The effect of heavy metals and other toxic elements on plants can be assessed by variousbiotests involving easily determinable parameters such as: length of the underground and aboveground plant parts, biomass, seed germination, photosynthetic pigments content, etc. Simultaneous use increases their sensitivity, offsets their disadvantages and allows obtaining objective results. The aim of this study was to trace the effect of water samples from various points along the Maritsa River (with in the regulation lines of the city of Plovdiv) on selected crops.
During the period of the survey, the Maritsa River waters were polluted with Cd and Pb and of satisfactory quality in relation to the presence of Cu and Zn, since their quantity was under the adopted hygiene standards for Bulgaria. Results of the experiments withcorn and sunflower seeds showed that they had a negative effect on the germination, growth and leaf pigment content ratio of the crops.
The study confirmed that the use of plants as bio-indicators is an effective method for monitoring of contaminated waters. We can point out that the use of the waters of the Maritsa River for irrigation poses a risk to the cultivated crops in the region of Plovdiv. As a result, it is possible to degrade the quality of the crop, which is intended for the feeding of animals and people, however without observing visible signs of metal phytotoxicity.