«: 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 ...»
Acephate, a relatively new organophosphorous insecticide, is increasingly used in North America for control of forest insects, whereas parathion, an older organophosphorous insecticide, is currently employed in Israel for crop protection with emphasis on cotton. In both instances, since application is usually by aerial spraying, these pesticides often enter adjacent and commercially important water bodies. In western Canada/United States of America these are salmonid spawning rivers, whereas in Israel they are fish (.Tilapia/czip) ponds. Concern has often been expressed about the effects of these pesticide additions on these aquatic ecosystems, which support a fishery. This project was therefore initiated to investigate the effects of acephate and parathion on one biotic component of aquatic food webs, the bacteria of the plankton and benthos. Limnocorrals of 2 m in diameter by 5 m in height were placed in Shirley Lake, a Canadian west coast temperate/dystrophic lake (49° 21' N, 122° 33' W), whereas limnocorrals of 1.2 m in width by 1.2 m in length by 1 m in height were placed in a fish pond located at the Fish and Aquaculture Research Station, Dor, Israel ( 3 2 ° 3 7 ' N, 3 4 ° 4 ' E).
The former limnocorrals were treated with 1, 10 or 25 ppm acephate, whereas the latter were treated with 30 — 40 ppb parathion. Both acephate and parathion additions at these concentrations had little effect on the bacterial activities as determined by the glucose heterotrophic potential technique. In addition, parathion treatment at 30 — 40 ppb had little apparent effect on the bacterial numbers and productivities within the fish pond limnocorrals. Acephate, * L.J. Albright and G.H. Geen were associated with the acephate portion and L.J. Albright, A. Gasith, Y. Mozel and A.S. Perry with the parathion portion of the experiments described. The abstract only is published here, since it is intended that the full paper will appear in the IAEA-TECDOC Series (unpriced publication).
however, when added at concentrations of 1, 10 or 25 ppm, stimulated benthic and planktonic bacterial productivities. It was therefore concluded that there is no appreciable adverse influence of these two insecticides on the heterotrophic bacterial component of freshwater food webs at concentrations likely to be encountered in water bodies within and adjacent to these sprayed areas.
Poster Presentation IAEA-SM-263/53
A TEST F O R E N V I R O N M E N T A L CHEMICALS
AFFECTING PHOTOSYNTHESISD.E.W. ERNST Institut für Biophysik, Isotopenlaboratorium der Fakultàt für Gartenbau und Landeskultur, Universitât Hannover and Gesellschaft für Strahlen- und Umweltforschung mbH München, Hannover, Federal Republic of Germany A chlorophyll fluorescence test has been designed to measure the effect o f environmental chemicals in aqueous solution. It was checked by comparison with radiotracer experiments.
Fluorescence o f chlorophyll occurs from the lowest singlet to the ground state. It may be quenched by triplet transitions and radiationless transitions.
Of the latter, natural quenching by the photosynthetic process is the most important. Its intensity depends on the photosynthetic turnover o f the plants, but it is additionally influenced by factors such as previous illumination, temperature and nutrient supply, or metabolic inhibitors such as D C M U, or environmental chemicals.
The basic concept of this method is to add the substance under investigation to a healthy alga culture and to observe the increase in fluorescence. The fluorescence of any plant after a certain dark interval (some minutes) is not constant, but follows the curve described by Kautsky, which displays a maximum peak some seconds after the start o f excitation and then tapers out to an asymptotic value. With increasing damage by the herbicide the difference between the maximum and the asymptotic value decreases.
These effects have been used to test a series o f chemicals, mainly pesticides (Fig. 1). They occurred within 5 min o f addition o f the substance, whereas heavy metals (mercury, cadmium and lead) needed 24 h to show an effect. Synergisms between cadmium, lead and monuron could not be detected.
This fluorescence test has the advantage of being very quick and owing to the portability of the instrument it can easily be carried out in the field.
The fluorometer designed for these measurements incorporates the following
(1 ) Fixed wavelengths. Since the fluorometer is only for chlorophylla measurements, the excitation and emission wavelengths are fixed; hence, filters were used instead o f costly monochromators.
(2) Sedimentation o f algae out o f the light path during measurement. A vertical light path avoids this error.
(3) Weight. The apparatus is designed as a light weight field instrument; a flash lamp minimizes battery weight and a photodiode avoids the expense o f a multiplier.
(4) High efficiency and low background noise require a special design.
Excitation light from the lamp is successively filtered three times; light that is not absorbed in the cuvette is reflected back to the sample.
GEORGI, В., SCHULZE, E„ ERNST, D., "Fluorometric chlorophyll estimation of various algae populations", Shallow Lakes (DOKULIL, M., METZ, H., JEWSON, D., Eds), W. Junk Publishers, The Hague (1980).
