Water Environment Research最新文献

Quantifying how sedimentary architecture governs groundwater quality remains a critical research challenge in hydrogeology. This challenge spans from hydrochemical evolution to public health impacts. To address this knowledge gap, we developed an integrated quantitative framework to analyze the complete "geological-to-health" pathway in the northwestern Tangshan piedmont alluvial plain. We conducted a systematic analysis of 42 groundwater samples using three complementary approaches: hydrochemical characterization, absolute principal component score-multiple linear regression (APCS-MLR) receptor modeling, and health risk assessment. This multi-method investigation demonstrates the fundamental control of sedimentary architecture over groundwater systems. This study establishes that groundwater in the study area is predominantly of the weakly alkaline HCO₃-Ca·Mg type. Ion correlation analysis indicates that mineral dissolution (mainly carbonates and evaporites) governs groundwater chemistry and enhances NO₂ ^- migration through increased ionic strength. Gibbs diagrams, ion ratios, and saturation index (SI) collectively demonstrate that sedimentary architecture exerts fundamental control over hydrogeochemical processes. The chemical evolution is primarily governed by coupled carbonate precipitation and evaporite dissolution. High-permeability zones within this architectural framework facilitate anthropogenic contamination. APCS-MLR receptor modeling quantifies the anthropogenic contribution at 20.7%, while also revealing that all contaminant sources are constrained by architectural heterogeneity. Health risk assessment identifies F^- as posing the most significant noncarcinogenic risk. Hazard indices for infants (3.318) and children (2.903) substantially exceed those for adults (1.288). These findings establish a mechanistic framework linking subsurface architectural heterogeneity to public health outcomes. This framework provides a transferable paradigm for predictive groundwater quality management.

Reverse osmosis (RO) and nanofiltration (NF) processes are considered "best available technologies" by the US Environmental Protection Agency for perfluoroalkyl and polyfluoroalkyl substance (PFAS) remediation from water. While these processes are industry standard for applications such as desalination, commercial membranes are typically tailored to said applications, so different membrane products may show differing PFAS rejection behavior based on proprietary manufacturing methods or surface modifications. Additionally, there are limited studies reporting rejection trends of ultrashort-chain (USC) compared to short-chain (SC) and long-chain (LC) PFAS. This work benchmarks a total of 13 commercial RO or NF membranes for eight PFAS, spanning all size classes, under standardized conditions for rejection performance. A comparison of overall PFAS rejection across the membranes showed statistically significant differences in performance, indicating that membranes do not uniformly reject PFAS equally and highlighting the role of membrane chemistry on performance. A strong positive correlation between measured salt rejection and overall PFAS rejection was found. Lastly, USC and SC species were found to have similar rejection while LC species showed significantly higher rejection. These findings emphasize the importance of membrane selection when designing a system for PFAS remediation and provide new insight into PFAS rejection behavior relative to other species and salts.

This study aimed to identify the primary drivers of spatial and temporal variations in chlorophyll-a (Chl-a) concentrations and to improve the prediction accuracy of Chl-a concentrations at two adjacent weirs-Seungchon Weir (SC Weir) and Juksan Weir (JS Weir)-in the Yeongsan River, Korea. Utilizing over a decade of high-frequency monitoring data combined with a gradient boosting (GB) regression model, we investigated the conditions leading to high Chl-a concentrations, which are indicative of algal blooms. The results indicate that JS Weir frequently experiences extreme Chl-a concentrations (> 100 μg/L) under low discharge conditions (< 20 m³/s). Seasonal analysis revealed that diatoms dominated algal blooms at JS Weir during the colder months, which contradicts the conventional expectation of more intense summer blooms given the typically low temperatures and light availability in winter. Discharge rate and water temperature exhibited inverse relationships with Chl-a concentrations, and the GB model revealed a lagged multiday discharge effect. Water temperature and total organic carbon at JS Weir were identified as the most influential predictors of Chl-a concentrations. Parameters from SC Weir also showed high importance, confirming upstream-to-downstream connectivity along the 22-km reach between SC Weir and JS Weir. Integrating upstream data enhanced predictive accuracy for downstream bloom conditions. This research provides a foundation for coordinated weir operation-optimizing sluice gate control and upstream nutrient management-to mitigate algal blooms in regulated river systems. These management strategies can improve water quality and protect ecosystem health.

