«: 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 ...»
 KEARNEY, P.C. et al., Res. Rev. 29 (1969) 137.
 FABIG, W., OTTOW, J.C.G., Arch. Hydrobiol. 85 (1979) 372.
 FABIG, W. et al., Eur. J. Appl. Microbiol. Biotechnol. 9 (1980) 133.
METABOLISM OF C-CHLORFENVINPHOS
IN R A P E PLANTS
unextracted residue fraction was treated as follows:
(1) Hydrolysis with 0.7% KOH and precipitation with ethanol, which released
0.04 ppm in saccharide solution and 0.01 ppm in starch precipitate (2) Hydrolysis with 17.5% NaOH and precipitation by acidification, which released 0.01 ppm in hemicellulose precipitate ( 3 ) Digestion with concentrated HCl, which released no radioactivity, either in the cellulose precipitate obtained by neutralization or in the neutralized solution. The remaining solids, believed to be lignins, contained 0.04 ppm, which constituted 12.1% o f the total radioactive residue found in the stems at harvest.
MICROBIAL D E G R A D A T I O N O F T H E
INSECTICIDE AZINPHOS-METHYLP. R. WALLNÔFER, G. ENGELHARDT, W. ZIEGLER Bayerische Landesanstalt für Bodenkultur und Pflanzenbau, Munich L. OEHLMANN, K. WAGNER Forschung und Entwicklung, Bayer AG, Leverkusen, Federal Republic o f Germany Azinphos-methyl (0,0-dimethyl-S-(4-oxo-l,2,3-benzotriazine-3[4H]-ylmethyl)-phosphorodithioate; trademark ®Guthion or ®Gusathion) is a widely used non-systemic insecticide for the control o f plant-sucking insects. Since it is used in large crop areas significant amounts will directly contaminate the soil during the application.
During a search for soil microorganisms capable o f degrading azinphosmethyl, Pseudomonas DSM 1976 was selected because o f its ability fluorescens to form different metabolites from azinphos-methyl [1 ]. The results presented here clearly show that P. fluorescens DSM 1976 is able to degrade the organophosphorous insecticide azinphos-methyl. Formation o f bis-(benzazimidyl-methyl)disulphide is most probably the result o f a simple hydrolysis o f the sulphurphosphorus bond o f the starting compound leading to thiomethyl-benzazimide, a metabolite which is readily oxidized enzymatically to bis-(benzazimidyl-methyl)disulphide (Figs 1,2).
Azinphos-methyl obviously is degraded to benzazimide via enzymatic oxidation. However, the most significant reaction type of azinphos-methyl degradation by P. fluorescens DSM 1976 is the cleavage o f the heterocyclic ring, thus forming anthranilic acid. Anthranilic acid is not degraded further by P. fluorescens DSM 1976. It is, however, easily metabolized via catechol by several other Pseudomonas strains or via gentisic acid by Nocardia . As no anthranilic acid was detected in cultures o f P. fluorescens DSM 1976 grown in the presence of benzazimide, it is suggested that anthranilic acid is formed from an intermediate other than benzazimide, presumably from bis-(benzazimidylmethyldisulphide or thiomethyl-benzazimide.
Benzazimide is considered to be the main metabolite o f azinphos-methyl during the degradation in soil . Degradation studies with this metabolite have so far failed although some indications exist for the transformation o f this compound by selected soil microorganisms.
POSTER PRESENTATIONS 307
FIG. 1. Degradation of azinphos-methyl by different Pseudomonas and Arthrobacter species (incubation period 10 d).
FIG. 2. TLC-scanning of metabolites formed during degradation of í4C-azinphos-methyl (I) by Pseudomonas fluorescens DSM 1976: bis-(benzazimidyl-methyl)-disulphide (IIh benzazimide (III), and anthranilic acid (IV); solvent system: toluene-acetone-triethylamine, 8:2:1 (vol. /vol./vol.).
