Complexity of hydrology, sewage and industries in distribution and migration pathways of heavy metals at spatial scale of China's brownfields

Abstract

Hydrologic dynamics, sewage and industries determine the distribution and migration pathways of heavy metals in the natural environments including soils across the urbanized area. In this study, 323 stratified soil samples from a brownfield in Jiangsu Province, China, were collected to assess the heavy metals (Cu, Ni, Pb, Cd, As and Hg) contaminations. Contamination factor (Cfi), Nemerow pollution index (PIN) and enrichment factor (EFi) were evaluated to assess the heavy metal pollution, while sources of pollution were identified in combination with geo‐statistical, correlations and principal components analysis. Moreover, transport of Ni in soil profiles over the next 30 years was simulated using HYDRUS. The vertical distribution revealed that the soil surface (0–10 cm) had the highest concentration of heavy metal contamination. ICP‐MS measurements showed that the soil in the brownfield was enriched with Cu, Ni, Pb, Cd, As and Hg, where Ni was the most severe and prevalent contaminant. The results of source apportionment analysis showed that Ni, Cd, Pb and Cu were mainly derived from building materials and sewage discharge, while As and Hg may come from fossil fuel combustion and agricultural discharges from upstream river catchment. The migration of Ni was largely driven by the combination of hydrological variability including the flow and solute contaminant gradients in soils. Our work highlights the need for a comprehensive understanding of the complexity of hydrology, and sewage discharge in heavy metal dynamics and migration pathways in China's brownfield soil at regional and national scales.

Century-Scale Environmental Evolution of a Typical Subtropical Reservoir in the Guangdong–Hong Kong–Macao Greater Bay Area

“…The study of Liu et al [59] on the Zengtang Reservoir in the Guangzhou City also confirms that anthropogenic interventions in production activities can greatly increase the amount of nutrients and heavy metals entering a water body, leading to reservoir eutrophication and ecosystem degradation. Other studies [60,61] suggest that heavy metals enter lakes through various pathways. For example, Cu and Zn from industrial and waste pollution [62] and agricultural fertilizer residues, as well as Pb from automobile exhaust emissions [57], are considered solid and persistent pollutants in many aquatic ecosystems [63].…”

“…For example, Cu and Zn from industrial and waste pollution [62] and agricultural fertilizer residues, as well as Pb from automobile exhaust emissions [57], are considered solid and persistent pollutants in many aquatic ecosystems [63]. A study of stratified soil samples from a brownfield in Jiangsu Province showed that the pathway of heavy metal (Cu, Ni, Pb, Cd, As and Hg) contamination is largely dependent on agricultural discharge from upstream river catchments [61].…”

Integrating ecohydrology and ecohydraulics

“…For instance, the habitat extent of larval and juvenile silvery minnow population in Rio Grande River (USA), in the special issue, has been successfully estimated using hydrology statistics, inundation extents based on hydraulic modelling and areal habitat availability based on a habitat suitability index curve, demonstrating a robustness in fish habitat management by validating the ecological model (Harris et al, 2024). (Yu et al, 2023).…”