Estimation of Fluxes of Lead, Cadmium, and Elemental Carbon from the Atmosphere to the Coastal Zone of the Southeastern Part of the Baltic Sea

Abstract

The fluxes of lead, cadmium, and elemental carbon from the atmosphere to the coastal zone of the southeastern part of the Baltic Sea were assessed. The highest values of lead (11 341 μg m⁻² month⁻¹) and cadmium (682 μg m⁻² month⁻¹) fluxes were revealed in the summer season, while those of elemental carbon (0.69 mg m⁻² day⁻¹) were noted in spring. According to field measurements over a 15-year observation period (2008–2022), the annual average fluxes into the coastal zone of the southeastern part of the Baltic Sea were 4.1 kg km^–2 year⁻¹ for lead and 0.02 kg km⁻² year⁻¹ for cadmium. The calculated annual average fluxes amounted to 3.8 kg km⁻² year⁻¹ for lead and 0.03 kg km⁻² year⁻¹ for cadmium over the region under study. Cadmium emission was inconsiderable in the region. The annual average lead flux, according to field data, was 9% higher than its emission values calculated with the EMEP database. The lead fluxes obtained from both field data and calculations significantly exceed its background level of 1.86 kg km⁻² year⁻¹. In rainfall over the spring-summer periods of 2019–2022, the average concentration of elemental carbon was more than two time lower than the content of organic carbon. The flux of elemental carbon was characterized by seasonal and interannual variability. The increase in the content of elemental carbon in atmospheric precipitation over the spring season was due to anthropogenic load from local sources, namely, spring grass burning in the region. The ecosystems of the coastal zone of the southeastern part of the Baltic Sea experience the greatest anthropogenic load through the atmosphere over spring and summer with an increase in the flux of elemental carbon, lead, and cadmium.