N-(2-phenoxyphenyl)methanesulphonamide

Endpoint summary

Description of key information

Short term toxicity to fish

Based on the prediction done using the EPI Suite ECOSAR version 1.10, the 96hr toxicity on fish was predicted for test substance N-(2 -phenoxyphenyl)methanesulfonamide (CAS: 51765 -51 -6). On the basis of effects observed in a static freshwater system, the lethal concentration LC50 value for the substance is estimated to be 93.634 mg/l . Based on this value, the test chemical can be considered to be classified in aquatic chronic category 3 as per the CLP classification criteria.

Short term toxicity to aquatic invertebrates

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, the short term toxicity on aquatic invertebrates was predicted forN-(2-phenoxyphenyl)methanesulphonamide(CAS: 51765-51-6). EC50 value was estimated to be 21.34 mg/l for Daphnia magna for 48 hrs duration.

Toxicity to aquatic algae and cyanobacteria

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, the short term toxicity on aquatic algae and cyanobacteria was predicted for target substance N-(2-phenoxyphenyl)methanesulfonamide

 (CAS no. 51765-51-6) (2017). EC50 value was estimated to be 21.83 mg/l for Pseudokirchneriella subcapitata for 72 h duration. Based on this value it can be concluded that the substance N-(2 -phenoxyphenyl)methanesulfonamide is considered to be toxic to aquatic environment and can be considered to be classified in aquatic chronic category 3 as per the CLP classification criteria.

Additional information

Short term toxicity to fish

Based on the prediction done using the EPI Suite ECOSAR version 1.10, the 96hr toxicity on fish was predicted for test substance N-(2 -phenoxyphenyl)methanesulfonamide (CAS: 51765 -51 -6). On the basis of effects observed in a static freshwater system, the lethal concentration LC50 value for the substance is estimated to be 93.634 mg/l . Based on this value, the test chemical can be considered to be classified in aquatic chronic category 3 as per the CLP classification criteria.

Short term toxicity to aquatic invertebrates

Short term toxicity to aquatic invertebrates for N-(2-phenoxyphenyl) methanesulphonamide(CAS: 51765-51-6) was summarised with two predicted data for target and two experimental studies of two read across substances:

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, the short term toxicity on aquatic invertebrates was predicted forN-(2-phenoxyphenyl)methanesulphonamide(CAS: 51765-51-6). EC50 value was estimated to be 21.34 mg/l for Daphnia magna for 48 hrs duration.

Another prediction based on the QSAR using the EPI Suite ECOSAR version 1.10, the 48 hours EC50 was estimated to be 55.191 mg/l on Daphnia Magna for substance N-(2-phenoxyphenyl) methanesulphonamide with immobilization effects. Thus based on this value it can be concluded that the substance can be classified as aquatic chronic 3 as per the criteria of CLP regulation.

Study was performed in read across Ametryn (834-12-8) by Z. Clementeet al. (Journal of Nanoscience and Nanotechnology Vol. 13, 1–7, 2013) for 48 hrs on the concentration range from 30.71–49.66 mg/l. The test solutions were prepared using dechlorinated water (pH 7.5, conductivity 106µS/cm, and hardness 50 ppm of CaCO3) that had been previously aerated for at least 24 h. Test was conducted at 20±2ᵒC, under constant illumination, and daphnia were not fed during the test. Mobility was counted after 24 and 48 h of exposure. The results were analyzed using the StatGraphics Centurion IV program. On the basis of observation the EC 50 value for 48 hrs of Ametryn (834-12-8) for short term toxicity to aquatic invertebrates was determined to be 38.86 mg/l. 

Study on another read across desmetryn (1014-69-3) from ecotox database, 2017 was performed in Daphnia magna for 24 hrs at concentration range from 90.5-125 mg/l. The test was performed in static fresh water system using < 24 hrs daphnia magna. After 24 hrs, the EC 50 value for desmetryn (1014-69-3) was determined to be 26 mg/l. Based on the value, the chemical was considered to be toxic to aquatic invertebrates and can be considered to be classified in chronic category 3 as per the CLP regulations.

Based on the above predicted data and studies of read across chemicals it can be considered that all the above studies supported the target classification. Based on the results it was considered that all weight of evidences supported the classifications andN-(2-phenoxyphenyl)methanesulfonamide(CAS: 51765-51-6)was hazardous to aquatic invertebrates andcan be considered to be classified in chronic category 3 as per the CLP regulations.

