3,4-dimethoxyphenethylamine

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: screening tests

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification

Justification for type of information:

The supporting QMRF report has been attached

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

Principles of method if other than guideline:

The data is predicted using the OECD QSAR toolbox version 3.3 with logKow as the primary descriptor.

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of the test material (IUPAC name): 2-(3,4-dimethoxyphenyl)ethan-1-amine
- Common name: 3,4-dimethoxyphenethylamine
- Molecular weight: 181.2335 g/mole
- Molecular formula: C10H15NO2
- Smiles: COc1ccc(CCN)cc1OC
- Inchl: 1S/C10H15NO2/c1-12-9-4-3-8(5-6-11)7-10(9)13-2/h3-4,7H,5-6,11H2,1-2H3
- Substance type: Organic
- Physical state: Liquid

Oxygen conditions:

aerobic

Inoculum or test system:

other: Micro-organisms

Duration of test (contact time):

28 d

Based on:

not specified

Parameter followed for biodegradation estimation:

other: BOD

Key result

Parameter:

other: BOD

Value:

1.167

Sampling time:

28 d

Remarks on result:

other: Other details not known

Details on results:

Test substance undergoes 1.17% degradation by BOD in 28 days.

The prediction was based on dataset comprised from the following descriptors: BOD
Estimation method: Takes average value from the 6 nearest neighbours
Domain  logical expression:Result: In Domain

((((((((((("a" or "b" or "c" or "d" or "e" )  and "f" )  and "g" )  and "h" )  and "i" )  and "j" )  and "k" )  and "l" )  and "m" )  and "n" )  and ("o" and "p" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Primary amines by OECD HPV Chemical Categories

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Aliphatic Amines by US-EPA New Chemical Categories

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Michael addition AND Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals AND Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals >> Hydroquinones by DNA binding by OECD

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Narcotic Amine by Acute aquatic toxicity MOA by OASIS

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Aliphatic Amines by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as days - weeks by Biodeg primary (Biowin 4) ONLY

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as weeks - months by Biodeg ultimate (Biowin 3) ONLY

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Not calculated by Hydrolysis half-life (pH 6.5-7.4) ONLY

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Class 5 (Not possible to classify according to these rules) by Acute aquatic toxicity classification by Verhaar (Modified) ONLY

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Bioavailable by Lipinski Rule Oasis ONLY

Domain logical expression index: "k"

Similarity boundary:Target: COc1ccc(CCN)cc1OC
Threshold=30%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Aliphatic Amine, primary AND Aryl AND Ether by Organic Functional groups ONLY

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as Aliphatic Amine, primary AND Aryl AND Ether by Organic Functional groups ONLY

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Aliphatic Amine, primary AND Aryl AND Ether by Organic Functional groups ONLY

Domain logical expression index: "o"

Parametric boundary:The target chemical should have a value of Molecular weight which is >= 112 Da

Domain logical expression index: "p"

Parametric boundary:The target chemical should have a value of Molecular weight which is <= 236 Da

Validity criteria fulfilled:

not specified

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The test chemical 2-(3,4-dimethoxyphenyl)ethan-1-amine was estimated to be not readily biodegradable in water.

Executive summary:

Biodegradability of 2-(3,4-dimethoxyphenyl)ethan-1-amine (CAS no. 120 -20 -7) is predicted using QSAR toolbox version 3.3 with logKow as the primary descriptor. Test substance undergoes 1.17% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 2-(3,4-dimethoxyphenyl)ethan-1-amine was estimated to be not readily biodegradable in water.

Description of key information

Biodegradability of 2-(3,4-dimethoxyphenyl)ethan-1-amine (CAS no. 120 -20 -7) is predicted using QSAR toolbox version 3.3 (2018) with logKow as the primary descriptor. Test substance undergoes 1.17% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 2-(3,4-dimethoxyphenyl)ethan-1-amine was estimated to be not readily biodegradable in water.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

Various predicted data for the target compound 2-(3,4-dimethoxyphenyl)ethan-1-amine (CAS No. 120-20-7) and supporting weight of evidence studies for its functionally similar read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In a prediction done by SSS (2018) using OECD QSAR toolbox version 3.3 with logKow as the primary descriptor, percentage biodegradability of test chemical 2-(3,4 -dimethoxyphenyl)ethan-1 -amine (CAS No. 120 -20 -7) was estimated.Test substance undergoes 1.16% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 2 -(3,4 -dimethoxyphenyl)ethan-1 -amine was estimated to be not readily biodegradable in water.

 

In another prediction using the Estimation Programs Interface Suite (EPI suite, 2018), the biodegradation potential of the test compound2-(3,4-dimethoxyphenyl)ethan-1-amine(CAS No. 120-20-7) in the presence of mixed populations of environmental microorganisms was estimated.The biodegradability of the substance was calculated using seven different models such as Linear Model, Non-Linear Model, Ultimate Biodegradation Timeframe, Primary Biodegradation Timeframe, MITI Linear Model, MITI Non-Linear Model and Anaerobic Model (called as Biowin 1-7, respectively) of the BIOWIN v4.10 software. The results indicate that chemical2-(3,4-dimethoxyphenyl)ethan-1-amineis expected to be not readily biodegradable.

