Process analysis of asymmetric interaction between copper and atrazine in a system of macrophytes

To clarify the mutual influence and inner processes between heavy-metal and pesticide pollutants, single copper and atrazine as well as binary mixtures were spiked in a system of aquatic Acorus tatarinowi Schott. The results show that: the total copper amount in roots was 23.31 and 41.46 times as much as those in leaves in single and co-contaminated copper pollution. In the solution, the copper removal reached equilibrium in 3 days. Atrazine raised plant-mediated copper removal by 20.69 % by calculating mass balance, and the increase in pH value and organic matter and the decrease of nitrate in solutions were key factors driving it. Correlation analysis demonstrated that the pH increase was mainly caused by the decline of nitrate and increases in organic matter in the solution. Hydroxyl units on the surface of organic matter in solutions provided binding sites for Cu²⁺, which was demonstrated by CO and OH peak position alterations in Fourier Transform Infrared Spectrometer. In turn, the root contained 2.56 and 2.04 times as much as atrazine in leaves in single and co-contaminated atrazine treatments. In the solution, atrazine removal became stable after 7 days. Cu²⁺ inhibited the total accumulation of atrazine in plants by 12.5 %. Copper-induced biological phenol-like components in solution decreased the total atrazine accumulation in A. tatatinowii.