pH (ppm) (°C) (days)
The major hydrolysis products were
pH 4, 7 and 9 benzazimide and!or hydroxymethyl benzazimide; bis-fbenzazim ide-N-methyl) suifide;
pH 4 and 7 mercaptomethyl benzazimide;
pH 7 and 9 anthranilic acid.
(PESREG)
124 Environment Guide 71
Azinph
Hydrolysis in acid The half-Iife ot azinophos-methyl was 38.9 days (30 C) and 87 days (caIc.) (22 °C) at pH 4. (PESREG)
Hydrolysis in base The half-Iife of azinophos-methyl was 2.2 days (30 °ID) and 4.1 days (calc.) (22 °C) at pH 9. (PESREG)
HaIf-Iife n water, days 12.8 pH 8.8,20 °C (de Heer 1979) 55 pH 7.6, 20 °C (de Heer 1979)
Aerobic degradation in soil The degradation behaviour of azinphos-methyl was studied in the laboratory under aerobic conditions withtwosolis. After an incubation period of 30 days about 6.8—8.6% ot applied active ingredient could be extracted from the solls.
After92 days the proportion of parent compound was about 4.6—6.2%. The fol Iowing degradation products were detected: desmethyl azinphos-methyl;
hydroxymethyl benzazimide/benzaztmide; methylsulfinyl-methyl-benzazimide;
methylsulfonyl-methyl benzazimide; methyl benzazimide sulfonic acid. (PES REG)
The degradation of azinphos-methyl was investigated in sandy loam soil under aerobic conditions. The degradation rate of azinphos-methyl did not follow strictly first order kinetics over the 365 day period. A half-Iife value can be esti mated for azinphos-methyl through 95% degradation and was shown to be 44 days. The degradation products were azinphos-methyl oxygen analog, mercap tomethyl benzazimide, benzazimide and/or hydroxymethyl benzazimide and bis methyl benzazimide suifide. (PESREG)
The hait-life of azinphos-methyl in sterile soil (sandy loam soil) was 355 days.
(PESREG)
The degradation of azinphos-methyl was studied in the laboratory tests ontwo different sos. Approx.19—9°Ioot the C-14 activity applied was eliminated as 1 4C02 222—552 days after application ot (carbonyl-C-1 4) azinphos-methyl. Also the degradation of (phenyl-UL-C-14) azinphos-methyl was studied in the soi!.
Approx. 10% oftheapplied C-14 activity was eliminated as 14C02 365 days aifer application. (PESREG)
Anaerobic degradation rn soil The hait-lite ot azinphos-methyl under anaerobic soil (sandy loam soil) condi tions was 68 days following 30 days in aerobic soiL No additional metabolites were formed under anaerobic conditions. (PESREG)
Degradation and Azinphos-methyl oxygen anaog;
transformation products Benzazimide and/or hydroxymethyl benzazimide;
bis-(benzazimide-N-methyl) sultide;
mercaptomethyl benzazimide;
anthranilic acid.
Other information about The major metabollc pathway in the degradation of azinphos-methyl is hydroly degradation sis ot the phosphorous ester resulting in mercaptomethyl benzazimide or
hydroxymethyl benzazimide and their dimethyl (mono or di) thiophosphoric acids. Minor metabolic pathways are 1) oxidative desulturization with formation ot azinphos-methyl oxygen analog, 2) hydrolysis of the phosphorous-methoxy group to yield either desmethyl azinphos-methyl or desmethyl oxygen analog and 3) isomerization of the methoxy-oxygen and phosphorothiono-sulfur to ulti mately give the desmethyl azinphos-methyl S-methyl isomer; further degrada tion ot these products occurs by hydrolysis ot the phosphorous ester linkage between the phosphorus and the benzazimide moiety. Azinphos-methyl oxygen analog is the only metabolite/degradation product which exhibits cholinest erase inhibition activity. Azinphos-methyl itseit shows only slight activity.
(PESREG)
Bioconcentration
factor,
60 appr. 60, exposure 15 ppb, 28dfishes lctalurus punctatus (PESREG)
Environment Guide 71 125
Azinph
LD5O values to mammais in oral exposure, mglkg
LD5O values to mammais in non-oral exposure, mglkg
LC5O values to mammais in inhalation exposure, mglm3
Other information about mammais
Carcinogenicity
LD5O values to birds in oral exposure, mg/kg
NOEC values to birds in oral exposure, mg/kg
Effects on the reproduction ot birds
Other information about birds
11 orl-rat (Lewis & Sweet 1984) 80 orl-gpg, male (Martin 1968) 13—16.4 orl-rat(Anon. 1976) 4.4—4.6 ori-rat
>10 on-dag
6.7 ori-rat male not ted 12.8 ori-rat male ted 15.5 ori-rat male 9.1 oni-rat male not fed 17.25 ori-rat male fed 25.4 orl-rat male 12.2—15 ori-rat female 10—19 onl-rat 5.6 onl-rat male 6.4 oni-rat temale
(PESREG)
58 ori-rat male, Gusation* 53 oni-rat female, Gusation*
(PESREG)
65 skn-mus
220 skn-rat
(Lewis & Sweet) 220 skn-rat (Anon. 1976) 200—250 idr-rat male 155 idr-ratfemale
(PESREG)
8.5—8.9 ipr-rat female (PESREG) 155 4hr, ihl-rat male
132 4hr, ihl-rat temale 396 lhr, ihi-rat male 310 1 hr, ihi-nat female
(PESREG)
In diet; no montality occurred in rats fed 1 mg/kglday for 60 days (Martin 1968).
