Gas chromatographic determination of technical pyrazon (5-amino-4-chloro-2-phenyl-3(2H)pyridazinone)

5-Amino-4-chloro-2-phenyl-3(2H)pyridazinone (common name pyrazon) is the active ingredient of herbicide formulations known under the trade names Burex, Chlorazine, Pyramin, Phenazon. Pyrazon content was evaluated using the internal standard 4-chloro-5-methylamino-2-phenyl-3(2H)pyridazinone. FID detector and glass column (50 × 0.25 cm) packed with 2% cyclohexane-di-methanol succinate on silanised Chromosorb G (80-100 mesh) were used. Technical products can contain two interesting impurities, the non-active pyrazon isomer 4-amino-5-chloro-2-phenyI-3(2H)pyridazinone and the unreacted 4,5-dichloro-2-phenyl-3(2H)pyridazinone, the later of which issignificant from the point of view of toxicology. Determination of these two compounds under the conditions used for pyrazon is practically impossible. They were therefore determined on a separate glass column (70 × 0.24 cm) packed with 5% cyclohexane-di-methanol succinate on Chromosorb G (60-80 mesh). A standard addition method for small concentrations of 4,5-dichloro-2-phenyl-3(2H) pyridazinone in technical pyrazon products is also described.     

Foreign substances in the meat and organs of bulls and pigs fed with pastes made from household and food industry waste in addition to pastes made from poultry droppings

The residues of antimicrobial substances, some chlorinated and organophosphate pesticides and chemical elements were studied in the meat and organs of a group of bulls fed food-waste paste for 240 days and a group of bulls fed the same paste with an addition of poultry waste. These residues were also studied in the tissues of pigs fed the food-waste paste for 135 and 151 days until slaughter. The feed ingredients were also examined during the feeding trials. Although some of the residues under study were found in the tissues of the test animals at increased amounts, their concentrations were diluted in the tissues in the majority of cases when the feed pastes were administered. All residue contents recorded in the tissues remained below the permissible limits as given in valid instructions and directives so that the products, i. e. meat and organs, could be deemed digestible on the basis of hygienic evaluation. Hence, from the point of view of the occurrence of residues of foreign substances in edible tissues, the administration of food-waste pastes to farm animals can be considered as admissible.     

Identification of Escherichia coli from shellfish and related environments by automicrobic system

A total of 463 fecal coliform positive isolates obtained from shellfish and related samples gave typical Escherichia coli IMViC reactions. E. coli identifications for 458 (99%) of these isolates were confirmed using a combination of the Automicrobic System (AMS) and the API 20E system (reference system). The AMS (test system) identified 433 isolates as E. coli; the remaining 25 (5%) isolates were identified as E. hermanii by the test system and as E. coli by the reference system. Additional tests performed on the isolates identified as E. hermanii confirmed those AMS identifications to be incorrect.     

Determination of zearalenone in grains using high pressure liquid chromatography

The determination of zearalenone content in cereals (maize, wheat and barley) was performed by means of liquid chromatography using the Czechoslovak-made apparatus. This method enables to determine this mycotoxin up to the concentration of 8 micrograms per 1 kg of grain with the accuracy exceeding +/- 9%.     

Spectrophotometric method for differentiation of cardiac and hepatic lactate dehydrogenase activities in dogs

To differentiate the origin of high total lactate dehydrogenase (LD) activity in canine sera, a spectrophotometric method based on the preferential inhibition of cardiac LD isoenzymes by pyruvate was performed. Comparison with the electrophoretic separation of LD isoenzyme activities and determination of the hydroxybutyrate dehydrogenase-to-LD ratio indicated that the method proposed gave a better discrimination between cardiac and hepatic LD activities than did the other tests.     

Effect of clear-felling on runoff in two small watersheds in Central Sweden

Small watersheds were used in a study of the effect of clear-felling on runoff from coniferous forest areas in Central Sweden. After a 3-year calibration period, two watersheds were clear-felled (on one of them the slash was left and on the other slash was removed) and a third was left as a reference.Runoff under forested conditions was 271 and 246 mm year^?1, respectively for the treated watersheds, while the precipitation measured 732 mm year^?1 as a mean for the investigated period. Clear-felling resulted in an increase in runoff of 119 and 75% (371 and 215 mm per year), respectively. The increase occurred during the period of snowmelt (April–May) and the period without snow (June–October). During winter (November–March) a very small increase in runoff was noted. The effect of clear-felling on runoff appears to be greater than has been reported from most other Scandinavian investigations.The increase in runoff during snowmelt is probably due to an increased snow accumulation in the clear-felled area as compared to the forest. The increased runoff for the period without snow is explained by reduced transpiration from the vegetation and reduced evaporation caused by an increased aerodynamic resistance.No effects of slash removal could be detected, probably because of the natural variation between the two treated watersheds.