standards for the Determination of Biodegradability of Alkyl Benzene Sulfonate and Linear Alkylate Sulfonate." The Association's method is limited to the determination of primary removability because of its reliance on a specific analytical method. By measuring soluble carbon, the method utilized for this study is expanded to measure ultimate removability because the fate of the entire organic molecule is followed. In addition, the method can be extended to test substances for which there are no analytical methods.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2,2,4-trimethylpentane-1,3-diol

EC Number:

205-619-1

EC Name:

2,2,4-trimethylpentane-1,3-diol

Cas Number:

144-19-4

Molecular formula:

C8H18O2

IUPAC Name:

2,2,4-trimethylpentane-1,3-diol

Details on test material:

- Name of test material (as cited in study report): SS0426.01 (2,2,4-trimethylpentanediol or TMPD)
- Percent active: >98%
- Solubility in water: >1000 mg/L
- Storage condition of test material: room temperature

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, adapted

Details on inoculum:

The activated sludge used to initiate the study was obtained from a municipal treatment plant receiving predominantly domestic waste; Downingtown Regional Water Pollution Control Center in Downingtown, Pennsylvania.

Duration of test (contact time):

7 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

20 mg/L

Based on:

act. ingr.

Initial test substance concentration 2

Initial conc.:

13.68 mg/L

Based on:

other: soluble organic carbon

Parameter followed for biodegradation estimation:

other: soluble organic carbon

Details on study design:

TEST SET-UP: The test apparatus consisted of four SCAS aeration chambers each containing 1.5 L of the activated sludge. Two units were needed for the test subsubstance and two units were required as controls. The sludge was screened through a 2 mm sieve to remove large clumps. The total suspended solids (TSS) level was determined to be 4,627 mg/L. Based on this reading the sludge was distributed among the SCAS units such that when the volume in each unit was diluted to 1.5 L with tap water the suspended solids level was ~2,500 mg/L. The units were set up the same day the activated sludge was collected from the treatment plant.

SLUDGE ACCLIMATION PERIOD: The units were aerated for 23 1/2 hours (±1/2 hr.) at a rate adequate to maintain solids suspension. At the end of this period, the air was turned off and the sludge was allowed to settie for ~30 minutes. One liter of effluent was drawn off and replaced with one liter
of influent consisting of 10 mL synthetic sewage and 990 mL tap water to bring the volume back to 1.5 liters. The air was turned on and this process was repeated on a daily basis for ~ 9 days. Twenty milliliters of synthetic sewage was added to each unit on the first two days of the sludge acclimation period to help maintain suspended soilds at ~ 2,500 mg/L.

TEST SUBSTANCE ACCLIMATION PERIOD: On the day addition of the test substances was to begin, the sludge was settled, composited, and redistributed among the units so that each unit contained a uniform sample of sludge. Two of the SCAS units were dosed with each test substance for a 7-day acclimation period. This consisted of incremental additions until the final test concentration of 20 mg active/L was reached. On the first day the appropriate quantity of test substance was added to the SCAS test units to bring the concentration in the influent to 20% of the final concentration. This addition was increased by 20% on a daily basis for four days. The units were fed the final test concentration of 20 mg active/L tor two additional days. During the test substance acclimation period all units, including the control units, were fed 10 mL synthetic sewage and sufficient tap water to bring the final volume to 1.5 L. Daily effluents were discarded.

TESTING PERIOD: The fourth feeding of the final test concentration began the testing period. One liter of effluent was withdrawn daily from each unit and saved for analysis. The effluent was replaced with a comparable volume of influent as described above. An aliquot of each effluent sample was centrifuged. A subsample of the centrate was acidified with concentrated H2S04, purged with N2, and submitted for SOC analysis.

TREATMENT OF RESULTS: For each day of the test, the percent(%) carbon remaining in solution was calculated by subtracting the average carbon in the control units (blanks) from the carbon in the test unit. This number was divided by the amount of test substance carbon added (based on the average measured initial TOC) and multiplied by 100. The percent removal was calculated by subtracting the percent remaining from 100.

Results and discussion

% Degradation

% Degr.:

101

Parameter:

other: soluble organic carbon removal

Sampling time:

1 d

Remarks on result:

other: Mean of 7 daily measurements. 95% CL = 99.4-102.6%

Transformation products:

not measured

Details on results:

For the two control (blank) units, an analysis of variance (ANOVA) was perfomed on the carbon data to ascertain whether there was any significant difference between the two replicates. At a 1% test level it was concluded that there was no significant difference betweent he controls. For the test substance units an additional analysis of variance (ANOVA) was perfomed on the % removals to determine if the replicates were significantly different. If they were not, an overall average removal was computed for the test substance. At a 1% test level it was determined that there was no significant difference between the two test units and the average % removal is calulated to be 101% with a 95% confidence interval of 1.6%.

Any other information on results incl. tables

Table 1: Soluble Organic Carbon and Percent Removal Data

Test Day	Control A (mg C/L)	Control B (mg C/L)	Control Mean (mg C/L)	Test Substance A (mg C/L)	Test Substance A % Removal	Test Substance B (mg C/L)	Test Substance B % Removal
1	4.4	4.4	4.4	3.9	103.7	4.3	100.7
2	4.2	4.5	4.4	3.9	103.7	4.5	99.3
3	4.7	4.6	4.7	4.1	104.4	4.6	100.7
4	4.6	5.0	4.8	5.8	92.7	5.0	98.5
5	4.4	5.8	5.1	5.2	99.3	5.5	97.1
6	4.9	5.6	5.3	4.5	105.8	4.4	106.6
7	4.8	5.4	5.1	4.5	104.4	4.4	105.1

Applicant's summary and conclusion

Executive summary:

A Semi-Continuous Activated Sludge (SCAS) Removability Test was conducted on 2,2,4-trimethylpentanediol (TMPD). This test is designed to determine the removability of the test substances in the SCAS test system, as measured by soluble organic carbon (SOC). The test apparatus consisted of four SCAS aeration chambers containing 1.5 L of activated sludge obtained from a domestic wastewater treatment plant. The suspended solids level in each unit was adjusted to ~2,500 mg/L. The units were aerated at a rate adequate to maintain solids suspension. Following a sludge acclimation period (stabilization), the test substance was dosed incrementally to duplicate SCAS units for a 7-day test substance acclimation period. The final nominal test substance concentration was 20 mg active/L. Following the acclimation period, and with the fourth feeding of the final test concentration, the 7 day testing period began. One liter of effluent was withdrawn daily from each unit and saved for soluble organic carbon analysis (SOC). The effluent was replaced with a comparable volume of fresh influent containing the test substance and synthetic sewage and the process was repeated each day. Two additional units were treated in the same manner but did not receive test substance and served as controls. During the 7 day testing period SOC was measured in samples removed from the control and test substance replicates. For each day of the test, the percent (%) carbon remaining in solution was calculated by subtracting the average carbon in the control units (blanks) from the carbon in the test unit. This number was divided by the amount of test substance carbon added (based on the average measured initial TOC) and multiplied by 100. The percent removal was calculated by subtracting the percent remaining from 100. The results of these daily analyses over the 7 day testing period was a mean removal of 101% with a 95% confidence interval of ± 1.6%.