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«: 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 ...»

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При длительном действии РЬ с концентрацией 0,5 мг/л в клетках Nitellopsis obtusa снижается уровень АТФ, доступной для энергообеспечения движения протоплазмы, и на десятые сутки опыта погибает 50% клеток. Пороговой концентрацией РЬ для клеток Nitellopsis obtusa следует считать 0,02 мг/л, а критической — 0,5 мг/л.

Сточные воды ЦБП при концентрации 0,4% вызывают у клеток Nitellopsis obtusa значительное, но у отдельных клеток обратимое снижение МП (до 70 мВ). В 6 % - о м растворе этого загрязнителя МП снижается до величин К — Na-диффузионных потенциалов (— 150 мВ), а в 12%-ом растворе — до величин близких к потенциалу оболочки (около — 70 мВ). Таким образом, сточные воды при концентрации от 0,4% до 12% индуцируют снижение или полное подавление той части МП клеток Nitellopsis obtusa, которая определяется работой электрогенных насосов. В 12%-ом растворе этого загрязнителя, по-видимому, начинается деструкция клеточных мембран, обуславливающая снижение МП до уровня потенциала оболочки. При длительном действии 3%-го раствора сточных вод ЦБП в водорослях уже снижается уровень АТФ, доступного для энергообеспечения движения протоплазмы. В 12%-ом растворе сточных вод на 16-е сутки опыта погибало 5 0 % клеток. Пороговой концентрацией сточных вод ЦБП для клеток Nitellopsis obtusa следует считать 0,4%, а критической — 12%.

ДЦТ в концентрациях 0,03 мг/л, 0,3 мг/л и 3,0 мг/л вызывают у клеток Nitellopsis obtusa различные биоэлектрические реакции: в одних клетках возникают колебания МП, в других же — волнообразная деполяризация или гиперполяризация на 10-20 мВ, а некоторые клетки не реагируют на присутствие ДЦТ, что может свидетельствовать о замедленном токсическом действии этого пестицида на клеточные мембраны и биоPOSTER PRESENTATIONS энергетическую активность водорослей. При длительном действии ДЦТ на клетки Nitellopsis obtusa достоверное снижение подвижности протоплазмы происходит при концентрации 0,3 мг/л, гибель отдельных клеток — при концентрации 3,0 мг/л, а гибель 5 0 % клеток, которая отмечена в первые семь суток опытов, — при концентрации 30 мг/л. Пороговой концентрацией ДЦТ для клеток Nitellopsis obtusa следует считать 0,03 мг/л, а критической — 3,0 мг/л.

При повышении температуры водной среды (до 30° С) происходит ухудшение физиологического состояния водорослей Nitellopsis obtusa, что выражается в снижении скорости движения протоплазмы и гибели отдельных клеток растений, а также подавлении образования и роста верхушечных клеток. Повышенные температуры водной среды (до 25-29° С) в основном не оказывают существенного влияния на уровни накопления 9 0 Sr и l37 Cs в водных растениях и несколько увеличивают уровни накопления 210РЬ и 144 Се в них, а также поступление этих радионуклидов, особенно 210 РЬ, в растительные клетки. Разница в накоплении радионуклидов в водных растениях при действии термального загрязнения, по-видимому, связана, главным образом, с различным физико-химическим состоянием этих радионуклидов как в водной среде, так и в самих растительных клетках. Повышение температуры водной среды увеличивает токсическое действие Pb на водоросли.

^Sr, 131 Cs и 144 Се (в диапазоне концентраций 37 • 10~6 - 3 7 • 10~4 Бк/л) на популяции хлореллы действуют подавляюще, при этом повышается число летально поврежденных и мутантных клеток. Однако, эти радионуклиды по их физиологическому и генетическому действию на популяции хлореллы весьма различаются. Если 144 Се, КН которого в хлорелле достигает 273 000 ед. и который в растительных клетках в основном аккумулируется на оболочке, несколько сильнее действует на интенсивность фотосинтеза и на число летально поврежденных клеток, то 9 0 Sr, КН которого в хлорелле равняется лишь 60 ед. и который в растительных клетках интенсивно накапливается и во внутриклеточных компартментах, сильнее действует на плотность клеток и изменения числа мутантных клеток, чем I37 Cs (КН 350 ед.) и 144Се. Различия в действии 90 Sr и I37 Cs, который, как и ^ S r, в растительных клетках интенсивно накапливается во внутриклеточных компартментах, по-видимому, можно объяснить неодинаковым физико-химическим состоянием этих радионуклидов, как аналогов Са и К, в протоплазме растительных клеток. Следовательно, степень действия радионуклидов (в пределах концентраций 37 • 10~6 - 3 7 • 10~ 4 Бк/л) на популяции хлореллы, особенно на плотность клеток и число мутантных клеток, главным образом, зависит от места локализации радионуклидов в ее клетках, которое в свою очередь обусловлено физико-химическим состоянием радионуклидов в водной среде и клетке, и в значительно меньшей степени — от величин КН радионуклидов в них.





POSTER PRESENTATIONS 321 IAEA-SM-263/22

MICROORGANISMS F R O M AN AQUATIC ECOSYSTEM

Dichlobenil interaction R. S O V U A N S K I, Z.K. SMIT, M. CONEK Institute o f Plant Protection, Faculty o f Agriculture, University o f Novi Sad, Novi Sad, Yugoslavia Granular dichlobenil was applied to an isolated portion o f two irrigation channels at a rate to give a final concentration o f 1 ppm for the control o f macrophytes which impede water flow. The dominant plants Ceratophyllum spicatum, Ranunculus circinans and demersum, Myriophyllum Potamogeton were suppressed. Despite a significant reduction in the fresh weight pectinatus o f submersed plants, i.e. 86.6 and 75.2% in the two channels, respectively, no significant drop in dissolved oxygen was noticed, but the pH o f the water increased to 9. A slight increase in the number o f amonifiers occurred between the 5th and 14th day after treatment, and an increase in fungi number was also noticed.