Toxicity to aquatic algae and cyanobacteria

Predicted data for the target chemical N-(2-phenoxyphenyl)methanesulfonamide (CAS No. 51765-51-6) and weight of evidence study for its read across substancewere reviewed to summarize the following information:

 

Short term toxicity on aquatic algae and cyanobacteria of target chemical N-(2-phenoxyphenyl)methanesulfonamide (CAS No. 51765-51-6) is predicted using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances (2017).EC50 value was estimated to be 21.83 mg/l for Pseudokirchneriella subcapitata for 72 h duration.

 

In another prediction done using the EPI Suite ECOSAR version 1.10, the short term toxicity on green algae was predicted for test substance N-(2-phenoxyphenyl)methanesulfonamide(CAS No. 51765-51-6).On the basis of effects observed in a static freshwater system, the effect concentration EC50 value for the substance is estimated to be 47.984 mg/l for green algae for 96 h duration.

 

In a weight of evidence study of the read across chemical 2-methylbut-2-ene (CAS no. 513-35-9), short term toxicity to Pseudokirchneriella subcapitata (formerly Selenastrum capricornutum) study was carried out for 96 hrs (OECD SIDS, 2004 and High Production Volume Challenge Program, 2016). The study was performed according to OECD Guideline 201 (Alga, Growth Inhibition Test), EC Directive 92/69 C3, US EPA TSCA 797.1050 & 797.1060, respectively. The study was based on the effects of the read across compound 2-methylbut-2-ene on Selenastrum capricornutum(green algae)in a static fresh water system at a temperature of 22.3 – 23.4°C, pH range of7.2-7.4 with continuous light illumination, respectively. Pseudokirchneriella subcapitata was used as a test organism. Initial cell density of the test organism was1 × 10(4) cells/ml. Test chemical conc. used for the study was in the range of 22-29% (nominal conc.) and 19-27% of their nominal values at the start of the test (measured conc.), respectively. Based on an arithmetic mean, the overall mean measured levels of 2-methyl-2-butene were 0.689, 1.53, 3.61, 7.22 and 21.1 mg/l. Nominal test substance conc. used was 3.20, 7.04, 15.5, 34.1 and 75 mg/l, respectively. The test media were prepared, either directly or by dilution, from an aqueous preparation in which the test substance was stirred in a sealed vessel for approximately 23 hours in the dark. After being allowed to stand for at least one hour to obtain an equilibrium concentration of 2-methyl-2-butene, aliquots of medium were removed from the middle of the vessel and after dilution and inoculated with alga cells, was used to fill the test vessels. The area under the growth curve and the average specific growth rate are taken to be an index of growth and are calculated mathematically. The EbC50 ("x" h) is the median effect concentration for inhibition of growth based on a comparison of areas under the growth curves after "x" hours. The EbC50 was calculated using the moving average method of a computer program which uses percentage effect and the nominal and measured test concentration in test samples. The ErC50 ("x"-"y" h) is the median effect concentration for inhibition of growth based on a comparison of growth rates from "x" to "y" hours. The ErC50 was calculated by either the moving average method or by nonlinear interpolation between the two concentrations which bracket the 50% effect level of a computer program; the program uses percentage effect and the nominal and measured test concentration in test samples. The "no observed effect concentrations" (NOEC) was determined using Dunnett's multicomparison test to compare the percentage inhibition in the test group with that for the control cultures. After 72 and 96 hours of exposure to 2-methyl-2-butene, the EbC50 values were 10.5 and 10.1 mg/l respectively; the ErC50 values were 12.0 and 13.2 mg/l respectively. The "no observed effect concentration" (NOEC) for area under the growth curve and growth rate respectively, were 3.61 and 7.22 mg/l, respectively.

 

Thus, based on the overall reported results for target chemical N-(2-phenoxyphenyl)methanesulfonamide (OECD QSAR toolbox version 3.3 and EPI suite, 2017) and for its read across substance (fromsecondary source), it can be concluded that the test substance N-(2-phenoxyphenyl)methanesulfonamide can be considered as toxic to aquatic environment and can be considered to be classified in aquatic chronic category 3 as per the CLP classification criteria.