EPA/530/SW-534
November 1976
s0V«d was*®
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An environmental protection publication (SW-88d) in the solid waste
management series. Mention of commercial products does not constitute
endorsement by the U.S. Government. Editing and technical content of this
report were the responsibilities of the Hazardous Waste Management Division
of the Office of Solid Waste Management Programs.
Single copies of this publication are available from Solid Waste
Information, U.S. Environmental Protection Agency, Cincinnati, Ohio 45268.
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PESTICIDE CONTAINER PROCESSING
IN
COMMERCIAL RECONDITIONING FACILITIES
This report (SW-86d) part of a study
conducted under EPA Demonstration Grant 5-G06-00222 was written
by WARREN S. STATON and JOHN G. LAMPERTON,
Environmental Sciences Center, Oregon State University, CorvaTMs, Oregon,
and edited by HARQLO R. DAY.
U.S. ENVIRONMENTAL PROTECTION AGENCY
1976
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CONTENTS
Page
Summary ^
Introduction *
Commercial Reconditioning ^
Container Processing *
Sampling Procedures for Pesticide Content Determination '
Extraction Procedures 7
Analysis Procedures '
Results and Discussion 8
References 21
Figures
Figure 1 Schematic Layout of a Typical Commercial
Drum Reconditioning Plant 4
Figure 2 Size, Shape, and Location of Wedges Cut
From 55 Gallon Drums •>
Tables
Table 1 Extraction and GLC Conditions Used in this Report 13
Table 2 Removal of Phorate Residues Fran 55 Gallon Drums 14
Table 3 Removal of Phorate Residues From 55 Gallon .
Drums Sampled Before and After Plant Processing
Table 4 Removal of Disulfoton From 55 Gallon Drums Using
Triple Rinse or Combined Processing
16
Table 5 2,4-D and 2,4,5-T Residuals in Processed
30 Gallon Drums
Table 6 Pesticide Residues in Processed Containers '8
Table 7 Number of Extractions Necessary to Remove Diazinon
Residues From 5 Gallon Can Wedges and Total
Diazinon Residues in the Containers ''
Table 8 Amount of Pesticide Rsnaining in Process solutions 20
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Drum Processing in Oonmercial Reconditioning Facilities
Summary
The drum reconditioning industry in the United States currently
reconditions many pesticide containers. Cost incentives to recondition
pesticide containers exist, but the problems of residual pesticide
and waste-water treatment require study. Reconditioning is accomplished
by two different methods — use of heated chemical solutions or
incineration followed by an abrasive treatment. Ihis study addresses
the effectiveness of chemical processing.
Drums formerly containing phorate, disulfoton, carbaryl, diazinon,
2,4-D, and 2,4,5-T were tested for pesticide content as received, after
triple-rinsing with water, and after plant processing. The residues
were measured from wedges cut from the containers, the weight of the
wedge was related to the total weight of the container; in turn, the pesticide
residue of the wedge can beirelated back to the total pesticide
content of the container.
In the case of phorate, 95 percent of the pesticide was removed
with both triple-rinsing and plant processing. Each independent process
removed about 60 percent. The amount removed by each process was
variable indicating possible processing inconsistencies. Similar
results were obtained from disulfoton drums. Triple-rinsing and
plant processing of chlordane containers leave about the same residue
by each method. As chlordane is water insoluble, a solvent pre-wash
is indicated. Over 90 percent of the phenoxy herbicides were removed
by triple-rinsing alone.
Tests on 5 gallon containers yielded about the same proportion
of residue as 55 gallon containers. Wash solution degradation is
discussed briefly.
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Drum Processing in Ooranercial Heoonditioning Facilities
Introduction
A well-established adjunct to production, manufacturing and
materials transport in the United States is the container reconditioning
industry. With one or more plants located in most large population
centers, the industry renews for resale a large volume of 30 and 55
gallon containers for a wide variety of industrial uses including oils,
chemicals, paints, adhesives and many other products. Prior to the
environmental movement, many types of pesticide containers were regularly
processed in these plants by the normal processing procedures.
With increases in costs of raw materials, labor, and energy, it
appears logical to expect that recycling of containers through such
facilities will increase in importance and that procedures will be
found to enable processing of pesticide containers in such facilities
in a safe and economical manner.
