«: AGROCHEMICALS: FATE IN FOOD AND THE ENVIRONMENT PROCEEDINGS OF A SYMPOSIUM, ROME, 7 - 1 1 JUNE 1982 JOINTLY ORGANIZED BY IAEA AND FAO l^J I N T E R ...»
Studies on weathering, degradation, absorption, translocation and accumulation of l^c-lindane in coffee plants have shown that, 10 days after topical application to the leaf s u r f a c e, the insecticide can be shown to have been absorbed and translocated to d i f f e r e n t parts of the plant. I t accumulates mainly in the roots and appears in other leaves . In these experiments, when plants are grown in nutrient solution, release of radiocarbon through roots could be detected, indicating exchange of labelled material between plant and surrounding media. When the insecticide is applied to coffee plants through the roots immersed in nutrient solution containing 1 4 C-lindane, the labelled material is absorbed, and after 24 hours, radioactive material can be detected in young leaves of the upper parts of the plant. Loss of l^C-lindane by v o l a t o l i s a t i o n, evaporation and c o d i s t i l l a t i o n with water is apparently continuous and represents a s i g n i f i c a n t portion of that applied.
It is not d i f f i c u l t to imagine how many problems would have to be overcome in order to carry out such studies without the aid of isotopes.
Most of us associated with the study, evaluation and regulation of residues in food have long held the desire to know what happens to these residues in processing and cooking.
Mirna et a l. Report a study of the type which provides a clear and adequate picture of the influence of processing on the residue content of meat and meat Meat from r a b b i t s, which had been fed with 1 4 C-lindane was products.
processed to produce dried sausage and various meat products. It was found that micrococci and l a c t o b a c i l l i from a commercial starter culture metabolised the labelled pesticide to a considerable extent depending upon the temperature and time of incubation. In dried sausage the lindane content decreased in the course of 30 days by an average of about 25%. Curing caused a reduction of about 20% and hot-smoking a reduction of 12% in the lindane content of the meat products. Cooking ( 1. 5 hours at 100°C) was the most e f f e c t i v e treatment, more than 50% of the pesticide content being removed. In a l l of the meat products the residues consisted mainly of lindane together with small amounts of chlorinated benzenes and phenols .
Oxamyl is a new formamidine type of insecticide with pronounced cholinesterase a c t i v i t y which appears to have wide application as a contact insecticide with moderate residual activity against a wide spectrum of insect pests. It has systemic action in many plants and, when applied to the s o i l, functions as a contact type broad-spectrum nematocide and, bysystemic action, as a miticide/insecticide.
IAEA-SM-263/30 It is interesting to note the extent to which nuclear techniques have featured in the research and development work which led to the clearance and registration of this insecticide in recent years.
Among the studies that were available two years ago was a most extensive study of the metabolism of oxamyl and selected metabolites in the rat  and an in vitro study o f rat liver microsomal metabolism of oxamyl and selected metabolites [ 5 0 ].
The study of metabolism of oxamyl in plants  involved a comprehensive examination of the fate of oxamyl in tobacco, a l f a l f a, peanuts, potatoes, oranges and tomatoes . These involve not only the i d e n t i f i c a t i o n of the metabolites but also their d i s t r i b u t i o n throughout the plant, plant parts and various components of the f r u i t. Treatment involves both foliar and soil application and steps were taken to observe the e f f e c t of time of a p p l i c a t i o n, number of applications and rate of application on the nature and level of the residues.
A ruminant metabolism study involving two lactating goats maintained on diets containing 14c-oxamyl for 10 and 20 days provided information on the degradation, elimination and accumulation in numerous organs, m i l k, blood and tissues [ 5 2 ]. This was followed by a more recent study in which l 4 C-labelled oxamyl and selected metabolites were incubated, in v i t r o, in rumen fluid of a Holstein cow .
A livestock-feeding study in which radiolabelled oxamyl was fed to dairy cows in their rations for 30 days  clearly showed that no residues were detectable in any samples of milk or milk f r a c t i o n s, l i v e r, kidney, lean muscle or subcutaneous fat at any feeding l e v e l. These same samples were later analysed for major metabolites which were also found to be absent [ 5 5 ].
In a poultry-feeding study, adult laying hens were fed diets containing varying airounts of radiolabelled oxamyl for a four-week period [ 5 6 ]. Samples of eggs and tissues were collected and analysed for oxamyl and major metabolites. Residues of oxamyl and major metabolites were found to be at levels below the limit of determination in e g g s, l i v e r, muscle, fat and s k i n.