Disappearance o f dichlobenil from the water was rapid, with the rate dependent on conditions in the channel. The concentration in water was below the detectable level on the 14th and 28th day, respectively, in the two channels.

The highest concentration was found on the 2nd and 3rd day after application.

Accumulation in water plants was observed from the 3rd day and in bottom sediment from the 7th day onwards after treatment.

T o investigate the influence o f dichlobenil on consumer activity, fresh channel sediment was used and BOD was measured, using the conventional manometric technique with Warburg apparatus. The low concentration o f 1 ppm showed a stimulatory effect after 50 h incubation. For a concentration o f 10 ppm 100 h were needed for adaptation; for 100 ppm no increase in oxygen consumption was recorded, remaining below the values o f the control.

An accepted method for testing the toxicity o f industrial contaminants on microorganisms has been tried to assess the toxicity o f herbicides [1]. This method showed slight toxicity at the 1 ppm concentration o f dichlobenil and was higher at 10 ppm. The toxicity increased after 40 h, which could indicate that more toxic substances were generated.

T w o selected organisms were used, namely the fungi P. lilacinum Thom and sp. 15, which were isolated by the enrichment technique [2] with Aspergillus labelled dichlobenil and checked by autoradiography as it was hoped that they

POSTER PRESENTATIONS

would be capable o f accumulating the herbicide. They showed a positive reaction in the amidase test. Respiration measurements with Warburg apparatus showed the ability o f the tested species to use benzamide, 2,6-dichlorobenzamide and 2,6-dichlorobenzamide as a carbon source. The 2,6-dichlorobenzamide was shown to be the least prominent. In the presence o f glucose, as an alternative substrate, the first two chemicals increased oxygen consumption, but at a lower level than pure glucose; in the case o f dichlobenil the consumption was higher.

By autoradiography several species were isolated which belonged to the genera Pénicillium, Aspergillus, Fusarium, Trichoderma, Phoma and Coniothyrium.

T o obtain information on possible metabolism a study in pure culture with labelled.dichlobenil was conducted. The autoradiography o f silica gel F TLC plates indicated microorganisms capable o f degrading dichlobenil.

The main metabolites in pure culture were 2,6-dichlorobenzamide and 2,6-dichlorobenzoic acid. Another five labelled metabolites were also detected in co-metabolism studies but their identification has not yet been carried out.

–  –  –

[1 ] OFFHOUSE, K., Miinchener Beitràge zur Abwasserfischerei und Flussbiologie, Band 24R (1973) 176.

[2] KOKKE, R., Anthonie van Leeuwenhoek, J. Microbiol. Serol. 36 (1979) 189.

IAEA-SM-263/3

ANALYSIS OF R A D I O L A B E L L E D XENOBIOTICS

AND THEIR METABOLITES BY HIGH

PERFORMANCE LIQUID C H R O M A T O G R A P H Y

J. McDOUGALL, J.C.T. LANG, B.D. CAMERON Inveresk Research International Limited, Musselburgh, United Kingdom High performance liquid chromatography (HPLC) has been extensively used in the last decade for drug and pesticide analysis. Classical TLC, by virtue of its ease o f operation and ability to separate compounds o f widely differing polarities, has c o m e to occupy a central role in studying the metabolism o f xenobiotics in animals and plants. HPLC has similar operating parameters but in many cases has the additional advantages o f more rapid analysis, greater sample POSTER PRESENTATIONS 323 capacity and superior resolution, and is thus well suited for studying the metabolic alterations in drugs and pesticides.

Examples are given o f the application o f radio-HPLC to the analysis o f radiolabelled novel chemicals and their metabolites in selected animal species. These HPLC analyses utilized straight phase and reversed phase systems often with the addition o f anionic or cationic surfactants.

Detection o f radiolabeled pesticide xenobiotics and their metabolites in HPLC eluate can be by continuous (e.g. continuous flow radioactivity detected) or discontinuous methods (e.g. eluate fraction collection and quantitation by an independent liquid scintillation counter).

HPLC analysis with radio-detection is suited for use in the following

applications:

(1 ) Qualitative and quantitative comparison o f xenobiotic metabolic profiles in various animal species and following different routes o f administration (2) Isolation and purification o f xenobiotic metabolites before identification by GC-MS (3) Stability/degradation studies (4) Pharmacokinetics o f unchanged test compounds.

IAEA-SM-263/l 1

STUDY OF THE EXCRETION, SECRETION

AND RETENTION OF AN ANTI-LIVERFLUKE

COMPOUND IN A L A C T A T I N G COW

R. KIRCHMANN, G. KOCH, R. V A N BRUWAENE, J. V A N K E R K O M Département de radiobiologie, Centre d'étude de l'énergie nucléaire, Mol M. WINAND Institut national des radioéléments, Fleurus, Belgium The metabolic fate o f a drug, 4,4',6,6'-tetrabromo-2,2'biphenyldiol-mono (dihydrogen phosphate), has been investigated in a lactating dairy c o w at the experimental farm o f the Belgian Nuclear Centre in Mol.

324 POSTER PRESENTATIONS

–  –  –

T A B L E I. CONCENTRATIONS OF ALAC-II IN DIFFERENT TISSUES OF

A COW A T SACRIFICE 14 D A Y S A F T E R ADMINISTRATION



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