Contamination of Scots pine forests with polycyclic aromatic hydrocarbons on the territory of industrial city of Siberia, Russia

Abstract

Anthropogenic contamination with polycyclic aromatic hydrocarbons (PAH) coming from a powerful aluminum smelter has been estimated by the accumulation of these substances (17 substances: phenanthrene, fluoranthene, pyrene, chrysene, acenaphthylene, acenaphthene, anthracene, fluorene, benz[а]anthracene, benz[b]fluoranthene, benz[k]fluoranthene, benz[а]pyrene, benz[е]pyrene, perylene, indeno[1,2,3-c,d]pyrene, benz[g,h,i]perylene, dibenz[a,h]anthracene) in needles of Scots pine (Pinus sylvestris L.) in the residential areas of Bratsk, East Siberia, Russia. It has been found that the total PAH amount reaches the maximum values (982 ng/g) in the needles of trees growing in a residential zone, remote from the smelter up to 10 km (Central Urban District), where more than half of the city's population lives. On the territory remote up to 25 km (Padunsky District), PAH needle levels decline, but are still 14.5–17.5 times higher than the background ones and at a distance of 45 km (Pravoberezhny District), they still exceed background levels (30 ng/g) by 4.7–8.1 times. Qualitative analysis of PAH showed the prevalence (up to 90% of the total amount) of 3–4 ring PAHs in pine needles on the entire studied territory. PAH concentrations increase when approaching the smelter with the highest values in the Central City District. Within the urban area, the content of PAHs with 5–6 rings (benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene (B[a]P), benz[a]anthracene, dibenz[a,h]anthracene, indeno[1,2,3-c,d]pyrene, benzo[g,h,i]perylene) is also significantly increased. In the Central District, needle concentration of B[a]P, which is a class 1 carcinogen, exceeds the background one by 22 times, the Padunsky District—by 7 times, and the Pravoberezhny District—by 3 times. In the territories of the Central Districts, needle level of perylene, which is a marker of territory pollution by aluminum smelter emissions, is 18 times, the Padunsky District—by 10 times, Pravoberezhny District—by 2.5–3 times higher than in the background, where the perylene level is below the detection limit (< 0.2 ng/g).