 ENGELHARDT, G. et al., FEMS Microbiol. Lett. 11 (1981) 165.
 KIESLICH, К., Microbial Transformations of Non-Steroid Cyclic Compounds, Thieme, Stuttgart (1976).
 SCHULZ, K.R. et al., J. Econ. Entomol. 6 3 ( 1 9 7 0 ) 4 3 2.
PERSISTENCE O F A T R A Z I N E METABOLITES
IN SOIL A F T E R A SINGLE APPLICATIONP. CAPRIEL, A. HAISCH Bavarian State Institute for Soil and Plant Cultivation, Munich, Federal Republic o f Germany The fate o f atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) in soil was investigated under field conditions. In spring 1973 culture boxes (1 50 X 30 X 4 8 c m ) filled with naturally grown soil were buried in soil and the surface area o f the soil was treated with 25.6 mg 14 C-ring-labelled atrazine.
Between 1973 and 1981 different plants were cultivated in these culture boxes.
In summer 1981 soil samples were collected and analysed. Eighty-three per cent o f the initial 14C activity persisted in soil. The metabolites identified in the soil samples were: diethylatrazine (2-chloro-4-amino-6-isopropylamino-s-triazine) in less than phytotoxic amounts, 2-chloro-4,6-diamino-s-triazine, hydroxyatrazine (2-hydroxy-4-ethylamino-6-isopropylamino-s-triazine), diethylhydroxyatrazine (2-hydroxy-4-amino-6-isopropylamino-s-triazine) and diisopropylhydroxyatrazine (2-hydroxy-4-ethylamino-6-amino-s-triazine).
Data show that a single application o f atrazine results in the persistence o f some o f its degradation products, mainly hydroxylated analogues, in soil even 8 years after herbicide application. N-dealkylation and hydrolysis reactions were involved in the breakdown o f atrazine in soil. Only 50% of the 14C activity present in the soil samples could be extracted. This suggests that the atrazine metabolites are strongly bound to the soil complex and probably slowly set free. The metabolism o f atrazine leading to harmless products, such as carbon dioxide, ammonia or water, is surely a slow process. It is conceivable that longterm annual applications o f atrazine for weed control result in accumulation o f metabolites in soil, which could possibly affect the soil biochemistry.
EFFECT AND PERSISTENCE
OF C A R B A R Y L IN SOILSN.B.K. MURTHY, K. RAGHU Biology and Agriculture Division, Bhabha Atomic Research Centre, Bombay, India The effects o f carbaryl and 1-naphthol residues in soils on plant growth and microbial activities were investigated. Carbaryl had no phytotoxic effect at normal field concentrations. There was a gradual decrease in the seedling height o f barley with higher concentrations o f carbaryl in soil. Stimulation in plant height was observed with 1-naphthol. The nodule number in peanut plants was increased at
2.5 and 25 mg/kg levels o f carbaryl and 1-naphthol. Carbaryl reduced the nodule number at higher application rates. There was stimulation in soil microbial numbers with carbaryl. The increase in fungal and bacterial numbers was seen up to the first 7-d incubation period only. Soil respiration was enhanced in carbaryl-treated moist (aerobic) soil; however, in flooded (anaerobic) soil there was less C 0 2 production. 1-naphthol in aerobic soil increased C 0 2 production and decreased it in anaerobic soil. Soil dehydrogenase activity was not affected by carbaryl and 1-naphthol in aerobic soil.
The persistence o f 14 C-carbaryl was studied in black clay loam soil under aerobic and anaerobic conditions for 56 d. The extractable radioactivity was less in aerobic than in anaerobic soil; by the end o f the 56-d incubation period
1.9 and 4 1. 1 % remained in aerobic and anaerobic soils, respectively. Carbaryl was degraded both in aerobic and anaerobic soils. 1-naphthol was identified as the degradation product in anaerobic soil by TLC. More 14C02 was produced in aerobic than in anaerobic soil. Carbaryl was less stable in alkaline than in acid soil.
