Studies on the effect of heavy metals (Cd, Pb, Cu, Mn, Zn and Fe) upon the growth, productivity and quality of lavender (Lavandula angustifolia Mill.) production

Studies have been conducted on the effect of the aerosol and soil heavy metal pollution upon the growth, development and quality of Lavandula angustifolia Mill. in field experiments, during the period of 1989-1992. Cultivars Hemus and Druzhba, which were used as experimental material, were grown in three different environments. The first was at a distance of 400 m from Non-Ferrous Metals Combine (NFMC near Plovdiv), on heavily polluted soils; the second was at 3 km from NFMC, on less polluted soils, and the third control plot was at 9 km from NFMC, in the experimental field of Agricultural University in Plovdiv. At different growth stages of the lavender plants, fresh herbage yield, height, amount of branching, essential oil content, and GC analysis of the oils were determined. In addition, heavy metal content in the soils, plant roots, stems, leaves, racemes, essential oils and the wastes from the distillation were also determined. It was found that soil and air heavy metal pollution did not affect the occurrence and duration of the different growth stages of lavender, the amount of branching, the essential oil content, the yield of fresh inflorescences and oil composition. Depending on the rate of soil and air pollution, inflorescences accumulated different amounts of heavy metals. In spite of the great amounts of heavy metal accumulated by the inflorescence, the oil was not contaminated. A positive correlation between metal concentration in the inflorescence and that found in the oils for Cu was observed. Heavy metal concentration in plant parts was observed in the following order for each metal: Cd: leaves > roots = inflorescences = stems; Pb: stems > leaves = inflorescences > roots; Cu: roots > leaves = inflorescences = stems; Mn: roots > leaves = inflorescences > stems; Zn: leaves = stems > inflorescences > roots; and Fe: roots > leaves > stems > inflorescences. The results obtained could be used as a model for other similar crops grown in other regions in which a similar rate of industrial pollution can be found. It was concluded that the lavender cvs Druzhba and Hemus could be successfully grown in highly heavy metal polluted areas without any risk of essential oil contamination.