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Environmental fate & pathways

Endpoint summary

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Description of key information

Stabiity:

Hydrolysis:

2, 4, 6 Trichloroaniline is stable over a period of 2 weeks under ambient conditions in the absence of light. Therefore it can be concluded that half life of hydrolysis of test chemical 2,4,6-trichloroaniline is > 12 days. This half life of hydrolysis value indicates thet test chemical in not hydrolysable.

Biodegradation:

Biodegradation in water:

The test chemical 2,4,6-trichloroaniline undergoes 2.57 % biodegradation after 28 days in the test condition. Thus, the test chemical can be considered as not readily biodegradable.

Biodegradation in water and sediments:

Test filter experiments were carried out by circulating water through a glass column (diameter: 42mm, height:90 mm) filled with pumice .The experiments were carried out in darkness at a temperature of 20oC in aerobic conditions. After filling of columns with pumice, unfiltered water from the river Elbe was circulated for a minimum of one month, and replaced by fresh river water every week. During the following experiments the water was replaced with filtered river water (glass fibre filter of 0.5mm) every 6 to 8 days. The decrease in the volume of water due to sampling was corrected for by calculating relative contact times in the filter. For each test filter, experiments were conducted on a control sample which was un-pumped and maintained in an open bottle under the same conditions. The samples were analysed by using HPLC/DAD (DAD L- 4500, Merck) using a C-18-column (ABZ+Plus, Supelco). The half life test compound 2, 4, 6 trichloroaniline is observed to be 19 hrs and the mean biodegradation rate constant was 0.036/h. On the basis of this half life value it can be concluded that test chemical is not persistent in river water with sediments.

Bioaccumulation:

Biaccumulation: aquatic/sediments:

The bioconcentration factor (BCF) for chemical 2,4,6-trichloroaniline was determined according static fish test. The BCF value was observed to 27-112 L/kg at dose concentration 0.1 mg/L and 52-147 L/kg at dose concentration 0.01 mg/L on test organism Cyprinus carpio during 8 weeks period. On the basis of BCF values it is concluded that test chemical 2,4,6-trichloroaniline is non bioaccumulative.

Transport and distribution:

Additional information

Stabiity:

Hydrolysis:

The half life of hydrolysis of test chemical was determined by performing an experiment in this the three aqueous solutions of 2,4,6-trichloroaniline (30 mg/L) were separately buffered to pH 5, 7, and 9 (10- M acetate, phosphate and borate respectively) and stored in stoppered volumetric flasks in the dark at room temperature.

Ultraviolet scans on the day of preparation and at intervals of 1 and 2 weeks showed no significant changes.

This indicates that 2,4,6-TCA in water is not hydrolyzed over a 2-week period under ambient conditions in the absence of light andhalf life of hydrolysis of test chemical 2,4,6-trichloroaniline is > 12 days.

Biodegradation:

Biodegradation in water:

Various experimental studies were reviewed from experimental report and different journals to determine biodegradability of test chemical 2,4,6-trichloroaniline in water and their results are summarized below.

 

The first experimental study was reviewed from experimental report in this study the 28-days Manometric respirometry test following the OECD guideline 301F was performed to determine the ready biodegradability of the test chemical 2,4,6-trichloroaniline . The study was performed at a temperature of 20± 1°C. Mixture of domestic waste water, surface soil and soil samples was used as a test inoculum for the study. This inoculum was collected and was mixed to get diluted suspension. The inoculum was kept aerobic until being used for experiment by supplying organic and inorganic sources required by micro flora to sustain at controlled laboratory conditions.  This gave the bacterial count 107 to 108 CFU/ml. At the regular interval microbial plating was also performed on agar to confirm the vitality and CFU count of microorganism. OECD mineral medium was used for the study. The test system included control, test item and reference item. The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 100 mg/L, while that of inoculum was 10 ml/L . ThOD (Theoretical oxygen demand) of test and reference item was determined by calculation. % Degradation was calculated using the values of BOD and ThOD for test item and reference item. The % degradation of procedure control (Sodium Benzoate) was also calculated using BOD & ThOD and was determined to be 75.20%. The mean BOD value (mg O2/l) in control on 28th day was 15.8mg O2/l, thereby fulfilling the control validity criteria (i.e., the oxygen consumption of the inoculum blank is normally 20-30 mg O2/l and should not be greater than 60 mg/l in 28 days). Degradation of Sodium Benzoate exceeds 65.65 %after 7 days and 69.79 % after 14 days. The activity of the inoculums is thus verified and the test can be considered as valid. The BOD28 value of test chemical 2,4,6-trichloroanilinewas observed to be 0.023 mgO2sup>/mg. ThOD was calculated as 0.896 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to manometric respirometry test was determined to be 2.57 %. Based on the results, the test item, under the test conditions, was considered to be not readily biodegradable at 20 ± 1°C over a period of 28 days.

