2,4,6-trichloroaniline

Endpoint summary

Description of key information

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.

Additional information

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.