Pentachlorophenol: Uptake/elimination kinetics and metabolism in an aquatic plant, Eichhornia Crassipes

Abstract

AbstractEichhornia crassipes [(Mart) Solms], an aquatic plant widely used for the treatment of wastewaters, was used to study uptake/elimination kinetics and metabolism of pentachlorophenol (PCP). PCP is a well‐known industrial by‐product and a major pollutant of the aquatic environment. The initial phase of PCP uptake by the plant was rapid and reached a nearly steady state between 24 and 48 h of exposure to PCP. The major by‐products of PCP metabolism in Eichhornia crassipes were identified as ortho‐ and para‐ substituted chlorohydroxyphenols (chlorocatechols and ‐hydroquinones), ‐anisoles, and ‐veratroles. Partially dechlorinated products of PCP were also detected. A major portion of the absorbed PCP and metabolites was found in bound/conjugated form. The responses of the enzyme systems involved in the xenobiotic metabolism and antioxidative system were also studied following PCP exposure. A significant increase was observed in the activity of glutathione S‐transferase (GST), a major conjugating enzyme, and in the activities of superoxide dismutase and ascorbate peroxidase (Halliwell‐Asada pathway enzymes) of PCP exposed plants. Such responses of plant enzymes may be implemented as useful markers of aquatic pollution. The result related to the uptake and metabolism of PCP obtained from the present study suggests a crucial role of aquatic plants in determining the fate of environmental chemicals.