RESIDUE REVIEWS VOLUME 23 RESIDUE REVIEWS Residues of Pesticides and Other Foreign Chemicals in Foods and Feeds RUCKSTA NDS. . BERICHTE Riickstande von Pesdciden und anderen Fremdstoffen in Nahrungs- und Futtermitteln Edited by FRANCIS A. GUNTHER Riverside, California ADVISORY BOARD F. BAR, Berlin, Germany • F. BRD-RAsMUSSEN, Copenhagen, Denmark J. W. COOK, Washington, D.C. • D. G. CROSBY, Davis, California S. DORMAL-VAN DEN BRUEL, Bruxelles, Belgium C. 1. DUNN, Wilmington, Delaware • H. FREHSE, Leverkusen-Bayerwerk, Germany J. C. GAGE, Macclesfield, England· H. GEISSBUHLER, 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 PIETRI·ToNELLI, Milano, Italy • R. TRUHAUT, Paris, France VOLUME 23 SPRINGER-VERLAG BERLIN • HEIDELBERG • NEW YORK 1968 ISBN-13: 978-1-4615-8439-1 e-ISBN-13: 978-1-4615-8437-7 DOl: 10.1007/978-1-4615-8437-7 All rights, especially that of translation into foreign languages, reserved. It is also forbidden to reproduce this book, either whole or in part, by photomechanical means (photostat, microfilm and/or microcard) or by other procedure without written permission from the Publishers. © 1968 by Springer-Verlag New York Inc. Softcover reprint of the hardcover 1st edition 1968 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. Title No. 6625 Preface That residues of pesticide and other "foreign" chemicals in foodstuffs are of concern to everyone everywhere is amply attested by the reception accorded previous volumes of "Residue Reviews" and by the gratifying en- thusiasm, sincerity, and efforts shown by all the individuals 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 displaced by newly developed ones more acceptable to food technologists, pharma- cologists, toxicologists, and changing pest-control requirements in progressive food-producing economies. These matters are also 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 persisting into our food- stuffs are not simple matters, and they incorporate the considered judgments of many individuals highly trained in a variety of complex biological, chemi- cal, food technological, medical, pharmacological, and toxicological dis- ciplines. It is hoped that "Residue Reviews" will continue to serve as an integrat- ing 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 en- deavors; 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 in- terests in it are so varied that the editor and the Advisory Board earnestly solicit suggestions of topics and authors to help make this international book-series even more useful and informative. "Residue Reviews" attempts to provide concise, critical reviews of timely advances, philosophy, and significant areas of accomplished or needed en- deavor 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 method- ology, biochemistry, human and animal medicine, legislation, pharmacology, physiology, regulation, and toxicology; certain affairs in the realm of food technology concerned 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-control chemicals 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, odo!', ap- pearance, etc., as well as those inadvertently added during manufacture, packaging, distribution, 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 editor is necessary before volunteered reviews are submitted in manuscript form. Department of Entomology F.A.G University of California Riverside, California May 3, 1968 Table of Contents Use and residues of mercury compounds in agriculture By N. A. SMART . 1 Pesticide residues in Canada By A. B. SWACKHAMER 37 Ueber den Abbau von Dazomet im Boden By N. DRESCHER and S. Orro . 49 Examinations of Danish milk and butter for contaminating organo- chlorine insecticides By F. BRO-RASMUSSEN, Sv. DALGAARD-MIKKELSEN, Th. JAKOB- SEN, Sv. O. KOCH, F. RODIN, E. UHL, and K. VOLDUM-CLAUSEN. 55 The fundamental kinetics of cholinesterase reaction with substrates and inhibitors in an automated, continuous flow system By G. Voss. 71 The dipyridylium herbicides, paraquat and diquat By A. A. AKHAVEIN and D. 1. LINSCOTT 97 Subject Index . 147 Manuscripts in Press 152 Use and residues of mercury compounds in agriculture By N. A. SMART* Contents I. Introduction . 2 II. Mercury compounds used 3 III. Diseases controlled and rate of use of mercury compounds 4 IV. Formulation and extent of use 9 (a) Formulation 9 (b) Extent of use 9 V. Methods of residue analysis 10 (a ) Wet oxidation-thiocarbazone methods 10 (b) Schoniger flask combustion methods 14 (c) Neutron·activation analysis 15 (d) General 15 VI. Residues in edible crops and tissues 15 (a) Apples . 16 (b) Pears 19 (c) Tomatoes 19 ( d) Potatoes 20 (e) Grain 21 (f) Animal material, including eggs 22 (g) Water . 25 (h) Soil. 26 (i) Other crops and materials 26 VII. Movement of mercury in plants and trees 27 VIII. Regulatory 29 Summary 30 Resume. 31 Zusammenfassung 32 References . 32 .. Ministry of Agriculture, Fisheries & Food, Plant Pathology Laboratory, Hatching Green, Harpenden, Hertfordshire, England. 2 N. A. SMART I. Introduction Mercury compounds were first used in Germany as seed dressings to con- trol seed-borne diseases of cereals about 1914. 