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Hydrolysis

The Hydrolysis rate constant of Benzenamine, 4-methoxy- (p-Anisidine)is estimated to be 0.0000000000939446 cm3/molecule-sec at half-life of 1.366hrs. The estimated half-life of the substance indicates that the substance Benzenamine, 4-methoxy- (p-Anisidine) is rapidly hydrolysable.

 

Biodegradation in water: screening tests

A number of studies for the test compound Benzenamine, 4-methoxy- (p-Anisidine) (CAS no 104-94-9) were reviewed for the biodegradation end point which are summarized as below:

 

Study of Biodegradation in water (J check) was conducted for the test compound Benzenamine, 4-methoxy- (p-Anisidine) (CAS no 104-94-9). In assessment of the Ready Biodegradability of the substance 4-methoxyaniline ,the result for degradation was found to be 65.3%, 88% and100% after 2 weeks, based on BOD, TOC and GC parameter respectively. This value indicates that the substance 4-methoxyaniline is readily biodegradable in water.

 

Biodegradability test was performed (D Brown ICI PLC, P Laboureur from NTRL report) for p-anisidine under the OECD Guideline methods 301A (modified AFNOR) and 301E (modified OECD Screening Test). Six laboratories took part. For all laboratories the inoculum was final effluent from sewage and for one laboratory they used activated sludge. Test substance concentration was specified as a standard 20 mg/L DOC (dissolved organic carbon). Aniline was the reference substance. An identical test design/was specified for both the 301A and 301E methods with the inoculum control, and 4 test substances each being run in duplicate in identical shake flasks i.e. as well as the ,"glucose control" the “sterile control" and "Inhibitory action control”. The days for analysis were 0, 3, 7, 14, 21 and 28 and analysis by both DOC and by specific analysis. For p-anisidine laboratories B, C and D all found good degradation under 301A conditions, but essentially no degradation 301E conditions. Laboratories A, F and E (series II) both found p-anisidine to be readily degradable under 301E conditions as 301A, but it should be noted that laboratory E was using 20 x the prescribed inoculum level for 301E in its series II tests. The work described shows the "ready biodegradability" of p-anisidine according to the OECD 301A and OECD 301 A.

 

In another study of target chemical Benzenamine, 4-methoxy- (p-Anisidine) (D Brown ICI PLC, P Laboureur, 1983), Dyestuffs containing the azo chromophore form one of the major classes of synthetic dyestuffs, and include dyes from all application classes. Although such dyes, by their required function, cannot be expected to be readily biodegradable under aerobic conditions, they are decolourised under anaerobic conditions. This decolourisation being thought to proceed by reductive cleavage of the azo link to give aromatic amines. Thus, in a consideration of what environmental risk may be associated with losses of azo dyes to the aquatic environment, one of the questions which need to be addressed is the fate of the aromatic amine cleavage products which may be expected when such dyes are attacked by anaerobic bacteria. The influence of test conditions has therefore been tested on the aerobic biodegradability of one such aromatic amine p-anisidine. Biodegradability of 20 mg/L DOC p-anisidine was carried out under the conditions essentially as described under the OECD Guideline methods 301A (modified AFNOR) and 301E (modified OECD Screenin 9 Test. Aniline was used as a reference substance. The days for analysis were 0, 3, 7, 14, 21 and 28 and analysis was done by both DOC and by specific analysis (gas chromatography recommended). Laboratories B, C and D show p-anisidine to have good degradation under 301A conditions and no degradation under 301E conditions. Laboratories A, E and F show p-anisidine to be readily degradable under 301A under 301E conditions. p-anisidine is readily biodegradable. Thus, if azo dyes are anaerobically cleaved to these particular amines it seems unlikely that they will remain unchanged in the environment for any substantial period of time. Similarly, if these amines are discharged in the effluents arising from dye manufacture it seems probable that they will be degraded during the biological treatment of such effluents.

 

Biodegradability test was performed (H.J.Kool, 1984) for p-anisidine. As a consequence of the activities of modern industry and agriculture, many man-made organic compounds have found their way into the environment, without much knowledge being available on their possible harmful effects on the environment. Chemical survey of micropollutants in the rivers Rhine and Meuse have suggested that in particular the river Rhine is polluted with considerable quantities of organic compounds including mutagens and carcinogens. To protect the environment and mankind against the potential risks which may arise from the discharging of (new) chemical substances, the European Community has laid down appropriate measures in a Council Directive. The influence of different types of inocula as well as the amount of inoculum (microbial biomass) on the biodegradation pattern of acetate,   4- methoxyaniline isomers was investigated in the NPR guideline. Activated sludge of a good quality collected from a treatment plant with predominantly domestic sewage was used. Microbial biomass was measured by means of ATP as a parameter for biodegradation estimation Using activated sludge (1.5 ml/L) as inoculum 4-methoxy aniline could be degraded for 60% completely by the NPR guideline.

Since these results were reproducible it implies that in the inoculum a minimal microbial biomass have to be present, which is able to survive the concentration (toxicity) of the compound and the test environment, and has the ability to metabolize the specific organic compound. Consequently, the higher the inoculum, the greater the chance to find these bacteria in the inoculum in sufficient amounts which will lead to more reproducible results.

 

Estimation Programs Interface Suite (EPI suite) was run to predict the biodegradation potential of the test compound Benzenamine, 4-methoxy- (p-Anisidine) (CAS no 104-94-9). The screening test inherent to the biodegradability of the substance was calculated using the software BIOWIN v4.10. The results indicate that Benzenamine, 4-methoxy- (p-Anisidine) is not expected to be readily biodegradable.

 

 

Biodegradation in water and sediment: simulation tests

Half life period of Benzenamine, 4-methoxy- (p-Anisidine)in water is observed to be 37.5 days (900 hrs.) while in sediment it is 337.5 days (8100 hrs). Based on these half life values of Benzenamine, 4-methoxy- (p-Anisidine), it is concluded that the chemical is not persistent in water and sediment.

 

Biodegradation in soil

EPI Suite has estimated that Benzenamine, 4-methoxy- (p-Anisidine) is expected to be found not predominantly in soil and its not persistence estimate is based on its transformation in this medium. Its half-life in soil, 75 days (1800 hrs), does not exceeds the threshold of 120 days as per Annex XIII of REACH.

 

Bioaccumulation: aquatic / sediment

The estimated bioconcentration factor (BCF) for Benzenamine, 4-methoxy- (p-Anisidine) is 3.162 L/kg, that does not exceed the bioconcentration threshold of 2000. Thus it is concluded that Benzenamine, 4-methoxy- (p-Anisidine)is not expected to bioaccumulate in the food chain because it does not exceed the BCF criteria.

 

Adsorption / desorption

The soil adsorption coefficient (Koc) value of Benzenamine, 4-methoxy- (p-Anisidine) is estimated to be 45 L/kg, indicating that it is has a low sorption to soil and sediment and therefore have good migration potential to groundwater