Wildfires as a Source of PAHs in Surface Waters of Background Areas (Lake Baikal, Russia)

Abstract

Polycyclic aromatic hydrocarbons (PAHs) were detected in different types of PAH-containing samples collected in Lake Baikal during wildfires in the adjacent areas. The set of studied samples included the following: (i) water from the upper layer (5 m); (ii) water from the surface microlayer; (iii) water from the lake tributaries; (iv) water from deep layers (400 m); and (v) aerosol from the near-water layer. Ten PAHs were detected in the water samples: naphthalene, 1-methylnaphthalene, 2-methylnaphthalene acenaphthylene, acenaphthene, fluorene, phenanthrene, fluoranthene, pyrene, and chrysene. The total PAH concentrations (ƩPAHs) were detected in a wide range from 9.3 to 160 ng/L, characterizing by seasonal, intersessional, and spatial variability. In September 2016, the ƩPAH concentration in the southern basin of the lake reached 610 ng/L in the upper water layer due to an increase in fluorene, phenanthrene, fluoranthene, and pyrene in the composition of the PAHs. In June 2019, ƩPAHs in the water from the northern basin of the lake reached 290 ng/L, with the naphthalene and phenanthrene concentrations up to 170 ng/L and 92 ng/L, respectively. The calculation of back trajectories of the atmospheric transport near Lake Baikal, satellite images, and ƩPAH concentrations in the surface water microlayer of 150 to 960 ng/L confirm the impact of wildfires on Lake Baikal, with which the seasonal increase in the ƩPAH concentrations was associated in 2016 and 2019. The toxicity of PAHs detected in the water of the lake in extreme situations was characterized by the total value of the toxic equivalent for PAHs ranging from 0.17 to 0.22 ng/L, and a possible ecological risk of the impact on biota was assessed as moderate.

Polycyclic Aromatic Hydrocarbons in the Atmosphere of the Southern Baikal Region (Russia): Sources and Relationship with Meteorological Conditions

“…The determination limits of PAHs in the filters with aerosol were 0.002-1000 ng/m 3 . The accuracy of the method used was 20%, and reproducibility −25% [3]. The concentrations of PAHs in aerosols are presented in Table 1.…”

“…Sources of PAHs are emissions from thermal power plants, oil refineries, non-ferrous metallurgy, small boiler houses, residential districts with stove heating, and vehicles. In recent years, with the growth of wildfires in the boreal forests of Siberia, the role of this source in the atmosphere has been increasing during spring and summer [3].…”

Molecular Indicators of Sources and Biodegradation of Organic Matter in Sediments of Fluid Discharge Zones of Lake Baikal

“…The third reason for the increase of retene concentration in the background regions of Baikal is aerosol transport of combustion products after the extensive wildfires around the lake's coasts. The eolian input of retene to the northern part of the lake from northern Siberia is up to 0.33 ng/m 3 and is determined predominantly by the combustion of Pinus sylvestris and Larix sibirica, constituting 80% of the forest [116].…”

Sensitivity Operator Framework for Analyzing Heterogeneous Air Quality Monitoring Systems

“…The region is exposed to various anthropogenic and natural factors. For example, it suffers from forest fires of different origins [60][61][62][63]. The industrial activity that develops in the region, mainly near urban settlements, certainly affects the quality of the environment [64][65][66].…”

“…The industrial activity that develops in the region, mainly near urban settlements, certainly affects the quality of the environment [64][65][66]. This unique natural object, BNT, is observed by various means [44,63,[67][68][69][70][71]. Hence, adequate measurement data-fusion is essential to carry out multidisciplinary studies in the region and provide the governing authorities with the necessary data to make decisions in terms of environmental protection to ensure the region's sustainable development.…”