United States
Environmental Protection
Agency
Environmental Monitoring and Sup
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S4-82-023 June 1982
Project Summary
\ ''
Determination of
Pesticides and PCBs in
Industrial and Municipal
rWe*£tewaters
r ^ v'
?j \iilbhnD.MillarandRichardE.Thomas
'
Steps in the procedure for the
analysis of 25 chlorinated pesticides
and polychlorinated biphenyls were
studied. Two gas chromatographic
columns and two detectors, electron
capture and Hall electrolytic con-
ductivity, were evaluated. Extractions
were performed with two solvents—
dichloromethane and 15% dichloro-
methane in hexane—at three pHs to
determine extraction efficiencies. The
effects of storage for seven days, in
the presence of residual chlorine, at
two temperatures were determined.
Florisil and alumina were compared as
adsorbents for the clean up of extracts.
Recoveries of the substances from
clean water and wastewater were
measured, and assessments of ac-
curacy and precision were made.
The method is satisfactory for the
analysis of clean waters and waste-
waters having a relatively low back-
ground of interferences. However, it
does not work well against medium to
high levels of background interfer-
ences produced by substances that
are electron capture sensitive, es-
pecially halogenated ones. Use of the
Hall detector is indicated when non-
halogenated electron capture sensitive
interferences are a problem, even
though some loss in sensitivity will
occur. When halogenated interfer-
ences are overwhelming, altered gas
chromatography conditions and
columns, such as temperature pro-
gramming and columns which produce
better resolution than the ones studied
in this work, will be required.
This Project Summary was devel-
oped by EPA's Environmental Moni-
toring and Support Laboratory,
Cincinnati, OH. to announce key
findings of the research project that is
fully documented in a separate report
of the same title (see Project Report
ordering information at back).
Introduction
Under provisions of the Clean Water
Act, the Environmental Protection
Agency is required to promulgate
guidelines establishing test procedures
for the analysis of pollutants. The Clean
Water Act Amendments of 1977
emphasize the control of toxic pollutants
and declare the 65 "priority" pollutants
and classes of pollutants to be toxic
under Section 307(a) of the Act. This
report is one of a series that investigates
the analytical behavior of selected
priority pollutants and suggests a
suitable test procedure for their mea-
surement.
-------
The substances studied in this effort
were:
1. a-BHC
2. 0-BHC
3. <5-BHC
4. Heptachlor epoxide
5. DDE (p,p'(
6. ODD (p,p')
7. DDT (p.p')
8. Endosulfan sulfate
9. x-BHC
10. Heptachlor
11. Aldrin
12. Endosulfan I
13. Dieldrin
14. Endrin
15. Endosulfan II
16. Endrin aldehyde
17. Chlordane
18. Toxaphene
19. PCB-1016
20. PCB-1221
21. PCB-1232
22. PCB-1242
23. PCB-1248
24. PCB-1254
25. PCB-1260
The study was conducted in two
phases. In Phase I, work was conducted
with clean water and was intended to
provide information that would give
direction to Phase II work, conducted on
actual wastewaters, and serve as a
comparison base for the information
developed.
The ultimate objective was to develop
a method, having a maximum of ap-
plicability, that could be published in the
Federal Register and carried out in most
analytical laboratories.
Other objectives included the devel-
opment of accuracy and precision
information, procedure variations as
required by a particular wastewater,
and the maximization of using common
sample treatment steps for all the
categories of priority pollutants.
Phase I
Gas Chromatography
The 25 substances can be gas
chromatographed very well. Sensitivity
quantities producing a response 10X
noise level for the electron capture
detector range from 1 to 380 picograms.
Sensitivity quantities for the Hall
electrolytic conductivity detector are
roughly 10 to 100 times greater than
this. The 16 single compound pesticides
can be fully resolved if chromatographed
in two groups of eight each. The PCBs
are best chromatographed individually,
but several combinations can be ade-
quately chromatographed for some
analytical purposes.
The primary gas chromatography
column used in this work, 1.5% SP2250
+ 1.95% SP 240} on 100/120 mesh
Supelcoport, is preferred on a general
use basis over 3% OV-1 on the same
solid support. In limited situations,
however, it is possible that either the
OV-1 column or columns with other
liquid phases, such as OV-17, may
perform as well or better than the
primary column.
