Key Takeaways & Executive Findings
- •• • Tailings leakage events release up to 4.3×10^7 m³ of tailings (e.g., Samarco 2015), with suspended particulate matter (SPM) dispersing over 668 km, causing prolonged turbidity stress lasting months to years, far exceeding natural sediment-driven turbidity events. • • Tailings contain elevated concentrations of heavy metals (e.g., Zn, Pb, Cd, As) with high bioavailability; active forms dominate, leading to significant bioaccumulation and toxicity in aquatic organisms, as evidenced by long-term declines in benthic species richness. • • Combined physical (turbidity) and chemical (heavy metal) stress from tailings leakage induces synergistic toxicity through mechanical damage, light limitation, and oxidative stress, resulting in severe and often irreversible ecological damage, such as impaired fish swimming behavior and benthic community collapse. • • Bibliometric analysis (2000–2025) shows a rising global research trend on tailings toxicity, with China's publication output increasing significantly, reflecting growing attention to tailings dam leakage risks and their ecological impacts.
Abstract
Tailings dam leakage can cause secondary sudden water pollution events, imposing severe combined stress of high turbidity and heavy metal contamination on natural water bodies within a short period, threatening aquatic ecological security. Existing studies have systematically revealed the pollution characteristics and biological effects of such events, which are fundamentally distinct from natural high-turbidity water and industrial wastewater leakage. Compared with natural high-turbidity water, tailings leakage inputs finer particles with higher specific surface area, leading to more intense and prolonged turbidity stress. Meanwhile, heavy metals in tailings are more enriched than natural sediments, with higher proportions of active forms and bioavailability, causing significant bioaccumulation and toxic effects, and long-term decline in benthic community species richness. Compared with industrial wastewater leakage, tailings leakage simultaneously releases high concentrations of fine suspended solids and multiple heavy metals, forming a unique 'physical-chemical' combined stress. This synergistic effect amplifies biological toxicity through multiple pathways such as mechanical damage, light limitation, and oxidative stress, resulting in severe and often irreversible ecological damage, such as impaired fish swimming behavior and collapse of benthic community structure. Analyzing the long-term impacts of tailings leakage on aquatic ecosystems from the perspective of combined stress is helpful for providing scientific basis for emergency response and medium-to-long-term ecological risk prevention of related sudden water pollution events.
1. Introduction
Tailings dam failures represent a critical industrial hazard, releasing vast quantities of fine-grained tailings and associated heavy metals into aquatic systems. Unlike natural turbidity events or industrial point-source pollution, these incidents impose a dual stressor—elevated suspended solids and metal contamination—that acts synergistically on aquatic biota. The 1998 Aznalcóllar spill (6×10^6 m³ of pyritic sludge) and the 2015 Samarco dam rupture (4.3×10^7 m³) exemplify catastrophic scenarios where pH dropped to ~3 and dissolved oxygen was depleted, causing ecosystem collapse. Existing remediation strategies often overlook the combined physical-chemical stress, focusing solely on metal removal or turbidity control, thereby failing to address the compounded ecological damage.
This review synthesizes current knowledge on the combined stress mechanisms of tailings leakage, emphasizing the unique characteristics of fine particle suspension and metal bioavailability. By analyzing case studies and experimental data, we identify critical gaps in understanding long-term ecological impacts and propose a framework for risk assessment that integrates both physical and chemical stressors. The findings underscore the need for integrated monitoring and mitigation approaches that consider the synergistic effects of turbidity and heavy metals, providing a scientific basis for emergency response and ecological restoration in tailings-affected water bodies.
Loading authentic research manuscript (Pages 1–5)...
