In the present work, a study has been carried out on the contamination of heavy metals in urban dust deposited on the roads of the city of Cartagena (Spain), in order to know the content of metals such as Ni, Zn, Pb, Cd, Cr and Cu. Likewise, the possible relationship of the concentration of heavy metals with the color of the sample, level of magnetism and traffic density was studied. Contamination was evaluated using several indices such as contamination factor (CF), enrichment factor (EF), geoacumulation index (Igeo), pollutant load index (PLI) and ecological risk index (RI). A total of 88 samples were taken in the urban area of Cartagena, and the metals were determined by acid digestion and measured by inductively coupled plasma mass spectrometry. The concentration of heavy metals in urban dust from Cartagena was Zn (672 mg/kg) > Cu (248.9 mg/kg) > Pb (227 mg/kg) > Cr (82.7 mg/kg) > Ni (47.7 mg/kg) > Cd (4.1 mg/kg). Contamination levels were high in Pb, Zn, Cd and Cu, according to environmental indices. A correlation was found between magnetism and metal concentration, which was repeated for all metals except Cd. Dark-colored samples contained higher metal concentrations than light-colored samples. Meanwhile, streets with medium and low traffic intensity were found to have higher concentrations of heavy metals. This study's objective was to identify pollution hotspots caused by heavy metals in dust in the urban ecosystem of Cartagena city.

Urban dust samples were taken from the playgrounds of 27 schools located in the urban area of the city of Murcia (S.E. Spain). Their color and degree of magnetism were determined, as well as their heavy metal content (Cd, Cu, Cr, Ni, Pb and Zn) to evaluate contamination by environmental and health indexes. The highest concentration of contaminants is found in dusts of dark color and medium and high magnetism. The concentrations of heavy metals in the dust were, in this order, Zn (453.74 mg kg-1)> Cu (77.44 mg kg-1)> Cr (67.93 mg kg-1)> Pb (55.72 mg kg-1)> Ni (18.56 mg kg-1)> Cd (0.42 mg kg-1). The analysis of the magnetic and non-magnetic fraction indicates that there is a concentration of all heavy metals in the magnetic fraction. According to the geoenvironmental indices used, the ecological risk presented by school playgrounds is moderate. As for the health indices, ingestion was the main route of exposure and entry of dust particles into the body, being the main health risk for adults and children for all metals. The Hazard Index (HI) values for all elements for both adults and children were less than 1, indicating that there is no risk of developing adverse health effects. As for the Cancer Risk (CR), the values of this index indicate that there is no risk. The objective of this study was to evaluate pollution in the playgrounds of schools in the city of Murcia.