KAUTSKY, H., FRANK, U., Chlorophyllfluoreszenz und Kohlensaureassimilation, Biochem.
Z. 315 (1943) 139.
SAMUELSON, G., ÔQUIST, G., HALLDAL, P.R., The variable chlorophyll (a) fluorescence as a measure of photosynthetic capacity in algae, Mitt. Ver. Limnol. 21 (1978) 209.
EFFECTS OF PARATHION ON THE ECOLOGY OF A EUTROPHIC AQUATIC ECOSYSTEM:
Repetitive exposure of a eutrophic fish pond ecosystem, enclosed in limnocorrals to 30 ppb parathion, resulted in elimination of the potentially dominant zooplankton species, Moina micrura. Consequently, populations of the rotifers Brachionus and Asplanchna increased markedly. Changes in the zooplankton composition and abundance were followed by increased fluctuations in phytoplankton biomass, phytoplankton photosynthesis, plankton respiration and community metabolism. Similar responses to parathion treatment were observed in previous studies under fish pond conditions. In the presence of fish the effect of parathion on the ecosystem was generally less pronounced and not uniform. Collapse of the zooplankton community and rapid changes in limnological conditions in the control (untreated) limnocorrals severely limited the duration of the experiment. The results suggest that under eutrophic conditions small enclosures may be useful for evaluation of the effect of toxicants on the ecosystem only in short-term experiments with short-lived chemicals.
* This work was supported by the IAEA under Research Contract No. 1724/R4/SD.
The abstract only is published, since it is intended that the full paper will appear in the IAEA-TECDOC Series (unpriced publication).
PESTICIDES IN SOIL(Session IV) Chairman
BOUND PESTICIDE RESIDUES IN SOIL, PLANTS AND FOOD WITH PARTICULAR
EMPHASIS ON THE APPLICATION OF NUCLEAR TECHNIQUES.
Although so-called bound residues have been detected for all classes of chemicals investigated so far, their quantitative levels have wide-ranging differences, depending on the chemical structure of the pesticide; phenols and nitrogen-containing pesticides exhibit the highest binding rates.
The portion of bound residues in soil and plants increases with time and varies with environmental conditions (soil and plant type, climatic conditions, etc.). So far the chemical identity of bound residues has only been elucidated for a limited number of model substances by using various liberation techniques. Most information is available on anilines; models have been developed demonstrating their copolymerization into natural macromolecules (humic acids, lignin).
Misinterpretation of natural products assimilated from totally degraded pesticides, as bound xenobiotic residues can only be excluded by the sophisticated separation and identification procedures of all residues. Studies on the persistence of bound residues showed differing mineralization rates, depending on the chemical structures of the pesticides; research on the bioavailability revealed that for all pesticides low amounts of soil-bound residues are taken up by plants, and that plant-bound residues are eliminated rather quickly by mammals in the faeces.
T A B L E II. INFLUENCE OF ANILINE FORMATION TENDENCY OF
14C-LABELLED CHEMICALS ON THE FORMATION OF BOUND RESIDUESIN S O I L (outdoor conditions)
T A B L E VI. DISTRIBUTION O F 14C-RESIDUES OF I 4 C - H Y D R O X Y M O N O LINURON-j3-GLUCOSIDE IN T W O STERILIZED A N D NON-STERILIZED SOILSA F T E R 34 D A Y S (laboratory conditions; % of applied radioactivity)
H o w e v e r, in most cases the formation of u n e x t r a c table residues in soil cannot be correlated to a unique soil fraction. T h e r e f o r e, the q u e s t i o n of localizing the binding sites in soil has been a focus of research interest. T h e c l a s s i c a l fractionation scheme separating soil o r g a n i c matter into hum i n, humic acids and fulvic acids by alkaline treatment followed by acid p r e c i p i t a t i o n has been used by several authors [7, 18, 25, 26]. Bound pesticide r e s i d u e s were detected in all of these fractions. A more sophisticated f r a c t i o n a t i o n scheme is presented in F i g. 2.
FIG.3. Interlamellar binding of pesticides into expanding clay minerals.
those with sterilized soils , is a further indic a t i o n supporting this a s s u m p t i o n. C h e m i c a l structures suitable for such a kind of binding would be ionic or basic s u b s t a n c e s such as p h e n o l s or anilines.
FIG. 7. Correlation of formation of soil-bound residues with soil mineralization rates.
tabolite 3, 4 - d i c h l o r o a n i l i n e , the anilide carboxin in form of unchanged parent compound and of its sulfoxide m e t a b o l i t e . The triazine p r o m e t r y n is bound in form of its m o n o - and didealkylated m e t a b o lites .
