Eichhornia crassipes as a Biological Monitor of Heavy Metals in Surface Waters

Abstract

The objective of this study has been to show that chemical analysis of Eichhornia crassipes, technically a simple operation, will serve to indicate river and lake contamination by heavy metals, thus avoiding the relatively laborious and costly process of water sampling and analysis in the monitoring of rivers in tropical and subtropical areas. The great capacity of the floating freshwater vascular plant Eichhornia crassipes, otherwise known as water hyacinth, to absorb substances from the water is well documented. The objective of most of the studies of the plant’s uptake of substances from water has been to demonstrate its potential in waste treatment, either of metal containing wastes (Sutton and Blackburn 1971; Wolverton and McDonald 1975a, b) or for the removal of organic material and nutrients (Boyd 1970; Ramachandan et al. 1971; Wolverton and McKown 1976; Cornwell et al. 1977; Dinges 1978; Lord 1982). Only a small number of studies have been devoted to the possibility of using Eichhornia as a bioaccumulator and thus indicator of contaminant concentration. Amongst these, the work of Chigbo et al. (1982) deals with concentrations higher than those normally encountered even in polluted waters and that of Cooley et al. (1978) treats the subject only incidentally.