EPA-600/9-78-003
February 1978
SYMPOSIUM ON ENVIRONMENTAL
TRANSPORT AND TRANSFORMATION OF PESTICIDES
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
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The nine series are:
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This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/9-78-003
February 1978
SYMPOSIUM
ON
ENVIRONMENTAL TRANSPORT AND TRANSFORMATION OF PESTICIDES
JOINT U.S.-U.S.S.R. PROJECT 02.03-31
"FORMS AND MECHANISMS BY WHICH PESTICIDES AND CHEMICALS ARE TRANSPORTED"
S. G. Malakhov, Co-Chairman, U.S.S.R. Side
David W. Duttweiler, Co-chairman, U.S. Side
ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U. S. ENVIRONMENTAL PROTECTION AGENCY
ATHENS, GEORGIA 30605
For tmle by the Superintendent of Documents, U.S. Government
Printing Office, Weihington. D.C. 20402
-------
DISCLAIMER
This report has been reviewed by the Environmental Research Laboratory,
U. S. Environmental Protection Agency, Athens, Georgia, and approved for
publication. Approval does not signify that the contents necessarily reflect
the views and policies of the U. S. Environmental Protection Agency, nor does
mention of trade names or commercial products constitute endorsement or
recommendation for use.
ii
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FOREWORD
Cooperation and exchange of scientific information under the US-USSR
Agreement on Cooperation in the Field of Environmental Protection has helped
both countries in their efforts to control environmental pollution. Begun
in 1972, the Agreement was extended for a second 5-year period by the Co-
Chairmen of the Joint US-USSR Committee—Mr. Douglas M. Costle, Administrator
for the U.S. Environmental Protection Agency, and Academician Yuri Z. Izrael,
Chief of the Main Administration of the Hydrometeorological Service.
Among several working groups and projects established under this
Agreement is Project 02.03-31, "Forms and Mechanisms by Which Pesticides and
Chemicals are Transported in Soil, Water, and Biota." The agreed objective
of this project is "mutually beneficial cooperation that will aid in the
solution of environmental problems associated with the migration of pesticides
and chemical substances used in agriculture." Responsibility for US participa-
tion in the joint project was assigned to the undersigned in 1974. Members
of this project and invited experts from government research organizations,
academia, and private industry from the two countries have since exchanged
visits on several occasions. This document records the extended abstracts of
papers presented at a project symposium, which was held in October 1976 in
Tbilisi, USSR, to exchange current scientific information on the environmental
movement and transformation of agricultural pesticides.
David W. Duttweiler
Director
Environmental Research Laboratory
Athens, Georgia
111
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ABSTRACT
Under the USA-USSR Agreement on Cooperation in the Field of Environmental
Protection, a joint project committee on environmental transport of agricultural
chemicals (pesticides and fertilizers) sponsored a symposium on 20-27 October
1976 in Tbilisi, USSR. Papers were presented by American and Soviet scientists
on the movement and transformations of pesticides in the atmosphere, in soils,
in water, in plants, and in animals, and on the use of mathematical modeling
to describe the transport and transformation of pesticides in the environment.
Twenty-six papers encompassed reviews of the state of the art in each country
and results of research on particular aspects of the topics.
iv
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CONTENTS
Foreword iii
Abstract iv
Introduction viii
Pesticide Movement and Transformation in the Atmosphere
Co-Chairmen: D. G. Crosby (USA) and S. G. Malakhov (USSR)
Atmospheric Transport and Transformation of Pesticides 1
D. G. Crosby, University of California
Atmospheric Transport of DDT 11
V. A. Borzilov, S. G. Malakhov, and A. I. Osadchii,
Institute of Experimental Meteorology; V. M. Koropalov
and I. M. Nazarov, Institute of Applied Geophysics
Disparlure and Some Juvenile Hormone Analogue Persistence
in the Environment 21
F. P. Waintraub, G. F. Vylegzhanina, L. L. Chernichuk,
and I. A. Konjukhova, All-Union Institute for
Biological Methods of Plant Protection
Pesticide Transport and Transformation in Soil
Co-Chairmen: D. D. Kaufman (USA) and M. S. Sokolov (USSR)
Predicting and Simulating Pesticide Transport from Agricultural
Land: Mathematical Model Development and Testing 30
G. W. Bailey and H. P. Nicholson, U. S. Environmental
Protection Agency
General Laws of the Migration of Pesticide Residues in the
Delta Landscape under Irrigation 38
M. S. Sokolov, Institute of Agrochemistry and Soil
Science of the USSR Academy of Sciences
Certain Laws of Organochlorine Pesticide Redistribution
in the Soil-Water, Soil-Plant System 47
G. G. Zhdamirov, E. E. Popov, and N. F. Lapina,
Institute of Experimental Meteorology
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CONTENTS (continued)
Pesticide Transport and Metabolism in Model Systems 61
D. D. Kaufman, P. C. Kearney, and R. G. Nash,
U. S. Department of Agriculture
Cometabolism of Foreign Compounds , 73
L. A. Golovleva and G. K. Skryabin, Institute
of Biochemistry and Physiology of Microorganisms
On the Estimation of the Anthropogenic Pollution Effect
on the Functional State of the Soil Microflora ........ 86
E. I. Gaponyuk and V. A. Kobzev, Institute of
Experimental Meteorology
Pesticide Transport and Transformation in Water
Co-Chairmen: G. L. Baughman (USA) and M. N. Tarasov (USSR)
Transformation and Transport Processes in Aquatic Systems 98
G. L. Baughman, U. S. Environmental Protection Agency
Estimation of Organochlorine Pesticide Loss in Surface
Runoff Waters 103
Ts. I. Bobovnikova, E. P. Virchenko, G. K. Morozova,
Z. A. Sinitsyna, and Yu. P. Cherkhanov, Institute of
Experimental Meteorology and Institute of Applied
Geophysics
Hexachlorocyclohexane, Metaphos, and Chlorophos Decomposition
in Soil and Their Migration with the Waters of Surface
Runoff 108
M. N. Tarasov, L. G. Korotova, A. S. Demchenko, and
L. V. Brazhnikova, Hydrochemical Institute
Partitioning and Uptake of Pesticides in Biological Systems .... 117
E. E. Kenaga, Dow Chemical U.S.A.
Pesticide Transport and Transformation in Plants
Co-Chairmen: J. J. Menn (USA) and F. P. Waintraub (USSR)
Pesticide Transport and Transformation in Plants 126
D. S. Frear, U. S. Department of Agriculture,
and J. J. Menn, Stauffer Chemical Company
Pathways of Pesticide Dissipation and Decomposition , 140
F. P. Waintraub, G. F. Vylegzhanina, L. P. Dron,
L. S. Kejser, I. p. Nesterova, and F. I. Patrashku,
Ail-Union Institute for Biological Methods of Plant
Protection
VI
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CONTENTS (continued)
Studies of the Behavior of Organophosphorous Insecticides
in Soil and in Soil-Plant System 151
T. M. Petrova, K. V. Novozhilov, T. A. Evstigneyeva,
and F. I. Kopytova, Ail-Union Research Plant Protection
Institute
Pesticide Transport and Transformation in Animals
Co-Chairmen: J. E. Casida (USA) and Y. S. Kagan (USSR)
Metabolism of Pyrethroid Insecticides and Thiocarbamate
Herbicides 163
J. E. Casida, University of California
Basic Trends and Results in the Study of Pesticide Toxicology . . . 171
Y. S. Kagan, USSR Ministry of Public Health
Metabolism and Persistence of Pesticides and Other Xenobiotic
Chemicals in Fish 187
J. J. Lech, Medical College of Wisconsin
Pesticide Movement in the Organism of Farm Animals 190
G. A. Talanov, Research Institute of Veterinary Sanitation
Mathematical Modeling of Pesticide Transport and Transformation
Co-Chairmen: D. W. Duttweiler (USA) and V. M. Voloshchuk (USSR)
Mathematical Modeling of Pesticides in the Environment 194
J. Hill, IV, U. S. Environmental Protection Agency
Quality Analysis and Numerical Experiment in Analyzing the
Effect of the Anthropogenic Pollution of the Biota 198
V. M. Voloshchuk, Institute of Experimental Meteorology
Basic Mathematical Models of Toxicant Transport through
the Soil Profile 201
V. V. Rachinskii, Timiryazev1 Academy of Agricultural
Sciences
Mathematical Modeling and Control as a Radical Way of
Environmental Protection from Pesticide Contamination 210
E. I. Spynu, USSR Ministry of Public Health
Modeling of Pesticide Degradation in Plants and Evaluation
of Their Application Systems 223
L. N. Ivanova, USSR Ministry of Public Health
The Model of the Pesticide Circulation in Fergana Valley 230
V. M. Koropalov and I. M. Nazarov, Institute of Applied
Geophysics
vii
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INTRODUCTION
As part of the 1972 USA-USSR Agreement on Cooperation in the Field of
Environmental Protection, a cooperative program of information exchange on
the environmental transport of agricultural chemicals (pesticides and
fertilizers) began in 1974. Scientists from both countries visited major
research centers to become familiar with the use of pesticides and nutrients
in agriculture and with current concepts and research on environmental
effects of these chemicals.
To focus on a scientific question of particular mutual concern, the
joint project committee sponsored a 7-day symposium on the Environmental
Transport and Transformation of Pesticides, which was hosted by the Soviet
side at Tbilisi on 20-27 October 1976. The symposium was held in conjunc-
tion with the fourth meeting of the USA-USSR Joint Project Committee for
Project 02.03-31, "Forms and Mechanisms by Which Pesticides and Chemicals
are Transported." Eleven US delegates met with 26 Soviet scientists to
discuss six main topics: pesticide transport and transformation in the
atmosphere in soil, in water, in plants, and in animals, and mathematical
modeling techniques for characterizing pesticide migration and transformation
in the environment. Opening remarks by G. G. Svanidze (USSR), D. W.
Duttweiler (USA), and S. G. Malakhov (USSR) emphasized mutual interest
in the symposium topic; the importance of pesticides to agricultural pro-
ductivity; and the value of scientific understanding of the environmental
entry, transport, transformation, ecological effects, and ultimate residual
distribution of pesticides.
This document is a compilation of extended abstracts of papers presented
at the symposium. English translations of the Soviet papers were provided by
the USSR and have not been altered. A brief summary of the symposium appeared
in the Journal of Agricultural and Food Chemistry, Volume 25, Number 5,
pp. 975-978, September/October 1977.
viii
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ATMOSPHERIC TRANSPORT AND TRANSFORMATION OF PESTICIDES
Donald G. Crosby
Department of Environmental Toxicology
University of California, Davis, CA 95616
Pesticides enter the atmosphere on dust particles and by volatilization
from soil and water surfaces, and thus they can travel over great distances.
Cohen and Pinkerton (1) traced the 2000 km movement of a dust cloud from an
agricultural area in Western Texas to Cincinnati, Ohio (Fig. 1), where DDT,
DDE, and 5 other pesticides were detected in it. Rain falling on Ohio also
contained these and other pesticides (Table I).
Many pesticides are quite volatile under certain conditions (2), Al-
though the vapor pressure of DDT is only 7.2 x 10~7 torr (30°C), it evapor-
ates from treated fields at a rate of 5-10 kg/ha/yr Q), depending upon
temperature, moisture, and air movement. However, DDT derivatives such as
o,p'-DDT, DDD, and DDE are more volatile than DDT itself and also are found
after DDT application due to their presence in formulations or to biological
and nonbiological breakdown. Consequently, 66% of the total DDT atmosphere
over a treated field was DDE, and most of the DDT in aerated soil probably
will be volatilized eventually as DDE (Table II). Accurate measurements of
vapor pressures are important in predicting volatilization rates but are
available to only a very limited extent (4).
Mackay and co-workers (5., 6) have calculated the residence time of sever-
al pesticides and other chemicals in water in relation to vapor pressure,
concentration, and other measurable properties (Table III) and have corrected
the values for mass transfer rate. The results indicate much faster transfer
of pesticides from water into the atmosphere than had been generally recog-
nized; for example, the corrected half-life of DDT in water of 1 m depth is
calculated to be 73.9 hrs. Such values are consistent with experimental ob-
servations (3).
Due largely to this volatilization, pesticides have been detected in the
atmosphere over both urban and agricultural areas of the United States.
Stanley and co-workers (T) collected air samples at 9 locations and analyzed
them for 18 compounds (Fig. 2). DDT and related substances always were pre-
sent, BHC isomers tended to occur over urban areas, but campheclor (toxa-
phene) and parathion were found only in rural locations. High levels often
corresponded to periods of low rainfall. Apparently, loss to the atmosphere
either as vapor or particulate matter represents a major aspect of pesticide
transport.
-------
The presence of light, water, reactive surfaces, oxygen, and other oxi-
dants are thought to cause pesticide transformations in the atmosphere. Many
pesticides undergo photochemical decomposition in water or other solvents (o)>
and similar breakdown in the vapor state is not surprising. For example, ir-
radiation of the herbicide trifluralin (I) in vapor form with ultraviolet
light (wavelengths greater than 290 nm) in a glass reactor (9) rapidly pro-
vided the dealkylated and cyclicized products (Fig. 3) reported earlier from
irradiation of solutions (10,LI). DDE vapor reacted similarly to form DDMU,
4,4'-dichlorobenzophenone (VI), a DDE isomer (VII), and chlorinated biphenyls
(12) (Fig. 4).
In order to confirm that the same reactions actually take place in the
atmosphere above treated fields, high-volume air samplers were constructed
either of glass (Fig. 5A) or metal (Fig. 5B). Atmospheric constituents were
caught by glass-fiber filters or by solid, unreactive adsorbents and could be
collected at rates exceeding one m^/min. The air over fields treated with
technical trifluralin — on the soil surface, incorporated into the soil, °r
released directly into the atmosphere as vapor — was shown to contain the
expected photodecomposition products (3.1) (Fig. 6). Note in the figure that
photoproduct formation must have been very rapid initially.
A similar comparison of laboratory and field data for the insecticide
parathion (VIII) (13.,14_) (Fi8- 7) showed that atmospheric oxidants and solid
surfaces were important for photochemical changes; parathion vapor in an
orchard was converted to paraoxon (IX) and then to p-nitrophenol which repre-
sented a stable end-product.
Although only very limited data have appeared on this subject, the
existing evidance shows clearly that many pesticides can be expected to move
readily from soil, water, and other surfaces into the atmosphere and then be
transformed by abiotic chemical reactions into the rather stable and some-
times unexpected products (for example, the chlorinated biphenyls, nitro-
benzimidazoles, and p-nitrophenol mentioned here).
REFERENCES
(1) J.M. Cohen and C. Pinkerton, Widespread translocation of pesticides by
air transport and rain-out, Advances in Chemistry 60, 163 (1966).
(2) W.F. Spencer, W.J. Farmer, and M.M. Cliath, Pesticide volatilization,
Residue Reviews 49, 1 (1973).
(3) W.F. Spencer, Movement of DDT and its derivatives into the atmosphere,
Residue Reviews 59, 91 (1975).
(4) M.M. Cliath and W.F. Spencer, Dissipation of pesticides from soil by
volatilization of degradation products, Environmental Science and
Technology 7, 611 (1973). '
(5) D. Hackay and A.W. Wolkoff, Rate of evaporation of low-solubility con-
taminants from water bodies to atmosphere, Environmental Science and
Technology 7, 611 (1973).
-------
(6) D. Mackay and P.J. Leinonen, Rate of evaporation of low-solubility
contaminants from water bodies to atmosphere, Environmental Science
and Technology 9, 1178 (1975).
(7) C.W. Stanley, J.E. Barney, M.R. Helton, and A.R. Yobs, Measurement of
atmospheric levels of pesticides, Environmental Science and Technology
5, 430 (1971).
(8) D.G. Crosby, The photodecomposition of pesticides in water, Advances
in Chemistry 111, 173 (1972).
(9) D.G. Crosby and K.W. Moilanen, Vapor-phase photodecomposition of aldrin
and dieldrin, Archives of Environmental Contamination and Toxicology
2, 62 (1974).
(10) E. Leitis and D.G. Crosby, Photodecomposition of trifluralin, Journal
of Agricultural and Food Chemistry 22, 842 (1974).
(11) C.J. Soderquist, D.G. Crosby, D.W. Moilanen, J.N. Seiber, and J.E.
Woodrow, Occurrence of trifluralin and its photoproducts in air,
Journal of Agricultural and Food Chemistry 23, 304 (1975).
(12) D.G. Crosby and K.W. Moilanen, Vapor-phase photodecomposition of DDT,
Chemosphere, in press. 1976.
(13) K.W. Moilanen and D.G. Crosby, Pesticide photooxidation in the atmos-
phere, Environmental Quality and Safety 3 (Supp), 308 (1975).
(14) J.E. Woodrow, J.N. Seiber, D.G. Crosby, K.W. Moilanen, and C. Mourer,
Airborne and surface residues of parathion and its conversion pro-
ducts in a treated plum orchard environment. Archives of Environmen-
tal Contamination and Toxicology, accepted for publication in 1977.
-------
Table I. Pesticides Precipitated from the
Atmosphere at Cincinnati, Ohio (!_)
Pesticide Content
Dust (ng/g)
Rain (ng/ml)
DDT
DDE
Chlordane
2,4,5-T
Dieldrin
600
200
500
40
3
0.34 (0.07
0.02 (0.005
•f
+
+
- 1.30)
- 0.02)
+ Signifies detected but not measured
Table II. Volatilization of Pesticides
from DDT-Treated Soil (_3)
In Soil
Chemical
p,P'-DDT
p,p'-DDE
o,p'-DDT
o,p'-DDE
Total
Ratio
to
P.P'-DDT
14.1 1.0
6.2 0.44
2.7 0.19
0.12 0.008
23.1
_In Atmosphere
Ratio
to
ng/m3 p,p'-DDT
104
419
69
26
618
1.0
4.03
0.66
0.25
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Table III. Calculated Evaporation Rates at 25°C (5_)
Biphenyl
Arochlor 1254
DDT
Aldrin
Lindane
Dieldrin
Solubility
(mg/1)
7.48
0.012
0.001
0.2
7.3
0.25
Vapor Press
(Torr)
0.057
7.7 x 10"-
1 x 10~7
6 x 10-6
9 x 10~6
1 x 10~7
Tl/2
(hrs)
7.5
10.3
73.9
185
4,590
12,940
^"'STr^-
7 (*>"«;•
A / 'v SJi?»
tea—-4 I
cC, S , b;
/ •••JIIJ«|«« ^^••CMJtl
/ I
4^
; *B*-to^ ;.i5S!
/ ' ' r—
. , [«..:„„
\ fas.—-L
f I"""
Fig. 1. Pesticide movement on dust from Texas to Ohio, January 1964 (1)
Each curved line indicates 6 hours.
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Rural
Salt Stone- ' Rural
Fresno Lake ville Baltimore Orlando
DDT
DDE
BHC
Camphechlor
Methyl
Parathion
11.2
6.4
4.5
-
-
8.6
-
28.6
-
.
950
47
-
1340
129
19.5
2.4
9.3
-
••
1560
131
-
2520
5.4
Fig. 2. Pesticides in the lower atmosphere (ng/m ) at 5 U.S. Sites
in 1970 (7).
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CF,
02N ^T NO,
N
^ \
H7C3 C3H7
I
,OH
CF,
0,N T N
0,N ^T NO,
X
H7C3 H
n
I
CF
02N
-C3 C2H3
IS
02N ^T NO,
A
H H
XL
0,N N
j
-* 02N
H' 'C2H3
Fig. 3. Photodecomposition pathway of trifluralin (I) in water
or as atmospheric vapor (^£,3.1^).
-------
Cl
H-C-CCL
Cl
Cl
C=CCL
Cl
Cl
C=0
Cl
VI
Cl
Cl
C=CHCI -J-
Cl
VII
Fig. 4. Photodecomposition pathway of DDT and DDE in water or as
atmospheric vapor (12).
FILTER
ADSORBENT
GLASS WOOL
FILTER
ADSOR8ENT
. 100 MESH
WIRE SCREEN
~~FAN a MOTOR
Fig. 5. Diagrams of high-volume air samplers made of glass (A)
or metal (B) (11).
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123456
DAYS AFTER APPLICATION
Fig. 6. Recovery of trifluralin and its major photodecomposition
products from the atmosphere by high-volume air sampling
(11).
-------
VIII
*9c2o-p-'-s
NO
'3
: Vapor
Phoit
ir
NO REACTION
0
OH
NO,
IX
NO.
Fig. 7. Photodecomposition of parathion (VIII) vapor alone
or in the presence of ozone or dust particles (13,14)
10
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ATMOSPHERIC TRANSPORT OF DDT
Borzilov V. A., Malakhov S. G., Osadchii A. I.
Istitute of Experimental Meteorology, Obninsk
Koropalov V. M., Nazarov I. M.
Institute of Applied Geophysics, Moscow
When studying pesticide transport, in particular, DDT transport,
we have to deal with phenomena of various scales. First, it is pes-
ticide dissipation at the instant of application. It corresponds to
the smallest scales, that is, the maximum transport is several kilo-
meters from the application site. Small height of application and
rough dispersity may be responsible for it. Second, it is pesticide
transport on soil particles at wind erosion. Corresponding regional
scales may be as great as hundreds and sometimes thousands kilometers.
An increase in scales is related to the height of dust cloud lifting.
An increase in the scale of transport of the particles not complete-
ly carried with turbulent air pulsations was estimated to be propor-
tional to the cloud height over the underlying surface, and that of
the completely carried particles - proportional to the square of the
height. From this it is not difficult to obtain the above-mentioned
difference in scales. However, these estimates are valid for suffici-
ently large particles which are completely absorbed by the underlying
11
-------
surface. For small particles of about I to 5 microns and pesticide va-
pors which are poorly absorbed by the underlying surface the scales
of transport substantially vary, and conditions are created to draw
pesticides into the global transport. It is the maximum scale of the
process.
Let us briefly dwell on the advances and problems of investigati-
ons in the levels of air pollution and transport processes for each
scale.
I. Near zone. It has received the most study. Dependences have
been found of the concentrations and transport on the size of aero-
sols, method of application, pesticide volatility, meteorological
conditions [_I-5]• Problems occured are the following: variability
of the results under different patterns of the underlying surface
(arable land, grass, forest) and lack of the appropriate regularities.
2. Regional scale. Results of the pesticide concentration measu-
rements over the territory of the United States are given in J6J
which show substantial variability with time (the p,p'-DDT concentra-
tions varied from O.I to 1500 ngr/nr). Higher levels were observed
in the neighbourhood of rural areas at the instances which most of
all favoured evaporation or occurence of the dense dust conditions.
In the latter case the most part of the total amount of DDT found in
the samples was on dust particles. These problems were also discussed
in f 7! where pesticide concentrations in the atmospheric dust in Cin-
cinnati (Ohio) were given. It has been found that the DDT concentra-
tion varied from 5 to 90 ppm. From the total amount of fallen dust it
has been estimated that every month from 45 to 270 g of DDT per km2
12
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fell on the ground. Air pollution with pesticides in the regional
scale was also studied in the Soviet Union using as an example DDT in
Fergana valley and Khorezm oasis in Central Asia. Fergana valley is a
vast inter—mountain hollow with the intensive aeration from December
to April. Over the other periods the aeration conditions substantial-
ly deteriorate. Stagnant phenomena are rather widespread and can lead
to the greater pollution of the whole air volume of the valley with
pesticides. In addition to this, large areas in the valley are affec-
ted by strong wind erosion and there occur dust storms. Results of
the vertical profile measurements of DDT, DDD, and DDE concentrations
over the periods of slight winds (experiments No. I, 2, 3) and strong
dust storm (4-) are given in Table I.
o
In the former case 10 kg of DDT was contained in the air volume in
the valley whereas in the latter one 10* kg was found. Experiment No. 5
was carried out in Khorezm oasis where stagnant phenomena were absent.
In the latter case the amount of pesticides transported from the area
p
on aerosol particles was evaluated at about 10 kg. All the profiles
given in Table I may be described by the following formula
where L/(.f)/is the concentration at the upper boundary of the surface
layer;
is the coefficient of turbulent diffusion;
is the average rate of particle deposition.
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Table I. Pesticide concentrations (DDT, DDE, ODD) on aerosol
particles in Fergana valley (experiments No. 1-4)
and Khorezm oasis (experiment No. 5)
No. of : Height of
experiment : sampling
: (m)
50
100
200
500
400
I 600
800
1000
1200
1800
2500
100
200
500
400
600
3 800
1000
1200
1800
2500
: Concentrations x I0~"10 g/nr
:
:p,p'-DDT:p
120
94
70
85
41
20
17
15
15
5
4
270
190
140
140
68
48
40
28
56
6
,p'-DDD + o,pf-DDT:
24
17
10
15
4
2
4
5
5
I
2
50
10
20
10
8
5
6
5
5
2
p,p'-DDE:]TDDT
144
III
80
96
45
22
21
20
18
4
6
500
200
160
150
76
55
46
55
59
8
14
-------
200
300
5 500
1000
1500
2000
50
100
200
4
400
600
900
50
100
200
5 400
500
1000
66
42
34-
7
12
8
400
420
550
500
250
170
28
45
41
88
24
13
18
13
10
4
4
3
60
70
110
75
4-5
25
^m
10
15
21
10
5
8
4
5
2
3
4
30
25
57
30
24
24
.
10
II
10
8
8
92
59
49
13
19
15
490
515
717
605
319
219
28
65
67
79
42
26
o
Knowing fc/ which in experiments Wo. I, 2, 3, 5 was about 5 m /sec.,
it is not difficult to find that the average rate of DDT deposition is
o
approximately I cm/sec. This gives from 100 to 500 g of DDT per km du-
ring a month that agrees with the data obtained by the American authors*
However, these estimates can not be made until the bulk of pesticide is
absorbed on large aerosol particles. If a pesticide is on the particles
of about I to 5 microns or in vapor phase this impurity behaves as weight-
less, and the mentioned distribution with height should not occur. This
15
-------
means that we can not say definitely about depositions from the measure-
ments of concentration profiles. Their direct measurement is required.
This problem is to be faced when determining depositions at some distance
from the rural region where a rough-dispersive fraction of aerosol par-
ticles is already absent. Pesticide strikes the ground either due washing*'
out or through dry deposition of weightless impurity. There is a progress
in the studies of washing-out after the work [e"] where the coefficients
of washing-out were found for the vapor phase of lindane, dieldrin, and
DDT, It is worse with the dry deposition of small aerosol particles or
with the adsorption of pesticide vapors. Available are only the data L.9J
on the rate of DDT vapor deposition on water and glass surfaces (5 x ^
sec. and 4 x ICT^cm/sec., respectively). Under actual conditions these dat*
for aerosol and vapor components have not been obtained. Not numerous
f~IO, IIJ showed that the rate of deposition dL depends on the pattern of
underlying surface, the value of particle cohesion with the surface, etc.
However, it has not been possible to obtain any regularities other than the
dependence on the dynamic wind velocity
The flow on the underlying surface (JL= 0) turned out to be related to OL
in the following way:
- air*c (5)
%^o *-o
However, all information on the surface properties is given as before
by a single parameter Q. We made an attempt to find an explicit de-
pendence of eL. on the underlying surface parameters being measured
16
-------
[l2j. For this purpose the surface was represented by the layer of
vegetation with the height <5C and specific surface
-------
tions. The major problem here is selection of the scales of averaging.
Both diffusion coefficients and the rates and directions of average
transport will change depending on this. We performed calculations
of the amount of DDT depositions on the ground from Khorezm oasis
which agree qualitatively wiih the measured ones.
2. Global scale. Analysis of the data on the global levels of at-
mospheric pollution with persistent pesticides shows that these le-
vels are very variable and substantially depend on synoptic conditi-
ons and air currents in the lower troposphere. According to the data
obtained by the American authors which relate mainly to the Atlantic
ocean, the levels of DDT concentrations vary from 20 x 10 g/nr j
to 200 x 10 g/nr l4« These levels were found on aerosol compo-
nent. As regards the pesticide content in vapor phase, there is no
agreement on this problem for lack of reliable techniques of separa-
tion of aerosol and vapor components.
It was shown in work JI5J that the toxaphene concentrations over
the Atlantic ocean in the area between the Bermudas and the U.S. sea
coast are due to the transport of this pesticide from the southern
states of the United States. Therefore the maximum concentrations were
observed in these areas when there occured the air masses of appropri-
ate origin. Prom this it follows that it is essential to know about
the air mass history when studying fluctuations of the global levels
of atmospheric pollution. We should like to place emphasis on the fact
that neglect of these factors can lead to wrong interpretation of the
JtJL ^2^> r 1
experimental dataT^Trospero andTSCba [I4J report on several cases of
high and low values of DDT concentrations nearby Barbados and compare
these concentrations of pesticide and those of dust. Thus, on July 16,
18
-------
1970 high DDT concentrations and Low those of dust were observed, where-
as on July 18, 1970, on the contrary, DDT concentrations were low and
those of dust were high. For reasons given it was concluded in this
work that the Sahara dust had a washing effect on pesticides over the
aquatoria of the Atlantic ocean. However, a detailed analysis of meteo~
rological situations showed that high pesticide concentration levels
occured at the instants of air mass advection from the territory of
the American continent. Low concentrations were related to the air
mass transport with trade winds from the Sahara, It should be noted
that the values of the background level of pesticide concentrations
serve as the basis for the development of corresponding balance mo-
dels and pesticide global circulation models. Taking into considera-
tion scant statistics of the background measurements and their high
variability, we should impose heavy demands on their interpretation.
19
-------
References
I. P. D. Gerhadt, J. M. Witt. Proc. 12th Internat. Congr. Entomol.,
London, 1964.
2. G. C. Decker et al. Journ. Econ. Entomol., 42, 1950-
2. Sh. T. Atabaev. Pesticides and hygiene of the environment under
hot climate conditions. Izd-vo "Meditsina" Uzbek SSR, Tashkent,
1972.
4. V. A. Gofmeckler, L. A. Safonova. J. "Gigiena i sanitariya" No. 9,
1975.
5. K. P. Makhon'ko. Proceedings of Experimental Meteorology Institute,
1 (42), 1974.
6. C. W. Stanley et al. Env. Sci. Tech., 1971, vol. 5, No. 5.
7. J. M. Cohen, C. Pinkerton. Adv. chem. ser., 60, 1966.
8. D. H. P. Atkins, A. E. J. Eggleton. Proc. Symp. Nuclear Techn.
Environ. Pollution I. A. E. A. Vienna, 1971.
9. G. A. Wheatley. Pesticides in atmosphere. Environmental pollution
by pest (ed. by C. A. Edwards), 1973.
10. A. C. Chamberlain. Proc. Roy. Soc., Ser. A, 296, V. 1444, 1967.
II. N. L. Byzova, K. P. Makhon'ko. Izvest. Akad. Nauk S. S. S. R.,
Physics of Atmosphere and Ocean, 2, No. 7» 1965.
12. V. A, Borzilov, N. B. Senilov. Proceedings of Experimental Meteo-
rology Institute, 2 (76), 1976.
13. R. W. Riserbrough et al. Science, vol. I59» 1968.
14. J. M. Prospero, D. B. Seba. Atm. Env., Vol. 6, 1972.
15. T. F. Bidleman, C. E. Olney. Nature, Vol. 257, No. 5526, 1975.
20
-------
DISPAR1URE AND SOME JUVENILE HORMONE ANALOGUE
PERSISTENCE IN THE ENVIRONMENT
Weintraub P.P., Vylegzhanina G.F., Chernichuk L.L.,
Konjukhova I.A.
All-Union Institute for Biological Methods
of Plant Protection, Kishinev
Necessity of the working out of new principles of plant
protection from harmful insects, that provide purity of the envi-
ronment, has led to the investigations on pesticides of the third
generation - attractants and juvenile hormone analogues. A rather
voluminous material on their field and production tests has been
accumulated. Much less is known on their stability and persistence
in the environment though these problems have to be solved as well.
Attractant effectiveness depends on a number of factors
among which the presence of pheromone vapours in the air seems
to be the main one. Their release rate in-foSYatmosphere is almost
not studied. Practically there are data on vapour pressure and
some compounds volatility. There are no such data on disparlure-
cis-7,8 epoxymethyloctadecane- gypsy moth attractant as well.
To get these data we used the classical method such as pure
dry air blowing over disparlure surface. The air was dried and
absorbed by passing through calcium chloride and activated carbon
21
-------
AG-3. Vapour catching took place in two successively connected
traps filled with hexane and plunged into the cooling mixture.
The vessel with disparlure was put into the thermostate. Diepar-
lure was determined with the help of gaschromatography. The re-
sults are given in Table I. Pressure curve of disparlure vapour
and volatility curve calculated according to the least square
method are of linear character and correspond to the equations
log P * - 5,2757 + 0,02216
log P m - 1,4248 + 0,02973
These data gave possibility to approach a question of dis-
parlure determination in air. At present, works on disparlure
identification in the air, its environmental metabolism are carried
Table I.
Vapour pressure and volatility of disparlure at
different temperatures
Temperature,
°C
15
20
25
30
35
40
45
50
: Vapour pressure, mm Hg :
column x I0~5
1,03
1,38
1,81
2,43
3,18
4,12
5,20
6,76
Volatility,
jie/i
0,09
0,13
0,20
0,29
0,42
0,60
0,86
1,21
22
-------
out in the laboratory* The results will be published. At controlled
temperature (20-35°C) and relative air humidity (40-50$ and 80-
I00#) conditions volatilization rate of disparlure applied on
foil plates was investigated* Disparlure residue was determined
with the help of gaschromatograpny. Obtained data, being statis-
tically processed, showed significant influence of temperature
and air movement on this process (Pig,I), The importance of
humidity influence on the process of disparlure release wasn't
proved.
left
50
30
10 '
20° C
8 h
Figure I. Temperature influence on loss of
disparlure from the foil plates.
23
-------
Obtained data on the release of disparlure applied on filter
paper in laboratory and field tests correlate well (Pig.2).
The results show that disparlure evaporates quickly and it
gives possibility to think that it will be absorbed by soil and
water.
lost
250
200
150
100 '
50
10
20
30
40
50
60 days
Pig.2. Disparlure loss from filter paper in
the field (a) and laboratory (b) con-
ditions.
Air temperature in the field is 20 -25°c,
in thermostate - 25 C; wind speed in the
field is 1,0-2,1 m/sec., in thermo-
state - 1,5 m/sec.
24
-------
Juvenile hormone analogues as plant protection means from
noxious insects are used the same way as classical pesticides.
Applied compounds can volatilize , influenced "by sun, tempera-
ture, oxygen, air humidity, wind and other factors, that in the
end can lead to the possibility of the environmental pollution.
Investigations that had been carried out on some juvenile hormone
analogues: altosar (ethyl- 3,7»H-trimethyl-dodeca-2,4-cLienoate},
altosid (isopropyl-II-methoxy-3i7,II-trimethyl-2,4-dodecadienoate)
and bromphenoxygeraniol /I-(4-B-phenoxy)-3»7-dimethyl-2,6-octa-
diene/ - allowed to determine interrelation between vapour pressure
and altosar, altosid and bromphenoxygeraniol volatility and their
persistence time on treated surface (Table 2), Rather high vapour
pressure and altosar and altosid volatility lead to a high rate
of technical product loss in the process of air blowing. At the
same time bromphenoxygeraniol is not enough volatile and it may
be expected that it will persist longer in field conditions.
Light can also cause degradation of these compounds. In our expe-
riments short time ultra-violet irradiation of bromphenoxygeraniol
(about I hour) leads to its practically complete degradation. Po-
lar zone formation was identified by thinlayer chromatography.
Sunlight irradiation of bromphenoxygeraniol gives analogous
results but the process is retarded. In 18 hours 20,9# of the
compound in comparison with the initial amount was found on treated
surface. The study of temperature influence on bromphenoxygeraniol
showed that in closed volume it was stable in the range 30-80°C
(Pig.3). At temperatures higher than 80°C a significant decrease in
25
-------
Table 2
Vapour pressure, volatility and persistence of
some juvenile hormone analogues on potatoes
Compound
P mm
:Vo- : Persistence,
la- leaves
Hg column ?^~ -. .. ,, N
: ° :li- :Ini- : time (days)
ty, tial
mg/
m-^
:amo- : I : 2
unt
: 4
Altozar
Altosid
Bromphenoxy-
geraniol
20 6,04.IO~4 8,87 0,26 0,094 0,016 tra- not
ces de-
tec-
ted
20 5.25.IO"3 91,75 0,62 0,430 0,048 0,024
0,005
not deter-
mined
59,0 7,45
4,08 not
de-
ter-
mi—
ned
the compound content was noticed. In field conditions wind is
another factor that decrease bromphenoxygeraniol content. As a
result of the influence of all studied factors in laboratory and
field tests on potato plants treated with emulsifiable concentrates
of altosar (53# a.i. ), altosid (65,5% a.i.) and bromphenoxygera-
niol (100$) at rates 1,5 and 3 kg per hectare, persistence time of
juvenile hormone analogues on leaves was not more than 3-5 days
(Table 3). When rainfall occurs persistence time of altosar and
altosid was sharply reduced. Thus under the influence of heavy
26
-------
a
g
•H
+»
2
100
80
S 60
4*
§
(0
4>
CD
0>
J3
4*
40
20
Figure 3» Bromphenoacygeraniol lose from the
glass surface as influenced by temperature
and wind*
showers in 24 hours only altozar traces were found on potato leaves,
Altosid persisted a little bit longer. In 24 hours about 50^ of
the compound was found, in 48 hours - 6,5$ as compared with the
initial amount.
The study of persistence time of juvenile hormone analogues
in soil is also of significant interest. In the laboratory test
the influence of these factors on altosid persistence time in the
soil was studied under controlled temperature and soil humidity
conditions. Investigations showed (Pig.4) that altosid degradates
27
-------
Table 3
Persistence of altozar and altosid on potatoes
leaves following treatment
Time , days
0
I
2
3
8
! Altozar,
1,5 kg/ha
0,340
0,170
0,004
traces
not de-
termined
mg/g
: 3,0 kg/ha
0,650
0,250
0,004
traces
not
determined
' Altosid,
- mg/g
3,0 kg/ha
0,500
0,380
0,240
-
0,060
quickly in the soil. Its losses were in average 98,6$ at 20°C in
14 days after treatment. The increase of temperature to 30°C
reduces persistence time to 10 days, the increase to 40°C - to
4-6 days. The increase of relative soil humidity from 1856 to
accelerates altosid degradation in the soil.
28
-------
\% of loss
100
x -t-20°C
A -t«OO°C
o -t»40°C
-humidity 17,
_._ -humidity 22-
10
12 14 days
Figure 4. The dependence of the altosid persistence
in the soil on temperature and humidity.
29
-------
PREDICTING AND SIMULATING PESTICIDE TRANSPORT FROM AGRICULTURAL LAND:
MATHEMATICAL MODEL DEVELOPMENT AND TESTING
George W. Bailey*
H. P. Nicholson*
United States Environmental Protection Agency
Pesticide transformation (7, 11, 14, 15, 16, 17, 19) and transport
processes (3, 4, 9, 12, 13, 18, 20, 21, 22, 24, 25) in soils have been defined
and reviewed extensively. These processes and their interrelationships within
the soil and to other compartments in the environment are schematically
depicted in Figure 1. The transport of pesticides from agricultural lands and
other compartments of the environment has generated public apprehension
concerning the fate and effects of these compounds. Legislative mandates
require guidelines to be developed covering pesticide use in order to prevent
or minimize water pollution resulting from pesticide transport from
agricultural land (26). Mathematical models and computer simulation
techniques rather than the trial and error approach are the most viable
alternatives to arrive at these guidelines (2).
