o-anisic acid

Endpoint summary

Description of key information

Biodegradation in water

Biodegradation study was conducted for 5 days for evaluating the percentage biodegradability of test substance 2-methoxybenzoic acid(CAS no. 579-75-9)

(GUANG H. LU et. al, 2003).The study was performed using the standard iodometric titration method.River water was used as a test inoculum obtained fromJilin section in the Songhua river. Temperature of the water sample was 15-20°C, pH 6.8 – 7.0 and dissolved oxygen was ranged between 7.8 – 9.0 mg/l, respectively. The bacterial counts were determined by standard plate count techniques and are about 1,200 to 3000 colony forming units/ml. Initial test substance conc. used in the study was 2 mg/l on the basis of ThOD. Residual DO of the test chemical was at least 1 mg/l at the final day. The test chemical was added to 250 ml BOD bottles. The composition ofthe medium contained 3 g of beef extract, 10 g of peptone, 20 g of agar, and 1 L of distilled water. After the adjustment of pH of the medium (pH 7.4-7.6), the culture was sterilized for 20 min at 1218C. One milliliter of diluted water sample was cultivated in 15 ml of the above medium at 31°C for 24 h, and the number of colonies was enumerated as the bacterial counts.The bottles were then filled to capacity with the water sample, sealed and incubated for 5 days at 20 ± 1°C.Two replicates were conducted for each chemical and each control (inoculum only).The DO concentrations were determined by the iodometric titration method.Biodegradability was assessed by measuring the BOD values in milligrams per liter (oxygen uptake values of test compound minus control).Biodegradability was expressed as the first-order kinetic rate constant (K) according to the traditional Monod equation (on the assumption that the bacterial counts were invariable during the experimental period).The total surface area of molecules, the heat of formation (Hf), and the energy of the highest occupied molecular orbital (EHOMO) of test chemical was calculated by the quantum chemical method Mopac Program. The linear regression analyses were performed with the SPSS®statistical package (Ver 10.0, SPSS, Chicago, IL, USA).An obvious negative correlation apparently exists betweenHf andK,that is, the lower theHf value (-422.08 kj/M), the higher theKvalue (1.06/d), and thus based on this relationship, test chemical was considered to be readily biodegradable by river bacteria.

Biodegradation in water and sediment

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound 2-methoxy benzoic acid (CAS No. 579 -75 -9). If released in to the environment, 32.2% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 2-methoxybenzoic acid in water is estimated to be 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is moderate to low whereas the half-life period of 2-methoxybenzoic acid

in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.0736%), indicates that 2 -methoxybenzoic acid is not persistent in sediment.

 

Biodegradation in soil

The half-life period of 2-methoxybenzoic acid (CAS No. 579 -75 -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, 67.1% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 2-methoxybenzoic acid in soil is estimated to be 30 days (720 hrs). Based on this half-life value of 2-methoxybenzoic acid

, 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

Biodegradation in water

Various experimental study and supporting data for the target compound 2-methoxybenzoic acid(CAS No. 579-75-9) alongwith the supporting study for its closest read across substance with were reviewed for the biodegradation end point which are summarized as below:

 

In an experimental key study from peer reviewed journal (GUANG H. LU et. al, 2003), biodegradation study was conducted for 5 days for evaluating the percentage biodegradability of test substance 2-methoxybenzoic acid (CAS no. 579-75-9).The study was performed using the standard iodometric titration method. River water was used as a test inoculum obtained from Jilin section in the Songhua river. Temperature of the water sample was 15-20°C, pH 6.8 – 7.0 and dissolved oxygen was ranged between 7.8 – 9.0 mg/l, respectively. The bacterial counts were determined by standard plate count techniques and are about 1,200 to 3000 colony forming units/ml. Initial test substance conc. used in the study was 2 mg/l on the basis of ThOD. Residual DO of the test chemical was at least 1 mg/l at the final day. The test chemical was added to 250 ml BOD bottles. The composition of the medium contained 3 g of beef extract, 10 g of peptone, 20 g of agar, and 1 L of distilled water. After the adjustment of pH of the medium (pH 7.4-7.6), the culture was sterilized for 20 min at 1218C. One milliliter of diluted water sample was cultivated in 15 ml of the above medium at 31°C for 24 h, and the number of colonies was enumerated as the bacterial counts. The bottles were then filled to capacity with the water sample, sealed and incubated for 5 days at 20 ± 1°C.Two replicates were conducted for each chemical and each control (inoculum only).The DO concentrations were determined by the iodometric titration method. Biodegradability was assessed by measuring the BOD values in milligrams per liter (oxygen uptake values of test compound minus control).Biodegradability was expressed as the first-order kinetic rate constant (K) according to the traditional Monod equation (on the assumption that the bacterial counts were invariable during the experimental period).The total surface area of molecules, the heat of formation (Hf), and the energy of the highest occupied molecular orbital (EHOMO) of test chemical was calculated by the quantum chemical method Mopac Program. The linear regression analyses were performed with the SPSS® statistical package (Ver 10.0, SPSS, Chicago, IL, USA).An obvious negative correlation apparently exists between Hf and K,that is, the lower the Hf value (-422.08 kj/M), the higher the K value (1.06/d), and thus based on this relationship, test chemical was considered to be readily biodegradable by river bacteria.

