Remanence du parathion et du methylparathion dans tubercules de pomme de terre et dans le sol a la suite de traitements du sol

Résumé On présente les résultats des recherches effectuées pendant 4 ans, sur la persistence du parathion et du méthylparathion dans les tubercules de pomme de terre et dans le sol, à la suite des traitements du sol avec des préparations en poudre. On a effectué des déterminations pour la récolte de la même année et pour celle de l'année suivante, c'est-à-dire 6 mois et respectivement 18 mois après le traitement.En général, les résidus accumulés dans les pommes de terre ont varié entre 0,08 et 0,44 ppm. Le dépôt résiduel accumulé pendant 6 mois dans les pommes de terre présente des valeurs voisines de celles accumulé et après un intervalle de 18 mois.La quantité de substance toxique présente dans le sol au moment de la récolte a été de 3 à 6 fois plus grande que celle trouvée dans les tubercules récoltés du même sol, et elle a varié entre 0,27 et 0,58 ppm.

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Summary During 4 years, investigations have been carried out on parathion and methylparathion residues in potato tubers and in soil, following soil treatments with dust preparations. Determinations were made for the crop of the same year, as well as for that of the next year, i.e. 6 months and 18 months after the treatment, respectively. In all cases, except in one year, the residues which accumulated in potatoes 6 months later, had values close to those of the residual deposit accumulated after 18 months.At harvesting, the amount of toxicant available in the soil was 3 to 6 times larger than that found in potato tubers harvested on the same soil, and varied between 0.27–0.58 ppm.No evident differences between the amounts of parathion and methylparathion residues were found, and this suggests that the same degradation factor acts on both compounds.The precipitations played an important role; thus in years with low precipitations, the toxicant deposits increased in the soil and, implicitly, also in the tubers.

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Zusammenfassung Es werden die Ergebnisse einer vierjährigen Forschungsarbeit über die Verweildauer von Parathion und Methylparathion in der Kartoffelknolle und im Boden nach Bodenbehandlungen mit Stäubemitteln zusammengefaßt. Die Rückstandsanalysen wurden am Erntegut desselben Jahres, das heißt 6 Monate nach der Behandlung, und am Erntegut des nächsten Jahres, also 18 Monate nach dem Zeitpunkt der Behandlung, durchgeführt.Mit Ausnahme eines einzigen Jahres erreichte der Rückstand in der Kartoffelknolle in allen Fällen Werte zwischen 0,08 und 0,44 ppm. Die nach 6 Monaten in den Knollen festgestellten Rückstandswerte unterscheiden sich von den nach 18 Monaten nachgewiesenen nur unwesentlich.Im Boden wurden zur Zeit der Ernte drei- bis sechsmal höhere Rückstandswerte gefunden als in Knollen. Dieselben variierten zwischen 0,27 und 0,58 ppm.Die Rückstandswerte für Parathion und für Methylparathion zeigten keine deutlichen Unterschiede. Dies läßt auf die Einwirkung der gleichen Abbaufaktoren für beide Verbindungen schließen. Eine besondere Bedeutung unter den Klimafaktoren kam den Niederschlägen zu. In Jahren, in denen diese gering waren, wurden größere Rückstandswerte im Boden und auch in den Kartoffelknollen festgestellt.

     

The effect of feeding soya bean trypsin inhibitor and repeated injections of cholecystokinin on rat pancreas

The effects of dietary soya bean trypsin inhibitor (SBTI) and of the daily injection of pure CCK or porcine intedstinal extract have been studied on the rat pancreas. The following parameters were measured: weight, DNA, RNA, trypsin, chymotrypsin, amylase, lipase, insulin and glucagon. The effects of dietary SBTI on the level of gastrin in the antrum have also been studied. Oral SBTI and i.p. CCK caused similar hypertrophy and hyperplasia but not the same activities of the enzymes. It is suggested that SBTI stimulates the secretion of at least two gastro-intestinal hormones: CCK and gastrin.     

Preparation of additional monoclonal antibodies for detection and discrimination of potato virus Y isolates infecting potato

Summary Monoclonal antibodies (MAb) specific to potato virus Y (PVY) were obtained from hybrid cells produced by fusion of a non-secreting myeloma cell line with spleen cells from BALB/c mice immunized with isolate Bintje PVY^o. Six MAb were characterized. The reactions of the MAb have been assayed by indirect double-antibody sandwich enzyme-linked immunosorbent assay (ELISA-IDAS) against forty-nine PVY isolates and other potyviruses, representative of different potato areas in the world. All MAb reacted to at least some isolates in group O+C in ELISA-IDAS. One MAb did not react to any group N isolates. MAb 10E3 reacted to all isolates tested. Using standard double-antibody sandwich enzyme-linked immunosorbent assay (ELISA-DAS), two MAbs did not react to any isolates, one reacted to some isolates in group O+C and MAb 10E3 reacted to all isolates but two in group C. A mixture of MAb 10E3 and 1E10 detected all isolates in ELISA-DAS and sensitivity was improved over that obtained with polyclonal antibodies from antisera.     

