The adsorption of atrazine (ATZ) onto pristine and aged polyethylene microplastics (MPs) was investigated in distilled water (DW) and hydroponic nutrient-enriched water (EW) to evaluate its phytotoxic effects on Lactuca sativa germination. Aged microplastics (AMPs) exhibited higher ATZ adsorption in both conditions: 0.646 mg/g (14.49%) in DW and 0.742 mg/g (15.87%) in EW, compared to 0.405 mg/g (9.08%) and 0.504 mg/g (10.78%) for pristine microplastics (PMPs), respectively. This increase was attributed to photodegradation-induced surface modifications on MP, including increased roughness and the formation of oxygenated functional groups. The phytotoxicity assays showed that ATZ adsorbed onto AMPs inhibited seed germination more severely, with a maximum inhibition of 34% at 2 mg/L, evidencing that microplastic aging enhances ATZ adsorption and increases toxicity risks in aquatic environments, particularly under eutrophic conditions. The combined presence of MP and ATZ resulted in greater toxicity, attributed to a synergistic effect, as observed in dry and wet mass inhibition. These findings indicate that pollutant interactions amplify negative impacts on plant development. Furthermore, ATZ primarily affects root growth through direct physical contact with MP rather than via desorption into water.

Purpose: Due to tannery high pollution potential, is has become necessary to investigate in new treatment technologies that use recycled solid wastes as tires that are abundantly present in the environment. The application of anaerobic biological processes offers several advantages compared to aerobic processes, including lower energy consumption, reduced sludge production, and a smaller footprint, in addition to the potential utilization of methane as a fuel. Methods: A pilot scale anaerobic fluidized bed reactor was implemented, using crushed tire scraps with diameters ranging from 2.00 mm to 2.83 mm as support material. Results and conclusion: The maximum COD removal efficiency achieved in the system was 77.79% in the first stage and 92.9% in the second stage, while methane production reached 2,930.5 mL. The tire scraps demonstrated efficiency as a support material for biofilm development, with microbial biofilm growth observed through optical microscopy, showing morphologies similar to cocci. Research implications: The implications of this study are to verify the possibility of treatment of tannery wastewater along with the possibility of reuse of an environmental pollutant as tire residues. Originality/value: After the literature research, no study has focused in anaerobic fluidized bed reactors using tire scraps as a support media for the treatment of tannery wastewater.