This paper covers one phase of several related which addressed
collection and impoundment, preprocessing, movement of containers to
commerical reconditioning facilities or to scrap, processing in
commercial facilities, washwater treatment, and container scrap off-gas
treatment.
Two main methods of container reconditioning are discussed here:
1. Processing by use of chemical solutions at elevated
temperature combined with mechanical abrading and reshaping
processes.
2. Processing by use of incineration and reshaping procedures
combined with sand-or-shot-blasting as required by container
condition.
Ihe first procedure lends itself to pesticides of high
solubility and low toxicity where residuals would not be critical
for non-food or feed uses.
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The second procedures lends itself well to pesticides of high
toxicity and/or low solubility if adequate controls are maintained on
incinerator temperatures such that pesticide materials are completely
combusted to elemental components.
The present project was designed to explore the potential of
commercial facilities to reduce pesticide residuals by use of the
first method above using chemical and mechanical means.
Specific objectives were:
1. To develop sampling and analytical methods for rapidly
determining the amount of residue 1n a container.
2. To determine the amount of residue remaining in containers
after processing by various methods.
3. To determine the concentration of pesticide in the wash
solutions.
4. To conduct preliminary investigations into wash solution
treatment processes.
Commercial Reconditioning
Facilities of the Vann Barrel Company of Portland, Oregon, were
utilized in the studies. This company, one of two recondltioners In
Portland has been in operation for many years and, while all types of
drums are processed, oil drums of several large oil companies make up the
bulk of the processing business. A schematic layout of the plant is
shown as Figure 1 with arrows showing the movement of drums through the plant.
Unit processes included in order of their use in this particular plant
are:
1. Inside caustic flush
2. Submergency in caustic solution (Solution 1-2X Sodium Hydroxide
solution at about 200°F.)
3. Spray rinse
4. De-dent
5. Chain interior
6. Straighten chines
7. Test for leaks
8. Inside steam-spray rinse
9. Inside syphone dryer
10. Spray-paint exterior
11. Storage
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SCHEMATIC LAYOUT
OF A
TYPICAL COMMERCIAL DRUM RECONDITIONING PLANT
VAHN BARREL COMPANY
PORTLAND, OREGON
ui
CXL
CO
EMPLOYEE'S
LUNCH
ROOM
OFFICE
RECONDITIONED
DRUM
STORAGE
t
CONVEYOR/"
INSIDE SYPHON
(DRYER)
/
INSIDE STEAM-SPRAY RINSE
CAUSTIC SUB-1ERGER 1
r * 4
O OO O
ooo o
_JCHIME
STRAIGHTNER
LEAK
BOILER
ROOM
OIL
STORAGE
'
STREET
(NOT TO SCALE)
Fig. i
UNPROCESSED
DRUM
STORAGE
INSIDE
CAUSTIC
FLUSH
TRUCK
UAblL
TREATMENT
FACILITIES 1
]|—1[ UNLOADING
UNPROCESSED
DRUMS
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Figure 2 Size, shape, and location of wedges
cut from 55 gallon drums.
Container Processing;
In most cases the drums were rinsed with water three times prior to
plant processing to simulate recommended field procedures. Pennwalt 91
and Oakite Ruststripper, commercial cleaning preparations, were both
tried as cleaning agents in the wash solutions. The amount of cleaning
agent in solution was adjusted to nake the wash solution 1 or 2% caustic.
The five gallon diazinon containers were run through the processes manually,
while all other containers were processed through the plant using the
normal mechanized equipment available for the larger drums.
Sampling Procedures for Pesticide Content Determinations;
Wedges were cut from the drums of the size shown and at locations
Indicated in Figure 2. Initially, the containers were sampled as
wedges with the weight of the wedge being related to the total weight
of the container in order to obtain the total amount of pesticide
In the container, as shown in equation 1.
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P" 'It (1)
Where:
Pc=pesticide content of a container
Pw=pesticide extracted from a set of wedges (grams)
W =weight of wedges
Wc=total weight of container
Subsequent investigation into concentration of pesticide at various sites
on the interior surfaces of the container revealed that 81% of the pesticide
residual was contained in the chime or rim of the. container. In order to
take this into account, the method of calculation shown in equation 2 was
used.
