Pentachlorophenol metabolism plant

Roy S, O Hanninen (1994) Pentachlorophenol uptake/elimination kinetics and metabolism in an aquatic plant Eichhornia crassipes. Environ Toxicol Chem 13 763-773. 

Pentachlorophenol in terrestrial ecosystems clears rapidly (Haque et al. 1988). In one case, a terrestrial ecosystem was given a single surface application of radiolabeled PCP equivalent to 5 kg sodium pentachlorophenate/ha. PCP residues on foliage decreased rapidly, with 50% metabolized within 15 days. After 131 days (autumn), most of the remaining PCP was in the topsoil and plant litter. After 222 days (winter), 39% of the radiocarbon remained. There was little bioconcentration in the resident fauna, due to rapid metabolism and excretion (Haque et al. 1988). 

Pentachlorophenol is metabolized by the aquatic plant Eichhornia crassipes to a number of metabolites including di-, tri-, and tetra-chlorocatechol, 2,3,5-tri- and tetrachlorohydroquinone, pentachlo-roanisole, and tetrachloroveratrole (Roy and Hanninen 1994). The phenolic compounds should be compared with those produced during the photochemical (see Figure 4.4) and the initial stages in the microbiological metabolism of pentachlorophenol (Chapter 6, Section 6.5.1.2), followed by O-methylation (Section 6.11.4). 

Although the rate of metabolism of a chemical is dependent upon the plant system in which it is placed, a standardized screen with certain plant species would provide a basis for initial comparison, which could be modified as more specific results were obtained. Proponents of a standardized method for comparison of xenobiotic metabolism in plant cell cultures have developed a flow diagram for such a screening procedure using soybean and wheat cell suspensions (Figure 6) (59). Using this procedure, the authors compared metabolism of di-(2 ethylhexyl)-phthalate. (DEEP), pentachlorophenol (PCP). 

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