A comparison of detectors showed
that the Hall electrolytic conductivity
detector is more discriminating than the
electron capture detector, and it should
be used as the primary detector, or used
as an auxiliary detector when non-
halogenated electron capture sensitive
materials present interference problems.
Extraction Study
The extraction study was initiated to
determine the recoveries of the 25
substances of interest from clean water
at pH 2, 7 and 10 using 15% dichloro-
methane (DCM) in hexane and 100%
DCM as the extracting solvents.
The water used in the extraction study
is a naturally buffered well water
obtained from the Southwest Research
Institute supply line prior to chlorina-
tion. Samples of this water were
collected and transported to the labora-
tory in empty solvent bottles which had
previously contained Burdick and
Jackson solvents. The pH of the un-
treated water is close to 8. Adjustment
to the required pHs was accomplished
by adding strong acid or base.
Extraction of the pesticides from
clean water at parts per trillion con-
centrations when the pH was 2,7, or 10,
was generally 80% or better using 1 5%
DCM in hexane or pure DCM as the
extracting solvent. When heptachlor
and aldrin were used, however, extrac-
tion percentages were generally 50 to
75%. Occasionally, one of the solvents
at a particular pH gave a more efficient
extraction than did the other solvent-pH
combinations, although the improve-
ments were not great enough to
demand the particular combination be
adhered to exclusively. Under the same
extraction conditions, PCB-1242, PCB-
1248, PCB-1254, and PCB-1260 at low
parts per billion levels were extracted
with 90% or better recoveries. At similar
levels, PCB-1016, PCB-1221, and PCB-
1232 were extracted with adequate
efficiency, but the recoveries recorded
were occasionally as low as 60%.
No clear advantages have been noted
for either solvent studied in this work. In
the interest of commonality, either
solvent may be chosen without an
intolerable loss of efficiency occurring
during sample extraction. The pH of the
water at the time of extraction is not of
substantial concern. However, if the
substance being sought is designated
beforehand, a slight advantage may be
available in some instances by consult-
ing the statistical analysis data for
combined pH-splvent effects on the
extraction.of that particular substance.
Preservation Study
The preservation study was conducted
to determine the effects of a 90-day
storage period, at various conditions, on
the recovery of the 25 substances of
interest from dosed water samples. Each
sample consisted of one quart of water
dosed with one of the eleven groups, as
in the extraction study. Two replicates
for each of twelve conditions of pH,
temperature and residual chlorine were
prepared for each group in the following
model (Table 1):
The 2 ppm residual chlorine level was
obtained where required, by adding 160
mLof Mallinckrodt sodium hypochlorite
analytical reagent (5% minimum avail-
able Cl). Storage containers were one-
quart, flint glass, round, narrow-mouth
bottles closed with aluminum foil-lined
caps. A sample was prepared by filling
the bottle about two-thirds full with pH
adjusted water, adding 160 mL sodium
hypochlorite when required, swirling
vigorously, adding the 100 mL dosing
solution into the vortex, and combining
the remainder of the pH adjusted water
with the solution in the bottle while it
was still swirling. The bottle was capped
immediately and stored in a closed
cardboard box at 4°C or 24°C. Care was
taken not to slosh the bottle contents
onto the aluminum lining the cap after
closure.
The well water was dosed with a
quantity of substance inversely related
to the detector response for the sub-
stance. Thus, a-BHC was spiked at the
20 parts per trillion level and toxaphene
at the 4 ppb level. Other substances
were dosed at levels in between these
extremes. Extraction was performed
with 15% DCM in hexane and with
100% DCM at pHs of 2. 7 and 10. The
most serious problem encountered was
the presence of interfering peaks in
chromatograms of blanks. The varying
magnitude of these peaks made sub-
traction of a constant blank usually not
-------
possible. Occasionally, work had to be
repeated.
