Oxalonitrile

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to microorganisms, other

Remarks:

Soil Microorganisms nitrogen transformation for cyanogen

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: OECD 216: Soil Microorganisms: Nitrogen Transformation Test

Deviations:

no

GLP compliance:

yes

Duration:

28 d

Dose descriptor:

other: NH4-N and NO3-N concentrations

Effect conc.:

667 other: mg/kg soil

Conc. based on:

test mat.

Basis for effect:

inhibition of nitrification rate

Remarks on result:

other: The NH4-N concentrations in EDN treated soils were higher than control and alfalfa treatment. The differences were greater than 25%. For NO3-N, there were no difference between control and EDN treated soil. But the NO3-N concentration in alfalfa-amended

Conclusions:

This study was performed to determine the effects of ethanedinitrile on nitrogen transformation by soil microorganisms to comply with the requirements for an ecotoxicology study on plant protection products ‘Effects on soil non-target microorganisms’. The study was conducted according to the OECD-Guideline for the testing of chemicals, Soil Micro-organisms: Nitrogen transformation test, Guideline 216, the OECD guideline for the testing of chemicals.
Cyanogen was applied at the maximum application rate (MAR) of 667 mg kg-1 soil and at 5 times the MAR (3,333 mg kg-1 soil.) The test soil was a sandy loam obtained from a site near the USDA facility of Salinas, CA.
Soil jars were induced with cyanogen in the lab according to the study protocol. All jars were capped with butyl rubber septa. All C2N2 treated jars were ventilated after 24 hours of application. Day 0 samples from jars were extracted immediately after ventilation of fumigants. All the remaining jars were incubated at room temperature ± 20 oC and extracted following 7, 14 and 28 days of incubation. Ammonium nitrogen (NH4-N) and nitrate nitrogen (NO3-N) were measured on 0, 7, 14 and 28 days of extracted samples.
Analytical method performance was monitored by obtaining by duplicating the sample and analysis of reference standard.
The method detection limit for NH4-N and NO3-N was set at 0.05 mg L-1. Laboratory quality control reference samples (15.0 mg ml-1 of NH4-N and 15.0 mg ml-1 of NO3) were analysed concurrently along with samples and blanks. The recoveries for most compounds were within the acceptable range of 80 to 120%. The methods were therefore found acceptable for the use in this study.
The OECD 216 Guideline states in the “INITIAL CONSIDERATIONS” section that “If agrochemicals (e.g. crop protection products, fertilisers, forestry chemicals) are tested, both nitrogen transformation and carbon transformation tests are conducted.” Therefore, the results of the study should be interpreted along with the carbon transformation study.
The results from this study do not reflect total microbial activities. High concentrations of ammonium produced from the degradation of cyanogen can suppress nitrification of ammonium to nitrate. The Carbon transformation study accurately reflects total microbial activities in soil.

Total N transformation is higher in the ethanedinitrile treated soil compared with control soil. Similarly, the total N transformation in alfalfa amended ethanedinitrile soil was higher than alfalfa only treated soil. This shows that Total N transformation occurs at high rate in ethanedinitrile treated soil compared with all other non- ethanedinitrile treated soils.
The total N transformation comprised of both NH4-N and NO3-N concentrations. The NH4-N concentrations in ethanedinitrile treated soils were higher than control and alfalfa treatment. The differences were greater than 25%. For NO3-N, there were no difference between control and ethanedinitrile treated soil. But the NO3-N concentrations in alfalfa-amended soils were higher on days 14 and 28 than all other treatments (control, ethanedinitrile, alfalfa + ethanedinitrile). NO3-N concentrations were the lowest in alfalfa amended with high dose rate of ethanedinitrile, this is due to excess amount of ethanedinitrile (5 times above the recommended dose rate) used in this study that would have formed excess NH4-N toxic to nitrifying bacteria but it will not happen in commercial situation where the soil is treated with the recommended dose rate.
The NH4-N concentration obtained for the control soil and alfalfa-amended soil was negligible but high for all ethanedinitrile-treated soils. NH4-N concentration increased sharply with incubation period for all treated soils.
NO3-N concentrations in alfalfa-amended soils were higher on days 14 and 28 than all other treatments. NO3-N values were lowest for alfalfa-amended soil treated with high levels of ethanedinitrile.
NH4-N concentrations in ethanedinitrile-treated soils increased with increased incubation period. Differences between the controls and all ethanedinitrile-treated soils were greater than 25%. These results indicate that the addition of ethanedinitrile to soil reacts with water and forms additional NH4N.
For NO3-N, however, there were no differences between the control soils and the ethanedinitrile-treated soil until day 14. Maximum recovery of nitrogen transformation occurred in the alfalfa treated soil without ethanedinitrile. The alfalfa-amended ethanedinitrile-treated soil showed much less recovery of NO3-N. However, NO3-N concentrations in alfalfa-amended soils were higher on days 14 and 28 than all other treatments (control, ethanedinitrile, and alfalfa + plus ethanedinitrile). NO3-N concentrations were the lowest in alfalfa amended with high rate of ethanedinitrile due to excess amount of ammonium produced from the degradation of ethanedinitrile (5 times above the recommended dose rate) used in this study.

