Methyl 2-naphthyl ether

Endpoint summary

Description of key information

Toxicity to soil macroorganisms except arthropods

The toxic effect of test chemical was studied on the earthworm, Eisenia fetida by artificial soil test. the study was conducted in two phases ie., range finding test and definitive test. The artificial soil was used as the substrate which was prepared as per the OECD 222 guidelines. As the test chemical was insoluble, acetone was used as carrier vehicle, simultaneously along with test concentrations both control (deionized water) and vehicle control (acetone) were also studied. Before initiation of the definitive study a range finding test was conducted at concentrations of 0.1, 1, 10, 100, 250, 500 and 1000 mg/kg dry. Based on number of cocoon and juvenile production, the concentrations for the main study was decided as 0.10, 0.18, 0.32, 0.58, 1.04, 1.88, 3.39, 6.11 and 11.00 mg/kg. Adult earthwormswith well-developed clitellum of age ranging from 4.5 to 5 months were exposed for definitive test concentrations with minimum number of 10 test organisms per replicate. The test was conducted for the period of 56 days with 8 replicates in control groups and 4 replicates in exposure groups. After mixing of test chemical with artificial soil at a wide range of test item concentrations in which the adult earthworms were placed for 28 days exposure. The mortality and growth effects of the test item on the adult earthworms were examined after 4 weeks of exposure. The adults are then removed from the soil and effects on reproduction was assessed after a further 4 weeks by counting the number of offspring present in the soil. The reproductive output of the worms exposed to the test item is compared to that of the control(s) to determine the no observed effect concentration (NOEC) / effective concentrations.

There was no mortality of earthworms in control, vehicle control and at the tested concentrations of0.10, 0.18, 0.32, 0.58, 1.04, 1.88, 3.39, 6.11 and 11.00mg/kg on Day 28. The percent mortality of earthworms at 3.0 mg a.i. of reference substance/kg dry soil was 17.5%. No pathological and behavioralsymptomswere observed in adult worms during the test period in the control, vehicle control and treated groups (including reference substance). No statistically significant reduction in body weight was observed in treated groups (except 0.32, 0.58, 1.04, 1.88, 3.39, 6.11 and 11.00 mg/kg dry soil and reference substance test group) as compared with the control or vehicle control.

No pathological and behavioral symptoms were observed in juveniles on Day 56 in the control, vehicle control and treated groups. No statistically significant reduction in juvenile production was observed in treated groups (except 0.32, 0.58, 1.04, 1.88, 3.39, 6.11 and 11.00 mg/kg dry soil and reference substance test group) as compared with the control or vehicle control. Cocoons were not present in any of tested groups and reference substance group. After obtaining all the required necessary outcomes, the generated data was treated for statistical analysis. the average body weights and juvenile production was evaluated using licensed copies of SYSTAT Statistical package version 12.0. Data was tested for normality (Shapiro-Wilk test) and homogeneity of variance (Levene’s) before performing further analysis. When data was found as normal and homogeneous, ANOVA was performed for overall group comparison and Dunnett’s test for pairwise comparison. When data was found as non-normal or non-homogeneous, then Kruskal-Wallis was performed for overall group comparison and Mann-Whitney U test for pairwise comparison. Comparison of means between reference substance group and control group was done using two-sample t-test and Mann-Whitney U test. All analyses and comparisons were evaluated at the 5% (p≤0.05) level.

To ensure the bio-availability of test chemical, the active ingredientof test concentrations of low, mid and high test concentrations ie., 0.10, 1.04 and 11.0 mg/kg dry soil were analysed using GC-MS-MS. All the validity criteria, ie., 1.Each replicate (containing 10 adults) produced minimum of 65 juveniles by the end of the test. 2. The coefficient of variation of reproduction is 4.3%. 3. There was no mortality of the earthworms in the control during the experimental period of 28 days, were met, andReference substance (Carbendazim) group exhibited statistically significant reduction in juvenile production at 3 mg a.i./kg dry soil as compared with the control making study valid.

