The heavy metal deposition in snow: case study of Jelgava city

Majority of world inhabitants are living in cities as well as many inhabitants in Latvia choose to move to cities to look for wellfare. Living in a city with a high density of buildings, cars, and factories, the risk of air pollution increases. Air pollution from the transport, industry, and energy sectors affect the health of the urban population. In cities, air is often contaminated with dust containing various chemical elements, including heavy metals, which, even in low concentrations, can be hazardous to human health. The aim of the study is to determine the distribution of heavy metals in the urban air as well as the relation of heavy metal concentration to anthropogenic point and nonpoint pollution sources. In winter 2019, 183 snow samples were collected in 61 different locations in the city of Jelgava to determine concentrations of various heavy metals in the city and to cover all possible urban areas: residential, industrial, high-rise, and more. In study, distribution of copper (Cu), nickel (Ni), lead (Pb), manganese (Mn), and zinc (Zn) are analyzed in the urban environment. ICP-OES spectrometer "iCAP 7000" is used for the analysis of snow samples. In the first analysis step, samples are acidified with 1% HNO3. In the second step, the sample is hold for three days. In the third step, the sample is filtered through a paper filter and further analyzed with the "iCAP 7000". The spatial interpolation and the mapping methods were performed using ArcGIS 10.3. The IDW spatial interpolation method build in ArcGIS 10.3 based on relationship between sampling sites and concentrations was used in the study. The spatial results show that Jelgava has inhomogeneous distribution of heavy metals in the air, where the highest concentrations were found near the source of anthropogenic pollution. The highest observed concentrations of heavy metals are: Cu 12.5 (μg/l), Ni 4.4 (μg/l), Pb 72.3 (μg/l), Mn 73.0 (μg/l), Zn 204.5 (μg/l).