WANG Yuchen, XU Li, FENG Yanhui, ZHU Jialin, CAI Qijia, YAO Ling'ai, LIANG Rongchang, WANG Yuqi, XU Xuefeng, MA Qianli (2026). Research Progress on Combined Stress Effects of Secondary Water Pollution from Tailings Dam Leakage on Aquatic Organisms. Chinese Journal of Environmental Engineering. https://doi.org/10.12030/j.cjee.202511003
Research & Educational Purpose Only: The translations, structured abstracts, analytical annotations, and data reports provided by SinoGreenTechare intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoGreenTech claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What are the key differences in particle size distribution between tailings-derived suspended solids and natural sediments, and how do these differences affect turbidity persistence and ecological impact?
Tailings-derived particles are finer and have higher specific surface area compared to natural sediments, leading to slower settling and prolonged turbidity. For instance, in the Samarco disaster, SPM dispersed over 668 km, with elevated turbidity persisting for months to years. This prolonged exposure exacerbates light limitation and mechanical damage to aquatic organisms, causing more severe and sustained ecological stress than natural turbidity events.
How do heavy metals in tailings interact with suspended solids to produce synergistic toxicity in aquatic organisms?
Heavy metals in tailings are often present in bioavailable forms (e.g., exchangeable and carbonate-bound fractions) that can be readily taken up by organisms. The simultaneous presence of high suspended solids increases metal adsorption and ingestion, while physical stress from particles damages gills and other tissues, enhancing metal uptake. This combined effect leads to oxidative stress and histopathological damage, as observed in fish exposed to Fundão dam tailings, where metal bioaccumulation and physiological responses were significantly elevated.
What are the long-term ecological consequences of tailings dam leakage on benthic communities, and how do they differ from acute effects?
Long-term effects include chronic turbidity and metal exposure that reduce light penetration and smother benthic habitats, leading to declines in species richness and shifts in community composition. For example, studies after the Aznalcóllar spill showed that benthic communities did not fully recover even years later, due to persistent metal contamination and physical alteration of sediments. Acute effects, in contrast, cause immediate mortality and behavioral changes, but long-term sublethal effects may impair reproduction and growth, affecting ecosystem resilience.
What are the main challenges in assessing the combined stress of turbidity and heavy metals in tailings-affected waters, and how can they be addressed?
Challenges include separating the individual contributions of physical and chemical stressors, accounting for spatial and temporal variability, and extrapolating laboratory results to field conditions. Advanced approaches include using mesocosm experiments that simulate realistic mixtures, employing biomarkers that indicate specific stress pathways (e.g., oxidative stress enzymes), and integrating remote sensing and modeling to track SPM and metal dispersion. Such integrated methods can improve risk assessment and guide targeted mitigation strategies.
Related Chinese Research & Cross-Citations
Analysis of National and Local Policies for Medical Waste Treatment and Disposal in China
The escalating generation of medical waste, driven by healthcare expansion and frequent medical activities, poses significant environmental and public health risks. Under the framework of ecological civilization, China is developing a comprehensive policy system for medical waste treatment and disposal, yet the current framework remains nascent and exhibits inconsistencies between national and local policies. This study systematically analyzes the status of national and local policies from 2003 to 2024, collecting 413 policy documents (166 from national ministries and 247 from provincial governments). The analysis examines temporal evolution, regional distribution, and policy focus, alongside the influence of medical waste output, treatment technologies, facility infrastructure, and major epidemic responses. Findings reveal distinct policy phases: initial self-disposal, exploratory management, foundational system building, and rapid development. Regional disparities are pronounced, with eastern coastal areas showing more advanced policies due to greater technical and financial resources. The surge in medical waste, particularly during the COVID-19 pandemic, underscores the need for enhanced regulatory guidance. Non-incineration technologies are gaining traction for their environmental and cost benefits, and facility coverage has improved but remains uneven. The study proposes five policy principles to foster technological innovation and industrial upgrading, ensuring safe medical waste management and environmental protection.