Upon 28 days exposure there was no mortality in the adult earthworms, resulting LC50 >11mg/kg dry soil. After 56 days of exposure NOEC, LOEC, EC10 and EC50 was determined to be 0.18, 0.32, 0.1942 (0.07098-0.4143) and 1.811 (1.271-2.611). respectively.

 

Toxicity to terrestrial arthropods

In accordance with column 2 of Annex IX of the REACH regulation, the study does not need to be conducted because direct and indirect exposure of the soil compartment is unlikely considering its use as a flavouring agent and fragrance agent in perfumery, especially in soap perfumes.

 

Toxicity to terrestrial plants

The study aimed at evaluating the effect of test item on seedling emergence and seedling growth of 6 terrestrial plants was conducted on 2 monocotyledonous and 4 dicotyledonous species. The test item was mixed into the acid washed quartz sand (artificial substrate/soil which was used as the test medium) and exposed as per test guidelines.

A range finding test was carried out with the plant species (onion, corn, cabbage, tomato, soybean, and sunflower) at 10, 100, 500 and 1000 mg test item/kg dry weight of artificial substrate along with vehicle control to determine test concentrations for the definitive test. Effects of test item were observed on seedling emergence, shoot height, and dry shoot weight on day 14 in all the tested plant species.

Based on the range finding results for each plant species, five test concentrations of test item were tested in main study. There was also adequate number of concurrent control and vehicle control (acetone) group. Seeds of the test species were sown in plastic pots with 2 seeds/pot (corn), 3 seeds/pot (cabbage, tomato, soybean, and sunflower) and 5 seeds/pot (onion). Uniform seeds of the test plant species were sown in chemically inert plastic pots containing the test artificial substrate. Within a given phase of the test, all test plants including the control(s) were from the same source. The plants were grown in non-porous plastic pots with a tray saucer under the pot. The pots were large enough to allow normal growth. A pot was defined as the replicate (diameter: 15.5 cm, surface area about: 189 cm2)

To prepare required test item concentration, required quantity of test item was weighed and mixed with acetone (sonication was made, where essential) followed by introduction into artificial substrate. Vehicle was allowed to dry completely, and this was homogenously mixed using blender. For control, required quantity of artificial substrate was mixed thoroughly with nutrient solution. For vehicle control, required quantity of artificial substrate was mixed with acetone and allowed to dry completely and this was homogenously mixed using blender. After test medium preparation, the pots were filled with uniform quantity of test medium (2 kg). This was followed by addition of required volume (220 mL/pot) of water based on WHCmax (26%) of the artificial substrate.

The concentrations were separated by for of 3 for onion soybean sunflower and tomato, and 2.5 for corn and cabbage. The test concentrations for onion, soybean and sunflower are 15, 45, 135, 405, 1215 mg/kg/dw. For corn and cabbage are 32, 80, 200, 500,1250 mg/kg/dw. For tomato are 5, 15, 45, 135, 405 mg/kg/dw. The experiment was conducted in a special room with PAR lights with light intensity22600 to 24100 Lux, and suitable environmental conditions withair temperature of 19.5 to 23.3 °C and air humidity of 71 to 89 %were provided for plant species. During the experiment, the plants were observed for emergence (every day and then at 7 days interval) and visual phytotoxicity (at 7 and 14 days). The experiment completed on 14 days after the emergence of 50% of the vehicle control seedlings. At the end of the experiment, the number of surviving plants, their height and dry weight were observed. 

