4-methoxyphenylacetic acid

Endpoint summary

Description of key information

Short-term toxicity to fish

Fish Acute Toxicity test according to OECD Guideline 203 was conducted for 4-methoxyphenylacetic acid. The nominal concentration selected for the experiment were 100mg/L and test fish were exposed to these concentration for 96 hours. The median lethal concentration (LC50) for 4-methoxyphenylacetic acid on Danio rerio in a 96 hours study on the basis of mortality effect was found to be >100 mg/L. Thus, on the basis of this LC50 value and according to CLP criteria for aquatic classification of the substance, it is concluded that the substance, 4-methoxyphenylacetic acid (CAS No. 104-01-8) does not exhibit short term toxicity to fish.

LC0 (96 hours) (highest loading at which no mortality was observed) = 100 mg/L

LC50 (96 hours) Experimental = >100 mg/L

Short-term toxicity to aquatic invertebrates

Determination of the inhibition of the mobility of Daphnids was carried out with the substance4-methoxyphenylacetic acidaccording to OECD Guideline 202.

The stock solution 150.0 mg/L was prepared by dissolving white powder in reconstituted water. The solution was kept in ultrasonic bath for 20 min. The test solutions of required concentrations were prpared by mixing the stock solution of the test sample in reconstituted water.The test substance was tested at the concentrations 0, 30.0, 45.0, 67.5, 100.0 and 150.0 mg/L.The test was performed under static conditions in a fresh water system at a temperature of 20 °C± 1 °C. EC50 was calculated using non linear regression by the software Prism 4.0.

The median effective concentration (EC50) for the test substance,4-methoxyphenylacetic acid, in Daphnia magna was determined to be 100.8 mg/L for immobilisation effects with 95% CI of 94.7 to 107.4 mg/L. Thus, based on this EC50 value and after comparing with CLP criteria for aquatic classification of the substance it is concluded that the substance,4-methoxyphenylacetic aciddoes not exhibit short term toxicity to aquatic invertebrate (Daphnia Magna).

Toxicity to aquatic algae and cyanobacteria

The freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance4-methoxyphenylacetic acid(CAS No.- 104 -01 -8) according to OECD Guideline 201.

The stock solution 150.0 mg/L was prepared by dissolving white powder in OECD growth medium. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture and tested at the concentrations 0, 0, 30.0, 45.0, 67.5, 100.0 and 150.0 mg/L.Effects on the growth rate of the organism were studied. The test was performed under static conditions in a static fresh water system at a temperature of 23± 2°C. Initial cell density of test organism used was 5x10(3) cells/ml. Determination of cell counting involve the use of microscope with counting chamber Cyrus I or electronic particle counter. ErC50 was calculated using non-linear regression by the software Prism 4.0.

The median effective concentration (ErC50) for the test substance,4-methoxyphenylacetic acid, in a freshwater algae Desmodesmus subspicatus was determined to be 106.9 mg/L on the basis of effects on growth rate in a 72 hour study with 95% Cl of 83.2 - 137.3 mg/L. Thus, based on this ErC50 value and according to CLP Criteria for aquatic classification of the substance, it is concluded that4-methoxyphenylacetic acid(CAS No.- 104 -01 -8) does not exhibits toxicity to aquatic algae (Desmodesmus subspicatus).

Toxicity to microorganisms

A study was predicted using OECD QSAR toolbox version 3.3, to assess the toxicity effect of4-methoxyphenylacetic acid(CAS No. 104 -01 -8) in microorganism (tetra hymena pyr iformis) in a 48 hours of exposure. The inhibition growth concentration (IGC50) of4-methoxyphenylacetic acidin microorganism (Tetrahymena pyrifor mis) on the basis of growth inhibition effect was estimated to be 678.87 mg/L. Thus, it can be concluded that the test substance4-methoxyphenylacetic acid(CAS No. 104 -01 -8) does not exhibit any toxicity effect to microorganism.

Additional information

Short-term toxicity to fish

Various studies including experimental data following OECD guideline and predicted results from validated model for toxicity to fish with the target substance 4-methoxyphenylacetic acid (CAS no. 104-01-8) and to its relevant read across substance (4-chloro-2-methylphenoxy)acetic acid (CAS No. 94-74-6) by considering its structure-activity relationships, were summarized as follows:

 

Fish Acute Toxicity test according to OECD Guideline 203 was conducted by UERL (2017) for 4-methoxyphenylacetic acid. The nominal concentration selected for the experiment were 100 mg/L and test fish were exposed to these concentration for 96 hours. The median lethal concentration (LC50) for 4-methoxyphenylacetic acid on Danio rerio in a 96 hours study on the basis of mortality effect was found to be >100 mg/L.