Kinetic Analysis and Simulation of Pollutant Removal in Sewage Networks
This study investigates pollutant removal characteristics and kinetic behaviors in sewage networks, and analyzes their impact on the carbon-to-nitrogen ratio (C/N, as COD/TN) of influent to wastewater treatment plants. Source water quality sampling at drainage outlets revealed spatial and temporal variations in C/N, with domestic sewage exhibiting higher C/N than industrial sewage, and diurnal peaks reaching 6.92 versus 4.71 during off-peak hours. Using a pilot-scale adjustable sewage network system in Kunshan, experiments were conducted under high (0.491 m·s−1) and low (0.089 m·s−1) flow velocities, monitoring pollutant removal over 144 hours. Pseudo-first-order kinetics were applied to model COD and TN removal. Results showed that COD (including SCOD and PCOD), BOD5, and SS achieved approximately 80% removal within 144 h, with higher removal at low flow velocity. TN, NH3-N, and TP exhibited lower overall removal rates. Kinetic fitting revealed that COD removal rate constants (kCOD) were significantly higher than those for TN (kTN), and both decreased with increasing flow velocity: at low velocity, kCOD=0.0167 h−1 and kTN=0.0029 h−1; at high velocity, kCOD=0.0127 h−1 and kTN=0.0020 h−1. Simulations based on actual source pollutant concentrations indicated that the time for C/N to drop to the denitrification critical value of 4.50 was 12.24 h at high velocity, but shortened to 9.49 h at low velocity. These findings demonstrate that increasing flow velocity effectively retards the decline of C/N. Therefore, regulating network flow velocity to reduce hydraulic retention time is a key strategy for maintaining adequate C/N at the terminal and ensuring denitrification efficiency in wastewater treatment plants.
Preparation of Trimetallic-Carbon Composite Catalysts and Their Application in Catalytic Ozonation of Industrial Wastewater
Advanced oxidation processes (AOPs) are promising for degrading organic pollutants in water treatment. Heterogeneous catalytic ozonation (HCO) has gained attention due to its high oxidation efficiency, strong interference resistance, and low secondary pollution. In this study, a series of trimetallic-carbon composite ozone catalysts were prepared via an organic precursor calcination method using γ-Al2O3 as support. This method enhanced catalytic activity and mechanical strength while overcoming the limitations of carbon materials (low mechanical strength) and metal-based materials (poor mass transfer). The optimized catalyst, CA-FeCoCu, comprising Fe, Co, Cu, carbon, and alumina, exhibited excellent performance in phenol degradation and real industrial wastewater treatment. Characterization revealed that the synergistic effect of trimetals and the introduction of multiple carbon types increased specific surface area and hydroxyl radical (·OH) generation. In a pilot-scale fixed-bed reactor, the CA-FeCoCu/O3 system reduced COD from 120 mg·L−1 to below 40 mg·L−1, with an O3 consumption ratio (O/C) of less than 1, effectively lowering operational costs. This work provides a new strategy for developing efficient and stable heterogeneous O3 catalysts and offers a reference for the practical application of HCO in industrial wastewater treatment.
Differentiated Characteristics of Suspended Particulate Matter and Their Effects on Water Quality in the Middle and East Routes of the South-to-North Water Diversion Project
This study investigates the spatiotemporal differentiation of suspended particulate matter (SPM) characteristics, sources, and their impacts on water quality between the Middle Route (closed artificial channel) and East Route (open natural water system) of the South-to-North Water Diversion Project. Thirty sampling sites (13 on the Middle Route, 17 on the East Route) were established, and samples were collected during dry and wet seasons. Water quality parameters and SPM characteristics were analyzed, including particle size distribution, total suspended solids (TSS), chlorophyll a, and stable carbon and nitrogen isotopes. Results show that the Middle Route maintains good and stable water quality, with SPM dominated by coarse particles (>63 μm, 61.43%–94.68%), total phosphorus (TP) <0.01 mg·L−1, and a significant positive correlation between chlorophyll a and coarse particles (r=0.60), indicating algal aggregation dominates particle formation. In contrast, the East Route exhibits high and fluctuating nitrogen and phosphorus concentrations, with SPM dominated by fine particles (<20 μm, 51.26%–88.61%), TP ranging from 0.03 to 1.11 mg·L−1, and a positive correlation with fine particles, suggesting significant external inputs. Carbon and nitrogen isotope analysis reveals that Middle Route SPM primarily originates from autochthonous algae (contribution >46.75%), while East Route SPM is influenced by both terrestrial C3 plants and algae. The distinct engineering and management approaches of the two routes lead to significant differences in SPM characteristics and sources, thereby affecting water quality dynamics. The Middle Route requires an 'algal reduction and hydrodynamic optimization' strategy to control algal-derived coarse particle deposition, whereas the East Route benefits from 'retention-sedimentation and wetland purification' to reduce external fine particles and pollutant inputs. This research provides theoretical support and practical guidance for differentiated SPM management in long-distance water diversion systems.
