Abstract:

The evolutionary patterns and existing states of groundwater contaminant plumes serve as the fundamental basis for formulating pollution control strategies, as their different developmental stages and spatial features directly influence the precision and effectiveness of remediation measures. Therefore, elucidating the dynamic evolution mechanisms of contaminant plumes and their governing factors holds significant importance for achieving scientific groundwater pollution management. The evolution process of groundwater contaminant plumes exhibits notable spatiotemporal heterogeneity and complexity. The duration and characteristics of each evolutionary stage are jointly influenced by multiple factors, including contaminant input flux, pollutant properties, aquifer lithology, groundwater flow dynamics, and seasonal variations. The intricate interactions among these factors pose substantial challenges to accurately assessing and predicting the evolutionary stages and existing states of contaminant plumes. Currently, there remains a lack of systematic and comprehensive quantitative assessment methodologies internationally. Although numerical models for groundwater contamination can predict the spatiotemporal distribution of pollutant concentrations, their predictive results cannot directly determine the developmental stages and evolutionary patterns of contaminant plumes. Moreover, numerical modeling imposes stringent requirements on data and parameters for characterizing hydrogeological conditions and contaminant properties. Most groundwater contamination sites fail to meet the extensive data prerequisites necessary for numerical simulations. To address these challenges, this study focuses on typical groundwater contaminants (including heavy metals and organic pollutants) prevalent in China and establishes a scientific framework for determining contaminant plume formation. It proposes that the evolutionary process of groundwater contaminant plumes is fundamentally governed by the dynamic equilibrium of key factors, including pollutant release mass, storage capacity of geological media, contaminant migration flux in groundwater, and destructive removal processes (e.g., microbial degradation). Building upon this, a multidimensional evaluation index system encompassing pollution sources, hydrogeological conditions, and pollutant interaction processes was developed, categorizing plume evolution into “expansion-maturity-recession” phases. Additionally, a quantitative assessment method for plume states was established. The research outcomes provide theoretical and technical support for identifying plume developmental stages and implementing differentiated remediation strategies. These findings hold practical significance for advancing precision control of groundwater pollution.

Key words: groundwater plume, evolution stage, expansion phase, recession phase, mature plume