LC0 (96 hours) (highest loading at which no mortality was observed) = 100 mg/L

LC50 (96 hours) Experimental = >100 mg/L

 

Also, based on the Ecological Structure Activity Relationships (ECOSAR) Predictive Model version 1.11 (2017), the median lethal concentration (LC50) for the test substance, 4-methoxyphenylacetic acid, in fish was estimated to be 3765.923 mg/L on the basis of mortality effect in a 96 hour study.

 

Moreover, in another study for the read across substance (4-chloro-2-methylphenoxy)acetic acid (CAS No. 94-74-6) published in an authoritative database such as ECOTOX database (2017), the study was designed to assess the toxic effects of the test compound (4-chloro-2-methylphenoxy)acetic acid on the Salmo trutta in a 96 hrs. of exposure.In the experiment static condition maintained with 11 mg/L CaCO3 hardness, 10 Deg.C test temperature, 6.3 pH and 3.2 mS/m conductivity. On the basis of mortality effect the lethal concentration (LC50) on fish Salmo trutta (Brown Trout) was observed to be 300 mg/l. 

 

So, based on the above predicted and experimental studies for target substance 4-methoxyphenylacetic acid (CAS no. 104-01-8) and the read across substance, the lethal concentration LC50 was found to be in the range of >100 mg/L to 3765.923 mg/L. Thus, on the basis of this LC50 value and according to CLP criteria for aquatic classification of the substance, it is concluded that the substance, 4-methoxyphenylac etic acid (CAS No. 104-01-8) does not exhibit short term toxicity to fish.

Short-term toxicity to aquatic invertebrates

Various studies including experimental data following OECD guideline and predicted results from validated model for toxicity to aquatic invertebrates with the target substance 4-methoxyphenylacetic acid (CAS No. 104-01-8) and the relevant read across substances 4-Hydroxy-3-methoxybenzoic (vanillic) acid (121 -34 -6) and 4-Methoxybenzoic acid (100-09-4) by considering its structure-activity relationships,were summarized as follows:

 

Determination of the inhibition of the mobility of Daphnids was carried out with the substance 4-methoxyphenylacetic acid according to OECD Guideline 202.

The stock solution 150.0 mg/L was prepared by dissolving white powder in reconstituted water. The solution was kept in ultrasonic bath for 20 min. The test solutions of required concentrations were prpared by mixing the stock solution of the test sample in reconstituted water. The test substance was tested at the concentrations  0, 30.0, 45.0, 67.5, 100.0 and 150.0 mg/L. The test was performed under static conditions in a fresh water system at a temperature of 20 °C± 1 °C. EC50 was calculated using non linear regression by the software Prism 4.0.

The median effective concentration (EC50) for the test substance, 4-methoxyphenylacetic acid, in Daphnia magna was determined to be 100.8 mg/L for immobilisa tion effects with 95% CI of 94.7 to 107.4 mg/L.

 

Also, based on the Ecological Structure Activity Relationships (ECOSAR) Predictive Model version 1.11 (2017), the median lethal concentration (LC50) for the test substance, 4-methoxyphenylacetic acid, in daphnia magna was estimated to be 2043.6 mg/L on the basis of mortality effect in a 48 hour study.

 

In another study for the read across substance conducted by Yasushi Kamaya et al.(Chemosphere 59 (2005) 255–261). The short term toxicity to aquatic invertebrates was performed in Daphnia magna for 48 hrs. The young daphnids were obtained from continuous cultures in 1 liter glass beakers at 21 ± 0.3 degree C, in dechlorinated and conditioned tap water, the medium was renewed in three weeks and daphnids were fed daily with the green alga Selenastrum capricornutum. The pH of test solution was adjusted to 7.45 ± 0.05 with HCL and NaOH. The concentrations of the resultant solutions were checked before and after (48 h) exposure using a UV–visible spectrophotometer. At the start of the experiment neonate were placed in 50 ml of beaker with 40 ml of test solution. All experiment was made in four replicates and performed at 21 ± 0.3 degree C under 16 h light: 8 h dark photoperiod. Immobility was observed after 24 and 48 hrs and EC 50 value was calculated. The EC 50 value of 4-Hydroxy-3-methoxybenzoic (vanillic) acid (121 -34 -6) for Daphnia magna was determined to be 908 mg/l in 48 hrs.