Computer simulation models of the dynamic multiple rainfall-event type
are being developed and refined to describe and predict quantitatively
transport of pesticides from soil as a function of agricultural management
practices, watershed characteristics, climatic factors, and properties of
soils and pesticides. These models must account for the behavior of
pesticides in soils during each rainfall event, and between rainfall events
(2). Processes occurring during a rainfall event and accounted for by the
model are downward movement and net pesticide transfer from the soil surface
into the runoff film, both in solution and adsorbed on eroded soil. Processes
affecting pesticide concentration and phase redistribution between rainfall
events include evaporation, adsorption, desorption, net pesticide movement
under conditions of unsaturated flow, and chemical, microbial, and
photochemical transformation processes, volatilization, and organism uptake.
Models capable of predicting at two areal scales are required: (a) at
the farm-unit size watershed scale (hectares) to assess the effectiveness of
agricultural practices and alternative control measures to control water
pollution and (b) at a basin-scale (square kilometers) to predict the
contribution of multiple agricultural land use on water quality.
*Environmental Research Laboratory, United States Environmental Protection
Agency, College Station Road, Athens Georgia 30601.
30
-------
Steps involved in model development, testing and verification will be
discussed in detail and include (a) system definition (Figure 2) and
formulation of a conceptual model (2); (b) assemblage of a multidisciplinary,
multi-institutional research team and the integration of team efforts; (c)
selection, design and instrumentation of 1-3 ha farm-unit size watersheds and
36-48 km size watersheds; (d) design and installation of highly
instrumented, small experimental plots (6 X 9 m) to study pesticide
degradation kinetics as a function of soil properties and meteorological
parameters (23); (e) development of data handling and computerized data
processing programs; (f) selection of experimental pesticides to "track" four
major modes of transport; (g) development of rapid, sensitive, integrated
analytical methods; (h) selection of agricultural management practices and
compatible cropping systems; (i) continuous monitoring of meteorological
parameters, soil, water and pesticide loss during runoff events and the
determination of pesticide spatial and tempera! distribution vertically and
horizontally over the watersheds for a period of three to four years; (j)
development of algorithms for adsorption/desorption, pesticide degradation,
volatilization, snow accumulation and snowmelt and pesticide mass transfer
coefficients from soil to runoff waters; (k) interfacing these algorithms to
the basic hydrologic and soil loss routines; (1) programming, calibration, and
testing of the overall model; (m) sensitivity analysis of selected model
parameters; (n) specific parameter generation, e.g., adsorption/desorption
isotherms for a variety of pesticides and edaphic conditions; and (o)
verification of the overall model at both areal scales in different geographic
regions using either "new" or split data sets.
Four basic pesticide runoff models have been developed and tested to
varying degrees (1, 5, 6, 10) and one refined and updated to include snow
accumulation, snowmelt runoff, and nutrient transformation and transport (8).
The structure and operation (Figure 3) flow chart (Figure 4), input/
output requirements, sample results, simulative capability and observed
problems or deficiencies for a farm-unit size watershed scale pesticide
transport model (8) using the lumped parameters/statistical approach will be
discussed.
Approaches and problems for model scale-up and interfacing to basin-scale
water quality model will be treated.
REFERENCES
1. Adams, R. T. and F. M. Kurisu. 1976. Simulation of Pesticide Movement
on Small Agricultural Watersheds. U. S. Environmental Protection Agency.
In press.
2. Bailey, G. W., R. R. Swank, Jr., and H. P. Nicholson. 1974. Predicting
Pesticide Runoff from Agricultural Land: A Conceptual Model. J.
Environ. Qual. 3:95-102.
3. Bailey, G. W. and J. L. White. 1964. Review of Adsorption and Desorp-
tion of Organic Pesticides by Soil Colloids, with Implications Concerning
Pesticidal Bioactivity. J. Agr. Food Chem. 12:324-332.
31
-------
4. Bailey, G. W. and J. L. White. 1970. Factors Influencing the
Adsorption, Desorption, and Movement of Pesticides in Soil. Residue Rev.
32:29-92.
5. Bruce, R. R., L. A. Harper, R. A. Leonard, W. M. Snyder, and A. W.
Thomas. 1975. A Model for Runoff of Pesticides from Small Upland
Watersheds. J. Environ. Qual. 4:541-548.
6. Crawford, N. H. and A. S. Donigian, Jr. 1973. Pesticide Transport and
Runoff Model for Agricultural Lands. EPA-600/2-74-013, U. S.
Environmental Protection Agency, Athens, Georgia.
7. Crosby, D. G. 1970. The Non-Biological Degradation of Pesticides in
Soil. In: Pesticides in the Soil: Ecology, Degradation and Movement.
International Symposium on Pesticides in the Soil. Michigan State
University, p. 86.
8. Donigian, A. S., Jr. and N. H. Crawford. 1976. Modeling Pesticides and
Nutrients on Agricultural Land. EPA-600/2-76-043, U. S. Environmental
Protection Agency, Athens, Georgia. 318 pp.
9. Freed, V. H. and R. Hague. 1973. Adsorption, Movement and Distribution
of Pesticides in Soil. In: W. Van Valkenburg (ed.), Pesticide
Formulations, Marcel Dekker, New York. pp. 441-451.
10. Frere, M. H., C. A. Onstad, and H. N. Holtan. 1975. ACTMO: An Agri-
cultural Chemical Transport Model. ARS-H-3, U. S. Department of
Agriculture, Agricultural Research Service.
11. Goring, C. A. I., D. A. Laskowski, J. W. Hamaker, and R. W. Meikle.
1975. Principles of Pesticide Degradation in Soil. In: R. Hague and V.
H. Freed (eds.), Environmental Dynamics of Pesticides, Plenum Press, New
York. pp. 135-172.
12. Green, R. E. 1974. Pesticide Clay-Water Interactions. In: W. D.
Guenzi (ed.), Pesticides in Soil and Water, American Society of Agronomy,
Madison, Wisconsin, pp. 3-37.
13. Guenzi, W. D. and W. E. Beard. 1974. Volitilization of Pesticides. In:
W. D. Guenzi (ed.), Pesticides in Soil and Water, American Society of
Agronomy, Madison, Wisconsin, pp. 107-122.
14. Jordan, L. S., W. J. Farmer, J. R. Goodin, and B. E. Day. 1970. Non-
biological Detoxification of s-triazine Herbicides. Residue Rev. 32:29-
92.
15. Kearney, P. C. and D. D. Kaufman (eds.). 1969. Degradation of
Herbicides. Marcel Dekker, New York. 394 pp.
16. Kearney, P. C. and J. R. Plimmer. 1970. Relation of Structure to
Pesticide Decomposition. In: Pesticide in the Soil: Ecology,
32
-------
Degradation and Movement. International Symposium on Pesticides in
Soils. Michigan State University, pp. 65-71.
17. Kahn, M. A. Q., M. L. Gassman, and S. H. Ashrufe. 1975. Detoxification
of Pesticides by Biota. In: R. Hague and V. H. Freed (eds.), Environ-
mental Dynamics of Pesticides, Plenum Press, New York. pp. 289-329.
18. Leonard, R. A., G. W. Bailey, and R. R. Swank, Jr. 1976. Transport,
Detoxification, Fate and Effects of Pesticides in Soil, Water, and
Aquatic Environments. Proceedings of Land Disposal of Waste Symposium,
Soil Conservation Society of America, Des Moines, Iowa, March 15-18,
1976. In press.
19. Moilanen, K. W., D. G. Crosby, C. J. Soderquist, and A. W. Wong. 1975.
Dynamic Aspects of Pesticide Photodecomposition. In: R. Hague and V. H.
Freed (eds.), Environmental Dynamics of Pesticides, Plenum Press, New
York. pp. 45-59.
20. Nicholson, H. P. 1975. Agricultural Chemicals and Water Quality. In:
M. C. Blount (ed.)> Water Resources Utilization and Conservation in the
Environment, Taylor County Printing Company, Reynolds, Georgia, pp. 214-
227.
21. Nicholson, H. P., A. R. Grzenda, G. J. Lauer, W. S. Cox, and J. I.
Teasley. 1964. Water Pollution by Insecticides in an Agricultural River
Basin. Part I. Occurrence of Insecticides in River and Treated
Municipal Water. Limnol. Ocean. 9:310-317.
22. Pionke, H. B, and G, Chesters. 1973. Pesticide-Sediment-Water Inter-
actions. J. Environ. Qual. 2:29-45.
23. Smith, C. N., R. L. Estes, T. W. Culbertson, D. M. Cline, and G. W.
Bailey. 1976. Design and Use of Small Runoff Plots and a Continuous
Environmental Monitoring System to Aid in Modeling Pesticide Attenuation
Processes. To be submitted to J. Environ. Qual.
24. Spencer, W. F. and M. M. Cliath. 1976. The Solid-Air Interface: Trans-
fer of Organic Pollutants Between the Solid and Air Phases. In: I. H.
Seffet (ed.), Adv. in Environmental Science and Technology, John Wiley,
New York. In press.
25. Spencer, W. F. and M. M. Cliath. 1976. Vaporization of Chemicals. In:
R. Hague and V. H. Freed (eds.), Environmental Dynamics of Pesticides,
Plenum Press, New York. pp. 61-78.
26. U. S. Environmental Protection Agency. 1972. Federal Water Pollution
Control Act Amendments, PL 92-500, October 18, 1972.
33
-------
TRANSPORT AND FATE OF PESTICIDES IN THE ENVIRONMENT
SURFACE APPLICATION
SURFACE APPLICATION
AND SOIL INCORPATION
DEGRADATION
VOLATILIZATION
WIND |
EROSION
VOLATILIZATION
I
INTERCEPTION
MAN
_.|N LAND DISPOSAL
SORPTION I SPIL'LAGE
otmrTION | ACCIDENTS
AND DEPOSITION INDUSTRY
SEWAGE
MAN
SPILLAGE
ACCIDENT
INDUSTRY
SEWAGE
1 PHOTOCHEMICAL
AGGRADATION
DECAY EXUDATI
ABSORPTION-^ATiR"
ADSORPTiON ESORPTN *
SUBSURFACE WATER
CHEMICAL AND BIOLOGICAL
DEGRADATION
HARVESTED CROP
i CHEMICAL AND BIOLOGICAL
DEGRADATION
Figure 1. Transport and fate of pesticides in the environment (18).
-------
U)
Ul
[^VOLATILIZATION)
OROANISM UPTAKE)
PESTICIDE CONCENTRATION
AVAILABLE FOR
AND TRANSPORT
Figure 2.
' MOVING "\
'•^DISSOLUTION/
DESORPTION FROM
v SOIL PARTICLES /
\DIS30LUT ION/
DIFFUSION
\HtTERCH AN«E/
LEGEND
DURING RAINFALL EVENT
BETWEEN RAINFALL EVENT
PRIOR TO FIRST RAINFALL EVENT
PROCESS
D FACTOR
Processes and factors which determine the concentration of pesticide available for
runoff from agricultural land. Climatic factors lying outside of the dashed lines
are exogenous with respect to the soil-pesticide system (2).
-------
INPUT
OUTPUT
U)
MAIN
EXECUTIVE
PROGRAM
-^CHECKR CHECK INPUT SEQUENCE
-*-NUTRIO READ NUTRIENT INPUT
OUTMON, OUTYR OUTPUT SUMMARIES
LANDS
HYDROLOGY
AND SNOW
SEDT
SEDIMENT
PRODUCTION
PEST
YES
NUTRNT
NUTRIENT TRANSFORMATION
AND REMOVAL
YES
NO
NUTR
ADSRB
PESTICIDE ADSORPTION
AND REMOVAL
DEGRAD
PESTICIDE
DEGRADATION
Figure 3. ARM model structure and operation (8).
-------
TOTAL U
AND DEI
/
\ APPLICATION /
PTAKE
iRADATION ,
APPLICATION
p MODE
SOIL INCORPORATED p/N ON S
IIIPFIPF IPPI IFn '
tiPTivr tun _. riiDFIPF P/N 5URFACF P/N PESTICIDl
-1 UrlNHL AWU ^ 1 iUKrdUt r/n M w aunrnfci .•.'•; r
DEGRADATION STORAGE INTERACTIONS
INFILTRATION
i
...... wr -un ' *• iippcp jnuf p/y UPPFI 70NF P/M ^/" '" '
- UPTAKE AND UPPtK ZONt r7N < — ». u.vJ,vLrl??i7iuc
DEGRADATION « STORAGE INTERACTIONS
PERCOLATION
t
UPUKE AND „ ILOWER ZONE P/N ^_^ LOW
- DEGRADATION * 1 SIORAGE INI
KEY
( INPUT )
FUNCTION
| STORAGE ]
P- PESTICIDE
.EDIMENT M-MUTRIEMT r
PARTICLES ^
VERLAND FLOW r
NTERFLOW ^
ER ZONE P/N
ERACTIONS
I
LOSSES TO GROUNDWATER
TO STREAM
Figure 4. Pesticide and nutrient movement in the ARM model (8).
-------
GENERAL LAWS OF THE MIGRATION OP PESTICIDE
RESIDUES IS THE DELTA LANDSCAPE UNDER
IRRIGATION
M.S.Sokolov
Institute of Agroehemistry an'* Soil Science of the USSR
Academy of Sciences
Puschino
Migration and transport of both, the atoms of the elements
and the natural compounds are, in the opinion of T.I.Vernadski
(1927)* one of the geochemical laws of biosphere* This universal-
ly observed process has lately been involving various zenobiotics
introduced artificially into the landscape, e.g. pesticides, the
products of their transformation and destruction* V.A.Kovda (1373)
ouggests that the process of migration determines diverse aftereff.
ects caused by biocidea and other xenobiotics (landscape-regional,
regional-basin and global ones) in the biosphere.
Migration can be characterized as a complex of processes of
redistribution of xenobiotics (and the products of their trans-
formation) in space and in time (A.E.Foreman, 1933; V.L.Anok>*in,
1974)* In the process of redistribution a pesticide can be trans-
formed into various products* The leftovers of the parent com-
pound together with the products of its transformation are de-
fined aa pesticide ^/esidues.
Zenobiotics are mainly transported in aquatic medium, in
atmosphere and through organism migration. In the aquatic medium
xenobiotics are transported with the surface and subsurface
runoff. In the first case, the compounds are transported in the
form of a liquid runoff (true solutions of electrolytes, compounds
with neutral molecules, and colloidal solutions), and in the form
38
-------
of a solid runoff (suspensions, aorbed substances with precolloidal
particles or organo-mineral colloids). The subsurface transport
of xenobiotics is carried out principally in the form of a liquid
runoff (V,A*Kovda, 1974; M.A.Glazovskaya, 1972)* Under the condi-
tions of the delta irrigate* landscapes the water runoff is
controlled, the surface runoff to a greater, and the subsurface
runoff to a lesser degree. The transport of large water masses
by these pathways is, consequently, of a clearly defined
seasonal character.
Transport of toxicants by the subsurface runoff is usually
underestimated on the account that the rates of ground water flows
ar« incomparable to the water velocity in rivers or canals of the
open irrigation system. That is really so, and under the condition^
of the time-limited parametres the intrasoil transport may be neg-
lected, especially, in case of a point pollution source. Under the
conditions of large rice irrigation systems the coefficients of
land-use reach maximum values (over 50$) as well as tne crop rota-
tion saturation with rice (60-70#). And the rice is being treated
with the same preparations for laany years. That is why the subsur-
face transport of pesticide residues here should always be taken
into consideration. Evidently, the larger is the territory treated
with pesticides,the greater its evaporation and filtration losses,
the heavier would be the share of pesticide residues trasported
with the subsurface runoff. Thus, in the USSR as a whole the sub-
surface runoff calculated per water constituent amounts to only
25$, while the share of the total ion subsurface runoff is over
5G$. Even more dramatic figures have been found for the internal
drainage basin of the Aral sea which has 83% migrants per subsur-
face ion runoff ("Migration of Chemical Elements in the Ground
Water of the USSR. Laws and Quantitative Estimation", Moscow, 1974)
The runoff driving force is determined with the help of the
gradient of water level in a water source (a river, an irrigation
canal, a water reservoir) and in a water-receiving reservoir (a sea
a lake, a river, a trunk canal). While approaching the water-receiv-
ing reservoir the absolute valueu of water levels in the open sys-
39
-------
tern diminish reaching zero and negative values at some areas.Ope-
ration of the hydrotechnical constructions (pump house stations),
however, maintains the surface runoff at the required level. The
transport of substances by the subsurface runoff i_ consequently
slowed down. A similar picture is characteristic of the period of
intensive use of irrigation systems (the growing season). After
harvest only a small part of the surface runoff (unlike the subsur-
iace runoff) ie retained in some elements of the natural hydrogra-
phic system. The action cf the surface and subsurface runoff results
in the creation of a ~one of secondary accumulation (redeposition)
of pesticide residues in the natural conditions (V.A.Kovda, 1973;
B.P.Strekozov et al., 1977; M.S.Sokolov, 1977).
The mechanisms of toxicant transport with surface and subsur-
face runoff are greatly influenced by nature and by peculiarities
of ground composition. V.L.Anokhin (1974) distinguishes the follow-
ing four casoe: free transport of the migrant without delay in the
filter layer; mechanical filtration of the suspended coarse-dis-
persed particles of the migrant-carrier (colmatage); coagulation
and sedimentation of the colloidal-dispersed particles on the
contact border of the liquid and solid phases; dissolving of the
component on the solid phase surface (leaching) or its reverse
process, chemisorption. T.B.Zaitsev (1975) distinguishes several
principal types of ground water occurrence to be considered in
rice irrigation with flooding, and two basically different regimes
of ground water under the flooded rice field: with Joining irriga-
tion (surface) and ground waters and a non-joining regime during
the whole growing season.
Many scientists investigate the peculiarities of vertical
migration of pesticides and other zenobiotics in the ground with
undisturbed structure using the techniques borrowed from the soil
science, «.g. the method of the so-called "flooded Biter" , or
"flooded sashes". We also employed this method and got some infor-
mation on the peculiarities of movement of the main herbicides
applied in rice breeding and certain products of their transforma-
tion, over the water-saturated profile of the meadow-chernozbm-
40
-------
like aoil (M.S.Sokolov et al., 1974). On the basis of these data
and experiments on sorption under the static conditions we arrived
at the conclusion that any chance of the herbicide residues enter-
ing the ground water is practicably excluded. However, the experi-
ments on water analyzing in sash drainage canals (M.S.Sokolov et al
1974) and the experiments with observation wells drilled in the ric
field and nearby, at different depths (from 0.5 to 2.5 m) as well
as the use of special appliances for sampling interstitial soluti-
ons of the upper undisturbed layer of the ground (at 0,2-0.5 m
depth) proved the contrary (Seveorov et al*, 1975; M.S.Sokolov et
al.,1977). Comparatively small quantttLes (up to \% of the introduc-
.-d dose, in average) of the residues of propanil and colinate
migrate with the irrigation water along the pores, cracks or ca-
vities into the lower-lying soil horizons* This fact emphasizes
the necessity of taking into account both, the microstrueture and
the macrocomposition of the soil and subsoil while characterizing
the soil profile,Transport of water and water-contained substances
downward (along the soil profile) is achieved due to the gravity
(percolation, filtration) and diffusion forces. However, the con-
tribution of the latter into the migration process is negligible.
The rate of the vertical percolation is determined by the
value of the porous spacing in the ground, peculiarities of its
structure, s well as by the level and type of ground water occurr-
ence (V.B.Za-Usev, 1975; I»Q.Aliev, 1976). In general, the dis-
tribution of the migrant along the soil profile and over various
ground-water horizons is described with the help of the exponenti-
al law. The distribution zone of the migrant usually lags behind
the water movement even under the leaching irrigation regime due
to the non-saturation of the soil absorbing complex in the thick-
ness of porous spacing.
The irrigation system and various types of drainage intensify
the intrasoil (spatial and vertical) transport of pesticide resi-
dues thanks to the lowering of the ground water level. Observation
wells drilled perpendicular to the trunk canal helped to examine
the dynamics of the herbicide residues content in the ground water.
41
-------
It appeared that in the close vicinity of a canal (a drain) the
substance concentrations in the ground flovr and in the canal water
are close (M.S.Sokolov et al«, 1975; A.P.Chubenko, B.P.Strekozov,
1976; A.P.Chubenko, 1975; 1976). That can be observed in cases
when +he flows of ground water and canal water are comparable. In
case of the ground water flow polluted with herbicide residues,
moving along ths natural slope of the locality towards water in-
takes, the content of toxicants in the subsurface runoff is not
directly connected with their concentration in the open collector
system. The fact is explained not only by the difference in the
water flows but also byihe different buffer action and self-purifi-
cation capacity of th^ landscape. The buffer action of these two
processes is stipulated by abiotic and biotic factors (A.H.TJurju-
kanov, 1964; A.I.Pertlman, 1973). Their action is very often mani-
fested In the natural and irrigation water, in soil and subsoil,
in the bottom deposits and biota, simultaneously and in correla-
tion. Among the abiotic factors the main part in the buffer actioz
Js played by sorption, among the biotic factors, by metabolic
processes. The buffer action regulated by the abiotic factors
aharplj decreases with the reduction of water exchange, in the
absence of insolation and during salinization. With the lowering
into the soil and subsoil the role of the bioxic factors in the
buffer action decreases too. Evidently, the conditions of self-
purification of the ground water unlike those of the surface water
are extremely unfavourable on the account of constant temperature,
increased salinity, impoverished microflora, absence of substrates
for co-oxidation, extreme values of pH, absence of conditions
necessary for photochemical transformations and, lastly, more pro-
nounced anaerobic conditions. All this promotes a prolonged reten-
tion of toxicants in the ground flow. Unfortunately, these speci-
fic conditions are never considered while staging modelling expe-
riments on the subsoil*
The transport of pesticide residues with the surface solid
runoff and the fate of the migrant "buried1* with the benthal sludge
42
-------
and eubcolloidal particles of the shelf and estuarine zones of
water intakes of the returned irrigation water are not sufficiently
studied either* It turned out that propanil and 3,4-DCA 'the prin-
cipal product of herbicide transformation) are effectively aorbed
by the sludge and clay fractions of the meadow-chernosern-like
soil (M.S.Sokolov et al*j 1374)* Th« toxicants in the sorbed state
are transported over large distances along the units of the irrl?i~
ed system where the greater part of the accumulation and redepop-
tion of the suspended matter occurs (B.P.Strekozov et el., 1975).
However, the heaviest fraction settles down in the so-called cla-
rification area of the water intakes, in the absence of water
current* is the absolute content of propanil residues in the benthit
deposits turns to be small (0-0.7 mg/kg), their concentration in
the firth w«ter is much lower than the maximum permissible one
(B.P.Strekozov et al., 1977; M.S.Sokolov etal., 1977)* But due to
the unfavourable conditions of decomposition and desorption there
should go on a slow but constant process of toxicant cumulation*
Therefore, under the circumstances, it is necessary to anticipate
the immediate and remote aftereffects of this cumulation*
To make clear the mechanism or at least the essential feature
of the self-purification process of the landscape and its separate
elements, balance experiments are required* As a result of such
experiments on propanil (M.S.Sokolov et al., 1976) and MCPA
(Dr. D.Crosby, 1975) Important and interesting information was
obtained that permits to trace the fate of a herbicide in the
landscape and to even replanlhe strategy of its application* Evi-
dently, only the full-scale experiments can provide us with the
reliable data on pesticide residue transport with the surface and
subsurface runoff, as Well as with the data on self-purification
of the landscape and its elements. These are labour-consuming and
costly experiments that require careful preparation. Simultaneous-
ly we should not neglect important supplementary information that
is to be obtained through experimental ecotoxicological modelling
(M.S.Sokolov, 1975). Practically, only these methods will make us
43
-------
capable of solving the tasks of a multifactor experiment.
As. on the whole, the anthropogenic process of the transport
of pesticide residues in the landscape and the natural process of
self-purification are of an oppooitely directed and seasonally ex-
pressed character, it is extremely important to correctly forecast
the conditions limiting these processes* The role of the natural
complex process of self-purification can never be overestimated*
Therefores it is necessary, not only to study and develop the me-
thods of calculating the levels of maximum toxicant load-capacity
of the landscape (Tu.A.Izraelle, 1974) and the most favourable
conditions for self-purification (G.K.Gryzlova, 1Q75)t out also to
store the data on the laws of transport of various pollutants.
A well-known Soviet geochemist and geologist, academician
A.E.Foreman wrote that the phenomenon of transport of elements
appears to fee the most important object for geochemical research,
as it determines the whole association of the nature phenomena,
their diversity and peculiarities. In the same way, the research
in the field of ecotoxicology of pesticides and other xenobiotica,
examination of their fate, transformation, forms, pathways and
aechanisms of transport seem to us extremely important and nece-
ssary from the point of view of rational utilisation of the natu-
ral resources of biosphere and its conservation.
Reference
govda V.A. Changing Trends in the Biosphere and in Biogeochemi-
cal Cycles. Environmental Conservation, vol. 3, Bo.3,
p. 161. (&&)
Soderquist C.J., Crosby D.Gr^issipation of 4-chloro-2-methyl-
r^enoxyaeetic acid (MC2A) in a rice field. Pesticide science
vol. 6, Vo.1, p.17.
Sokolov M.S. et al. (1974). Rational use of water resources
and their protection from biocide pollution. EXPO*74,
World*s Fair, Spokane, USA, 5 p.
44
-------
AJIHSB A.I . ( Aliev, I.G>, 1976. B KH. "Xraaw noqs pucoaHX nojievi".
M., "HayKa", c.186.
AHOXMH B.JI. (Anokhin, V.L.), 1974. MoAejmpoBaHHe npoijeccoB
pa£Mon30TonoB B JnaHflina$Tax. M., ATOMMa^aT, c.I44.
icHH B.M. (Vernadski, V.lj, 1927. OtiepKH reoxHMMH. JI. ,
FOG. HSfl-BO.
M.A. (Glazovskaya, M.A^, 1972. TexHofiHoreowu - w
nporaoaa. BSCTHHK MocKOBCKoro yHHsepcHTem, IP 6, c.23.
jiOBa F.K.B flp. (Gryzlova, O.K. etaj, 1975. Cuocotf
rep6m;HflOB rpyrniK 3,4-JiJi. OTKFHTHH, HsodpeTeHHfl,
odpasqy. TOBapHHe 3HaKH, N? 33, c.6.
B.B. (Saitsev, V.3.), 19^5. PHCOsaa opocMTejibHaa
M., "Kojioc", c. 358.
K).A. (Izraelle, Yu.A.), 1975. KoMnjieKCHHii aHajin
. noAxo,im K onpeflejieHHK) ^onycTHMax HarpysoK Ha
cpe,Ey H o(5ocHOBaHne MOHHTOpuHra. B KH. "
25-29 wapra 1974 r.), JI.,
I -25.
B.A. ( Kovda, ?.A), 1973. PeoxHMHH no^BbodpasosaTejibHHX npo-
. B KH. "OCHOBH yqeHHH o noxjBax", q.E, 117^-199.
XHumecKHX ajieMeHTOB B noflseMHHX eo^ax CCCP ( "Migration of
chemical elements in ... USS£)I974. KojmewHB asTOpOB. M., 4HayKa",
c.128, 133-159.
HeBSOpOB M.M. , UiaHflHdHH B.E., COKOJIOB M.C. (Nevzorov, M.I., Shan-
dy bin, V.B., Sokolov, M. S. ), 1975. YcTpoviCTBO ,iyw OT6opa nopo-
BUX paCBBOpOB H3 nOTOGHHOPO C^OH H nOACTHJiaiC^MX TOpHSOHTOB.
, H3o6peT6HHflf npoMuoiJieHHbie oOpaai^bi H Tosapme
y fi? 31.
A.M. (Perelman, A.I.}, jg/3. reoxmoifi 6HOC$epu. M., "HayKa
c.166.
45
-------
COKOJIOB W.C. ( Sokolov, M.S), 1975. 3jieweHTH 8KOTOKCHKOJiornqecKoii
MOflejiH 9Kcnpeco-H3y?eHHs cyAi>6u djioipwoB B jjanipaipTe. 3 KH.
"IfexaHMSM fleiiCTBiw repdHmwoB H cMHTeTiwecKHX peryjiflTOpos pocxa
pacTeHHH H MX cy#b6a B 6noc$epe", ^.H, nynpmo, c.71.
COKOJIOB M.C. H ,np. (Sokolov, M.S. et aaj, 1974. llOBeAeHMe HCKOTOpux
B yCJIOBiiaX pHCOBOK OpOCHTejIbHOVI CHCT6MU.
COKOJIOB M.C. H .Tip. (Sokolov, M.S. etai), 1975. Oco6eHHOCTH
nponaHnna, HJiana, 2M-4X, 2,4-^0, B picoBux opocHTejibHHX cMCTeitax
..yoaHH. XHMUS B cejitcKOM XOSSMCTBC, N? 3.
COKOJIOB M.C. H Ap. (Sokolov, M.S. et a3), 1976. HcweanoBeHHe H wnrpa-
H ero MeTa6ojiMTa 3,^-flnxjiopaHHJiHHa B opomaeuow
. iiss. AH XCP, cep, dHOJionraecKaa, HS 2.
COKOJIOB i*i.C., fcmp JI.J1., HydeHKO A. II. (B neqaTu) -(Sokolov, M.S. et
Tep6HUi«H B pHGOBOflCTse. M. , "Hayica11, al.) -» in press
Ci-peKOsoB E.fl. H Ap. (Strekozov, B.P.etal), 1974. MwrpauHa H npespa-
nponaH.Hfla B PHCOBOM opocHTeju»Hoii CHCTeiie. BojuieTeHt Hayqno-
HHcpopwautm BcecojosHoro HayqHO-HCCwieAOBaTejiBCKoro
pica, BHD. XQ, c.33.
B.n., fytieHKO A.O., COKOJIOB M.C. (B neqaTH) - (&«vokocovt
B.P. ). MnrpauHH H pacnpe^ejieHHe ocTaTKOB nponannna B AOHHUX
flpnasoBCKHX jotMaHos. MaeecTHfl AH CCCP, cep. 5nojiorH-
A.H. ( TJurjukanov,A.H), 1964.
oapbepu H MX pojib B unrpai;iQi XHMJWGCKKX ajieMeHTOB B reorpa-
$mecKoti o6ojio^ace SSMJIM. MSB. Bcec. reorpa$.o6at-Ba, N^ 4.
A.E. (Persman, A.B^, 1933-1939. PeoxMLOia,. T. 1-4, JL,
A.D., CTPSKOSOB B.n. (Chubenko, A.P., Strekozov, B.P),
I9>6. MMrpamw anaHa s ycjiOBHax PHCOBHX opocHTeJibHux
B jejibCKOM xos^CTBe* ^ 9, c.69.
46
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CERTAIN LAWS OF ORGANOCHLORINE PESTICIDE REDISTRIBUTION
IN THE SOIL-WATER, SOIL-PLANT SYSTEM
G. G. Zhdamirov, E. E. Popov, and N. F. Lapina
Institute of Experimental Meteorology, Obninsk
It has been known that organochlorine pesticides are used by
man for about 25-35 years, first - as a means for combatting insects-
carriers of diseases of people and domestic animals and then - for
plant protection on a large scale. Rather recently, as highly sen-
sitive methods of analysis are mastered, the scientists have con-
centrated their attention on the fact that pesticide residual amo-
unts are globally being found everywhere - in plants, soil, water,
birds, fish, and air. During the years that followed a danger of
further environmental contamination with stable pesticides caused
certain limitation (and for DDT - a ban) of their use and led to
the widescale scientific search for understanding the process of
transfer of these pesticides in the environment, their fate in va-
rious phases of the environment, and their hazard for man and biota
as a whole*
Organochlorine pesticides belong to those chemicals which are
the most persistent in the environment. This property primarily ac-
47
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counts for the fact of their global finding in all phases of the en-
vironment. Studies of the pesticide dynamics in the cycle
I I
water -*~ soil -*~ air
biota
and acquisition of the quantitative characteristics of their redist-
ribution in various phases are of evident interest, first - from the
viewpoint of predicting variations of the levels of pesticide resi-
dual amounts in the media mentioned, and second - because in the
long run it will provide more information on pesticide persistence
in the environment as a whole. In the cycle being considered soil
is the major component of the biosphere determining the adjacent
medium contamination.
This paper presents the experimental data on pesticide evapora-
tion from water and soil, and their transport into plants. Investi-
gations were carried out with the pesticides which had been most
widely used in the previous years, their physical and chemical pro-
perties being well studied, such as DDT and BHC. In the last few
years the process of pesticide evaporation from soils and various
surfaces has received considerable attention. It has been found that
evaporation and vapor-phase transport are important elements of dis-
sipation even of the so called non-volatile pesticides, such as DDT,
dieldrin, and others. We set a problem - to find the simplest method
48
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of estimating pesticide evaporation from soils, water, and surfaces.
Earlier it has been found that the rate of pesticide evaporation
from the moist soils and moistened surfaces is considerably higher
than that without moistening fl-^l • Acree and co-workers p,6J found
that DDT is capable of co-evaporating in considerable amounts with
the water from water solutions. These and other works indicate that
apparently, the rate of pesticide evaporation can be determined quan-
titatively from the rates of water evaporation from the surfaces of
soil, water, and other objects.
In the first stage of work we have obtained a quantitative as-
sessment of the DDT and BHC evaporation from the water solutions.
The DDT and BHC concentrations in water were investigated over the
range I to 130 mg/1 for DDT and O.I to 1000 mg/1 for BHC. The expe-
riments were carried out in the thermostatic vacuum installation.
The products of evaporation were freezed out in the trap being
cooled by liquid nitrogen. The pesticides were extracted by n-hexane
and analyzed by the method of gas-liquid chromatography. Over the
range of low DDT concentrations the experiments were conducted with
T/l
the x C-labeled pesticides. The results obtained are presented in
Figures I and 2. It is evident that the curves of relationships bet-
ween the evaporated pesticides per gramm of water and their concent-
rations in water have two distinctive portions: one adhered to linear
dependence on pesticide concentration in water and the other indepen-
dent of it, that is the portion of saturation. The amounts of co-eva-
porated pesticides per gramm of water on the portion of saturation
at 20°C are 0.31, 12.6, and 42 ug for p^'-DDT, ^-BHC, and
-------
respectively. For this portion, our experimental data are rather
adequately correlated with the values calculated theoretically with
the known relationship which is used in steam distillation of two
mutually insoluble liquidst
MAPA
•B
where W,M, and P are the weight, molecular weight, and pressure of
pesticide and water saturated vapor, respectively.
OJ
o
H
2.0 -
1.8 -
1.6 _
P.
P
60
1.0
s * • * •—r
0 0.5 1.0 1.5 2.0 2.5
logIO(mg p,p'-DDT/1 H20)
Figure I. Co-evaporation of p,p'-DDT with water at various
temperatures (triangles - radiometric method of
analysis, circles - chromatographic method).
50
-------
o
t\J
« 2
to
I
bC
o
o o
_? • • oC - BHC
2 3
logIO(mg BHC/1 H20 x 10)
- BHC
Figure 2. Co-evaporation of (P -BHC and oi -BHC with water at 20°C,
-------
The temperature characteristic of the p,p*-DDT co-evaporation
on the portion of saturation over the temperature interval 10 to 40°C
shows that this formula is well satisfied already over the range JO
to 40°C (Table I).
Thus, our data did not confirm the results obtained by Acree and
Bowman, namely the alleged 3-8-times increase in co-distillation of
DDT with water. When calculating the pesticide loss by evaporation
from the water solutions based on the amount of evaporated water,
it is necessary to take account of both portions, respectively, pro-
ceeding from their concentrations in water.
The field measurements of the DDT evaporation rate under its
surface application in the soil showed that on the first day the
average rate of DDT loss through evaporation amounted to approxi-
mately one percent per hour at the rate of 2 kg/ha. DDT applied in
the 10 cm soil layer disappeared at the rate which was characterized
—2 —T
by the first order process with the constant of 5*10 day . So
large a value of the constant is possibly accounted for by the sub-
stantial soil loosening and climatic conditions of the process be-
ing studied.
The other direction of our investigations is to determine the
quantitative characteristics of pesticide transport into various
species of plants and their distribution in the aerial and root
parts of plants depending on their content in soil.
The problem of pesticide sorption by plants from soils was dis-
cussed in several publications [?-s], this problem being considered
from the viewpoint of both hygienic rationing of pesticide appli-
52
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Table I. Theoretical and experimental values of the co-evaporation of p.p^-DDT, J"-BHC,
and Ct-BHC with water
Ul
U)
Pesticide
p,p'-DDT
p,p'-DDT
p,p«-DDT
p,p'-DDT
f-BHC
d-BHC
Temperature ,
°C
10
20
30
40
20
20
Pesticide
vapor
pressure ,
mm Hg
2.61 x I0~8
1.48 x I0~7
7.18 x I0~7
3.23 x IO"6
9.4 x lO"6
_
Water
vapor
pressure,
mm Hg
9.2
17.4
31.6
54.9
17.4
17.4
Co-evaporation,
theoretical
( calculated
with equation I)
0.056
0.16
O.44
1. 15
8.76
-
mfcg/g o^O
experimental
0.17
0.31
0.58
1.02
12.8
42
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cation and their metabolism, accumulation in plants, etc. However,
there are rather few quantitative assessments characterizing the
degree of pesticide sorption by plants depending on the levels of
their concentration in soil. The work by Voerman and Bessemer [9]
appeared to be one of the most significant in this field. The au-
thors provided a quantitative information on the degree of sorption
of several pesticides (dieldrin, lindane, DDT) from the soil by
plants (grass) and their distribution in the aerial and root parts
of plants.
Our experimental data are concerned with the sorption of DDT
and related compounds by such plants as barley and clover. The con-
centrations of DDT and related compounds were investigated over the
range 2 to 8 mg/kg of soil, technical DDT containing 74.3# PiP'-DDT,
22^21 o,pf-DDT, p,pf-DDD, and J>.7%> p,p'-DDE. The experiments were
carried out in the vegetative pots with three repetitions. In a
month for barley and in two months and a half for clover the samples
of soil and plants were collected, the vegetation being analyzed
in parts: roots and green mass.
The results of investigations are given in Tables 2,3 and in
Figures 3,4. They indicate that the degree of the DDT and related
compounds entering the plants depends on the rate of pesticide ap-
plication into the soil. The pesticide accumulation in the green
mass of plants slightly varies over the range of rates being stu-
died - within the limits of 6-1595 (in relative units of the51 DDT
per kg of green mass to the^DDT per kg of soil). A picture of tha
root system sorption is completely different. The ratio of concent-
54
-------
Table 2. Dependence of the DDT products accumulation (mg/kg of dry weight) in
roots and stems of barley on the rates of pesticide application in the
soil. Duration of the experiment is I month.
Rate of
application,
mg/kg of soil
2
4
6
8
Object of
investigation
Soil
Hoots
Stems
Soil
Roots
Stems
Soil
Roots
Stems
Soil
Roots
Stems
p,p'-DDT
1. 00
7.21
0.24
2.04
19.71
0.20
5.16
34.4
O.II
4.52
57.5
0.55
o,p'-DDT
plus
p,p'-DDD
0.55
2.68
0.04
0.67
8.40
0.05
1. 15
15.3
0.08
1.53
24.2
0.12
p,p'-DDE
0.04
0.18
0.02
0.06
0.78
O.O2
0.09
1.53
0.03
0.17
2.50
0.03
XDDT (roots) 21 DDT (roots)
rate of application ]>IDDT (stems)
5.03 33.6
7.22 100.7
8.55 160.0
10.55 169.0
-------
Table J. Dependence of the DDT products accumulation (mg/kg of dry weight) in
roots and stems of clover on the rates of pesticide application in the
soil* Duration of the experiment is 2.5 months.