At the concentrations used, some
conditions of the preservation study
produced pronounced effects on the
substances. Deleterious effects were
found to occur with about half of the 25
substances at some of the 12 combina-
tions of pH, temperature, and residual
chlorine levels studied However, 23 of
the substances were stored in the dark
for seven days at 4°C, under neutral or
acidic pH, and in the presence and
absence of two ppb residual chlorine
with the only losses suffered being of a
tolerable magnitude. Aldrin sustained a
15 to 20% loss at acid or neutral pHs in
the presence of chlorine. Endosulfan
sulfate losses were 90% or more under
all conditions of storage at 230 parts per
trillion concentration in clean water. In
the storage and recovery tests involving
wastewater, however, endosulfan
sulfate was dosed at the 15 ppb
concentration and no large losses were
observed.
Storage of samples before extraction
should be at a neutral to an acidic pH
and at 4°C. Storage periods of up to
seven days' duration do not produce
significant decreases in concentrations,
except for endosulfan sulfate in con-
centrations of parts per trillion. For
determinations at these levels, samples
should be extracted immediately after
sampling. If aldrin is to be determined,
residual chlorine, if present, should be
eliminated before storage of samples.
Liquid-Solid Column
Chromatography
Nearly 100% recoveries where
achieved during column chromatogra-
phy of substances applied to fully
activated Florisil PR or alumina mixed
with 10% by weight water. Elution
patterns of the substances from the
Florisil were more desirable than from
the alumina. In application studies with
wastewaters, the Florisil was slightly
superior to the alumina in clean up of
extracts.
Florisil
The Florisil clean up column was
prepared by gently packing Florisil PR,
which was taken directly from storage
at 130°Cfora minimum of 24 hours, toa
height of 10 cm (about 21 grams) in a
400mm x 25mm (OD) glass column
containing a course fritted disc and
fitted with a Teflon stopcock. A layer of
sodium sulfate 1-2 cm in height was
added. The column was prewetted with
Table 1 .Experimental Model for Preservation Study
4°C
24° C
0 ppm Cl
2 ppm Cl
0 ppm Cl
2 ppm Cl
pH2
pH7
pH 10
2
2
2
2
2
2
2
2
2
2
2
2
60 mL of hexane and drained to the top
of the sodium sulfate. Next, a 5 mL
volume of hexane containing a dose of
one of the groups was put on the
column, which was again drained to the
top of the sodium sulfate. Elution was
then performed using 200 mL volumes
of 6, 15 and 50% ethyl ether in hexane,
with each 200 mL elution fraction
received in a Kuderna-Damsh flask.
Each fraction was concentrated to a 10
mL final volume and an appropriate
volume was injected into the gas
chromatograph.
Alumina
Add 10mLwaterto90gramsalumina
(Woelm N-Super I), as purchased in a
jar. Cap the jar, shake until the mixture
is flowing smoothly, then let stand 24
hours before using. Slurry 22 grams of
the prepared alumina in enough hexane
so it can be poured into a 400mm x
25mm OD glass column with a coarse
fritted disc and a Teflon stopcock. Settle
the alumina with gentle tapping on the
glass column and add a layer of sodium
sulfate 1-2 cm in height. Wash the
column with 20 mL hexane and add the
dosed hexane which should be about 5
mL in volume. Successively elute with
40 mL hexane, 110 mL hexane, 100 mL
50% ethyl ether containing 2% ethyl
alcohol in hexane, and receive each
fraction in a Kuderna-Danish flask.
Concentrate the fractions to final
volumes of lOmLandinjectappropnate
quantities into the gas chromatograph.
Evaluation of Results
Recoveries from both columns are
excellent. Elution times with the alumina
column are shorter than those with the
Florisil column. However, the single
compound pesticides, chlordane, and
toxaphene, are more frequently found in
two fractions when using a alumina
column than when using a Florisil
column. Thus, processing and analyzing
additional fractions, as would be the
case with alumina, would likely be more
time consuming'than would be the
longer elution times with Florisil. Since
more components are recovered near
the 100% level in the first fraction
(Florisil), this advantage appears to
more than offset the less significant
advantages of the alumina. Further-
more, Florisil may be stored as received
in a 13P°C oven for indefinite periods of
time and still be usable. The alumina as
received must be cautiously deactivated
to Activity IV (10% water by weight) and
then protected with care until used.