 

Next study was reviewed from Journal of Environmental Science and Health (1984) in this study Microbial degradation of test chemical 2,4,6-trichloroaniline (CAS no. 634-93-5) was conducted with water samples from which sediments were removed by settling and filtration and it is obtained from canal creek. Canal Creek is a small stream at the Aberdeen Proving Ground, MD, the sediments of which were believed to be contaminated with2,4,6-trichloroaniline.Cotton-stoppered 500 mL Erlenmeyer flasks containing 200 mL of sample water were buffered (0.2% potassium phosphate, 0.01% ammonium sulfate, pH 7.0) and incubated with 3 mg/L2,4,6-trichloroanilinein a final volume of 250 mL. Incubation was carried out in the dark for 6 weeks at 25°C with constant agitation. Aliquots of samples were removed throughout the incubation period for chemical analysis as described below or for bacterial enumeration by triplicate plating on Standard Methods Agar (SMA). Controls consisted of identical flasks containing water samples which had been autoclaved for 15minutes prior to the addition of the t e s t chemical and buffer. Parameter used for biodegradability was test material analysis by GC. More than 65 % percent degradation obtained in both control and test flask till 30 days and test chemical was 100% (beyond detection limit) in 35 days. Since degradation obtained in both control and test flask it cannot be clearly interpreted that test chemical is biodegradable or not but after 30 days test chemical is degraded beyond detection limit. On the basis of percent degradability in control as well as in test flask it can be interpreted that test chemical is not readily biodegradable.

 

Another experimental study was reviewed from authoritative database (J check, 2018) in this study the Biodegradation experiment was carried out of test chemical 2,4,6-trichloroaniline (CAS no. 634-93-5) by taking activated sludge as inoculums at 30 mg/L concentration for 28 days. Biodegradation was analyzed by using two parameters namely BOD and HPLC. The initial concentration of test chemical was 100 mg/L. After 28 days of incubation percent biodegradation of test chemical 2,4,6-trichloroaniline was observed to be 0.0 % by BOD parameter 3.0 % by GC parameter. Therefore it is concluded that test chemical 2,4,6-trichloroaniline is not readily biodegradable.

 

Last experimental study was reviewed from chemosphere journal (1985) in this study the percent biodegradation of test chemical 2,4,6-trichloroaniline (CAS no. 634-93-5) was determined by using activated sludge as inoculums. The activated sludge was obtained from municipal sewage treatment plant and it is adapted to a synthetic nutrient medium for easy handling and standardization, CO2 evolution was used as parameter. The percent biodegradation of test chemical 2,4,6-trichloroaniline was determined to be 0.4 % .On the basis of percent degradation value it can be concluded that test chemical is not readily biodegradable in nature.

 

 By considering results of all the studies mentioned above it can be concluded that test chemical 2,4,6-trichloroaniline (CAS no. 634-93-5) is not readily biodegradable in water.

Biodegradation in water and sediments:

Two different experimental studies were reviewed from different journals to determine half life of degradation of test chemical in water as well as sediments results of both the studies are summarized below.

 

The first study was reviewed from Water Research Journal (2001)in this study the Test filter experiments were carried out by circulating water through a glass column (diameter: 42mm, height:90 mm) filled with pumice .The experiments were carried out in darkness at a temperature of 20oC in aerobic conditions. After filling of columns with pumice, unfiltered water from the river Elbe was circulated for a minimum of one month, and replaced by fresh river water every week. During the following experiments the water was replaced with filtered river water (glass fibre filter of 0.5mm) every 6 to 8 days. The decrease in the volume of water due to sampling was corrected for by calculating relative contact times in the filter. For each test filter, experiments were conducted on a control sample which was un-pumped and maintained in an open bottle under the same conditions. The samples were analysed by using HPLC/DAD (DAD L- 4500, Merck) using a C-18-column (ABZ+Plus, Supelco). The half life test compound 2, 4, 6 trichloroaniline is observed to be 19 hrs and the mean biodegradation rate constant was 0.036/h. On the basis of this half life value it can be concluded that test chemical is not persistent in river water with sediments.