Combined Ozone Micro-Nano Bubble Oxidation and Powdered Activated Carbon Adsorption for Removal of Taste and Odor Compounds from Drinking Water
Algal-derived taste and odor compounds (2-methylisoborneol, 2-MIB, and geosmin, GSM) in drinking water sources are poorly removed by conventional treatment. This study systematically evaluated the standalone and combined performance of ozone micro-nano bubbles (O3-MNBs) oxidation and powdered activated carbon (PAC) adsorption for removing 2-MIB, GSM, and algal cells from source water. Results showed that O3-MNBs pre-oxidation achieved >97.5% removal of odorants at 400 ng·L−1 and 67.2% algal cell removal within 30 min. When applied as a deep treatment stage, the degradation rate constant (k) was 10.1%–25.6% higher than in pre-oxidation due to lower background matrix interference. Both pre-oxidation and deep treatment reduced effluent concentrations of 2-MIB and GSM to below 10 ng·L−1, with oxidation kinetics fitting pseudo-first-order models (R²>0.95). PAC adsorption of both compounds followed pseudo-second-order kinetics (R²>0.99), with GSM equilibrium adsorption capacity approximately 20.0% higher than that of 2-MIB. In pure water, adsorption capacity increased by >10.0% compared to raw water. Based on kinetic models, a quantitative prediction method was established for O3-MNBs oxidation and PAC adsorption processes, aiming to achieve efficient odorant removal and cost optimization, providing theoretical support for advanced drinking water purification and smart water plant construction.
Pulsed Electric Field Enhancement of Nitrogen Removal Performance and Microbial Community Structure Response in Anammox Granular Sludge
This study investigated the effects of a ring-shaped pulsed electric field (PEF) (1.5 V, 4 h on-time per cycle) on nitrogen removal performance and microbial community structure of anammox granular sludge (AnGS). Two anaerobic sequencing batch reactors (R1 control, R2 with PEF) were operated under stepwise increasing nitrogen loading rates (NLR). At NLR below 1,155 mg·(L·d)−1, R2 exhibited total nitrogen removal efficiency (TRE) 7.5%–17.0% higher than R1, with biomass, specific anammox activity (SAA), and extracellular polymeric substances (EPS) increased by 5%–7%, 21%–71%, and 54%–77%, respectively. However, at NLR above 1,320 mg·(L·d)−1, the toxic effect of nitrite dominated, and PEF enhancement diminished or even reversed to inhibition. Microbial community analysis revealed that at low-to-moderate NLR, PEF increased the relative abundance of Planctomycetes and key anammox bacteria (Candidatus Brocadia and Candidatus Jettenia), along with enhanced community richness (Chao1) and diversity (Shannon/Simpson indices). At high NLR, PEF decreased microbial richness compared to R1. Principal component analysis and redundancy analysis indicated that PEF was the key factor driving community differences at low-to-moderate NLR, whereas nitrite concentration became the dominant factor at high NLR. This study provides theoretical support for enhancing the resilience and engineering application of anammox processes.