How long Activity IV alumina may be
held before use is not known. However,
it appears to be a reasonably long
period, perhaps two weeks or longer.
Phase II
Wastewater Application
With the assistance and approval of
the project officer, five wastewaters
were procured and analyzed. The
sources of these wastewaters and the
results of the analyses are given below.
All samples were put into one-gallon
glass bottles which had previously
contained Burdick and Jackson "distilled
in glass" solvents, suitable for pesticide
residue analysis. Sample sizes ranged
from 20 to 24 gallons. All samples were
shipped by air, unrefrigerated. Time in
shipment was five days for Wastewater
1 and about two days for the others.
Upon receipt at Southwest Research
Institute, the samples were pooled in a
25-gallon stainless steel vessel, where
the pH was adjusted to 3-4, as required,
with concentrated sulfuric acid.'The
samples were then returned to the
bottles in which they were shipped and
stored at 4°C until used.
Analysis of Wastewaters
In order to develop improvements
upon the method and to provide base
data for the dosing and recovery
experiments, as well as the accuracy
and precision evaluations to follow,
each wastewater was analyzed in
triplicate for each substance of interest
in this program. As an arbitrary working
device and to allow for small errors
attendant to injection, flow control,
temperature control, and so on, the
coincidence of retention times was
considered for identification purposes
to be anything within 0.03 minutes.
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Dosing of Wastewaters and
Recovery Analyses
In order to accumulate data for
accuracy and precision evaluations,
each group was put into six, one-liter
portions of each wastewater, one group
at a time. Three of these dosed samples
were immediately analyzed while three
were stored in the dark at 4°C for seven
days in sealed, glass containers. The
dosed quantities were keyed to the
specific response of the substance to
electron capture detection, ranging
from 1 yug/L for the substances giving
the highest response, to 200 fjg/L for
toxaphene, except where interfering
background required increase of the
quantity. Except where noted to the
contrary, extraction, clean up and GC
analysis of the extracts were as given in
earlier sections of this .report.
Wastewater 1
This wastewater was sampled by
personnel of the Surveillance and
Analysis Division, USEPA, Athens,
Georgia and was identified there as Hl-
003 The pH as received was between
7.5 and 8. The wastewater was light
yellow to light orange in color, free from
solids and had a mild odor, reminiscent
of pine oil with a sweet overtone. The
plant producing the sample manufac-
tures toxaphene and other organic
materials, and it was understood that
this effluent was"derived from all the
plant operations, and not from the
toxaphene unit. This was due to the
toxaphene plant's effluent treating unit
being "down" on the day of sampling,
and as a result no effluent was being
discharged from it at that time.
As a preliminary step to the analysis
of Wastewater 1, extracts were cleaned
up with Florisil and alumina. Of the
three fractions taken from each column,
alumina produced the cleaner initial
two fractions but a much dirtier third
fraction. Since six single compound
pesticides were determined in the third
fraction from the alumina, but only two
in the third fraction were determined
from the Florisil, Florisil was the better
overall choice and was subsequently
used in all work with Wastewater 1. A
comparison with standards rules out all
of the pollutants of interest in this
program, except heptachlor and endo-
sulfan II and PCB-1242. The presence of
PCB-1242 is more questionable than
the other two substances, since only six
of the nine peaks being followed in the
analysis of this substance were present,
and the amount present, as indicated by
Table 2. Ranges of Recoveries, Wastewater 1
Ranges of Recoveries, %, avg.
Single compound pesticides
Chlordane (6 peaks}
Toxaphene (8 peaks)
PCB-1 254 (7 peaks)
PCB-1 01 6 (8 peaks)
PCB-1 260 (11 peaks)
PCB-1221 (7 peaks)
PCB-1 232(10 peaks)
PCB-1242 (9 peaks)
PCB-1 248 (7 peaks)
Zero
90 -
88 -
99 -
93 -
86 -
91 -
98 -
89 -
92 -
98 -
Time
110
106
105
98
97
102
117
134
101
101
7 Days' Storage
90 -
93 -
96 -
102 -
98 -
97 -
97 -
92 -
93 -
100 -
99
109
106
105
106
112
101
96
97
103
each peak, was not a constant value.