Analytical verification of the test medium (test item active ingredient analysis in test medium) was performed using a validated analytical method to determine the test item. The samples from the low, mid and high-test item concentrations were analyzed at the beginning of the test (day 0) along with the control(s). For analysis, required quantity of test medium was sampled on day 0

 

During the observation period, i.e. 14 days after 50% of the control(s) plants have emerged, the plants were observed frequently for emergence and visual phytotoxicity and mortality. At the end of the test, measurement of percent emergence and biomass of surviving plants were recorded, as well as visible detrimental effects on different parts of the plant. The latter include abnormalities in appearance of the emerged seedlings, stunted growth, chlorosis, discoloration, mortality, and effects on plant development. A uniform scoring system for visual injury was used to evaluate the observable toxic responses. The final biomass was measured using final average dry shoot weight of surviving plants, by harvesting the shoot at the soil surface and drying them to constant weight at 60 to 70 ºC. The height of the shoot of surviving plants were measured at the end of the test.

Plant observations on days 7 and 14 recorded normal in control and vehicle control. In certain test item treated groups exhibited visual phytotoxicity (toxic responses) of stunted growth and mortality (except onion, cabbage, and tomato). Effects of test item were observed on seedling emergence, seedling survival (except onion, cabbage, and tomato), shoot height, and dry shoot weight on day 14 in all the tested plant species.

 

Visual assessment is the rating of visual damage based on observations of plant stand, vigour, malformation, chlorosis, necrosis, and overall appearance compared with control(s). Uniform scoring system was used for visual injury to evaluate the observable toxic responses. Plants were observed for severity of the visual phytotoxic effects of test item from the grading scale of 0 to 100 %.

A dose-response relationship was established in terms of a regression equation by using four parameter Model. Different model was used for estimating ECx (EC10, EC20, EC50, EC90) and its confidence limits, where possible. The statistical analysis of the shoot height and shoot weight data was evaluated using licensed copies of SYSTAT Statistical package version 12.0. Data was tested for normality (Shapiro-Wilk test) and homogeneity of variance (Levene’s) before performing further analysis. When data was found as normal and homogeneous, ANOVA was performed, when data was found as non-normal or non-homogeneous, data were transformed, and ANOVA was done on transformed data for overall group comparison. Dunnett’s test was performed for pairwise comparison. Comparison of two group’s mean was done using two-sample t-test.

The present study can be considered valid since, the control(s) satisfies the validity criteria given in the guideline as below.

·     The seedling emergence was at least 90% in all the tested plant species (acceptable criterion: seedling emergence should be at least 70%).

·     The seedlings didn’t exhibited visible phytotoxic effects and the plants exhibited only normal variation in growth and morphology for particular species (acceptable criterion: seedlings do not exhibit visible phytotoxic effects and the plants exhibit only normal variation in growth and morphology for particular species).

·     The mean survival of emerged control(s) seedlings was at least 100% for the duration of the study (acceptable criterion: mean survival of emerged control(s) seedlings should be at least 90% for the duration of the study).

·     Environmental conditions for a particular species was identical and growing media contained the same amount of substrate in all the tested plant species from the same source (acceptable criterion: environmental conditions for a particular species should be identical and growing media should contain the same amount of substrate from the same source)

  Based on the outcomes of definitive test by concerning the emergence, the shoot length, and the dry weight were statistically analyzed to determine the EC10, EC20, EC50, EC90, NOEC and LOEC. The NOEC values based on the emergence, the shoot length, and the dry weight, are 45, 45, 45 (onion), 200, 80, 200 (corn), 200,32,80 (cabbage), 5,15,15 (tomato), 135,15, 135 (soybean) and 405, 15, 15 sunflower.

Toxicity to soli microorganisms

In accordance with column 2 of Annex IX of the REACH regulation, the study does not need to be conducted because direct and indirect exposure of the soil compartment is unlikely considering its use as a flavouring agent and fragrance agent in perfumery, especially in soap perfumes.

 

Toxicity to birds

In accordance with column 2 of Annex IX of the REACH regulation, the study does not need to be conducted because direct and indirect exposure of the soil compartment is unlikely considering its use as a flavouring agent and fragrance agent in perfumery, especially in soap perfumes.