Bate of DDT
application,
mg/kg of soil
2
4
6
8
Object of
investigation
Soil
Roots
Stems
Soil
Roots
Stems
Soil
Roots
Stems
Soil
Roots
Stems
p,p'-DDT
1. 18
6.1
0.18
1.67
15.0
0.13
3.II
29.3
0.15
4.4
44.0
O.I?
o.p^-DDT
plus
p,p'-DDD
0.37
2.6
0.04
0.61
7.6
0.03
0.79
12.7
0.06
1.8
19.3
0.06
p.p'-DDE DDT (roots)
rate of application
0.037 4.5
0.32
0.02
0.08 5.9
1.0
0.012
0.16 7.4
2.4
0.013
0.21 8.3
3.1
0.02
DDT (roots)
DDT (stems)
37.5
I3B.O
201.8
265.8
-------
rations of the sum of DDT products in roots to those in soil which
is conventionally called the transport coefficient increases in a
greater degree as the content of these products in soil increases.
The data obtained by the authors mentioned above are shown in Fi-
gure 3 as triangles (the calculation has been performed by us). It
is seen from the tables that the ratio of the DDT concentrations
in roots to those in stems noticeably increases with the rates of
pesticide application into soil and ranges from 33.6 to 169.0 units
for barley and from 37«5 to 266.0 units for clover.
12 _
I
10
a
•p
o
s
0
•H
g
n
w
rH
•H
o
m
a.
•H
§
p
N
6 -
0.5
1.0
DDT in soil, mg/kg
1.5
Figure 3. Dependence of the coefficient of DDT and related
compounds transport (accumulation) in the roots
of barley and clover on their content in the soil
(I - for barley, 2 - for clover).
57
-------
60 r
50
o
8
S
20
10
21 ofp'-DDT, p,p'-DDD
I
r
p,p'-DDT
Figure 4. Accumulation of the DDT products in the roots
of "barley and clover depemding on their con-
centrations in the soil:
I - for barley (duration of the experiment is I month);
2 - for clover (duration of the experiment is 2.5 months),
58
-------
Figure 4 indicates that accumulation of p,p*-DDT and the sum
of o,p*-DDT and p,p*-DDD occurs at different rates as their concent-
rations in soil vary.
Analysis of the soil for the content of DDT products in it be-
fore and after an experiment indicates that over the time of the
experiment their percentage composition did not practically changed.
However, over the time of the experiments the loss of pesticides
from the soils amounted to approximately 25f%. It is possible that
these losses are due to the process of evaporation.
Comparison of the results of our investigations with the data
obtained by Voerman and others for different soils and species of
plants as well as under different experimental conditions shows
that either the mechanism of the DDT products entering the roots
of plants from the soil is likely to be independent of the experi-
mental conditions, types of soils, and species of plants or these
conditions were similar. Further investigations at various types
of soils and species of plants will provide opportunities to draw
an appropriate conclusion about that.
Thus, using barley and clover as the objects of investigations
we found that DDT and related compounds are mainly accumulated in
theroot system of plants.
59
-------
References
Til W. P. Spencer, W. J. Parmer, and M. M. Cliath. Pesticide
volatilization. Residue reviews, 49, 1-4? (1974).
J2J W. J. Parmer, J. Letey, Volatilization losses of pesticides
from soil. EPA-660/2-74-054 (1974).
[3] W. D. Guenzi, W. E. Beard. Volatilization of lindane and DDT
from soil. Soil Sci. Soc. Amer. Proc. 34. 443 (1970).
[4] E. P. Lichtenstein, K. R. Schulz. Effect of soil cultivation,
soil surface and water on the persistence of insecticidal
residues in soil. J, Econ. Ent. 34. I03f 517 (1961).
[5] M. C. Bowman, P. Jr. Acree, C. H. Schmidt, and M. Beroza.
Pate of DDT in larvicide suspensions* J. Econ. Ent. 52.
1038 (1959).
[6] P. Jr. Acree, M. Beroza, and M. C. Bowman. Codistillation
of DDT with water. J. Agr. Pood Chem. II, 278 (1963).
[7] E. S. Kovaleva, G. A. Talanov. DDT absorption from soil and
its translication into stems and leaves of plants. Khimiya
v sel'skom khozyajstve 8, 26 (1972).
N. Rosa, H. H. Cheng. Distribution of DDT - I4C in Nicotiana
Tabacum. Can. J. Plant Sci. ^4, 403 (1974).
[9] S. Voerman, A. P. H. Besemer. Persistence of dieldrin, lindane
and DDT in a light sandy soil and their uptake by grass. Bull.
Environ. Contam. and Toxicol. 13. 501 (1975).
60
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PESTICIDE TRANSPORT AND METABOLISM IN MODEL SYSTEMS
Donald D. Kaufman, Philip C. Kearney and Ralph G. Nash
U.S. Department of Agriculture*
Laboratory studies devoted to investigating the environmental fate of
pesticides have usually examined individual processes such as microbial metab-
olism, soil leaching, surface and vapor phase photodecomposition, volatiliza-
tion from plant or soil surfaces, and plant uptake. In the environment, how-
ever, all of these processes may be operative on the molecule, so that in
each stage of the pesticide dissipation process, one or more processes may
play a major role. It has been extremely difficult to study two or more of
these processes under controlled conditions which will enable a clear under-
standing of the contribution of each. Simplified model laboratory systems
are now being developed which enable simultaneous measurement of numerous
factors affecting pesticide dissipation in the environment.
BIOLOGICAL AND CHEMICAL ASSAYS
Biological and chemical assays have been primarily used to study persis-
tence, adsorption, and movement of pesticides through soil, and the effects
of various soil and environmental conditions and properties on pesticide be-
havior in soil. Chemical assays are useful in both quantitative and qualita-
tive determinations of pesticide residues, but are generally limited by the
ability of the solvents to extract the residues from soil. Chemical analyses
for pesticides and their degradation products in the environment was for a
long time one of the major stumbling blocks in pesticide research. With the
development of new instrumentation and procedures it is now possible to deter-
mine quantities of pesticides as low as a few parts per billion. Spectropho-
tometric and chromatographic instruments have become the major analytical
tools in determining pesticides and their degradation products.
Bioassays are generally used as a quantitative measurement of the bio-
logically active concentration of a pesticide known to be present. Bioassays
involve the measurement of a biological response by living plant, microbe, or
animal organisms in order to determine the presence and/or concentration of
chemical in a substrate. For example, a soil bioassay involves the growing
of an indicator organism in a pesticide treated soil, and then comparing the
response of the test organism to similar organisms cultured in untreated soil
or in soil containing known pesticide concentrations. Two basic assumptions
are made when using bioassays: (a) that the organisms show increased injury
in an order related to the pesticide concentration; and O) that the responses
obtained are reproducible.
*Pesticide Degradation Laboratory, Agricultural Environmental Quality
Institute, ARS, USDA, BARC-West, Beltsville, Maryland 20705.
61
-------
Bioassays and chemical-physical assays each contribute information of
value and each are useful for certain circumstances. A major advantage of
the bioassay is the assurance that the toxic activity of the pesticide mol-
ecule is what is being measured. It is not usually necessary to extract the
pesticide from the substrate, thus circumventing the problems involved with
the extraction procedures that are often needed for chemical assays. Bio-
assay procedures are usually more economical, less difficult to perform, and
do not require as much expensive equipment as chemical and physical analyt-
ical methods. However, there are also difficulties in using organisms to
bioassy for pesticides that must be considered when developing or using a
bioassay. Growth is directly influenced by ambient environmental conditions
such as light, temperature, watering method and level, and humidity. Varia-
tions in these factors may cause a greater biological response than the pes-
ticide under test. Thus, the environmental and edaphic factors must be very
closely controlled. Untreated organisms and known standards should be in-
cluded each time an assay is conducted. Species variation in susceptibility
to a given pesticide; and in some instances individual organism variation
within a species may also be apparent. A comprehensive guide to bioassay,
adsorption, absorption, leaching, and microbial interaction methodology has
been published (1).
SOIL PERFUSION
Soil perfusion devices have been developed to study soil microbiological
processes such as nitrification, denitrification, pesticide degradation, and
microbial ultilization of water-insoluble substrates such as sulfur or coal
C2). The design shown in Figure 1 is equally adaptable to either positive or
negative pressure systems. It has been used successfully with C02 traps both
preceding and succeeding the system. Its principle advantages are: Ca) adapt-
ability to use with either positive or negative pressure systems; (h) ease of
maintaining sterility if desired; (c) ease of sampling perfusate; (d) ease of
controlling rate of perfusion; (e) adaptable to use with gases of known com-
position; (f) infrequent adjustment requirements; (g) self-supporting and com-
pact design; and (h) relatively inexpensive parts.
This system has been used successfully to observe microbial degradation
of pesticides (3,4). In such investigations, soils containing a pesticide
were perfused with distilled water; or untreated soils were perfused with
aqueous solutions of pesticides. Under these conditions degradation was deter-
mined either by measuring the rate of pesticide disappearance, or the accumu-
lation of breakdown products, or by both. The kinetics involved with the
degradation of a pesticide in similar systems have been discussed elsewhere
C5,6). Typically, a lag period occurs during which there is no change in
pesticide concentration, followed by a period of rapid disappearance of the
pesticide (Figure 2). Subsequent additions of the pesticide decompose more
rapidly than the first. This period of rapid breakdown is generally accompan-
ied by proliferation of "effective" microorganisms capable of utilizing the
pesticide as a sole or supplemental source of energy and carbon. Soils in
which this phenomenon has occurred are frequently described as "enriched"
soils C5)• Isolation of pure cultures of effective organisms from enriched
soils has been achieved via dilution plate techniques.
62
-------
Data obtained with soil perfusion units have been primarily useful in
assessing the relative biodegradability of pesticides (5,7); factors affec-
ting microbial degradation of pesticides; microbial degradation of pesticide
combinations (4); and soil enrichment and subsequent isolation of effective
microorganisms. Other techniques are necessary for studying cometabolic or
chemical processes involved with pesticide degradation in soil (8).
SOIL BIOMETRY
Several systems have been used to study degradation and metabolism of
14C-pesticides in soils. Two of these methods have been used extensively
in our laboratory. Although either system can be used to study pesticide
metabolism by isolated organisms, they are more commonly used with the total
microbial population in soil considered as a tissue or unit organism. One
system involves a "soil biometer" flask developed by Bartha and Pramer (Fig-
ure 3) (9). When 14C-labeled pesticides are incorporated into the soil, the
apparatus and method of analysis enable both ^££>2 an^ total ^2 production
to be monitored at frequent intervals for prolonged periods, and all meas-
urements are made on the same soil sample without significant exposure to
atmospheric (X>2. Although it was suggested by the developers that the mag-
nitude of the difference in amount of C02 produced by treated and untreated
soil could be used as a measure of the extent to which an unlabeled pesti-
cide molecule was oxidized, this approach may be inaccurate with pesticides
which stimulate microbial activity in addition to serving as a substrate.
Consequently, use of C-labeled pesticides provides a far more accurate
indication of actual pesticide metabolism in soil.
The soil biometer flask has been used successfully to study microbial
metabolism of numerous pesticides in soil. A serious limitation of this
technique, however, may be encountered when volatile pesticides which can be
trapped in base are examined in this system. It then becomes essential to
determine by organic solvent extraction or precipitation of evolved C02, how
much of the 14C material trapped in the base is actually 14C02 or volatile
14C-pesticide residues. This problem is avoided in a system developed by
Kearney and Kontson (10).
The system of Kearney and Kontson (10) permits simultaneous measurement
of pesticide loss by volatilization and metabolic C02 evolution from soils
(Figure 4). The system is maintained with an air flow which flushes evolved
C02 and volatilized pesticide residues from the incubation flask. Each flask
is equipped with a polyurethane foam plug held in a sintered glass filter
funnel. This apparatus was used to examine vapor and metabolic loss of two
dinitroaniline herbicides from soil (Table 1). A comparison of the KOH traps
revealed no difference in the amount of ^4C02 trapped in the presence or
absence of the polyurethane plugs. Analysis of the plugs divided into four
sections showed that 97% of the butralin volatilized was recovered in the
first centimeter of the plug and 1% of each of the remaining three 1-cm
sections. Extraction of the KOH solutions with ethyl acetate revealed that
no butralin escaped through the plug. Results obtained with this system
indicated that loss of trifluralin by volatility from soil surfaces was the
major loss mechanism during the first three weeks after application (Table 1)
CIO).
63
-------
Before the system can be used with other pesticides, the trapping char-
acteristics of the plugs should be tested. The system was easy to maintain
although the soils lost moisture during the time between weekly samplings.
This can be remedied, however, through the use of humidified air. It was
suggested that studies on vapor phase photolysis might also be feasible in
the system.
ROOT VS VAPOR SORPTION METHODOLOGY
Crops can be contaminated aerially by intentional, direct application
of pesticides or by indirect ways such as spray or dust drift and wind-borne
pesticide-treated soils. Some pesticides are root-absorbed directly from
treated soil, then translocated to aerial portions of plants. Another pos-
sible pathway of contamination is pesticide vaporization from soil and sorp-
tion of these vapors by aerial portions of plants. Barrows et al. (11) found
that the leaf-to stalk ratio of dieldrin concentrations in field-grown corn
was about 50 times higher than the ratio found in insecticide vapor-protected
plants grown in a greenhouse. They attributed this large difference to
aerial contamination of the field grown corn.
Beall and Nash (12) developed a system for distinguishing between pesti-
cide contamination of plants resulting from root sorption and plant sorption
of the pesticide vapors emanating from the soil Cpigure 5). Surface and sub-
surface soil layers are separated by a water- and vapor-tight disk. To con-
fine vapors around the plant, a polyethylene cage Open at the top) is pro-
vided. In any given pot only one pesticide is used, and only one of the soil
layers is treated with pesticide. A hole (.fitted with a piece of glass tub-
ing) in the center of the disk allowed the plant stem to pass through the
upper layer without touching the soil.
In experiments with several 14C-labeled insecticides they observed that
regardless of the insecticide treatment, contamination of aerial plant parts
occurred through both root and vapor sorption (Table 2). Although their re-
search was performed under greenhouse conditions, the results indicated that
insecticide volatilization from treated soil may be as important Cdieldrin)
or more important (DDT) than root uptake as a mechanism of crop contamination
under field conditions. Actually, under field conditions, where roots are
able to penetrate down into untreated soil, volatilization may be an even
more important mechanism of contamination than their pot experiments demon-
strated. Results from such a method contribute to a better understanding of
the nature of root sorption and vapor sorption of pesticide residues by plants
and their fate and behavior on or within the plant.
AGROECOSYSTEMS
Recently, agroecosystem chambers have been developed in which the com-
bined effects of all pesticide dissipation processes can be studied (Figure
6) (13). Agroecosystems allow for independent study of dissipation processes
in soil, plant, air, and water as a function of time. The agroecosystem shown
here has a number of advantages, i.e. it is relatively inexpensive, easy to
operate, monitor, and sample; versatile in the number of plants and soils
that can be studied; adjustable to rainfall and potentially adjustable to
64
-------
wind velocity, light intensity and duration; and conducive to balance stud-
ies where pesticide mobility can be compared under similar conditions. It
has an advantage over previous systems because the large air exchange pro-
vides cooling, prevents moisture condensation on the chamber walls, and per-
mits sufficient air sample volumes for measurement of very low residue concen-
tration. The aerial residues in the exhaust air are trapped on polyurethane
foam plugs, which are sampled periodically. Numerous other environmental
factors such as temperature and relative humidity inside the chambers are
monitored periodically with automatic equipment.
In initial investigations when toxaphene and DDT were applied to cotton
in the agroecosystem chambers, 24 and 15%, respectively, were lost to the air;
20 and 24% were in the surface 1 cm of soil; and the rest remained on the cot-
ton plants over a 90-day period. Calculated half-lives in air for toxaphene
were 15.1 days, and 19.8 days for p,p'-DDT. More detailed accounts of these
results have been published (14).
Initial objectives have been to test the ability of the agroecosystem for
comparing the mobility of different classes of pesticides and thereby identi-
fying potential environmental problems. Long-term objectives are to explore
the possibilities of determining bioaccumulation of pesticides in terrestrial
organisms and interfacing the agroecosystem with other model ecosystems, par-
ticularly the aquatic ecosystem. An ultimate objective is to devise methods
of reducing pesticide mobility.
REFERENCES
1. Wilkinson, R. E. Research Methods in Weed Science. POP Enterprises,
Inc., Atlanta, Georgia, and Creative Printers, Griffin, Georgia. 198
pp. 1972.
2. Kaufman, D. D. An inexpensive, positive pressure soil perfusion system.
Weeds 14:90-91 (1966).
3. Kaufman, D. D., and P. C. Kearney. Microbial degradation of isopropyl
N-3-chlorophenylcarbamate and 2-chloroethyl N-3-chlorophenylcarbamate.
Appl. Microbiol. 13:443-446 (1965).
4. Kaufman, D. D., P. C. Kearney, D. W. Von Endt, and D. E. Miller. Methyl-
carbamate inhibition of phenylcarbamate metabolism in soil. J. Agr. Food
Chem. 19:513-519 (1970).
5. Audus, L. J. Microbiological breakdown of herbicides in soils, pp. 1-18.
.In. Herbicides and the Soil. F. K. Woodford and G. R. Sagar, eds. Black-
well Sci. Publ., Oxford. 1960.
6. Kaufman, D. D., and P. C. Kearney. Microbial transformation in the soil.
pp. 29-64. ^Herbicides: Physiology, Biochemistry, and Ecology, Vol. 2.
L. J. A.udus, ed. Academic Press, London. 1976.
7. Kaufman, D. D. Structure of pesticides and decomposition by soil micro-
organisms. In Pesticides/Soils/Water. ASA Special Publ. No. 8, pp.
85-94. 19667~
8. Kaufman, D. D., J. Plimmer, P. C. Kearney, J. Blake, and F. S. Guardia.
Chemical vs. microbial decomposition of amitrole in soil. Weeds
15:266-272 (1968).
• Bartha, R. and D. Pramer. Features of a flask and method for measuring
the persistence and biological effects of pesticides in soil. Soil
Sci. 100:68-70 (1965).
65
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10. Kearney, P. C. and A. Kontson. A simple system to simultaneously measure
volatilization and metabolism of pesticides from soils. J. Agr. Food
Chera. 24:424-426 U976).
11. Barrows, H. L., J. H. Caro, W. H. Armiger, and W. M. Edwards. Contribu-
tion of aerial contamination to the accumulation of dieldrin by mature
corn plants. Environ. Sci. and Tech. 3:261-263 (1969).
12. Beall, Jr., M. L. and R. G. Nash. Organochlorine residues in soybean
plant tops: Root vs. vapor sorption. Agron. J. 63:460-464 (1971).
13. Beall, Jr., M. L., R. G. Nash, and P. C. Kearney. Agroecosystem - A
laboratory model ecosystem to simulate agricultural field conditions for
monitoring pesticides, _In_ Proceedings of the Conference on Environmental
Modeling and Simulation. W. R. Ott, ed. U.S. Environmental Protection
Agency, Cincinnati, Ohio, April 19-22, 1976. pp. 790-793.
14. Nash, R. G., M. L. Beall, Jr., and W. G. Harris. Toxaphene and DDT
losses from cotton in an agroecosystem chamber. J. Agr. Food Chem.
25:336-341 (1977).
Table 1. Vapor and Metabolic Loss of Butralin and Trifluralin
from Matapeake Silt Loam (10).a
Trapped 1**C as •
\ of total
Butralin
Week
1
2
3
Totals
Plugs
0.45
(82)
0.43
(84)
0.37
(72)
1.25
1I+C02
0.10
(18)
0.08
(16)
0.15
(28)
0.33
Total
0.55
0.51
0.52
1.58
Plugs
4.42
C95)
0.86
(81)
1.16
(69)
6.44
applied
Trifluralin
^C02
0.18
C5)
0.20
(19)
0.49
(31)
0.87
Total
4.60
1.06
1.65
7.31
01 Since there was no difference in the amount of J1*C lost as
volatile products in the light or dark, the values presented
represent averages of four replications. Numbers in parenthe-
ses indicate percent *kC appearing in plugs and C02.
66
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Table 2. Gas-liquid chromatographic determination of insecticide
residues found in various parts of soybean plants exposed
to soil treated with ^C-DDT, -dieldrin, -endrin, or
-heptachlor (12).
Source of contamination
Insecticide
residues
DDT
DDE
ODD
Total
Dieldrin
Endrin
Endrin ketone
Total
Heptachlor
Hydroxtchlordene
Heptachlor epoxide
Total
Vapor sorption Root sorption
Leaves
10.35
1.97
0.11
12.43
18.87
12.28
-
12.28
0.42
0.10
0.44
0.96
Stem
0.78
0.08
0.03
0.89
2.11
0.78
-
0.78
0.60
0.03
0.21
0.84
Seeds Leaves
ppm
DDT
0.00 0.01
0.00 0.01
0.00 0.00
0.00 0.02
Dieldrin
0.73 6.43
Endrin
0.31 23.86
0.01
0.32 23.86
Heptachlor
0.08 0.10
0.00 0.87
0.25 1.37
0.33 2.34
Stem
0.00
Trace
0.00
Trace
104.91
173.99
_
173.99
3.16
0.85
27.33
31.34
Seeds
0.00
0.00
0.00
o.ao
0.71
0.09
0.15
0.24
0.02
0.04
0.34
0.40
67
-------
SOIL
GLASS WOOL
AIR OUTLET
SAMPLING
PORT
DELIVERY TUBE
-AIR INLET
•RESERVOIR
Figure 1. Diagram of soil perfusion unit (2)
68
-------
100
8
Figure 2. Microbial degradation of dalapon in (A) an untreated
soil perfused with an aqueous solution of dalapon; and
CB) the same soil, re-perfused with a second supply of
aqueous dalapon (2} .
69
-------
Figure 3. Soil biometer flask (9),
70
-------
polyurethane-
foam plug
soil
Figure 4. Diagram of system designed to
measure volatilization and
metabolism in or on soils (10)
71
-------
0.92m
15.2cm
SPACE
SOIL
WIRE MESH CYLINDER
WRAPPED WITH
POLYETHYLENE FILM
POLYETHYLENE
SEAL
GLASS TUBE
SOIL
FIBERBOARD
DISK
AIR HOLE
PLASTIC POT
SAUCER
Figure 5.
Longitudinal section of pot designed
to provide a solid, liquid, and vapor
barrier between surface and subsur-
face soil treatments (12).
INLIT Nllll MOtOII / |
ftfg ^mi£®Mi
OUTUI Flllll MOIOII
Figure 6. Diagram of an agroecosystero (14).
-------
COMETABOLISM OF FOKEIQS! COMPOUNDS
Golovleva L.A., Skryabin G.K.
Institute of Biochemistry and Physiology of Microorganisms
A characteristic feature of the most part of present investigations
on inicrobial degradation of xenobiotic compounds is the absence of certain
idea about ways of practical application of microbiological methods. Analysis
of up-to-date situation shows a distinct discrepancy between laboratory
science trends and conceavable technology of practical realization of obtained
results.
The main attention of the scientists is paid to isolation of microorga-
nisms capable to use xenobiotics as a sole carbon sources under traditional
laboratory conditions - pure culture, high aeration, optimal temperature and
so on.
These "classical" approaches resulted many times in disappointments at
the attemps to apply cultures, obtained at the laboratories for degradation
of xenobiotic in natural habitats.
So, Andersen tried to use a fungal culture Mucor alternans, capable to
transform DDT into water-soluble products under laboratory conditions for
degradation of this pesticide in soil. He did not receive desirable result.
The explanation was that natural soil microflora interfered with function
of introduced culture.
73
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We tried to introduce the bionass of cultures degrading ordram into
a water of a natural reservoirs, contaminated by this herbicide. The applied
cultures were Pseudononas aeruginosa and Bacillus sp.isolated from water
habitats, contaminated by ordram a year before. In both of the experiments
the introduced cultures disappeared completly in 24 hours or near that.
According to prof.Zwjaguinzev, bacterial cultures should be introduced
into the soil not less than 1 t per hectare to obtain a positive effect in
xenobiotic content decrease.
The positive experience known concerns to hydrocarbon decomposing
microorganisms. The experiments on degradation of petroleum products,
contaminating soils were carried out by american scientists and are well
known. It should be mentioned, however, that was the most simple case,
because petroleum hydrocarbons are oxidized by many naturally occuring
microorganisms, and besides, the inoculums of microbial mass were rather
heavy.
Thus, taking into account these considerations, one can conclude, that
microorganisms, obtained at the laboratories, can be applied in the first
line in so called intensive methods suggesting the construction of special
installations of industrial type, where the microorganisms could be applied
as a components of active sludges or in some immobilized (fixed up) form.
For degradation of xenobiotics, accumulated in the biosphere at the
vast aeriaes of soils or waters, one needs another approuches-extensive ones,
which don't requirer creating of complicated technological schemes of
industrial scale. The introduction of foreign microorganisms into soils or
water is hardly suitable way to solve this problem. The required quantities
of microbial mass should be too great and the effect is too transient. To
74
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obtain a stable permanent effect, one has to solve quite another problem,
in fact creating of new, artificial ecosystem. That's why from our point of
view, the more proper approach to extensive methods of xenobiotics degrada-
tion is a mobilization of capacities of natural microflora.
There are at least taro ways to do that - the first one - supplying of
natural microflora by N and P sources (this was demonstrated by american
authors in case of petroleum contamination of the soil) and the second -
method of conetabolism.
These approachs make possible extensive methods of microbiological
degradation of xenobiotics in the environment.
Study of cooxidation of aromatic hydrocarbons and heterocyclic compounds
by microorganisms at the expense of other compounds - hydrocarbons, carbo-
hydrates etc.has drawn the attention of microbiologists to the regulations
of interaction between microorganisms and some other substrates (Hbrwath,
1972; Skryabin, Golovleva, 1976). It is stater that fermentative conversions
of many organic substances are closely connected or even depend on oxidation
of other compounds - cosubstrates. This dependence is generally called
cometabolism.
There is no strickt definition of the notion "cometabolism11 and different
authors treat it differently.
Some investigators-specialists in the field of soil microbiology-
Alexander, Horvath consider cometabolism to be transformation processes i.e.
partial conversion carried out by microorganisms, growing or grown on
substrates inducing synthesis of transforming fermentative system (Horvath,
Alexander, 1970; 197Oa). For instance, Horvath and Alexander gave as an
example of cometabolism the discription of transformation of m-chlorobenzoic
75
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acid in 4-chlorcatechol by cell Arthrobacter sp.grown en the medium with
benzole acid. In this case the substrate was oxidised more intensively and
without lag-phase. (Horvath, Alexander, 197O).
We consider conetabolism to be the processes of fermentative conversion
of organic compounds which are carried out by microorganisms only in
conjugation with the use of additional substrates. Cometabolism reaction of
some substrate exhibits itself only in the presence of oosubstrate of certain
structure and in case it is metabolised. Close interrelation between meta-
bolism of the two substrates/ dependence of cometabolism process on the
nature of oosubstrate are/ in our qppinion/ the characteristic and distinctive
features of cometabolism/ representing biological specificity of this
phenomenon. The best known are the cometabolism processes of foreign compounds-
xenobiotics, though there are also the example* of cometabolism of natural
compounds for instance steroids and terpenes as well as such substrates as
xylose, widely spread in nature and easily metabolized (Yoshitake et al.,
1971).
Our investigations prove that conversions of many xenobiotics are
possible only under ccmetabolisiroonditions.
Nowadays the following reactions carried out under the cometabolism
conditions are described.
1) Oxidation of methyl groups of n-alkanes (Leadbetter, Poster, 196O);
2) Oxidation of methyl groups of aromatic and heterocyclic compounds
(Raymond et al., 1976;Skryabin/ Golovleva, 1976).
3) Oxidation of cycloalkanes (Ooyama, Foster, 1965).
4) Hydroxilation of aromatic ring/ hydroxilation of steroids (Vesina
et al., 1969);
76
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5) Acetylation of aminogroups (Golovleva et al., 1975);
6) Co-reduction (Nona et al., 1973; 1974);
7) Cyclization of aliphatic radical (Skryabin et al., 1974),
Partial and full degradation of such recalcitrant pesticides as 2,3,6-TBA,
2,4,5-T acid, DDT has been described. In our laboratory we have completely
decomposed herbicides alvison-8 and ordrame under cometabolism conditions.
The latter is resistant herbicide and until recently there was no data about
its degradation.
Consequently, both the processes of xenobiotic transformation and their
full degradation can occur under the cometabolism conditions.
Let us consider in detail the types of cometabolism reactions. The
culture Nocardia corallina I A transformed isomeric xylenes, substituted
toluenes, alkylpyridines, cresols only in the process of growth on the
variety of additional substrates fig 1 .Degradation of alvison-8 also took
place during the growth of this culture on the medium with octane or glucose
fig.2. Degradation of herbicide ordram was also carried out under the growth
of Bacillus sp.21 on the medium with ethanol fig.3.
At the same time there exist processes which take place not during the
groafch but in the process of cosubstrate metabolism.
Oxidation of p-xylene and 3-methylpyridine by Nocardia corallina I A
was performed conjugated with xylose conversion to xylonic acid fig.4. Culture
growth on the medium with xylose was not observed, i.e. in this case
transformation of foreign compound took place together with cosubstrate
transformation.
Degradation of herbicide alvison-8 Pseudomonas diminuta and Pseudomonas
putida was also carried out only in the process of co-substrate metabolism
77
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1 days 2
3-Melhylpyridine oxidation by Nocardia corallina 1A under growth
on glucose
1 -concentr of nicotinic acid J - pH
2-culture growth A- glucose decrease
Fig.1. 3-Methylpyridine oxidation by Nocardia coralline 1A under growth on
glucose.
1 - concentr. of nicotinic acid, 2 - culture growth, 3-pH,
4- glucose decreojse.
78
-------
10
iZ
7
6
5
eo
.22 2
days
Fig.2. Growth of Nocardia ooroilina {-) and PseudoiDnas aeruginosa B-12 (—)
on glucose 1. Decrease of alviaon -8-2.
79
-------
decrease of ordram, growth
glucose ; x-ethanol ; A-xylose
Fig. 3. Qrdram degradation by Bacillus sp 21R under growth on different
substrates.
- decrease of ordram, growth, o - glucose, x - ethanol,
- xylose.
so
-------
Cxytee
I \. 2 y<- 200
Cnic
mg/l
300
100
5 6 days
Ficj.4» Transformation of 3-methylpyridine by Nocardia oorallina 1A conjugated
with xylose transformation.
1 - xylose concentration; 2 - nicotinic acid concentration,
3 - optical density.
81
-------
fig.5. None of the active oosubstrates served as a growth substrate for these
cultures even after the addition of growth factors though all of them were
actively oxidized by washed cells in Varburg apparatus.
It should be noted that even alvison degradation was carried out in the
process of growth (for example, under growth on glucose for the culture
Nocardia corallina) the intensity of growth and degradation was characterised
by the inverse proportion. As a rule, maximal specific rate of growth did not
coinside with the maximal rate of herbicide degradation fig 2 .
11
10
9
I 8
i 7
6
E 5
op 4
§ 3i
•S 2
•3 1
1 2 5
-------
The analysis of the presented data allows to assure that the mechanisms
of co-oxidation of different substrates by various cultures differ in seme
characteristic details each other. These mechanisms depend, in part, on the
abbility of microorganisms to metabolise various carbon compounds and to use
than as ajgrowth substrate as well as, probably, on the specifities of cata-
bolism of co-substrates with different structure. However there can be
noticed a general principle of cometabolism processes - the processes of
degradation carried out under the co-oxidation conditions are the most
effective in the presence of co-substrates which are intensively metabolized
but are unable to maintain intensive growth of microorganisms. Consequently
it is possible to speak about four types of cometabolismsI
1) transformation of foreign compound in the process of microorganism
growth on the expense of co-substrate;
2) xenobiotic transformation under the co-substrate transformation; in
this case the co-substrate is not the source of carbon;
3) degradation of the main substrate under the microbial growth at the
expense of co-substrate;
4) xenobiotic degradation under the co-substrate transformation.
In spite of the obvious and very close dependence of the main substrate
transformation on the nature of co-substrate the character of this relation
is not cleryfied yet. As I have already mentioned above, our experiments with
introduction of microorganisms into natural water reservoires did not give
positive results.
However/ the degradation of herbicides was significantly accelerated
after infreducing of co-substrates. So, analysis of 2.4-D dynamics in waste
waters of rice fields has shown that 2.4-D disappeared more quickly if
83
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propionate was used as co-substrate. In this case the herbicide was not
detected in the water in 3 days, at the same time about 25% of initial 2.4-D
was present in control experiments (without propionate) fig.6.
Similar results were obtained in experiments of this year in Moscow
region with ordram degradation. Addition of cosubstrate-ethanol to a water
reservoir accelerated ordram degradation in comparison to control (without
cosubstrate).
The study of ccmetabolism is at the first stage of its development.
There is no doubt that the knowledge of regularities of interrelation between
microorganisms and several substrates is not only practically but also
theoretically important, i.e. the importance of the study of ccmetabolism
as biological phenomenon is beyond doubt.
1
3 4
6 days
Fig.6. Ccmetabolism 2.4-D with (-) and without ( ) propionate.
84
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LITERATURE
Horvath R. 1972. Bact.Rev. 36, 146.
Horvath R., Alexander M. 1970. Canad.J.Microbiol., 16, 1131.
Horvath R., Alexander M. 1970 a. Appl.Microbiol., 20, 254.
yoshitake Y., H.Ohiwa, M.Shimaraura, T.Iitai, 1971. Agric.Biolog.Chem., 3_5, 905.
Leadbetter R.R., Foster J.W. 1960. Appl.Microib., 35, 92.
Raymond R.L., V.W,Jatnison, J.O.Hudson. 1967. Appl.Microbiol., 15, 357.
OOyama J.S., Poster J.W. 1965. Antonie van Leeuwenhoek J.Microb.and serol.,31,45.
Vezina C., S.N. Sehgal, K.Singh. 1963. Appl.Microbiol., V[, 50.
Golovleva L.A., Solov'eva T.F., Skryabin G.K. 1975. Proceedings of the first
Intersect.Congress of IAMS, 2, 557.
Y., Tatsumi C. 1973. J.Chem.Agr.Soc.Japan., 47, 705.
Y., Tatsumi C., ^bna^ura S., H.Ueda, 1974, Agric.Biol.Chem., 38, 735.
85
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ON THE ESTIMATION OP THE ANTHROPOGENIC POLLUTION EFFECT
ON THE FUNCTIONAL STATE OF THE SOIL MICROFLORA
E. I. Gaponyuk, V, A. Kobzev
Institute of Experimental Meteorology, Obninsk
The biosphere is the ecological system in which a variety of
organisms and their associations are in a definite interaction
with the environment. Ever-increasing anthropogenic activity re-
sults in the accumulation in the biosphere of stable compounds
which can significantly change the living conditions and, conse-
quently, the reactions determining interactions between organisms
and the environment.
Among all the geophysical media, soil is subjected to the
greatest anthropogenic action and is the most dangerous link in
the circulation of industrial and agricultural toxic materials.
Microorganisms play a leading part in the biogenic migration and
transformation of organic and mineral substances in soil. Bio-
transformation accomplished by the soil microflora involves a
great quantity of chemical elements amounting to millions and
billions of tons. The number and amount of substances involved
in bi©transformation and biogenic migration increase with the
86
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development of industry and the increase in application of che-
micals in agriculture.
The interaction of microorganisms with foreign for the bio-
sphere substances is intensively investigated, mainly relative
to the ability of microorganisms to decompose synthetic compo-
unds. As for the effect of industrial and agricultural toxic ma-
terials upon the soil micro-flora, it is investigated very poorly.
Data on this problem available in literature are very contradic-
tory.
Due to the fact that the soil cover together with its micro-
world plays a role of the universal biotransformer of organic and
mineral substances, and that the accumulation of toxicants in soil
presents danger for the vital activity of the soil microflora and
•transformation processes fulfilled by it, there arose a problem
of assessing and forecasting the state of soil which is one of the
main components of the ecosystem.
The integral index of the soil state is its biological activi-
ty [l] • Tne biological activity of soil is a concept reflecting
the whole complex of biotransformation processes taking place in
goil« One of ^e main indexes of the biological activity of soil
the enzymic activity |_2, 3, 4-J. There are many enzymes initi-
*ne Di0transforma'tiori processes in soil. However, not all of
them can be used for the assessment of the functional state of mic-
roorganisms because their role in the processes of the vital acti-
* cei;Ls is different.
87
-------
An essential manifestation of the vital activity is metabolism
that is^ a complex of processes directed to the reproduction of Hi
ving substance. The energy required for this is released by the
oxidation-reduction processes. Enzymic systems catalyzing the trans-
port of electrons are very complicated and act as highly organized
complexes.
Oxidoreductases are very numerous, but not a single full biolo»
gical oxidation process occurs without participation of dehydroee-
nases [5], A universal role of dehydrogenases in the biotransforma-
tion processes accomplished by living cells is explained by their
ability to induce the transport of electrons both under aerobic
and anaerobic conditions using various organic and mineral compo-
nents of soil as an acceptor of hydrogen [e]. Thus, co-oxidatio
is one of the most important manifestations of the vital activity
of microorganisms in which dehydrogenases play an essential role.
Investigation of a number of indexes of the biological activity
of soils shows a good correlation of the dehydrogenase activity
with the proteolytic, nitrifying, respiratory activity and absorp*
tion of oxygen by soil J_7|8J.
According to data obtained by many authors, the dehydrogenase
activity depends on all the ecological factors in soil which deter-
mine the quantitative and qualitative composition of the soil mic—
roflora and reflect the level of its vital activity and the inten-
sity of biotransforraation processes in soil [9J.
Data obtained by many authors show that the dehydrogenase ac-
tivity presents a sensitive index of the total susceptibility of
88
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the microflora of soils and active silts to chemical substances
toxic for main reactions of metabolism | 10, II, 12, IjJ.
Based on all the said above, the dehydrogenase activity was
chosen by us as a criterion for evaluating the effect of industrial
and agricultural toxicants on the biological activity of the soil
microflora.
To determine the dehydrogenase activity soil samples were taken
from model experiments carried out in various types of soil in ag-
ricultural and industrial regions. The soil samples had various re-
sidues of the sum of oC» ft"-hexachlorocyclohexane, DDT and its meta-
bolites and various amounts of the sum of heavy metals: lead, chro-
miuni nickel, vanadium, copper. The dehydrogenase activity was de-
termined in air-dried soil samples by the photocolorimetric method
from the amount of formazan formed by the reduction of triphenyl-
tetrazolium using Lenhard's method modified by Ross. The results
of the dehydrogenase activity determination were expressed as mic-
roliters of hydrogen, knowing that the formation of I mg of forma-
zan requires 150*35 microliters of hydrogen. Analysis of the con-
tents of 0^, 0-hexachlorocyclohexane, DDT and its metabolites in
soil samples was made by the gas-liquid chromatography technique.
Analysis of the contents of heavy metals in soil samples was made
by the spectral method.
All the analyzed soil samples without addition of exogenous
substrates and coenzymes were characterized by the dehydrogenase
activity. When investigating the dehydrogenase activity depending
on the incubation time, the short-period stable auto-oscillations
89
-------
of activity were found under invariable experimental conditions
(Fig. I).