Executive summary:

This study was performed to determine the effects of ethanedinitrile on nitrogen transformation by soil microorganisms to comply with the requirements for an ecotoxicology study on plant protection products ‘Effects on soil non-target microorganisms’. The study was conducted according to the OECD-Guideline for the testing of chemicals, Soil Micro-organisms: Nitrogen transformation test, Guideline 216, the OECD guideline for the testing of chemicals. Cyanogen was applied at the maximum application rate (MAR) of 667 mg kg^-1soil and at 5 times the MAR (3,333 mg kg^-1soil.) The test soil was a sandy loam obtained from a site near the USDA facility of Salinas, CA. Soil jars were induced with cyanogen in the lab according to the study protocol. All jars were capped with butyl rubber septa. All C₂N₂treatedjars were ventilated after 24 hours of application. Day 0 samples from jars were extracted immediately after ventilation of fumigants. All the remaining jars were incubated at room temperature ± 20^oC and extracted following 7, 14 and 28 days of incubation. Ammonium nitrogen (NH₄-N) and nitrate nitrogen (NO₃-N) were measured on 0, 7, 14 and 28 days of extracted samples. Analytical method performance was monitored by obtaining by duplicating the sample and analysis of reference standard. The method detection limit for NH₄-N andNO₃-N was set at 0.05 mg L^-1. Laboratory quality control reference samples (15.0 mg ml^-1of NH₄-N and 15.0 mg ml^-1of NO₃) were analysed concurrently along with samples and blanks. The recoveries for most compounds were within the acceptable range of 80 to 120%. The methods were therefore found acceptable for the use in this study. The OECD 216 Guideline states in the “INITIAL CONSIDERATIONS” section that “If agrochemicals (e.g. crop protection products, fertilisers, forestry chemicals) are tested, both nitrogen transformation and carbon transformation tests are conducted.” Therefore, the results of the study should be interpreted along with the carbon transformation study. The results from this study do not reflect total microbial activities. High concentrations of ammonium produced from the degradation of cyanogen can suppress nitrification of ammonium to nitrate. The Carbon transformation study accurately reflects total microbial activities in soil.

 

Total N transformation is higher in theethanedinitriletreated soil compared with control soil. Similarly, the total N transformation in alfalfa amendedethanedinitrilesoil was higher than alfalfa only treated soil. This shows that Total N transformation occurs at high rate inethanedinitriletreated soil compared with all other non-ethanedinitriletreated soils.

The total N transformation comprised of both NH₄-N and NO₃-N concentrations. The NH4-N concentrations inethanedinitriletreated soils were higher than control and alfalfa treatment. The differences were greater than 25%. For NO₃-N, there were no difference between control andethanedinitriletreated soil. But the NO₃-N concentrations in alfalfa-amended soils were higher on days 14 and 28 than all other treatments (control,ethanedinitrile, alfalfa +ethanedinitrile). NO₃-N concentrations were the lowest in alfalfa amended with high dose rate ofethanedinitrile, this is due to excess amount ofethanedinitrile(5 times above the recommended dose rate) used in this study that would have formed excess NH4-N toxic to nitrifying bacteria but it will not happen in commercial situation where the soil is treated with the recommended dose rate.

