Ammonia, anhydrous

Toxicity to soil macroorganisms except arthropods

Link to relevant study record(s)

Reference

Endpoint:

toxicity to soil macroorganisms except arthropods: long-term

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Principles of method if other than guideline:

no details provided

GLP compliance:

not specified

Duration:

52 wk

Dose descriptor:

NOEC

Effect conc.:

140 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other:

Remarks on result:

other: number of nematods

Remarks:

Inorganic fertilizers containing ammoniacal nitrogen or formulations releasing this form of N in the soil are most effective for suppressing nematode populations. Anhydrous ammonia has been shown to reduce soil populations of Tylenchorhynchus claytoni, Helicotylenchus dihystera, and Heterodera glycines. The rates required to obtain significant suppression of nematode populations are generally in excess of 150 kg N/ha.

Details on results:

Inorganic fertilizers containing ammoniacal nitrogen or formulations releasing this form of N in the soil are most effective for suppressing nematode populations. Anhydrous ammonia has been shown to reduce soil populations of Tylenchorhynchus claytoni, Helicotylenchus dihystera, and Heterodera glycines. The rates required to obtain significant suppression of nematode populations are generally in excess of 150 kg N/ha.

This amount corresponds to 182.4 kg NH3/ha.

Calculation of the sensitivity of nematods

182.4 kg NH3/ha/year

182.4 kg NH3
182400 g NH3
182400000 mg NH3


ha=> m2 10000 m2
upper 10 cm 1000 m3
1000000 L

CALCULATION OF THE DENSITY OF DRY SOIL
RHOsoil from equation 10-5 from "Guidance on information requirements and chemical safety assessment Chapter R.10: Characterisation of dose [concentration]-response for environment, page 40, (2008)" 1.15 kg/dm³ wet soil
1.15 g/cm³
The conversion from wet soil to dry soil was performed according of the Technical Guidance on Risk Assessment Part II published by the European Chemicals Bureau 2003. The calculation was performed using equation 82b (page 132) with the supporting information from Table 5 (page 43) and equation 18 (page 44). A conversion a factor of 1.13 kg wet soil/kg dry soil was calculated. 1.13 kg wet soil/kg dry soil
Resulting factor 1.2995 kg/dm³ dry soil

This value is confirmed by https://hypersoil.uni-muenster.de/0/05/01.htm
"Ein humoser Oberboden hat ein Raumgewicht von 1,3 g/cm³. Ein entsprechender Bodenhorizont von 10 cm Mächtigkeit hat dementsprechend ein Raumgewicht von 130 kg/m² (1,3 g x 100 cm x 100 cm x 10 cm). "


specific weight 1.2995 kg dw/dm³

1299500 kg dw/ha in top 10 cm

140.3616776 mg NH3 /kg dw/year

Description of key information

The rates required to obtain significant suppression of nematode populations are generally in excess of 150 kg N/ha. This amount corresponds to 182.4 kg NH3/ha. This demonstrates that soil macroorganisms are not sensitive to anhydrous ammonia. Furthermore, ammonia applied directly to the soil is converted to other forms by bacteria in the nitrate cycle.

There is further information (Klimisch 3) which indicates that the long-term effect (determined 9 month after one application corresponding to 52.42 mg NH3/kg dw) on earthworms and cocoons is minor.

Key value for chemical safety assessment

Long-term EC10, LC10 or NOEC for soil macroorganisms:

52.42 mg/kg soil dw

Additional information

The rates required to obtain significant suppression of nematode populations are generally in excess of 150 kg N/ha. This amount corresponds to 182.4 kg NH3/ha. This demonstrates that soil macroorganisms are not sensitive to anhydrous ammonia. Furthermore, ammonia applied directly to the soil is converted to other forms by bacteria in the nitrate cycle.

There is further information (Klimisch 3) which indicates that the long-term effect (determined 9 month after one application corresponding to 52.42 mg NH3/kg dw) on earthworms and cocoons is minor.