Methods for the dehydrogenase activity determination based
upon one definite period of soil sample incubation give the state
of microflora only during this period of time but do not charac-
terize its general functional state. Thus, for example, determi-
nations of the dehydrogenase activity in soils with relatively
large and small residues of chloroorganic pesticides carried out
by the above methods either do not show any difference in the mic-
roflora activity (Fig. la, c, d) or give contradictory results
(Pig. I b) for the first 24 hours of incubation. And only longer
observations reveal that the functional activity of the microflo-
ra in soils with high contents of toxicants is lower than that in
a relatively clean samples.
Talcing into account auto-oscillations of the dehydrogenase ac-
tivity and contradictions of its single measurements, we think
that it is reasonable to evaluate the biological activity of the
soil microflora from the dynamics of the dehydration process.
The short-period autooscillations of the dehydrogenase acti-
vity found by us were of a methodical value. Due to this, we began
to estimate the state of microflora from the data of the dehydro-
genase activity observations averaged over 10 days.
Investigations of the dynamics of the dehydration process in
soils of agricultural regions with various residues of chlororga-
nic pesticides show that the average level of the dehydrogenase
activity in soils with large contents of toxicants is lower than
90
-------
1 2 3
56789
Days
_ or-
J I
10
I I
J I
3VT5 6 78 9 10
Days
234 56789
Days
23456789 10
Days
Pig. !• Change of the dehydrogenase activity of the microflora
in soils having various residues of pesticides (the sum
of DDT and its metabolites, C^.- and jf-hexachlorocyclo-
hexane) depending on the incubation time.
-o - soils with relatively low residue of pesticides;
-o - soils with relatively high residue of pesticides.
91
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that in the control samples with smaller residues of pesticides
(Table I).
The response of microflora to industrial contaminants (Pb
Or, V, Cu) is that large contents of these chemical elements in
soil (2760 mg/kg) as well as small contents (115 mg/kg) diminish
Table I. Change of the dehydrogenase activity of soils de-
pending on the residues of chlororganic pesticides
(DDT and its metabolites, ck— and X^— hexachloro—
cyclohexane)
Soils t
i
t
s
Sierozem
Ordinary
chernozem
Calcareous
chernozem
Residues of
the sum of
DDT and its
metabolites
(jUS/kg)
22403
627
1964
54
1081
52
: Residues of
: the sum of
: cC-BHC and
* (ju g/kg)
327
12
—
-
6
5
: Dehydrogenase
: activity
: (jul H2/Ig soil)
: (14 - m)
*
25.0 i 5.4
49.3 i 9.8
27.1 i 9.4
52.0 t 13.7
3.1 - 0.3
II.6 ± 2.6
92
-------
the dehydrogenase activity (Table 2). And only in a definite con-
centration range (162-586 mg/kg) the dehydration processes are in-
tensive.
The toxic effect of high concentrations of heavy metals in
soils of industrial regions is greater than that of pesticides.
Decrease in the dehydrogenase activity in soils with high con-
tents of toxicants may be one of the reasons of decreasing the
rates of their biotransformation and this results in increase of
the time periods of their toxic effect. We made an attempt to as-
sess the toxicity of soils with high contents of toxicants and
low dehydrogenase activity from the germination of clover and bar-
Table 2. Change of the dehydrogenase activity of soils
depending on the contents of the sum of heavy
metals (Fb, Ni, Cr, V, Cu)
The sum of heavy metals Dehydrogenase activity
(mg/kg) (jul H2/I g soil)
(M ± m)
2760 3.5 ± 0.3
586 25.4 - 3.1
162 33.2 ±4.6
115 3.4 ± 0.4
-------
ley seeds. The germination of clover and barley seeds (during
15 days at temperatures of 20-25°C and 60$ of total moisture ca-
pacity) was the better, the higher was the dehydrogenase activity.
In soils with the dehydrogenase activity of about unity, the ger-
60
54
48
o 42
in
bo 36
c* 30
Q
18
12
6
o
I
O
.._-0 0--
456
Days
8
10
Pig. 2. Change of the dehydrogenase activity of the microflora
in soils with various contents of heavy metals (R>t
V, Ni, Cu) depending on the incubation time.
o o - total amount of metals (162 mg/kg)
o— « —o - total amount of metals (586 mg/kg)
o o - total amount of metals (2760 mg/kg)
94
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mination of seeds either did not occur at all or was retarded.
Recognizing the similarity between the action of toxicants on
the living cell one should recognize the similarity between mecha-
nisms of their action as well.
The data presented in this paper indicate that the toxic ef-
fect of chlororganic pesticides on the soil microflora may be ac-
counted for by the disturbance of the dehydration processes which
are of energetical value for the cell. And the decrease in the de-
hydrogenase activity may lead to a decrease in the bi©transforma-
tion processes associated with it.
Further investigation of the chosen criterion seems to us per-
spective not only in the practical aspect but also in the theore-
tical one.
References
I. Alekwandrova T. S., Shmurova E. M. The enzymic activity of
soils. Itogi nauki i tekhniki. Seriya pochvovedeniye i agro-
khimiya, v. I, p.p. 5-69, Moscow, VINITI, 1974.
2. Galstyan A. Sh. On the evaluation of the degree of soil ferti-
lity from enzymic reactions. In: "Microorganisms in agricul-
ture", Moscow, Moscow University, 1963.
5. Konovalova A. S. The enzymic activity as a diagnostic index for
virgin and cultivated soddy podzolic soils. "Pochvovedeniye'1,
No. 7, P.P. 29-36, 1970.
95
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4. Mashtakov S. M., Kulakovskaya T. N., Goldina S. M. The activity
of enzymes and the intensity of respiration as an index of the
biological activity of soils. Doklady Akademii Nauk SSSR, v. 98
No. I, p.p. I4I-I44, 1954.
5. Peterson N. V., Kurylyak E. N. Investigation of initial stages
of the organic matter transformation in soils by determining
the dehydrogenase activity of microflora in soil samples. In:
"Microbiological and biochemical methods for investigation of
soils", Kiev, "Urozhai", p.p. I2I-I24-, 1971.
6* Lenhard G. Die Dehydrogenaseactivitat des Bodens, als Map ftfr
Microorganisementatigkeit im Boden. "Zeitschrift fttr Pflanzenexw
nahrung, Dungung, Bodenkunde", Bd. 73 (118)f H. I, I-II, 1955.
7, Skujins J. Dehydrogenase: an indicator of biological activities
in arid soils, Bulletin from the Ecological Research Committee
Stockholm, v. 17, p.p. 255-24-1, 1975.
8, Stevenson I. L. Dehydrogenase activity in soils. "Canadian Jour-
nal of Microbiology", v. 5, No. 2, p.p. 229-235, 1959.
9. Schaefer R. L'activite dehydrogenasique comme mesure de I'acti-
vlte' biologique globale des sols. "Annales de 1'Institut Pas-
teur", Pari*, 105, No. 2, p.p. 212-217, I%3.
10. Vyglazova E. G., Borovikova T. I., Chernysh G. P. Optimization
of the cleaning of sewage waters from the vitamin industry
using microorganisms. In: "Microbiological methods for the
environment contamination control". Collection of abstracts,
Puschino, p.p. 20-21, 1975.
96
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II* Bershin G. N. The effect of chemicals upon bacterial cells*
Moscow, Medgiz, 1952.
12, Bespamyatnov G. P., Bogushevskaya K. K. et al. Maximum per-
missible levels of toxicants in air and water. Leningrad,
"Khimiya", 1972.
* Casida J. E., Klein D. A,, Santoro Th. Soil dehydrogenase ac-
tivity. "Soil Science", v. 98, No. 6, p.p. 37I-376| 1964.
97
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TRANSFORMATION AND TRANSPORT PROCESSES IN AQUATIC SYSTEMS
George L. Baughman
Environmental Research Laboratory
U. S. Environmental Protection Agency
College Station Road
Athens, Georgia 30601, USA
Dynamics of transformation and transport are described in
terms of their controlling environmental parameters. Recent
advances in our ability to mathematically describe the rate and
extent of microbiological, chemical, and physical processes are
discussed and data are presented to illustrate interrelation-
ships between these processes.
Microbiological rates have generally been modeled using
Monod kinetics. This kinetic model (1) is described and the
effect of isolation and high substrate concentration on the
growth constants demonstrated (2). When substrate concentra-
tions are low as in the case of insoluble compounds like many
pesticides, the Monod expression reduces to second-order rate
expression (3,4). Studies of malathion degradation by bacteria
gave results that agreed within a factor of two when the second-
order rate constant was measured directly or calculated from
Monod constants. More recent studies (5,6) have compared data
from chemostats, flasks, and a simulated stream system which
incorporate both chemical and microbial degradation.
Partitioning of stable insoluble pesticides between water
and microorganisms has recently been given greater attention.
In most cases this phenomenon has been found to be rapid, re-
versible, and adequately described by a Freundlich isotherm or
partition coefficient (3,7,8). However, Sugiura et al. (9)
have reported a two-step process for accumulation of BHC iso-
mers. Some implications of partitioning have been shown by
preferential accumulation in bacteria of the more water insolu-
ble components of toxaphene (10).
Chemical reactions in water can occur by many different
mechanisms, some of which have been described by Wolfe et al.
(11). However, reaction of pesticides with water (hydroTysTs)
is one of the most important chemical transformation mechanisms
in aquatic systems. It has been shown that the pH dependence
98
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of these reaction rates is predictable and that the half-life is
a poor indicator of rate unless reactant concentrations are
specified. Recent detailed kinetic studies on malathion (12)
and cyanazine (13) have quantified the effect of temperature
and pH over a wide range. Malathion studies have demonstrated
the effect that temperature (12) and pathway (3) can have on
transformation products. The use of structure activity rela-
tionships to predict hydrolytic rate constants has been applied
to the case of 2,4-D esters (14) in considering competition
between hydrolysis, photolysis, and volatility.
The effect of a rapid pre-equilibration step on rate pro-
cesses can be described by an equation of the form
- (1)
dt 1 + K[A]
where [P]_ = concentration of total pesticide in the system
K = equilibrium constant (partition coefficient)
k = pseudo-first-order rate constant
[A] = concentration of sorbent (solvent) in the system,
Effects of sediment partitioning on hydrolytic half-life (15)
and volatilization rate are deomonstrated by data on pesticides
and PCBs. Singmaster (16) has also applied eq. 1 to DDT hydro-
lysis in the presence of a partitioning solvent.
Evidence is also presented to support the possible impor-
tance of other chemical reactions as indicated by abiotic meth-
lation of mercury (17), N-nitrosation of atrazine (18), and
degradation of methoxychlor.
Photochemical transformations are described in terms of
three different processes (11,19): direct photolysis, sensi-
tized photolysis, and indirect photolysis. Kinetics of direct
and sensitized pesticide photolysis have been studies for a
number of pesticides in water (11,14,19,20).
Under most environmental conditions the pesticide absorbs
only a small fraction of the light, and the rate law is first-
order in pesticide and a function of light intensity. However,
light intensity in aquatic systems is a function of latitude,
time of day, season, water absorbance, and depth. A recently
completed computer program (19) for direct photolysis rates
couples these properties with the spectrum of the pesticide
and its quantum yield. Data are presented which show the
effect of latitude on photolysis rates of carbaryl and tri-
fluralin. Agreement between computed and observed half-lives
of several pesticides is discussed.
99
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Photolysis rate of parathion in natural waters is approxi-
mately proportional to water absorbance and independent of the
water source. In this case reaction apparently occurs by energy
transfer and paraoxon and P-nitrophenol are the major products.
Physical transport from water to air is a pathway that has
received little attention and its importance for most pollutants
is poorly understood. A method (21) for the reaeration capacity
of streams is suggested as an approach for volatilization of
organics (22). Studies of this type carried out with PCB's in
our laboratory are presented. Another technique based on
Henry's law and average volatilization rates (23,24) of water
has been applied to DDT (16), 2,4-D esters (14), and a number
of other organic compounds (25).
REFERENCES
1. Stumm-Zollinger, E., and R. H. Harris. Chapter 23. in;
Organic Compounds in Aquatic Environments, Faust, S. P~7, and
J. V. Hunter (eds.), Mercell Dekker, Inc., New York. 1971.
2. Jannosch, H. W. Growth Characteristics of Heterotrophic
Bacteria in Seawater. J. Bacterial. £5:722 (1968).
3. Paris, D. F., D. L. Lewis, J. T. Barnett, and G. L. Baugh-
man. Microbial Degradation and Accumulation of Pesticides
in Aquatic Systems. U.S. Environmental Protection Agency
Research Report. #EPA-660/3-75-007. 1975.
4. Paris, D. F., D. L. Lewis, and N. L. Wolfe. Rates of
Degradation of Malathion by Bacteria Isolated from Aquatic
Systems. Environ. Sci. Tech. 9_:135-138 (1975) .
5. Falco, J. W., D. L. Brockway, K. L. Sampson, H. P. Kollig,
and J. R. Maudsley. Models for Transport and Transforma-
tion of Malathion in Aquatic Systems. In: The Proceedings
of the American Institute for BiologicaI~~Sciences Symposium.
Freshwater Quality Criteria Research of the Environmental
Protection Agency, Corvallis. 1975 (In press).
6. Falco, J. W., K. L. Sampson, and R. F. Carsel. Physical
Modeling of Pesticide Degradation. Developments in
Industrial Microbiology. (In press).
7. Grimes, D. J., and S. M. Morrison. Bacterial Bioconcentra-
tion of Chlorinated Hydrocarbon Insecticides from Aqueous
Systems. Microbiol. Ecology. 2_:43-59 (1975).
100
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8. Neudorf, S., and M. A. Q. Khan. Pick-up and Metabolism of
DDT, Dieldrin, and Photodieldrin by a Fresh Water Alga
(Ankistrodesmus amolloides) and a Microcrustacean (Daphnia
polex) « Bull. Environ. Contain. Toxic. 1.3_: 443-450 (1975) .
9. Sugiura, K. / S. Sato, and Miki Gato. Adsorption-Diffusion
Mechanism of BHC-Residues. A Consideration Based on Bac-
teria Experiments as Models. Chemosphere. 3_: 189-194
(1975).
10. Paris, D. P., D. L. Lewis, and J. T. Barnett. Bioconcentra-
tion of Toxaphene by Microorganisms. Bull. Environ. Contam.
Toxic. (In press) .
11. Wolfe, N. L., R. G. Zepp, G. L. Baughman , R. C. Fincher, and
J. A. Gordon. Chemical and Photochemical Transformation of
Selected Pesticides in Aquatic Systems. U.S. Environmental
Protection Agency Research Report #EPA-600/3-76-067 (1976) .
12. Wolfe, N. L., R. G. Zepp, J. A. Gordon, G. L. Baughman, and
D. M. Cline. The Kinetics of Chemical Degradation of Mala-
thion in Water. Environ. Sci. Tech. (In press) .
13. Brown, N. P. H., C. G. L. Furmidge, and B. T. Gray son.
Hydrolysis of the Triazine Herbicide, Cyanazine. Pestic.
Sci. :669~678
14. Zepp, R. G., N. L. Wolfe, J. A. Gordon, and G. L. Baughman.
Dynamics of 2,4-D Esters in Surface Waters: Hydrolysis,
Photolysis, and Vaporization. Environ. Sci. Tech. 9:1144-
1150 (1975).
15. Wolfe, N. L., R. G. Zepp, D. F. Paris, R. C. Hollis, and
G. L. Baughman. Methoxychlor and DDT Degradation in Water:
Rates and Products. (In press) .
16. Singmaster, J. A. Environmental Behavior of Hydrophobia
Pollutants in Aqueous Solutions. M.S. Thesis. University
Microfilm, Ann Arbor, Mich.
17. Rodger s, R. D. Methylation of Mercury by a Sodium Hydrox-
ide Extract of Soil. (In press) .
18. Wolfe, N. L., R. G. Zepp, J. A. Gordon, and R. C. Fincher.
N-Nitrosamine Formation from Atrazine. Bull. Environ.
Contamin. Toxic. 5_:342-346 (1976).
19. Zepp, R. G., and D. M. Cline. Rates of Direct Photolysis
in the Aquatic Environment. Environ. Sci. Tech. (In
press) .
101
-------
20. Zepp, R. G., N. L. Wolfe, and J. A. Gordon. Photodecomposi-
tion of Phenylmercury Compounds in Sunlight. Chemosphere.
^:93-99 (1973).
21. Tsivoglou, E. C. Tracer Measurements of Stream Reaeration.
Federal Water Pollution Control Administration. U. s.
Department of the Interior, Washington, DC. June 1967.
22. Hill, J. IV, H. P. Kollig, D. F. Paris, N. L. Wolfe, and
R. G. Zepp. Dynamic Behavior of Vinyl Chloride in Aquatic
Ecosystems. U.S. Environmental Protection Agency Research
Report. #EPA-600/3-76-001. 1976.
23. Mackay, D., and A. W. Wolkoff. Rates of Evaporation of Low-
Solubility Contaminants from Water Bodies to Atmosphere.
Environ. Sci. Tech. 7_:611-614 (1973).
24. Mackay, D., and P. J. Leinonen. Rates of Evaporation of
Low-Solubility Contaminants from Water Bodies to Atmosphere.
Environ. Sci. Tech. 9_:1178-1180 (1975).
25. Dilling, W. L., N. B. Tefertiller, and G. J. Kallos. Evapor-
ation Rates and Reactivities of Methylen Chloride, Chloro-
form, 1/1,1-Trichloroethane, Trichloroethylene, Tetrachloro-
ethylene and other Chlorinated Compounds in Dilute Aqueous
Solutions. Environ. Sci. Tech. 9:833-838 (1975).
102
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ESTIMATION OF ORGANOCHLORINE PESTICIDE LOSS IN SURFACE
RUNOFF WATERS
Ts. I, Bobovnikova, E. P. Virchenko, G. K. Morozova,
Z. A. Sinitsyna, Yu. P. Cherkhanov
Institute of Experimental Meteorology, Obninsk
Institute of Applied Geophysics, Moscow
Pesticide migration in water is one of the major pathways of
their transport in the environment.
Surface runoff water which occurs at the watershed as the re-
sult of snowmelt or rainfall causes pesticide removal from the wa-
tershed area (agricultural lands and forests) and their entering
rivers and basins.
Investigations showed that surface runoff from the watershed
was the major source of river water polution with pesticides.
In spring the channeled runoff of the most plain rivers of the
Soviet Union is formed mainly by snowmelt waters from the water-
shed. It is over this period that one should expect the most pes-
ticide removal from the watershed area and their entering river
channels.
It is necessary to quantify pesticide loss in surface runoff
waters from the watershed both when considering pesticide transport
103
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in the environment as a whole and when predicting surface water
pollution with pesticides.
The amount of pesticides entering the river network in surface
runoff waters from the watershed depends on a number of factors,
the major factors being pesticide solubility in water and condi-
tions of water runoff from the watershed. It should be noted that
according to the works by Nicholson [ij , the amount of pesticides
in runoff waters is affected by the time interval between the pes-
ticide application and the first surface runoff.
We investigated the loss of organochlorine pesticides - DDT
and y -BHC in surface runoff waters over the period of spring flood
and rainfall.
Pesticide loss in runoff waters in spring was studied at the
natural river watersheds where pesticides had not been applied in
the previous 5 years and at the experimental runoff plots when si-
mulating pesticide fallout on the snow cover as well as the loss
of pesticide residual amounts in runoff waters from these plots.
Pesticide loss in rain runoff waters due to the natural summer
precipitation was studied at the experimental runoff plots installed
at the natural river watershed.
Pesticide loss in surface runoff waters from the watershed was
characterized quantitatively by the loss coefficient which was de-
termined from the formula:
u
f s
104
-------
where u is the amount of pesticides lost from the watershed (run-
off plot);
Nj is the amount of pesticides at the watershed (0-20 cm soil
layer);
Np is the amount of pesticides in the watershed snow cover
before the snowmelt - in spring;
or the amount of pesticides deposited with rain - in sum-
mer.
Pesticide loss in runoff waters over the period of spring flood
was investigated at two watersheds in the Moskva-river basin: in
its upper course and in one of its tributary. The first watershed
p
area was 5000 km , two thirds of this area being regulated by the
o
storage reservoirs, and the second one was 800 km . In spring the
formation of river runoff at the first watershed occurs mainly due
to snowmelt waters from the non-regulated part of the watershed.
This fact was taken into account in the further calculations.
Water samples were collected every day at the terminal obser-
vation point of a given watershed and required hydrological obser-
vations were carried out. Using the data obtained we calculated the
amount of pesticides (u) lost from the watershed over the period
of spring flood. The amount of pesticides in the watershed soils
(NT) was determined by collecting soil samples (0-20 cm layer) with
regard to their properties and species of crops at the agricultural
lands. The amount; of pesticides in the watershed snow cover (Np)
was calculated from the results of snow survey and determination
105
-------
of pesticide content in snow samples collected over the whole depth
of snow cover.
The coefficients of pesticide loss in surface runoff waters
calculated from the above formula were 0.060S and 0.0926 at the first
watershed and 0.395 and 0.1% at the second one for DDT and T-BHC,
respectively.
These results were obtained at the DDT and $" -BHC contents in
soils from 5 to 60 ^g/kg and from 0.8 to 4 jug/kg, respectively,
and at the DDT and ^-BHC concentrations in water from 0.03 to
Apart from investigations at the river watersheds, we studied
the ^-BHC loss in runoff waters at the experimental runoff plot
the snow cover of which was treated with T-BHC before the snowmelt
and at the similar untreated (background) plot (20 m x 5 m in size
each). The coefficient of ^-BHC loss from the treated plot was 3.?%
and from the untreated one - 0.2^. The depth of water runoff at
these plots was approximately 2,5 times greater than that from the
watersheds considered above.
Analysis of the DDT and ^-BHC loss coefficients obtained in
spring showed that first, the loss coefficient value was directly
proportional to the depth of water runoff, and second, the loss
coefficient of Just applied df-BHG was an order higher than that
of its residual amounts.
Special runoff plots were installed to investigate pesticide
p
loss in runoff waters due to rainfall, 6 m each. We determined the
amounts of pesticides deposited with rain and lost in surface water
106
-------
runoff due to a given rain as well as the pesticide content in soil,
The maximum loss coefficient obtained at the 25,4 mm precipitation
was 2.5 x lO"2^ for
-------
HEXA3HLOROCYCLOHE3LANE, METARHOS, JWD GHLOfiOifiOS JM3OIPOS£DIQN
IS SOIL JWD 'JDHEIfi MIGRATION WITH TH2 ffJfffirJS OJ1 SURFAJE
by Tarasov M»N«, Korotova L»G«, Demchenko A»S«, Brazhnikova L.7.
tfydrochemic al Institutet Novocherkassk
Great quantities of chemicals and among them pesticides enter
the biosphere due to intensive chemicalization of agriculture. Upon
the influence of different factors the greater part of pesticides
is decomposed in soil forming primary products and certain prepara-
tions are preserved in soil for a long time due to high persistency,
Systematic usage of persistent pesticides and those with high cumu-
lative properties at vast watersheds occupied by agricultural lands
may result in pollution of natural waters*
la ord>r to t>redict pollution, of natural bodies by Pesticides,
it is necessary to «tudy the rate of their decomposition in differ-
ent soils, migration capability as well as to obtain quantitative
characteristics of their removal from Agricultural lands.
•
Studies of hexachlorocyclohexane (BHC), metaphos, and chloro-
phos decomposition in soil, their migration capability PS well as
*he Dosflibility of washing out by su-r-face runoff were carried out
»t four runoff plots with the area 100 sq»m located in ^he zone of
drought steppe.
108
-------
The soil at the runoff plots was chestnut, semiloamy contain-
ing 3.8^ of humus; ph was 7.45* The plots were treated with BHG and
metaphos twice - in June, 1972 and 1973« while by ehlorophos only
in June, 1973-
In 1972 BHC was applied at the plots I and 2 at the rate of
120 g Per each plot, v/hile st the plots 3 and 4 metaphos was appli-
ed at the rate of 25 6 Per each plot. In 1973 the first plot was
treated again by BHC -3t the same rate, the third plot was treated
by metaphos twice - in June, 10 and 30 at the rate of 52.5 g. The
fourth plot ?/as plso treated by ehlorophos twice at the rate of
120 g and 300 g3 respectively.
4fc the beginning of the experiment samples were taken every-
day with gradual increase of the interval between sampling up to
5-10-30 days* Soil samples were taken at 3-5 points from the
depth of 0-5, 5-10, 10-20, 20-30, 30-40 and 40-50 cm. "tfater samples
were taken at the outlet of the runoff plots from I to 3 samples
for the period of each rain flood*
Pesticides were determined by thin-layer chromatography.
Decomposition rate of pesticides in soil was not uniform and
depended on meteorological conditions of the year. Dry 1972 was
characterized by high temperature of air and soil surface in summer
period. Average monthly temperature of air in June was 24 C, in July
26°G» maximum temperature was 4-0 C. Average temperature of soil at
this period was 3l°C, end maximum temperature was 65°C. Small pre-
cipitation (several rains in June with total sum of precipitation
47 mm, and in July 9 mm) resulted in the absence of runoff for this
109
-------
period. Therefore in 1972 it was possible to study only the process
of pesticide decomposition in soii.
1973 T-'ras more humid as compared to 1972. The temperature of air
and soil surface was lower. Arerage monthly temperature of air in
June was I9°0. in July - 2l°G, maximum - 29°C. Average monthly
temperature of soil was 24-°C. Frequent and abundant rains (sum of
precipitation in June was 109 mm, in July - 60 mm) were followed
by short-term runoff from the plots.
In dry 1972 decomposition of BHC in soil proceeded slowly
enough. In 10 days after treatment in the soil 80% of BHC were
found, whereas in 20 days - 65%. The period of semidisappearance
was 50 days. In about 1.5 years the BHC content decreased by 99%.
Residues of the preparation (I - J^g/IOO g) were found in the
soil in 2ycars after the treatment (Fig. IA, Table I).
Table I
Persistency of Pesticides in Soil
t
Pesticides!
t
_ f —
."HO
Met aphos
Shlorophos
DOVP
Year
197?
1973
T972
1973
1972
197*
1972
1973
» Period of semidis- !
j appearence, days |
50
2
3.5
I. 3-1.8
-
0.6-0.8
—
I.4-I.5
Period for 99?5
dis appearence, day;
500
40
17
8-13
—
8-10
-
10-14
110
-------
"t i >y i v i M i »«i V" i i» i x i m
IO73
PHC, pg/too
300
200
100
B
Vff [ VH|
R< I »» i | ti I m | Mf I y \
Fig
months
e in nexachlorocycxohexo^ie conteut j.n the upper
5 cm layer of soil.
A - Treatment in June, I>, I?f2
B - Treatment j.n Juiie, IO, 1973
ill
-------
Metaphos was decomposed much faster. In about 3.5 days the
metaphos content in the soil half decreased. Disappearance of the
preparation by 99# was observed on the I?th day, whereas the entire
disappearance was on the 20th day (Fig. 2A).
In the humid year the period of semidisappearance of BHC de-
creased up to 2 days and in 40 days in the soil 1% of the applied
substance was found (Pig. IB). During the year the residual amounts
of the preparation were still found in the soil. The period of
semidisappearance for metaphos was 1.3 - I«8 days. In 8 - 13 days
the pesticide removal was 99^i whereas the entire removal was ob-
served in 10 - 14 days (Fig. 2B).
The highest rate of decomposition v/as observed for chlorophos.
The period of semidisappearance v/as 0.6 - 0.8 days, and entire dis-
appearance was observed in 13 - 15 days. Together with chlorophos
in the soil its metabolite 0.0-dimethyl-0-(2.2-dichlorovinyl)-phos-
phate (DDVP) was found, and its amount on the first day was about
15 -20;% that on the 5th day being 55!% from the sum of toxicants.
2.5 times increase in the treatment rate did not influence the cha-
racter of chlorophos and its metabolite disappearance (Fig. 3).
In dry 1972 all the pesticides studied were localized in the
uoper 5 cm layer. They did not practically migrate to the lower
horizons.
Heavy rains in 1973 during the experiment stimulated pesti-
cide transfer to the depth of the soil. Chlorophos and DDVP were
the most mobile and their concentration in the 5-10 cm layer v/as
55 jig and 25 ju.g/100 sfrespectively; in the 10-20 cm layer - 30 jug
112
-------
ISOO
800
400
10
200
B
Hme
hours)
Fig* 2 " Change in metaphos content in the upper 5 cm layer of
soil*
A- 1972
B - 1973 ~ I - Treatment in June, 10,
2 - Treatment in June, 7?0
113
-------
1300
WOO
300
2000
IS 00
1000
900
Time
10
is (24 kou*&)
B
Fly* 5 -
0 9 '0
Chang6 *n chlorophos conten- and its
in the upper 5 cm layer of soil.
A- Treatment in June, 10, 1973
B - Treatment in June, 30, 1973.
^^ DDVP (2)
114
-------
and 16 jug/ICO g, in the 20-30 cm layer - 16 jug and 12 jug/100 g .
MetaPnos content at the 5-30 cm depth varied from I to 5 jug/100 g.
BHC migrated up to the depth of GO cm. Pesticide concentration in
the soil layer below 10 cm didn't exceed 18 jug/100 g of soil.
Mathematical processing of tne ootained data according to
i.choice,
the program of approximating equatioxIsTsEowed that decomposition of
the investigated pesticides in the soxi is givea oy the
*>
et + d
where C - concentration of preparation;
t - -cime
a»u,e,d - coefficients.
(I)
/ values for dry and. humid year differ by many
times*
£*or exampj.et tne equatio^ for metaphos decomposition under
the dr,y year xs given oy:
' (-O.OOOy)-t + (-0.0021)
for the humid year
(-0.0022)*Ti + (-0.0001)
Study of pesticide removal oy surface runoff from the eXPeri-
JL runoff piots showed that its value is proportioned directly
to tae quantity of applied pesticide and runoff volume and In-
115
-------
to tue period Det;weeu tresciueut; of the fieid aud the
beginning of tJie flow*
Pesticide removal didn't exceed O.UJJS for BHC* 0.04% for
metapnos, a^d 0»^^ for cnxurupnos (together v/itn DDT/P) of the
applied (Tauie 2)»
Taole 2
Pesticide Remova-i- with Surface
^ Pesticide .Removal, from I ha
Pesticide ' ~ #
BHC ^*u 0.03
Metapnos 0.0/-2-55 0.001-0.04
Ghloropnos + DDVP 0.2-67-5 0.002-0.
116
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PARTITIONING AND UPTAKE OP PESTICIDES IN
BIOLOGICAL SYSTEMS
Eugene E. Kenaga
Dow Chemical U.S.A.
Natural bodies of water, blood and plant sap were compared
as aqueous flow systems for transporting pesticides and other
chemicals. The uptake and distribution of pesticides in bio-
logical systems were related to water solubility; volatility
from water; adsorption to soil organic matter, plant and animal
organisms in aquatic ecosystems; effects of temperature; type of
flow system; route of pesticide intake; specific types of organ-
ism tissue; and ratio of biomass to surface area for sorption.
Differences between bioadsorption and bioabsorption were dis-
cussed. Partition coefficients between n-octanol and water;
soil and water; and water and air are important guides to the
bioaccumulation potential of pesticides.
Pesticides, just like other chemicals, are taken up and dis-
tributed in gas, liquid, and solid phases of the environment.
They distribute by flow systems (mainly water or air) to sur-
faces to which they adsorb to and are often absorbed by living
organisms and return changed or unchanged to flow systems inside
or outside of organisms. Three important environmental aqueous
flow systems are bodies of water, blood, and plant sap which,
while variable in flow rate, have the ability to rapidly dis-
tribute solutes and particulates to adsorptive surfaces, organ-
isms, organs, and/or cells. These three transport systems are
composed percentage-wise mainly of water? however, they contain
small amounts of many chemicals with similar functional groups
in common which modify the dominance of water. Because of these
distribution systems, partitioning of pesticides in and from
flow systems can be expected to occur onto surfaces according
to inherent physical and chemical properties of the pesticide
such as volatility, water and fat solubility, and sorption to
Dow Chemical U.S.A., Midland, Michigan 48640
117
-------
solids in the presence of flow systems. Plant and animal or-
ganisms contain and release water, food, and pesticides by par-
titioning them through surfaces, organs, and cell barriers.
Pesticide volatility from water appears to increase with
increasing amounts of water evaporation, and decreasing water
solubility. Thus, even DDT is relatively quite volatile from
water; however, this may be influenced by cosolvents (such as
soil organics) or competitive adsorptive surfaces of soils in
water such as soil particulates or plants or animals.
Sorption of most pesticides, while variable on the mineral
portion of soil, is mainly correlated with the soil organic mat-
ter content which has ingredients having sorptive capacity for
both ionized and unionized, and fat and water-soluble pesti-
cides. The effect of the pH of soil on sorption of acidic and
basic compounds may also be important. Sorption on soil and
organisms takes place most rapidly under the greatest concentra-
tion differential between the flow system and sorptive surface.
Typically well over 50% of the total adsorptive uptake of pesti-
cides occurs in the first few hours of exposure. While the
total amount of pesticide adsorbed on carbon and algae increases
with increasing concentration in the flow system (water), the
concentration factor may decrease with increasing pesticide con-
centration in water. Clearance of pesticides from tissues is
not necessarily at the same rate as uptake, and is often slower.
Other factors affecting adsorption are temperature, speed of
circulation of the flow system, ratio of biomass to flow system
volume, and mode of intake of pesticide into the organism.
The distribution of DDT and other stable chemicals in fat
of animal organisms, if given sufficient time for equilibration,
appears to roughly correlate with the n-octanol:water partition
coefficient obtained as a guide to the~bioconcentration factor
in fat tissues of animals from aqueous sources. This factor
alone can be somewhat difficult to correlate with fat under some
conditions since, in fish, fat is variously distributed in
tissues at different ages, stages of sexual development, and
seasons of the year, sometimes being rather uniformly distribu-
ted and other times not. Also some fat tissues appear to be
more rapidly metabolized than others and, therefore, release
pesticides into the blood at various times of stress or accord-
ing to the need for the fat. The greater the number and volume
of components in an ecosystem, the greater the complexity of the
distribution of the available pesticide from water, and less
likely the expectation of extremes in bioaccumulation. The
distribution of a water and organic soluble compound like
dalapon as indicated by the n-octanol:water partition coeffi-
cient, is in great contrast to DDT, since it does not volatilize
at a rate significantly different from water, nor partition in
favor of animal organisms, or their fat, but does accumulate in
some plant organisms. Herbicides like 2,4-D and 2,4,5-T
118
-------
partition somewhat similarly to dalapon, but when made into an
oil soluble (the butyl ester) form, the octanoltwater partition
coefficient is considerably higher. However, this is not very
significant in nature since the ester bond is not very stable in
animal organisms, and thus the ester does not continue to bio-
accumulate like DDT. Every chemical has a uniqueness in its
combination of physical and chemical properties, and in the way
in which it will act in the environment.
From pesticide bioaccumulation data it is apparent that the
first period of residue pickup is due to adsorption and is often
related to high surface area to mass ratio of the adsorbent and
may result in high residues. With many pesticides no further
significant uptake of residue after the first day is made during
a continued exposure period of days or weeks. However, if the
pesticide is high in fat solubility, low in water solubility
and persistent in the environment, a continued increase in resi-
dues may take place over time until a steady state (equilibrium)
point is reached in live organisms. Such residue pickup is by
absorption and such bioaccumulating chemicals can be detected at
an early stage by obtaining early baseline residue levels for
comparison with later levels. Other very useful partition coef-
ficients to obtain in addition to n-octanol to water are soil
organic matter to water, and water to air. These partition co-
efficients can be calculated roughly from predetermined con-
stants of water and n-octanol solubility and vapor pressure.
These calculated coefficients are useful in determining poten-
tial of pesticides for leaching through soil, and uptake and
distribution throughout the biota. Distribution coefficients
of soil organic matter to water, and of aquatic animal organisms
to water, are often of the same order of magnitude.
BIBLIOGRAPHY
Ahlrichs, J.L. The Soil Environment. Organic Chemicals in the
Soil Environment. Chapter 1. Edited by C.A.I. Goring and J.W.
Hamaker. Vol. 1. Marcel Dekker, Inc., New York (1972).
Altman, P.L. Blood and Other Body Fluids. Biological Handbook.
Fed. Amer. Soc. for Exper. Biology, Washington, D.C. (1961).
Bailey, G.W. and J.L. White. Factors Influencing the Adsorption,
Desorption, and Movement of Pesticides in Soil. Res. Rev.,
32_:29-92 (1970).
Beroza, M., M.N. Inscoe, and M.C. Bowman. Distribution of
Pesticides in Immiscible Binary Solvent Systems for Cleanup and
Identification and Its Application in the Extraction of Pesti-
cides from Milk. Res. Rev., 32:1-61 (1969).
119
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Branson, D.R., G.E. Blau, H.C. Alexander, D.R. Thielen and W.B.
Neely, "Steady-State Bioconcentration Methodology for 2,2',
4,4'-Tetrachlorobiphenyl in Trout." Trans. Am. Fish. Soc.'dn
Press) (1974).
Cope, O.B., E.M. Wook, and G.H. Wallen. Some Chronic Effects of
2,4-D on the Bluegill (Lepomis machrochirus). Trans. Amer
Fish. Soc. 9_9(1):1-12 (1970) .
Cope, O.B., J.P. McCraren, and L. Eller. Effects of Dichloro-
benil on Two Fishpond Environments. Weed Science 17(2):158-165
(1969) . —
Cox, J.L. Uptake, Assimilation, and Loss of DDT Residues by
Euphausia pacifica, A Euphausid Shrimp. Fishery Bulletin,
£0(3):627-633 (1971).
Crosby, D.G. The Photodecomposition of Pesticides in Water.
Fate of Organic Pesticides in the Aquatic Environment, Advances
in Chemistry Series No. 111. American Chemical Society,
Washington, D.C., p. 173-188 (1972).
Crosby, D.G. and R.K. Tucker. Accumulation of DDT by Daphnia
magna, Environ. Sci. & Tech. _5_:714-716 (1971).
Davis, J.C. Estimation of Circulation Time in the Rainbow Trout,
Salmo gairdneri. J. Fish. Res. Board Canada. 27(10);1860-1863
(1970) .
Davis, J.T. and J.S. Hughes. Further Observations on the Tox-
icity of Commercial Herbicides to Bluegill Sunfish. Proc. So.
Weed Conf. 16:337-340 (1963).
Dilling, W.L., N.B. Tefertiller, and G.J. Kallos. Environmental
Fate of Chlorinated Solvent. I. Evaporation Rates and Reactiv-
ities of Methylene Chloride, Chloroform, 1,1,1-Trichloroethane,
Trichloroethylene, Tetrachloroethylene, and Other Chlorinated
Hydrocarbons in Dilute Aqueous Solutions. The Dow Chemical
Company. 30th Annual Fall Scientific Meeting. Midland,
Michigan. Nov. 3 (1973).
Dow Chemical Co., The. Unpublished data. Midland, Michigan
(1974) .
Flint, G.W., J.J. Alexander, and O.P. Funderburk. Vapor Pres-
sures of Low-Volatile Esters of 2,4-D. Weed Sciences 16(1):
541-544 (1968). —
Soring, C.A.I. Physical Aspects of Soil in Relation to the
Action of Soil Fungicides. Annual Review of Phytopathology
5:285-318 (1967).
120
-------
Goring, C.A.I. Agricultural Chemicals in the Environment. A
Quantitative Viewpoint. Chapter 13. Organic Chemicals in the
Soil Environment. Edited by C.A.I. Goring and J.W. Hamaker.
