Influence of multiwalled carbon nanotubes and sodium dodecyl benzene sulfonate on bioaccumulation and translocation of pyrene and 1-methylpyrene in maize (Zea mays) seedlings

Influence of multiwalled carbon nanotubes with outer diameters > 50 nm (MW) and a surfactant sodium dodecyl benzene sulfonate (SDBS) on bioaccumulation and translocation of pyrene and 1-methylpyrene (1-CH3-pyrene) in maize seedlings in single-(F1) and bi-(F2) compound systems was investigated. Pyrene concentration in shoots was detected in all treatments in F1 and F2, ranging in 10.43–60.28 ng/g and 21.46–40.21 ng/g, respectively, and its translocation factors (TFs) ranged in 0.12–0.19 and 0.07–0.16. However, no 1-CH3-pyrene in shoots was detected from F1 and F2, indicating almost 100% suppression on its translocation from roots to shoots. SDBS at 100 mg/kg significantly enhanced pyrene bioaccumulation in roots and shoots by 43.5% and 77.4% in F1, and 21.7% in roots in F2, while showed insignificant effect on shoot concentration in F2. In contrast, SDBS at 100 mg/kg exerted no significant effect on root 1-CH3-pyrene concentration in F1 and F2. With increasing amendment level of MW from 50 to 3000 mg/kg, both pyrene and 1-CH3-pyrene concentrations in roots and shoots sharply decreased, indicating an increasing suppression on their bioaccumulation and translocation in plant. As for 3000 mg/kg MW + 100 mg/kg SDBS, root concentrations of pyrene and 1-CH3-pyrene in F1 were significantly reduced by 53.4% and 100%, while shoot concentration of pyrene was not affected, generally consistent with the trend of the corresponding bioaccumulation factors (BCFroot) and TFs. As for F2 with the same treatment, root 1-CH3-pyrene concentration declined by 68.6%, whereas pyrene bioaccumulation in roots and shoots was insignificantly affected, which were also in agreement with their BCFroot and TFs. Results of this work highlight the combined impacts of soil amendment with carbon nanotubes and surfactant on bioaccumulation and translocation of pyrene and 1-CH3-pyrene in maize seedlings in multi-pollutant exposure systems, which is important for soil pollution control and food safety assessment.