Indicators of the Pollution of Surface Waters of the Lake Baikal Watershed by Polycyclic Aromatic Hydrocarbons

The content of polycyclic aromatic hydrocarbons (PAH), organic carbon (Corg), and mineral nitrogen (Nmin) in waters of Lake Baikal and its tributaries were analyzed. On the basis of these data, the indicators of the water composition, for Baikal Lake and its tributaries, were worked up for the first time. These indicators—the anthropogenic impact on the ecosystem (PAH/Corg) and the indicator of the capacity of the ecosystem to neutralize pollution (Nmin/Corg)—show a link between water pollution and the conditions of the watershed basin. It was established that (PAH/Corg) and (Nmin/Corg) can be used simultaneously as tracers to calculate the tributary input into organic matter of the lake. It was also revealed that Nmin/Corg is inversely proportional to the Corg concentration and directly proportional to N/C in the soil humus. On the basis of the indicators, the watershed areas and water area of the lake were distinguished. The areas are characterized by different levels of the pollution, self-purification capacity, and concentration of carbon in surface waters.