Pt • °-8lPwdt) + °-19 Pw
LW *«
Where:
Px=total pesticide in the container (grams)
Aj.=total interior surface area of the container
l_t=total length of rim of the container
Lwscombined length of rim of the wedges extracted
^combined area of the wedges
Further simplification of the calculations was achieved by using the
ratio of equation 1 and equation 2 to yield a correction factor "Z" as
shown in equation 3:
, pt (3)
Z = —
PC
This factor permits the weight of a standard sized wedge to be related to
the total amount of pesticide found in the drum as indicated by combining
equations 1 and 3 to yield:
pf <
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Z values were determined as 0.45 for the 30 gallon container and 0.61
for the 55 gallon container. The total amount of pesticide in each drum
was calculated according to equation 4 and was then used as the basts of
comparison in this study.
Extraction procedures. six wedges (F1gure 2j ^^ ^^ ^ ^
rin, by 5.3±0.3 inches lone, (side H) by 6.3 0.3 inches long (side S) were
placed chine down in a 4 liter stainless steel beaker with sufficient
solvent to cover the wedges. The solvents used for the various pesticides
are shewn in Table 1.
Analysis procedures. Chlordane, diazinon, disulfoton, methoxychlor, and
phorate extracts were evaportaed to near dryness and transferred with
hexane to an appropriate volumetric flask and diluted to volume. Usually
a second or third dilution was necessary for GLC analysis. The GLC con-
ditions for each pesticide are shown in Tabld 1. An electron capture
detector was used for the GLC analysis.
Carbaryl was analyzed using the method described by Karinen et al.
(1967). The dichloromethane (DCM) extracted wedges were evaporated to
500 milliliters and the extracted paint material allowed to settle out
overnight. A small aliquot (1-10 milliliters) was removed with a pipette
and evaporated to dryness in a 10 milliliter volumetric flask. The
residue was dissolved in 0.5 milliliter ethanol and the carbaryl and
1-naphthol were determined. Water samples were adjusted to approximately
pH 7 and extracted 3 times.
Dichloromethane extracts were analyzed for karathane by the method
of Kilgore and Cheng (1963). Water was extracted with DCM at pH3. The
DCM was carefully evaporated to dryness and the sample was then redissolved
in 4 milliliters of dimethylformamide for color development.
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Two milliliters of the 2,4-D and 2,4,5-T sodium hydroxide extracts
were acidified to pH 3 and extracted three times with 5 milliliters of
ethyl ether. The combined ether extracts were treated with a slight excess
of diazomethane, allowed to stand 10 minutes, and boiled on a steam.bath
to remove the excess diazomethane (yellow color). After appropriate
dilution the extracts were ready for 6LC. Water samples were adjusted to
pH 10-14 to allow hydrolysis and then acidified and extracted as described
above.
The total pesticide content of each drum was determined using equation
4 shown previously.
Results and Discussion
Phorate. Although used containers with residuals of several pesti-
cides were used, phorate was the only pesticide for which an adequate
number of drums were available for processing and analysis in a systematic
manner during this phase of the project. Two different procedures
were used in sampling the phorate drums. The first series of drums
was sampled such that ten randomly selected drums were sampled before
washing, ten were sampled after rinsing three times with clean water
(triple rinse), ten were sampled after plant processing, and ten were
sampled after triple rinsing and plant processing. The second procedure
involved sampling ten drums before washing and resampling the same drums
after rinsing and processing.
As may be seen from Table II, each process sionificantly removed
additional pesticide from the containers. Most pesticide was removed when
both triple rinsing and plant processing were employed. Using both
processes sequentially, more than 95% of the phorate was removed when
drums were in reasonably good condition. Either one of the processes used
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independently removed more than 60% of the phorate, and had much greater
variability than when both processes were used. Although the mean removal
was lower for plant processing only, neither process was significantly better
statistically, in cleaning ability than the other. The average amount
of phorate remaining in the dual processed drums was 1.27 grams per drum.
Assuming that all of the phorate remaining in the drum would be
dissolved in 55 gallons of a liquid contained in the drum upon reuse,
a concentration of 6.1 parts per million of phorate would result.
With the permissible toxicity level for this material taken into account,
drums in this condition would be suitable for non-food uses if precautions
were taken to ensure that they could only be used in this manner.
