Instituto Nacional de Limnología (INALI-CONICET-UNL), Ciudad Universitaria, Paraje El Pozo, 3000, Santa Fe, Argentina.
Facultad de Bioquímica y Ciencias Biológicas - Escuela Superior de Sanidad "Dr. Ramón Carrillo" (UNL), Ciudad Universitaria, Paraje El Pozo, 3000, Santa Fe, Argentina.
Arch Environ Contam Toxicol. 2018 Aug;75(2):316-326. doi: 10.1007/s00244-018-0539-5. Epub 2018 May 30.
Two anthelmintic macrocyclic lactones-ivermectin and moxidectin-have revolutionized parasite control in cattle. These drugs are only partly metabolized by livestock, and the main route of excretion is via feces. In seasonally inundated floodplains, cattle feces come into direct contact with surface water. Important differences in pharmacokinetics and pharmacodynamics between these drugs may bear on their ecotoxicology in aquatic ecosystems. Moxidectin strongly binds to organic matter and thereby may be consumed in aquatic food webs, but there is a scarcity of data on toxicity to freshwater invertebrates. The objectives of this work were to determine the effect of moxidectin spiked in cattle dung on survival and growth of three representative aquatic invertebrates: the zooplankton Ceriodaphnia dubia, the amphipod Hyalella curvispina, and the snail Pomacea canaliculata. Moxidectin-laced dung was added in microcosms and concentrations were measured in water, sediment + dung, roots of the aquatic plant Salvinia biloba, and the aforementioned invertebrates. The influence of moxidectin on nutrient concentrations was also evaluated. Dung was spiked with moxidectin to attain concentrations of 750, 375 and 250 µg kg dung fresh weight, approximating those found in cattle dung at days 2, 3, and 5 following subcutaneous injection. Concentrations of moxidectin in dung during the first week of excretion were lethally toxic for the tested invertebrate taxa. The persistence of moxidectin in the sediment + dung and the uptake of the drug in roots of S. biloba increase its potential exposure to aquatic food webs. Moxidectin also reduced the rate of release of soluble reactive phosphorus to the water.
两种驱虫大环内酯类药物——伊维菌素和莫昔克丁——彻底改变了牛寄生虫病的防治方式。这些药物在牲畜体内只有部分代谢，主要排泄途径是粪便。在季节性泛滥的洪泛区，牛粪便直接与地表水接触。这些药物在药代动力学和药效学方面的重要差异可能会影响它们在水生生态系统中的生态毒理学。莫昔克丁与有机物强烈结合，因此可能会被水生食物网消耗，但有关其对淡水无脊椎动物毒性的数据很少。本研究的目的是确定在牛粪中添加莫昔克丁对三种有代表性的水生无脊椎动物——浮游动物哲水蚤、食藻寡毛类霍氏真猛水蚤和蜗牛福寿螺——的生存和生长的影响。在微宇宙中添加了含有莫昔克丁的粪便，并测量了水中、粪便沉积物、水生植物满江红的根以及上述无脊椎动物中的莫昔克丁浓度。还评估了莫昔克丁对营养物质浓度的影响。向牛粪中添加莫昔克丁，使其达到 750、375 和 250μg/kg 鲜牛粪重量的浓度，这与皮下注射后第 2、3 和 5 天牛粪便中的浓度相近。排泄后第一周粪便中莫昔克丁的浓度对测试的无脊椎动物分类群具有致命毒性。莫昔克丁在粪便沉积物中的持久性和在满江红根中的摄取增加了其对水生食物网的潜在暴露。莫昔克丁还降低了可溶性反应性磷向水中的释放速度。
