Table Of ContentRESIDUE REVIEWS
VOLUME 34
RESIDUE REVIEWS
Residues of Pesticides and Other
Foreign Chemicals in Foods and Feeds
RUCKSTANDS-BERICHTE
Riickshinde von Pestiziden und anderen
FremdstofIen in N ahrungs- und Futtermitteln
Editor
FRANCIS A. GUNTHER
Assistant Editor
JANE DAVIES GUNTHER
Riverside, California
ADVISORY BOARD
F. BAR, Berlin, Germany· F. BRO-RASMUSSEN, Copenhagen, Denmark
J. W. COOK, Washington, D.C. • D. G. CROSBY, Davis, California
S. DORMAL-VAN DEN BRUEL, BruxeIles, Belgium
C. L. DUNN, Wilmington, Delaware • H. FREHSE, Leverkusen-Bayerwerk, Germany
J. C. GAGE, Macclesfield, England • H. GEISSBiliILER, Basel, Switzerland
S. A. HALL, Beltsville, Maryland· T. H. HARRIS, Bethesda, Maryland
L. W. HAZLETON, Falls Church, Virginia· H. HURTIG, Ottawa, Canada
O. R. KLIMMER, Bonn, Germany • G. K. KOHN, Richmond, California
H. F. LINSKENS, Nijmegen, The Netherlands· H. MAIER-BoDE, Bonn, Germany
N. N. MELNIKOV, Moscow, U.S.S.R .• R. MESTRES, Montpellier, France
P. DE PmTRI-TONELLI, Milano, Italy· R. TRUHAUT, Paris, France
VOLUME 34
SPRINGER-VERLAG
BERLIN • HEIDELBERG • NEW YORK
1971
ISBN-13: 978-1-4615-8472-8 e-ISBN-13: 978-1-4615-8470-4
DOl: 10.1007/978-1-4615-8470-4
All rights reserved. No part of this book may be translated or reproduced in
any form without written permission rrom Springer-Verlag.
© 1971 by Springer-Verlag New York Inc.
Library of Congress Catalog Card Number 62-18595.
The use of general descriptive names, trade names, trade marks, etc. in this
publication, even if the former are not especially identified, is not to be taken
as a sign that such names, as understood by the Trade Marks and Merchandise
Marks Act, may accordingly be used freely by anyone.
Preface
That residues of pesticide and other "foreign" chemicals in food
stuffs are of concern to everyone everywhere is amply attested by the
reception accorded previous volumes of "Residue Reviews" and by
the gratifying enthusiasm, sincerity, and efforts shown by all the in
dividuals from whom manuscripts have been solicited. Despite much
propaganda to the contrary, there can never be any serious question
that pest-control chemicals and food-additive chemicals are essential
to adequate food production, manufacture, marketing, and storage, yet
without continuing surveillance and intelligent control some of those
that persist in our foodstuffs could at times conceivably endanger the
public health. Ensuring safety-in-use of these many chemicals is a
dynamic challenge, for established ones are continually being dis
placed by newly developed ones more acceptable to food tech
nolOgists, pharmacolOgists, tOxicologists, and changing pest-control
requirements in progressive food-producing economies.
These matters are of genuine concern to increasing numbers of
governmental agencies and legislative bodies around the world, for
some of these chemicals have resulted in a few mishaps from improper
use. Adequate safety-in-use evaluations of any of these chemicals per
sisting into our foodstuffs are not simple matters, and they incorporate
the considered judgments of many individuals highly trained in a
variety of complex biological, chemical, food technological, medical,
pharmacolOgical, and tOXicological disciplines.
