Heavy metal pollution and toxicity assessment in a small urban river: analysis of the Bogdanka river catchment (Poznań, Poland)

Urbanization and the increasing share of impervious surfaces promote heavy metal (HM) inputs to small urban rivers, mainly via surface runoff and stormwater drainage systems. The aim of the research was to identify HM (Cd, Cr, Cu, Ni, Pb, Zn) pollution in water and bottom sediments within the Bogdanka River catchment in Poznań. Samples from 28 sites were collected in March and June 2024 and were analysed using inductively coupled plasma triple quadrupole mass spectrometry (ICP-QQQ-MS). Data evaluation included selected pollution and toxicity indices and principal component analysis (PCA). The results revealed contamination of bottom sediments in the lower river course, attributed to stormwater drainage, which represents the main HM source in the catchment. Toxicity indices showed that HMs in water and bottom sediments do not pose significant toxicological risk. Additionally, PCA suggests that organic matter content and sediment pHKCl are important factors influencing HM accumulation in sediments.