Annual dynamics of persistent organic pollutants in various aquatic matrices: a case study in the Morava River in Zlín district,Czech Republic

Purpose

A multi-compartment monitoring study was performed to characterize the effect of environmental variables, such as temperature and water flow as well as sediment characteristics, on the distribution and transport of persistent organic pollutants (POPs) in a dynamic river system during 1 year in an industrial region in central Europe.

Materials and methods

Waterborne polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were assessed over a period of 1 year at five sampling sites in the Morava River in the Czech Republic. Contaminants were measured monthly in riverbed sediments, freshly deposited sediments, water samples and passive samplers.

Results and discussion

Sediments are the main carrier of POPs in the river. Distinguishable patterns of PAHs, OCPs and PCBs in sediment indicate that their origin is from distinct sources and different transport pathways. The PAHs were identified as the dominant contaminant group of compounds with a mean concentration in sediment of 5,900 μg kg^?1. Such concentrations are up to 10 times higher than in the Danube River, into which Morava drains. In contrast, mean concentrations of PCBs, hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethane and its breakdown products (DDTs) and hexachlorobenzene (HCB) of 6.0, 0.4, 4.2 and 6.0 μg kg¹, respectively, are similar to those in the Danube. With some exceptions, no significant difference in composition of surficial riverbed sediments and those collected using sediment traps was observed. Despite the presence of potential local pollutant sources, the differences in contaminant concentrations between sites in the region were in most cases not significant. Variations in POP concentrations in sediments are mainly induced by high flow events, whereas seasonal variability was not observed.

Conclusions

The changes in contaminant concentrations in Morava River sediments are induced by episodic high flow events that cause erosion of contaminant-containing particles and their deposition at suitable downstream sites.     

Interaction dynamics between a contaminated dredged sediment and extracting solutions of different nature

Purpose

The purpose of this work is to study the dynamics between the matrix of a contaminated marine sediment, its contaminants and various desorbing solutions by means of equilibrium tests, sedimentation trials and zeta potential, with the focus on assessing optimum enhancing solutions for decontamination purposes.

Materials and methods

The sediment samples were analysed to determine their physico-chemical characteristics: particle size distribution, solids concentration, total organic carbon (TOC), content of heavy metals, organic contaminants, mineralogical phases, zeta potential and buffer capacity. Twelve extracting solutions of different nature were used for equilibrium tests, in which the dynamic behaviour of the sediment was evaluated. Elemental analysis was carried out for the sediment samples and the solutions before and after the tests.

Results and discussion

The sediment was mainly composed of clay and lime, with a high content of iron, which has a strong influence on sorption-desorption processes. The sediment had a considerable buffer capacity at low and high pH values. The desorption of the metals was not proportional to pH. The highest decrease in the concentration of metals from the sediment was obtained with 0.2 M ethylenediaminetetra-acetic acid (EDTA) and 1 M nitric acid, while the lowest degree of metal extraction occurred in pure water and potassium iodide (KI).

Conclusions

The most important parameters for contaminant release were complexation ability of the solution for the sediment components and pH of the solution. A promising design for the remediation treatment for the investigated sediment includes complexation and strong acid agents.

     

Comparisons of the effects of acupuncture, electroacupuncture, and transcutaneous cranial electrical stimulation on the minimum alveolar concentration of isoflurane in dogs

