Terbutylazine

5915-41-3

Active ingredient in herbicides.

White powder.

Flowable waterbased suspension. 
(Gardoprim-neste *) (PESREG)

229.75

Adsorption and desorption of terbutylazine was determined in
five different soils. 
The adsorption and desorption
coefficients and the adsorption constants were determined.

              % organic       adsorption        desorption
soil type       carbon       Ka        Koc         Kd
____________________________________________________________
sand              1.4      2.270     162.143      6.966
sand              0.4      1.112     278.000      8.610
sandy loam        1.2      2.355     196.250      9.840
silty loam        3.4      5.943     174.794     17.378
sandy loam       11.2     25.177     224.795    164.816
_____________________________________________________________
GLP, EPA, (PESREG)

In the soil columns studies (sandy soil and silty loam,
incubated 139 days, and then rainfall 16 days, 12.5 mm daily) of
terbutylazine (27.3 ppm) 8.40 and 6.19 % of the applied
radioactivity were eluted from the soil columns. 
Most of the
aged residues applied to the soil columns were retained in the
top 10 cm layers. 
The main metabolite was
2-chloro-4-amino-6-tert-butylamino-s-triazine (PESREG).

The leaching behaviour of terbutylazine was studied in soil
columns (loamy sand, sand, silty loam and sandy loam). 
The
penetration depth of terbutylazine into the soil profile ranged
between 6 and 12 cm (GLP, EPA) (PESREG).

Slightly soluble in organic solvents:
dimethylformamide          10 %
chlorobenzene               1 %
ethylacetate                4 %
isopranol                   1 %
methylglycolmonoethylether  4 %
n-octanol                 1.4 %
xylene                      1 %
(PESREG)

Photolysis of terbutylazine on soils (dry soil and moist soil)
was studied under artificial sunlight conditions (24hr). 13 and
15% of used herbicide was degraded in dry and moist soil
samples. 
The main extractable degradation product was
2-hydroxy-4-ethylamino-6-tert-butylamino-s-triazine (PESREG).

The half-life of terbutylazine (10 ppm) was >200 days (pH 7,
50°C) and 183 days (pH 7, 70°C) (PESREG).

Hydrolysis, pH 5, 25°C, half-life 63 d; pH 7 - 9, 25°C,
half-life >200 d (Burkhard & Guth 1981).

The half-lives of terbutylazine (5 ppm, at 20°C) have been
calculated to be 8 days (pH 1), 12 days (pH 5), >200 days (pH 7
and 9) and 5 days (pH 13).

Under acidic and basic conditions a direct degradation of
terbutylazine to
2-hydroxy-4-ethylamino-6-tert-butylamino-s-triazine occurred
(PESREG).

The half-life of terbutylazine (10 ppm) was 41 days (pH 5,
30°C), 12 days (pH 5, 50°C) and 82 hours (pH 5, 70°C) (PESREG).

The half-life of terbutylazine (10 ppm) was >200 days (pH 9,
50°C) and 75 days (pH 9, 70°C) (PESREG).

The degradation of terbutylazine (10 ppm) was studied in a silty
loam under aerobic conditions. 
Terbutylazine disappeared with a
half-life of about 88 days. 
The main metabolites were
2-chloro-4-amino-6-tert-butylamino-s-triazine and
2-hydroxy-4-ethylamino-6-tert-butylamino-s-triazine. 
The
formation of 14CO2 was very slow: 1.69% of used herbicide after
225 days (PESREG).

The degradation of terbutylazine (1 ppm) was studied in two
aquatic (river and pond, both contained 1% of sediment) systems.
80.1% (river) and 79.8% (pond) of used terbutylazine were found
after 17.4 weeks of incubation. 
Half-lives (at 25°C) were
calculated to be 579 days (river) and 463 (pond). 
The volatile
degradation product 14CO2 was found 0.9% (river) and 0.4% (pond)
at the end of the experiments (PESREG).

The degradation of terbutylazine in soil (silty clay soil) was
followed under laboratory conditions. 
N-dealkylation and
hydrolysis of the C-2 substituent were the mechanisms for the
degradation of terbutylazine (PESREG).

2-chloro-4-amino-6-tert-butylamino-s-triazine
2-hydroxy-4-ethylamino-6-tert-butylamino-s-triazine
(PESREG)

The bioaccumulation (28d, 20-22°C) and elimination (in flowing,
untreated water 14d) of terbutylazine (0.402 mg/l) by Lepomis
macrochirus was investigated in a dynamic flow-through system.

                      BCF         half-life (hr)
edibles              14.8            16.3
non-edibles          48.6            22.3
whole fish           33.7            19.2
GLP, EPA, PESREG

LC50, 210 mg/kg, 14d, calc., techn., Eisenia foetida
LC50, 230 mg/kg, 14d, graph., techn., Eisenia foetida
(GLP, OECD No 207) (PESREG).

LD50, 0.020 mg/bee, 20hr, feeding test.

LD50, 0.020 mg/bee, 20hr, contact test (PESREG).