Zinc, lead, cadmium and copper concentrations of meadow plants along the M3 motorway

Abstract

The toxic heavy metal concentrations were investigated in plants in a meadow located 51 kilometres from Budapest along the M3 motorway. The field is regularly harvested, and the hay is used as fodder. The area under investigation is situated directly alongside the protecting fence of the motorway. The soil of the area is classified as chernozem brown forest soil. In 2000 approximately 22,860 cars per month travelled on the motorway. The plant samples were taken at a distance of 5, 10, 25, 50 and 100 metres from the motorway. At each distance 10 samples were collected. After digestion with hydrogen peroxide and nitric acid the zinc, lead, cadmium and copper contents of the samples were analysed using an ICP spectrophotometer. After analysing the data it was established that for each of the heavy metals the concentration of metal in the plant samples decreased as the distance from the motorway grew. The measured zinc, cadmium and copper concentrations were similar to those reported by other authors (on average 44.9, 0.276 and 5.25 mg kg-1), while the values of the lead concentration were lower than those published previously (on average 2.93 mg kg-1). This may have been due to the widespread use of lead-free fuel.