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Environmental fate & pathways

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Description of key information

Biodegradtion in water:

The test chemical 4-{bis[4-(dimethylamino)phenyl]methylidene}-N,N-dimethylcyclohexa-2,5-dien-1-iminium chloride ( CAS no. 548 -62 -9) showed 3.6 % biodegradation by using parameter CO2 evolution in 28 days. By this percent biodegrdation value this chemical is considered as not readily biodegradable.

Biodegradtion in water and sediments:

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound N-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chloride (CAS No: 548 -62 -9) .If released in to the environment, 2.22 % of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of the chemical N-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chloride in water is estimated to be 60 days (1440 hrs). The half-life (60 days estimated by EPI suite) indicates that the chemical is persistent in water and the exposure risk to aquatic animals is high whereas the half-life period of N-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chloride in sediment is estimated to be 541 days (13000 hrs) indicates that test chemicalN-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chlorideis persistent in sediment as well.

Biodegradtion in Soil:

The half-life period ofN-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chloride(CAS No: 548 -62 -9) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2017). If released into the environment, 48.8 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemicalN-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chloridein soil is estimated to be 120 days (2880 hrs). Based on this half-life value of test chemicalN-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chloride, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to low.

Additional information

Biodegradtion in water:

Results of different experimental studies and predicted data studies of target chemical 4-{bis[4-(dimethylamino)phenyl]methylidene}-N,N-dimethylcyclohexa-2,5-dien-1-iminium chloride ( CAS no. 548 -62 -9) and results of experimental studies for its closest read across chemicals with log Kow as primary descriptor were reviewed as follow.

 

In a experimental study done by Clariant Chemical (India) limited in 2010. The test chemical 4-{bis[4-(dimethylamino)phenyl]methylidene}-N,N-dimethylcyclohexa-2,5-dien-1-iminium chloride (CAS no. 548-62-9) showed 3.6 % biodegradation by using parameter CO2 evolution in 28 days. By this percent biodegradation value this chemical is considered as not readily biodegradable.

 

In another study done by Chiing-Chang Chen , Hung-Ju Liao, Chiu-Yu Cheng , Chia-Yuen Yen and Ying-Chien Chung published in journal Biotechnology letters in 2007 biodegradation experiment was performed to test biodegradability of test chemical (4-(4,4'-Bis(dimethylamino)benzhydrylidene)cyclohexa-2,5-dien-1-ylidene)dimethylammonium chloride (CAS no. 548-62-9) by taking bacteria pseudomonas putidaas a inoculum isolated from waste water of dye manufacturing company at concentration of 6×107cfu/mL. Prior to the experiment, the bacterial cells were pre-cultivated in nutrient broth for 12 h. The initial concentration of test chemical taken was 0.022 mg/L and pH was 7.5 and temperature was 37 o C. After 7 days amount of residual chemical was analysed by using HPLC and percent biodegradation was calculated. Percent Biodegradation of test chemical (4-(4,4'-Bis(dimethylamino)benzhydrylidene)cyclohexa-2,5-dien-1-ylidene)dimethylammonium, chloride obtained was 78.5 % by test material analysis parameter. By percent biodegradation this test chemical is considered as readily biodegradable by pseudomonas putida.

 

In next study prediction was done to check biodegradability of test chemical N-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chloride ( CAS no. 548-62-9) using OECD QSAR tool box v.3.3 using log kow as primary descriptor. The biodegradation percentage of test chemical N-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chloride obtained was only 3 %  by considering BOD parameter  and microorganisms as inoculum in 28 days. By considering this value of percent biodegradability it is concluded that test chemical N-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chloride is not readily biodegradable.

 

Another prediction done by using Estimation Programs Interface Suite (EPI suite, 2017)to predict the biodegradation potential of the target chemical N-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminiumchloride(CAS No: 548-62-9) 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 the chemicalN-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chloride is not readily biodegradable.

 

In a supporting weight of evidence study done for read across chemical 4-[4 (dimethylamino)benzenecarboximidoyl]-N,N-dimethylaniline hydrochloride (CAS no. 2465-27-2) biodegradation potential was determined by taking sludge as inoculums at 30 mg/L concentration. Biodegradation was analyzed by using BOD and UV-vis parameter. The initial concentration of read cross chemical was 100 mg/L and study design is of standard type. After 2 weeks (14 days) test chemical 4-[4-(dimethylamino)benzenecarboximidoyl]-N,N-dimethylaniline hydrochloride showed 0% biodegradation by BOD and 12% by UV-vis parameter so it is concluded that test chemical 4-[4-(dimethylamino)benzenecarboximidoyl]-N,N-dimethylaniline hydrochloride is not readily biodegradable.

 

In another supporting weight of evidence study done for another read across chemical benzyl(triphenyl)phosphanium chloride (CAS no.1100-88-5)biodegradation test was carried out by taking sludge as inoculums at 30 mg/L concentration and O2 consumption (BOD), TOC removal and test material analysis by HPLC as parameters. The initial concentration of read cross chemical was 100 mg/L and by taking standard test equipment. After 4 weeks (28 days) read across chemical benzyl(triphenyl)phosphanium chloride showed 0% biodegradation by all three parameters in 28 days. So it is concluded that this read across chemical is not readily biodegradable.

 

By considering all the results of above mentioned study of target chemical 4-{bis[4-(dimethylamino)phenyl]methylidene}-N,N-dimethylcyclohexa-2,5-dien-1-iminium chloride (CAS no. 548-62-9) and supporting weight of evidence study of its read across chemicals percentage of biodegradation was very low ( below 20 %) therefore it is concluded that this test chemical not readily biodegradable but in one study of target chemical published in Biotechnology letters journal shows contradicting results i.e., target chemical readily biodegradable as its degradation percentage was very high ( 78.5%) in 7 days by bacteria pseudomonas putida the probable reason for this result is that the target chemical shows cytotoxicity to many microorganisms as reported by Michaels and Lewis (1986) and gram negative bacteria Pseudomonas putida is resistance to many antibiotics and chemical hence it is able to degrade it.

However in environment there are many type of microorganisms which not resistance to target chemical which shows cytotoxicity to many organisms. Hence by considering results of other above mentioned studies and studies of read across chemicals it is concluded that target chemical 4-{bis[4-(dimethylamino)phenyl]methylidene}-N,N-dimethylcyclohexa-2,5-dien-1-iminium chloride (CAS no. 548-62-9) is expected to be not readily biodegradable.

Biodegradtion in water and sediments:

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound N-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chloride (CAS No: 548 -62 -9) .If released in to the environment, 2.22 % of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of the chemical N-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chloride in water is estimated to be 60 days (1440 hrs). The half-life (60 days estimated by EPI suite) indicates that the chemical is persistent in water and the exposure risk to aquatic animals is high whereas the half-life period of N-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chloride in sediment is estimated to be 541 days (13000 hrs) indicates that test chemicalN-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chlorideis persistent in sediment as well.

Biodegradtion in Soil:

The half-life period ofN-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chloride(CAS No: 548 -62 -9) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2017). If released into the environment, 48.8 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemicalN-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chloridein soil is estimated to be 120 days (2880 hrs). Based on this half-life value of test chemicalN-(4-{bis[4-(dimethylamino)phenyl]methylene}cyclohexa-2,5-dien-1-ylidene)-N-methylmethanaminium chloride, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to low.