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Rombke J.,ECT Oekotoxikologie GmbH | Coors A.,ECT Oekotoxikologie GmbH | Fernandez T.A.,University of Alcalá | Forster B.,ECT Oekotoxikologie GmbH | And 5 more authors.
Applied Soil Ecology | Year: 2010

The effects of the parasiticide ivermectin on dung and soil fauna as well as dung decomposition were assessed in a field study conducted near Madrid (Spain). Groups of cattle were treated with an injection of Ivomec® at a dosage of 200μg ivermectinkg-1 body weight at four different time points before collecting the fresh dung of all cattle groups on day 0. Dung pats prepared from the dung of the ivermectin-treated cattle were exposed in the field from day 0 onwards in parallel with dung pats that were prepared from the dung of untreated cattle and that was either spiked with a high concentration of ivermectin (positive control) or not spiked (negative control). Ivermectin concentrations in freshly excreted dung ranged from 0.31 to 0.81mg ivermectinkg-1 dung dry weight. Ivermectin soil concentrations were highest below ivermectin-spiked dung in the uppermost soil layer with up to 0.085mg ivermectinkg-1 soil dw. No ivermectin-related effects on collembolans and mites were found. A significant decrease in the abundance of adult dung beetles was observed at 0.81mg ivermectinkg-1 dung dw, but the two most abundant species showed contrasting responses. For the dung beetle species, Volinus distinctus, a no observed effect concentration (NOEC) and a median effect concentration (EC50) of 0.50 and 0.62mg ivermectinkg-1 dung dw, respectively, were determined. Dung fly larvae were the most sensitive dung fauna group as their abundance was significantly reduced in all ivermectin treatments, resulting in a NOEC of <0.31mg ivermectinkg-1 dw. Staphylinid beetles were abundant in the dung, but apparently not affected by ivermectin. Dung from ivermectin-treated cattle degraded more slowly than dung from untreated cattle, resulting in a NOEC of <0.78mg ivermectinkg-1 dung dw for this functional endpoint. Adult dung beetles of both dominant species were attracted to dung pats spiked with ivermectin. The mobility of ivermectin appeared to differ between dung from ivermectin-treated cattle and dung spiked with ivermectin. This finding challenges approaches to assess the fate and effect of veterinary pharmaceuticals in higher tier tests by using spiked dung. This field study detected consistent results regarding effects of ivermectin on structural and functional endpoints in the dung compartment but effects on soil microarthropods are of little relevance in comparison. This study further advances guidance on higher tier tests that is required to make the results more applicable to the environmental risk assessment of veterinary pharmaceuticals. © 2010 Elsevier B.V.

Fernandez C.,INIA Spanish National Institute for Agricultural and Food Research and Technology | Porcel M.A.,INIA Spanish National Institute for Agricultural and Food Research and Technology | Alonso A.,INIA Spanish National Institute for Agricultural and Food Research and Technology | Alonso A.,University of Alcalá | And 2 more authors.
Environmental Science and Pollution Research | Year: 2011

Introduction: The antiparasitic ivermectin is of particular concern to regulatory agencies. Ivermectin can reach the environment through the direct emission of dung from livestock on pasture and via manure application on agricultural lands. Methods: A semifield study was conducted for assessing the ivermectin dynamic in runoff and drainage waters from dung-treated soils placed on experimental trays. The experiment was conducted under natural Mediterranean conditions. Realistic pasture and arable land applications were assessed using dung of treated animals and compared with a positive control (spraying the ivermective solution without dung). Results: Similar concentrations were obtained in all three treatments for drainage waters, with values ranging from <5-10 to about 20 ng/l. However, strong treatment-related variation was observed in runoff waters, with the highest concentrations found in the spray treatment (9-188 ng/l), followed by the arable land (<5-88 ng/l) scenario, and concentrations not exceeding 6 ng/l in the pasture scenario. Ivermectin levels in runoff particles were up to 1,660 and 5,890 ng/kg dry weight for the pasture (I1) and arable land (I2) scenarios, respectively. Ivermectin was only detected in the drainage and runoff waters collected in the first rainfall events after treatment. Conclusions: The measured concentrations in water (0.006-0.118 ng/ml) and runoff particles (0.052-5.89 ng/mg dry suspended matter) are orders of magnitude higher than those provoking effects on aquatic and benthonic communities under experimental and mesocosm conditions, suggesting a clear risk for aquatic systems in the vicinity of pasture areas of treated animals or arable soil fertilized with its manure. © 2011 Springer-Verlag.

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