In 1997 the Flemish Environmental Agency (FEA) started a monitoring program "Pesticides in Rain in Flanders, Belgium". The original purpose of the monitoring program was to examine the possible occurrence of dichlorvos in rainwater and subsequent deposition. However, it was thought necessary from the beginning to monitor a wide range of pesticides. During the first year some 62 pesticides and metabolites and 9 polychlorinated biphenyls, were monitored at 4 locations. Nowadays the monitoring program has grown up to more than 100 pesticides and metabolites and 11 polychlorinated biphenyls examined at 8 different locations. Rainwater is collected continuously and samples are examined for pesticides and PCB's on a weekly basis. In agreement with other European studies pesticides are found in rainwater samples during times of application. Pesticides which are most frequently detected are [small alpha]-, [small beta]-endosulfan and endosulfan sulfate, [gamma]-HCH (lindane), dichlorvos, atrazine, diuron, DNOC, glyphosate and AMPA and isoproturon. Furthermore it was seen that most pesticides showed a deposition pattern related to local spraying operations.

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Short Communicationspeak represents either sinigrin itself or an other impurity from the sample overlapping with sinigrin. So it is evident, that glucotropaeolin is a better internal standard than sinigrin for the determination of glucosinolate content of oilseed rape by HPLC.HPLC methods will only detect intact glucosinolates. Glucosinolates degraded either enzymatically by myrosinase or thermally will not be determined by this method. In both cases the HPLC method detects a lower glucosinolate content. Figures 2 A and 2 B show the HPLC-chromatograms of a rapeseed sample untreated (A) and after heating to 110°C for 60 min (B). It is evident that the glucosinolate content in chromatogram B is lower. Especially the indolyl-glucosinolate 4-OH-glucobrassicin (peak 9) is very sensitive to heat and 50 % has already been destroyed. The alkenyl-glucosinolates are more stable and only 10 % of these have been lost.

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SummaryBlood thiamine levels and transketolase activities were studied both in normal and diseased cattle in order to establish some reliable laboratory diagnostic method for adequacy of thiamine supply in cattle.For several reasons a poor relationship was found between blood thiamine concentration, blood pyruvate and transketolase activity, expressed as TPP‐effect, as pentose substrate utilization or as sedoheptulose generation.Although combination of these different parameters is recommended to obtain more evidence, data on substrate utilization and/or metabolite generation by red blood cell‐transketolase should be adequate indices for the thiamine status in cattle.ZusammenfassungZur Diagnostik der Thiaminversorgung des Rindes durch Bestimmung des Thiamingehaltes und der Transketolase‐Aktivität im BlutZur Erkennung einer adäquaten Thiaminversorgung des Rindes wurde versucht, einen entsprechenden Labortest auszuarbeiten, indem der Thiamingehalt und die Transketolase‐Aktivität im Blut normaler und erkrankter Rinder bestimmt wurde. Aus verschiedenen Gründen wurde nur eine geringe Korrelation zwischen der Thiamin‐ und Pyruvatkonzentration sowie der Transketolase‐Aktivität (ausgedrückt als TPP‐Effekt oder Pentose‐Utilisation bzw. Sedoheptulosebildung) gefunden.Wenn auch eine Kombination der verschiedenen Parameter zur Erzielung eines vertieften Einblickes empfohlen werden kann, sollten doch die Daten über die Substratutilisation und/oder die Metabolitbildung durch die Erythrozyten‐Transketolase genügend Hinweise über die Thiaminversorgung der Rinder geben.RésuméA propos du diagnostic de la quantité de thiamine nécessaire pour le bovin par détermination du taux de thiamine et de l'activité de la transketolase dans le sangAfin de connaître un approvisionnement adéquat du bovin en thiamine, on a essayé de développer un test de laboratoire correspondant qui permettrait de déterminer le taux de thiamine et l'activité de la transketolase dans le sang d'animaux sains et malades. Pour diverses raisons, on a trouvé qu'une faible corrélation entre la concentration de la thiamine, du pyruvate et de l'activité de la transketolase (exprimé en effet TPP, utilisation du pentose et formation de sedoheptulose).Bien que la combinaison de ces différents paramètres soit recommandée pour obtenir une plus grande précision, les données sur l'utilisation du substrat et/ou la formation de métabolites par la transketolase des globules rouges devraient donner des indications suffisantes sur le statut de la thiamine chez le bovin.ResumenEl diagnóstico del suministro de tiamina en los vacunos mediante valoración del contenido en tiamina y de la actividad transcetolásica en sangrePara reconocer el suministro adecuado de tiamina en los vacunos, se intentó elaborar una prueba correspondiente de laboratorio valorando el contenido en tiamina y la actividad transcetolásica en sangre de reses vacunas sanas y enfermas. Por razones diversas se halló solo una correlación escasa entre las concentraciones de tiamina y de piruvato y la actividad transcetolásica (expresada como efecto TPP o utilización del substrato de pentosa resp. generación de sedoheptulosa). Aunque se puede recomendar la combinación de los diversos parámetros para conseguir una ojeada profunda, deberían aportar los datos sobre la utilización del substrato y/o la generación de metabolitos por la transcetolasa eritrocítica indicaciones suficientes sobre el estado de tiamina en los bovinos.