It is hoped that "Residue Reviews" will continue to serve as an
integrating factor both in focusing attention upon those many residue
matters requiring further attention and in collating for variously trained
readers present knowledge in specific important areas of residue and
related endeavors; no other single publication attempts to serve these
broad purposes. The contents of this and previous volumes of "Residue
Reviews" illustrate these objectives. Since manuscripts are published
in the order in which they are received in final form, it may seem that
some important aspects of residue analytical chemistry, biochemistry,
human and animal medicine, legislation, pharmacology, physiology,
regulation, and toxicology are being neglected; to the contrary, these
apparent omissions are recognized, and some pertinent manuscripts
are in preparation. However, the field is so large and the interests in it
are so varied that the editors and the AdvisOry Board earnestly solicit
suggestions of topics and authors to help make this international book
series even more useful and informative.
v
vi Preface
"Residue Reviews" attempts to provide concise, critical reviews of
timely advances, philosophy, and significant areas of accomplished or
needed endeavor in the total field of residues of these chemicals in
foods, in feeds, and in transformed food products. These reviews are
either general or specific, but properly they may lie in the domains of
analytical chemistry and its methodology, biochemistry, human and
animal medicine, legislation, pharmacology, physiology, regulation,
and toxicology; certain affairs in the realm of food technology con
cerned specifically with pesticide and other food-additive problems
are also appropriate subject matter. The justification for the prepara
tion of any review for this book-series is that it deals with some aspect
of the many real problems arising from the presence of residues of
"foreign" chemicals in foodstuffs. Thus, manuscripts may encompass
those matters, in any country, which 'are involved in allOwing pesticide
and other plant-protecting chemicals to be used safely in producing,
storing, and shipping crops. Added plant or animal pest-conh'ol chem
icals or their metabolites that may persist into meat and other edible
animal products (milk and milk products, eggs, etc.) 'are also residues
and are within this scope. The so-called food additives (substances
deliberately added to foods for flavor, odor, appearance, etc., as well
as those inadvertently added during manufacture, packaging, distribu
tion, storage, etc.) are also considered suitable review material.
Manuscripts are normally contributed by invitation, and may be in
English, French, or German. Preliminary communication with the
editors is necessary before volunteered reviews are submitted in manu
script form.
Department of Entomology F.A.G.
UniverSity of California
Riverside, California
December 10, 1970
Table of Contents
Determination of organophosphorus pesticide residues in fruits
and vegetables on the Swedish market from 1964 to 1968
By SIV RENVALL and MALIN AKERsLOM . 1
Pesticide residue analysis in the presence of polychlorobiphenyls
(PCB's)
By L. M. REYNOLDS. 27
Development of the Food and Drug Administration's method of
analysis for multiple residues of organochlorine pesticides in
foods and feeds
By JERRY A. BURKE . 59
The metabolism of contact insecticides in stored grains. II.1966-
1969
By D. G. ROWLANDS . 91
The role of pesticides in pollution management
By KENNETII C. WALKER 163
Subject Index 173
vii
Determination of organophosphorus pesticide residues in
fruits and vegetables on the Swedish market
from 1964 to 1968
By
SN RENVALLo and MALIN AKERBLOMo
Contents
I. Introduction 1
II. Methods 2
a) Extraction procedure 3
b) Cleanup procedure 3
c) Determination of cholinesterase inhibition 4
d) Gas chromatography (GC) 7
e) Thin-layer chromatography . 10
f) Recovery experiments . 11
TIL Results and discussion 12
a) Collection and origin of samples. 12
b) Results of screening with cholinesterase . 13
c) Results of gas chromatographic analysis 15
d) Crops with high residue content . 15
e) Frequently occurring pesticides . 19
f) Distribution of pesticides between peel and pulp 20
g) Residues found compared with tolerances in Sweden 20
h) Methodological aspects 21
IV. General comments . 21
Summary 23
Resume. 23
Zusammenfassung 24
References . 25
I. Introduction
International food trade has been accelerated by rapid enlargement
of trading areas, improved transportation, and food technology. Large
quantities of fresh fruit and fresh vegetables are imported into Sweden
from all parts of the world. The chemical treatment of produce from
different countries is difficult to survey.
o National Institute of Plant Protection, 171 07 Soma, Sweden.
