Toward Standardized Microplastic Detection for Integrated Watershed and Aquatic Management

Mengshan Lee; Chichi Huang; Jing-Ru Chen

Microplastic pollution is an increasing global environmental challenge, with watersheds acting as major transport pathways delivering land-based plastics into aquatic and marine ecosystems. Microplastics serve as carriers for heavy metals and toxic compounds, and pose risks to ecosystem and human health. However, the absence of standardized analytical methods has limited data comparability and constrained effective watershed-scale pollution assessment. This study developed and validated a protocol for identifying microplastics in fish gastrointestinal tissues, with the aim of improving analytical reliability for watershed pollution monitoring. Five common plastic types (PP, PE, LLDPE, PLA, PHA) were subjected to pretreatment using fish intestinal tissue as an organic matrix. Digestion efficiency and plastic integrity were evaluated under varying digestion reagents, sample ratios, and digestion durations. Spectral integrity was assessed using ATR-FTIR, while surface morphology changes were examined via microscopy. Our results indicate that digestion with 30% hydrogen peroxide at room temperature for 96 hours effectively removed organic matter while preserving the chemical structure and morphology of all tested plastics. Compared to alkaline digestion, this method showed lower plastic degradation and higher recovery stability. Subsequent density separation using zinc chloride (1.63 g/cm³) and sequential glass fiber filtration (2.7 μm and 0.7 μm) enabled consistent and efficient microplastic recovery. Application of the standardized protocol to real fish samples confirmed its feasibility and reproducibility. The proposed method is low-cost, environmentally friendly, and operationally stable, making it suitable for routine laboratory analysis and field-based watershed monitoring. By improving data consistency and detection accuracy, this standardized approach enhances the assessment of microplastic contamination and supports science-based watershed management and pollution mitigation strategies.

Acid Mine Drainage Remediation in West Virginia at the Point and Watershed Scales

Nathan DePriest

Treatment of acid mine drainage (AMD) in West Virginia (WV) has primarily followed a point-source approach focused on individual National Pollutant Discharge Elimination System (NPDES) permitted discharges. Challenges to the point-source approach are evident in long-term liability and restoration efficacy due to the prevalence of unregulated AMD discharges. Alternatively, the watershed-scale approach to AMD treatment aims to treat sources of AMD throughout an entire watershed to maximize stream restoration and minimize treatment cost. Watershed-scale restoration can implement a combination of at-source, in-stream, and centralized treatment. Jurisdictional, regulatory, and technical feasibility challenges are associated with the watershed approach, but benefits are evident in financial and restoration outcomes. The watershed approach has been successfully implemented by the West Virginia Department of Environmental Protection (WVDEP) at the T&T AMD Treatment Plant in the Muddy Creek Watershed, Preston County, WV, where better restoration outcomes have been achieved at a lower long-term treatment cost compared to the point-source approach. WVDEP has expressed interest in implementing this approach in other watersheds. Through funding allocated in the Infrastructure Investment and Jobs Act (IIJA) to address impacts of AMD from abandoned mine lands (AML), the West Virginia Water Research Institute (WVWRI) was awarded a research project by WVDEP to identify and prioritize AMD-impacted watersheds in WV for implementation of the watershed-scale approach to AMD remediation. Two years of AMD characterization and remediation design have been completed and highlight the the need for a diverse approach to watershed-scale AMD remediation particular to the hydrologic and jurisdictional conditions within a given watershed.

Integrated Hydrological - Biogeochemical Modeling of LNAPL Biostimulation in Soil-Groundwater Environment

Akanksha Srivasta; Eldo T.I.

Groundwater pollution caused by light non-aqueous phase liquid (LNAPL) hydrocarbons persists to pose a serious global issue for public health and environment resulting from its persistent nature, mobility, and toxicity in the subsurface. The present work proposes an integrated hydrological-biogeochemical simulation strategy for evaluating the effectiveness of biostimulation for promoting LNAPL decomposition in soil-groundwater environments. This simulation study adopts a novel technique that integrates variable saturated flow along with multi-species reactive transport, including sequential degradation in the subsurface. Time-dependent microbial kinetics with electron acceptor dynamics are employed to capture the temporal and spatial shifts of subsurface redox gradients which regulate LNAPL biological degradation.

The key results of this integrated hydrological-biogeochemical modelling approach indicate a clear impact of biostimulation on LNAPL mobility and decomposition in soil-groundwater system. Biostimulation substantially stimulated the growth of bacteria by governing electron acceptor which led to faster decomposition rates as well as an apparent decrease in plume dimension and concentration. Furthermore, hydrological conditions emerged to possess substantial effects on dissolution behaviour and mitigation efficacy. These interactions underscore the relevance of site-specific hydrogeological variables in determining the effectiveness and sustainability of biostimulation-driven cleanup strategies.

This integrated hydrological-biogeochemical modeling gives a better understanding of how biostimulation strategies can significantly enhance LNAPL decomposition and assists in groundwater restoration planning and management. This modeling study findings provides a robust decision tool for risk assessments and site-specific cleanup strategies.