Using a novel petroselinic Acid embedded cellulose acetate membrane to mimic plant partitioning and in vivo uptake of polycyclic aromatic hydrocarbons.
Xiuying Li, Yanhong Zhu, Tong Wu, Shuzhen Zhang, Peter Christie
A new type of composite membrane is introduced to mimic plant uptake of hydrophobic organic contaminants (HOCs). Petroselinic acid (cis-6-octadecenoic acid), the major component of plant lipids, was embedded in the matrix of cellulose acetate polymer to form the petroselinic acid embedded cellulose acetate membrane (PECAM). Accumulation of the polycyclic aromatic hydrocarbons (PAHs) naphthalene (Nap), phenanthrene (Phe), pyrene (Pyr), and benz(a)pyrene (Bap) by PECAM was compared with their uptake by plants. The accumulation of Nap, Phe, Pyr, and Bap by PECAM reached equilibrium in 24, 48, 144, and 192 h, respectively. The petroselinic acid-water partition coefficients (log K(pw), 3.37, 4.90, 5.24, and 6.28 for Nap, Phe, Pyr, and Bap, respectively) were positively correlated with the hydrophobicity of the compounds (R(2) = 0.995) and were almost the same as the lipid-normalized root partition coefficients (log K(lip)) for the corresponding compounds. Their relationship can be expressed as log K(pw) = 0.98 log K(lip). The normalized plant uptake coefficients (log K(u)) obtained by in vivo experiments with a range of plant species (2.92, 4.43, 5.06, and 6.13 on average for Nap, Phe, Pyr, and Bap, respectively) were slightly lower than those of the log K(pw) values for the corresponding compounds, presumably due to their acropetal translocation and biodegradation inside plants. This work suggests that PECAMs can well mimic plant partitioning and in vivo uptake of PAHs and may have good potential as a nonliving accumulator to mimic plant uptake of PAHs and perhaps other HOCs.