When results fron containers analyzed before and after is conpared
for each drum separately, greater variability and apparently less
cleanup occurred. The presence of one drum with only 37% decrease
in residue with the remaining 9 drums showing a 77-95% decrease indicates
that occasionally a drum is either not being properly processed or that
there .was considerably more residue within the chine that was unremovable
by the cleaning methods used.
The average residue removed was 89% leaving 2.63 grams of phorate in
each drum. This represents 12.6 parts per million of phorate in 55 gallons
of a possible secondary use liquid. A possible explanation for the overall
higher amount of phorate present may be due to the fact that these drums
were washed after the other two sets of barrels had been processed. Thus
the concentration of phorate in the water would have been high and some
cross-contanuLnatian from the processing solution could possibly have
resulted.
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Analysis of the rinse water showed that phorate, pnorate sulfoxide,
phorate sulfone, and traces of the oxygen analog were present in detectable
quantities. The majority of residue (about 80%) was found as phorate sul-
foxide.
Disjnfoton. Table IV shows the results when drums containing an
organophosphate similar to phorate were processed. Although the triple
rinse appears to have been more effective with disulfoton than phorate,
the percent removed for the combined processes is nearly the same for
disulfoton as for phorate. The fact that the containers were hand fed through
the process did not appear to make a significant difference.
Carbaryl. Chlordane, Diazinon, 2.4-D, and 2,4,5-T. Since a sufficient
number of containers swere not available to.perform the extensive oorparisons
that were possible with phorate and disulfoton, containers used for several
other pesticides were examined only for the amount of residue remaining in
the containers. From Tables V and VI it can be seen that significant quanti-
ties of pesticide still remain in some of the processed containers. The
amount of residue remaining likely depends upon whether the containers were
used for formulated material or technical grade material. The formulated pesti-
cides would tend to form stable emulsions while the technical material would be
removed only to the extent that it was soluble in the water, hydrolyzed by the
base present in process solutions, or physically washed from the container
independent of chemical action. Since the carbaryl containers contained an
emulsifiable concentrate and the chlordane containers were a mixture of
drums containing formulation type and technical qrade pesticides, it would
logically be expected that higher and more variable residue levels would
result from the chlordane containers. The additional fact that carbaryl is
readily hydrolyzed and chlordane is not probably accounts for the lower carbaryl
residue levels,
10
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Triple rinsing of technical grade chlordane containers decreases the
amount of chemical present to essentially that obtained by plant processing.
High residual levels after both types of processing, particularly of drums
used for technical grade chlordane, indicates that the material is highly
insoluble in aqueous solutions and is susceptible to only slight hydrolysis
as mentioned above. In such cases of low solubility and chemical activity, pre-
processing of containers with appropriate solutes prior to release from point
of use appears to be indicated. This does not hold true, however, for 2,4-D
and 2,4,5-T drums as shown in Table V. Processing through the reconditioning
plant removed over 90% of the 2,4-D residue remaining after triple rinsing.
Although 2,4-D and 2,4,5-T do not present the toxicity problem to
humans which phorate, disulfoton, and diazinon do, other problems resulting
from the phytotoxicity of these compounds would limit the reuse of these
containers. On the. basis of the mean residual in a container, a concentration of
1.26 parts per million would result if all the 2,4-D residues were dissolved
in 30 gallons of material in the drum. Considering the variation among the
samples, concentrations of 2 parts per million 2,4-D and 2.5 parts per million
2,4,5-T might be expected in a solution resulting from re-use of a triple
rinsed and processed drum. This amount of 2,4-D might be sufficient to
cause damage to certain sensitive crops if applied after diluting up to four
times.
The feasibility of cleaning 5 gallon containers in a manner similar to
that utilized for 30 and 55 gallon drums was investigated using empty 5 gallon
diazinon cans. The amount of residue remaining in the containers is shown
in Table VII. Residues in the processed 5 gallon containers were approximately
equivalent to those found for the other organophosphates In experiments with the
larger drums. On the average, the cleaned 5 gallon cans had a residual of 12.8 parts
11
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per million diazinon, while cleaned 55 gallon drums contained from 5 to 13
parts per million prorate.
