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Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Biodegradation in water:

Estimation Programs Interface Suite (EPI suite, 2018) was run to predict the biodegradation potential of the test compound in the presence of mixed populations of environmental microorganisms. 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 chemical is expected to be not readily biodegradable.

Biodegradation in water and sediments:

Estimation Programs Interface (EPI Suite, 2018) prediction model was run to predict the half-life in water and sediment for the test compound . If released in to the environment, 6% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of test chemical in water is estimated to be 180 days (4320 hrs). The half-life (180 days estimated by EPI suite) indicates that the chemical is persistent in water and the exposure risk to aquatic animals is moderate to high whereas the half-life period of test chemical in sediment is estimated to be 1620.833 days (38900 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.000982%), indicates that test chemical is not persistent in sediment.

Biodegradation in soil:

The half-life period of test chemical in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2018). If released into the environment, 94% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical in soil is estimated to be 360 days (8640 hrs). Based on this half-life value of test chemical, it is concluded that the chemical is persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to high.

Additional information

Biodegradation in water:

Predicted data for the test chemical and supporting weight of evidence studies for its structurally similar read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In a prediction using the Estimation Programs Interface Suite (EPI suite, 2018), the biodegradation potential of the test chemical 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 test chemical is expected to be not readily biodegradable.

 

In a supporting weight of evidence study from peer reviewed journal (J. A. Buswell and Peter Jurtshuk, 1969) for test chemical biodegradation experiment was conducted for evaluating the percentage biodegradability of test chemical using resting cell suspension of Corynebacterium sp. as the test inoculum. Corynebacterium sp.(7EIC),was isolated from soil by conventional enrichment technique with propane as sole carbon. Medium L with n-octane as the sole carbon source (supplied in the vapour phase), was used for growth of the organism. For solid medium 2% (w/v) Difco Bacto-agar was added. Resting cell suspensions for polarographic investigations were obtained by growing cell batches, prepared by transferring a five-day slope culture to one-litre amounts of Medium L contained in 4-litre filtering flasks. The flasks were agitated on a reciprocal shaker at 30 ~ for four days. The cell mass was harvested after four days, washed, and resuspended in phosphate buffer. Exact test chemical conc. used for the study was not known, but a variable substrate concentration (saturating concentration that gave the maximal oxidation rate) was taken for the study. The final reaction mixture contained 0.02 M phosphate buffer (pH 7.0), 0.2 ml of resting cell suspension (0.78--2.60 mg dry wt), and a variable substrate concentration (saturating concentration that gave the maximal oxidation rate). The final reaction volume was 1.7 ml and the experiments were conducted at 30°C. All reactions were initiated by the addition of the hydrocarbon substrate. Substrate was added to the reaction vessel as an emulsion prepared by sonic oscillation (10 sec at full power with a Bronwill Sonifier) of 0.5 ml hydrocarbon with 10 ml of deionized H2O. Specific activities are reported as µl O2 consumed per hr per mg dry cell wt at 30°C. All specific activities were corrected by subtracting the endogenous respiratory rate, which ranged from 1.6 to 16.7 µl 02 per hr per mg dry wt of cells. Hydrocarbon oxidation was measured by oxygraphy using a YSI Clark oxygen electrode in conjunction with a Gilson Model KM Oxygraph. Specific activity for test chemical oxidation decreases because of a longer chain length. No activity was observed when test substance was supplied at low concentrations. The percentage degradation of test substance was determined to be 11%.Thus, based on percentage degradation, is considered to be not readily biodegradable in water.

 

Another biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of the same test chemical HSDB, 2017). Bacteria were used as a test inoculum isolated from Colgate Creek sediment. These bacteria were cultured in water obtained from both Colgate Creek and Eastern Bay in Chesapeake Bay, MD, respectively for 28 days at 20°C. The percentage degradation of test substance was determined to be 17-29% and 7-24% after 28 days. Thus, based on percentage degradation, test chemical is considered to be not readily biodegradable in nature.

 

Last study was reviewed from authoritative database (J-CHECK, 2017), biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test chemical. Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of test substance was determined to be 1 and 0% by BOD and HPLC parameter in 28 days. Thus, based on percentage degradation, test chemical is considered to be not readily biodegradable in nature.

 

On the basis of above results test chemical it is concluded that the test chemical is expected to be not readily biodegradable in nature.

Biodegradation in water and sediments:

Estimation Programs Interface (EPI Suite, 2018) prediction model was run to predict the half-life in water and sediment for the test compound . If released in to the environment, 6% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of test chemical in water is estimated to be 180 days (4320 hrs). The half-life (180 days estimated by EPI suite) indicates that the chemical is persistent in water and the exposure risk to aquatic animals is moderate to high whereas the half-life period of test chemical in sediment is estimated to be 1620.833 days (38900 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.000982%), indicates that test chemical is not persistent in sediment.

Biodegradation in soil:

The half-life period of test chemical in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2018). If released into the environment, 94% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical in soil is estimated to be 360 days (8640 hrs). Based on this half-life value of test chemical, it is concluded that the chemical is persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to high.