This is strong, but not conclusive
evidence that PCB-1242 is not present.
However, if the substance present is
PCB-1242, the amount indicated is less
than two ppb, and the other two sub-
stances are at 20 and 40 parts per
trillion, respectively
The dosing and recovery experiments
for Wastewater 1 went smoothly. It is
estimated that the dosing quantities
could have been reduced to 25% of the
quantities used with analytical results
remaining satisfactory in most instances.
The greatest difficulties occurred with
interferences for one or two early
eluting peaks of PCB-1221 and PCB-
1232. If these peaks had been elimi-
nated from the analyses, adequate
peaks would have remained for analyti-
cal purposes, and the ranges given for
these substances would have been
narrowed. Recovery ranges were as
follows in Table 2.
Wastewater 2
Wastewater 2 was sampled by per-
sonnel of the Eastern District Office,
USEPA, Westlake, Ohio No information
was supplied as to the source or
character of this sample. The sample as
received was amber in color, free from
solids, had a urinelike odor, and had a
pH of 4.
Despite the absence of substances of
interest, the substances which were
present provided many interferences in
the spiking and recovery experiments.
Due to the interference problems,
especially from the substances eluting
from the GC column during thefirstfour
minutes, a considerable effort was
made to identify the source of these
interferences, with the hope that such
identification would suggest approaches
for their removal. The presence of
elemental sulfur was strongly sus-
pected. Treatment of first fractions of
extracts with elemental mercury began,
but the results were erratic. Careful
drying of the extracts, addition of a
mercuric salt, addition of acid-washed
copper, and prolonging the agitation
period were without consistently bene-
ficial effects.
During concentration of the extracts
in the Kuderna-Danish apparatus, a
deposit of yellowish needle crystals and
a gummy residue were noted. Infrared
spectroscopy examination suggested
that pentachlorophenol might have
been present.
GC/MS analysis of the concentrated
extract indicated the presence of
naphthalene, methyl napthalene, two
dichlormated compounds, 2-methyl-
thiobenzothiazole, phthalates, dioctyl
adipate, anthracene, and two hydro-
carbons. No pesticides were found.
The difficulties with this wastewater
were so great that dosing and recovery
experiments were not completed for
several of the pesticides and PCBs. An
erratic response to clean up, especially
with mercury, produced inconsistent
background values in many instances
The greatest difficulties occurred within
the first four minutes after injection. It
was not unusual to experience no
reduction in the interferences in un-
dosed wastewater replicates treated
with mercury, and yet, find substantial
reductions in interferences in the dosed
replicates, or vice versa An impasse
was reached and work with this waste-
water was set aside so attention could
be given to the other wastewaters.
Wastewater 3
Wastewater 3 was procured by
Southwest Research Institute-Houston
personnel, and as received, had a mildly
bad odor, a cloudy appearance, and a pH
near 7. It was the final chlorinated
effluent from the Northside Treatment
plant in Houston, which treats both
residential sewage and industrial plant
effluents
4
-------
The analyses of three, one-liter
replicates suggests the presence of DDE
at 22 parts per trillion, dieldrin at 38
parts per trillion and chlordane at about
600 parts per trillion. Although only two
peaks are shown as matching with
chlordane, they are the major peaks for
the substance. The lesser peaks might
not be detectable in this matrix at this
level. Five of the ten peaks matched the
standard for PCB-1232, but the amount
present, as indicated by each peak, was
quite variable. This is strong evidence
against its presence, and therefore,
PCB-1232 was not considered to be
present. The difficulties with this
wastewater included emulsion forma-
tion and erratic response to clean up
with mercury. The latter difficulty,
although not as pronounced as with
Wastewater 2, persisted throughout the
work with this sample. As with Waste-
water 2, the undosed replicates were
more erratic as a rule than the dosed
ones. As a consequence, the back-
ground values were from replicates not
exposed to mercury, and the dosed
replicates all received clean up with
mercury. In some instances, this
resulted in recovery percentages which
were perhaps too low by a few per-
centage points Aldrin, DDE, DDT, and
toxaphene suffered the highest losses
during the seven-day storage period,
with losses ranging from 12 to 17%.
