Assessment of heavy metals in soil, oilseed rape (Brassica napus L.) and honey

The aim of this study was to determine the heavy metals concentrations in soil, inflorescences of Brassica napus L. and rapeseed honey sampled from some regions of north-eastern Bulgaria. Thirteen locations were selected for experimental studies. The soils, plants and honey samples were taken from conventional beekeeping areas away from major industrial pollutants. The median amounts of elements in the soil samples (mg/kg dry weight (DW)) are 1.1246 for Fe-(s), 0.7048 for Al-(s), 0.5636 for Pb-(s), 0.1658 for Cu-(s) and 0.0148 for Zn-(s). The median amounts of heavy metals measured in the inflorescences of Brassica napus (mg/kg DW) are 5.5430 for Fe-(p), 2.9095 for Zn-(p), 1.3225 for Pb-(p), 0.2593 for Cu-(p) and 0.2105 for Al-(p). The median heavy metals concentrations in tested honey (mg/kg DW) are 1.0026 for Fe-(h), 0.1849 for Al-(h), 0.1832 for Pb-(h), 0.1250 for Zn-(h), and 0.0702 for Cu-(h). The relationship between the heavy metal in soil, plants and honey was investigated using Spearman's rank correlation coefficient. Significant differences in the concentrations of Fe(s), Al-(s) and Pb-(s) in soils, Fe-(p) and Zn-(p) in the plant samples and Fe-(h) in honey samples from the different locations were found. The heavy metal content tested in honey did not pose a risk to human health.