Additional information

Toxicity to soil macroorganisms except arthropods

The toxic effect of test chemical was studied on the earthworm, Eisenia fetida by artificial soil test. the study was conducted in two phases ie., range finding test and definitive test. The artificial soil was used as the substrate which was prepared as per the OECD 222 guidelines. As the test chemical was insoluble, acetone was used as carrier vehicle, simultaneously along with test concentrations both control (deionized water) and vehicle control (acetone) were also studied. Before initiation of the definitive study a range finding test was conducted at concentrations of 0.1, 1, 10, 100, 250, 500 and 1000 mg/kg dry. Based on number of cocoon and juvenile production, the concentrations for the main study was decided as 0.10, 0.18, 0.32, 0.58, 1.04, 1.88, 3.39, 6.11 and 11.00 mg/kg. Adult earthwormswith well-developed clitellum of age ranging from 4.5 to 5 months were exposed for definitive test concentrations with minimum number of 10 test organisms per replicate. The test was conducted for the period of 56 days with 8 replicates in control groups and 4 replicates in exposure groups. After mixing of test chemical with artificial soil at a wide range of test item concentrations in which the adult earthworms were placed for 28 days exposure. The mortality and growth effects of the test item on the adult earthworms were examined after 4 weeks of exposure. The adults are then removed from the soil and effects on reproduction was assessed after a further 4 weeks by counting the number of offspring present in the soil. The reproductive output of the worms exposed to the test item is compared to that of the control(s) to determine the no observed effect concentration (NOEC) / effective concentrations.

There was no mortality of earthworms in control, vehicle control and at the tested concentrations of0.10, 0.18, 0.32, 0.58, 1.04, 1.88, 3.39, 6.11 and 11.00mg/kg on Day 28. The percent mortality of earthworms at 3.0 mg a.i. of reference substance/kg dry soil was 17.5%. No pathological and behavioralsymptomswere observed in adult worms during the test period in the control, vehicle control and treated groups (including reference substance). No statistically significant reduction in body weight was observed in treated groups (except 0.32, 0.58, 1.04, 1.88, 3.39, 6.11 and 11.00 mg/kg dry soil and reference substance test group) as compared with the control or vehicle control.

No pathological and behavioral symptoms were observed in juveniles on Day 56 in the control, vehicle control and treated groups. No statistically significant reduction in juvenile production was observed in treated groups (except 0.32, 0.58, 1.04, 1.88, 3.39, 6.11 and 11.00 mg/kg dry soil and reference substance test group) as compared with the control or vehicle control. Cocoons were not present in any of tested groups and reference substance group. After obtaining all the required necessary outcomes, the generated data was treated for statistical analysis. the average body weights and juvenile production was evaluated using licensed copies of SYSTAT Statistical package version 12.0. Data was tested for normality (Shapiro-Wilk test) and homogeneity of variance (Levene’s) before performing further analysis. When data was found as normal and homogeneous, ANOVA was performed for overall group comparison and Dunnett’s test for pairwise comparison. When data was found as non-normal or non-homogeneous, then Kruskal-Wallis was performed for overall group comparison and Mann-Whitney U test for pairwise comparison. Comparison of means between reference substance group and control group was done using two-sample t-test and Mann-Whitney U test. All analyses and comparisons were evaluated at the 5% (p≤0.05) level.

To ensure the bio-availability of test chemical, the active ingredientof test concentrations of low, mid and high test concentrations ie., 0.10, 1.04 and 11.0 mg/kg dry soil were analysed using GC-MS-MS. All the validity criteria, ie., 1.Each replicate (containing 10 adults) produced minimum of 65 juveniles by the end of the test. 2. The coefficient of variation of reproduction is 4.3%. 3. There was no mortality of the earthworms in the control during the experimental period of 28 days, were met, andReference substance (Carbendazim) group exhibited statistically significant reduction in juvenile production at 3 mg a.i./kg dry soil as compared with the control making study valid.

