Assessment of Chemical Pollution Level in Soils of Petropavlovsk-Kamchatsky

The level of chemical pollution of soils with heavy metals (Co, Mo, Cd, Ba, Cu, Ni, Pb, Cr, Zn, and Mn) and oil products was determined in Petropavlovsk-Kamchatsky in 2023. Application of various ecological and geochemical approaches for a comprehensive assessment of urban environment status revealed different degrees of pollution in the study areas depending on the pollutant and the calculated indices. The maximum content of hazard class I pollutants in soil was 1546 mg/kg for oil products, 3.37 mg/kg for Cd, 248 mg/kg for Pb, and 571 mg/kg for Zn. Anthropogenic sources of their entry were identified. A comprehensive assessment conducted using geochemical (PI, PLI, NPI, Zc) and toxicological (Pt, PERI, MPC, TPC) indices and phytotesting demonstrated that soils of the city are generally slightly polluted. In certain areas associated with motor transport infrastructure and fuel and energy complex enterprises, a high degree of pollution was registered according to integral (NPI, Zc) and concentrations of individual pollutants (Pb, Zn). The maximum soil pollution with heavy metals was noted upon calculating the ecological and geochemical indices; it ranged from 13 (according to the Zc index) to 80% (according to the NPI index) of the total number of monitoring sites. The excess of oil products in soils was insignificant, and 6.6% of soils were defined as oil-contaminated. A comparative analysis of integral indices of the current ecological status of soils in Petropavlovsk-Kamchatsky revealed a number of methodological problems in assessing the pollution level. Taking into account the influence of active volcanism both in the geological past and in the present of the Kamchatka Peninsula, identification of background values for the content of a number of pollutants appears to be an urgent task for objective environmental monitoring of the soil cover in the region.