 

In a supporting weight of evidence study from peer reviewed journal (Stefan Gartiser, et. al; 2007) for the read across chemical Trimethoprim (CAS no. 738-70-5),biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of read across substance Trimethoprim (CAS no. 738-70-5). The study was performed according to combination of OECD 301 B (CO2 evolution test) and OECD 302 B (Zahn-Wellens test, respectively under aerobic conditions. Activated sludge derived from the municipal sewage treatment plant of Whyl (Abwasserzweckverband Kaiserstuhl Nord, population equivalent 14.300) was used as a test inoculum for the study. The activated sludge was used immediately and washed twice with mineral medium according to OECD 302 B. Conc. of test inoculum and intial test substance conc. used for the study was0.2 gm d.s./l and 100 mg/l based on TOC, respectively. Mineral medium mentioned in OECD 302 B guideline was used as a test medium for the study.20 gas wash bottles (2000 ml volume each) with lateral connecting pieces with butyl rubber septums for DOC sampling were used as reactors. Test vessels were aerated with CO2-free air for 24 hrs during 28 day period. The liquid volume was fixed at 1.500 ml each. Mixing was performed by a magnetic stirrer with 2 cm stir bars. In addition to the test vessel, at least two inoculum blanks, two reference bottles with sodium benzoate as a procedure control and in some tests one inhibition control with the test and the reference compound were prepared. Sodium benzoate was used as a reference substance for the study. The CO2-free air production system consisted of an air compressor (NO10.AN 18, KNF Neuberger, Freiburg, Germany), two 1000 ml gas wash bottles filled with dry soda lime, followed by three bottles, one filled with 0.1 M NaOH (sodium hydroxide), one filled with 0.05 M Ba(OH)2 (barium hydroxide) and one filled with demineralised water. The CO2-free air was passed on to an air distributer with two input and 20 output channels and through PE-tubes to the sealed reactors at a rate of 50–100 ml/min each. The CO2 produced in the reactors was absorbed in two 250 ml gas wash bottles in series, each filled with 200 ml 0.2 M NaOH. Herein the second CO2-absorber flask was used as a protective flask to shield the first one from room air. Unlike the original test guideline of the CO2-evolution test sampling was performed without changing the absorption bottles. NaOH (4 ml) was removed through the butyl rubber septum using 5 ml PE syringes in order to avoid CO2 influx from room air to the system. The amount withdrawn for sampling was considered in the calculation of degradation. On the 28th day (exception: the screening assay was prolonged up to 36 d) 1 ml concentrated hydrogen chloride acid (HCl) was added into each reactor to release the CO2 dissolved in water and the IC (IC = inorganic carbon) was determined in both CO2-absorber flasks in line. The amount of carbon dioxide produced from the test compound less the amount derived from the blank inoculum was expressed as a percentage of ThCO2 (theoretical amount of CO2) introduced with the test compound. The DOC was determined from 10 ml samples withdrawn from the reactors through butyl rubber septum after filtration with cellulose acetate 0.45lm filters. Both IC and DOC measurements were performed using total carbon analyser (TOC-5000 A, Shimadzu Deutschland, Duisburg). DOC-elimination was calculated from the DOC in the respective test flask less the mean DOC in blanks in relation to the TOC introduced with the test compound. Reference substance sodium benzoate undergoes 60-83% degradation in 7 days. The percentage degradation of test substance Trimethoprim was determined to be 23 and 16% by TOC and DOC removal parameter in 0.125 days and 28 days, respectively. Thus, based on percentage degradation, Trimethoprim is considered to be not readily biodegradable in nature.

 

Another biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of the same read across substance Trimethoprim (CAS no. 738-70-5) (Gsbl database, 2017). The study was performed according to OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test) under aerobic conditions at a temperature of 20°C, respectively. Mixed culture was used as a test inoculum obtained from sewage treatment plant, drain. Sodium acetate was used as a reference substance for the study. Test substance conc. used in the study was 0.0046 to 3.25 mg/l, respectively. The percentage degradation of test substance Trimethoprim was determined to be 4% by O2 consumption parameter in 28 days. Thus, based on percentage degradation, Trimethoprim is considered to be not readily biodegradable in nature.

 

On the basis of above results for target chemical 2-(3,4-dimethoxyphenyl)ethan-1-amine(from OECD QSAR toolbox version 3.3 and EPI suite, 2018) and for its read across substance (from peer reviewed journal and authoritative database Gsbl), it can be concluded that the test substance 2-(3,4-dimethoxyphenyl)ethan-1-amine can be expected to be not readily biodegradable in nature.