Vol. II. Marcel Dekker Inc., New York (1972).
Goring, C.A.I, and J.W. Hamaker. Organic Chemicals in the Soil
Environment. Vol. I and II. Marcel Dekker Inc., New York
(1972) .
Grzenda, A.R., D.F. Paris, and W.J. Taylor. The Uptake, Metab-
olism and Elimination of Chlorinated Residues by Goldfish
(Carassius auratus) Fed a 14C-DDT Contaminated Diet. Trans.
Amer. Fish. Soc. 2i385-396 (1970).
Gunther, R., W.E. Westlake, and P.S. Jaglan. Reported Solubili-
ties of 738 Pesticides in Water. Res. Rev. 20:1-148 (1968).
Hamaker, J.W. Diffusion and Volatilization. Organic Chemicals
in the Soil Environment. Chapter 5. Edited by C.A.I. Goring
and J.W. Hamaker. Marcel Dekker, Inc., New York (1972).
Hamaker, J.W. and J.M. Thompson. Adsorption. Organic Chemicals
in the Soil Environment. Chapter 2. Edited by C.A.I. Goring
and J.W. Hamaker. Vol. 1. Marcel Dekker, Inc., New York
(1972) .
Hansch, C., A. Leo, and D. Nikaitani. On the Additivity -
Constitutive Character of Partition Coefficients. J. Org.
Chem., 37:3090 (1972).
Hardy, J.L. Effect of TORDON® Herbicides on Aquatic Chain Organ-
isms. Down to Earth, p. 11-13, Fall (1966).
'Hewitt, E.A. Diseases of Poultry. Edited by H.E. Biester and
L.N. Schwarte. Second Edition. Iowa State University, Ames
(1948).
Hughes, J.S. and J.T. Davis. Variations in Toxicity to Bluegill
Sunfish of Phenoxy Herbicides. Weeds 1_1(1): 50-53 (1963).
Isensee, A.R., P.C. Kearney, E.A. Woolson, G.E. Jones and V.P.
Williams. Distribution of Alkyl Arsenicals in Model Ecosystem.
Environ. Sci. & Tech. 7^9):841-845 (1973).
Johnson, B.T. and J.O. Kennedy. Biomagnification of p,p'-DDT
and Methoxychlor by Bacteria. Applied Microbiology 26(1);66-71
(1973).
Johnson, B.T., C.R. Sanders, and H.O. Sanders. Biological
Magnification and Degradation of DDT and Aldrin by Freshwater
Invertebrates. J. Fisheries Research Board of Canada 28(5):
705-709 (1971). ~~
121
-------
Kapoor, I.P., R.L. Metcalf, R.F. Nystrom, and G.K. Sangha.
Comparative Metabolism of Methoxychlor, Methiochlor, and DDT
in Mouse, Insects, and in a Model Ecosystem. J. Agr. Food
Chem. 18(6):1145-1152 (1970).
Kenaga, E.E. An Evaluation of the Use of Sulfur Dioxide in
Fumigant Mixtures for Grain Treatment. J. Econ. Entomol.
£9(6):723-729 (1956).
Kenaga, E.E., W.K. Whitney, J.L. Hardy, and A.E. Doty. Labora-
tory Tests with Dursban Insecticide. J. Econ. Entomol., 58(6)-
1043-1050 (1965) . —
Kenaga, E.E. Guidelines for Environmental Study of Pesticides:
Determination of Bioconcentration Potential. Res. Rev. 44:
73-113 (1972).
Kramer, P.J. and T.T. Kozlowski. Physiology of Trees. McGraw-
Hill Book Company, Inc., New York. Chapter 11-12 (1960).
Lang, A. Clark and Lubs Acid-Base Indicators. Handbook of
Chemistry. Handbook Publishers, Inc., Sandusky, Ohio, p. 11-
27-28 (1949) .
Leo, A.J. Relationships between Partitioning Solvent Systems.
Advances in Chemistry Series 114. American Chemical Society,
Washington, D.C. (1972).
Leo, A.J., C. Hansch, and D. Elkins. Partition Coefficients and
Their Uses. Chem. Rev., 7JL:525 (1971).
Lichtenstein, E.P. and K.R. Schultz. Volatilization of Insecti-
cides from Various Substrates. J. Agr. Food Chem. 18 (5);814-
819 (1970).
Lincer, J.L., J.M. Solon, and J.H. Nair, III. DDT and Endrin
Fish Toxicity Under Static Versus Dynamic Bioassay Conditions.
Trans. Amer. Fish. Soc. 99^(1) :13-19 (1970).
MacKay, D. and A.W. Wolkoff. Rate of Evaporation of Low-
Solubility Contaminants from Water Bodies to Atmosphere. Evn.
Sci. & Tech. 7_(7):611-614 (1973).
McCraren, J.P., O.B. Cope, and L. Eller. Some Chronic Effects
of Diuron on Bluegills. Weed Science r7(4):497-504 (1969).
Meikle, R.W., N.H. Kurihara, and C.R. Youngson. A Bioaccumula-
tion Study Utilizing DDT and A Mosquito Fish, Gambusia sp., in an
Aquatic Environment. Unpublished Report. Dow Chemical U.S.A.,
Walnut Creek, California. May 2 (1972).
122
-------
Metcalf, R.L., O.K. Sangha, and I.P. Kappoor. Model Ecosystem
for the Evaluation of Pesticide Biodegradability and Ecological
Magnification. Env. Sci. and Tech. 5_(8) :709-713 (1971) .
Neely, W.B., D.R. Branson, and G.E. Blau. Predicting the Bio-
concentration Potential of Organic Chemicals in Fish. Unpub-
lished Report. The Dow Chemical Company, Midland, Michigan
(1974).
Premdas, F.H. and J.M. Anderson, The Uptake and Detoxification
of C^-4 Labeled DDT in Atlantic Salmon Salmo solar. J. Fish.
Res. Board Canada £0:827-837 (1963).
Reinert, R.E. Pesticide Concentrations in Great Lakes Fish.
Pest. Mont. Jrnl. !3_(4) .-233-240 (1970).
Reinert, R.E. Accumulation of Dieldrin in an Algae (Scenedesmus
obliquus), Daphnia magna, and the Guppy (Poecilia reticulata).
j. Fish. Res. Board, Canada £9(10):1413-1418 (1972"H
Reinert, R.E., and H.L. Bergman. Residues of DDT in Lake Trout
(Salvelinus namaycush) and Coho Salmon (Oncorhynchus isutch)
from the Great Lakes. J. Fish. Res. Board, Canada (1974).
Rodgers, C.A. and D.L. Stalling. Dynamics of an Ester of 2,4-D
in Organs of Three Fish Species. Weed Science 2_0(1) : 101-105
(1972).
Sanders, H.O. and J.H. Chandler. Biological Magnification of a
Polychlorinated Biphenyl (Aroclor® 1254) from Water by Aquatic
Invertebrates. Bull. Env. Contam. & Toxic. 7_(5) :257-263 (1972).
Skelly, N.E. and L.L. Lamparski. Laboratory-Simulated Environ-
mental Study for 2,4,5-T Acid and Its Butyl Ester-Partition
Coefficients. Unpublished Report. The Dow Chemical Company,
Midland, Michigan. January 17 (1974).
Smith, G.E. and B.G. Isom. Investigation of Effects of Large-
Scale Applications of 2,4-D on Aquatic Fauna and Water Quality.
Pest. Mon. J. 1(3):16-21 (1967).
ith, G.N., B.S. Watson, and F.S. Fischer. The Metabolism of
C O,0-Diethyl 0-3,5,6-trichloro-2-pyridyl Phosphorothioate in
FishT ~J. Econ. Ent. 59_(6) : 1464-1465 (1966).
Smith, G.N., F.S. Fischer, and R.J. Axelson. The Volatilization
and Photodecomposition of Plictran® Miticide. Unpublished
Report. The Dow Chemical Company, Midland, Michigan. February
(1970).
123
-------
Smith, G.N., Y. Taylor, and B.S. Watson. Ecological Studies on
Chlorpyrifos. Unpublished Report. Chemical Biology Research,
The Dow Chemical Company, Midland, Michigan. Nov. 14 (1972).
Smith, G.N., Y.S. Taylor, and B.S. Watson. Ecological Studies
on Dalapon (2,2-Dichloropropionic Acid). Unpublished Report.
The Dow Chemical Company, Midland, Michigan. June 12 (1972a).
Smith, G.N., Y.S. Taylor, B. S. Watson. Ecological Studies
on Chlorpyrifos. Unpublished Report. The Dow Chemical Company,
Midland, Michigan. Nov. 14 (1972b).
Spector, W.S. Handbook of Biological Data. W.S. Saunders
Company, Philadelphia (1956).
Stevenson, F.J. Organic Matter Reactions Involving Herbicides
in Soil. J. Environ. Quality H4) :333-343 (1972).
Sturkie, P.O. Avian Physiology. Second Edition. Cornell
University Press. Ithaca, New York (1965).
Torkelson, T.R., R.M. Kary, E.A. Pfitzer, W.E. Reinhart, and
T.F. Hatch. The Uptake Storage and Elimination of Inhaled
1,1,1-Trichloroethane in the Rat. University Microfilm 67-3045.
Ann Arbor, Michigan (1966).
Walker, C.R. Chemicals and Their Effects on Our Aquatic Envi-
ronment. Presented at the 24th Annual Meeting of the SE Weed
Science Society. Memphis, Tennessee. January 19-21 (1971).
Weber, J.B. Interaction of Organic Pesticides with Particulate
Matter in Aquatic and Soil Systems. Fate of Organic Pesticides
in the Aquatic Environment. Advances in Chemistry Series 111.
American Chemical Society, Washington, D.C. (1972).
Weber, W.J., Jr. and J.P. Gould. Sorption of Organic Pesticides
from Aqueous Solution. Chapter 23. Advances in Chemistry
Series 60. American Chemical Society, Washington, D.C. (1966).
Wershaw, R.L., P.J. Bucar, and M.C. Goldberg. Interaction of
Pesticides with Natural Organic Material. Environ. Sci.
Technol. 3_:271-273 (1972).
Whitney, W.K. and E.E. Kenaga. Distribution and Sorption of
Liquid Fumigants Applied to Wheat by Recirculation. J. Econ.
Entomol., S3(2):259-261 (1960).
Whitney, W.K. and E.E. Kenaga. Bioassay Experiments to Deter-
mine the Volatility of Tricyclohexyltin Hydroxide. Unpublished
Report. The Dow Chemical Company, Midland, Michigan. April
(1966) .
124
-------
Youngson, C.R. and R.W. Meikle.14The Effect of Water Tempera-
ture on the Bioaccumulation of C-DDT by Mosquito Fish,
Gambusia. sp. Unpublished Report. Dow Chemical U.S.A., Walnut
Creek, California. April 26 (1972).
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PESTICIDE TRANSPORT AND TRANSFORMATION IN PLANTS
D. Stuart Frear*
United States Department of Agriculture
Julius J. Menn**
Stauffer Chemical Company
Pesticide use for crop protection in the United States has increased
dramatically over the last 20 years. Sales at the user level ($MM) in 1975
were estimated at 1,780 with a projected increase to 2,955 by 1980. The most
impressive gains have been in the use of herbicides (651), followed by
insecticides (25%) and fungicides (61). In the past ten years, increased
registration requirements and environmental safety concerns have prompted
rapid developments in research on the behavior and fate of these chemicals in
higher plants. Major pathways of absorption, movement, and metabolism have
been established for many herbicides and insecticides and a limited number of
fungicides.
Metabolism studies have shown that pesticides undergo similar biotrans-
formations in both plants and animals. Principal reactions include:
oxidation, reduction, hydrolysis, and/or conjugation. Conjugation reactions
are of particular importance in plants because, in contrast to animals,
conjugated plant metabolites are not excreted. Instead, they may be stored or
incorporated into insoluble "terminal" residues and ultimately degraded in the
environment or ingested by animals, including man.
Pathways of metabolism are affected by pesticide application methods and
different routes of absorption by the plant. In the soil, pesticides may be
transformed by microorganisms prior to root uptake while foliar applications
may result in photolytic and/or hydrolytic action prior to absorption by fruit
or foliage. Tissue differences in metabolism also may be a factor in the
disposition of pesticide metabolites. Other factors that may affect the
behavior and fate of pesticides in plants include: interactions with other
pesticides or chemicals, growth and development, environmental stress,
nutrition, disease and genetic variations.
*Metabolism and Radiation Research Laboratory, United States Department of
Agriculture, Agricultural Research Service, State University Station, Fargo
North Dakota 58102. '
**Biochemistry Department, Mountain View Research Center, Stauffer Chemical
Company, Post Office Box 760, Mountain View, California 94042
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Selected examples of herbicide and insecticide metabolism studies are
presented to illustrate the advantages, disadvantages, and limitations of
current research approaches to investigations of pesticide uptake and
transformation in higher plants.
INSECTICIDE STUDIES
Recent plant metabolism studies (22, 24, 25) have focused on three
thioaryl organophosphorous insecticides: fonofos (0_-ethyl S_-phenylethyl-
phosphonodithioate), N-2596 (0-ethyl S-4-chlorophenyl ethylphosphonodi-
thioate), and carbophenothion S-{(p-chlorophenylthio)methyl}0,0,diethyl-
phosphorodithioate. The metabolic fate of these compounds in animals was
reviewed recently (26).
The fate of fonofos was studied in Irish potatoes as a representative
root crop. In separate but identical experiments, sprouting potato pieces
were planted in soil containing 2.64 ppm (a-ethoxy-^C) or (phenyl-^C)-
fonofos. Plant material, including foliage, tuber peel, and pulp was analyzed
through 87 days after planting (22).
The proposed metabolic pathway of fonofos in the potato plant is shown in
Figure 1. Metabolites were isolated and identified by thin-layer chroma -
tography, radio-gas liquid chromatography, hydrolysis, enzymatic cleavage,
derivatization and mass spectrometry. Fonofos is metabolized extensively to
phosphonic acid derivatives; 0-ethylethane-phosphonic acid (EOF) and 0-
ethylethanephosphonothioic acid l^TTP). Only trace amount of the 0-ethyl S-
phenylethylphosphonothiolate (oxon) were recovered suggesting that thTs
metabolite may be a reactive intermediate and degrades rapidly to EOF and
thiophenol (PSH). The leaving thiophenyl moiety of fonofos and/or its oxon is
metabolized via S-methylation and sulfoxidation to methyl phenyl sulfide
(PhSMe), methyl phenyl sulfoxide (PhSCMe), methyl phenyl sulfone (PhS02Me) and
unidentified polar products, possibly conjugates. Based on the overall
similarity of the metabolic pathway of fonofos in animals (23) and the plant,
it is suggested that the polar plant products contain the PhS02Me moiety. The
S-methylation reaction provides an efficient means for thiophenol
detoxification and has not been reported previously in plants.
Metabolism studies with (phenyl-l ''C) N-2596 in corn plants are summarized
in Figure 2. Plants were grown to maturity in soil treated at the rate of 6.0
ppm N-2596. In addition to S-methylation and sulfoxidation, the cleaved 4-
chlorothiophenyl moiety was oxidized to 4-chlorophenyl sulfonic acid (4-
ClPhS03H) by another pathway. The sulfonic acid was the major "terminal"
metabolite of N-2596 in the plant and accounted for 48.71 of the recovered
radiocarbon. This metabolite was also identified in rat urine (27). Again,
the 0-ethyl S-4-chlorophenylethanephosphonothiolate (oxon) appears as a very
minoF metabolite in the plant, but may serve as a reactive intermediate in the
formation of 4-chlorothiophenol (4-C1PSH) and subsequent metabolic products.
However, the same metabolic products could also arise directly from cleavage
of N-2596. It is noteworthy that apparently no thioaryl hydroxylation
products were detected in plants either as free phenols or as conjugates. Of
the total radiocarbon recovered in plant tissues, 75% (4763 ppb) was
identified, 11% (697 ppb) were unknown products and 15% (970 ppb) was ' "bound"
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or unextractable radiocarbon. The total radiocarbon in mature corn plants was
calculated as 6.43 ppm equivalents of N-2596.
Carbophenothion, with a thio-ether moiety, presents a more complex
metabolic pathway in animals (3, 26) and plants (2, 25). Under field
conditions, following application to lettuce (2), carbophenothion was oxidized
to its sulfoxide (II) and sulfone (III) and to the thiolophosphate CIV) and
its sulfone (VI) (Figure 3). Trace levels of these oxidation products were
present up to 14 days after treatment. When (phenyl-llfC) carbophenothion was
applied as an emulsion to foliage and maturing fruit of a greenhouse-grown
orange tree, much of the dose was lost through volatilization and, to a lesser
extent, by metabolic transformations (24), Thin-layer chromatographic and co-
chromatographic analyses of plant tissue extracts with reference standards
established the presence of carbophenothion and all five oxidation products
(II, III, IV, V, and VI), in the foliage and the orange peel but not in the
juice and pulp. Of the applied radiocarbon, polar unknowns accounted for 7.1%
in foliage, 13.1% in peel, and 0.5% in juice and pulp. These studies also
established that essentially no radiocarbon was translocated to untreated
fruit and foliage.
As indicated in the introduction, these three studies are indicative of
some of the difficulties encountered in the isolation and identification of
polar plant metabolites and "bound" residues. Furthermore, as indicated in
the case of carbophenothion, it is difficult to separate photolytically
induced biotransformation products from those formed by action of the plant
itself.
HERBICIDE STUDIES
Metabolism studies with monuron {3-(4-chlorophenyl)-l,l-dimethylurea},
other substituted 3-(phenyl)-l,l-dimethylurea herbicides, and their
metabolites have established the major pathways of urea herbicide metabolism
in cotton and other plant species (7, 8, 10) (Figure 4). An initial
sequential oxidation of N-methyl groups is catalyzed by a microsomal mixed
function oxidase (5, 7, 28, 36). Unstable N-hydroxymethyl intermediates are
either conjugated as 0-glucosides or degraded rapidly to less toxic
demethylated products and formaldehyde (5, 7, 8, 37). Hydrolytic formation of
substituted anilines is negligible. A second oxidative pathway of urea
herbicide metabolism has been reported recently (10, 20, 21). Monuron and its
demethylated metabolites, 3-(4-chlorophenyl)-l-methylurea and p_-
chlorophenylurea, may also be aryl hydroxylated and conjugated as phenolic
glucosides.
Comparative metabolism studies with tomato, pepper, cotton, okra, peanut,
soybean and tobacco plants show that diphenamid (N,N-dimethyl-2,2-diphenyl-
acetamide) is metabolized primarily via a sequential oxidative N-dimethylation
pathway similar to the substituted 3-(phenyl)-l,l-dijneth.ylurea herbicides (14,
15, 16, 17) (Figure 5). Aryl hydroxylation is a minor pathway in most of the
plant species studied and hydrolysis of the amide bond is negligible. Two
major glycoside conjugates have been isolated from diphenamid-treated tomato
plants and identified as the glucoside and the gentiobioside of the initial
oxidative N-demethylation intermediate, N-hydroxymethyl-N-methyl-2,2-di-
128
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phenylacetamide (13). Low level ozone fumigation (10-34 pphm) of diphenamid-
treated tomato and pepper plants stimulates glycoside formation, but has
little effect on root absorption, translocation, or pathways of metabolism
(13, 14, 15, 16).
Three metabolic and detoxication pathways have been established for sub-
stituted 2-chloro-s-triazine herbicides in higher plants (31) (Figure 6). The
principal pathway in tolerant plants involves a rapid initial conjugation with
glutathione (18). The enzyme responsible for glutathione conjugation, a
glutathione S-transferase, has been isolated and partially characterized from
corn (6, 7). It is a major factor in the tolerance and selectivity of 2-
chloro-s_-triazines in corn, sorghum and sugarcane (18, 29, 30, 32). Recent
studies (19) show that initial glutathione conjugate formation is followed by
a series of additional biotransformations in sorghum. The heterocyclic s_-
triazine ring structure remains intact and appears to be incorporated into
insoluble plant residues (31). Feeding studies with rats and sheep show that
insoluble plant residue fractions are rapidly excreted in the feces and not
incorporated into body tissues (1).
In studies with excised pea and peanut tissues and with peanut cell
suspension cultures, the initial metabolic reaction of flurodifen (2,4'-
dinitro-4-trifluoromethyl-diphenylether), is a glutathione S-transferase
catalyzed cleavage of the diphenylether bond (9, 33) (Figure 7). Cleavage
products of the reaction are S-(2-nitro-4-trifluoromethylphenyl)-glutathione
and p_-nitrophenol. The phenolic cleavage product is rapidly conjugated with
glucose to yield p_-nitrophenyl-B-D-glucoside. Subsequent metabolism of the
flucoside results in the formation of p-nitrophenyl-6-0-malonyl-3-D-glucoside
(34). Further metabolism of the glutathione conjugated cleavage product also
occurs and recent studies (35) have identified S-(2-nitro-4-trifluoro-
methylphenyl)-N-malonyl-cysteine as a major fluorodifen metabolite in peanut.
Cisanilide (cis-2,5-dimethyl-1-pyrrolidinecarboxanilide) metabolism
studies with excised leaves and cell suspension cultures of carrot and cotton
have been compared (11). Initial oxidation products, 2,5-dimethyl-l-
pyrrolidine-4'-hydroxycarboxanilide and 2,5-dimethyl-3-hyroxy-l-
pyrrolidinecarboxanilide, are conjugated as 0-glucosides (Figure 8). Little,
if any, hydrolysis of the herbicide molecule occurs. Recent studies indicate
that the initial phenol oxidation product of cisanilide metabolism (2,5-
dimethyl-l-pyrrolidine-4'-hydroxycarboxanilide) is the precursor of a "bound"
residue fraction associated with the cell wall (12). Animal feeding and soil
degradation studies indicate that the bioavailability of this "bound" residue
fraction is limited.
CONCLUSION
Future research on pesticide transport and transformation in plants
should include: the development of better methods and new techniques for the
isolation, identification, and analysis of metabolites, degradation products,
and terminal residues; increased studies on pesticide interactions; additional
studies to determine the significance of environmental stress and genetic
variation of factors affecting pesticide behavior, persistence and fate; and
129
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expanded efforts to isolate and characterize key enzymes responsible for
pesticide metabolism and detoxication.
REFERENCES
1. Bakke, J. E., R. H. Shimabukuro, K. L. Davison, and G. L. Lamoureux.
1972. Chemosphere. 1:21-24.
2. Coffin, D. E. 1964. J. Assoc. Off. Anal. Chem. 47:662-667.
3. DeBaun, J. R. and J. J. Menn. 1976. Science. 191:187-188.
4. Frear, D. S. 1968. Science. 162:674-675.
5. Frear, D. S., H. R. Swanson, and F. S. Tanaka. 1969. Phytochemistry
8:2157-2169.
6. Frear, D. S. and H. R. Swanson. 1970. Phytochemistry. 9:2123-2132.
7. Frear, D. S., H. R. Swanson, and F. S. Tanaka. 1972. In: Structural
and Functional Aspects of Phytochemistry, Academic Press, New York. pp
225-246.
8. Frear, D. S. and H. R. Swanson. 1972. Phytochemistry. 11:1919-1929.
9. Frear, D. S. and H. R. Swanson. 1973. Pest. Biochem. Physiol. 3'473-
482.
10. Frear, D. S. and H. R. Swanson. 1974. Phytochemistry. 13:357-360.
11. Frear, D. S. and H. R. Swanson. 1975. Pest. Biochem. Physiol. 3:73-80.
12. Frear, D. S., H. R. Swanson, and K. L. Davison. 1975. Abstract Number
11, PEST, American Chemical Society Meeting.
13. Hodgson, R. H., D. S. Frear, H. R. Swanson, and L. A. Regan. 1973. Weed
Sci. 21:542-549.
14. Hodgson, R. H., K. E. Dusbabek, and B. L. Hoffer. 1974. Weed Sci
22:205-210.
15. Hodgson, R. H. and B. L. Hoffer. 1974. Abstract Number 38, Weed Science
Society American Meeting, pp. 17-18.
16, Hodgson, R. H. and B. L. Hoffer. 1975. Abstract Number 170, Weed
Science Society American Meeting, pp. 64-65.
17. Hodgson, R. H. and B. L. Hoffer. 1976. Abstract Number 197. Weed
Science Society American Meeting, p. 82.
18. Lamoureux, G. L., L. E. Stafford, and R. H. Shimabukuro. 1972. J. Agr
Food Chem. 20:1004-1010.
130
-------
19. Lamoureux, G. L., L. E. Stafford, R. H. Shimabukuro, and R. G, Zaylskie.
1973. J. Agr. Food Chem. 21:1020-1030.
20. Lee, S. S. and S. C. Fang. 1973. Weed Res. 13:59-66.
21. Lee, S. S., D. A. Griffin, and S. C. Fang. 1973. Weed Res. 13:234-235.
22. McBain, J. B., L. J. Hoffman, and J. J. Menn. 1970. J. Agr. Food Chem.
18:1139-1144.
23. McBain, J. B., L. J. Hoffman, J. J. Menn, and J. E. Casida. 1971. Pest.
Biochem. and Physiol. 1:356-365.
24. McBain, J. B., J. P. Wren, and J. J. Menn. 1976. Unpublished data.
25. Menn, J. J. 1972. In: Degradation of Synthetic Organic Molecules in
the Biosphere, National Academy of Science, Washington, D. C. pp. 206-
243.
26. Menn, J. J., J. R. DeBaun, L. J. Hoffman, and J. H. Ross. 1975. In:
Pesticides, G. Thieme Publishers, Stuttgart, pp. 382-387.
27. Miaullis, J. B., L. J. Hoffman, J. R. DeBaun, and J. J. Menn. 1976.
Manuscript submitted to J. Agr. Food Chem., November 1976.
28. Rusness, D. G. and D. S. Frear. 1973. J. Exptl. Bot. 24:272-294.
29. Shimabukuro, R. H., H. R. Swanson, and W. C. Walsh. 1970. Plant
Physiol. 46:103-107.
30. Shimabukuro, R. H., D. S. Frear, H. R. Swanson, and W. C. Walsh. 1970.
Plant Physiol. 47:10-14.
31. Shimabukuro, R. H., G. L. Lamoureux, D. S. Frear, and J. E. Bakke. 1971.
In: Pesticide Terminal Residues, Butterworths, London, pp. 323-342.
32. Shimabukuro, R. H., W. C. Walsh, G. L. Lamoureux, and L. E. Stafford.
1972. J. Agr. Food Chem. 21:1031-1036.
33. Shimabukuro, R. H., G. L. Lamoureux, H. R. Swanson, W. C. Walsh, L. E.
Stafford, and D. S. Frear. 1973. Pest. Biochem. Physiol. 3:483-494.
34. Shimabukuro, R. H., W. C. Walsh, G. E. Stolzenberg, and P. A. Olson.
1975. Abstract Number 171, Weed Science Society American Meeting, p.
65.
35. Shimabukuro, R. H., W. C. Walsh, G. E. Stolzenberg, and P. A. Olson.
1976. Abstract Number 196, Weed Science Society American Meeting, p.
81.
36. Tanaka, F. S., H. R. Swanson, and D. S. Frear. 1972. Phytochemistry.
11:2709-2715.
131
-------
37. Tanaka, F. S., H. R. Swanson, and D. S. Frear. 1972. Phytochemistry.
11:2701-2708.
-OCH3
EOP-CH:
A
I
C2H5
EOP
A
ETP
i
-SCH3
ETP-CH:
Oxon
\
Fonofos
"O
PSH
PhSMe
S-CH
PhSOMe
1
-CH,
CONJUGATES
Figure 1. Proposed metabolic pathway of fonofos in potato plant (22).
132
-------
Cl
s-
OC2H5
N 2596
17 ppb, 0.3%
C'\ /
4-CIP3H
i
o
4-CIPhSM«
4-CIPhSOM«
67 ppb, 1,0%
i
Cl
S-CH,
II O
0
4-ClPhS02Me
1526 ppb, 23.7%
Cl- sOH
4-CIPhSOH
Cl
OH
4-CIPhS02H
1
0
-S-OH
II
0
4-CIPhSOjH
3130 ppb, 48.7%
Figure 2. Proposed metabolic pathway of N-2596 in mature corn plants.
133
-------
s
II
(C2H60)2PSCH2S
I
I /O
Cl
L\ 0
0 0
(C2H50)2PSCH2S-R
0
VI
L = Lettuce
0 - Orange
Figure 3. Oxidative metabolism of carbophenothion in lettuce and orange.
134
-------
MtTHANOL-INSOLUBLE
RESIDUE
"UDPG< GLUCOSYL "MICROSOMAL "MICROSOMAL ' "UDPG- GLUCOSYL
TRANSFERASE" N-DEMETHYLASE" ARYL HYDROXYLASE" TRANSFERASE"
Figure 4, Monuron metabolism in plants (8, 10, 20, 21).
135
-------
U)
en
"UDPG: GLUCOSYL
TRANSFERASE"
"MICROSOMAL
N-OEMETHYLASE"
"MICROSOMAL
ARYL HYOROXYLASE"
"UDP6= GLUCOSYL
TRANSFERASE"
Figure 5. Diphenamid metabolism in plants (14, 15, 16, 17).
-------
OH S^
"N-DEALKYLATION"
*
OH ^X^
N-X^N
J^lll
H2N IjT NR2orR,
"ti_r\rAi ifvi ATirklJ1*
BENZOXAZINONE
CATALYZED HYDROLYSIS
^S
OLUTATHIONE
S-TRANSFERASE
^^ "N-DEALKYLATION" ^S.
x^ t ^Ss
1
Cl
jL OLUTATHIONE
N^_TN ____— S-TRANSFERASE
Jfll
M fcl tJ fcl D
'CARBOXYPEPTIDASE'
1
f
WvSCyt
*£**
1>J| Jl
"t{j ** H"*"''
"r-OLUTAMYL
TRANSPEPTIDASE"
1
SCy,
"N-DEALKYLATION
BENZOXAZINONE
CATALYZED HYDROLYSIS
HNCy*
HOOC-CH-CHt-S-CHg-CH-COOH
NH. HN
R, • -CHj-CHj
UNIDENTIFIED
SOLUBLE AND INSOLUBLE
PRODUCTS
(T) • PHYTOTOXIC
(PT) « PARTIALLY DETOXIFIED
(N) • NON-PHYTOTOXIC
Figure 6. Atrazine metabolism in sorghum (19).
137
-------
CO
CO
CHOH
"UDPG<
glucosyl
transferase"
Glutathione
S-transferase
0
ii
HOOC-CHt-C-0-CH2
'Malonyl CoA*
molonyl
transferase"
"Corboxy peptidase" "T-glutamyl transpeptidose"
SG ^ ,
"Malonyl CoA= malonyl transferase"
'Shimabukuro et al., 1973; 1975; 1976
Figure 7. Fluorodifen metabolism in peanut (33, 34, 35).
-------
"UDPG=glucotyl
transftroM*
GIcO
CH,
'UDPG'Qlucotyl
tran*ftrof«"
CH,
N-C-N
H
-OGIc
CH9
Figure 8. Cisanilide metabolism in plants (11, 12).
139
-------
PATHWAYS OF PESTICIDE DISSIPATION AND
DECOMPOSITION
Weintraub F.P., Vylegzhanina G.F., Dron L.P., Kejser L.S.,
Nesterova I.P., Patrashku F.I.
Ail-Union Institute for Biological Methods of Plant
Protection, Kishinev
Modern idea of pesticide danger is connected with their de-
composition and transformation in the environment and circulation
of the parent compounds as well as metabolites in all the links
of their transformation cycle. Thus it is important to determine
the factors, responsible for decrease and dissipation of the
compounds.
For some years the scientific workers of our laboratory on
analytical chemistry have been studying the effects of light,
temperature, humidity, wind speed, hydrolysis and other factors
on the stability of gardona, methylnitrophos, cianox, phosalone,
phthalophos( imidane)and s-triazines on/in plant, soil by means
of thin-layer-, gas chromatography and other methods of analysis.
In model studies under laboratory and field conditions the
sunlight and air temperature at which the interaction with
140
-------
Plant occurs, were proved to be the main factors, that con-
e "to gardona decrease and conversion on the treated apple
ardona, exposed to the sunlight, decomposes into a number
Products, the main of them being cis-isomer of gardona. The
ganochlorine metabolites (2,4,5-trichloroacetophenone, 2,4,5-
lciilorophenoacyl chloride and oth.) were detected in signifi-
y lower amounts. The kinetics of gardona phot ode compos it ion
Atasl .a
ormation of the photolysis products under UV- and sunlight
"1 Vl^*!
ence nav® been studied. The kinetic photodecomposition
vpig.I) of chemically pure and technical gardona under
&*•* influence show that the technical product decomposes
n " studies on the dynamics of gardona decrease on apple
fruits (Pig. 2) protected and non-protected against
es
+u
, tne latter was shown to be an essential factor in the
,VP
°i gardona decomposition.
11 "tiie interaction of gardona with the plant other meta-
are also formed, of which 2,4,5-trichlorophenyl ethanol
«y»xi v
anci bound state is the most interesting one. In this case
Q.A /\
P°8ition rate of gardona depends on air temperature. Other
f ft f\ 4«
8 the environment (wind, rain falls) influence insig-
gardona decrease off the plant.
ile studying the evaporation rates of methylnitrophos-
..
lmethyl-0-(3-methyl-4-nitrophenyl)-thio-phosphate and cia-
f\
141
-------
50
10
10
70
10
30
50 h
-C/T, ,!• '.'< ' i '•
Pig-. I. The kinetic curves of the photoalteration of
Gardona by sunlight.
The irradiation: I - of the thin film of
chemical pure Gardona; II - of the thin-
film of wettable powder.
The kinetics curves: a - Gardona, b- cis-
isomer of Gardona, c - the ratio cis/trans,
d. - 2,4,5 -trichlorophenacyl chloride.
nox-0,0-diraethyl-0-(p-cyanophenyl)-thiophosphate under controlled
laboratory and field conditions*the compounds were shown to
disappear quickly from the glass surface. Supposing that the
process of insecticide loss is similar to the process of radio-
142
-------
100
8
12
8
12
days
Fig.2. The dinamics of Gardona breakdown on leaves (A)
and apples (B).
I - protected from sunlight
2 - exposed to direct sunlight
3 - dynamics of cis-isomer Gardona
4 - the duration of day light, hours
5 - min,temperature of air,
6 - max. temperature of air.
143
-------
active decay, the constants of loss rates and periods of their
"half-life" were calculated. These data are presented in Table I,
The lose rate sharply increases with the increase of air tempera-
ture and, hence, the substrate temperature. Humidity increase from
55+5% to 90+5$ influences evoporation to a less extent. Pig. 3
shows the curves of cianox loss in dependence on the sum of tempe-
rature, humidity, formulation effects and their interaction.
Methylnitrophos hydrolysis rate was studied in dependence on
the pH. Cianox hydrolysis was studied in dependence on medium pH
and temperature* The data obtained indicated that methylnitrophoe
and cianox as well as the oxygen analogue of the latter are rather
resistant to the hydrolysis in neutral and slightly acidic media.
In comparison with the initial compound cianox oxygen analogue is
hydrolyzed in neutral and slightly acidic media 2 times quicker.
Table I.
The half-life periods of methylnitrophos and cianox residues
on the glass surface at 20-22 and 40°C (air humidity 55+5%)
Compounds :Methylnitro- : Cianox, : Cianox,
phos, c.e. c.e. w.p«
The half-life : 20-22°
40°
17,0
9,3
29,1
2,8
21,1
2,1
c.e. - concentrate emulsion
w.p. - wettable powder
144
-------
Thus, methylnitrophos and cianoz are characterized by comparatively
high volatility but are rather resistant to the hydrolysis. Being
low polar insecticides they are mainly evaporated from the treated
surface* This is confirmed by our data on methylnitrophos and
150°
g
s
••••
o
1000
0)
H
O
500
^ 2
.-* 1
C.e.
Formulation
W.p.
8
The dependence of the volatility of cianox from
the main effects of: I - formulation,
2 - humidity, 3 - temperature,
4 - interaction of the factors.
The vertical line is L.S.D.Qc « 41,5 J^g
145
-------
cianox residue dynamics on apple fruits following treatment. As
far as the evaporation process depends on temperature to a great
extent, methylnitrophos and cianox are evaporated from treated
apples at hot weather (28-33°C) for I-3 days following spraying.
Phosalone is characterized by its relative hydrolytic resistance
Under laboratory conditions, at room temperature phosalone is
quickly hydrolyzed only in alkaline medium^in neutral medium this
process being rather slow* At pH 6 and less it is of no practical
value. At 60-70°C and pH 5 50% of phosalone is hydrolyzed during
90 hours,at pH 7 - about 80$ during 70 hours and at pH 9 phosalone
is completely hydrolyzed during 4 hours.
In laboratory tests it was shown that phosalone decomposes
slowly under UV- and sunlight. This leads to a greater residue
persistence in harvested crop. About 50% of phosalone residue de-
composes in the process of apple canning (blanching, pasteurization
while preparing juices, puree). No residues were detected in apple
juice.
Fhosalone was preserved in the soil for about 2 weeks, when
applied at rate of 3,0 kg/he.
Fhthalophos, exposed tothe sunlight on silicic acid thin layer
plates, decomposes quickly forming oxygen analogue, hydroxymethyl-
•
phthalimide, phthalimide and one unidentified compound, containing
phosphorus (Rf«0,0). The latter is formed in the greatest quantities.
The parent compound is detected during 10 days and theoxyscn ana-
logue - during 25 days. Under irradiation of phtalophos in film(after
solvent evaporation)oxygen analogue traces and the same unidenti-
146
-------
fied compound are formed. The phthalophos decomposition under lu-
miniscent lamp irradiation (450-700 nm) is identical to the decom-
position under sunlight. The period of phthalophos semidecomposition
was 35 hours* UV light accelerates photolysis processes (Fig.4)*
66
90
120 min
Pig. 4
The kinetics curves of the alteration
of Phtalophos and the formation of phthali-
mide under the action of UV-light.
I - phtalophos in water,
11 - phtalimide in water,
III - phtalophos in the thinfilm.
147
-------
It is to be noted that no oxygen analogue was detected when phtalophos
was irradiated on thinlayer plates. No hydroxymethylphthalimide and
phthalimide formation took place in the process of film irradiation*
This suggested the possibility that they were formed in the presence
of OH~ and Hv ions. Irradiation of phthalophos in an aqueous
solution by luminescent lamp and UV light confirms this fact. Hydroxy-
methylphthalimide and phthalimide were detected in 1-2 minutes, and
in 10 minutes - phthalimide only. These data can serve as an evidence
of phthalophos photohydrolysis in the presence of water.
The field test, where apple leaves and fruits were treated
with 50% phtalophos, confirms formation of hydroxymethylphthali-
igreater,
mide, phthalimide and unidentified compound, havingyfetention
time than phthalimide. Phthalimide quantity (Table 2) was not
more than 0,01-0,02 % from the detected quantity of phthalophos
in the interval of 3-15 days after treatment. No phthalimide was
found in the harvested crop. It is hydrolysis that is worth noting
among other factors promoting phthalophos decomposition. The
effect of temperature and precipitation is less.
In model tests essential influence of air temperature and
soil humidity on the process of sayfos (menazen) accumulation
on pea plants, grown from seeds treated by sayfos, was revealed
under controlled conditions. Moderate temperatures, sufficient
moisture promote the compound penetration from treated soil
to plants (Table 3). Under sunlight influence sayfos oxygen ana-
logue is formed on surfaces of treated plants. On the 25th day
its quantity exceeds sayfos content.
148
-------
Table 2
The dynamics of phtalophos and phtalimide on the apples
Bays :
following
treatment .