310 POSTER PRESENTATIONS IAEA-SM-263/55
Badruddin MAHBUB Water Quality and Environment Division, Institute o f Hydraulic Engineering, Bandung, Indonesia Various methods are used for evaluation o f water pollution, i.e. physical, chemical and biological, and productivity. The relation of physical and chemical parameters to biological and productivity parameters is not yet clearly known.
In this study measurements were taken on the various physical and chemical parameters and primary productivity (by the 14C method) [ 1 ] and the algal growth potential .
Investigations were carried out in the Citarum river, which receives a considerable amount o f pollutants originating from human and industrial wastes and from silt due to erosion. This river is dammed downstream to form the Jatiluhur reservoir. The site of investigation covers the area upstream of the river, down to the reservoir and beyond. These investigations were carried out during the wet and dry seasons in the years 1979-1982.
Based on statistical multivariate analysis, it has been concluded that a close relationship exists between all physical and chemical parameters to primary productivity (PP) and algal growth potential (AGP); either it is a relationship o f nutrients or o f depression due to toxic characteristics. Results o f the correlation formula prove that the primary productivity and algal growth potential form parameters which can be considered as water pollution indicators.
The results o f studies on water quality, primary productivity and algal growth potential indicate that the Citarum river has a high silt content, especially during the wet season, which depresses primary productivity. Starting upstream, water pollution originating from human and industrial waste from Bandung and its vicinity causes a high content o f nutrients, consequently increasing primary productivity, but the toxic content is quite high, even resulting in a reduction o f algal growth potential. However, after the river has flowed 100 km downstream and approaches the J atiluhur reservoir a process o f self-purification takes place, which improves the water quality, as indicated by an increase o f PP and AGP.
The water quality becomes even better in the Jatiluhur reservoir due to the sedimentation o f silt, resulting in a significant increase in PP. After passing POSTER PRESENTATIONS 311 through the reservoir the pollution process starts again, owing to silt and industrial waste, resulting in a reduction o f PP.
From the aspect o f productivity, water o f the Citarum river is able to selfpurify itself against the influence o f pollution and toxic contents, but the additional nutrient content has created another problem in the reservoir because it generates a process o f eutrophication.
This work was carried out with the support and co-operation o f the IAEA, Research Contract No. 2 3 9 3 / R I / S D, and the Ministry o f Public Works, Indonesia.
The author would also like to thank the Research Centre for Nuclear Techniques in Bandung for the I4C counting.
 LEHMUSLUOTO, P.O., Introduction to Phytoplankton Primary Productivity in Waters, UNDP OTC/SF Project (1977).
 LEHMUSLUOTO, P.O., Introduction to Algal Assays in Water Research, UNDP OTC/SF Project (1977).
EFFECT O F C O M M O N INSECTICIDES
O N NITROGEN-FIXING O R G A N I S M S
IN N O R T H IRAQI SOILSM.F.A. KHAN, K.G. SHALI Department o f Soil Science, College o f Agriculture, University o f Salahaddin, Aski Kalak, Iraq North Iraq is by and large different from the rest o f the country regarding the factors that control plant growth, such as soil, temperature and its variations, water regime, pests and diseases. Quite a large part o f the region is fairly rich in horticultural crops; thus, the potentiality of higher production from land 312 POSTER PRESENTATIONS resources has a bright future here. This is mainly due to g o o d soil fertility with respect to soil organic matter and native soil nitrogen. Preliminary investigations have suggested that such a condition is mainly due to the abundance o f effective nitrogen-fixing organisms in most north Iraqi soils [ 1 ]. Close examination o f individual organisms has shown that various species o f the free-living bacteria are particularly active in Sulaimaniyah Governorate soils .
Azotobacter Vicia faba has also been reported to significantly enrich the soil in nitrogen when inoculated with a local strain o f Rhizobium . Similarly, leguminosarum numerous blue-green algae have been found to fix large amounts o f atmospheric nitrogen .