The effectiveness of the extraction procedure used was also determined
using the diazinon cans. From Table VII it can be seen that practically all
of the diazinon is extracted in two extractions. Less than 0.3% could be ex-
tracted with a third extraction. Thus, only two extractions of the wedges
were necessary.
Process solutions. Table VIII summarizes the results from analyzing
several of the wash solutions used in processing the containers. Pesticides
which are easily broken down in.1% caustic show significantly less residue
in the wash solutions than the more stable pesticides. Only the acid was
measured in the case of 2,4-D and 2,4,5-T. Since the 2,4-D ester was
found to hydrolyze completely in the wash solution within 4 hours, the acids
are all that one would expect to be present in the wash solution.
Experiments using diazinon .showed its half-life in the 1% caustic wash
solution to be 21 days. Carbaryl in the 1% caustic solution is completely
hydrolyzed within 30 minutes. Disulfoton wash solutions contained unidentified
pe^ks (possible breakdown products) when they were analyzed. As has been
already noted, the phorate wash was mostly in the"form of phorate
sulfoxide. Since some hydrolysis products are not extracted with hexane or
dichloromethane, they would not be observed using the methods employed here.
12
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TABLE I Extraction and GLC Conditions Used in this Report
Retention
Temp Flow Rate time, Rt
Pesticide
Carbaryl
Chlordane
Diazinon
Disulfoton
2,4-D and 2,4, 5-T
Karathane
Methoxychlor
Phorate
Extraction Solvent
GC
dichloromethane
ethyl
ethyl
ethyl
4-6%
ether
ether
ether or acetone
NaOH
5'
5'
8'
6'
x 1/4"
x 1/4"
x 1/8"
x 1/8"
dichloromethane
ethyl
ethyl
ether
ether or acetone
6'
6'
x 1/8"
x 1/8"
Column
OC
ml/min
minutes
Colorimetric
glass
glass
glass
glass
10%
10%
7%
7%
OV-1
OV-1
OV-1
OV-1
245
240
200
170
60
30
25
25
6-18*
3.5
3.5
1.6, 2.8
Colorimetric
glass
glass
7%
7%
OV-1
OV-1
245
185
60
25
10
2.2
Multiple peaks
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TABLE II Removal of Phorate Residues From 55 Gallon Drums
Unprocessed Triple rinsed
drum residual, drum residual,
qrams grams
Mean
Percent
removed
Standard
error
59.8
24.8
25.0
32.6
46.6
64.9
15.9
44.9
36.9
38.2
39.0
--
24.1
4.10
3.98
10.25
7.97
13.62
6.42
7.98
9.05
15.20
7.75
8.63
77.9
1.33
Plant processed Combined
drun residual, residual,
qrams grams
1.88
0.80
5.61
7.33
8.37
3.99
7.49
0.82
7.39
3.23
4.69
88.0
.857
0.389
1.362
0.937
0.335
0.776
0.696
2.072
1.912
2.117
2.061
1.266
96.7
.0527
Triple rinsed and plant processed
14
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TABLE III Removal of Phorate Residues From 55 Gallon Drums
Sampled Before and After Plant Processing
Before process, After process Estimated percent
Drum residual .arams
A
C
D
E
F
G
H
I
J
K
Mean
Standard,,
error S^
n
Confidence
interval 953!
14.38
17.19
17.34
13.22
12.66
39.60
58.56
50.78
45.10
45.45
31.43
32.63
25,72-37.14
residual grams
3.30
10.82
3.24
2.10
2.11
2.18
3.56
2.85
2.14
2.18
2.63*
0.04*
2,16-3.10*
Reduction
11.08
6.37
14,10
11.12
10.55
37.42
55.00
47.93
42.96
43.27
removal
77.1
37.1
81.3
84.1
83.3
94.5
93.9
94.4
95.3
95.2
88.8
*Drum "C" excluded
15
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TABLE IV Removal of Disulfoton from 55 Gallon Drums
Using Triple Rinse or Combined Processing
Unprocessed
drum residual,
Triple rinsed Processed
drum residual, drum residual,
Mean
Standard
error S^
n
Confidence
Interval 95%
Percent
removed
grams
18.2
17.8
19.5
19.7
18.8
0.222
17.3-20.3
—
a rams
1.255
1.726
0.296
0.678
0.375
.0.114 .