0*
I
2
3
7
10
15
24
36
Found
phtalophoa, mg/kg
4,3
3,9
4,4
4,0
2,7
2,5
2,0
0,5
0,1
: phtalimide, mg/kg
—
2,0
5,6
8,8
5,4
2,6
1,1
0,4
••
* two hours after treatment
The influence of soil characteristics and moisture on atra-
cine and prometrine persistence time was studied in 5 types of
soil with different organic matter content, pH value and absorp-
tion capacity. The levels of complete moisture capacity were
43, 60 and 755&« At equal moisture level atrapine persistence
depended on soil characteristics. Thus, at 60# of field moisture
capacity - 78-81% of herbicide was inactivated in typical,lixi-
vated and common black earths, 66$ - in grey forest soil • It
was soil moisture that was responsible for the atrasine persis-
tence time* At 75$ of field moisture capacity 78-93$ of the
compound was inactivated in black earths, at 45# - 52-6I5&. At
149
-------
Table 3
Influence of the soil humidity and temperature on the
sayfos content in plant
The soil humidity
(% absolute)
18
25
37
: Temperature ,
33-12
5,47
7,94
16,74
°o,
40-20
2,11
2,40
6,48
: Average by fac>
tor A,
LSD05 .1,07
3,79
5,17
11,61
Average by factor B
LSD05-I,94 I0'95 3'66 6'86
the same time soil characteristics didn't influence prometrine
persistence. At 60# of field moisture capacity - 9I-97S6 was inac-
tivated for 3 months in all kinds of soil. Besides, 2 months were
needed to complete prometrine inactivation at 75# of field moisture
capacity and a little bit more than 5 months - at 45£*
In field tests on maize simasine, atrazine, polytriazine and
agelon residue range was 0,06 mg/kg of soil at the end of vegeta-
tion period, depending on the precipitation quantity and intensity
in the stratum of 0-10 cm* Autumn and winter periods were charac-
terized by herbicide redistribution from the upper stratum (0-10
cm) to the depth of 40 cm with the residue of 0,05-0,11 mg/kg of
the soil*
150
-------
STUDIES OF THE BEHAVIOUR OF QRGANOPHOSPHORQOS
INSECTICIDES IN SOIL AND IN SOIL-PLANT SYSTEM
PETR07A T. M., NOVOZHIL07 K. 7.,
E7STIGNEYEVA T, A., KOPTTOVA P. I.
All-Union Research Plant-Protection Institute
Now in the Soviet Union organophosphorous insecticides
(chlorophos, carbophos, phosphamid, gardona, syfos, zaethil-
nitrophos and its analogues xaetathion, sumithion, folitnion
et al.) which penetrate directly or indirectly into soil are
widely used in agriculture for plant protection against Ar-
tjiropoda. In connection with it studies of the behaviour of
these insecticides in soil and also in soil-plant system are
of great interest both for proper rational use of these che-
micals for integrated control methods in plant protection and
for the solving of toxicologohygienic problems.
As it is knovm the insecticidal conversion in soil and
in plants is the process depending on many factors and chang-
ing under the influence of biological and nonbiological con-
ditions*
Considering the factors as a system determining the character
of the insecticidal "behavior in biological objects, it should be
151
-------
noted that of particular importance arc:
a) physical and chemical properties of the pesticide charac-
terizing the chemical "by the stability of not only its original
forms but also of its conversion products, as well as by its so-
lubility in different environments, volatility, diffusion rate,
persistence in different environments and so on;
b) methods of pesticidal use for the control of plant
pests in agriculture;
c) environmental conditions (temperature, precipitations,
solar radiation, air motion and so on);
d) soil features (its tyue and structure, the content af.
organic substances, pH value, the aggregation rate and 30 on)
and plant peculiarities (anatomo-morphological, physiologo-
biochemical ones)*
A great number of papers elucidating the importance of
nonbiological factors in the process of pesticidal conversion
was published for last years (NOVOZHIL07, PETROVA, 1974; J.SD-
VED, 1974, WAINTRAUB, 1974; KLISSENEQ, 1975, O'BRIEN, 1975,
FUKUTO, CROSBY, 1975 et al.). Over 20 reports were only dedi-
cated to this problem at the 3rd International Congress on
Chemistry of Pesticides which was held in Helsinki in 1974.
The majority of researchers considers physico-chemical
characteristics of pesticides to be one of the main factors
of their conversion.
152
-------
Our researches and the analysis of modern scientific li-
terature on this problem convince us that physico-chemical
characteristics of the pesticide, U7-rays and humidity (preci-
pitations) within first days after crop treatment with the che-
mical indeed are main indices in the system of factors of non-
biological nature. Model experiments in chambers with artifi-
cial climate corroborate insignificant influence of tempera-
ture and illumination (with the exception of UV-spectrum part)
on the rate of OFI destroying
3o, on the JOth day syfos content was the same when
temperature was 28° C and illumination - 300 watt/m and
2
500 watt/m , that made up 34—35^ from the original amount of
the pesticide; when illumination was 400 watt/m2 and t° 20°
and $0° the toxicant content was 37-36%, respectively from
its original amount*
The distribution of OPI in plant-soil-plant system is
also connected with physico-chemical characteristics. It is
noted that watersoluble insecticides are washed off by vvater
and they are translocated from one system to another one, as
for example, chlorophos» Chemicals scarecely soluble in ?;ater
(carbophos, syfos, gardona et al.) are waaied off only within
the first day after a plant treatment. The distribution of
Gardona in plants and in soil after spraying pea plants is
shown in Table !• The majority of organophosphorous insecticides
penetrating into the soil was found in maximum at the depth of
153
-------
0-3 cm under the conditions of normal moistening for loan aru
cii^rnozemic soil.
DISTRIBUTION OF GARDUHA III PLANTS AMD Iff SOIL
Days
after
treatment
0
I
4
8
II
15
Gardona content(m';Ag) in
upper part of the plant
one
treatment
I*, 9 ± I,*
I?,0 i 1,4
8,2 ± 0,9
5,0 t 0,15
n. d.
n. d.
two
treatments
16,2 t 1,25
14, 0 i I,*
7,8 1 0,96
2,9 1 0,3
1,3 ± 0,2
0,93 ± 0,1
lower part of the plant
one
treatment
2,1 ± 0,25
-
-
0,56 1 0,1
n. d.
n. d.
t;wo
treatments
6,0 + 0,2
4,0 1 0,1
2,1 ± 0,1
0,96 ± 0,09
0,48 ±o,I
0,43 i 0,05
in the depth of soil
0-3 cm
1,15 1 0,1
1,03 ±0,1
0,45 * 0,05
0,22 t 0,05
0,4 + 0,1
0,2 * 0,07
3 - 10 cm
0,57 + 0,1
0,5 t 0,03
0,25 t 0,01
0,11 ± 0,01
0,21 i 0,01
n. d.
The method of OPI application ezerta a significant ef-
fect on their dynamics. The product applied into soil £as dust
or granules)' is found in growing plants within 2-4 months
(Tables 2, 3, 4), whereas for the sprayed insecticide it
was found within 0.5 - 1.5 months (Table 5).
(the*
Studies oTTsyfos behaviour under field conditions of the
Leningrad region allowed to ascertain that half-life period
of syfos in pea and potato plants was 3-5 days for vegetation
plant spraying. The decrease of syfos content up to the level
of permittable residues in the USSR occurs in 5-7 days; the
154
-------
Toblo
DYNAMICS 0? CHIOnOfHOS IIT PIAMT3 AND IH SOIL
— — — —
SAMPLE
roots
ClOYW?
laevaa
Cabbage l«ava«
(Br-6«iee)
Soil
________ , , ____ — _ . .. -
Oilorophos content (mg/kg)
7
daya
25
15
112
53*
15
days
20
13,5
80
2*1
30
days
2,2
1,2
26
59,0
45
days
It*
0,3
11,4
18,3
60
days
0
0
3,3
4,2
90
daya
1,2
1,8
ZOO
daya
0,8
1,0
120
days
0,2
0,6
140
daya
0
x) 150 fcg/fca 7% toxic granules of ohlorophoa wero applied into aoil in May.
Table 3
AMOUNTS IN PiiA PLANTS AFTER SEED T
(2 kg/IQO kg Boed)
Teat
variant
Syfos content
daya after troafcmonta
in plants
30
60
75
in soil
75
In field
In glasobouBo.
5,1
5,7
2,7
3,5
0,1
0,5
0,2
0,15 - 0,1
0,01
155
-------
Tabla
8Y703 DTOAMIC3 IN PEA PIAMT3 AND IN SOIL At'TEH SEED TREATMENTS
I 976
Sample
plants
aoil
plants
aoil
Application rates
(kg./ 100 kg. seed)
2
3
Syfos content (nig/kg),
days after treatment
20
10,0
1,9
13,5
6,5
30
6,7
1,5
8,2
4,2
35
S5
0,9
4,2
2,2
40
4,0
0,9
4-,!
1,9
45
2,2
0,7
3,9
1,7
50
2,1
0,6
3,5
1,5
55
2,0
0,6
3,0
1,3
60
2,0
0,6
2,3
0,9
65
1,3
0,5
2,0
0,7
80
0,4
0,4
0,9
0,6
Table 5
DYNAMICS IN PIAMTS UF POTATO AND P.SA DKPEUDIHG
Qtl TUB HUrJBKB. OF TIlKA'i'UEMM 1975
(concentration of t>,/fr>a o,I >'» a. i. )
Crop
Pea
Potato
fea
Potato
No. at
treo'tmaats
I
II
Syi'os concent (ma/kg),
Jays afbor troatmont
0
2,5
3,0
4,0
4,2
I
1,6
2,0
3,5
3,o
3
1,0
1,1
^,o
3,1
5
0,0
«>,9
2,0
t,5
7
0,7
0,0
0,5
0,9
12
17
0,4
0,5
0,*
0,6
0,1
0,2
22
-
-
0,01
0,0'i
30
-
-
-
0,01
156
-------
product was found in the amount of 0.01 mg/kg within 30-
-35 days*
When pea seeds are treated with Syfos the toxicant pene-
trates intVySerial parts of plants and remains there at
0*5 - O.I ing/kg level within 50 - 70 days depending on climat-
t contentj
ic factors. The rates of sjfoafdecrease in pea and potato plants
are relatively constant and depend on the original insecticide
content in them (Tables 3, 4, 5)-
We consider the process of • . ; insecticidal conversion
in a biological object (in the plant, in soil) eu-s &. function
in the system of factors of biological and nonbiological nature.
;Ve emphasize first of all anatomo-morphological plant peculia-
rities in the system of factors^ as the distribution of the
toxicant in a plant is connected with there (Table 6).
Our researches with crops varyinr; in the anatomo-norpholc-
gical structure of leaves (pea, bean, tomato, cucumber and
cabbage plants) have shown that the toxicant distribution di-
rectly depends on leaf hairness, wax content in the cuticle,
lipids and other lipid-like substances and on their quality,
too*
As it should be expected, leaves with significant hair-
ness (cucumber, tomato plants) or a wax layer (cabbage plants)
had a more considerable amount of the insecticide on their sur-
face compared with pea and bean leaves. So the ratio of the
"surface" carbophos to the absorbed one was I : I in leaves
of cabbage and cucumber plants. This ratio was I : 1,5; 1:1,4
157
-------
Table 5
DISTHIBOTIOff 0? OSGASOIEOSPHOROUS IESSOTICIPSS
IN PLANT .LEAVES
^v Pesticide
Test PlantsX.
Cucuaber . . . • .
B 4 A 11 ••«••*•
Pea line i
Zelenozexr^ wax
Zeleoozarny ..
Acacia wax ...
Acacia emerald
Ratio of "surface" to "absorbed" insecticide
Xetathion
III
I t 0,3
I t 0.7
I t 1,2
I t 1.5
I t 0,3
I I 1,6
I t 0,6
I t 1,1
Itethjl-
nitroohoa
I t 0.3
I « 0,3
I t 0.7
I i I
I t 0.9
I l 0,6
I « 1,3
I * 0,*
I t I
Suaitiion
I I 0,4
I 1 0,4
I i 0,7
I : I
I t I
I * 0,7
I : 1,2
X t 0.6
I < I
Caroopuo z
I » T -7
J : I
I : 1,5
I t I ^
I : I
0,2 » I
I : I
0,1 i I
in .leaves of pea and bean plants, respectively. It should be
noted that the toxicant distribution in pea plants depends
to a great extent on the presence or absence of cuticle
waxes. Uae Mgher content of the "surface" Insecticide is
found In isogenic pea lines characterized by the presence of
a wax gene (Zelenozemy wax, Acacia wax) as compared with un-
wax pea lines (Zelenozerny unwax, Acacia emerald)*
The same regularity is also observed with other insecti-
cides*
Since the degradation rates in the "surface" and the ab-
sorbed insecticide are different, the toxicant distribution
158
-------
in plant leaves is undoubtedly of great importance in the
process of detoxication.
'fhe insecticide on epidermis surface (the "surface"
insecticide) is mainly destroyed under the influence of fac-
t77hereas.
tors of the nonbiological nature7/^Ee toxicant penetrated in-
to tissues ("absorbed11 one) degrades under the influence of
oxidation-reduction cell enzymes (Table 7) and hydrolytic ones
(Table 8).
Table 7
70K£ATIO!T IN PSA LIHSS
fflTH
P3HOXIDA3S ACTIVITT
?3A LIHES
Zelenozerny war
Acacia wax . • . . .
•.: u l k ......
. .:? rcovs^7 ......
".'cis^osclii^r .».
^taabovy 180 ..
Senator .......
Peroxidased activity
in ng of oxidized
pyrocatechol per I g
o£ protein
126
129
131
137
158
170
170
178
190
Oxicarbophoa contest,
forced froa 100 ag
of absorbed carbophos
in sag
5
7
7
10
X*
12
16
16
17
159
-------
Tiig EK.MOT3 00' TJJ.'.'.' nru:«n.mo cui/Yj
ffOK CAR&CU'HOa AJID MjJ'i:iii%>!I'lHC)P!IOS TU PISA PLAiTi'S
The sample
Lincoln x Karmazinovy
Lincoln
Days after
treatment
I
5
14
I
5
I*
I
5
I*
Carbophos
metabolites
monoacid
5,3
-
-
-
2,2
-
-
1,5
diacid
3,2
8,0
-
-
-
5,1
-
3,3
5,0
Methylnitrophoa
metabolites
desmethyl-
nitropaos
1,5
0,4
0,1
0,1
14
0,5
-
1,6
0,2
diraethyl-
thiophoafate
acid
!•*
0,1
-
-
2,3
traces
-
I.I
0,3
As it is known, the formation of oxidized metabolites is
connected, with the activity of oxidation-reduction enzymes,in.
particularv with peroxidase* On this basis we studied the
formation of oxicarbophos and oximethylnitrophos in pea lines
with different peroxidase activity of this enzyme•
Table 7 shows that larger amount of oxidized metabolite is
formed in lines with increased activity of peroxidase (Meteor,
Senator, Lincoln) as compared with Mulk, Acacia wax, Zeleno-
zerny wax with similar level of the "absorbed" insecticide.
Our studies with different plants la different periods
of their development indicate that formation of oxi-
dized forms of metabolites from "absorbed" metabolites occurs
160
-------
under the conditions of the most active metabolism, in parti-
cular, in spring, and also within the first days after a plant
treatment with the insecticide when defensive reactions mobi-
lize in response to the incorporation of tfae- aobatances which
are not characteristic of the organ I am*
Products of toxicant hydrolytical degradation are formed
in significant amounts along with oxidized forms. Their le-
vel correlates with the esterase activity, and the data ob-
tained for the separate lines and the interline hybrids
confirm it«
On the first day the products of hydrolytical insecticidal
conversion were already observed in the hybrid pea form with
the higher esterase activity, compared with the parent lines where
they appeared 5-7 days later.
Complex of the factors affecting the process of pesticidal
detoxication was studied in the wide scale under field conditions
with gardona*
Data on toxicant distribution in different plant parts
and in soil were obtained (Table 9)« 85,396 of the insecticide
were found in upper plant layer in 2 hours after a treatment
with gardona; 10*8$ of Gardona was found in lower layer, 3«5£
- in soil, and 8I.7$» I5«2£ and 3«I%, respectively, in 5 days*
As we see, the larger amount of the insecticide is found in
the upper part of the pea plant, and only 2-356 of the toxicant
penetrate into soil*
161
-------
Tablo 9
DIS'I'RIflllPICKl OP ri
1U_.PM4_ PlAlfT3 _A»D Hi SOIL
(Spraying according to moasurd system, r&coii'imnclad in the control
of pea peata under tius conditions of Chernovitny region)
Year,
number of treatments
One treatment
TV7\ L j , j
Vfry
Two treatments
One treatment
TY'lL
±Jfr
Two trcatimmts
Gardona content (nnyicg) in
upper part of plwitB
14,9 i 1,2
16,2 i 1,25
13,1 ± I. 6
15, J 1 J,*
lowor part of plants
2,1 1 0,25
I.&5 1 0,2
0,0 + 0,2
3,7 1 0,2
floil (0-3 cm)
1,15 t 0,15
I,? 1 0,20
0,6 + 0,0?
1,20 i o.ii
This regularity is valid for all the years ?rhen the experi-
ments were carried out. Similar data were also obtained for the
other crops. Our research into the significance of the factors
in detoxication process will provide an opportunity to substan-
tiate prediction of pesticide residues in "biological objects,
and in connection with it, to solve properly the practical prob-
lems of rational use of chemicals.
162
-------
METABOLISM OF FYRETHROID INSECTICIDES AND THIOCARBAMATE HERBICIDES
John E. GasIda #
University of California, Berkeley
ABSTRACT
Knowledge of the metabolism of pesticides contributes to an understand-
ing of their mode of action, selective toxicity, and residual persistence.
It also assists in the discovery of compounds with increased potency and
safety. Investigations at Berkeley with pyrethroid insecticides and thio-
carbamate herbicides using mammals, insects, plants and enzyme systems
illustrate these points.
PYRETHR03DS
Synthetic pyrethroids are possible replacements for chlorinated
hydrocarbons and other insecticides that lack appropriate toxicological and
persistence characteristics.
The first definitive step in understanding pyrethroid metabolism came
from studies on S-bioallethrin, pyrethrin I and other chrysanthemates with
housefly monooxygenase enzymes that showed the lability of the trans-methyl
group of the isobutenyl moiety (Fig. l) (1-3). These studies also: 1)
showed that methylenedioxyphenyl synergists for pyrethroids block the enzyma-
housefly
microsomes
monooxygenase
NADPH
Fig. 1. Metabolism of S-bioallethrin by the housefly
microsomal monooxygenase system (1-3)
"""Pesticide Chemistry and Toxicology Laboratory, Department of Entomological
Sciences, University of California, Berkeley, California $&720,u.S.A.
163
-------
tic oxidation; 2) stimulated others to prepare potent pyrethroids by re-
placing the isobutenyl moiety with less biodegradable substituents; and 3)
suggested the pathway later found to exist in Chrysanthemum cinerariaefolium
for biosynthesis of pyrethrin II. ""
Metabolic pathways for pyrethrin L» pyrethrin II and S-bioallethrin in
rats were defined by isolation of the [ CJ- or [3n]metabolites and
identification by nuclear magnetic resonance and mass spectrometry (Fig. 2)
(^-8). Major sites of oxidative attack are at the alcohol side chain,
CM,0
Fig. 2. Metabolism of pyrethrin I, pyrethrin II
and S-bioallethrin by rats (U-8)
164
-------
the isobutenyl moiety and the geminal-dimethyl group. There is little
or no hydrolysis of the cyclopropanecarboxylate ester group.
Bioresmethrin (1R,trans-resmethrin) is a photolabile but highly potent
insecticide. It has an extremely low acute toxicity for mammals whereas
the IRjCis-isomer is more toxic. Mouse liver microsomes hydrolyze 1R,trans-
resmethrin much more rapidly than lR,cis-resmethrin (Fig. 3) (9-1^)- On
Fig. 3-
10 20
Minutes
Metabolism of IR-resmethrin by mouse
liver microsomal esterases (9-1*0
a more general basis, they hydrolyze trans-cyclopropanecarboxylic acid
esters with primary alcohols at a much greater rate than they hydrolyze the
corresponding cis-esters with primary alcohols or the trans-esters with
secondary alcohols.
Fermethrin no longer has the biodegradable and photolabile substituents
present in earlier pyrethroids. The 1R,trans- and lR,cis-iscmers are
metabolized in rats by ester hydrolysis and hydroxylation of the geminal-
dimethyl group and the phenoxy ring (Fig. h) (15,16). The cis-isomer is
more persistent than the trans-isomer because of the large rate difference
in ester hydrolysis.
165
-------
\ /
0 Moyi
1-tf
ptrmethrin
• »
1 \I
Fig. U. Metabolism of IE .trans-permethrin (t^per) and lR,cis-permethrin
(c_-per) by rats (15, 16)
Mouse liver microsonal oxidase and esterase systems were used to
examine the structure-biodegradability relationships of ^k pyrethroids.
Introduction of an a-cyano substituent in the alcohol to increase the in-
secticidal potency leads to compounds (NRDC lU9 and S-5602) that are both
slowly hydroOyzed and slowly oxidized (Fig. 5)
NROC 149
S-5602
Fig. 5- a-Cyano pyrethroids resistant to metabolism by mouse
liver microsomal monooxygenase and esterase systems
Stereospecificity is sometimes encountered in the preferred site of
monooxygenase attack. For example, the geminal-dimethyl group of IR,trans
166
-------
permethrin is oxidized by mouse and rat liver enzymes specifically at the
cis-methyl group while the IS,trans-isomer is oxidized only at the trans-
methyl group (Fig. 6) (17). Oxidation of the geminal-dimethyl group in the
1R- and lS,cis-isomers is less specific.
The continuing studies are examining new pyrethroids and a greater
variety of organisms (cows, chickens and various insect species).
IR. trans IS. trans
Fig. 6. Stereospecificity in mouse liver microsomal monooxygenase
metabolism of 1R,trans- and lS,trans-permethrin (17)
THIOCARBAMTES
Thiocarbamate herbicides were previously reported to undergo hydrolysis
and further metabolism of the mercaptan and amine in mammals and plants.
In contrast, the present studies show the importance of non-hydrolytic
pathways for thiocarbamate metabolism.
Investigations with mouse liver enzymes establish that thiocarbamates
undergo microsomal monooxygenase attack to form the sulfoxide and N-
dealkyl derivatives. The sulfoxide is then rapidly cleaved by the GSH §-
transferase system, forming the GSH conjugate (Fig. 7) (18-20). Further
metabolism of the GSH conjugate in rats yields the cysteine conjugate
and a variety of other metabolites including the mercapturic acids (Fig. 7)
(21,22). An additional but undefined pathway in rats does not involve
the sulfoxide intermediate in cleaving a portion of the thiocarbamate dose
(22).
The thiocarbamate sulfoxides are also formed in plants and are usually
more potent herbicides and often cause less crop damage than the correspond-
ing thiocarbamates (Table l) (18,20). This suggests that the sulfoxide
metabolites may be the actual herbicides. The sulfoxides may act by
carbamoylating a critical thiol site important in lipid biosynthesis (Fig.
8) (20,21,23).
Sensitive corn varieties are protected from thiocarbamate injury on
adding an "antidote", such as N,N-diallyl-2,2-dichloroacetamide. The
antidote elevates the level of GSH and increases the activity of the GSH S_-
transferase so the thiocarbamate sulfoxides are more readily detoxified by
carbamoylation of GSH (Fig. 8) (21-23). Many related antidotes for thio-
carbamate injury appear to act in the same way. Thus, the antidote builds
a resistance mechanism into susceptible varieties of corn.
167
-------
liver
microsomes
monooxygenase R /
NADPH K2
N-C
thiocarbainate
thiocarbamate sulfoxide
N-dealkyl deriv.
liver
soluble
I
GSH
GSH S-transferase
S-ma
N-dealkyl
mercapturic acid
t
mercapturic acid
N-C
GSH conjugate
V
I
I
R, .0
1%N-cf
^ S-cys
cysteine conjugate
9
"*OH
Fig. 7. Metabolism of thiocarbamates in rats. Abbreviations: R, and R =
alkyl or cycloalkyl; R^ = alkyl or substituted-benzyl; GSK= 2
glutathione; G, cys and ma = S-derivatives of GSH, cysteine and
N-acetyl cysteine (mercapturic acid), respectively; gly = N-
derivative of glycine (18-22)
Table 1. Herbicidal activity and crop injury with EPTC, butylate and
their sulfoxides when mixed with the soil before the seeds
were planted (18,20).
Plant
Weed species
3 Broadleafs
10 Broadleafs
5 Grasses
Crops
Corn
Sugarbeet
Field bean
Cotton
Herb.
rate,
kg/ha
0.5
1.7
0.5
3A
3.1*
3-^
3.^
EPTC
58
92
9^
70a
98
10
™~
Injury
EPTC
sulfoxide
90
98
89
Oa
99
0
— *"
rating, ave.
Butylate
23
55
56
0
20
80
40
%
Butylate
sulfoxide
68
99
98
0
90
20
100
a susceptible corn variety, the EPTC injury rating was °ik and 100%
at 6.U and 27 kg/ha, respectively, whereas no injury resulted with these
rates of EPTC sulfoxide.
168
-------
R ^0 , . R, .0 corn Rn v ,0
Al\ ^ plants^ 1\ 4 y 1s *
R "N"CNS-Ro ^Rg^'^S-IL GSH GSH £!- Rg^'^S-G
2 J 0 transferase
herbicide y active- 4* •f detoxification
precursor / herbicide | product
Plants
sensitive -
"antidotal
S-carbamoyl derivative action"
I corn
a>-<
R2 S-cys
of thlol site important precursors detoxification
m lipid biosynthesis ^ corn rQduct
Fig. 8. Metabolism of thiocarbamates in plants and the action of
dichloroacetamide "antidotes" in corn (18,20-23)
ACKNOWLEDGMENT
These studies were supported in part by the National Institutes of
Health (Grant 2 P01 ESOOOl|9).
REFERENCES
1. Yamamoto, I. and J. E. Casida. 1966. 0-Demethyl pyrethrin II analogs
from oxidation of pyrethrin I, allethrin, dimethrin and phthalthrin
by a house fly enzyme system. J. Econ. Entomol. 59; 15^2-15*4-3.
2. Tsukamoto, M. and J. E. Casida. 19&7- Metabolism of methylcarbamate
insecticides by the NADHU-requiring enzyme system from house flies.
Nature 213:^9-51.
3. Yamamoto, I., E. C. Kimmel and J. E. Casida. 1969. Oxidative
metabolism of pyrethroids in house flies. J. Agr. Food Chem. 17:
1227-1236.
h. Casida, J. E., E. C. Kimmel, M. Elliott and N. F. Janes. 1971.
Oxidative metabolism of pyrethrins in mammals. Nature 230:326-327.
5. Yamamoto, I., M. Elliott and J. E. Casida. 1971. The metabolic fate
of pyrethrin I, pyrethrin II, and allethrin. Bull. World Health
Organ. Mi:3*4-7-3^8.
6. Elliott, M., N. F. Janes, E. C. Kimmel and J. E. Casida. 1971.
Mammalian metabolites of pyrethroids. In Insecticides (A. S.
Tahori, Ed.), Gordon and-Breach, New York, pp. 1U1-162.
7. Elliott, M., N. F. Janes, E. C. Kimmel and J. E. Casida. 1972.
Metabolic fate of pyrethrin I, pyrethrin II, and allethrin following
oral administration to rats. J. Agr. Food Chem. 20:300-313.
8. Casida, J. E. 1973- Biochemistry of the pyrethrins. In fyrethrum
the Natural Insecticide (J. E. Casida, Ed.), Academic Press, New
York, Chap. 5, pp. 101-120.
9. Abernathy, C. 0. and J. E. Casida. 1973. Pyrethroid insecticides:
esterase cleavage in relation to selective toxicity. Science 179:
1235-1236.
169
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10. Abernathy, C. 0., K. Ueda, J. L. Engel, L. C. Gaughan and J. E.
Casida. 1973- Substrate-specificity and toxicological significance
of pyrethroid-hydrolyzing esterases of mouse liver microsomes.
Pestic. Biochem. Physiol. £: 300-311.
11. Jao, L. T. and J. E. Casida. 197^. Insect pyrethroid-hydrolyzing
esterases. Pestic. Biochem. Physiol. k:k65-k72.
12. Ueda, K., L. C. Gaughan and J. E. Casida. 1975- Metabolism of four
resmethrin isomers by liver microsomes. Pestic. Biochem.
Physiol. £:280-29U.
13. Casida, J. E., K. Ueda, L. C. Gaughan, L. T. Jao and D. M. Soderlund.
1975/1976. Structure-biodegradability relationships in pyrethroid
insecticides. Arch. Environ. Contam. Toxicol. 3_:^91-500.
lU. Soderlund, D. M. and J. E. Casida. 1977. Effects of pyrethroid
structure on rates of hydrolysis and oxidation by mouse liver
microsomal enzymes. Pestic. Biochem. Physiol. 6: in press.
15. Elliott, M., N. F. Janes, D. A. Pulman, L. C. Gaughan, T. Unai and
J. E. Casida. 1976. Radiosynthesis and metabolism in rats of the
[IE]isomers of the insecticide permethrin. J. Agr. Food Chem. 2k:
270-276. '
16. Gaughan, L. C., T. Unai and J. E. Casida. 1977. Permethrin metabolism
in rats. J. Agr. Food Chem. 25: in press.
17. Soderlund, D. M. and J. E. Casida. 1977. Stereochemical relationships
in pyrethroid metabolism. Amer. Chem. Soc. Symp. Ser.,in press.
18. Casida, J. E., R. A. Gray and H. Tilles. 197^." Thiocarbamate
sulfoxides: potent, selective and biodegradable herbicides. Science
18^:573-57^.
19. Casida, J. E., E. C. Kimmel, H. Ohkawa and R. Ohkawa. 1975.
Sulfoxidation of thiocarbamate herbicides and metabolism of thio-
carbamate sulf oxides in living mice and liver enzyme systems.
Pestic. Biochem. Physiol. £:1-11.
20. Casida, J. E., E. C. Kimmel, A. Lay, H. Ohkawa, J. E. Rodebush, R. A.
Gray and H. Tilles. 1975- Thiocarbamate sulfoxide herbicides.
Environ. Qual. Saf., Suppl. Vol. 3_: 675-679.
21. Lay, M-M., J. P. Hubbell and J. E. Casida. 1975. Dichloroacetamide
antidotes for thiocarbamate herbicides: mode of action. Science
189:287-289.
22. Hubbell, J. P. and J. E. Casida. 1977. Metabolic fate of the N,N-
dialkylcarbamoyl moiety of thiocarbamate herbicides in rats and"
corn. J. Agr. Food Chem. 25_; in press.
23. Lay, M-M. and J. E. Casida. 1976. Dichloroacetamide antidotes
enhance thiocarbamate sulfoxide detoxification by elevating corn
root glutathione content and glutathione £3-transferase activity.
Pestic. Biochem. Physiol. 6:
170
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BASIC THEMDS AND RESULTS
IN TEE STUDY OP PESTICIDE
TOXICOLOGY
Professor Tu.S.Kagan
(Research Institute of hygiene and toxicology of pesticides,
polymers and plastics . Kiev)
The discovery of chemical means of protection of plants against
pests and plant diseases,-pesticides, is an outstanding achievement
of contemporary science. Pesticides hold an important part in. tue
reduction of harvest losses. Along with it pesticides possess
certain qualities which present potential dangers for public heslttv
Of these mention should be primarily made of the high biological
activity of pesticides, the ability to survive in the environment
for lengthy periods, to accumulate in foodstuffs. The distribution
of pesticides on huge territories, penetration into soil, water
reservoirs, plants and animals create real conditions for the pene-
tration of these agents into the human organism.
The above listed features of pesticides make it necessary -:*
the hygienic and toxicological estimation of them to take into
account all the consequencies which may arise from raei. use-
The adverse effect of pesticides may develop in various direct-
ions. Tbey m«y De tke causes of acute poisoning. 34 thousand cases
171
-------
of acute poisoning with pesticides have been described in world
literature (1). Poisoning can be prevented by correct organization
of work, adherence to cautionary measures. It is much more difficult
to prevent chronic poisoning. Of great danger in this respect are
stable pesticides, especially chloroorganic compounds. It is well
known that mar-y chemical substance** passirg to the organism for
long periods in small doses may not induce clearly expressed signs
of poisoning. However, they can affect the imnmnobidlogieai reacti-
vity of the organism, reduce its resistivity to the effect of
be
various pathogenic factors. And this should'v/also taken into account
in estimating pesticides. Finally, chemical substances may contribute
to the appearance of a number of pathologic processes which are
not confined to the corcept of "intoxication** but which in their
after-effects may be much more serious than intoxication. The
question is about the appearance of allergic states, malignant
growth, about the mutagenous, teratogenic, embryotoxic and gonado-
toxic effect of chemical substances. These problems must also be
studied in examining pesticides*
One of the main problems of toxicology is to obtain data concern
ing toxicity and other noxious properties of pesticides prior to the!
i.itroriuction into practice. This principle is fully realized in
che USSR. No substance is allowed to be used as a pesticide without
preliminary studies* following which it can be sunctioned to use
by the General Sanitary and Epidemiologic Board of the Ministry of
Health of the USSR.
172
-------
The following measures are used to accelerate toxicologic
studies: (a) carrying out the research in stages,(b) compulsory
experimental to Ecological and hygienic examinations, (c) a
of criteria are given required for toxicologies! examinations ana
hygienic standardization of preparations,(d) concrete methods of
analysis are recommended. The stage approach to the examinations
enables the decision to be made at the very beginning about in-
exp*^iency of the further analysis of a substance in case of its
high toxicity. Thus highly toxic organophosphorous pesticides as
tetraethylpyropLosphate (TEPP1). thymet, M-74-, chlorinated hydro-
eiu'bonatos of the d^ne synthesis (dildrSn, endr in, i sods in and
many others). In case of a favourable appraisal of the preparation
at the second stage examinations are made aimed at the substantu-
ation of limiting concentrations in the working zone air, atmospheric
air, foodstuffs and in water, the working conditions during pesti-
cide tests in agriculture are studied and prophylactic measures
are worked out. If a decision is made to produce the new pesticide
commercially, then the physiologic and biochemical mechanisms of
its action are studied fundamentally and spec7tic measures of prophy-
laxis and therapy of poisoning are elaborated.
The unification of the research program aimed at solving
specific problems associated with toxicological appraisal and hygi-
enic standardization of new chemical substances, the strict stage-
by-stage approach to the research makes it possible not orly to
to
solve practical problems in short periods but alsoveontriimte to
the accumulation of data on certain theoretical questions.
173
-------
Now more than 900 chemical compounds are used in the world
as pesticides of which about 230 are either used or tested in the
USSR; however, since some of them contain one and the same active
agents, there are much less individual chemical substances of this
kind (2). The comparison of the range of pesticides in use fo a
number of yaars bears testimony to a rapid increase in their nomen-
clature connected with the growing stability of pests to certain
preparations, necessity of their replacement and alteration, with
the trend to use pes-icides selectively affecting noricus objects
without injuring the useful ones, having low toricity for people
and animals, and with a number of other reasons (3-7).
The present report deals only with some most important
in the toxicological study of pesticides and considers fi
obtained in recent years which characterise the potential
of pesticides related to the two most widespread classes,
chlororganic and organophosphoroua compounds; due attention is also
given to the ways of preventing their unfavourable effect on public
healf .
It has been proved beyond doubt that DDT is accumulating in
the adipose tissue of most people of the world.
It has been established that along with DDT other chlororganic
pesticides such as Lindane, dieldrin, heptachlor are also accumulating
in the adipose tissue but their content is considerably lower than
DDT and commonly does not exceed 0.1-0.3 Eg/kg. Different contents
of DDT in foodstuffs, peculiarities of food rations (con-
sumption of meat, dairy products, etc.) are perhaps the main reason
174
-------
for different contents of the insecticide in the adipose tissue of
people (8-12).
The question about the carriage of DDT and other chlororganic
pesticides is no longer a subject for debate. The harmfulness of
this carriage is still under discussion. In recent years new experi-
mental and clinical findings have been obtained bearing evidence
to harmfulness of the carriage of chlororganic compounds (13-32).
The effect of small doses of DDT to the functional state and
structure of liver has been established (22). Prolonged administra-
tion of DDT to laboratory animals increases their sensitivity to
coronary spastic agents (pituitrin), accelerates the development
of experimental cholecteric atherosclerosis in rabbits (23-25).
It ^as been proved that DDT affects the intensity ol energy meta-
bolism, the fixation and release of serotonin, the content of pyrJ-dUv
nucleotides in aniraal tissues, the permeability of cell membranes,
the immunoheniatologic indices (27-32)*
In the general appraisal of the potential danger of DDT due
attention should be paid to the effect of small doses of DDT on the
endocrine system of animals, and, which is of particular importance»
to the gonadotoxic, mutagenous and carcinogenic effect of DDT
(33-36). In one of the experiments (34) five generations of inbred
mice were kept on a ration with the addition of DDT, and starting
with the second generation the rate of malignant tumors (carcinoma
and sarcoma) increased (28.7J& cases as against 3.2% in the controls),
and she number of leukt^aia cases increased, starting from the third
generation. The carcinogenic effect of DDT has been confirmed "oy
the study of V.S.Turussov (37).
175
-------
All the mentioned information related to the harmfulness of
DDT makes it necessary to speed up the resaarch work aimed at the
replacement of it and other stable chlororganic pesticides in agri-
culture.
The existence of a number of adverse properties in chlororganic
pesticidos has led to a vast development of toxicolo* .ioal researsi
of less sta'le and less cumulative organophoanhoro^a compounds.
Their high torlcity for people and warm-blooded animals was the
principal obstacle to the wide use of such compounds. Information,
related to the acute poisoning of people by compounds of this group
has been reported and is being published (1, 58, 39). The danger
of chronic poisoning byOKJ- has been studied to a considerably lea-
extent r (40, 41).
A number of efficient substances have been found among OFC with
medium (chlorophos, carbophos, threechlormethaphos-3t aethyl-nitro-
phos, methathion, bytex, dibrom, amiphos, cyanox and others; an.: L ov
(sajphoa, gar dona, bromophos, abat, valexon, demuphos) ton city
for warm-blooded animals and man. The feasibility of acute poisonii^
from these preparations is considerably less in comparison
with mercaptophos and thiophos used before, as well as with methyl-
mere aptophos, methaphos, phosphamide and others still used in
agriculture, ^oxidynamics of these compounds is being studied it
present.
In recent years information has been reported related to the
possibility of tae injurious effect of organophosphorous prepara-
tions on the fetus and fetation. It has been established that para-
i,lion, a>thylparathion, dichlophos, diazinon, and TEPF penetrate the
176
-------
placenta of rats and cause a frequent resorption of the fetus, a re-
duction in the fetus weight and the weight of placenta, as well as
congenital malformation. Certain preparations (parathion, diazinon,
TEPP) brought about a resorption of the fetus when administered in
doses which did not cause intoxication of the pregnant animals (42-
4-7).
The embryotoxic effect of phthalophos has been established also
with comparatively low dosage (administered in pregnancy every other
day in 0.3 mr/kg - 1/500 part of the lethal dose) (48). A distinct
dependence of the pronounced character of the phthalophos embryoto-
xic properties on the rate of daily dose has been found. A single
administration of higher doses of phthalophoc may bring about a te-
ratogenic effect (flipper-like extremities,strangulation of the
pelvic girdle, hydrocephalus, hydronephrosis). When phthalophos is
administered to pregnant rats, it can be found together with its
metabolite (phthalimide) in small concentrations in the uterus,
placenta and fetus tissues. It has been established that the embryo-
toxic effect also manifests itself due to the introduction of pnfcha-
limide which is the phthalophos metabolite (48).
