Effect of redox gradients on Cu and Zn concentrations in water of Blanakan River, West Java

Metal concentrations in water threat adjacent ecosystems due to the potential of metal mobilization and the subsequent uptake into water. Here, contents of heavy metals Cu and Zn were determined for river waters. We used factorial analysis (FA) to determine the metal contents in relation to environmental factors such as redox potential (Eh), dissolved oxygen (DO), pH, salinity, temperature and turbidity in the Blanakan river. The Zn was ranging from 0.44 to 2.13 mg/L. The FA categorized Zn with salinity and temperature. Meanwhile, the Cu was ranging from 0.02 to 0.05 mg/L. The FA categorized Cu with Eh, turbidity, DO and pH. Such discrepancy in metal concentrations highlighted that redox gradient has more effects on Cu than Zn. Respectively, decrease of Eh from-38 to-41 mV can increase the Cu up to 0.05 mg/L. Correlation of Eh with Cu contents indicating that Cu was influenced by terrestrial inputs. Conversely, correlation of temperature and salinity with Zn contents indicating that Zn was influenced by aquatic inputs.