The NH₄-N concentration obtained for the control soil and alfalfa-amended soil was negligible but high for all ethanedinitrile-treated soils. NH₄-N concentration increased sharply with incubation period for all treated soils.

NO₃-N concentrations in alfalfa-amended soils were higher on days 14 and 28 than all other treatments. NO₃-N values were lowest for alfalfa-amended soil treated with high levels of ethanedinitrile. 

NH₄-N concentrations in ethanedinitrile-treated soils increased with increased incubation period. Differences between the controls and all ethanedinitrile-treated soils were greater than 25%. These results indicate that the addition of ethanedinitrile to soil reacts with water and forms additional NH₄N.

For NO₃-N, however, there were no differences between the control soils and the ethanedinitrile-treated soil until day 14. Maximum recovery of nitrogen transformation occurred in the alfalfa treated soil without ethanedinitrile. The alfalfa-amended ethanedinitrile-treated soil showed much less recovery of NO₃-N. However,NO₃-N concentrations in alfalfa-amended soils were higher on days 14 and 28 than all other treatments (control, ethanedinitrile, and alfalfa + plus ethanedinitrile). NO₃-N concentrations were the lowest in alfalfa amended with high rate of ethanedinitrile due to excess amount of ammonium produced from the degradation of ethanedinitrile (5 times above the recommended dose rate) used in this study.

Reference 2

Endpoint:

toxicity to microorganisms, other

Remarks:

Soil Microorganism-nitrogen Transformation for Cyanogen (C2N2)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: OECD 216: Soil Microorganisms: Nitrogen Transformation Test

GLP compliance:

yes

Key result

Duration:

90 d

Dose descriptor:

other: NH4-N and NO3-N concentrations

Effect conc.:

667 other: mg/kg soil

Conc. based on:

test mat.

Basis for effect:

inhibition of nitrification rate

Conclusions:

The Addendum lists the NH4-N and NO3-N concentrations in soil after 90 days. Nitrogen transformation results are shown for NH4-N and NO3-N, respectively, for 90 days compared to 28 days of incubation. These results show that the amount of NO3-N mineralized in the alfalfa-treated soils was identical to the amount of NO3-N mineralized in the alfalfa plus ethanedinitrile-treated soils. Although most of the NH4-N in the ethanedinitrile treatments was mineralized within 90 days, a small amount of nitrate was extracted possibly due to immobilization of the mineralized NO3-N by soil microorganisms. This study shows that ethanedinitrile has no long-term effect on microbial activities involved in N transformations in soil.

Executive summary:

The Addendum lists the NH4-N and NO3-N concentrations in soil after 90 days. Nitrogen transformation results are shown for NH4-N and NO3-N, respectively, for 90 days compared to 28 days of incubation. These results show that the amount of NO3-N mineralized in the alfalfa-treated soils was identical to the amount of NO3-N mineralized in the alfalfa plus ethanedinitrile-treated soils. Although most of the NH4-N in the ethanedinitrile treatments was mineralized within 90 days, a small amount of nitrate was extracted possibly due to immobilization of the mineralized NO3-N by soil microorganisms. This study shows that ethanedinitrile has no long-term effect on microbial activities involved in N transformations in soil.

Description of key information

This study was performed to determine the effects of ethanedinitrile on nitrogen transformation by soil microorganisms to comply with the requirements for an ecotoxicology study on plant protection products ‘Effects on soil non-target microorganisms’. The study was conducted according to the OECD-Guideline for the testing of chemicals, Soil Micro-organisms: Nitrogen transformation test, Guideline 216, the OECD guideline for the testing of chemicals.

Cyanogen was applied at the maximum application rate (MAR) of 667 mg kg-1 soil and at 5 times the MAR (3,333 mg kg-1 soil.) The test soil was a sandy loam obtained from a site near the USDA facility of Salinas, CA.

Soil jars were induced with cyanogen in the lab according to the study protocol. All jars were capped with butyl rubber septa. All C2N2 treated jars were ventilated after 24 hours of application. Day 0 samples from jars were extracted immediately after ventilation of fumigants. All the remaining jars were incubated at room temperature ± 20 oC and extracted following 7, 14 and 28 days of incubation. Ammonium nitrogen (NH4-N) and nitrate nitrogen (NO3-N) were measured on 0, 7, 14 and 28 days of extracted samples. 

