الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
Results obtained in the present invesUgatlQ1l
will be discussed from the followirlg view po1n.ts;
adsorption, d01Ulwardmoveme.ut,1eachabll1t7, persistence
an.d metabolism of D1methoate and Fenvalerate
pesticides as well as some factors influencing
their behaviour in differen.t sol1 t7pes
5.1. Adsorption. of Dimethoate an.d Fenva1erate on.
cla7 minerals and soils.
5.1.1. AdsorptiQll mechanismof D1methoate and
Fenva1erete:
With regard to the effect of time on the adsorptiCll1
of Dimethoate 011the different adsorbents IUlder investigation,
results show that increas1n.g the time of contact between Dimeth08te in solutiQll an.d the adsorbent
was followed by the 1n.crease of the amount adsorbed of
Dimeth08te IUlU1 it reached a maximumatter which it
in.4icated an equilibrium; the t1llle required to reach
equi1ibr~UIDcQllditiQll was, 25, 25, 20, 15 an.44
III1ntJtestor bentOll1te. attapulg1te, ca1careOll8 8011.
sandy clay lo~ soil and kaolinite respectively.
Concerning the adsorption mechanismof Fenvalerate
on different adsorbents under investigation; it reached
its equilibrium conditions in few seconds after contact
between Fenvalerate and different adsorbents.
5·1.2. Effect of Dilllethoate and Fenvalerate concentrations
on the rates of their adsorption on different
adsorbents : The amounts of Dimethoate and Fenvalerate adsorbed
per gram adsorbent; i.e.; X/mwas increased by increasing
the concentration until it reached maximum.Langmuir
equation was used to represent the adsorption of
Dimethoate and Fenvalerate, a linear isotherms were
obtained except in case of adsorption of Fenvalerate on
attapulgUe SlId sandy c lay loam soil.
Freundlich equatiOll fitted the adsorption of
Dimethoate and Fenvalerate on all the adsorbants used,
i.e., bantonite, kaolinite, attapulgite, sandy clay
loam soil and calcareous soil, except in case of high concentratiQlls of Fenvalerate on attapulBite (more
than 0.004 molar).
5.1.3. Effect of adsorbent types on adsorption of
Dimet~te and Penyalerate.
!rhe effect of adsorbent types on the adsorptiOll
of the two pesticides showed that the amount of
adsorbed D1methoatewas as follows:
:Bentonite> calcareous soil> sendy clay loam soil > attapulgite> Kaol1.nite; while for Penvslerate it
w••s: attapulgih > Kaol1.nite> bentonite> calcareous
soil > sandy clay loam soil’
5.2. Effect of somefactors on the downwardmovement
and leachi.B8 of D1methate and J.i’envslerate 1.n
soils : 5.2.1. Dillletho-i1te:
5.2.1.1. Effec; at soil tYpe on Dimethoate mobility-
!rhe higher binding of Dimethoate was recorded with
sandy clay loam soil followed by calcareous soil.
!rhe rate at Dimethoate detected on soil was
increased with depth. !rhe amounts of remained D1methoate
in the third layer (10-15 cm) of both sandy clay
loam and calcareous sOils>seCOAdlayer (5-10 em»
top layer (0-5 cm)’
the obtai.lledresults revealed that the greatest
downward movement of Dimethoete occurred with
calcareous soil followed by sandy clay loam soil.
5.2.1.2. Effect of Dimethoate concentration on the
i.Ilsecticidemobility.
The higher the concentration of Dimethoate used,
the higher the allloWltsremsined on soil surface and
the higher the downward movement and vice versa.
The higher leachability of Dimethoate occurred
with the lowest concentration used.
5.2.1.3. ~ffect of water volume on Dimethoate mobility:
The higher the volume of water used.” i:he lower the
binding on soil surface occurred, and the higher the
amoWlts of Dimethoate removed downward through soil
columns.
The higher the volume of water added.1the higher
the leaohability rate obtai.lled.
5.2.2. Fenvalerate:
5.2.2.1. Effect of soil type on Fenvalerate mobility:
With Fenvalerate, it was completely adsorbed on
the top layer of both so~ clay loam and calcareous
sol1s (100%),
~ffect of Fenvalerate concentration on the insecticide mobility.
In the three used concen:trraions(0.1, 0.2 and 0.3g),
the binding on the surface of the top layer (0-5 Col)
amounted 100%.
5.2.2.3. Effect of water volume on Fenvalerste mobilityl i
Increasing the amount of leaching water hed no
influence on the downward movement of Fenvalerate in
soil columns, since 100% of the Fenvalerate remained
on the surface of the top layer.
5.3. Persistence of Dimethoate and Fenvalerate in sandy
clay loam and calcareous soils under laboratory
condi tions.
Concerning the persistence of Dimethoate in the
two tested soils, results indicated thst degradation in
calcareous so11> sandy clay loam so11.
The percentage of recovered Dimethoate amounted
60.22 and 38.71% for sandy clay loam and calcareous
soils respectively after 120 days.
The rate of fenvalerate degradation was higher
in calcareous soil tbaa in sandy clay loam soil.
IJ1creasing the time of exposure after treatment
increased the rete of Fenvalerate degradation·
5.4.Degradatian products of Dimethoate and Fenvalerate
in soils.
5.4.1. Preparation and identification of Dimethoate
metabolit es·
5.4.1.1. HYdrolysis with aqueous sodium ~ydraxide.
Concerning the hydrolysis of Dimethoate using NaOHt
4 compounds were appeared in aLC chromatogram at Rt 120,
216, 288 and 336 sec. The compound at Rt 336 sec.was
seperated using TIC technique and identified as
follows: the emperical formula was found to be C3H.r0SNt
UV spectrum showed maximum absorption at 222 JUD,IR
spectrum is involved. The mass spectrum showed
molecular ion at m/e 105, the GLC chromatogrem showed
Rt at 336 sec.
5.4.1.2. Oxidation at room temperature:
Cool oxidation product using acidic potassium
permenganate was identified as follows: elementary
analysis showed Ct 30.5% ;H, 6.3%; Nt 5.8%; 3,11.0%;
Pt 14.4% and 0,32.0%. , UV spectrum showed maxilllUlD
absorption at 242 nm, IR spectrum was envolved and
mass spectrum showed molecular ion at lII/e.214.
Rt was at 120 sec.
5.4.1.3. Hot oxidation:
Hot oxidation product using acidic potassium
permenganate was identified as follows: UV spectrum
showed maximum absorption at 320, 395 and 415 .om,
IR spectrum was accomplished , mass spectrum showed
molecular ion (M+) at mle. 184 and GLC showed that
Rt was at 288 sec.
5.4.2.Degradation products of D1aethoate in sandy
clay loam aAd calcareous soils:
Dimethoste was metabolised in the two soils to 5 compounds at Rt 36,60, 120,216 and 288 aec ,, another
sixth compound wss found in the extraction of the
calcareous soil at Rt 336 sec.
4.4.3. Degradation products of Fenvalerate in sandy
clay loam and calcareous soils:
Fenvalerate was metabolised in sandy clay loam and calcareous soils to two metabolites at Rt 168 and 456 sec.