EN
A pot experiment was carried out under controlled conditions to evaluate the combined effect of chemical oxygen demand and heavy metals in synthetic irrigation water on the accumulation of heavy metals in perennial rye grass (Lolium perenne) grown during 30 days on two soils: an acidic sandy soil (pH = 4.0), and the same soil amended with 5% clay (pH = 6.7). The dry matter yield of rye grass decreased and heavy metal concentrations in plant tissue increased with heavy metal concentration in the irrigation water. A higher COD concentration in the irrigation water also resulted in an overall decrease of dry matter yield and higher metal contents. The addition of 5% clay to the acidic soil reduced these effects. However, the clay content of the soil was by far the most important factor in controlling plant growth and metal uptake.