This study aimed to analyze evidence on the physical, chemical, and microbiological risks associated with dental wastewater (DWW) and its impact on the environment and human health. As part of a scoping review, we searched the PubMed, Scopus, and Web of Science databases for studies that described DWW management, characterization, filtration, and associated risks. The search was limited to studies published in English, including experimental, laboratory, observational studies, and reviews. We extracted the study design, country of origin, sample location, components, objectives, and results. Using VOSviewer software, an analysis of author coauthorship and keyword co-occurrence was conducted. Environmental and human risks were examined, and strategies to minimize damage were discussed. The search initially yielded 1967 articles until June 2024. After removing duplicates and applying exclusion criteria, 29 articles were selected for inclusion. Most studies (55.1%) were experimental, with heavy metals being the most frequently studied pollutants (60%), particularly mercury (Hg). Microbiological analyses appeared in six studies (20.6%), and bisphenol A in two studies (6.9%). The environmental pollutant potential of DWW was reported in 22 studies (75.8%), while only five studies (17.2%) documented risks to humans. In conclusion, DWW poses significant environmental hazards due to its toxic composition and pollutant potential. Although evidence on human health risks is still limited and fragmented, preliminary findings suggest possible concerns that warrant attention. These results highlight the urgent need for more comprehensive studies and support the implementation of regulatory and management strategies to mitigate environmental and potential human health impacts.

The benefits of incorporating biochar and iron as alternative materials to improve septic effluent quality were assessed and compared to C33 sand, a traditional material used to construct septic system soil treatment areas. This study used sequential batch tests to investigate pollution reduction performance of C33 sand, eight types of biochar, and three types of iron with various dosages to identify and optimize operational parameters. Pseudo-first-order and pseudo-second-order kinetics models were used to simulate temporal performance of wastewater treatment and identify likely mechanisms driving improvements in septic effluent quality. Softwood pine (SP) biochar was most effective at reducing biological oxygen demand (BOD), total nitrogen (TN), and fecal coliform (FC) in septic effluent, while treatment with iron-enhanced-sand (IES) produced the highest removal efficiency for total suspended solids (TSS) (> 80%) and total phosphorus (TP) (> 95%) among substrates tested. Experimentation revealed dosages that achieved optimal pollutant removal from 50-mL septic effluent were 5-g C33 sand, 1-g SP, or 2-g IES. Kinetics study showed that the pseudo-second-order model generally described the adsorption performance better than the pseudo-first-order model regardless of materials (average R² value > 0.95). Furthermore, the pseudo-second-order model simulated adsorption capability (mg g^-1) at equilibrium status with a lower percent error when compared to the pseudo-first-order model results. Based on these results, incorporation of SP and IES as alternative materials can achieve higher contaminant removal efficiency and produce cleaner septic effluent, thereby benefiting the environment.

This study assessed the drinking water supply, sanitation practices, and water quality in the peri-urban area of the Afeumey watershed, Cameroon, with the aim of identifying the main factors influencing water quality and their implications for human health. A mixed methodological approach combining household surveys and field sampling was employed. Thirteen water samples were collected from wells, springs, boreholes, and rivers during a hydrological period and analyzed for physicochemical, hydrochemical, and bacteriological parameters, including pH, TDS, EC, TSS, major ions, BOD₅, COD, fecal coliform, and fecal streptococci. The survey data revealed that 77% of the population relies on groundwater sources, mainly wells (34%), springs (24%), and boreholes (19%), whereas only 15% of residents are served by the CAMWATER distribution network. Sanitation systems are predominantly individual, with 54% of households using semimodern latrines and 65% of solid waste being disposed of in open or unregulated sites. These practices, coupled with high population density and insufficient drainage systems, exacerbate the risks of contamination of surface and groundwater resources. Hydrochemical analyses indicate that water in the Afeumey watershed is generally acidic (pH 3.34-6.13) and characterized by variable mineralization, with EC ranging from 39.5 to 668 μS/cm and TDS from 28 to 467 mg/L. The ionic composition follows the order Ca²⁺ > Mg²⁺ > Na⁺ > K⁺ and NO₃ ^- > HCO₃ ^- > Cl^- > SO₄ ^2-, reflecting both natural mineral dissolution and anthropogenic inputs. Elevated concentrations of total suspended solids, nitrate, ammonium, and bacterial indicators surpass WHO and ANOR standards for drinking water, suggesting strong domestic and agricultural influence. Principal component analysis (PCA) identifies two main components explaining 69.34% of the total variance, linking physicochemical variability to both geogenic and anthropogenic origins. The overall findings highlight deteriorating groundwater quality driven by poor sanitation infrastructure and unmanaged solid waste. The study underscores the urgent need for integrated water resource management, improved sanitation systems, regular water quality monitoring, and community education to ensure safe water access and sustainable environmental protection in peri-urban watersheds of Cameroon.