Recovery ranges were as follows in
Table 3.
Wastewater 4
Wastewater 4 was procured by
Southwest Research Institute, and was
from one of the influent streams in a
highly industrialized area of the city,
flowing to the Northside Treatment
Plant in Houston. As received, this
sample had a rank sewage odor, some
solid material, a cloudy appearance, and
a pH near 7
Flonsil was used to clean up the
extracts, and was followed by agitation
of the first fractions with mercury.
Emulsions formed as with Wastewater
3 and were treated as reported for that
wastewater.
Treatment with mercury produced
somewhat erratic reductions of inter-
ferences Six replicates were treated.
The last two were subjected to an
increased amount of violent agitation
with the vortex tube agitator as com-
pared to the first four. This resulted in
more uniform and lower analytical
values in the data derived from first
fractions. Comparison of retention
Table3. Ranges of Recoveries, Wastewater 3
Ranges of Recoveries, %, avg
Single compound pesticides
Chlordane (6 peaks)
Toxaphene (8 peaks)
PCB-1 254 17 peaks)
PCB-1 01 6 (8 peaks)
PCB-1 260 (11 peaks)
PCB-1 221 (7 peaks)
PCB-1 232 (10 peaks)
PCB-1 242 (9 peaks)
PCB-1 248 (7 peaks)
Zero Time
79-102
78-89
89-99
89-94
92-99
95-146
86-97
81-171
79-87
83-91
7 days' Storage
83-106
98-105
83-88
91-95
92-98
88-92
91-93
85-108
109-114
91-96
times with standards indicates the
presence of DDE at 31 parts per trillion,
heptachlor at 119 parts per trillion,
dieldrin at 32 parts per trillion, and
chlordane at 1.4 ppb.
As mentioned earlier, Wastewater 4
was quite similar to Wastewater 3, so
for this and other reasons, only certain
substances were dosed and recovered.
This was performed at zero time, only.
There were no unexpected problems
met, and mercury clean up was less
erratic than with Wastewater 3 and
with earlier undosed replicates of this
wastewater. Treatment of an extract
with BioBeads SX-2 was without bene-
ficial effects.
Wastewater 5
This sample was taken by Southern
Research Institute personnel, through
arrangements made by the EPA, from
the final effluent stream from a pesticide
manufacturing plant in Memphis,
Tennessee. As received, this effluent
was clear, had a chemical odor, and a pH
around 3.
Emulsification was not a problem.
Column clean up was carried out with
Florisil after a preliminary comparison
with alumina showed no advantage
resulting from the use of alumina.
When this wastewater was analyzed, it
was found that Florisil afforded a
slightly better, although inadequate,
clean up than did alumina. In another
experiment, the first fraction from
Florisil of a dosed sample extract was
exchanged into DCM and applied to a
22mm x 31cm column of BioBeads SX-
2. During elution of this column with
DCM, several fractions were collected
and analyzed. There was no improve-
ment in the separation of the interfering
materials from the dosed pesticides.
This wastewater had a very high
background of substances which were
electron capture sensitive compared to
the other four wastewaters. However,
most of the substances producing peaks
are not substances of interest on this
program. Comparison of retention times
with standards indicates the presence
of heptachlor at 6.6 ppb. GC/MS
examination of the first and second
fractions of an extract indicated that
nearly all of the substances are
chlorinated but only the presence of
heptachlor was confirmed.
This wastewater represented a seri-
ous challenge to this program. It was an
effluent from a pesticide manufacturing
plant, and it contained numerous non-
priority, chlorinated pollutants which
interfered with the analyses for many of
the priority pollutants which are the
subject of this program.
The ability of concentrated sulfunc
acid and fuming sulfuric acid (7.5%) to
extract interfering materials from a
hexane solution of the firstfraction from
Flonsil was tested. Concentrated sulfuric
acid removed a small, but insignificant,
amount of these materials, and the
fuming acid was no better.