 

Next experimental study was reviewed from journal Environmental Toxicology and Chemistry (1992) in this study an experiment was performed to determine half life of degradation of test chemical 2,4,6-trichloroaniline in anaerobic condition in this experiment the Sediment-water slurries were collected from Loosdrechtse Plassen eutrophic pond and slow-moving streams in The Netherlands in this organic carbon content was 33% and pH was 6.5 . The characteristic parameters of the sediment-water systems are given below. Samples were taken by scraping off the top 5 to 10 cm of the sediment and collecting it in glass jars. The jars were completely filled with a mixture of sediment and water and closed below the water surface with an aluminum screw-cap containing a rubber stopper. The jars were incubated for at least one week before substrate addition to ensure anaerobic conditions.

The rate constant of the initial transformation process obtained was -5.47 per minutes. The half life of test substance 2, 4, 6-trichloroaniline observed was 143 days under water-sediment system in anaerobic condition, indicating that the substance is persistent in water-sediment system.

On the basis of result of first study the half life of degradation of test chemical 2, 4, 6 trichloroaniline is observed to be 19 hrs in aerobic condition and in another study it was 143 days this higher number of days is may be because study was performed in anaerobic condition. By considering half life value in aerobic condition it can be concluded that test chemical is not persistent.

Bioaccumulation:

Biaccumulation: aquatic/sediments:

Various experimental studies have been reviewed from different sources for test chemical 2,4,6-trichloroaniline (CAS no 634-93-5) and their results are summarized below for bioaccumulation in aquatic organisms endpoint.

 

The first experimental study was reviewed from authoritative database (J check, 2018) in this study the Bioaccumulation experiment was conducted for 8 weeks for determination the bioconcentration factor (BCF) of chemical 2,4,6-trichloroaniline (CAS no 634-93-5) on test organism Cyprinus carpio.

The recover ratio used was for test water: 1st concentration area: 88.1 %, 2nd concentration area: 85.0 %, Fish : 92.0 %, and Limit of detection : Test water

1st concentration area: 0.0057 mg/L, 2nd concentration area: 0.00059 mg/L, Fish: 0.04 mg/L. The vehicle used in the study was HCO-20.

Nominal concentrations used in the study are 1st Concentration area: 0. 1 mg/L, 2nd Concentration area: 0.01 mg/L and Range finding study was carried out on Rice fish (Oryzias latipes) TLm(48h) 8.2 ppm(w/v), Thus the bioconcentration factor (BCF) for chemical 2,4,6-trichloroaniline was determined according static fish test. The BCF value was observed to 27-112 L/kg at dose concentration 0.1 mg/L and 52-147 L/kg at dose concentration 0.01 mg/L on the basis of total lipid content on test organism Cyprinus carpio during 8 weeks period. On the basis of BCF values it is concluded that test chemical 2,4,6-trichloroanilineis non bioaccumulative.

 

 Next experiment study was done by Freitag et al (1985) and it is reviewed from journal Chemospher in this study the Bioaccumulation factor of test chemical 2,4,6-trichloroaniline (CAs no. 634-93-5) was determined in fish golden ide (Leuciscus idus melanotus)and it was selected as representative of inhabitants of slightly polluted zones of running water. It represents an intermediate position between trout and carp. Bioconcentration is measured by using the average constant exposition to the chemicals dissolved in water. Bioaccumulation factor of test chemical 2,4,6-trichloroaniline (CAs no. 634-93-5) was determined 330 dimensionless in 3 days. On the basis of BCF value it can be concluded that test chemical is non-bioaccumulative in nature since BCF value does not exceeds 2000 criteria of CLP regulation.

