Metals in pine needles: characterisation of bio-indicators depending on species

Air pollution can be studied by appropriate bio-indicators, such as pine needles due to their waxy surface. Metal uptake and accumulation is determined on growing area, but also on the respective species. Scope of the study was to analyse needles of Pinus densiflora Siebold et Zucc., Pinus nigra Arnold, Pinus sylvestris L., and Pinus thunbergiana Franco for metals and metalloids, namely aluminium, arsenic, boron, barium, calcium, cadmium, cobalt, copper, chromium, iron, potassium, lithium, magnesium, manganese, molybdenum, sodium, nickel, lead, selenium, strontium, and zinc. Quantitation of the analytes was performed using inductively coupled plasma atomic emission spectrometry and inductively coupled plasma sector field mass spectrometry after acidic microwave-assisted digestion. The obtained data were checked for statistically significant differences. The metal levels differ between the various species, but no general tendency was found for all metals. Since the environmental conditions were the same for all sampled trees, the differences in metal accumulation are supposed to be linked to species of pine tree. The diverse accumulation behaviour can be used for treating polluted soil.