NCI cancinogenesis bioassay completed: results indefinite, rat;
results negative, mus (Lewis & Sweet 1984).
136 onl-dck
277 onl-ckn
(Lewis & Sweet 1984) 8.00—8.50 orl-Agelaius phoeniceus 27 onl-Sturnus vuiganis
(Schafen et al. 1983)
32 14d, onl-Colinus virginianus, GLP (PESREG) 5.6 NOEL, 14d, Colinus virginuanus, GLP (PESREG) 12 20w-diet,Anas platyrhyncos, GLP (PESREG)
The no-reproduction-effect concentration is 35 ppm, 20 week-dietAnas platy rhyncos. There was apparent treatment-related decrease in the percent hatched, 101 ppm, 20 week-diet,Anas platynhyncos.GLP (PESREG) LOEC is 35 ppm based on the decresed body weight gains of the aduit Anas platyrhyncos in 20 week-diet. GLP (PESREG)
126 Environment Guide 71
Azinph Effects on invertebrates LC5O, 59 mg/kg, 14d, Eisenia foetida, OECD No 207
LLC, 32 mg/kg, 14d Eisenia foetida, OECD No 207 NOEC, 1 mg/kg, 14d, Eisenia foetida, OECD No 207 (PESREG)
Effects on bees LD5O, 0.000063 mg/bee, 460 g a.i./ha (Smart & Stevenson 1982) LD5O, 0.000423 mg/bee, 48hr, at 26.7 °C (Atkins & Anderson 1967) Effects on arthropods Pteronarcys dorsata:
D.0211 mg/I, 96hr LC5O; 0.0049 mg/I, 30d LC5O Acroneuria Iycorias:
0.0015 mg!I, 30d LC5O; 0.00136 mg/I, 30 day, no effect Ophiogomphus rupinsulensis:
0.07 2 mg/I, 96hr LC5O; 0.0022 mg/I, 30d LC5O;
0.001 73 mg/I, 30d, no effect Hydropsyche beifoni:
0.0074 mg/I, 30d LC5O; 0.00494 mg/I, 30d no effect Ephemerella subvaria:
0.0045 mg/l, 30d LC5O; 0.0025 mg/l, 30d, no effect (Verschueren 7983).
Pteronarcys californica: 0.007 5 mg/I, 96hr LC5O (Sanders & Cope 1968).
Effeots on microorganisms Significant differences were recognized on soil respiration between azinphos methyl treated and untreated soil:
soi! mgazinphos- days solI
methyl after respiration
1kg in treat- signilicant
soi! ment difference
carbon dioxide LOAMY SAND
without Iucerne-grass 1.07 7 +
10.67 7 ÷
7.07 14 ÷
10.67 21 +
with lucerne-grass 1.07 7 +
1.07 14 +
10.67 14 ÷
1.07 21 +
10.67 21 +
SANDY SILT
without lucerne-grass 1 0.67 7 +
1.07 14 ÷
1D.67 14 +
with Iucerne-grass 7.07 21 +
(PESREG)
Environment Guide 71
-127
Azinph
Signiticant differences in mineralization of nitrogen were observed between azinphos-methyl treated and controi soil sampies:
mg azinphos- days significant
methyl after difference
soil 1kg in treat
soi! ment ammonium nitrate
loamy sand 1.07 0 ÷ +
sandysNt 1.07 14 +
10.67 14 ÷
10.67 42 ÷
loamy sand after 1.07 21 + +
amendmentwith 10.67 21 + +
ammonium 1.07 28 +
10.67 28 +
sandysiltafier 1.07 0 +
amendmentwith 10.67 0 +
ammomium 1.07 14 ÷ +
10.67 56 + +
(PESREG)
Azinphos-methyl (at 2 to 10000 ppm) did not inhibit the bacteria and actino mycetes, but it (at 2 to 10 ppm) caused 4 to 18% inhibition ot the four fungi (Aspergillus niger, Penicillium daleae, Irichoderma viride and Phycomyces nitens). (PESREG)
EC5O values to algae,mgII 3.61 96hr, EbC5O, grw ihb 7.15 96hr, ErC50, grw ihb
Scenedesmus subspicatus OECD No 201 (PESREG) LC5O values to crustaceans, 0.00019 Daphnia magna)
mg/I 0.00019 act, Daphnia pulex
(Frear et al. 1967 0.00015 96 hr, Gammarus lacustris 0.0001 96 hr, Gammarus fasciatus
(Sanders 1969)
0.00016 20 d, Palaemonetes kadiakensis 0.021 96 hr, Asellus brevicaudus 0.0032 act, Daphnia pulex
0.0012 120 hr, Palaemonete kadiakensis fKenaga 1979)
0.0011 48hr, Daphnia magna (PESREG) 0.0003 48hr, Mysidopsis bahia, GLP (PESREG) 0.00022 96hr, Mysidopsis bahia, GLP (PESREG) 0.0001 96hr, Gammarus tasciatus
0.021 96hr, Asellus Brevicaudus (de Heer 1979)
128 Environment Guide 71