Ciprofloxacin (CIP) is an antibiotic used in both human and veterinary medicine. Because it is only partially metabolized, it has been found in sewage sludge, manure, and agricultural soils. Therefore, due to the high persistence and low mobility of CIP in soil, we aimed to evaluate its long-term effect on Enchytraeus crypticus. Three multigenerational and one transgenerational test were performed according to OECD 220 guidelines (2016) on sandy clay soil. The concentrations tested were 0.1, 1.0, 10.0, 100.0, 1000.0 and 5000.0 mg kg- 1 dry soil. For F1, statistical analysis showed differences between the control and all concentrations tested, but no differences among the concentrations. For F2, there was a difference between control and 10 mg Kg -1 and for 10.0 mg Kg -1 compared to 0.1, 1.0 and 5000.0 mg Kg -1. For F3, no statistical difference was observed between any of the concentrations. When comparing the generations among themselves, there were significant differences between F1 and F2 and F1 and F3 for all concentrations. For the transgenerational test, there was no statistical difference between the control and the concentrations tested, nor among the concentrations. We verified a negative effect of CIP on the reproduction of E. crypticus for the first generation, which could be related to oxidative stress, DNA damage and clay content. We also verified that the organisms could develop a tolerance to CIP and that the effects of high clay content could outweigh the effects of CIP in long-term exposure. Due to the high persistence and low mobility of CIP on soil, it may affect other organisms and promote antibiotic resistant genes (ARGs) regardless of E. crypticus tolerance. Therefore, we strongly recommend further studies focusing on long-term effects on different organisms, with a molecular approach, and in different soil types.

The extensive use of non-biodegradable and petroleum derived polymers in industry exacerbates environmental problems associated with plastic waste accumulation and fossil resource depletion. The most promising solution to overcome this issue is the replacement of these polymers with biodegradable and bio-based polymers. In this paper, novel biocomposites were prepared from bio-based polyamide 5.6 (PA56) with the addition of olive stone powder (OSP) at varying weight concentrations by melt compounding method. The degradability of the prepared biocomposites is investigated through soil burial test, and assessed by reduction in their mechanical properties. The biodegradability of bio-based polyamide 5.6 is shown to be improved by addition of olive stone powder, and its effects on the properties of polymer matrix are elucidated. The Fourier transform infrared (FTIR) spectrum of the biocomposites indicate the successful incorporation of OSP into PA56 polymer matrix. After six-month soil burial test, scanning electron microscopy and FTIR show the degradation of PA56 through morphological and structural changes, respectively. Differential scanning calorimetry reveals the changes in the transition temperatures of the polymer matrix and an increase in crystallinity. Thermogravimetric analysis is used on the biocomposite to determine the fraction of its components, polymer and biofiller, and the results show that 2.67% (w/w) of the polyamide 5.6 is biodegraded at the end of the six-month soil burial.