OBJECTIVE: To compare the effects of acupuncture (AP), electroacupuncture (EA), and transcutaneous cranial electrical stimulation (TCES) with high-frequency intermittent currents on the minimum alveolar concentration (MAC) of isoflurane and associated cardiovascular variables in dogs. ANIMALS: 8 healthy adult female Beagles. PROCEDURE: Each dog was anesthetized with isoflurane on 4 occasions, allowing a minimum of 10 days between experiments. Isoflurane MAC values were determined for each dog without treatment (controls) and after treatment with AP and EA (AP points included the Large Intestine 4, Lung 7, Governing Vessel 20, Governing Vessel 14, San Tai, and Baihui) and TCES. Isoflurane MAC values were determined by use of noxious electrical buccal stimulation. Heart rate, mean arterial blood pressure (MAP), arterial blood oxygen saturation (Spo2) measured by use of pulse oximetry, esophageal body temperature, inspired and expired end-tidal isoflurane concentrations, end-tidal carbon dioxide concentration, and bispectral index (BIS) were monitored. Blood samples were collected for determination of plasma cortisol concentration. RESULTS: Mean +/- SD baseline MAC of isoflurane was 1.19 +/- 0.1%. Acupuncture did not significantly change MAC of isoflurane. Treatments with EA and TCES significantly lowered the MAC of isoflurane by 10.1% and 13.4%, respectively. The Spo2, heart rate, MAP, BIS, esophageal body temperature, and plasma cortisol concentration were not significantly different after AP, EA, TCES, and control treatments at any time interval. CONCLUSIONS AND CLINICAL RELEVANCE: Use of EA and TCES decreased MAC of isoflurane in dogs without inducing adverse hemodynamic effects. However, the reduction in isoflurane MAC by EA andTCES treatments was not considered clinically relevant.     

Do recreational fisheries metrics vary on differently sized fishing grounds?

This study aimed to assess the relationship between basic metrics in recreational fishing and the size of the fishing ground. Data were obtained from individual angling logbooks collected by the Czech Fishing Union over 12 years on 212 fishing grounds located in the regions of Prague and Central Bohemia in the Czech Republic. Small fishing grounds had the highest catch, yield, numbers of fishing visits and numbers of angling guard controls per hectare. Medium‐sized fishing grounds had the highest catch, yield, and numbers of both fishing visits and angling guard controls per fishing ground. Anglers returned to medium‐sized fishing grounds most frequently. The percentage of anglers who caught and took home at least one fish decreased with increasing size of the fishing ground. In conclusion, basic metrics in recreational fishing are related to the size of the fishing ground, which thus plays an important role in fisheries management.     

Biological Denitrification of High Nitrate Processing Wastewaters from Explosives Production Plant

Wastewater samples originating from an explosives production plant (3,000 mg N l⁻¹ nitrate, 4.8 mg l⁻¹ nitroglycerin, 1.9 mg l⁻¹ nitroglycol and 1,200 mg l⁻¹ chemical oxygen demand) were subjected to biological purification. An attempt to completely remove nitrate and to decrease the chemical oxygen demand was carried out under anaerobic conditions. A soil isolated microbial consortium capable of biodegrading various organic compounds and reduce nitrate to atmospheric nitrogen under anaerobic conditions was used. Complete removal of nitrates with simultaneous elimination of nitroglycerin and ethylene glycol dinitrate (nitroglycol) was achieved as a result of the conducted research. Specific nitrate reduction rate was estimated at 12.3 mg N g⁻¹ VSS h⁻¹. Toxicity of wastewater samples during the denitrification process was studied by measuring the activity of dehydrogenases in the activated sludge. Mutagenicity was determined by employing the Ames test. The maximum mutagenic activity did not exceed 0.5. The obtained results suggest that the studied wastewater samples did not exhibit mutagenic properties.     

Responses of deciduous forest trees to severe drought in Central Europe

In 2003, Central Europe experienced the warmest summer on record combined with unusually low precipitation. We studied plant water relations and phenology in a 100-year- old mixed deciduous forest on a slope (no ground water table) near Basel using the Swiss Canopy Crane (SCC). The drought lasted from early June to mid September. We studied five deciduous tree species; half of the individuals were exposed to elevated CO(2) concentration ([CO(2)]) (530 ppm) using a free-air, atmospheric CO(2)-enrichment system. In late July, after the first eight weeks of drought, mean predawn leaf water potential about 30 m above ground was -0.9 MPa across all trees, dropping to a mean of -1.5 MPa in mid-August when the top 1 m of the soil profile had no plant accessible moisture. Mean stomatal conductance and rates of maximum net photosynthesis decreased considerably in mid-August across all species. However, daily peak values of sap flow remained surprisingly constant over the whole period in Quercus petraea (Matt.) Liebl., and decreased to only about half of the early summer maxima in Fagus sylvatica L. and Carpinus betulus L. (stomatal down- regulation of flux). Although we detected no differences in most parameters between CO(2)-treated and control trees, predawn leaf water potential tended to be less negative in trees exposed to elevated [CO(2)]. Leaf longevity was greater in 2003 compared with the previous years, but the seasonal increase in stem basal area reached only about 75% of that in previous years. Our data suggest that the investigated tree species, particularly Q. petraea, did not experience severe water stress. However, an increased frequency of such exceptionally dry summers may have a more serious impact than a single event and would give Q. petraea a competitive advantage in the long run.