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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Endpoint:
other distribution data
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions

Data source

Reference
Reference Type:
review article or handbook
Title:
Dissipation and phytotoxicity of sodium azide in soil.
Author:
Ketchersid M.L., Merkle M.G.
Year:
1976
Bibliographic source:
Weed Science 24: 312-315.
Report date:
1976

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 312 (Leaching in Soil Columns)
Deviations:
yes
Remarks:
: no reference substance, only 1 soil, lower amount of artificial rain applied
GLP compliance:
no
Type of study:
soil leaching
Media:
water - soil

Test material

Constituent 1
Chemical structure
Reference substance name:
Sodium azide
EC Number:
247-852-1
EC Name:
Sodium azide
Cas Number:
26628-22-8
Molecular formula:
N3Na
IUPAC Name:
sodium azide

Results and discussion

Any other information on results incl. tables

There was no difference in leaching pattern when leaching the equivalent of 112 kg/ha of Sodium azide through soil with pH values of 5.5 and 8.0; in both cases almost 50 % of the azide remained in the top 2.5 cm and almost 75 % remained in the top 5.0 cm (Table 1). The azide did not move as a band with the water front but gradually spread into the soil with the water. All of the herbicide applied to alkaline soil could be accounted for while 15.7 % was lost in the acid soil presumably due mainly to vapor losses.

 

Table 1. Percentages of Sodium azide recovered at various depths of Lufkinfine sandy loam soil 1 hr after surface application of 112 kg/ha followed by a 1.3 cm simulated rainfall.

Section analyzed (cm)

Soil pH

5.5

8.0

0.0-2.5

45.4  a

47.6  a

2.5-5.0

26.7  b

26.4  b

5.0-7.6

9.4 cd

16.7 be

7.6-10.2

2.1 cd

7.3 cd

10.2-12.7

0.6  d

2.5 cd

12.7-15.2

0.1  d

0.8  d

total detected

84.3

101.3

Values followed by the same letter are not significantly different at the 1 % level using Duncan's multiple range test.

 

Applicant's summary and conclusion

Conclusions:
The degree of leaching was not affected by pH.
Executive summary:

Sodium azide is used as a non-selective, broad spectrum herbicide effective against both annual and perennial weeds. The biological activity of azides has been shown to arise from liberation of undissociated hydrazoic acid, which is dependent on soil pH. This study was conducted to compare the degree of leaching of sodium azide applied as 15 % granular formulation from acid and alkaline soil.

The results show no difference in leaching pattern when leaching the equivalent of 112 kg/ha of Sodium azide through soil with pH values of 5.5 and 8.0; in both cases, almost 50 % remained in the top 2.5 cm and almost 75 % in the top 5 cm. All of the Sodium azide applied to alkaline soil could be recovered while 15.7 % were lost in the acid soil. This was ascribed to vapor losses of Sodium azide after hydrolysis to hydrazoic acid.