Upon 28 days exposure there was no mortality in the adult earthworms, resulting LC50 >11mg/kg dry soil. After 56 days of exposure NOEC, LOEC, EC10 and EC50 was determined to be 0.18, 0.32, 0.1942 (0.07098-0.4143) and 1.811 (1.271-2.611). respectively.

 

Toxicity to terrestrial arthropods

In accordance with column 2 of Annex IX of the REACH regulation, the study does not need to be conducted because direct and indirect exposure of the soil compartment is unlikely considering its use as a flavouring agent and fragrance agent in perfumery, especially in soap perfumes.

 

Toxicity to terrestrial plants

The study aimed at evaluating the effect of test item on seedling emergence and seedling growth of 6 terrestrial plants was conducted on 2 monocotyledonous and 4 dicotyledonous species. The test item was mixed into the acid washed quartz sand (artificial substrate/soil which was used as the test medium) and exposed as per test guidelines.

A range finding test was carried out with the plant species (onion, corn, cabbage, tomato, soybean, and sunflower) at 10, 100, 500 and 1000 mg test item/kg dry weight of artificial substrate along with vehicle control to determine test concentrations for the definitive test. Effects of test item were observed on seedling emergence, shoot height, and dry shoot weight on day 14 in all the tested plant species.

Based on the range finding results for each plant species, five test concentrations of test item were tested in main study. There was also adequate number of concurrent control and vehicle control (acetone) group. Seeds of the test species were sown in plastic pots with 2 seeds/pot (corn), 3 seeds/pot (cabbage, tomato, soybean, and sunflower) and 5 seeds/pot (onion). Uniform seeds of the test plant species were sown in chemically inert plastic pots containing the test artificial substrate. Within a given phase of the test, all test plants including the control(s) were from the same source. The plants were grown in non-porous plastic pots with a tray saucer under the pot. The pots were large enough to allow normal growth. A pot was defined as the replicate (diameter: 15.5 cm, surface area about: 189 cm2)

To prepare required test item concentration, required quantity of test item was weighed and mixed with acetone (sonication was made, where essential) followed by introduction into artificial substrate. Vehicle was allowed to dry completely, and this was homogenously mixed using blender. For control, required quantity of artificial substrate was mixed thoroughly with nutrient solution. For vehicle control, required quantity of artificial substrate was mixed with acetone and allowed to dry completely and this was homogenously mixed using blender. After test medium preparation, the pots were filled with uniform quantity of test medium (2 kg). This was followed by addition of required volume (220 mL/pot) of water based on WHCmax (26%) of the artificial substrate.

The concentrations were separated by for of 3 for onion soybean sunflower and tomato, and 2.5 for corn and cabbage. The test concentrations for onion, soybean and sunflower are 15, 45, 135, 405, 1215 mg/kg/dw. For corn and cabbage are 32, 80, 200, 500,1250 mg/kg/dw. For tomato are 5, 15, 45, 135, 405 mg/kg/dw. The experiment was conducted in a special room with PAR lights with light intensity22600 to 24100 Lux, and suitable environmental conditions withair temperature of 19.5 to 23.3 °C and air humidity of 71 to 89 %were provided for plant species. During the experiment, the plants were observed for emergence (every day and then at 7 days interval) and visual phytotoxicity (at 7 and 14 days). The experiment completed on 14 days after the emergence of 50% of the vehicle control seedlings. At the end of the experiment, the number of surviving plants, their height and dry weight were observed. 