1
S. RENVALL and M. .AK:Eru3LOM
Considerable attention has recently been focused on the possible
health hazards of pesticide residues in foods, and the Food and Agri
culture Organization (FAO) and World Health Organization (WHO)
have published a series of reports dealing with general principles
of pesticide residue safety in food. For some pesticides tolerances
and temporary tolerances have been recommended (FAG/WHO
1968 a and b, 1969 a and b).
Many investigations have been made on pesticide residues in foods
ready for consumption, including data obtained by total diet studies
(e.g., ABBOTT et al. 1969, COFFIN 1964, DUGGAN and WEATHERWAX
1967, HARRIES et al. 1969, KRAUSE and KIRCHHOFF 1969, THOMPSON and
HILL 1969, WESTOO et al. 1969). Most of these investigations deal with
organochlorine pesticides. For some years the organophosphorus pesti
cides have been used on an increasing scale as insecticides and acari
cides in agriculture and in orchards. They tend to replace the organo
chlorine pesticides, which have been in use for many years. In total
diet studies, tlle presence of organophosphorus pesticides has been
reported less frequently than the presence of organochlorine com
pounds. This is probably partly due to the shorter persistence of
these compounds, and to the lower dosage, necessary for pest control,
but may also be due to analytical problems associated with these
compounds, which undergo numerous chemical alterations after appli
cation to the crop. Some of these intermediate compounds are more
toxic than the parent compounds.
The purpose of the present investigation was to examine residues
of organophosphorus pesticides in domestic and imported fruit and
vegetables of unknown agricultural history marketed in Sweden.
About 2,400 samples were collected and analysed from 1964 to 1968.
II. Methods
Methods for the determination of residues of organophosphorus
pesticides in foods were reviewed in 1967 by ABBOTT and EGAN. The
methods presented in this investigation were made as simple as possi
ble to give a survey of the presence of the most common organophos
phorus pesticides in fruit and vegetables.
A cholinesterase inhibition method has been used as a screening
test to sort out samples without detectable amounts of pesticides
(ARCHER 1963, GAGE 1961). The, Warburg manometric technique was
used (AUGUSTINSSON 1957). In most samples with cholinesterase in
hibition the pesticides were identified and quantitatively determined
by gas-liquid chromatography. In samples with more than 0.1 mg./kg.,
the results were confirmed by thin-layer chromatography. Quantitative
determination of metabolites is not included in the investigation; the
metabolites were observed only as an unidentified cholinesterase in
hibition effect.
Residues on Swedish market 3
The, individual steps of the analytical procedure were:
Extraction of the chopped sample with dichloromethane.
Screening of the dichloromethane ("crude") extract for cholinesterase
inhibition.
Cleanup of the crude extract on an alumina column. Elution with petro
leum ether, fraction I, and thereafter with petroleum ether/acetone,
fraction II.
Determination of the cholinesterase inhibition of fraction II, and in some
cases, of fraction 1.
Gas chromatographic analysis on two different columns with the phos
phorus detector.
Thin-layer chromatography for verification of identity of pesticides
observed.
a) Extraction procedure
From a fresh sample of 0.5 to l.5 kg. of fresh crop a finely chopped
aliquot of 100 g. (50 g. of lettuce or spinach) was taken. It was macerated
in a Turmix blendor with 200 m!. of dichloromethane (purum, redistilled,
b.p. 390 to 410 C.) for two-to-three minutes. The slurry was transferred to
a stoppered flask and was left to the next day at room temperature. The
slurry was filtered and the crude dichloromethane extract was dried by
passage through a 3-cm. column (Ld. l.5 cm.) of anhydrous sodium sul
phate (A.R.). A reference aliquot of 50 or 100 g. of every chopped sample
was deep-frozen.
