ABSTRACT
As a carrier of environmental pollutants, microplastics have received wide concerns in recent years. However, the direct and indirect effects of the coexistence of polystyrene particles (PS) and pollutants on vegetables are still unclear. Here, the combined effects of 0.25, 0.50, 1.0 mg·mL-1 PS and 5 mg·L-1 dibutyl phthalate (DBP) on the biomass and biochemical indices of purple lettuce were investigated in hydroponic experiments. The results showed that the presence of PS increased the inhibition of DBP on lettuce biomass and increased O2-· content in roots and leaves relative to the control group with DBP alone, with positive consequences on the activities of supero-xide dismutase, ascorbic acid peroxidase, dehydroascorbate reductase and monodehydroascorbate reductase. According to transmission electron microscope analysis, plasmolysis occurred in root cells under the treatment of DBP alone, cell wall was damaged in PS-only treatment, and the negative effect was enhanced when DBP and PS coexisted. Therefore, the combined pollution of PS and DBP aggravated the toxic effect on purple lettuce.
Subject(s)
Dibutyl Phthalate , Lactuca , Polystyrenes , Dibutyl Phthalate/toxicity , Microplastics , Plastics , Polystyrenes/toxicityABSTRACT
Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.
