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 treated wood structures. Aquatic macrophytes are important components of aquatic systems, which may be adversely affected by creosote contamination. Several chemicals that are constituents of creosote are known to affect cell membranes in various organisms. Therefore, the effect of creosote on the membrane permeability of the aquatic macrophyte Myriophyllum spicatum was investigated. Apical meristems from axenic Myriophyllum plants were exposed for 4 days to 8 creosote treatments (ranging from 0.1 to 92 mg creosote/l) plus controls. Following the exposure, the ion leakage from the cellular membranes was determined via conductivity measurements. The concentration of 15 polycyclic aromatic hydrocarbons (PAHs) in the growth medium and in the plant tissue was also determined. A significant increase in ion leakage was observed at all creosote concentrations, even those in which no biological effects were observed on plant growth. However, saturation of the growth medium with PAHs was observed, thus indicating that nominal creosote concentrations may over-estimate the actual exposure.