 FRAGIADAKIS, A., Bilanz des Verhaltens von 14C-markiertem 2, 4, 6-Trichlorphenol in Pflanzen und Boden, Doctoral Thesis, Technical University of Munich, 1980.
 FRAGIADAKIS, A., et al., "Verhalten von Organohalogenverbindungen in Systemen Pflanzen-Boden", Organohalogenverbindungen in der Umwelt, Projektbericht 1975 — 1978 (zusammengestellt von FÜHR, F. and SCHEELE, В.), Spezielle Berichte der Kernforschungsanlage Jiilich, Nr. 45 (1975) 144.
IAEA-SM-263/38 203 FREITAG, D., Bilanz der Verteilung und Umwandlung von Monolinuron (Phenyl-14C) und Parachloranilin (- 14 C) im System Pflanze/Boden unter Freilandbedingungen, Doctoral Thesis, University of Bonn, 1977.
VISWANATHAN, R., et al., Longterm studies on the fate of 3, 4-dichloroaniline-14C in a plant-soil-system under outdoor conditions, J. Environ. Sci. Health B13 3 (1978) 243.
BOLLAG, J.-M., et al., Adsorption and transformation of four substituted anilines in soil, J. Agrie. Food Chem. 26 (1978) 1302.
PRESTEL, D., et al., Beitrâge zur ôkologischen Chemie CXXI, Bilanz der Verteilung und.Umwandlung von Metribuzin-14C (Sencor) in Kartoffeln, Mohren und Boden unter Freilandbedingungen, Chemosphere 5(1976) 137.
KHAN, S.U., Distribution of characteristics of boünd residues of prometryn in an organic soil, J. Agrie. Food Chem. 30 (1982) 175.
HAQUE, A., et al., Conversion of 14C-buturon in soil and leaching water under outdoor conditions, Pestic. Biochem. Physiol. 7 (1977) 321.
FÜHR, F., MITTELSTAEDT, W., Plant experiments on the bioavailability of unextracted (carbonyl-14C) methabenzthiazuron residues from soil, J. Agrie. Food Chem. 28 (1980) 122.
OGAWA, K., et al., Metabolism of 2-sec-butylphenyl-N-methylcarbamate (Bassa, BPMC) in rice plants and its degradation in soils, Nippon Noyaku Gakkaishi 1 (1976) 219.
KAZANO, H., et al., Metabolism of methylcarbamate insecticides in soils, J. Agrie. Food Chem. 20(1972) 975.
SPILLNER, C.J., et al., Degradation of fenitrothion in forest soil and effects on forest soil microbes, J. Agrie. Food Chem. 27(1979) 1054.
LICHTENSTEIN, E.P., et al., Binding of "persistent" and "non-persistent" 14C-labelled insecticides in an agricultural soil, J. Agrie. Food Chem. 25 (1977) 43.
LICHTENSTEIN, E.P., et al., A compartmentalized microcosm for studying the fate of chemicals in the environment, J. Agrie. Food Chem. 26 (1978) 948.
FUHREMANN, T.W., LICHTENSTEIN, E.P., Release of soil-bound methyH14C)-parathion residues and their uptake by earthworms and oat plants, J. Agrie. Food Chem. 26 (1978) 605.
KATAN, J., et al., Binding of (14C)-parathion in soil: a reassessment of pesticide persistence, Science 193(1976) 891.
AMBROSI, D., et al., Persistence and metabolism of phosalone in soil, J. Agrie. Food Chem. 25(1977) 342.
HELLING, C.S., KRIVONAK, A.E., Physico-chemical characteristics of bound dinitroaniline herbicides in soils, J. Agrie. Food Chem. 26 (1978) 1156.
GOLAB, T., AMUNDSON, M.E., "Degradation of trifluralin, oryzalin, and isopropalin in soil", Pesticides, Environmental Quality and Safety, Supplement Vol. Ill (COULSTON, F., KORTE, F., Eds), G. Thieme Publishers, Stuttgart (1975) 258.
SANDROCK, K., Bilanz der Verteilung und Umwandlung von Kelevan-14C und Kepone-14C in hoheren Pflanzen und Boden unter Freilandbedingungen, Doctoral Thesis, University of Bonn, 1974.
SANDROCK, K., et al., Beitrâge zur ôkologischen Chemie XLIII, Riickstandsverhalten und Umwandlung von Kelevan-14C unter simulierten praktischen Bedingungen in Kartoffeln, Chem. Mikrobiol. Technol. Lebensm. 1 (1972) 206.