Effects of the Veterinary Pharmaceutical Ivermectin in Indoor Aquatic Microcosms

The effects of the parasiticide ivermectin were assessed in plankton-dominated indoor microcosms. Ivermectin was applied once at concentrations of 30, 100, 300, 1000, 3000, and 10,000 ng/l. The half-life (dissipation time 50%; DT50) of ivermectin in the water phase ranged from 1.1 to 8.3 days. The lowest NOECcommunity that could be derived on an isolated sampling from the microcosm study by means of multivariate techniques was 100 ng/l. The most sensitive species in the microcosm study were the cladocerans Ceriodaphnia sp. (no observed effect concentration, NOEC = 30 ng/l) and Chydorus sphaericus (NOEC = 100 ng/l). The amphipod Gammarus pulex was less sensitive to ivermectin, showing consistent statistically significant reductions at the 1000-ng/l treatment level. Copepoda taxa decreased directly after application of ivermectin in the highest treatment but had already recovered at day 20 posttreatment. Indirect effects (e.g., increase of rotifers, increased primary production) were observed at the highest treatment level starting only on day 13 of the exposure phase. Cladocera showed the highest sensitivity to ivermectin in both standard laboratory toxicity tests as well as in the microcosm study. This study demonstrates that simple plankton-dominated test systems for assessing the effects of ivermectin can produce results similar to those obtained with large complex outdoor systems

Development and validation of an UPLC-MS/MS method for the determination of ionophoric and synthetic coccidiostats in vegetables

In poultry farming, anticoccidial drugs are widely used as feed additives for the prevention and treatment of coccidiosis. Because coccidiostats and veterinary medicines, in general, are often poorly absorbed, manure from treated animals may contain high concentrations of these compounds. Experimental studies have shown that the uptake of veterinary medicines by plants from soil containing contaminated manure may occur. This leads to several questions regarding the impact on the environment, resistance problems, and public health and allergy issues. This work describes the development of a quantification method for coccidiostats in vegetables. Vegetables were spiked at 100 mu g kg(-1) (dry weight) with coccidiostats (monensin, narasin, lasalocid A, salinomycin, diclazuril, and nicarbazin) in order to optimize the extraction and clean-up. Possible critical factors (e.g., extraction solvent) were statistically examined by linear regression with the use of Plackett-Burman and full factorial designs. Final extracts were analyzed with ultra-performance liquid chromatography tandem mass spectrometry operating in multiple-reaction monitoring mode. Both the synthetic and ionophoric coccidiostats could be determined in a single run with an analysis time of 5 min. The developed method was validated taking into account the requirements of the Commission Decision 2002/657/EC as a guideline. The method is regarded as applicable for its intended purposes with quantification limits between 0.30 and 2.98 mu g kg(-1). This method could be used to establish possible maximum residue limits for coccidiostats in vegetables, as already exist for eggs, meat, and milk