Potassium nitrite

Endpoint summary

Description of key information

Hydrolysis

Not applicable for inorganic salts. Potassium nitrite is completely dissociated into ions in water (expert reviewer judgement).

Biodegradation in water

In accordance with column 2 of Annex VII of the REACH regulation, testing for this end point is technically not feasible and does not need to be conducted since the test chemical is inorganic.

Biodegradation in water and sediment

Estimation Programs Interface prediction model was run to predict the half-life in water and sediment for the test chemical. If released in to the environment, 32.3% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of test chemical in water is estimated to be15 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 test chemical 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 0.0688%), indicates that test chemical is not persistent in sediment.

 

Biodegradation in soil

The half-life period of test chemical in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database. If released into the environment, 67.6% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical in soil is estimated to be 30 days (720 hrs). Based on this half-life value of test chemical, 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.

Adsorption / desorption

The adsorption coefficient Koc in soil and in sewage sludge of test chemical was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. The solutions of the test substance and reference substances were prepared in appropriate solvents. A test item solution was prepared by accurately weighing 4 mg of test item and diluted with Acetonitrile up to 10 ml. Thus, the test solution concentration was 400 mg/l. The pH of test substance was 5.4.Each of the reference substance and test substance were analysed by HPLC at 210 nm. After equilibration of the HPLC system, Urea was injected first, the reference substances were injected in duplicate, followed by the test chemical solution in duplicate. Reference substances were injected again after test sample, no change in retention time of reference substances was observed. Retention time tR were measured, averaged and the decimal logarithms of the capacity factors k were calculated. The graph was plotted between log Koc versus log k. The linear regression parameter of the relationship log Koc vs log k were also calculated from the data obtained with calibration samples and therewith, log Koc of the test substance was determined from its measured capacity factor. The reference substances were chosen according to estimated Koc range of the test substance and generalized calibration graph was prepared. The reference substances were Acetanilide, 4-chloroaniline, 4-methylaniline (p-Tolouidine), N-methylaniline, p-toluamide, Aniline, 2,5-Dichloroaniline, 4-nitrophenol, 2 - nitrophenol, 2-nitrobenzamide, 3-nitrobenzamide, Nitrobenzene, 4-Nitrobenzamide, 1-naphthylamine, 1-naphtol, Direct Red 81, Benzoic acid methylester, Carbendazim, Benzoic acid phenylester, Xylene, Ethylbenzene, Toluene, Naphthalene, 1,2,3-trichlorobenzene, Pentachlorophenol, Phenol, N,Ndimethylbenzamide, 3,5-dinitrobenzamide, N-methylbenzamide, Benzamide, phenanthrene, DDT having Koc value ranging from 1.25 to 5.63. The Log Koc value of test chemical was determined to be 2.257± 0.000 dimensionless at 25°C.This log Koc value indicates that the substance has a low sorption to soil and sediment and therefore have moderate migration potential to ground water.

Additional information

Hydrolysis

Not applicable for inorganic salts. Potassium nitrite is completely dissociated into ions in water (expert reviewer judgement).

Biodegradation in water

In accordance with column 2 of Annex VII of the REACH regulation, testing for this end point is technically not feasible and does not need to be conducted since the test chemical is inorganic.

Biodegradation in water and sediment

Estimation Programs Interface prediction model was run to predict the half-life in water and sediment for the test chemical. If released in to the environment, 32.3% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of test chemical in water is estimated to be15 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 test chemical 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 0.0688%), indicates that test chemical is not persistent in sediment.

 

Biodegradation in soil

The half-life period of test chemical in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database. If released into the environment, 67.6% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical in soil is estimated to be 30 days (720 hrs). Based on this half-life value of test chemical, 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.

Adsorption / desorption

The adsorption coefficient Koc in soil and in sewage sludge of test chemical was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. The solutions of the test substance and reference substances were prepared in appropriate solvents. A test item solution was prepared by accurately weighing 4 mg of test item and diluted with Acetonitrile up to 10 ml. Thus, the test solution concentration was 400 mg/l. The pH of test substance was 5.4.Each of the reference substance and test substance were analysed by HPLC at 210 nm. After equilibration of the HPLC system, Urea was injected first, the reference substances were injected in duplicate, followed by the test chemical solution in duplicate. Reference substances were injected again after test sample, no change in retention time of reference substances was observed. Retention time tR were measured, averaged and the decimal logarithms of the capacity factors k were calculated. The graph was plotted between log Koc versus log k. The linear regression parameter of the relationship log Koc vs log k were also calculated from the data obtained with calibration samples and therewith, log Koc of the test substance was determined from its measured capacity factor. The reference substances were chosen according to estimated Koc range of the test substance and generalized calibration graph was prepared. The reference substances were Acetanilide, 4-chloroaniline, 4-methylaniline (p-Tolouidine), N-methylaniline, p-toluamide, Aniline, 2,5-Dichloroaniline, 4-nitrophenol, 2 - nitrophenol, 2-nitrobenzamide, 3-nitrobenzamide, Nitrobenzene, 4-Nitrobenzamide, 1-naphthylamine, 1-naphtol, Direct Red 81, Benzoic acid methylester, Carbendazim, Benzoic acid phenylester, Xylene, Ethylbenzene, Toluene, Naphthalene, 1,2,3-trichlorobenzene, Pentachlorophenol, Phenol, N,Ndimethylbenzamide, 3,5-dinitrobenzamide, N-methylbenzamide, Benzamide, phenanthrene, DDT having Koc value ranging from 1.25 to 5.63. The Log Koc value of test chemical was determined to be 2.257± 0.000 dimensionless at 25°C.This log Koc value indicates that the substance has a low sorption to soil and sediment and therefore have moderate migration potential to ground water.