Analytical verification of the test medium (test item active ingredient analysis in test medium) was performed using a validated analytical method to determine the test item. The samples from the low, mid and high-test item concentrations were analyzed at the beginning of the test (day 0) along with the control(s). For analysis, required quantity of test medium was sampled on day 0

 

During the observation period, i.e. 14 days after 50% of the control(s) plants have emerged, the plants were observed frequently for emergence and visual phytotoxicity and mortality. At the end of the test, measurement of percent emergence and biomass of surviving plants were recorded, as well as visible detrimental effects on different parts of the plant. The latter include abnormalities in appearance of the emerged seedlings, stunted growth, chlorosis, discoloration, mortality, and effects on plant development. A uniform scoring system for visual injury was used to evaluate the observable toxic responses. The final biomass was measured using final average dry shoot weight of surviving plants, by harvesting the shoot at the soil surface and drying them to constant weight at 60 to 70 ºC. The height of the shoot of surviving plants were measured at the end of the test.

Plant observations on days 7 and 14 recorded normal in control and vehicle control. In certain test item treated groups exhibited visual phytotoxicity (toxic responses) of stunted growth and mortality (except onion, cabbage, and tomato). Effects of test item were observed on seedling emergence, seedling survival (except onion, cabbage, and tomato), shoot height, and dry shoot weight on day 14 in all the tested plant species.

 

Visual assessment is the rating of visual damage based on observations of plant stand, vigour, malformation, chlorosis, necrosis, and overall appearance compared with control(s). Uniform scoring system was used for visual injury to evaluate the observable toxic responses. Plants were observed for severity of the visual phytotoxic effects of test item from the grading scale of 0 to 100 %.

A dose-response relationship was established in terms of a regression equation by using four parameter Model. Different model was used for estimating ECx (EC10, EC20, EC50, EC90) and its confidence limits, where possible. The statistical analysis of the shoot height and shoot weight data was evaluated using licensed copies of SYSTAT Statistical package version 12.0. Data was tested for normality (Shapiro-Wilk test) and homogeneity of variance (Levene’s) before performing further analysis. When data was found as normal and homogeneous, ANOVA was performed, when data was found as non-normal or non-homogeneous, data were transformed, and ANOVA was done on transformed data for overall group comparison. Dunnett’s test was performed for pairwise comparison. Comparison of two group’s mean was done using two-sample t-test.

The present study can be considered valid since, the control(s) satisfies the validity criteria given in the guideline as below.

·     The seedling emergence was at least 90% in all the tested plant species (acceptable criterion: seedling emergence should be at least 70%).

·     The seedlings didn’t exhibited visible phytotoxic effects and the plants exhibited only normal variation in growth and morphology for particular species (acceptable criterion: seedlings do not exhibit visible phytotoxic effects and the plants exhibit only normal variation in growth and morphology for particular species).

·     The mean survival of emerged control(s) seedlings was at least 100% for the duration of the study (acceptable criterion: mean survival of emerged control(s) seedlings should be at least 90% for the duration of the study).

·     Environmental conditions for a particular species was identical and growing media contained the same amount of substrate in all the tested plant species from the same source (acceptable criterion: environmental conditions for a particular species should be identical and growing media should contain the same amount of substrate from the same source)

  Based on the outcomes of definitive test by concerning the emergence, the shoot length, and the dry weight were statistically analyzed to determine the EC10, EC20, EC50, EC90, NOEC and LOEC. The NOEC values based on the emergence, the shoot length, and the dry weight, are 45, 45, 45 (onion), 200, 80, 200 (corn), 200,32,80 (cabbage), 5,15,15 (tomato), 135,15, 135 (soybean) and 405, 15, 15 sunflower.

 

Toxicity to soli microorganisms

In accordance with column 2 of Annex IX of the REACH regulation, the study does not need to be conducted because direct and indirect exposure of the soil compartment is unlikely considering its use as a flavouring agent and fragrance agent in perfumery, especially in soap perfumes.

 

Toxicity to birds

In accordance with column 2 of Annex IX of the REACH regulation, the study does not need to be conducted because direct and indirect exposure of the soil compartment is unlikely considering its use as a flavouring agent and fragrance agent in perfumery, especially in soap perfumes.