ATMOSPHERIC BULK DEPOSITION OF CARCINOGENIC PAHS IN A RURAL AREA IN SOUTHERN ITALY

The bulk depositions of seven carcinogenic PAHs were investigated by collecting two monthly samples at seven sites. Deposition rates of individual PAHs ranged 2–89 ng/m²/d (BaP, 2–7 ng/m²/d), in agreement with the few available rates previously measured at background European sites. On six days, air samples were also collected at three sites and resulted in mean particle-bound BaP ranging 0.01–0.04 ng/m³. The ratios between the concentrations of each PAH and BaP in the deposition samples were significantly higher than those in the air samples. To investigate if an on-sampler BaP degradation during a 1-month sampling period could generate a measurable artefact, a test was carried out by two co-located samplers collecting, respectively, one continuous 5-week sample and five weekly samples. No difference in PAH profiles was found among the samples collected by the two samplers. The occurrence of PAH profiles different from those commonly found in air may affect the validity of the BaP-marker approach in risk assessment for deposition samples.

Keywords:

• background sites
• BaP
• polycyclic aromatic hydrocarbons
• PAH profile

An acknowledgement is due to Silvia De Luca and Anna Rita Fulgenzi for extracting the samples collected in Melfi. This study was carried out within the framework of investigations co-financed by the Regional Agency for Environmental Protection of the Basilicata Region (ARPAB), contract ISS no. F-54.

Notes

^a Sites nos. 1–3: outside the industrial area; no. 4: residential; nos. 5–7: at the edge of the industrial area. See the text for the site description

^b The three isomers BbFA, BjFA and BkFA were determined cumulatively

^a Averages over six sampling days

^b As per Table 1

^a As per Table 1

^b The three sites where air samples too were collected

^c Inverse values of profiles. Mean of the sites nos. 3, 6 and 7 (see footnote b)

^a Two co-located samplers collecting, respectively, one sample per week and one sample throughout the whole 5-week period

^b Average of three samples collected during deposition sampling (see text)

^c The given values are the measured concentrations: they are overestimated due to the relatively high blank signals (roughly contributing half to the sample signals); half concentrations were assumed in the calculation of the mean