 

Moreover, short-term toxicity to aquatic invertebrates was conducted by Yasushi Kamaya et al.( Chemosphere 59 (2005) 255–261), in Daphnia magna for 48 hrs. The young daphnids were obtained from continuous cultures in 1 liter glass beakers at 21 ± 0.3 degree C, in dechlorinated and conditioned tap water, the medium was renewed in three weeks and daphnids were fed daily with the green alga Selenastrum capricornutum. The pH of test solution was adjusted to 7.45 ± 0.05 with HCL and NaOH. The concentrations of the resultant solutions were checked before and after (48 h) exposure using a UV–visible spectrophotometer. At the start of the experimentneonate were placed in 50 ml of beaker with 40 ml of test solution. All experiment was made in four replicates and performed at 21 ± 0.3 degree C under 16 h light: 8 h dark photoperiod. Immobility was observed after 24 and 48 hrs and EC 50 value was calculated. After the experiment the EC 50 value of 4-Methoxybenzoic acid (100-09-4) for Daphnia magna was determined to be 943 mg/l in 48 hrs of exposure.

 

So, based on the above experimental studies for target substance 4-methoxyphenylacetic acid (CAS No. 104-01-8) and the relevant read across substances 4-Hydroxy-3-methoxybenzoic (vanillic) acid (121 -34 -6) and 4-Methoxybenzoic acid (100-09-4), the median effective concentration (EC50) was found to be in the range of 100.8 – 943 mg/L and the lethal concentration (LC50) to be 2043.6 mg/L on the basis of various effects (mobility and mortality) in a 48 hours of exposure. Thus, based on this EC50 value and after comparing with CLP criteria for aquatic classification of the substance it is concluded that the substance, 4-methoxyphenylacetic acid does not exhibit short term toxicity to aquatic invertebrate (Daphnia Magna).

Toxicity to aquatic algae and cyanobacteria

Various experimental studies following OECD guideline for toxicity to aquatic algae with the target substance 4-methoxyphenylacetic acid (CAS No. 104-01-8) and the relevant read across substance 2-(2,4-dichlorophenoxy)propanoic acid (CAS No. 120-36-5) by considering its structure-activity relationships, were summarized as follows:

 

The freshwater algal growth inhibition test was carried out by SSS (2017) on Desmodesmus subspicatus with the substance 4-methoxyphenylacetic acid (CAS No.- 104 -01 -8) according to OECD Guideline 201. The stock solution 150.0 mg/L was prepared by dissolving white powder in OECD growth medium. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture and tested at the concentrations 0, 0, 30.0, 45.0, 67.5, 100.0 and 150.0 mg/L. Effects on the growth rate of the organism were studied. The test was performed under static conditions in a static fresh water system at a temperature of 23± 2°C. Initial cell density of test organism used was 5x10(3) cells/ml. Determination of cell counting involve the use of microscope with counting chamber Cyrus I or electronic particle counter. ErC50 was calculated using non-linear regression by the software Prism 4.0.

The median effective concentration (ErC50) for the test substance, 4-methoxyphenylacetic acid , in a freshwater algae Desmodesmus subspicatus was determined to be 106.9 mg/L on the basis of effects on growth rate in a 72 hour study with 95% Cl of 83.2 - 137.3 mg/L.

 

The above study is supported by another experimental study conducted by UERL (2017). The effect of test item 4-methoxyphenylacetic acid, CAS No. 104-01-8 was studied on the growth of fresh water green alga Chlorella vulgaris. The study was conducted following OECD guideline 201- Alga, growth inhibition test. The test concentration chosen for the study were 0.9 mg/L,2.7 mg/L,8.1 mg/L,24.3 mg/L,72.9 mg/L,218.7 mg/L. The test concentrations were prepared using stock solution of the test item using mineral media. The green alga was exposed to the test concentration for a period of 72 hours to observe average specific growth rate and % growth inhibition under the effect of the test item. EC50 calculated graphically through probit analysis was observed to be >200 mg/L.