0.741
0.065
0.084-1.298
96.0
grams
0.315
0.364
0.445
0.148
0.176
0.046
0.249
0.0038
0.009-0.406
98.7
* Triple rinse and plant process
16
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TABLE V 2,4-D and 2,4,5-T Residuals in Processed 30-Gallon Drums
Residual 1n drums *
triple rinsed only
2,4-D
grams/drum
1.01
10.91
0.861
6.24
2,4,5-T
grams/drum
3.25
21.71
1.67
2.25
Residual in drums +
plant processed only
Residual in drums *+
triple rinsed and plant processed
2,4-D
grams/drum
0.300
0.900
0.532
0.432
0.732
0.432
2,4,5-T
grams/drum
0.322
1.832
0.966
0.720
1.480
2.106
2,4-D
grams/drum
0.077
0.132
0.251
0.106
0.138
0.128
0.054
0.216
0.118
0.208
0.093
0.139
0.208
0.093
0.139
0.208
0.104
0.163
0.138
2,4,5-T
grams/drum
0.061
0.135
0.278
0.123
0.188
0.158
0.083
0.326
0.134
0.267
0.154
0.204
0.293
0.158
0.255
0.189
Mean 4.76*4.80 7.22+9.68
Residual ~"
0.555+0.222
1.238+0.685
0.142+0.054
0.188+0.077
OakiteR caustic processing material.
+>ennwalt 91R caustic processing material.
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TABLE VI Pesticide Residues in Processed Containers
Pesticide
Mean
Range
Standard
error
Number
of drums
Carbaryl
grams/drum
0.105
0.055-0.148
0.00013
6
Chlordane
^rams/drum
3.10
1.25-8.34
1.17
6
Chlordane
grams/drum
2.44
0.290-10.78
0.649
17
Triple rinsed
Triple rinsed and plant processed
Technical grade
18
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VD
TABLE VII Number of Extractions Necessary to Remove Diazinon Residues
from 5 Gallon Can Wedges and Total Diazinon Residues in the
Containers.
Sample
2-7-A
2-7-B
2-7-C
2-7-D
2-7-E
2-7-F
2-7-G
2-7-H
2-7-1
first
extraction
wedqes, prams
0.113
0.030
0.055
0.081
0.090
0.099
0.026
0.046
0.015
second*
extraction
wedges, grams
0.013
0.003
0.005
0.012
0.001
0.003
0.001
0.011
0.002
Third
extraction
wedqes, qrams
0.0003
<.0001
<.0001
0.0003
<.0001
<.0001
<.0001
<.0001
<.0001
Total
extracted
wedges, grams
0.126
0.033
0.060
0.093
0.091
0.102
0.027
0.057
0.017
Total
extracted
drum, grams
0.455
0.119
0.217
0.336
0.329
0.368
0.097
0.206
0.062
Mean 0.243+0.136
0.0021
Interval
(955!.) 0.138-0.348
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TABLE VIII Amount of Pesticide Remaining in Process Solutions
Pesticide
Phorate
Disulfoton
Chlordane
Carbaryl
(1-naphthol)
2,4-D
Grams
pesticide
84.01*
0.183*
4222. 4+ *
28.73+
621.5*
Number
containers
30
48
22
11
38
Grams generated
per container
2.80
.004
191.93
2.61
16.35
Plusher and submerger
+
Plusher only
Technical grade
20
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BIBLIOGRAPHY
1. Goulding, R.L. Waste pesticide management; final narrative report,
July 1, 1969-June 30, 1972. Corvallis, Oregon State,University,
Environmental Health Sciences Center, Aug. 1973. 81 p., app.
{Unpublished report.)
2. Karinen, J.F., J.6. Lamberton, N.E. Stewart, and UC. Terrt'ere.
Persistence of carbaryl in the marine estuarine environment;
Chemical and biological stability in aquarium systems. Journal of
Agricultural and Food Chemistry, 15(1):148-156, Jan.-Feb. 1967.
3. Kilgore, W.W., and K.W. Cheng. Extraction and determination of Karathane
residues in fruits. Journal of Arglcultural and Food Chemistry. 11(6):
477-479, Nov.-Dec, 1963.
M01347
21
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