 

In a supporting data, biodegradation experiment was conducted for 5 days for evaluating the percentage biodegradability of test substance 2-methoxybenzoic acid (CAS no. 579-75-9) (G. H. Lu et. al, 2002).The study was performed using the standard iodometric titration method. River water was used as a test inoculum obtained from Jilin section in the Songhua river. Temperature of the water sample was 15-20°C, pH 6.8 – 7.0 and dissolved oxygen was about 8.0 mg/l, respectively. The bacterial counts were determined by standard plate count techniques and are about 800-3000/ml. Initial test substance conc. used in the study was 2 mg/l on the basis of ThOD. Residual DO of the test chemical was at least 1 mg/l at the final day. The test chemical was added to 150 ml of water sample in 250 ml BOD bottles. The bottles were then filled to capacity with the water sample, sealed and incubated for 5 days at 20 ± 1°C. The DO concentrations were determined by the iodometric titration method. The test result was expressed as BOD% by comparing the measured BOD5 with ThOD. Mw, Hf and Ehomo of test chemical was calculated by the quantum chemical method MOPAC 6.0-AMI on energy minimized structures. The percentage degradation of test substance was determined to be 55.8% by using BOD parameter in 5 days. Thus, based on percentage degradation, 2-methoxybenzoic acid is considered to be biodegradable in nature.

 

Another biodegradation study was conducted for 14 days for evaluating the percentage biodegradability of test substance 2-ethyl-9,10-anthraquinone (CAS no. 84-51-5) (GERHARD ZELLNER et. al, 1990). Micro-organisms (Desulfovibrio vulgaris Marburg, Desulfovibrio simplex" XVI and Desulfovibriosp. Strain MP47) was used as a test inoculum. Desulfovibrio vulgaris Marburg DSM 2119 was obtained from Hans Hippe, Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Braunschweig, Federal Republic of Germany. "Desulfovibrio simplex" XVI DSM 4141 and Desulfovibrio sp. strain MP47 were isolated from a laboratory digester for the biomethanation of whey. Desulfovibrio vulgaris Marburg, "Desulfovibrio simplex" XVI, and Desulfovibrio sp. Strain MP47 were routinely cultured in a medium that contained the following (per liter): 4.25 g of Na2SO4, 0.255 g of K2HPO4, 0.255 g of KH2PO4, 0.255 g of (NH4)2S04, 0.45 g of NaCl, 0.10 g of MgSO4 - 7H20, 2.0 g of yeast extract, 60 mg of CaCl2, 4 mg of FeSO4, 24 mg of Ni(NH4)2(SO4)2, and 1 mg of resazurin. The medium was supplemented with 10 ml each of vitamin and mineral solutions and reduced by the addition of 0.5 g of L-cysteine hydrochloride and 0.5 g of Na2S.9H20 per liter.Initial test substance conc. used in the study was 250 mg/20 ml.Parallel cultures in serum bottles containing 20 ml of medium and 250 mg of any one of the substrates mentioned above per liter were incubated under N2-CO2 (80:20%, 300 kPa) at 37°C on a shaker (100 rpm) for 4 weeks. Biotransformation of the substrates was analyzed by at least two methods, including HPLC with two detector systems, UV spectroscopy at 254 nm (293 nm for pyridoxal hydrochloride), and thin-layer chromatography.

Optical density of cultures was measured with a photometer (Stasar II; Gilford Instrument Laboratories, Inc., Oberlin, Ohio) at a wavelength of 578 nm. Samples were withdrawn from the serum bottles with a syringe, transferred into a quartz cuvette, and reduced with a grain of sodium dithionite. All growth measurements were carried out with the same cuvette and controlled by microscopic counting. Optical density measurements of parallel cultures were corrected for the absorbance measured immediately after inoculation and for the absorbance reached in control cultures in the absence of an added electron donor for sulfate reduction. As no growth of test organism was obtained using the test chemical as a substrate, no transformation of 2-methoxybenzoic acid was determined in 28 days. Thus, 2 -methoxybenzoic acid is considered to be not readily biodegradable in nature.

 

In a supporting study fromauthoritative database(J-CHECK, 2016) for read across substance o-acetylsalicylic acid (CAS no. 50-78-2),biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of read across substance o-acetylsalicylic acid. Concentration of inoculum i.e, sludge used was 30 mg/l and initial substance conc. used in the study was 100 mg/l, respectively. At the beginning of the test, the pH of the test solution was adjusted. The percentage degradation of read across substance was determined to be 86, 97 and 100% degradation by BOD, TOC removal and HPLC parameter in 28 days. The read across substance was hydrolyzed to form Salicylic acid and Acetic acid in (Water + Test Substance) systems. Thus, based on percentage degradation, o-acetylsalicylic acid is considered to be readily biodegradable in nature.

 

Although one study(GERHARD ZELLNER et. al, 1990)indicate that the chemical2-methoxybenzoic acid is not readily biodegradable, on thebasis of overall reported results for target chemical2-methoxybenzoic acid(from peer reviewed journal) and for its read across substance (from authoritative database J-CHECK), it can be concluded that the test substance2-methoxybenzoic acidcan be expected to be readily biodegradable in nature.

Biodegradation in water and sediment

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound 2-methoxy benzoic acid (CAS No. 579 -75 -9). If released in to the environment, 32.2% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 2-methoxybenzoic acid in water is estimated to be 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is moderate to low whereas the half-life period of 2-methoxybenzoic acid

in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.0736%), indicates that 2 -methoxybenzoic acid is not persistent in sediment.

Biodegradation in soil

The half-life period of 2-methoxybenzoic acid (CAS No. 579 -75 -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, 67.1% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 2-methoxybenzoic acid in soil is estimated to be 30 days (720 hrs). Based on this half-life value of 2-methoxybenzoic acid

, 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.

On the basis of available information, the test substance 2-methoxybenzoic acid can be considered to be readily biodegradable in nature.