 

Last experimental study was done by W. D .Wolf et al (1993) from journal Archives of Environmental Contamination and Toxicology in this study an experiment was performed to determine Bioaccumulation factor (BCF) of test chemical 2,4,6-trichloroaniline in fish Poecilia reticulate (guppy) for 96 hrs in this experiment guppies (n = 12) were exposed to the test chemical in a static exposure system, where the chemical was dissolved by continuous stirring in autoclaved Cu2+-free Utrecht tap water 4 days prior to the start of experiments. These solutions were further diluted with autoclaved water to obtain the desired exposure concentration. After acclimation to autoclaved water for four days, guppies were exposed in 0.5 L test vessels for 96 h under continuous and gentle aeration with sterile air and the initial concentration of test chemical was 500 nM, the temperature was 23.5 oC, pH of water was between 7-8 and dissolved oxygen concentration of test water was 7 mg/L . Water samples were taken in triplicate every 24 h in order to follow the concentrations of parent compounds. At the end of the experiment, 250 ml of water sample was extracted and were analyzed for possible biotransformation products by gas chromatography with electron capture detection (GC-ECD) and mass spectrometry (GC-MS) (operated in methane/negative ion chemical ionization.

On the basis of analysis the bioaccumulation factor (BCF) of test chemical 2,4,6-trichloroaniline determined to be 1621.81, 199.52 dimensionless on the basis of lipid content and whole body weight respectively. Further, the Uptake rate constant (k1) determined was 68±3 (ww) and 366 ± 63 (lipid) (mt g-1 h-l) and Depuration (loss) rate constant (k2) determined was 0.029 ± 0.007 (h- 1) in fish Poecilia reticulate (guppy) in 96 hrs.

By considering BCF values it is concluded that test chemical 2,4,6-trichloroaniline is non bioaccumulative in nature as the BCF value does not exceed the 2000 criteria of GLP regulation.

 On the basis of results of all the studies mentioned above it is observed that Bioaccumulation factor(BCF) of test chemical 2,4,6-trichloroaniline is in range from 27.00 to 1621.81 dimensionless. By considering this range BCF value it can be concluded that test chemical in non bioaccumulative in nature.

Transport and distribution:

Adsorption/desorption:

Various experimental studies from different journals and experimental report have been reviewed for adsorption and desorption endpoint of test chemical2,4,6-trichloroaniline(CAS No.634-93-5).

 

The first study was experimental report (2015) in this study the adsorption coefficient (Log Koc) on soil and on sewage of 2,4,6-trichloroaniline (CAS No.634-93-5) was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. The reference substances were chosen according to estimated Kocrange of the test substance and generalized calibration graph was prepared. The reference substances were 4 chloroaniline, 4 methylaniline, N methylaniline, 2 Nitrophenol, Nitrobenzene, 4-Nitrobenzamide, N,N-dimethylbenzamide, N-methylbenzamide, Benzamide, phenanthrene having Kocvalue ranging from 1.239 to 4.09.

The Log Kocvalue was determined to be 3.466± 0.004 at 25°C temperature.

By considering log Koc value it can be concluded that test chemical has moderate sorption to soil and sediment and therefore has slow migration potential to ground water.

 

 

Next study was reviewed from journal Environmental Pollution (2005) in this study the Batch experiments have been performed in order to evaluate the ability of the two reference clays kaolinite (KGa-1) and Na montmorillonite (SWy-1) to retain 2, 4, 6-trichloroaniline. 100 mL of solutions of test chemical 2,4,6-trichloroaniline was put in contact under constant agitation with 2.0 g of, respectively kaolinite and Na-montmorillonite. The experiments have been performed at four concentration levels (1.0, 2.5, 5.0 and 10.0 mg/L) in a pH range between 5.0 and 5.5 for kaolinite and between 8.8 and 9.3 for Na montmorillonite.

The Kd (L g-1) value for the test substance 2, 4, 6- trichloroaniline were determined to be 0.0389 and 0.0488 for kaolinite (KGa-1) and Na montmorillonite (SWy-1) clays respectively. The test chemical 2, 4, 6- trichloroaniline is sorbed by clay standard kaolinite and Na-montmorillonite at different extents and likely by different mechanisms. The test chemical 2,4,6-trichloroaniline showed 8 % adsorption on clay standard kaolinite at all four concentrations of test chemicals (10, 5, 2.5 and 1.0 mg/L) , 10 % adsorption on clay Na-montmorillonite at 10 and 5 mg/L concentrations.X-ray analysis suggests that the 2, 4, 6 trichloroaniline investigated is preferentially sorbed on mineral surface on kaolinite, while when sorption on montmorillonite is considered, a progressive swelling of the structure can be observed, due to sorption processes that also take place in the interlayer, as shown by the study carried out on the dehydrated Na-montmorillonite system.

