Variation Feature, Pollution Risk Assessment, and Source Analysis of Heavy Metals in Lanzhou City, Northwestern China

Lanzhou is located in the northwest of China and famous for its petrochemical heavy industries China. The city has suffered long-term pollution metals recent years. Significant efforts, such as tax subsidies new energy vehicles treating solid waste, have been launched by municipal government to address since 2010. What current status metal Lanzhou? In this study, concentrations 12 (V, Cr, Mn, Co, Ni, Cu, Zn, As, Mo, Cd, Sb, Pb) were tested from 20 sediment samples. V, Cr are predominant metals, with mean 534.65, 65.85, 56.29, 36.05 mg/kg; Pb, As moderate amounts, 25.2, 21.5, 16.7, 9.87, 4.86 Mo Cd lowest 0.54 0.15 mg/kg. A low ecological risk confirmed two indices, Hakanson potential index ( R I ) geoaccumulation id="M2"> geo ). id="M3"> lower id="M4"> E i r values (<40) id="M5"> (<150), which range 18.11 37.95, an average value 25.61. Mn classified uncontaminated environment (level 0) a moderately heavily contaminated 2-level 3) id="M6"> values. Seven (Pb, Ni) relatively amount 5 cities changing trends firstly increase then decrease gradually 2005 2022. time turning point concentration shrinking occurred approximately 2014, response increased efforts addressing Source analysis Pearson’s correlation principal component revealed that accumulation was caused enrichment MnO2 oxidic condition; accumulations Pb influenced natural sources human activities (vehicle exhaust industrial pollution), respectively.