 

Moreover, the short term toxicity to Selenastrum capricornutum strain NIVA-CHL 1(green algae) study for read across substance 2-(2,4-dichlorophenoxy)prop anoic acid (CAS No. 120-36-5) was carried out by Mohammad I. Abdel-Hamid (Water Science and Technology, Vol. 33, No. 6, Pg. no. 129-138, 1996) using the microplate test for 96 hrs. The study was based on the effects of the test compound 2-(2,4-dichlorophenoxy)propanoic acid on Selenastrum capricornutum(green algae) in a static fresh water system. The chlorococcal alga Selenastrum capricomutum strain NIV A-CHL. 1 (nowRaphidocelis subcapitala) was obtained from the culture collection of the Norwegian Institute for Water Research, Oslo, Norway.The alga was cultivated in standard AAM medium. The culture flasks were placed on a shaking table at 22±2 'C under continuous illumination (approx.70µE m-2s-I) provided by white fluorescent tubes. Test chemical conc. used for the study were 320, 100, 32, 10, 3.2, 1.0, 0.32, 0.1, 0.032, 0.01,&0.0032 mg/I, respectively. To each well on the polystyrene microplates, 1.8 ml of algal inoculum was added. Stock solutions containing 3.2 g I-I (stock A) and 1.0 g I-I (stock B) were prepared for each pesticide. To the first and to the second wells on the plate, a volume of 0.2 ml was added from stock A and stock B, respectively. The contents of each well were, then, thoroughly mixed and 0.2ml was transferred from the well I to 3 and from 2 to 4. The serial dilutions were repeated down the row of wells on two successive plates to give 11 concentrations (320, 100, 32, 10, 3.2, 1.0, 0.32, 0.1, 0.032, 0.01,&0.0032 mg I-I) and one left as control.The test plates were incubated at 22±2 'C under continuous illumination (approx.70µE m-2s-I)provided by white fluorescent tubes. The test was terminated after an incubation period of four days.Cell density of the free cultures 10 each well was counted using a Coulter Multisizer(Software Level 1.8).At the same time the corresponding mean cell volume (MCV,µm3cell-1) was also determined. Algal dry weight was calculated from cell density and MCV. EC50 is the effective median concentration that inhibits algal growth by 50%, compared with control culture. Values of the toxicity-response parameter (algal dry weight) were plotted, as relative percent’s of the Control (control=100%), against the logarithm of the corresponding pesticide concentration. A curve was fitted to the points by third level pesticide polynomial. This allowed the calculation of EC50 by the straight line graphical interpolation method. The lowest concentrations giving no observable algal growths (EC 100) were visually detected. On the basis of effect on growth rate of the test organism Selenastrum capricornutum(green algae),the 96 hr EC50 and EC100 value was determined to be 190 and >320 mg/l, respectively.

 

So, based on the above experimental studies for target substance 4-methoxyphenylacetic acid (CAS No. 104-01-8) and to its relevant read across substa nce, the effective concentration (EC50) value was found to be in the range of 106.9 mg/L to >200 mg/L and EC100 value to be >320 mg/L.

Therefore, according to the CLP Criteria for aquatic classification of the substance, it is concluded that 4-methoxyphenylacetic acid (CAS No. 104-01-8) does not exhibit toxicity to aquatic algae.

Toxicity to microorganisms

Various studies including predicted results from validated model and experimental study from a peer-reviewed journal for toxicity to microorganism with the target substance 4-methoxyphenylacetic acid (CAS No. 104-01-8) and the relevant read across substance (4-chloro-2-methylphenoxy)acetic acid (No. 94 -74 -6) by considering its structure-activity relationships, were summarized as follows:

 

A study was predicted using OECD QSAR toolbox version 3.3, to assess the toxicity effect of 4-methoxyphenylacetic acid(CAS No. 104 -01 -8) in microorganism (tetrahymena pyriformis) in a 48 hours of exposure. The inhibition growth concentration (IGC50) of 4-methoxyphenylacetic acid in microorganism (Tetrahymena pyrifor mis) on the basis of growth inhibition effect was estimated to be 678.87 mg/L.

 

Moreover, a toxicity test using protozoa as test organism was devised by Schreiber,B. et al. ( Biol Fertil Softs (1989) 7:289-296) for read across substance (4-chloro-2-methylphenoxy) acetic acid (CAS No.- 94 -74 -6). Two different methods were used, the most probable number method and the absorbance method (based on measurement of protozoa growth through absorbance). The ciliate Colpoda cucullus was isolated from different biological starter cultures and tested with the herbicides MCPA. The 9-h LC50 (concentration at which 50% of the protozeon population has died after 9 h of incubation) was found to be 100 mg/L.

 

Thus, based on the above predicted and experimental studies for target substance 4-methoxyphenyl acetic acid (CAS No. 104-01-8) and to its read across substance (4-chloro-2-methylphenoxy)acetic acid (No. 94 -74 -6), the inhibition growth concentration (IGC50) was found to be 678.87 mg/L and LC50 to be 100.0 mg/L on the basis of various effects (growth inhibition and population effect) in a 9 to 48 hours of exposure.