A hybrid monitoring and modelling approach to assess the contribution of sources of glyphosate and AMPA in large river catchments

Large river catchments with mixed land use capture pesticides from many sources, and degradable pesticides are converted during downstream transport. Unravelling the contribution of pesticide source and the effect of degradation processes is a challenge in such areas. However, insight and understanding of the sources is important for targeted management, especially when water is abstracted from the river for drinking water production. The river Meuse is such a case. A long-term monitoring data set was applied in a modelling approach for assessing the contribution of waste water treatment plants (WWTPs) and tributaries (sub-basins) to surface water contamination, and to evaluate the effect of decay on the downstream concentrations of glyphosate and AMPA at the point of drinking water abstraction. The results show that WWTPs are important contributors for glyphosate and AMPA in large river catchments with mixed land uses. In the studied area, the river Meuse in the Netherlands, the relative contribution of WWTP effluents is above 29% for glyphosate and around 12% for AMPA. Local industries are found to be potentially big contributors of AMPA. Glyphosate entering the river system is gradually converted to AMPA and other degradation productions, which results in downstream loads that are considerably lower than the sum of all influxes. In summer when the travel time is longer due to lower discharge, the first order decay of glyphosate in the river Meuse is estimated to result in about 50% reduction of the downstream glyphosate concentrations over a river stretch of 250km. The contribution of glyphosate decay to the observed AMPA concentrations ranges between 2% and 10%. Contributions are sensitive to seasonal variations in discharge that influence the concentrations through dilution and degradation.

Detection and determination of anabolic steroids in nutritional supplements

A method is described for the determination of anabolic steroids including testosterone, 19-nor-4-androstene-3,17-dione, 4-androstene-3,17-dione and nandrolone in food supplements. Initial clean-up is done by HPLC followed by determination with GC/MS. A 'contaminated' food supplement was analysed and appeared to contain 19-nor-4-androstene-3,17-dione and 4-androstene-3,17-dione. One capsule of this nutritional supplement was ingested by five male volunteers. Urine samples were collected and analysed by GC/MS and GC/MS-MS. Neither the ratio testosterone/epitestosterone, nor the ratio androstenedione/epitestosterone increased significantly. Concentrations above 2 ng/ml for norandrosterone, the major metabolite of nandrolone, were detected until 48-144 h after ingestion of the food supplement.

The abuse of doping agents in competing body builders in Flanders (1988-1993)

Analytical findings of unannounced doping control in body builders in Flanders during 1988-1993 are reported. In some federations between 38 and 58% of the controlled athletes were found positive during this period. The results show that there was no fall in drug abuse over this period and steroids were taken even by body builders associated with an organisation against the use of anabolic steroids. In 1988 and 1989 popular anabolic steroids were nandrolone and testosterone. From 1990 on, a wide range of mostly injectable steroids including nandrolone, metenolone, drostanolone and testosterone were administered. Polydrug abuse including several anabolics in combination with stimulants and diuretics was also widespread. The beta agonist clenbuterol was detected in several urine samples taken in 1991, one year before its appearance in other sports.

Comparative study of extraction methods for the GC and GC-MS screening of urine for beta-blocker abuse

Comparison is made between conventional liquid-liquid extraction and solid-phase extraction techniques using Extrelut-1, Extrelut-3 and C18-RP cartridges respectively for the screening of several beta-blockers in urine. Generally, using GC with nitrogen specific detection as the screening technique, liquid-liquid extraction and Extrelut-1 solid-phase extraction seem to be the methods of choice. However, when the screening and confirmation are performed by GC-MS, solid phase extractions with C18 or Extrelut-1 are valuable alternatives to conventional extraction. Using the different extraction techniques, detection limits and time periods during which the drugs are detectable in urine after oral administration of subtherapeutic amounts of several beta-blockers are determined.

Pharmacokinetics and diuretic effect of bumetanide following intravenous and intramuscular administration to horses

Concentrations of the potent diuretic bumetanide were determined by a sensitive high performance liquid chromatographic procedure in plasma and urine from horses following intravenous and intramuscular administration of a dose rate of 15 micrograms/kg. The elimination half-life was found to be 6.3 min, the volume of distribution at steady state 68 ml/kg and the total plasma clearance 10.9 ml/min/kg. The onset of diuresis occurred within 15 min and diuresis was no longer apparent 1 h after i.v. administration. Given by the intramuscular (i.m.) route, bumetanide was rapidly absorbed; bioavailability was 70-80%. i.m. administration of bumetanide prolonged its plasma half-life (11-27 min) and enhanced and prolonged its diuretic effect.