By operating the GC on a temperature
program, advantages were realized with
some of the substances, for example,
single compound pesticides and chlor-
dane This technique was applied to
analyze recovered doses of y-BHC,
heptachlor, aldrin, endosulfan I, dieldrin,
endrin, endosulfan II, endrin aldehyde,
and chlordane from this wastewater at
zero time. The temperature was pro-
grammed from 160° to 200°C at 4° per
minute. Only dieldrin defied determina-
tion completely. Recoveries for the
other components ranged from 62 to
107%. Endrin determination gave more
reasonable values under isothermal
conditions that programmed conditions.
Peak height measurements produced
the more reasonable recovery values.
Recoveries ranged from 57 to 109%. It is
noted that the 57% value for the
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heptachlor component of chlordane
checks fairly well with the 62% recovery
obtained for heptachlor.
Dosing and recovery were carried out
at zero time only. PCB-1242 and PCB-
1254 were spiked into the same
samples and measured using the
procedure in ASTM Method D3304-77.
In this method, alkaline hydrolysis
followed by extraction with concen-
trated sulfuric acid is performed to
reduce non-PCB interferences. Some
interfering peaks remained in the
treated fraction, especially in the early
part of the chromatogram. Three such
replicates were dosed, extracted,
treated, and analyzed. The data show
that peaks 1 and 5 in PCB-1242 were
obscured by interferences to the extent
they could not be read. Recoveries of
other components ranged from 22 to
85%. The poor recoveries indicated by
the other PCB-1242 peaks, except for
peak 6, are probably the result of poor
quantitation, as a consequence of
interferences, rather than poor extrac-
tion. This view is supported by the fact
that the indicated recoveries for PCB-
1254 are much higher and uniform in
values.
The other PCBs should give compar-
able results. Those which elute early
(PCB-1016, PCB-1221, PCB-1232,
PCB-1248) will be analyzed with greater
difficulty and less precision and accu-
racy, probably, than the other late
eluter, PCB-1260, in Wastewater 5.
Discussion
In Phase I, endosulfan sulfate was
found to disappear almost entirely from
dosed clean water replicates stored for
seven days at 4° and 24°C. In Phase II,
no similar inordinate disappearance of
endosulfan sulfate occurred in the
replicates of Wastewaters 1, 2 and 3
during storage at 4°C.
Only a few of the 25 substances were
found in the five wastewaters analyzed.
Endrin, which was tentatively identified
in Wastewater 5, was the only one of
the substances present above the 10
parts per billion level. Its concentration
was estimated at 32 ppb.
Recovery of the substances dosed
into the five wastewaters at the 1 to 20
ppb level was satisfactory to very good
with respect to accuracy and precision
for Wastewaters 1, 3 and 4. Gas
chromatographic analysis to determine
the recoveries from the Wastewaters 2
and 5 could not be performed in some
instances because of interferences that
were not sufficiently removed by clean-
up columns, agitation with mercury,
alkaline hydrolysis and/or extraction
with sulfuric acid. It is very probable that
Wastewater 2 would have been analyzed
with greater success with the Hall
detector than with the electron capture
detector. Since Wastewater 5 was from
a pesticide plant, the limited analytical
success with this wastewater is indica-
tive of the limitations imposed on the
method by high concentrations of
chlorinated substances that are not
among the 25 substances of interest in
this program but that have extraction
and chromatography characteristics
similar to them. Therefore, neither the
Hall detector nor the electron capture
detector is completely satisfactory m
this situation. Better gas chromatog-
raphy resolution or separation of such
interferences before gas chromatog-
raphy is required.
John D. Millar and Richard E. Thomas are with Southwest Research Institute,
San Antonio. TX 78229.
James E. Longbottom is the EPA Project Officer (see below).
The complete report, entitled "Determination of Pesticides and PCBs in
Industrial and Municipal Wastewaters," (Order No. PB 82-214 222; Cost:
$9.00, subject to change) will be available only from:
National Technical Information Service
5285 Port Roy ill Road
Springfield, VA. 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Environmental Monitoring and Support Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
*USGPO: 1982 — 559-092/3424
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