'Uspulun', described as a 'chlorophenolmercury' compound was placed on the market in 1915 by Bayer A.G. as a liquid dressing and was soon widely used. Dusts, such as 'Ceresan', at first having phenylmercury acetate as the active ingredient and, subsequently, a methoxyethylmercury compound, and 'Agrosan', a tolylmercury acetate formulation, became more widely used ten years later. Liquid treat- ments, using alkylmercury active ingredients, were reintroduced about the time of World War II because of the reduced hazards and inconvenience to operators dressing the grain in specially designed machines, although alkyl- mercury compounds are more toxic than arylmercurials. In Sweden it has recently been found that the extensive use of alkylmercury compounds can lead to harmful contamination of the environment and there they have been replaced by other organomercury compounds. In most countries both liquid and dust treatments are commonly used. Formulations containing organo- mercurials have been found to give a better control of fungal diseases of grain than non-mercurial formulations. Mercury compounds are now also used as foliar sprays, as aerosols in glasshouses, in the wood pulp and paper industries, and in a variety of other ways. The monetary value of mercury compounds used in world agriculture is at least five million pounds sterling per annum. The possible hazardous nature of mercury residues in foodstuffs was emphasized in the 1950's at Minamata, Kyushu, Japan. An efHuent system from a chemical factory had been opened for passing waste containing, among other products, amounts of mercury into Minamata Bay. The bay was regularly used as a source of seafood for many of the families inhabit- ing the eleven small villages along its shores. In 1953 severe neurological disorders among people living in the area were recorded, most ending fatally or with severe disability. All the persons affected had eaten fish or shell- fish, which contained high levels of mercury, caught on the bay. Cats and fish-eating birds were also affected. A methylmercury compound in the fish was considered to be the main toxic agent. In January, 1966, the Swedish Royal Commission on Natural Resources held an international symposium in Stockholm on a number of facets of the mercury residue problem; the extent to which grain is dressed, mercury levels in the Swedish aquatic environment, modern methods of determining mercury residues such as neutron-activation analysis, the chemical nature of mercury residues, and other related topics were covered. Attention was drawn to the importance of distinguishing between alkyl, aryl, and inor- ganic mercury in order to evaluate the potential hazards of mercury residues Residues of mercury compounds 3 and chromatographic procedures for achieving these separations were pre- sented. Although proceedings of this interesting symposium have not yet been published, some of the work presented there is discussed in this pres- ent review. Information on the diseases controlled, mode of application and residues of mercury compounds in crops and foodstuffs, and methodology of residue analysis are widely dispersed in numerous publications; this review brings together essential data for those concerned with crop protection and its problems. II. Mercury compounds used Organomercury compounds are widely used in world agricultute con- trasted with lesser amounts of inorganic mercury compounds. The former may be divided, chemically, into three groups: alkylmercury, alkyloxyalkyl- mercury, and arylmercury compounds. Many of the organomercury com- pounds may be regarded as salts of the moderately strong bases methyl- mercury, ethylmercury, and alkyloxyalkylmercury hydroxides, or the weaker base phenylmercury hydroxide, with acids such as hydrochloric, hydrobromic, hydriodic, nitric, acetic, propionic, lactic, salicylic, benzoic, and silicic. Com- pounds known to be used in world agricultute at the present time are: Alkylmel'cul'Y compounds Methylmercury sulphate, acetate, nitrile, propionate, 8-hydroxyquinolate, 2,3-dihydroxypropyl mercaptlide, pentachlorophenolate, p-chlorobenzoate, benzoate, dicyandiamide N -Methylmercury I,2,3,6-tetrahydro-3,6-endomethano-3,4,5,6, 7, 7 -hexachloro- phthalimide Ethylmercury silicate, chloride, bromide, phosphate, acetone, urea, oleate, stearate, pentachlorophenolate, hydroxide, thiouronium chloride, p- toluene sulphonamide, 8-hydroxyquinolate N -Ethylmercury 1,2,3 ,6-tetrahydro-3 ,6-endomethano-3 ,4,5 ,6, 7,7 -hexachloroph- thalimide Ethyl phenethynylmercury Mercury pentanedione Alkyloxyalkylmel'cury compounds Methoxyethylmercury ohloriide, silicate, dicyandiamide, benzoate, lactate, acetate Ethoxyethylmercury ohloride, silicate, hydroxide I-Carboxy-3-ethoxyethylmercury propandicarboxylate Chloromethoxypropy lmercury acetate p- (t-Oetyl) phenoxyethoxyethyl dimethylmercury benzyl ammonium chloride Al'ylmel'cury compounds Phenylmercury acetate, dimethyl dithiocal1bamate, chloride, dinaphthyl methane sulphonate, urea, nitrate, iodide, benzoate, pyrocatechinate, triethanol ammonium lactate, 8-hydroxyqUlinolate, hydroxide, lactate, oleate, pro- pionate, salicylate, salicylanilide, formamide, naphthenate 4 N. A. SMART N -Tolylmercury-p-toluene sulphanilide, tolylmercury chloride Hydroxymercurichlorophenol, ihydroxymerourinitrophenol Cresolmercury naphthenate Diphenylmercury dodecenyl succinate o-(Hydroxymercury) benzoic acid Inorganic mercury compounds Mercurous chloride Mercutlic chloride Mercuric oxide III. Diseases controlled and rate of use of mercury compounds Many fungus diseases of seeds, bulbs, plants, fruits, and vegetation are controlled by mercury compounds, as shown in Table 1. Mercury compounds are used for control of soil-borne fungi as well as of seed-borne diseases in the United States whereas in most European countries they are predomi- nantly used to control the latter. Phenylmercury acetate is widely used in the wood-pulp and paper-making industry: about 90 percent of ground wood pulp exported from Norway, Sweden, Canada, and the United States contains up to 20 p.p.m. of mer- curial and the compound is also widely used in slime control. A minor use of organomercury compounds in forestry is in helping to preserve cut timber. Table I also gives the range of rate of use of mercurials in world agri- culture as far as can be ascertained. The ranges are large in some cases re- flecting the different practices of countries.