Analytical method performance was monitored by obtaining by duplicating the sample and analysis of reference standard. 

The method detection limit for NH4-N and NO3-N was set at 0.05 mg L-1. Laboratory quality control reference samples (15.0 mg ml-1 of NH4-N and 15.0 mg ml-1 of NO3) were analysed concurrently along with samples and blanks. The recoveries for most compounds were within the acceptable range of 80 to 120%. The methods were therefore found acceptable for the use in this study.

The OECD 216 Guideline states in the “INITIAL CONSIDERATIONS” section that “If agrochemicals (e.g. crop protection products, fertilisers, forestry chemicals) are tested, both nitrogen transformation and carbon transformation tests are conducted.” Therefore, the results of the study should be interpreted along with the carbon transformation study.

The results from this study do not reflect total microbial activities. High concentrations of ammonium produced from the degradation of cyanogen can suppress nitrification of ammonium to nitrate. The Carbon transformation study accurately reflects total microbial activities in soil.

 

Total N transformation is higher in the ethanedinitrile treated soil compared with control soil. Similarly, the total N transformation in alfalfa amended ethanedinitrile soil was higher than alfalfa only treated soil. This shows that Total N transformation occurs at high rate in ethanedinitrile treated soil compared with all other non- ethanedinitrile treated soils.

The total N transformation comprised of both NH4-N and NO3-N concentrations. The NH4-N concentrations in ethanedinitrile treated soils were higher than control and alfalfa treatment. The differences were greater than 25%. For NO3-N, there were no difference between control and ethanedinitrile treated soil. But the NO3-N concentrations in alfalfa-amended soils were higher on days 14 and 28 than all other treatments (control, ethanedinitrile, alfalfa + ethanedinitrile). NO3-N concentrations were the lowest in alfalfa amended with high dose rate of ethanedinitrile, this is due to excess amount of ethanedinitrile (5 times above the recommended dose rate) used in this study that would have formed excess NH4-N toxic to nitrifying bacteria but it will not happen in commercial situation where the soil is treated with the recommended dose rate.

The NH4-N concentration obtained for the control soil and alfalfa-amended soil was negligible but high for all ethanedinitrile-treated soils. NH4-N concentration increased sharply with incubation period for all treated soils.

NO3-N concentrations in alfalfa-amended soils were higher on days 14 and 28 than all other treatments. NO3-N values were lowest for alfalfa-amended soil treated with high levels of ethanedinitrile. 

NH4-N concentrations in ethanedinitrile-treated soils increased with increased incubation period. Differences between the controls and all ethanedinitrile-treated soils were greater than 25%. These results indicate that the addition of ethanedinitrile to soil reacts with water and forms additional NH4N.

For NO3-N, however, there were no differences between the control soils and the ethanedinitrile-treated soil until day 14. Maximum recovery of nitrogen transformation occurred in the alfalfa treated soil without ethanedinitrile. The alfalfa-amended ethanedinitrile-treated soil showed much less recovery of NO3-N. However, NO3-N concentrations in alfalfa-amended soils were higher on days 14 and 28 than all other treatments (control, ethanedinitrile, and alfalfa + plus ethanedinitrile). NO3-N concentrations were the lowest in alfalfa amended with high rate of ethanedinitrile due to excess amount of ammonium produced from the degradation of ethanedinitrile (5 times above the recommended dose rate) used in this study.

 

The Addendum lists the NH4-N and NO3-N concentrations in soil after 90 days. Nitrogen transformation results are shown for NH4-N and NO3-N, respectively, for 90 days compared to 28 days of incubation. These results show that the amount of NO3-N mineralized in the alfalfa-treated soils was identical to the amount of NO3-N mineralized in the alfalfa plus ethanedinitrile-treated soils. Although most of the NH4-N in the ethanedinitrile treatments was mineralized within 90 days, a small amount of nitrate was extracted possibly due to immobilization of the mineralized NO3-N by soil microorganisms. This study shows that ethanedinitrile has no long-term effect on microbial activities involved in N transformations in soil.