The effect of creosote on membrane ion leakage in Myriophyllum spicatum L.

Creosote is a complex chemical mixture used as a wood preservative that has the potential to contaminate aquatic systems via spills or leaching from t reated wood structures. Aquatic macrophytes are important components of aqu atic systems, which may be adversely affected by creosote contamination. Se veral chemicals that are constituents of creosote are known to affect cell membranes in various organisms. Therefore, the effect of creosote on the me mbrane permeability of the aquatic macrophyte Myriophyllum spicatum was inv estigated. Apical meristems from axenic Myriophyllum plants were exposed fo r 4 days to 8 creosote treatments (ranging from 0.1 to 92 mg creosote/l) pl us controls. Following the exposure, the ion leakage from the cellular memb ranes was determined via conductivity measurements. The concentration of 15 polycyclic aromatic hydrocarbons (PAHs) in the growth medium and in the pl ant tissue was also determined. A significant increase in ion leakage was o bserved at all creosote concentrations, even those in which no biological e ffects were observed on plant growth. However, saturation of the growth med ium with PAHs was observed, thus indicating that nominal creosote concentra tions may over-estimate the actual exposure. (C) 2000 Elsevier Science B.V. All rights reserved.