On the basis of the finding it could be assumed that the enbryo-
tosic effect is associated not with the organophosphorous compound
itself but with the phthalimidic part of its molecule which also
enters into the composition of the well known thalidomine teratogen.
However, recently convincing facts have been obtained about the
availability og griadotoxic, embryotosic and teratogenic properties
in chlorop'ios and methylmercaptophos in the absence of the phthali-
177
-------
aide group (44-4-7,4-9). 1. s..bstantial. change in the fertility of :rats
has been discovered caused "by the inhalation of nethyl-iaercaptophos.
It has been ascertained that methylmercaptophos in small doses
enhances the motor activity of the uterus of pregnant animals (4$),
A report has been appreared about the carcinogenic effect of
chlorophos which was revealed in the experiment on the Vistar rats
and on mice of the AB strain (50). The authors associate this effect
with alkylic properties in chlorophos. At present the mutagenous
properties of organophosphorous pesticides are being studied.
All those findings indicate that the information concerning the
acute toxicity of orgahophosphorous pesticides is insufficient for
their appraisal. An all-round examination is required of the pesticide*
to rule out their adverse effect on the progeny and other remote after*
effects.
A new approach to the directional synthesis of organophosphorous
pesticides and acaricides has been realized in the laboratory of
Academician H.I. Kabachnik(5I-54)« Various OPC containing radicals of
natural axoinoacids in the molecule have been synthesized. It was
suggested that the presence in the OPC molecule of amino acid radicals
could affect the character and spead of inhibition of choline-sterases
of warm-blooded animals and insects. The structure of the amino acid
can also have influence on the interaction of OPC with enzymes,
providing for their detoxication,particularly, with carboxyl-esterases
and peptidases. These theoretical assumptions have been justified.
A number of organophosphorous pesticides, low-toxic for warm-blooded
animals and possessing a selective insecticidal and acaricidal effect,
178
-------
have been synthesized. The examination of these compounds has made
it possible to ascertain the relation between the features of their
structure, character and the rate of metabolism,
by the interaction with choiinesterase to clarify the role of
steric factors in the reaction with carboxylesterases. It is
important that these compounds disintegrate into natural metabolits
which lessens the likelyhood of the appearance of unfavourable
after-effects.
New results have teen obtained in the study of the mechanism
of action of OPC (55-57) and of cholinesterase reactivators which
can be used as antidotes of organophosphorous pesticides (56-63).
Combining histochemical, electronic microscopy and electro-
physiological (micropotentials) methods of analysis, we succeeded
in proving that not only the activation of cholinesterase but also
the influence of the reactivators on the functioning of pre- and
postsynoptic formations are of importance in the mechanism of ac-
tion of OPC and diproxime (TMB-4) (59, 65).
Proceed-'-^g from the hypothesis that reactivators close in
structure to acstylcholine can better reactivate cholinesterase,
we synthesized a series of S-diethylaminoethyl ethers of tiohydro-
oacirane acids some of which turned to be active antidotes of organo-
phosphorous pesticides (60-63).
In the USSR there is an orderly system of the toxicohygieiiic
appraisal of pesticides which enables both the problems of pesticide
introduction into farming practice and of hygj-jnic regulation
to be solved in clue time. Rules are laldi down for the sequence
179
-------
and periods of examining the toxic properties of pesticides enter-
ing the organism by various routes, for the conditions and duration
of experiments on the study of the cumulative effect of substances,
for the duration of chronic experiments! for the conditions of
experiments aimed at revealing the sonodotoxic, embryotoxic, teratc—
genie, mutagenic and allergenic properties of pesticides. The analy-
sis of pesticides should be carried out in such a manner as to
establish their potential and real dangers which may be dependent
not only on the toxic properties, bat also on the ability to cause
any pathogenic effect. Since it takes much work and time to reveal
allergenic, mutagenic, gonadotoxic, embryotoxic, teratogenic and
particularly blastomogenic properties in substances, new pesticides
should be analyzed in stages.
If a preparation is recommended for pilot-plant production,
toxico-hygienic studies must be carried out in full scope and end
in the establishment of hygienic standards and norms for the content
of pesticides in the environmental objects (working zone air, atmos-
pheric air, foodstuffs, water of water reservoirs).
The hygienic standards must guarantee against any adverse
effect of pesticides on the health of man, and therefore in establi-
shing the standards the possible remote unfavourable after-effects
must be taken into account.
For practical decisions about the possibility and scope of use
of pesticides, as well as about their hygienic standardization
of much importance is the elaboration of quantitative criteria of
on the basis of which the pesticide can be related ID
180
-------
one or another group of hygienic classification, and the hygienic
standards can be determined (6).
It should be stressed that there is an ever growing trend to
estimate the connection of the revealed changes with the duration
of the effect, to ascertain the probable threshold levels of the
effect of substances possessing a specific action or able to cause
remote after-effects. Along with the quantitative aspect of the
problem due attention is given to qualitative aspects such as the
study of biochemical and structural changes which determine the
development of pathological processes.
as
'Je consider Kthe most important task in the study of the
biological action of pesticides the development of the theory of
predicting the pathology which may be caused by them, and the
.jovelopr.er.t, of criteria of their potential and real danger. For this
it is necessary to correla£eVaata obtained in experiments with
laboratory aniaals in comparatively short-term studies with the
results of long-term observations during the entire life of the
animal, as well as during the life of several generations. Of great
importance is the comparison of the results of experimental and
toxicologies! examinations wiva the data of hygienic and social-
hygienic studies.
References
I, v.l.Polchenko. In: Hygiene of UsefToxicology of Pesticides and.
Clinical Picture of Poisoning; Issue 6, Kiev, published, by
7NIIGINTQX,1968,61.
181
-------
2. N.N.Melnikov. Modern trends' in the development of production and
application of pesticides. M. , published by VINITI,I970.
5. N.K.Melnikov. J. of USSH Mendeleev Chei ical Society,I968,I2,248.
4, L.I.Medved» In: Hygiene of Use, Toxicology of Pesticides and
Clinic*! Picture of Poisoning. Issue 8, Kiev,published by
VHIIGOTOK, I970,p. 5-
5. TtuS.Kagan. Ibidem, p. 18.
6. L.I.Medved, Yu.S.Zagan, E.I.Spynu. J. of USSR Mendeleev Chenical
Society, 1968 ,!£, 263.
7. K.I.Kabachnik. Ibidem, 1968, 1^, 242.
8. I.E. Dale, U.F. Cope land, W.T.Hayes. Bull. World Health Org. ,1965,
9. E.Engst, B.Znoll. Phaimazie, 1969.24.673.
lO.W.F.Durbman. Ann.K.T. Acad. Sci. ,1969,160 ,183.
II.W. J.Hayes et al. Arch. Env. Health, 1971,22, 119.
12.M.Wacserman et al. J.Afr.lted. .1970.44.646.
I3.V.E.Iorubutova, L.P.Kondratieva. In: Hygiene and Toxicology of
Pesticides and Clinical Picture of Poisoning. Kiev, Zdorovie
(health), 1965, p. 184.
I4.G.V.Gracheva. Nutrition Problems, 1970,2^,128.
I5.L.P.Vaskovskaya. In: Hygiene of Use .Toxicology of Pescidies and
Cliiical Picture of Poisoning. Issue 7, Kiev, published by
VNIIGINTOK , 1969 ,p .496
I6»L.I.liedved. In: Problems of Hygiene and Toxicology of Pesticidos,
K.Medicina publish. ,I970,p. 75.
Moldavian Health Sei"/ices,I970,2_,2.
182
-------
Ic. L.I.Komarova. In:Hygiene of Use,Toxicology of Pesticides and
Clinical Picture of Poisoning:. Issue 8,Kiev,published by
VHIIGINTOX,I970,p.62.
19. L.I.Komarova, L.F.Vaskovskaya. Ibidem,Issue 6,I%8,p.62,
20. 0.:,r.Nemirovskaya. In: Problems of Sanitary Propection of Environ-
mert,Hygiene of Work and Prophylaxis of Diseases. L.,Medicina,
I970,p.90.
21. G.V.Gracheva. In: Factors of the Environment and their impact on
Public Health. Issue I,Kiev,ZdorovielI969,p.I25.
22. Yu.S.Kagan, G.A.Rodionov, O.M.Kilagin, L.Tu.Voproninfr. In:Hygiene
of Use,Toxicology of Pesticides and Clinical Picture of Poisoning
Issue 8,£Lev,published by VNIIPGINrQXtI970tp.69.
. A.iI.Lukaneva,O.P.Petrovskaya, S.I.Ivanova. Ibidem,Issue 5,I967f
p.263.
. A.M.Lukaneva. Ibidem,Issue 6,1968,p.73I.
25. A.M.Lukaneva, S.I.Ibanova. Ibidem,Issue 8,1970,p.6J.
26. Yu.S.Zagan. In collection:Transactions of the VIII-th Congress
of Hygienists of the Ukr.SSR,Kiev,Zdorovie,I97IfP«205.
27. U.A.Kuzniiaskaya. In: Hygiene of Use,Toxicology of Pescides and
Clinical Picture of Poisoning. Issue 8,Kiev,published by
VNIIGINTQX,I970,p.IOI.
23* B.I.Khaikina, V.F.Shilina. Ibidem,p.I0i.
29. U»A.Kuzminskaya,I«I.Pavlova. Ibidem,p.110.
JO. 8»I.Fudel-Ossipova,S.D.Kovtun, A.I.Sokur. Ibidem,Issue 6,1968,
p.707.
51. A.I.Sokur.Ibidem. Issue 9,1971,p.2IJ.
183
-------
32. jS.M.Semencheve. rbidem,Issue
33. U.N.Rybakova. Problems of Nitrition.1967,26,9-
35, A.Tarjan, T.Zerery. Pood Cosnet.Toxicol.,l9&9t2i2I5.
56. D.S.ilarkarian. Geneticsfl966,I,I3I.
37. V.S.Turussov. Problems of Oncology,I975f2I,No.12,p.37-38.
33. Yu.S.Kagan. Toxicology of Organophosphorous Pesticides and
Hygiene of Work in Their Application. M.,Medgiz Publ.,1963.
39. S.A.Luzhni^ov, Y.A.Dagsev. Soviet Medicine,II,76,196^-.
40. I.S.Paerman. Therapeutic Archives,1965.37tNo.3.31.
4I.I.S.Paermant I.D.Volkova,3.S.Parfenova. Ibidem.1969.41.No.12.23.
42. R.D.Kimbrogh. T.B.Gaines. Arch.Env.Health,1968,16,805.
43. R.D.Kimbrough, T.B.Gaines. Toxicol.Appl.Pharmar I970,I7»679.
^4. V.A.Gofmekler, N.N.Pushkina, G.N.Zlevtshova. ^ygiene and Sanitary
1963,No.7,96.
45. V.A.Gofmekler. Ibidem,I%9,No.8,47.
46. Z.S.Saraymanova. Effect of some toxic chemicals on genital systen
Abstract of c thesis,Tashkent Med.Inst.,I97I«
47. Z.S.Saraymanova. Kh.S.Umarova. In: Urgent Problems of Obstetrics
and Gynecology,Tashkent,Uedicina,I969tP.169.
48, V.M.Voronina.In: 3ygiene of Use,Toxicology of Pesticides and
Clinical ^Picture of Poisoning. Issue 9>Eiev> published by
VIJIIGINTOXfI97I,p.254.
49. E.K.Levkovskaya. In: Hygiene of Use.Toxicology of Pesticides and
Clinical Picture of Poisoning. Issue 9,Eiev, published by
VNIIGINTQX,I97I,p.I80.
50. W.Gibel, Kh.Lohs, Arch.f.Geschwulst forsch 37fI968,303.
184
-------
51. T.A.Mastryukova,A.3.Shipov, E.B.Gorbenko et al. News of USSR
Academy of Science,Chemical series, 1968,No.9,204-2.
52. T. A. Mastryuk ova, A. E.Shipov, E.B.Gorbenko et al. I"bidera,I97I,No.9,
2003.
53. E,A.Brshova, Comparative Toxicological Analysis of NCT Organopho-
sphorous Insecticides and Acaricides Containing Amino Acid Radi-
cals. Abstract of a thesis,Kiev Inst.of Pharm. and Toxicol.,1972.
54. M.I.Kabachnik. ,Yu.S.Kagan,W.A.Klisenko et al. ImHiarm. • ari Toxic
logy, Issue 8fKiev,Zdorovie,1973,p.118.
55. M.I.Kabachnik, A.P.Brestkin, H.Ta.Mikhelson. Mechanism of Physio-
logical Action of Organophosphorous Compounds. IX-th Mendeleev
Congress on General and Applied Chemistry. M,Nauka,I965.
56. M.I.Kabachnik. News of USSR Academy of Science,1968,5,86.
57* A.ft.Brestkin. Ins Chemistry and Application of Organophosphorous
Compounds,M.,Nauka,I972,p.322.
58. lh.D.Dikovsky. Experimental Study of the Mechanism of Ac ion of
some Reactivators of CLolinesterase in DDVP Poisoning. Abstract
of a theses,Kiev Medical Inet.,1971.
59. Kh.D.Dikovsky, Yu.S.Kagan, S.D.Kovtun et al. Fiziologichniy
Zhurnal,l973fI9,3IO.
60. V.E.Krivenchuk, L.I.Brizgailo. Im fyglene of Use,Toxicology of
Pesticides and Clinical Picture of Poisoning. Issue 8,Kiev,
published by VNIIGINTOX,I968,p.438.
61. V.E.Krivenchuk, V.E.Petrunkin. Author's Certificate of USSR,1970,
No.287931t Bulletin of Inventions No.36,27,1970.
185
-------
62. Tu,S.Kagan,L.P.Danilenko, V.I.Krivenchuk, V.E.Petrunkin. Ini
Modern Fharmocological Problems, Kiev, Zdorovie,I97Ifp.I09.
6J. lU.S.Kagan et al.,Ph«rm. and ToxicolrI975fNo.3tp.294-297.
186
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METABOLISM AND PERSISTENCE OF PESTICIDES AND
OTHER XENOBIOTIC CHEMICALS IN FISH
John J. Lech, Ph.D.
Medical College of Wisconsin
561 North 15th Street
Milwaukee, Wisconsin 53233
Although studies in the early 1960's had indicated that fish do not
metabolize drugs or foreign compounds to any extent, several investigators
have demonstrated the presence of microsomal mixed function oxidases and
conjugating enzymes in livers from several species of fish (1-3). The
results of these investigations have indicated that many species are able to
oxidize, dealkylate, reduce and conjugate foreign chemicals in vitro.
Based on these studies, the level of hepatic microsomal enzymes in many
species of fish appear to be lower than that observed in mammals, but
quantitative in vivo studies to substantiate this point have yet to appear.
Even though biotransformation products can be formed enzymatically using
fish liver preparations in_ vitro, it is difficult to predict from an in_
vitro study which, if any, such products will be formed during in vivo
exposures. In a study involving the biotransformation of the lampricide 3-
trifluoromethyl-4-nitrophenol (TFM) in rainbow trout, the formation of 3-
trifluoromethyl-4-aminophenol and N-acetyl-S-trifluoromethyl-H-aminophenol
was demonstrated using liver preparations in vitro (4-). However, the only
detectable metabolite formed in_ vivo during exposure to TFM was 3-trifluoro-
methyl-4-nitrophenol glucuronide which was excreted to a large extent in
bile (5). The disposition of two other phenolic compounds (Bayer 73) and
pentachlorophenol (PCP), have been studied in rainbow trout, and the major
metabolite of both of these compounds appears to be the glucuronide conju-
gate, although conjugation of pentachlorophenol with sulfate has been
reported in other species (6,7).
Studies of the fate of 1-naphthyl-N-methyl carbamate (Carbaryl) in
rainbow trout have indicated that a major pathway of metabolism involves
hydrolysis to 1-naphthol and conjugation of naphthol with glucuronic acid
(8). Esters of the herbicide 2,4D undergo hydrolysis to the free acid in
several species of fish (9,10).
Since enhanced excretion appears to be the consequence of conjugation
of compounds possessing functional groups such as OH, NH2 and COOH, with
glucuronic acid, of great interest relevant to residue persistence is the
oxidation of more non-polar compounds which do not have these groups such as
187
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the polycyclic aromatic hydrocarbons found in crude oils and the poly-
chlorinated biphenyls (PCB's). Naphthalene and 3,4- benz;opyrene have been
shown to be oxidized to more polar compounds by several species of marine
fish, and these metabolites appear to be excreted in urine and bile (11).
The polychlorinated biphenyls are highly persistent contaminants and
residues of these compounds in fish have presented a major problem. Most
studies have indicated very low rates of metabolism of the PCB's in fish
and residue persistence is measured in terms of months or years (12,13).
Laboratory studies concerning biotransformation and persistence of
xenobiotics in fish present some major obstacles when compared to mammalian
investigations, and techniques which are directly relevant to the natural
environment have been slow in development. Even relatively simple in vitro
studies using liver preparations must be approached with an appreciation of
the differences in optimal assay temperature (.2) which exists among
different species of fish as opposed to mammals.
Realizing that the tasks of evaluating a multitude of chemicals in many
species of fish would be an enormous undertaking, attempts have been made to
develop predictive methods for certain chemicals which have a high bio-
accumulation and persistence potential. By measuring the rate constants for
uptake and elimination in a constant flow exposure system, a theoretical
bioconcentration factor can be calculated (14). This factor has been shown
to be directly related to the partition coefficients of the compounds
studied, and in a limited series, the calculated and experimental values
appear to agree quite well(14-).
Besides serving to clarify the relationship of biotransformation to the
pharmacology and persistence of foreign chemicals in fish, information
gleaned from these studies has some immediate practical applications. In
many monitoring programs, analytical procedures are designed to determine
residues of only the particular chemical under investigation and not its
metabolites. In some instances this can be quite misleading. Muscle
sampled from pinfish which were exposed to malathion for 24 hours contained
little or no malathion but did have considerable concentrations of the
monocarboxylic acid metabolite of malathion (15). Similar findings have
been reported for esters of 2,4D (9). Even though the original chemicals
were not detectable, the presence of metabolites revealed that the fish were
exposed to the parent compounds, and this information in itself may be one
of the more important considerations.
A possible application of studies concerning the biotransformation and
biliary excretion of a number of xenobiotic chemicals is the use of fish bile
sampling as an aid in monitoring for certain chemicals (16). In this study
it was shown that many of the more water soluble compounds which do not have
a high bioconcentration potential in tissues such as muscle are excreted in
a highly concentrated form in bile. Sampling of bile from caged or wild
fish in suspect areas may provide a -convenient means of enhancing monitoring
programs.
188
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REFERENCES
1. Adamson, R. H, Fed. Proc. 26: 1047, 1967.
2. Dewaide, J. H. in Metabolism of Xenobiotics. Drukkerji Leijn,
Nijmegen, 1971.
3. Pohl, R. J., Bend, J. R., Guarino, A. M. and Fouts, J. R.
Drug Metab. and Disp. 2_: 545-555, 1974.
4. Lech, J. J. and Costrini, C. N. Comp. Gen. Pharmacol. 3: 160,
1972. ' ~
5. Lech, J. J. Toxicol. Appl. Pharmacol. 24: 114, 1973.
6. Statham. C. N. and Lech, J. J. J. Fish. Res. Bd. Can. 32;
515, 1975.
7. Akitake, H. and Kobayashi, K. Bull. Jap. Soc. Sci. Fish
41: 321, 1975.
8. Statham. C. N., Pepple, S. and Lech, J. J. Drug Metab. and Disp.
_3: 400, 1975.
9. Rogers, C. A. and Stalling, D. L. Weed Sci. 20^: 101, 1972.
10. Statham, C. N. and Lech, J. J. Toxicol. Appl. Pharmacol. 36:
281, 1976.
11. Lee, R. F., Sauerheber, R. and Dobbs, G. H. Marine Biol. 17:
201, 1972.
12. Lieb, A. J., Bills, D. D. and Sinnhuber, R. 0. J. Agr. Food
Chem. 22: 638, 1974.
13. Guiney, P. D., Peterson, R. E., Melancon, M. J. and Lech, J. J.
Toxicol. Appl. Pharmacol. (In Press).
14. Branson, D.R. Symposium on Structure- Activity Correlations in
Studies of Toxicity and Bioconcentrvvtion with Aquatic Organisms.
International Joint Commission, Canadian Center for Inland Waters,
1975, page 99.
15. Cook, G. H. and Moore, J. C. J. Agr. Food. Chem. 24: 631, 1976.
16. Statham, C.N., Melancon, M. J. and Lech, J. J. Science, 193: 680,1976.
189
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Pesticide Movement in the Organism of Farm Animals
G. A. Talanov
Research Institute of Veterinary Sanitation, Moscow
I. Pesticides may enter the organism of farm animals in feeds,
water, air or through the skin when treating the animals to protect
them against ectoparasites. However, only oral and cutaneous path-
ways are of practical importance,
2.Further fate of pesticides depends on the properties of
chemicals, ways of their entering the organism, and animal species*
Persistent organochlorine pesticides (DDT, HCCH, aldrin, heptachlo-
rine, etc*) are resistant to the alimentary canal microorganisms
and ferments, have poor water solubility and, therefore, slow ex-
cretion from the organism in urine, and, being lipoidophyllic, may
accumulate in adipose tissue. Organophosphorus and carbamate insec-
ticides, herbicides-derivatives of phenoxy-acetic acid, series of
triazines, urea, and many other pesticides are mostly decomposed
by the alimentary canal microbes and ferments of the organism when
entering through mouth. Polarity of these compounds is considerab-
ly higher than that of organochlorine pesticides and, therefore,
they may be better excreted through urinary tract. In this connec-
tion, degree of material cumulation of organophosphoms and other
190
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similar pesticides in the organism of farm animals, their excretion
in milk and eggs when entering internally are hundred times lower
than that of organochlorine compounds similar to DDT. Thus, if the
coefficient of material cumulation "feed-fat" of various species
of animals ranges from 5 to 20 for DDT, and from 0.5 tol for gam-
mer—iscaer HCCH, it is less than 0.01 for one of the most stable
organophosphorus insecticides - trichlorometaphos-J. The level
of excretion, in milk for DDT and HCCH when entering internally
is 5-1095 of theresidual amount in feed and it is 100-200 times
lower for trichlorometaphos. Residues of organophosphorus and car-
hamate insecticides, herbicides, and fungicides, with the excep-
tion of mercuric compounds, in feeds for farm animals are of in-
significant practical importance and are not able to exert a ne-
gative influence on the sanitary quality of animal production.
Contamination of milk, meat, and eggs through feeds may mainly
occur at the expense of organochlorine insecticides, heavy metals,
PCB, arsenic, and other stable chemicals. This is confirmed by
the results of mimerious investigations of the animal production
samples carried out in the Soviet Union, the United States, and
other countries*
3* For ruminants (cattle and small cattle), decomposition of
pesticides entering through mouth may mainly occur at the expense
of the paunch microorganisms, whereas for poultry, the liver fer-
ments play a decisive role. This is confirmed by the difference
in the pathways of the p^-DDT metabolism. For ruminants, p,p'-
DDT mainly metabolizes to p,p*-DDD, This pathway is possible un-
191
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der the influence of anaerobes only. For poultry, most of the p,p' -
DDT converts to pfp'-DDE that is characteristic for the fermental
breakdown of this compound.
4, Penetration of nonpersistent pesticides in water is much
more hazardous from the toxicological and sanitary point of view.
For ruminantsttoxicants together with water enter directly abo-
masum avoiding paunch, then small intestines and blood. In this
case, hydrolyzing action of the paunch microbes is eliminated.
Therefore, different physiological effect and residual content
level in tissues and milk are observed when applying pesticides
in feed and water at the same doses,
5- Somewhat different regularities were found in the pesticide
behavior in the organism of farm animals under the external appli-
cation. Well known are the long-term retention of DDT, HCCH, chlo-
rinated terpenes, and other persistent pesticides in the organism
of animals and their excretion in milk and eggs when spraying cattle
and poultry. Therefore, organochlorine insecticides, with the ex-
ception of HCCH, are not used for the treatment of farm animals
in the Soviet Union, Organophosphorus compounds are Thinly used
for this purpose. However, many lipoidopbyllic Organophosphorus
compounds may be conserved in adipous tissue from 7 to 75 days un-
der cutaneous application depending on the sort of pesticide, type
of treatment, and species of animal. Most of the pesticides of this
group are excreted in milk and eggs in larger quantities than when
entering through mouth at the same doses. This appears to be ac-
counted for by the fact that Organophosphorus compounds may easily
192
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penetrate in blood through undamaged skin and are not subjected
to destructive action of the alimentary canal microbes, as it oc-
curs when chemicals enter through mouth. In this connection, the
necessity arises to investigate behavior in the organism of any
pesticide which is recommended for the external treatment of ani-
mals to establish regulations for its use.
6* Organochlorine insecticides are mainly concentrated in the
fat of animals as well as nonpolar organophosphorus compounds. Their
content in other tissues is considerably lower. Degree of pesticide
accumulation in fat and duration of their retention in tissues are
inversely proportional to their polarity. Thus, 5 days after a single
injection into sheep of diazinon (OfO-diethyl-0-(2-isopropil-4-me«»
thyl-6-pyramidil)thiophosphate), phtalophos (imidane), trichloro-
metaphos-2, gamma-isomer HCCH, and pp1 -DDT at the dose of 20 mgr
per kg of weight, the residual level wast 0.4-} 1.40} 1.60; 4,08,
and 18.8 mg/kg - in fat and O.Oi; 0.45; 0.40; 0,?8, and 0.56 mgr/ke-
in muscles, respectively.Therefore, the content of residual DDT
in fat was higher than that in muscles by a factor of 55, HCCH -
5.5, trichlormetaphos-3 - 4, phthalophos -5.1, and diazinon - 4.
This data also shows that there is no substantial difference in
residual contents of organophosphorus insecticides (phthalophos
and trichlorometaphos—5) and organochlorine compounds (HCCH and
DDT) in muscular tissue of sheep.
193
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MATHEMATICAL MODELING OF PESTICIDES IN THE ENVIRONMENT
James Hill IV*
United States Environmental Protection Agency
Several modeling and systems analysis techniques are particularly
applicable to the problems presented by pesticide chemicals.
Component modeling of the processes affecting pesticides is well
developed by comparison with our ability to coordinate these components in a
model of a whole environmental system. Current modeling of pesticides treats
their distribution as a transport phenomenon where the pesticide is associated
with air, water, or soil/sediment movement. Specific process components are
coupled to the transport model where they relate directly to the degradation,
transformation, or transport-media exchange of the pesticide. The chronic,
long-term effects and consequent ecosystem responses that are not represented
in these models are now recognized to be as important as the short-term acute
effects.
Total ecosystem models can be developed for pesticides; however, the data
required to support realistic simulations in models of this resolution are
prohibitive for a large number of pesticides. Linear approximations of total
ecosystem models, which represent all processes as pseudo first-order
processes, can be supported with considerably reduced data requirements and
provide a format for sensitivity and worst case analyses.
The problems of identification of indirect environmental effects and
evaluation of complex system interactions associated with pesticides can only
be resolved through co-evolution of laboratory, field, and modeling approaches
to these problems. The application of ecosystems theory, examining all the
aspects of stress, stability, energy fluxes, nutrient cycles, carbon
metabolism, and trophic structure in environmental systems, is emerging as one
of the modern approaches to the complex problems of chemical pollutants.
Although ecosystem models and analysis allow for evaluation of complex system
interactions and for quantification of indirect environmental effects, their
data requirements are prohibitive for application to most pesticides.
The developing theory of hierarchial models with nested levels of control
and interactions among subsystems has a potential application to the pesticide
problem. In applications of hierarchial modeling to pesticides in the
environment, subsystems of a hierarchial, ecological model that are affected
*Environmental Research Laboratory, United States Environmental Protection
Agency, College Station Road, Athens Georgia 30601.
194
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by the pesticide may behave without hierarchicalconstraint and the behavior of
constrained subsystems may be observed as indirect responses to the pesticide
in the context of higher level control and interaction. One of the problems
associated with this application of hierarchial modeling theory is that
environmental systems have a "closed causal structure."
Influence analysis provides quantitative measures of the organization of
system structure and may allow a complex ecosystem model to be reduced to a
minimal subset of aggregated components and condensed interactions such that
the behavior of the complex model is qualitatively preserved. If the reduced
model can be related to the constituents of a laboratory microcosm, then a
link between laboratory experiment and whole system behavior may be
established.
Research needs to be directed toward mathematical modeling that allows
translation of laboratory measurements of pesticide effects on growth,
physiology, and environmental interaction to field conditions. Thus, models
need to be developed that estimate whole system behavior based upon data
representing a limited set of component interactions. Hierarchical models with
constrained subsystems and homomorphic structures derived from influence
analysis may accomplish these goals in the near future.
REFERENCES
1. Crawford, N. H. and A. S. Donigian, Jr. 1973. Pesticide Transport and
Runoff Model for Agricultural Lands. U. S. Environmental Protection
Agency, Contract Number 68-01-0887.
2. Davidson, J. M., G. H. Brusewitz, D. R. Baker, and A. L. Wood. 1975.
Use of Soil Parameters for Describing Pesticide Movement Through Soils.
EPA-660/2-75-009, U. S. Environmental Protection Agency, Corvallis,
Oregon. 162 pp.
3. Donigian, A. S., Jr. and N. H. Crawford. 1976. Modeling Pesticides and
Nutrients on Agricultural Lands. EPA-600-76-043, U. S. Environmental
Protection Agency, Athens, Georgia. 318 pp.
4. Eberhardt, L. L., R. L. Meeks, and T. J. Peterle. 1971. Food Chain
Model for DDT Kinetics in a Freshwater Marsh. Nature. 230:60.
5. Finn, J. 1975. Measures of Ecosystem Structure and Function Derived
From Analysis of Flows. J. Theor. Biol. In press.
6. Gillett, J. W., J. Hill IV, A. W. Jarvinen, and W. P. Schoor. 1974. A
Conceptual Model for the Movement of Pesticides Through The Environment.
EPA-660/3-74-024, Government Printing Office. 79 pp.
7. Gillett, J. W. and J. Haefner. 1975. Mathematical Modeling of Pesticide
Fate. In: Substitute Chemical Program - The First Year of Progress. U.
S. Environmental Protection Agency, Washington, D. C. pp. 65-71.
195
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8. Goodman, E. D. 1975. Review of Research Plan for Whole Systems Model.
In: Substitute Chemical Program - The First Year of Progress. U. S.
Environmental Protection Agency, Washington, D. C. pp. 53-60.
9. Hannon, B. 1973. The Structure of Ecosystems. J. Theor. Biol. 41:535.
10. Harrison, H. L., 0. L. Loucks, J. W. Mitchell, D. F. Parkhurst, C. R.
Tracy, D. G. Walls, and V. J. Yannacone, Jr. 1970. Systems Studies of
DDT Transport. Science. 170:503.
11. Hill, J., IV. 1976. Influence: A Measure of Structural Organization of
Systems. PhD Dissertation. University of Georgia, Athens. 200 pp. In
preparation.
12. Hill, J., IV, H. P. Kollig, D. F. Paris, N. L. Wolfe, and R. G. Zepp.
1976. Dynamic Behavior of Vinyl Chloride in Aquatic Ecosystems. EPA-
600/3-76-001, U. S. Environmental Protection Agency, Athens, Georgia. 63
pp.
13. Lassiter, R. R. 1975. Modeling Dyanmics of Biological and Chemical
Components of Aquatic Ecosystems. EPA-600/3-75-012, U. S. Environmental
Protection Agency, Corvallis, Oregon. 52 pp.
14. Pattee, H. H. 1973. Hierarchy Theory: The Challenge of Complex
Systems. George Braziller, New York.
15. Patten, B. C. 1973. Need for an Ecosystem Perspective in Eutrophication
Modeling. In: Modeling the Eutrophication Process, E. J. Middlebrooks,
D. H. Falkenborg, and T. E. Maloney (eds.), Ann Arbor Science, p. 227.
16. Patten, B. C., R. W. Bosserman, J. T. Finn, and W. G. Cale. 1976.
Propagation of Cause in Ecosystems. In: Systems Analysis and Simulation
in Ecology, Volume IV, B. C. Patten (ed.), Academic Press, New York. In
preparation.
17. Randers, J. and D. L. Meadows. 1971. System Simulation to Test
Environmental Policy: A Sample Study of DDT Movement in the Environment.
Systems Dynamics Group, Alfred P. Sloan School of Management,
Massachusetts Institute of Technology, Cambridge. 52 pp.
18. Reiger, H. A. and E. B. Cowell. 1972. Applications of Ecosystem Theory,
Succession, Diversity, Stability, Stress and Conservation. Biol.
Conserv. 4:83.
19. Reichle, D. E. 1975. Advances in Ecosystem Analysis. Bioscience.
25(4):257-264.
20. Tomovic, R. and M. Vakobratovic. 1972. General Sensitivity Theory.
Elsevier, New York.
196
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21. Waldichuk, M. 1973. Trends in Methodology for Evaluation of Effects of
Pollutants on Marine Organisms and Ecosystems. CRC Critical Reviews in
Environmental Control, February 1973. pp. 167-210.
22. Woodwell, G. M., P. P. Craig, and H. A. Johnson. 1971. DDT in the
Biosphere: Where Does it Go? Science. 174:1101.
23. Zeigler, B. P. 1972. The Base Model Concept. In: Theory and
Applications of Variable Structure Systems. R. R. Mohler and A. Ruberti
(eds.), Academic Press, New York. pp. 69-93.
24. Zeigler, B. P. 1974. The Aggregation Problem. Manuscript, University
of Michigan. 20 pp.
197
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QUALITY ANALYSIS AND NUMERICAL EXPERIMENT IN ANALYZING
THE EFFECT OF THE ANTHROPOGENIC POLLUTION OF THE BIOTA
V.M.Voloshchuk
Institute of Experimental Meteorology,Obninsk
I, Successful application of the mathematical modelling in
various fields of science, e.g. physics,chemistry,meteorology, etc.,
revives hope in the effeciency of this method of research when used
for tackling the analyzing of the effect of anthropogenic pollution
on the biota. The analysis of the first results obtained in this
way seems hopeful in regard of the promising aspects of the method
if it is employed for solving the environment protection tasks,
particularly, the multiparameter ones, as well as in studing the
reaction to the exterior disturbance of the systems with the extreme-
ly complicated inner dynamics. Consequently, a necessity arises to
intensify the further research devoted to •nhe mathematical formula-
tion of the environment protection problems and the progressive
improvement of the methods of the mathematical modelling of these
problems and their solution. However, it is worth mentioning here
that in parallel with some specific difficulties inherent in these
problems, the difficulties of a different nature have been revealed
in the first publications on the question. These latter are mainly
due to the overliberal approach to the solution of the tasks or with
198
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a noncritical transfer of the knowledge acquired in other fields
of science to the environment protection problem. In the first case,
an unnecessarily voluminous experimental material undergoes mathema-
tical processing which, as a rule, requires the involvement of the
powerful modern computing devices without a serious preliminary
analysis. That often leads to getting rather trivial results at the
expense of much time and labour. In the second case, the mathematical
models are developed on the basis of the differential equations in
partial derivatives(the equations of convective diffusion,Shroedin-
ger's equation, etc.) without sufficient grounds for using these
types of equations to describe the processes under study.
2. The author is of the opinion that the following two ways look
most promising for the analysis of the anthropogenic pollution
effect on the biota with the help of the mathematical modelling:
- the quality analysis of the mathematical correlation formulated
on the basis of the general quality reasoning concerning possible
interrelation between various phenomena;
- the quantitative formulation of the mathematical correlation
on the basis of the analysis of the experimental material and the
general lawa of science\ carrying out of the numerical experiments
with the help of this correlation.
The efficiency of the first way can be illustrated by Voltairre's
model generalized by A.M.Kolmogorov and describing the inner dyna-
mics in the "predator-prey" system with the stable fluctiations.
The author has in this way analyzed the reaction of the biocenosis
consisting of a single independent biological population to the
199
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exterior disturbance. One of the essential results obtained has been
represented in the established opportunity for the ecoresonance to
appear in case of the combined exterior disturbances connected for
instance with the anthropogenic pollution, and capable of causing
some dramatic changes in the evolution of the biocenoses. The
actual appearance of the ecoresonance in one or another biocenosis
under the given conditions can be checked only through the numerical
experiments.
The advantages of the second course can be substantiated by the
Soviet and foreign publications of various tasks1 solutions in the
field of the environment protection.
200
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BASIC MATHEMATICAL MODELS OF TOXICANT TRANSPORT THROUGH
THE SOIL PROFILE
Dr. V.V. Rachinskii
Timiryazev' Academy of Agricultural Sciences, Moscow
I. Basic models
The general theory of sorption dynamics and chromatography [l,2j
should be used for the theoretical description of toxicant transport
through the soil profile. Specific feature of HBx^antv1 transport1
through the soil profile as compared with the ordinary sorption dy-
namics in a chromatographic column is the fact that apart from fil-
tering transport and dynamic sorption, toxicant transport is accom-
panied by the processes of chemical and microbiological decomposition
and transformation of pesticides. Moreover, in the soils with plants
present a portion of a toxicant is absorbed and removed by plants.
All these features may naturally complicate the quantitative descrip-
tion of dynamics of pesticide distribution through the soil profile.
It is necessary to choose an inductive method to solve this problem
(that is from the simple to the complex), first developing the simplest
models and then gradually making them more complex. Let us work out
basic sets of differential equations which may describe toxicant trans-
port through the soil profile.
201
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(I).The simplest model should provide for two physical processes:
filtering toxicant transport in the flow of soil solution (under rain-
fall and irrigation) and its dynamic sorption (toxicant sorption under
the conditions of mobile liquid phase filtration). These processes may
be described by a set of equations of material balance
and of sorption kinetics
(2)
With a very slow filtration, it is possible to substitute the
sorption isotherm equation
for the sorption kinetics equation assuming an approximately equilib
rium sorption process.
Solutions of the sets of equations (1-2) or (1-3) are given in
many publications on the theory of sorption dynamics and chromato-
graphy (for example, [l,2j).
(2). In the absence of sorption, pesticide transport may be des-
cribed with the filtering transport equation considering a longitu-
dinal quasi-diffusion:
. When sorption is absent, but there exist a process of pes-
ticide transformation (in particular, decomposition), it is necessary
202
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to take into account the material loss by transformation:
where /^/ ^-B ^e function of pesticide transformation kinetics.
(4). Finally, in the presence of sorption and pesticide transfor-
mation, a set of equations in general form will be:
= f fa A/) (7)
Correspondingly chosen initial and boundary conditions should be
imposed on these sets of equations. These conditions predetermine va-
rious regimes of pesticide transport through the soil profile. By ana-
logy with chromatography, it is possible to define three major regimes:
frontal, elutive and displacive flf2j. Frontal regime occurs under
continuous application of pesticide solution through the soil surface
( for example, under irrigation). Elutive regime is at first an ap-
plication of a portion of pesticide solution into the soil and then
the soil washing with water. Displacive regime is an application of
a portion of pesticide solution into the soil and then the soil wash-
ing with a solution containing a substance which desorbs pesticide.
To study the processes of pesticide transport through the soil
profile it is necessary to combine two methodological approaches:
mathematical and physical experimentations.
