A radiological survey and the impact of the elevated concentrations of 210Pb and 210Po released from the iron- and steel-making plant ILVA Taranto (Italy) on the environment and the public

A radiological survey on the iron- and steel-making plant ILVA Taranto (Italy) was mainly focused on contamination source-term investigation and exposure impact evaluation of the volatile radionuclides 210Po and 210Pb. The activity concentrations of 210Po and 210Pb in the raw materials, dust particles, surficial soils and atmospheric particulate samples collected in the area of ILVA Taranto were determined. The results showed that the activity concentrations in the raw materials were in the range of 3.46–17.9 Bq kg−1 for 210Po and 3.50–16.8 Bq kg−1 for 210Pb, which could create maximum annual inventories of 2.64 × 1011 Bq of 210Po and 2.71 × 1011 Bq of 210Pb if a total quantity of 22 Mt per year raw materials was consumed in the plant. The activity concentrations in dust particles emitted from the chimney of the ILVA Taranto were in the range of 5.91–85.6 kBq kg−1 for 210Po and 5.44–34.6 kBq kg−1 for 210Pb, releasing more 210Po than 210Pb. The activity concentrations in surficial soils were in the range of 49.3–140 Bq kg−1 for 210Po and 51.6–150 Bq kg−1 for 210Pb, a variation of the activity concentrations being observable with distance. The activity concentrations in atmospheric particulate were in the range of 43.1–564 μBq m−3 for 210Po and 618–1099 μBq m−3 for 210Pb, and it was observed that the mass specific activity concentrations of 210Po and 210Pb in the atmospheric particulate are one to three orders of magnitude higher than that found in the top soil. After deduction of the background contribution, about 27.2 μSv per year of the estimated committed effective dose at mean and 49.2 μSv per year at maximum could be attributed to 210Po and 210Pb emitted from the chimney of the ILVA Taranto and inhaled by the public in the form of atmospheric particulate, of which about 63.5–69.0% was the contribution of 210Pb. No specific interventions should be required, as far as only inhalation of 210Po and 210Pb are concerned.