Numerous studies have been conducted on oxamyl soil metabolism, decomposition, d i s s i p a t i o n, absorption, mobility and the e f f e c t of water on dissipation and decomposition. In one compilation of studies the decomposition of oxamyl in s o i l and water was investigated with various s o i l s under aerobic and anaerobic conditions and in d i s t i l l e d water or river water at various levels of pH, with a r t i f i c i a l UV l i g h t or s u n l i g h t, and in the dark. Also included were experiments on soil leaching and mobility in various soils [ 5 7 ].
In a crop rotation study, cabbage, red beets and sorghem seeds were grown in the green house in soils treated 30 and 120 days earlier with 14c-oxamyl . These studies showed that mature crops from s o i l s treated 30 days prior to planting contained low levels of residues but those planted in soils treated with oxamyl 120 days e a r l i e r contained no measurable residues of oxamyl or main metabolites.
 ANDRAWES, N. R., and BAGLEY, W. P., Degradation of 2-methyl-2-(methylthio) propionaldehyde-O-(methylcarbamoyl) oxime (Temik) in potato f o l i a g e, UCC Project Report 10495 (Nov. 11 1968) (unpublished).
 ANDRAWES, N. R., The metabolism and terminal résidues of Temik a l d i c a r b pesticide in peanut plants under f i e l d conditions, UCC Project Report 17613 (Sept. 14 1972) (unpublished).
110] ANDRAWES, N. R., BAGLEY, W. P., HERRETT, R. A., Metabolism of Temik aldicarb p e s t i c i d e, (2-methyl-2-(methylthio)-propionaldehyde O-(methylcarbamoyl) oxime in sugar beets, UCC Project Report 12694 (May 1, 1970) (unpublished).
 ANDRAWES, N. R., BAGLEY, W. P., Degradation and carry-over properties of 2-methyl-2-(methlythio) propionaldehyde 0-(methyl-carbamoyl) oxime (Temik) i s s o i l, UCC Report 10494 (Nov. 1 9, 1968) (unpublished).
 KAMESKAI, S., INOUE, Y., KONISHI, K., KONO, Y., OSHIKO, Y., SAKAI, M.
Fate of cartap in plants ( I V ), Isolation of metabolites in rice plants, Takeda Chemical I n d u s t r i e s, Ltd. (1976) (unpublished report).
 SUGITA, N., TAKABATAKE, A., TAN, N. Fate of cartap in plants (V).
Primary metabolites in rice plants, Takeda Chemical I n d u s t r i e s, Ltd.
(1978) (unpublished report).
"Metabolism of l 4 c-Labelled Organochlorine  KORTE, F., Insecticides", Nuclear Techniques for Studying Pesticide Residue Problems (Proc. Panel Vienna, 1968) IAEA, Vienna (1970) 23-37.
 WALKER, С. Н., EL-ZORGANI, G. A., KENNY, J., "Radiotracer-Aided Studies on the Comparative Metabolism of Dieldrin Analogues by V e r t e b r a t e s ", Isotope Tracer Studies of Chemical Residues in Food and the Agricultural Environment (Proc. Panel I s p r a, 1972) IAEA, Vienna (1974) 65-68.
MÜLLER, G. NOHYNEK, A. PARLAR, D. PRESTEL, К. SANDROCK, N. SOTIRIOU, P.
VISWANATHAN, S. VISWANATHAN, D. VOCKEL, I. WEISGERBER. "Comparative Behaviour of Organochlorine Insecticide and Related Chemical Residues in Model Ecosystems", O r i g i n and Fate of Chemical Residues in Food, Agriculture and Fisheries (Proc. and Report, Research Meetings) IAEA, Vienna, (1975) 35-60.
 SHELL INTERNATIONAL, Photochemical degradation of SD 14114- H 9 S n on a glass surface, Report TIR-22-113-73 (1973) (unpublished).
 HEYKANTS, J., MEULDERMANS, W., HURKMANS, R. On the excretion, metabolism and tissue distribution of imazalil-Зн in the male and female Wistar r a t, Janssen Pharmaceutica, Department of Drug Metabolism, Report 5712 (1978).
 Anonymous, Metabolism of imazalil in barley plants, (Addition to the First Report of Project 2, 7 6 0 5 2 1 ), Biochemical Department of the Institute for Organic Chemistry, Utrecht ( 1 9 7 6 ).
 MEULDERMANS, W. et a l., The metabolic fate of imazalil on banana plants, Janssen Research Products I n t. Service Report, R23979/21 (undated).
