Identifying and Characterizing Critical Source Areas of Organic and Inorganic Pollutants in Urban Agglomeration in Lake Baikal Watershed

Abstract

Critical source areas (CSAs) are the areas prone to generating runoff and are characterized by a high level of soil pollution. CSAs may accumulate and release soil pollutants emitted by primary emission sources (industrial and municipal enterprises) into the surface water during storm events. The aim of this study was to identify CSAs and their pollution sources and to assess the level of soil pollution in CSAs with polycyclic aromatic hydrocarbons (PAH) and trace metals (TM). CSAs were identified using a geospatial data model (GIS), and primary emission sources were identified using a positive matrix factorization (PMF) model. It was found that the soils of CSAs were characterized by higher pollution levels than soils outside the CSAs. Pollution levels were highly variable among the identified CSAs due to the different capacities of the plants located in those areas. Due to high variability of TM concentrations in preindustrial soils, the pollution level of PAHs and the pollution level of TMs in CSA soils did not correlate with each other. The PAH composition of bottom sediments was different from that of soils, whereas the TM compositions of the soils and bottom sediments were similar. It was proved that the main sources of PAHs and TMs in CSA soils were traffic emissions and central heating boilers.

Composition, Concentration and Origin of Polycyclic Aromatic Hydrocarbons in Waters and Bottom Sediments of Lake Baikal and Its Tributaries

“…The PAH composition of this factor was similar to that of coal combustion (Figure 15a) obtained for water using the PMF model. The profile of PCA-derived Factor 1 was also similar to that of coal and wood combustion identified using the data on the PAH composition of soil sampled near the coal-fired thermal power plant in Ulan-Ude city [36]. Taking everything mentioned above into account, Factor 1 was identified as coal combustion.…”

“…Therefore, it was assumed that Factor 1 represented coal combustion, Factor 1 (Figure 15a) was characterized by the highest concentration of IcdP and BghiP among all factors. Abnormally high concentrations of IcdP and BghiP had been previously found in the soil influenced by the emission from thermal power stations in Ulan-Ude city [36]. Therefore, it was assumed that Factor 1 represented coal combustion, although its PAH composition was similar to that of a wood-burning stove (Figure 12b).…”

“…The existence of the fractionation phenomenon is indirectly confirmed by the similarity of PAH compositions of inland waters around the world. In fairness, it should be noted that the PAH compositions of Factors 4 and 5 are quite similar to that of products of gasoline combustion [36,69].…”

“…Identified factors may conditionally be divided into three groups: (1) factors characterized by a high abundance of five-and six-ring PAHs (Figure 15a Factor 1 (Figure 15a) was characterized by the highest concentration of IcdP and BghiP among all factors. Abnormally high concentrations of IcdP and BghiP had been previously found in the soil influenced by the emission from thermal power stations in Ulan-Ude city [36]. Therefore, it was assumed that Factor 1 represented coal combustion, Factor 1 (Figure 15a) was characterized by the highest concentration of IcdP and BghiP among all factors.…”

“…The obtained idea that the PAH source closest to the water body is the primary contributor of PAHs to its water and sediments reduced the interest in studies concerned with source apportionment of PAHs. The results of such studies began to appear in the scientific literature in the past six or seven years [33][34][35][36][37]. The lack of data on the PAH composition of surface water until the middle of the 2000s was probably conditioned by difficulties in measuring low PAH concentrations.…”