Occurrence and risk assessment of heavy metals in an urban river supplied by reclaimed wastewater

Abstract

Heavy metals in reclaimed water are a global problem that leads to ecological risks for the replenishment water body. This study investigated concentrations and ecological risks posed by heavy metals in SH River, Beijing, which is supplied by reclaimed water. Results showed that Cr was not detected in the sample, Cd and Pb exceeded threshold values according to regulations by 1.19% and 25.00%, respectively. The characterization of temporal and spatial of heavy metals was studied. The potential ecological risks posed by heavy metals in SH River were found to be low and safe. The risk decreased in the order Pb > Cu > Zn > Ni > Cd > As by comprehensive index assessment; this changed to Pb > Cd > As > Ni > Cu > Zn according to potential ecological risk assessment. Pb posed the greatest ecological risks and was identified as most contaminated metal. According to discussion of sampling sites and water quality, it was proposed that reclaimed water and exogenous discharges were the main sources of the heavy metals identified. This should be considered when developing catchment management strategies for heavy metals elimination and protection of the aquatic environment. If a higher level of ecological risk management is required, Pb, Cd, and Cu should be considered first and should be removed in situ through ecological remediation methods. Practitioner points Reclaimed water and exogenous discharges were the main sources of the heavy metals identified. The potential ecological risks posed by heavy metals in SH River were found to be low and safe. The risk decreased in the order Pb > Cu > Zn > Ni > Cd > As by comprehensive index assessment. Potential ecological risk assessment showed Pb > Cd > As > Ni > Cu > Zn. Pb posed the greatest ecological risks and was identified as most contaminated metal.

Atmospheric Deposition of Particulate Matter and Micropollutants as a Major Mass Transport Route to Surface Water in Winter: Measurement and Modeling in Beijing in 2014 and 2021

“…Cu, Pb, and Ni are all related to traffic pollution and Hg, Co, and Cr are all related to coal combustion . The areas around Beijing (e.g., Hebei) have a large amount of domestic and industrial emissions from coal burning, boilers, and steel production, and emissions have further increased due to heating in winter and the continued operation of heavy industry. ,,,− Compared with the concentration of the sewage treatment plant and Beijing SH River (Table S22), we can also see that the concentration of Cu, Pb, Ni, and Cr in the surface water of the sampling site may be higher than the environmental background concentration, indicating that these heavy metals were probably derived from traffic pollution and coal burning. The average concentrations of Fe, Sb, As, and Mn in the second principal component were similar to those in the effluent of the sewage treatment plant and Beijing SH River (Table S22), confirming that the second principal component mainly came from sewage treatment plant.…”

In situ, high-resolution evidence for the release of heavy metals from lake sediments during ice-covered and free periods

“…Moreover, under lower redox potential conditions beneath the ice cover, the reduction of Fe/Mn oxides in the sediment would occur, leading to the release of adsorbed Cd, Pb, and Zn back into the overlying water (Huo et al, 2015;Zhang et al, 2020b). Furthermore, the notable rise in arsenic, lead, and manganese concentrations in surface waters from January to May could be linked to increased agricultural runoff, as the region's intensified farming practices involve fertilizers and pesticides known to contain specific heavy metals like arsenic and lead (Tang et al, 2010;Deng et al, 2016;Zhang R. et al, 2020;Zhang J. et al, 2022).…”

Assessment and Comprehensive Evaluation of Large-Scale Reclaimed Water Reuse for Urban River Restoration and Water Resource Management: A Case Study in China

“…Despite the development and progress made, several challenges and limitations have been identified in the research on reclaimed water reuse in urban rivers. Public perception and acceptance remain significant hurdles, as there are concerns about the safety and aesthetic aspects of using reclaimed water for river replenishment [18,[22][23][24][25]. Water quality variability and uncertainty pose additional challenges.…”