Evaluation of contamination characteristics and source apportionment of heavy metals in river sediments and their risk to human health: A case study in the Heilongjiang Basin, China

• Geochemical speciation and sources of heavy metals (Zn, Cr, Pb, Cu, As, Cd, Hg) were studied. • Cd and Hg were the most polluted heavy metals in surface sediments. • Children exhibited significant Pb-induced carcinogenic risk. • APCS-MLR and PMF models was utilized to quantitatively analyze the sources of heavy metals. The concentration of zinc (Zn), chromium (Cr), lead (Pb), copper (Cu), arsenic (As), cadmium (Cd) and mercury (Hg) in surface sediments of the Heilongjiang River, China, was determined to evaluate the contamination characteristics and source apportionment of heavy metals as well as their potential risk to ecology and human health. This result founded that the order of heavy metals concentrations was Zn(62.51±17.38)>Cr(42.45±12.08)>Pb(28.16±5.91)>Cu(11.25±8.86)>As(7.20±3.70)>Cd(0.13±0.05)>Hg(0.03±0.02). Comprehensive assessments were used to identify the ecological risks and biological toxic effects caused by heavy metals. Noncarcinogenic risks were not significant in both children and adults. The total carcinogenic risk (TLCR) posed to children in the research region needed more attention. Moreover, Pb-related TLCR apportionment was higher compared with other heavy metals. Based on the correlation analysis, the APCS-MLR and PMF models was utilized to quantitatively analyze the sources of heavy metals. These achievements furnished crucial evidence for safeguarding the water resources of the Heilongjiang River and served as an invaluable reference in ensuring ecological safety and preventing pollution across other river systems.