Uptake of Ivermectin from Growing Substrate to Plant Species

SAUMELL CARLOS; ZEGBI SARA; SALLOVITZ JUAN MANUEL; SAGUES FEDERICA; IGLESIAS LUCIA; JUNCO MILAGROS; LIFSCHITZ ADRIAN

Congreso; 27 th Conference of the World Association for the Advancement of the Veterinary Parasitology; 2019

WAAVP

Ivermectin (IVM) is a widely used antiparasitic drug. In addition to its high fecal elimination, IVM transference from dung pats to the underlying soil and the use of manure as soil amendment represent a potencial risk to plants growing in these substrates. We conducted two trials in order to evaluate the uptake of IVM: 1) in a crop of Lolium multiflorum (ryegrass) and Trifolium repens (clover) that grew in IVM-spiked soil at 3000 (High group, HG) and 90 ng/g (Low group, LG) for 120 days post-treatment (dpt); and 2) in a crop of Raphanus sativus (radish) and Lactuca sativa (lettuce) that grew for 60 dpt in a composted soil-manure spiked at 3000 ng/g. Soil, composted soil and plants were sampled starting at 15 dpt and until the final time of culture. All matrices were analyzed by HPLC to quantify IVM concentrations. 1) In soil from the HG, IVM concentration decreased from 2154 ng/g to 225 ng/g throughout the sampling period, and mean IVM concentration in ryegrass ranged between 378.65 ng/g and 21.74 ng/g. Strikingly, clover development was delayed until 30 dpt. IVM concentration in this species ranged between 94.09 ng/g and 4.56ng/g. Statistical differences between species were significant (p=0.0374). In the LG, IVM concentration was between 22.26 and 1.02 ng/g in ryegrass and between 10 and 1.02 ng/g in clover, without statistically significant differences between species (p=0.8301). 2) IVM was detected in both radish and lettuce species (p>0.05) in all the sampling times; mean IVM concentration was between 10 ng/g and 5 ng/g , and between 17.70 ng/g and 6.55 ng/g, respectively. IVM concentration in the substrate decreased from 1311 ng/g to 116 ng/g. In conclusion, IVM in soil or composted substrate is transferred to the plants during their growth period, and can potentially be incorporated into the food chain of both livestock and humans.