Mathematical experimentation means compiling the specific sets
of transport dynamics equations, solving them under given conditions
203
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and working out functions of pesticide distribution through the soil
profile.
Physical experimentation provides for carrying out physical ex-
periments to study dynamics of pesticide distribution through the
soil profile under given specific experimental conditions. Physical
experiments will yield certain parameters which may be used for ma-
thematical experimentation - simulation.
2. Asymptotic solution of the sorption dynamics problem usinp;
the kinetic parameter of time lag
An approximated sorption kinetics equation derived by the method
of lagging coordinates using the parameter of time lag ( £ ^.<* •£ )
makes it possible to take into account a simultaneous influence of
various factors on sorption kinetics disregarding specific mechanisms
of the process. Here the lag constant *t- is considered to be deter-
mined experimentally TjJ.
A set of eorption dynamics and kinetics equations with the initial
and boundary conditions takes the form:
* J/
(8)
(10)
204
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In a case of convex isotherm the stationary front of dynamic
sorption is known to be formed in the column. Changing to the mobile
coordinate system 2" ~ X - UL , where If" is the velocity of the
stationary front movement, it is possible to integrate the set of
equations (8)-(9) and to transform it as follows:
ctn n- h f(n)
= r*°'~ (12)
Let us introduce the relative concentrations a —/?//?o and
and consider the Langmuir isotherm of sorption:
(13)
«fc ' A-» J
where Q - & =1.
After algebraic transformations we may obtain the following ex-
pression:
•5 ff iin ,-*-/ rs • o i »\ r/n
C.
f-a) V
Now integrate the expression (14) on the assumption that the iso-
therm is slightly curved, that is cf^/C/^f^ const, (in a case of the
Langmuir isotherm it is equivalent to the condition D^^ I) and
determine the integration constant C [l»2j. Tnen we may obtain the
following expression:
where _
L ~~ *~ ?J-2
" (16)
205
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Since from the solution of the set of equations (8)-(9) it fol-
lows that !/=" V , , the expression (15) may be finally written
as follows:
The expression (17) agrees with the result obtained in work
for the Langmuir isotherm and the diffusion kinetics equation
C J """ * ) where B is the sorption kinetics constant.
In comparing it is seen that j ~ ^ • The introduced parameter
additive ly allows for kinetic and longitudinal effects.
3. Equilibrium sorption dynamics at a variable velocity of the
mobile phase
In some cases one has to study the process of toxicant sorption
dynamics at a variable velocity of the mobile phase: Uzz-fyft:). Let
us consider the following initial set of equations for equilibrium
sorption dynamics at a variable flow velocity:
(19)
Using the change dT/ot = U&)/1 L + $ (/7 ) J) we may ob-
tain the following expression from (18) and (19) :
(20)
Now give the following initial conditions: £ = 0(^=0)^ fl =/7o
206
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where f)o is some characteristic concentration and W-K/ is the con-
tinuous function of initial material distribution.
The method of characteristics (initial value problem) for the ex-
pression (20) leads to the following formula:
o (22>
Since iff?) is the arbitrary function, it is possible to choose
the unit function Cfej ~ £6* ~~ ^) as a solution. Then the solu-
tion to the equation (20) will also be the following function:
n fl-i — •/ -. ^ /^ } W- ^ /V )
n //in — 1 LC*' ^ T I*/ (?"*>}
I *^ V ^~ ^ X
The solutions (21) and (23) satisfy the initial condition (20)
and boundary conditions:
n = n0 (24)
n=0
(25)
The condition (24) is the frontal sorption dynamics and the con-
dition (25) is the elutive sorption dynamics. The solutions (21) and
(2J) may also be obtained by the method of operational calculus. In
this case the Laplace transformation must be performed first with
respect to X and then with respect to u . A limitation of this method
is that the validity of the solutions is only proved for the linear
sorption isotherm.
From the solutions (21) and (23) we may obtain a generalized ex-
pression for Wicke law £5]:
207
-------
(26)
The solutions obtained are general, and the solutions of equilib-
rium sorption dynamics at It - const, are the special case of the ob-
tained ones.
Designations
H is the linear sorbate concentration in solution in the soil
pores;
N is the linear sorbate concentration in sorbed state;
H0 is the initial and equilibrium concentrations of sorbate in
solution;
M, is the equilibrium concentration of sorbate in sorbent which
corresponds to the concentration H.Q ;
V is the distance from the soil surface level;
± is the time of the process;
££)* is the quasi-diffusion coefficient of longitudinal sorbate trans-
port additively accounting all the factors of non-filtering longitu-
dinal transport: molecular diffusion, hydrodynamic statistical non-
uniformity of the mobile phase flow;
*C is the characteristic time lag formally accounting sorption ki-
netics.
208
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References
I. B.B. PaiMHCKMft (v.v. Rachinskii ). BseaeHMe B odmyio TeopHM
UUKVL coptfuMH H xpOMaTorpa$MH. M., "HayKa", 1964.
2. V.V. Rachinskii, The general theoiy of sorption dynamics and
chromatography. Consultants bureau, New York, 1965.
3. C.E. Epecaep, fl.C. y$JiHHfl (s.E. Bresier, Ya.s. Uphland )•
TexHW^ecKoa $H3KKM1 T. 23, N?3, 1953.
4. B.B. Paq^HCKHfi (v.v. Rachinskii ). K TeopMH craaHOHapHoro $pOHra
copduHM. B c(5. "HccjieflOBaHHfl B ocJjracTH HOHOodweHHOti
M ocaao^HOtt xpowaTorpa^HH". M., Has. AH CCCP,
1959.
5. E.W. Wicke. Koll. Zst., 1939. B. 86. H. 2.
209
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MATHEMATICAL MODELING AND CONTROL AS A RADICAL WAY OF THE
ENVIRONMENTAL PROTECTION PROM PESTICIDE CONTAMINATION
E. I. Spynu
Research Institute of Hygiene and Toxicology of Pesticides,
Polymers, and Plastics, U.S.S.R. Ministry of Public Health, Kiev
The biospheric protection from pesticide contamination aimed at
safegarding the "healthy biosphere" is based on the complex of stages
including prediction of the substance behavior and control over this
process, check of the control accuracy, and introduction of the pre-
diction and control corrections, L. I. Medved* (I971) points out
that when considering the pesticides purposely dispersed in the en-
vironment, emphasis should be placed on the prediction stage. At the
stage of preventive supervision it is necessary to work out regula-
tions and standards as well as to test the conditions of pesticide
application which provide the environmental protection*
Thus, preventive measures against contamination of the human in-
habitation environment should be considered as a problem of control
over the pesticide-environment system including all stages of the
pesticide routes
I. Dissipation in the environment.
2. Distribution on the objects (plants, soil, water).
210
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J. Behavior in each medium.
4. Migration between the media.
5. Total disappearance from the biosphere.
This principal of the activity arrangement will provide opportu-
nities to determine and regulate the conditions of their application
acceptable from the viewpoint of both hygiene and plant protection
before the dispertion of pesticides in fields, forests, and gardens*
It is known that the behavior of chemicals in the environment
£s a very complicated process. This is a complex of various changes
described by the laws of hydro* and aerodynamics as well as chemi—
oal kinetics (the number of simultaneously occuring chemical reac-
tions is not amenable to the precise quantitative estimation), in-
teractions with living organisms, effects of the evolution factors,
and others.
Thus, we consider a complicated, dynamic, and multidimensional
system which is made up of a great number of subsystems, elements,
and bonds (as any large system). The problem is to control this sys-
tem at the quantitative level, that is the stages of modeling-pre-
diction also are required on this basis of control over the process.
As the initial stage, it is advisable to represent schematically
the pesticide-environment system being described to a first appro-
ximation. Generalization of the published data and our observations
enabled us to propose a hypothetical model of this system (Figure I).
Four subsystems have been conditionally chosen (air, soil, water,
and plants) and major factors have been named which define concent-
ration as a function of time within each block and between them.
211
-------
Fig. 1
to
»-«
to
X2, ,X
23
|c=f(t) in basins]
jc_= fU) in air]
[~C = £(t) in soil
,
C = f(t) in plantsH
-------
To Figure It
Xj is the pesticide molecular weight;
X2 is the temperature of pesticide Belting (boiling);
X3 is the fat solubility;
X^ is the water solubility;
X5 is the pesticide persistence at pH of 5-8;
Xg is the pesticide volatility;
X- is the pesticide persistence at pH of 5;
X8 is the pesticide persistence at pH of 8;
Xg is the plant pH*
10*10 is the water content of plants;
is the total acidity;
25
XT2 is the nitrous substance amount;
is the fat amount in plants;
is the cellulose amount;
is the ashes content;
is the pectinic substance amount;
is the content of proteins;
is the total amount of sugar;
is the frequency of treatments;
X2O iB the rate of P*8ticlde application on treatment;
X2I is the average air temperature;
is the total precipitation;
is the relative air humidity;
28
30
33
37
58
39
40
and
is the velocity of air movement;
is the humus content in soil;
is the soil pH;
is the absorbing capacity;
is the soil moisture capacity;
is the soil density;
is the mechanical composition of soil;
is the total absorbed bases;
is the amount of phosphorus compounds;
is the nitrous substance content;
is the amount of fertilizers applied;
is the microorganisms;
is the species of nurse crop;
is the yielding capacity of nurse crop;
is the depth of root system bedding;
is the trade mark of the chemical which entered the soil;
is the way of chemical application;
is the average soil temperature;
is the soil moisture;
is the water pB;
is the amount of oxygen dissolved in water;
is the water temperature;
others.
-------
Questions arise concerning the process of pesticide interaction
within each subsystem as well as changes of the effect with chang-
ing these or those input and internal variables and interactions
between the adjacent media* The number of measurements necessary to
describe these processes is incredibly great (the level and dura-
tion of pesticide content, meteorological parameters, biochemical
and chemical reactions, etc.). It is impossible to take account of
all these factors experimentally as a great number of variables and
variants of interactions changes. Necessity is evident to use the
methods of cybernetic modeling for description of the problems of
this kind.
Let us consider this approach using as an example the pesticide-
plant subsystem*
We have systematized and classified the data of world publica-
tions and our experimental investigations in dynamics of degrada-
tion of pesticides belonging to different chemical classes in va-
rious species of plants under the varying conditions of application*
When generalizing this information, an attempt has been made to re-
veal the sequence of the pesticide-plant interaction mechanisms tak-
ing place and factors which determine them. There is little informa-
tion on this problem.
It has been found that a number of biotic and abiotic factors
are of substantional significance in the process of pesticide degra-
dation and that the physical and chemical properties of compounds
play a leading role in the outcome of the process of interaction
with plant organism. Of great importance in the mechanism of pesti-
214
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cid« transformation are the factors of plants. So when applied on
•the plant, the stock of substance undergoes a number of quantitative
and qualitative changes under the influence of the experimental con-
ditions and properties of plant surface. Penetrating deep into plant
tissue, pesticide may undergo various transformations in hydrophi-
lous fractions and accumulate in lipophilous tissues. Formation of
complex compounds with carbohydrates, amino acids, and other plant
components may be one of the forms of substance transformation. There
are various types of pesticide biotransformationt oxidation, hydro-
xylation, epoxidation, N-dealkylation, dehalo- and dehydrogenation,
conjugation with sugars, etc. It is evident that plant enzymes have
a dominant role in the processes of pesticide degradation and trans-
formation.
However, the information available covers only individual small
links in the chain (or chains) of numerous reactions of the pesti-
cide-plant interaction.
It should be emphasized that since the process of this inter-
action occurs under the conditions of continuously varying numerous
factors of the environment, these latter have a pronounced effect
on the outcome of the process causing new numerous bonds and reac-
tions.
The foregoing proves that it is very difficult to choose the
type of mathematical description of the process being considered.
When describing complex systems, complete knowledge of the pro-
cess is commonly absent. Then one may neglect the "unessential fac-
tors" * random effects, influence of the conditions external to the
215
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given system, aad other uncertainties in the information and if it
is still possible to gain a general idea of the behavior of chemi-
cal and a role of the essential factors, the classic apparatus of
differential equations can be used. However, such information is
not available for the subsystem being considered in terms of the
problem set*
It is evident that advisable is the use of the models on the
"black box" principle. Probability statistical approach makes it
possible to be satisfied with the information on the actual course
of the process digressing from the essence of physical and chemical
and chemical and biological reactions.
In the last few years the theory of image identification has
been used to predict multidimensional process with the information
of this kind available. To synthesize the model we have used one
of the methods of heuristic self-organization, namely the method
of group analysis of arguments (Ivakhnenko, A.G., I971).
The information accumulated contains the data on 90 processes
of pesticide degradation in fruit and vegetable (except roots and
tuber-plants). The data have been analyzed which characterize ki-
netics of 15 pesticides belonging to different chemical classes
under various conditions of their application. 22 indications
both direct and indirect, were taken into account and quantitative-
ly evaluated (we used direct measurements and the method of ex-
pert estimates). Analysis of these data showed that four groups
of factors affect the rate of pesticide degradation (Figure 2)t
I. Physical and chemical properties of pesticides (molecular
216
-------
weight, melting temperature, fat solubility, water solubi-
lity, persistence at different pH values, volatility).
2. Treatment conditions (number of treatments, rates of pes-
ticide application)*
3. Climatic parameters of the environment (average air tempe-
rature over the period from the beginning of treatments to
the end of investigations, total precipitatiom over the
same period).
4. Properties of plants.
Fig. 2
Physical and
Chemical Properties
of Pesticides
Conditions
of Treatment
(Xe . . . Xm)
Chemical Properties
of Plants
' ' ' V
Climatic
Parameters
Determination of these latter turned out to be the most compli-
cated. Taking into consideration that the problem is not clearly
understood and the information available is scant, we assumed hy-
pothetically that all components of the chemical composition of
plants directly or indirectly participate in the process of pes-
217
-------
ticide interaction with plants. In accordance with this, the fol-
lowing factors were considered: pH of the culture, water content
of plant, total acidity, nitrous substances, fats, cellulose, pec-
tinic substances, ashes, proteins in culture, total amount of su-
gar in plant.
Exponent has been used as an approximating function of dynamics
of the process being studied. Classification has been performed
with the time constant value.
The formula of identification of the pesticide conservation
duration in crop products is of the following form:
Pa(X/Ri) =
where P (X/R.,) is the probability of classification of the process
ft ~
with a certain class;
) is the probability of indication combination oc-
curence in the H^ class.
In terms of practice, the method of calculations provides op-
portunities to predict the level of residues and life duration of
a given pesticide in various cultures at different climatic para-
meters and under different conditions of its application.
Verification has been made at the experimental plots in eight
climatic and geographical zones of the Soviet Union (Estonia, Lat-
218
-------
via, Lithuania, Byelorussia, Ukraine, Moldavia, Georgia, Armenia)
to test the hypothesis validity and possibility to use the formula,
The results of comparison between the calculated data and actual
information obtained at the experimental plots in the above-men-
tioned zones of the country showed that the average accuracy of
prediction was ?0#.
Several examples are given in Tables 1,2 and Figures 3,4.
Table I. Comparison of the actual and calculated data on
the duration of conservation of several orgauo-
phosphorus pesticides in apples and tangerines
: Pozalon : Phthalophos : Anthio : Carbophos : Phosphamide
Pesticide : (zoloa) . (imidane) : (formothion):(malathion):
: Duration of conservation
Culture
:Act.:Calc.x):Act.iCalc.: Act.:Calc.J Act.:Calc.s Act.:Calc.
•--,,.-._!_-,-,„ „* ,-,-Jr !._.-*... : * : .'.__-—_.
Apples 30 35 20 26 18 25 18 25 20 26
Tangerines 12 21 12 21 18 25 17 21 12 20
x'Upoer limit of the calculated value.
These data were obtained by L. G. Adeishvili, 1975.
The stages mentioned - model synthesis and prediction are ne-
cessary to achieve the primary practical purpose - control over
the pesticide-plant system with regard to the requirements of hy«
219
-------
Table 2. Comparison of the actual data on the. duration of
conservation of several organophosphorus pesticides
in cherries and sweet cherries
Pesticide «
Cidial : Carbophos : Metathion : Phosphamide : Fozalon
, (papthion) :(malathion) :(byer 4I8JI) j
: (aolon)
Duration of conservation
Culture
!Act. : Calc.x's Act. : Gale.:Act.:Calc.: Act. : Calc.:Act.:Calc.
: : t :::::::
Cherries 20
Sweet
<£h-erries___
20
25
25
16 16 15 16 20 25 48 60
15 16 II 16 21 24 50 62
Upper limit of the calculated value
These data were obtained bj E. Z. Ordzhonikidze, 1975
Fig. 3
C(mg/kg)
1.67 -i
',5
1,2 -
-A actual
A a calculated]
o o actual
o o calculated
• actual
• calculated
tangerines
apples
grapes
t(days)
220
-------
A
actual "I
calculated]
actual
-Q calculated
actual 1
calculated]
tangerines
apples
grapes
Fig. 4
12
17
20 t(days)
glen* and plant protection. It is essential that when predicting
tiae, Bite, and numbers of pests, calculation of the level of re-
sidues and pesticide degradation duration under the given specific
conditions should be performed. This combined prediction will pro-
vide opportunities to choose the control decision approaching the
optimal one.
On the basis of these data it is possible to perform sorting
out of variants (pesticide assortment, species of culture, etc.).
The general diagram of control over the process is shown in Figure 5
where computer symbolyzes the predicting system which can be the
prediction formula at the lowest level of organization and State
predicting system - at the higher level.
Description of the individual environmental components as a
large and complex system is the most important element of the pes-
221
-------
ticide behavior prediction and control from the moment of pesticide
dispersion when treating plants, distribution in various media,
fate in each of them, and migration between them to the complete
disappearance from the biosphere.
Fig. 5
Physical and Chemical
Properties
Conditions of
Application
features
of Medium
Computer
Formula of
Identification
Change of
ReguLations
Befepeaces
Authorization
of Application
Yes
Comparison
with Standards
No
Ivahkaenko, I.G., Spynu, E.I., et al. "Gigiena i Sanitarija",
No. 10, p. *3 (1972).
Ivahknenko, A.G. "Systems of Heuristic Self-Organization in Tech-
nical Cybernetics*1, Kiev, Technika (1971).
Medved1, L.I. Im "Pesticide Application Hygiene, Their Toxicolo-
gy, and Intoxication1*, Kiev, Izd-vo VNIIGIHTOX, J, p. 5 (1971).
Spynu, B.I. and Ivanova, L.N. "Voprosy Pitanija**, No. I, p. 76
(1976).
222
-------
MODELING OP PESTICIDE DEGRADATION IN PLANTS AND EVALUATION
OP THEIR APPLICATION SYSTEMS
L. N. Ivanova
Research Institute of Hygiene and Toxicology of Pesticides,
Polymers, and Plastics, U.S.S.R. Ministry of Public Health, Kiev
Increasing efficiency of the preventive system of pesticide
contamination of crop production is possible under the properly
chosen conditions of pesticide application (rates of pesticide
application, frequency of treatments, terms of carrying out treat-
ments before harvesting) with regard to the persistence of these
substances and properties of the medium. A possibility to choose
an acceptable variant of the conditions mentioned should be cre-
ated before carrying out treatments.
One of the ways to solve this problem is the use of the me-
thods of modeling, prediction, and monitoring. The second step is
presently made on the way of mathematical modeling of pesticide
content dynamics in plants consisting in the development of an
improved mathematical model (L. N. Ivanova, 1976)* The first step
on this way was the previously developed probability model co-
vered rather comprehensively in several publications (A. G. Ivakh-
nenko, et al., 1972% E. I. Spynu, L. N. Ivanova, 1975% etc.).
223
-------
The previously developed probability model provides a simpli-
fied calculation of pesticide level and duration of conservation
in fruit and vegetables which is acceptable for practical use;
however, this model has somewhat limited possibilities of predic-
ting and monitoring the process of contamination. To develop this
model the problem of statistical classification of the processes
being studied by the level of pesticide content and duration of
their conservation has been solved, that is the parameters men-
tioned have been divided into several classes. As a result, the
prediction amounts to identifying the class into which the pre-
dicted quantity falls.
Natural was a desire to develop a more accurate model of pes-
ticide disappearance from plants for the purpose of prediction.
Some investigators believe that the most accurate models which
more completely reveal the regularities of the phenomena being
studied can be developed by means of the apparatus of differential
equations. It has been this approach that has been applied along
with the algorithm of differential identification.
It should be noted that in modeling pesticide degradation a
great body of information on the cause and effect relationships
was brought a priori. There is no doubt that in so complicated
phenomenon as the process being studied these relationships were
not clearly traced, the more so as the mechanism of its proceeding
was not revealed equally and completely for the majority of pes-
ticides. However, the information on possible mechanisms is con-
taiaed in the experimental data and can be used for solving the
224
-------
problem of prediction* Mathematical methods have been developed
to handle incomplete and inaccurate information characterized by
both direct and indirect indications. These methods provide pre-
diction accuracy acceptable for practical use* We used one of
them, namely the method of group analysis of arguments synthesized
by A* 6. Ivakhneako (I971) in modeling the process of pesticide
disappearance in plants* This method was used to solve other prac-
tical problems, such as calculation of hydrobiological parameters
(J. Duffy and H, Franklin, 1973) aad others.
The process of pesticide content reduction in the plants con-
taminated by them can be described by the following equation:
dC(X,t)
dt
- = C(Xtt)
n - I
(I)
where Kj(X), K2(X), ..., Km(X) <: 0 are the negative constants of
the rate of the process;
X is the vector characterizing the physical a&d chemical
properties of pesticides, features of plants, conditions of
treatments, and climatic parameters*
An acceptable accuracy is obtained with two members on the
right side of the equation available* Direct integrating is pos-
sible providing
* dKT(X) dK2(X)
__i « —£ - o,
dt dt
and each individual process is described by an equation of the
form:
225
-------
CA(X) • e"KI(x)t
C(X,t) = 2 ...—
I -
where C(X,t) is the current pesticide concentration;
C (X) is the initial pesticide content in the vegetative
object;
Kj(X) and Kp(X) are the constants of the rate of the pesti-
cide degradation process.
It is possible to restrict oneself to one member on the right
side of equation (I) and approximate the contamination reduction
process to exponent. The description obtained provides possibiliti»s
to determine the rate constants Kj(X) and I^CX), and the current
concentration C(X,t) from the values of vector X known beforehand
at the moment of time t which is of interest to us.
The process being studied is amenable to control, and the pro-
positions worked out to fit the control systems are valid for it.
According to R. Lee (1966), two problems are to be solved to ana-
lyze these control systems:
I. Direct problem - the description of dynamics of the object
or process being studied.
2. Inverse problem - the indification (finding) of parameters
from the experimental data.
So we have made an attempt to solve both problems for the pro-
cess of pesticide degradation, that is not only develop the des-
cription of an individual process but also identify its constants
226
-------
and, using them, predict the output value C(X,t). This provides
opportunities to control a given value by meaas of the properly
chosen conditions of carrying out treatments.
Using the prediction formulas, it is possible to calculate the
moment of time at which pesticide treatments of farm crops are to
be carried out before harvesting, that is the so called waiting
time (tw), with the values limiting food stuff contamination avail
able (FRA - permissible residual amounts). tw can be calculated
with formula (3) assuming the first order kinetics to be dominant
in the process of pesticide disappearence:
In FRA - In C.(X)
From the hygienic viewpoint, the relation between the predicted
level of pesticide content in the object which is of interest to ust
that is C(X,t), and the value of FRA can be used as a certain
dimensionless index of safe application of a given chemical.
Residues of several pesticides may be found in the yield by the
moment t_ due to the wide-scale use of the systems of farm crop
chemical protection with certain assortment of chemicals and se-
quence of their application. To evaluate food stuff contamina-
tion in this case it is necessary to introduce an index defining
safety of these systems of plant protection. As one of these in-
dices, the dimensionless quantity can be used which is calculated
with the following formula:
221
-------
QC V
PRAi
where Q(tw) is the safety index of the system which is always
less or equal to unity;
K^ is the reserve coefficient which allows for possible
newly revealed adverse effect of the pesticides being stu-
died;
C(X,tw) is the concentration of the i pesticide at the
momemt of harvesting.
Thus, the obtained mathematical models of pesticide degra-
dation in plants provide opportunities to calculate an approxi-
mate level of pesticide contamination of fruit and vegetables
and not only determine but also choose the acceptable regula-
tions of pesticide application (waiting time). The formulas have
been developed which make it possible to evaluate safety of the
application of one pesticide as well as of a system of quite a
number of chemicals.
228
-------
Refer*ac«s
Duffy, J. and Fraaklin, H. "A Cases Study of Environmental System
Modeling with the Group Method of Data Handling", Ohio State
University, Columbus, Ohio. June, pp. IOI-III (1973).
Ivahknenko, A.G. "Systems of Heuristic Self-Organizatioa ia Tech-
nical Cybernetics", Kiev, Technika (I97D.
Ivahknenko, A.G., Spynu, E.I., Patratii, I.Z. and Ivanova, L.N.
"Mathematical Predicting of Pesticide Degradation Duration ia
Plants According to Probability Algorithms of the Method of
Group Analysis of Arguments", "Gigieaa i Sanitarija", No. 10,
p. 43 (1972).
Ivanova, L.N. "Improved Model of Pesticide Behavior in Plants and
Evaluation of the Systems of Chemical Protection Application".
In: "Application of Mathematical Methods to Evaluate aad Pre-
dict Real Pesticide Hazard", Kiev, Izd-vo VNIIGINTOX,p. 25
(1976).
Lee, H. "Optimal Estimations, Determiaatioa of Characteristics,
and Control", Moscow (1966).
Spynu, E.I, and Ivaaova, L.N. "Methodical Instructions on Predict-
ing Pesticide Residues in Crop Production and Terms of Carry-
ing Out the Last Treatments", Moscow, Publishing House of the
U.S.S.R. Ministry of Agriculture (1975).
229
-------
THE MODEL OF THE PESTICIDE CIRCULATION
IN FERGANA VALLEY
(Koropalov V.M., Nazarov I.M,)
In this paper by an example of Fergana Valley a mathematical
model is considered which describes pesticides circulation in the
intermountain valley with a limit-^ed release outside. We were in-
terested in what aspects of the pesticide cycle are principal and
what is the possibility to assess the permissible loading on the
ecosystem, »Ve tried to obtain adequate description of the pesticide
circulation with the help of minimum number of parameters, which for
rather reliable estimates could be obtained. In Fergana Valley DDT
was used until 19'/0 when it was prohibited. / /,£,3/. Residual
amount of DDT circulating in the ecosystem, allowed us to get ex-
perimentally a number of transfer parameters, a part of parameters be-
ing taken irom literature. / f , g ,ff /. .»e consider pesticides
transfer between One atmosphere, soil, waoer .nd vegetation. In
Fergana Valley a rather high agricultural cultivation of the ter-
ritory caused a wide development of erosion / ^/. This, in its
turn, favours soil particles polluted with pesticides to enter the
atmosphere as a result of weathering. At the same time a high air
temperature in this region favours pesticides evaporation from the
soil surface and vegetation and then volatilizing with water vapours
230
-------
Life-time of gaseous and aerosol fractions of pesticides in the
atmosphere differ significantly, so it seemed reasonable to consider
aerosol and gaseous fractions of the pesticides in the atmosphere
separately. Further, since pesticides are applied not over the whole
area of the valley, all the soil in the model is divided into two
parts: soil I - fields treated with pesticides; soil II -
the residual area of the valley where pesticides were not applied.
Due to this very reason we consider vegetation only on soil where
pesticides are not applied directly. The differential equation set
describing the circulation of pesticides between the ecosystem media,
can be written as following
c*p-+ +
ctt *. ,
.t f_
J- (*«£ + »ixCz \ _ C,
^( r» 7?s ' Ta
Tf
C,
231
-------
where Cy, C2 - pesticide, concentration in the atmosphere, in ... aero
sol and vapour phases, respectively .
C-jUn - pesticide, concentration in soil I and II,
Cc - pesticide concentration in water.
C, - Pesticide•; concentration in vegetation,
" atmosphere volume of ...j Fergana Valley.
— mass of the surface layer of soil I and II.
— water mass.
- vegetation mass.
P - velocity of incoming pesticides into the valley.
ft - a fraction of pesticides falling-out directly on the fields
during treatment.
-fi)- » fraction of pesticides released into the atmosphere in the
form of aerosols during field treatment.
-/) - a fraction of pesticides released into the atmosphere in the
form of a vapour phase during field treatment.
7\'/ - retention time of pesticides in i-th medium determined by
pesticides transfer from i-th medium into J (^J )
Tii ~ retention time of pesticides in 6-th medium,determined "by
direct decomposition in <--th medium.
Ti - total retention time of pesticides in c-th medium.
TV "
Now let us consider and assess pesticide fluxes between various media
of our ecosystem. Further all specific estimations of the pesticides
fluxes will be performed for DDT v/hich found the widest application
232
-------
Its displacement between different media is studied most completely
compared with other pesticides / 10, II/. When developing the model,the
amount of DDT released into the atmosphere at th» moncnt of application
and due to secondary application is supposed to "be homogeneously mixed
throughout the whole air volume of Fergana Valley and then fall-out
uniformly over the whole area. The sedimentation velocity of DDT,
connected with a coarse-dispersed aerosol according to our data is
o
within(0.4— I.2)»IO~ m/sec. For the DDT vapour sedimentation from the
atmosphere two estimates are known, namely ,4* 10 cm/sec and 5*IO~'Tn/sec,
In the first case the rate of DDT vapour deposition on glass was
measured, in the second one - that on water surface /9/ •
Usually, vapour and aerosol pesticides phase present in the atmos-
phere simultaneously. It is found, that often only about half of DDT
in the atmosphere is in the vapour phase and in the atmosphere with
increased aerosol content this part is still less /£ /. To take
into account the effect of meteorological parameters on the atmospheric
transfer of DDT there was considered a two-layer atmospheric model
of Fergana Valley. Vertical distribution of DDT in the atmosphere both
for aerosols and vapours was described with the help of tae equation*
C$>e*f>[%f
I—
**- *-*> *****
where IK.*^* - coefficients of turbulent exchange in the lower and
upper layer.
233
-------
/,£ - sedimentation velocity of DDT vapour and aerosols,
respectively ,
n
" - the altitude of the lower and upper layer of the
£ atmosphere, respectively .
- surface air concentration of DDT vapour and aerosols
respectively.
vVith allowance for particularities of the air-mass exchange in u'ergana
Valley / £ / DDT transfer beyond its limits can take place through-
out the year only across the upper atmosphere boundary and periodi-
cally in case of Ursatjevsky wind. Though methods of pesticide income
can be various, in principle they reach soil surface. Soil is like
a reservoir for pcsticio.es where they are either transfered into
other media or decomposed. Quantitative assessments of pesticide
flows due to uptake by plant root system, washout with surface
run-offs, carrying away with dust, and volatilization were taken from
papers / & , 9 , /£/. The systematic application of pesticides on
areas the most part of which is a watershed, leads to a fact, that
run-off of melted snow, rain and irrigating waters from agriculture
fields becomes?-a source of water-bodies pollution. Waste waters from
the irrigated territory of -b'ergana Valley are removed into continous
hollows and rivers. Di>T decomposition in water was studied in paper
/ & /. It was found that time of DDT decomposition in water changed
vitiiin 112-139 ciays depending on pH. Since the river system has its
output beyond the valley, part of pesticides will be carried away due
to natural water exchange.
With a help of our model we tried to follow dynamics of DDT re-
distribution in Fergana Valley throughout a year. DDT concentration
234
-------
in different media was calculated with a period of a month. Mean
values of parameters used in the model are given in 1'able I. Some
parameter values (showing DD11 income into the system, valley airing^
Table I
Mean Values of Model Parameters
IW-1 45-10^ km^
45-103 km3
24-108 t
50-108 t
fne 8-106 t
/< O.J»
^ oo
& o
^ 0.2 km
^ 2 km
K' 1 m2/sec
K^ 10 m/sec
"^ 1-10~2 m/sec
^< 1-10 m/sec
1-10 1/moat/l
2-10~2 -ii-
KC3.3) 1.1-1U-1 -ii-
K^'O ^.'o-4 -.-
K(^(<2) 2-10"2 -ii-
KC^j^) 1.1-io~1 -ii-
K (^,^) 1.7-10"5 -ii-
Kr f
-------
DDT evaporation from cultivated fields) change considerably throughout
a year so they were taken as time functions. Thus rate of Di)T incoming
into the system was described with a function
where P^ - amount of DDT entered the valley for a month during a pe
riod of maximum application, £ - coefficient of increased DDT appli
cation. In this paper ^e give only calculations for a constant velo
city of application of DDT (i.e. fa = 0) at a rate -of
10 kg/ha. The decrease of DDT concentration in the atmosphere when
airing the valley, was as following
/ xi . /gt- u )
dC±z _ /o CQ^ 17£V ^ £ ^
where TJJ = one day, i.e. valley airing for a period from June to
December is supposed to increase from null to maximum possible. Re-
sults of some calculation versions are given in i<'ig. 1-2. The relat-
ion of vapour phase to aerosol one equal to 1:2 was assumed to remain
constant in the atmosphere. Initial concentration in all media was
supposed to be equal to zero. Redistribution of DDT between media
was calculated for the first two years since the start of DDT appli...
cation. The change of a mean atmospheric concentration of DDT associa-
ted with the aerosol for two states of the atmosphere is shown in
cthe,
Mg.1. InVTirst case a good mixing in the atmosphere (K. = 10 m /sec
for the whole atmosphere of the valley) and airing are supposed. In th
236
-------
1*
--
I
1
6 U 19
time <•«. tnantA.)
Pig.1, Mean concentration of DM (aerosols) in the atmosphere.
(1) - f^ s 1, &, = 10 m2/sec, zx = 2 km;
(2) - f,, = 1, Kn = 1 m2/sec, K2 = 10 m2/sec, zx = 0.2 km,
airing is absent.
second case there is no airing^and mixing is much weaker ^K =1m /sec,
Kp=!0m /sec, zx=20(Jm), Mean DDT concentrations in the atmosphere in the
, the,
case of good turbulent mixing is 4 times higher tttan irfSase of bad
one. It's worthnoting that mean concentrations characterize total
content in the atmosphere. If pass from mean concentrations to air
surface one we'll find that suri'ace atmospheric concentration of DDT
the,
i'fiYBecond case is higher compared with the first one. In order to
estimate the role of the atmosphere for DDT dispersion we calculated
concentration in water for two cases: inVfirst case DDT was sup-
posed to enter water due to wash-out of soill and due to the atmosphe-
237
-------
rthe,
ric fall-outs, rnYsecond case, - DDT comes to water only due to the
atmospheric fail-outs. The calculation results showed that DDT income
into water is mainly through the atmosphere. Consequently a conclusion
may be made that a principal role in the redistribution of DDT between
various media belongs to the atmosphere. The removal of DDT beyond
the valley, as it was said already, can be while airing the valley
and across the upper atmosphere boundary due to the turbulent dis-
persion. DDT flows from the valley are shown in Fig.2 for the case
when half amount of DDT at the moment of its application falls out
3 Jl
titne (a. mofit/i)
(1) rate of DDT incoming into the valley.
(2) DDT removal from the valley when airing.
(3) DDT removal across the upper boundary of the valley,
238
-------
on the fields and half of it enters the valley atmosphere. On the
basis of the calculations it follows that DDT removal outside the
valley^HO^ from the used quantity. In conclusion we should like
to note, that this model can probably be used to describe pesticide
circulation in other regions. The values of a number of parameters
should be changed but this will change the general picture of pesti-
cide circulation in the biogeocenosis.
References
I. ffl.T. AiadaeB (Sh.T. Atabaev ), IlecTMiwujt H rumena BHemnefl
B ycjiOBMHx acapKoro KJiuwaTa. HssaTCJiLCTBO "MejHUHHa", 73CCP, Tan-
K6HT, 1972.
2. r.A. BeJIOHOKKO, K).A. KyqaK (G.A. Belonozhko, Yu.A. Kuchak), TH-
xapaKiepMCTMKa coaepxaHHH necTwmwoB B aTMOc$epHOM B03-
. B KHwre: FHrueHa npHueHeHMH, TOKCMKOjiorHH IUCCTMUHAOB H KJIM-
tt, 1970.
3. K.A. IIoHa$HAMH (K.A. Ponaphidin), CoxpaHeHHe necTHitMaoB na xjion-
H B no^Be XJIOHKOBUX nojieft. Tpyau Bceco»3Horo HayMHO-Hccjie-
HHCTMiyTa sautHTti pacieHHti, sun. 35, cip. 81, 1972.
4. K.C. KaJILHHOB (K.G. Kalyanov ), flHH3MHKa npOUeCCOB BeipOBOli 3p03MH
no^B. Ha^aTejiBCTBO "HayKa", MocKBa, 1976.
5. C.r. tJaHiimeBa (B.G. Chanysheva ), UeCTHUe B6TPH CpeflHeK A3MH.
, 1966.
239
-------
6. E.H. roHwapyie, B.M. UanpHH, K.C. CTe$aHCKHfi, B.PI.
(E.I. Goncharuck, V.I. Tsipryan, K.S. Stephanskii, V.I. Perelygin),
GTOflKOCTH necMiWEiOB B BOfle, noqse H pacTCHHHx.
M caHMiapHfl, N2 10, 1975.
7. J. Randers, DDT movement in the global environment, p. 49. Toward
global equilibrium. Ed. by D.L. Meadows and D. Meadows, Cambridge,
Massachusetts, I975»
8. J. Cramer, Model of circulation of DDT on earth. Atmospheric Knvi-
ronment, vol. 7, p. 241, 1973.
9- G.A. Whatley, Pesticides in the atmosphere. In: Environmental pol-
lution by pesticides, ed. by C.A. Edwards, 1973.
10. C.A. Edwards, Knvironmental toxicilogy of pesticides. London, 1972,
II. W.F. Spencer, Movement of DDT and its derivatives into the atmos-
phere. Residue reviews, vol. 59, p. 91, 1975.
12. W.F. Spencer, W.F. Farmer and U.K. Chath, Pesticide lolatilization.
Residue reviews, vol. 49, p. I, 1973.
240
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
REPORT NO.
EPA-600/9-78-003
2.
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
Symposium on Environmental Transport and
Transformation of Pesticides
5. REPORT DATE
February 1978 issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
S. G. Malakhov, Co-Chairman, U.S.S.R. Side
David W. Duttweiler, Co-chairman/ U.S. Side
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Environmental Research Laboratory—Athens, GA
Office of Research and Development
U.S. Environmental Protection Agency
Athens, Georgia 30605
10. PROGRAM ELEMENT NO.
1BA609
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
Same as above
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
EPA/600/01
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Under the USA-USSR Agreement on Cooperation in the Field of Envi-
ronmental Protection, a joint project committee on environmental trans-
port of agricultural chemicals (pesticides and fertilizers) sponsored a
symposium on 20-27 October 1976 in Tbilisi, USSR. Papers were presented
by American and Soviet scientists on the movement and transformations of
pesticides in the atmosphere, in soils, in water, in plants, and in ani-
mals, and on the use of mathematical modeling to describe the transport
and transformation of pesticides in the environment. Twenty-six papers
encompassed reviews of the state of the art in each country and results
of research on particular aspects of the topics.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
COSATI Field/Group
Pesticides
Agricultural chemistry
Transformations
Pollution
12A
57P
68A
68D
68E
13. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (ThisReport)
UNCLASSIFIED
21. NO. OF PAGES
249
20. SECURITY CLASS (This page)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (»-73)
241
• U. S. 60VEMNENT Plimil(6 OfFKE: I978-757-UO/6687 Region No. 5-11
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