A disorder of Norfolk Island pines, Araucaria heterophylla (Salisb.) Franco, has occurred on certain urbanized parts of the coast of New South Wales. Observation and survey work suggested that the disorder was due to excessive foliar uptake of salt, induced by surfactants derived from sewage discharged into the sea. The work described in this paper was part of a programme of studies designed to test this hypothesis.
Glasshouse experiments were carried out to test the effects of distilled water and deep-sea water both with and without added surfactants sprayed onto the foliage of young potted Norfolk Island pines. Whereas the distilled water effects were minimal, some needle and shoot necrosis occurred in all plants sprayed with sea water and this effect was markedly accentuated when surfactant was present. Shoot necrosis was highly significantly correlated with the concentration of sodium and chloride taken up by the foliage, and the foliar salt levels were very similar to those found in deteriorating trees located by the seaside. The results showed that a commonly used surfactant, when sprayed in a sea-water solution onto Norfolk Island pine foliage, caused damage similar to that observed in affected seaside trees.
Exposure of Glass Fiber Reinforced Polymer Composites in Seawater and the Effect on Their Physical Performance