Although phosphorus is essential for living organisms, its release into the environment requires strict control due to pollution concerns. This study investigated the potential of phosphorus removal from water by manganese oxysulfide (MnO_xS_y) synthesized using a one-pot chemical precipitation method. Phosphorus adsorption capacity obtained as 42.1 mg/g (initial phosphorus concentration, 105.0 mg/L; pH 4.95; adsorbent dosage, 1 g/L). The adsorption mechanism included phosphorus speciation, MnO_xS_y protonation, electrostatic attraction, and redox adsorption. Phosphorus was removed by chemisorption as indicated by pseudo-second order kinetics (R², 0.9963-0.9999) forming monolayer coverage on MnO_xS_y (Langmuir, R² 0.9775). Negative ΔH° and ΔG° values revealed that the adsorption was exothermic and spontaneous, confirming energetic favorability at ambient temperature. The phosphorus removal efficiencies in real liquid digestate (86.7% ± 0.7%), simulated nutrient-rich wastewater (87.9% ± 0.1%), and only phosphorus added solution (93.1% ± 1.8%) were also comparable. These results indicated that MnO_xS_y is a promising adsorbent for the treatment of phosphorus from aqueous environment.

This study presents an integrated assessment of water quality in the Haraz Dam reservoir, considering both external pollutant inflows and internal contributions from a nearby unregulated landfill. The CE-QUAL-W2 hydrodynamic model was employed to simulate monthly variations of nitrate, phosphate, ammonium, dissolved oxygen, and pH across four water withdrawal levels, capturing the effects of thermal stratification and anaerobic conditions. Nitrate and phosphate were identified as the main drivers of water quality degradation, with the baseline Iran Water Quality Index for Surface Water Resources-Conventional Parameters (IRWQIsc) values classifying the reservoir as "relatively poor." Four management scenarios were evaluated: Scenario 1, reducing nitrate and phosphate inflows by 50%, improved IRWQIsc by 9.5 points, and lowering nitrate and phosphate concentrations by 46.8% and 41.6%, respectively, and shifting water quality to "average." Scenario 2, maintaining current pollutant loads over 5 years, predicted IRWQIsc values consistently below 40 at lower withdrawal levels, indicating ongoing poor water quality. Scenario 3, applying a sustained 50% reduction over 5 years, further improved IRWQIsc by 10 points, with nitrate and phosphate reductions of 52.7% and 51.6%. Scenario 4, removing the nitrate-contaminated leachate spring, reduced nitrate in the agricultural withdrawal level by only 4.9%, highlighting the limited impact of intrareservoir interventions alone. These results demonstrate that watershed-level management of pollutant inflows is essential for achieving long-term improvements in reservoir water quality, offering a replicable framework for hydrodynamic and water quality modeling in dam reservoirs.

Imidazolium ionic liquids (ILs) have gained significant attention in recent years due to their unique properties and potential applications. However their degradation and toxicity have become a growing concern. This study investigated the UV-light assisted photo-Fenton-like degradation of three imidazolium ILs, viz., 1-ethyl-3-methylimidazolium chloride (IE), 1-butyl-3-methylimidazolium chloride (IB), and 1-hexyl-3-methylimidazolium chloride (IH) and explored the degradation pathway by computational approach using density functional theory (DFT). This process efficiently degraded the ILs in the range 79.78%-84.78% in 120 min at 25 ± 1°C. The degradation rate follows the sequence IE > IH > IB with rate constants (k) 1.511 × 10^-2, 1.34 × 10^-2, and 1.30 × 10^-2 min^-1, respectively. The DFT calculations revealed that the degradation pathway involves hydroxyl radical attack on either the methyl or alkyl substituted chain followed by imidazolium ring opening. This study provides new insights into the degradation pathway of imidazolium ILs and highlights the potential of the photo-Fenton-like process for wastewater treatment.

Anaerobic digestion (AD) of condensate or aqueous pyrolysis liquid (APL) derived from municipal wastewater solids was successfully achieved both as a sole substrate and as a co-digestate with synthetic sludge, overcoming toxicity challenges previously associated with APL degradation. Key strategies that enhanced APL conversion to methane included optimizing the solids retention time (SRT) and organic loading rate (OLR) to mitigate APL toxicity, using an acclimated inoculum, and employing APL ozonation prior to digestion. Gas chromatography-mass spectrometry analysis confirmed APL constituents were removed in the process. Inoculum biomass from an industrial waste digester (IB) exhibited better performance in APL degradation compared to inoculum from a municipal digester (MB). APL ozonation enhanced methane production in IB-inoculated co-digesters, achieving 98% of the maximum stoichiometric methane. Microbial community analysis showed that hydrogenotrophic methanogens predominated in syntrophy with acetate oxidizing bacteria in IB-inoculated reactors, whereas both acetoclastic and hydrogenotrophic methanogens were present in MB-inoculated co-digesters. This study demonstrates that APL can be digested alone or as a co-substrate, emphasizing the importance of appropriate SRT, OLR, and inoculum selection. Co-digestion could be a viable strategy for wastewater resource recovery facilities that operate digesters for sludge treatment and may incorporate wastewater solids pyrolysis in the future.