Abstract

Contaminants enter plants through three major pathways, by the root uptake and subsequent translocation into various plant parts through the transpiration process, by vapour uptake from the surrounding atmosphere and by the deposition of contaminated soils and dusts on plant cuticles and subsequent contaminant diffusion through plant surfaces. The uptake and immobilization of phenanthrene by the radical system of Cyperus hermaphroditus was studied by employing a hydroponic system. The plants were exposed to 40, 80, and 120 mg/L of this pollutant for 3 and 12 days. Phenanthrene was extracted and quantified by U.V. spectroscopy and HPLC analysis. The uptake and sorption of phenanthrene in these species increased with plant age and with the exposition time to the contaminant. Due to the greater total root mass with a more surface area as well as the enhanced affinity of the roots for the pollutant, the radical system of C. hermaphroditus may thus provide a surface for phenanthrene biosorption. Consequently the retention of contaminants by plant roots could be an important control in stabilizing otherwise immobile organic compounds.

Key words: Hydroponic culture, phenanthrene, radical system, uptake, bioconcentration factor.