 On the basis of percent adsorbed it can be concluded that test chemical 2, 4, 6- trichloroaniline has low sorption on clay standard kaolinite and Na-montmorillonite.

 

Another experimental study was reviewed from Environmental Science and Pollution Research journal (2006) in this study the sorption experiments were carried out by immersing 2.00 g of clay mineral namely kaolinite KGa-1 and montmorillonite in 100.0 mL of test chemical solutions at concentrations of 10.0, 50.0, 100.0 and 200.0 mg/L. Experiments with kaolinite KGa-1 were carried outat both pH 4.8 (the natural pH of kaolinite in water) and at pH 9.9 (to compare the sorption results with those of montmorillonite). The systems were electromagnetically stirred for at least 1 week and, at regular intervals, 500μLof the suspension were collected, centrifuged (4500 rpm, 6 minutes), filtered(0.45μm) and analysed by HPLC analysis to deduce the amount of test chemical retained.

For the desorption experiments, suspensions resulting from the sorption experiments were centrifuged (4500 rpm, 10 minutes), and the solid phase containing the sorbed test chemical was air-dried and then submerged in ultra pure water at the same solid/liquid ratio as in the sorption experiments (2.00 g/100.0 mL) The new system was stirred electromagnetically for 7 days and then 500μL of the suspension were collected, filtered and injected into the HPLC system for direct determination of the desorbed fraction.The substance 2, 4, 6-trichloronailine was strongly retained, with sorption of up to 8 mg/g, by the soil clays kaolinite KGa-1 and Na montmorillonite SWy-1. In desorption experiments, 2,4,6-trichloroaniline was the least desorbed from montmorillonite irreversibly retained on kaolinite.

For sorption on kaolinite (KGa-1),equilibrium is achieved in less than four days 2, 4, 6-trichloroaniline is sorbed (from an initial concentration of 200.0 mg/L) at a rate of 7.3 mg per gram of mineral clay, comparable with that sorbed by montmorillonite. The desorption experiments carried out on the adsorbed kaolinite for the 2, 4, 6-trichloroaniline reveal no significant desorption, at least as detected by the HPLC method. This suggests that the test chemical and the clay mineral form irreversible interactions, capable of resisting the desorption strength of simulated leaching.

 

 

Last experimental study was reviewed from chemosphere journal (2008) in this study the sorption experiments are carried out in triplicate by putting in batch conditions 2.00 g of the sorbing material in 100.00 mL of test material aqueous solution at concentration 200.00 mg/L. The systems are electromagnetically stirred for a total time of 15 days, 1.00 mL of the surnatant is collected, centrifuged (4500 rpm, 6 min), filtered on 0.20 µm polypropylene membrane (VWR International, West Chester, PA, USA) and submitted to HPLC analysis for the determination of the amount of test chemical still present in solution. From the amount initially present the quantity retained is calculated and expressed as mg of test chemical retained in batch conditions by 1.00 g of sorbent material.

To evaluate the amount of test chemical desorbed by the different leaching agents, the suspension obtained after 15 d of contact is centrifuged (4500 rpm, 10 min) and the solid phase (that contains the pollutant sorbed) is air-dried, weighed and submerged in the leaching solution in the same solid/liquid ratio as in the sorption experiments (2.00 g/100.00 mL). The new system is electromagnetically stirred for 15 d and then 1.00 mL of the supernatant is collected, filtered and injected into the HPLC system for the direct determination of the desorbed fraction of the test chemical. All the experiments are performed in triplicate.

The test chemical 2,4,6-trichloroaniline adsorbed on clay Na-montmorrilonite (SWy-2) were 10.0 ± 0.6 and 3.1 ± 0.7 mg/g , on clay kaolinite (KGa-1b) 7.3 ± 0.9 and 5.5 ± 1.3 mg/g and on clay BCR_-700 10.0 ± 1.5 and 3.3 ± 0.4 mg/g of clay.

Further, the test chemical desorbed from all three types of clays was < 0.1 %.

Thus on the basis of adsorption values on all three types of clays it can be conclude that test chemical 2,4,6-trichloroaniline shows capability to adsorb on different types of clays.

 

By considering results of all the studies mentioned above it can be concluded that test chemical 2,4,6-trichloroaniline(CAS No.634-93-5) shows moderate to low sorption to different types of clays and soil.