Many solvents have been reported in the literature for the extrac
tion of organophosphorus pesticide residues from crops. LAWS and
WEBLEY ( 1961 ) recommended dichloromethane for its favourable
extraction characteristics for both organochlorine and organophos
phorus pesticide residues including metabolites. This solvent has been
used in the present investigation. The effectiveness of one extraction
with dichloromethane has been tested against repeated extractions
of samples containing residues with satisfactory results. It was ob
served that on storage of dichloromethane extracts of samples with
residues in brown bottles at room temperature (250 C.), most of
the detected pesticides were very stable. The concentration of ethion
and parathion in these extracts was the same after one year. The
same stability was not found in extracts purified by alumina column
chromatography.
b) Cleanup procedure
A chromatographic tube (l.5 cm. i.d. and 40 em. long) was packed
with ten g. (5.5 cm.) of aluminum oxide (activity grade II-III, BROCK
MANN) and a top layer of two cm. of anhydrous sodium sulphate. The col
umn was washed and pre-wetted with 50 m!. of petroleum ether (purum,
4 S. RENVALL and M. AxEImLOM
redistilled, b.p. 40° to 50° C.). An aliquot of 100 ml. of crude extract was
evaporated just to dryness in a vacuum evaporator at 30° to 40° C. The
residue was transferred to the column with three ml. of petroleum ether.
+
The evaporation flask and the sides of the tube were washed with 3 3
ml. of petroleum ether. The column was eluted with 50 ml. of petroleum
+
ether (fraction I), then with 100 25 ml. of three percent v/v acetone
(purum, redistilled, b.p. 55S to 56.5° C.) in petroleum ether (fraction
II:l and II:2).
With gas chromatographic determination of organophosphorus
pesticides with a specific phosphorus detector, the cleanup of crop
extracts does not need to be very thorough. The absorption of pigments
and waxes on a chromatographic column is, however, advisable. For
thin-layer chromatography a cleanup is necessary.
c) Determination of cholinesterase inhibition
The Warburg manometric technique was used for assaying
cholinesterase activity.
1. Reagents.
Standard solutions of pesticides: A concentration of one /Lg./ml.
(in ethyl acetate or petroleum ether) is convenient. The purities of the
pesticides involved are listed in Table I.
Chlorinesterase solutions: (a) Purified preparation from human
blood selUm, freeze-dried/ 40 mg./lOO ml. of buffer solution. (b) Bovine
cholinesterase (pseudo) B grade, 6.3 units/mg. (Calbiochem, Lucerne,
Switzerland), 7.5-10.0 mg./l00 ml. of buffer solution. The enzyme
solutions are deep-frozen in portions of 7-8 mI., which is the amount
needed for a Warburg set. Enzyme (a) was used from 1964 to 1965 and
(b) from 1966 to 1968.
Bromine water: 0.2 mI. of glass-distilled water saturated with bromine
was diluted to 50 mI. Fresh solution was prepared every two weeks.
Buffer solution: According to AUGUSTINSSON (1957), i.e., 0.15 M NaCl,
0.025 M NaHC0 and 0.04 M MigCl2 '6H,O in glass-distilled water, pH
3,
7.8. Fresh solution was prepared every day.
Substrate: 0.0666 g. of acetylcholine chlorhydrate (Merck, Darmstadt,
Germany) dissolved in five m!. of buffer solution just before use.
2. Apparatus.
Warburg apparatus (B. Braun, Melsingen, Germany) with 14 mano
meters. The flasks have one side bulb and a total capacity of approxi
mately 15 ml. each.
3. Procedure.
One mI. of the crude or purified crop extract was added to the main
compartment of the Warburg flask. The solvent was evaporated by a
stream of air and the residue was treated with dilute bromine water 0.2
mi. for clUde and 0.1 ml. for purified extracts. Exactly 0.5 ml. of e~yme
Kindly donated by AB Kabi, Stockholm, Sweden.
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