 Anonymous, Metabolism of imazalil applied to oranges, Report of Project l.II; 760224, Biochemical Department of the Institute for Organic Chemistry TNO, Utrecht ( 1 9 7 6 ).
 Anonymous, Degradation of imazalil in oranges, Progress report of project 1. 1 : 751106, Biochemical Department of the Institute for Organic Chemistry TNO, Utrecht - The Netherlands. (1975).
 KRAGHT, A. J., Metabolism of imazalil applied to oranges: metabolite study by tracer technique, Pennwalt Corporation, Decco D i v i s i o n, USA Report 770518 ( 1 9 7 7 ).
 Anonymous, A study of the fate of imazalil in s o i l ; Report of Project 4 761021, Biochemical Department of the Institute for Organic Chemistry TNO, Utrecht ( 1 9 7 6 ).
 FIORES-RUEGG, E., MESQUITA, Т. В., "Persistence and Distribution of
-lindane residues in coffee p l a n t s ". Trace Contaminants of Agriculture, Fisheries and Food in Developing Countries, Report and Conclusions of Series of Co-ordinated Studies IAEA, Vienna (1976) 3-8.
 MIRNA, A., HECHT, H., CORETTI, A., "Influence of Processing on the Gamma-hexachlorocyclohexane Content of Meat Products", Origin and Fate of Chemical Residues in Food, Agriculture and Fisheries - (Proc. Rep.
Research Co-Ordination Meetings) IAEA, Vienna (1975) 115-120.
 HAN, J.C-Y. Di vitro rat liver microsomal metabolism of oxamyl and selected metabolites of oxamyl (Unpublished report) Biochemicals Dept., Du Pont de Nemours and Company, Wilmington, USA (undated).
 HARVEY, J. J R. Metabolism of 14c-oxamyl in the lactating goat (Unpublished undated s t u d y ), Biochemicals Department of Du Pont de Nemours and Company, Wilmington, USA.
 DU PONT. Livestock feeding study. (Unpublished study dated 4-19-76) Biochemicals D e p t., Du Pont de Nemours and Company, Wilmington, USA (1976).
 ZAHNOW, E. W. Oxamyl - Chicken and egg feeding study. (Unpublished study dated 12-4-78). Biochemicals Dept., Du Pont de Nemours Company (1978).
 HUNT, L. M. and GILBERT, B. N. Distribution and excretion rates of l^C-labelled permethrin isomers administered orally to four lactating goats for 10 d a y s, J. A g r i e. Food Chem. 25 3 (1977) 673.
 BEWICK, D. W. and LEAHEY, J.'P. Permethrin : Absorption in cows, ICI Plant Protection Division Report No. TMJ1357B (unpublished) (1976).
 LEAHEY, J. P., BEWICK, D. W., GATEHOUSE, D.M. and CARPENTER, P. K.
Permethrin : Absorption in chickens after dermal and oral treatments, I C I Plant Protection Division Report No. TMJ1481B (unpublished) ( 1 9 7 7 ).
RATIONALE IN THE DESIGN OF PESTICIDE METABOLISM STUDIES USINGRADIOISOTOPES.
Numerous physical, chemical and biochemical forces act on pesticides in the environment to regulate their persistence and, to a large extent, determine their environmental and toxicological significance. Radioisotope-aided metabolism studies with pesticides in both target and non-target organisms are important to define the qualitative and quantitative aspects of pesticide degradation involved. Such studies provide valuable information that can be used in a number of ways, including prediction of the nature of potential pesticide interactions with man, estimation of potential residue occurrence in human foods, determination of pesticidal mode of action, and evaluation of potential toxicological effects on non-target species. In designing pesticide metabolism studies that utilize radioisotopes as tracers, the metabolism scientist must exercise careful judgement to ensure that his studies generate data that are scientifically sound and relevant to environmental and human health concerns.
Such factors as isotope selection, label position, specific activity, treatment routes, dosage levels, replication, and the utilization of appropriate radiometric and analytical techniques are important considerations to assure the generation of useful data. Because of the very large number of potential pesticide/organism interactions that may be of interest to the metabolism scientist, specific research approaches vary greatly depending on the nature of the study organism and the specific pesticide involved. The rationale often used by metabolism studies in laboratory animals, livestock and poultry, plants, soil and aquatic organisms, arthropods and other pest species, non-target organisms, and for in vitro studies, is considered.
The judicious use of pesticidal chemicals contributes in a very positive way to many aspects of human welfare. During the past few decades, pesticides have no doubt spared millions of human lives through their use to control vectors of often fatal