Changes in Antibiotics Levels After Treating Poultry Litter and Their Effects on the Early Stages of Chicory Seedling Development.

VÉLEZ, C.; ALONSO, L.; OTERO, P.; WUNDERLIN D.A; ALMADA, N.; GANGE, J.M; BERNIGAUD, I.I.; MORAES, DANIEL A. DE; PODIO, N.S.

Dublin

Congreso; SETAC EUROPE 33rd ANNUAL MEETING; 2023

SETAC

Poultry litter (PL) is used as fertilizer because contains essential nutrients for crops. However, it has proven to be an important reservoir of pollutants, especially antibiotics (ATBs). ATBs can be accumulated in soils, being taken up by edible plants, entering the food chain with unknown environmental and human health risks. Thus, this work seeks: (1) to characterize the ATBs present in raw and treated PL to verify their drop upon self-heating processes; (2) to study the effect of treatment + ATBs on the germination of chicory seeds, verifying the phytotoxicity of treated PL containing ATBs on the early stages of seedling development. Thus, we used five methods of treatment: T1-Pile without cover and without turning; T2-Pile with cover and without turning; T3-Pile with cover and with turning; T4-Mini pile with cover and with turning; and T5-Pile without cover and with turning. ATBs in PL were extracted by salt-assisted solvent extraction and quantified by UPLC-MS/MS. Phytotoxicity assays were carried out by diluting samples (raw PL and T1-T5) with ultrapure water at three proportions (10, 50 and 100 g/L). Seeds were added to Petri dishes containing filtration paper and control and PL solutions (raw and T1-T5), and further incubated in the dark for 6 days (in triplicate). After 6 days of incubation, seedlings were harvested and dissected. Germination rate and lengths were recorded. Cotyledons, shoots, and roots from each Petri dish were pooled and dried to measure dry biomass, moisture, and specific lengths. Nine antibiotics were found in PL samples, being higher in raw PL but decreasing upon treatment in the following order: T4>T3>T2>T1>T5. Phytotoxic assays showed that all the samples at 50 and 100 g/L decreased the biomass of root, and both length and specific length of root and shoot with respect to control. T3 and T4 seem to be the least effective treatments to eliminate ATBs, showing the highest phytotoxicity with respect to other treatments, being the root and shoot parameters the most affected by the presence of ATBs in PL (average correlation -0.67, p<0.05). Thus, this study confirms that ATBs have negative effects on the early stages of chicory seedling development. Our current results also demonstrate that different PL treatments have diverse efficacy to eliminate them from polluted PL. Therefore, finding a good treatment to remove ATBs and other pollutants from PL looks needed to avoid negative effects on plants growing in amended soils.