Search Results (81)

Microplastics (MPs)—synthetic polymer particles less than 5 mm in size—have emerged as ubiquitous contaminants in terrestrial and aquatic environments worldwide, raising concerns about their ecological and human health impacts. While research has predominantly focused on urban and marine settings, evidence shows that rural ecosystems are also affected, challenging assumptions of pristine conditions outside cities and coasts. This review synthesizes current knowledge on the presence, pathways, and impacts of MPs in rural environments, highlighting complex contamination dynamics driven by both local sources (agricultural plastics, domestic waste, rural wastewater, and road runoff) and regional processes (atmospheric deposition, hydrological transport, and sediment transfer). Key findings highlight that rural lakes, streams, soils, and groundwater systems are active sinks and secondary sources of diverse MPs, predominantly polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET) in fibrous and fragmented forms. These particles vary in size, density, and color, influencing their transport, persistence, and bioavailability. Ecological effects include bioaccumulation in freshwater species, soil degradation, and potential food chain transfer, while human exposure risks stem from contaminated groundwater, air, and locally produced food. Despite these growing threats, rural systems remain underrepresented in monitoring and policy frameworks. The article calls for context-specific mitigation strategies, enhanced wastewater treatment, rural waste management reforms, and integrated microplastics surveillance across environmental compartments. Full article

Microplastics represent an emerging threat to aquatic environments and organisms, as they infiltrate water systems, are ingested by marine species, and cause physical harm, endocrine disruption, and bioaccumulation up the food chain, potentially impacting biodiversity and human health. Aquatic ecosystems face considerable harm from microplastic pollution because fish in the early developmental stages, including embryos, larvae, and juveniles, are more susceptible due to their immature physiological and detoxification systems. This review aims to comprehensively explore the impacts of microplastics on the early life stages of fish. Aquatic environments receive primary and secondary MPs from urban runoff and industrial waste, together with degraded plastics, which affect fish embryos and larvae via direct ingestion, surface adhesion, and trophic transmission pathways. The physical impact of MPs causes digestive tract blockages that reduce hatching success and create developmental problems in fish organs, but chemical toxicity develops from plasticizers, heavy metal leaching, and pollutant adsorption, which causes oxidative stress, endocrine disruption, and metabolic dysfunction. Survival rates decrease because exposure causes fish to perform poorly during swimming activities and make limited efforts to avoid predators. The small dimensions and high chemical reactivity of MPs increase their bioavailability, which promotes tissue penetration and leads to accumulation at different levels of the food chain. This comprehensive review emphasizes that we need to establish uniform detection protocols, long-term exposure research, and effective strategies to control MP pollution. The resolution of these difficulties remains essential for protecting fish populations, as well as for protecting biodiversity and minimizing seafood contamination risks to human health. Full article

Increasing levels of chloride in surface water are associated with detrimental effects on water quality, aquatic ecosystems, infrastructure, and human health. Numerous mass-balance studies have inferred watershed transport processes by interpreting chloride inputs and outputs, but few represent internal dynamics explicitly. We constructed a coupled water/chloride mass balance model to gain insights into storage, residence time, and transport processes in a 10-km² urban watershed. The model, which operates over a 10-year period at a daily time scale, represents storage in a dynamic soil-moisture reservoir, quick-flow runoff from storm events, and slow-flow runoff that sustains streamflow in dry weather. The calibrated model accurately represented (a)the observed transition from a streamflow enrichment regime in cold months to a dilution regime in warmer months, (b) the observed tendency for late-summer concentrations to be higher after winters with heavy snowfall, and (c) a period-of-record downward trend in chloride concentration likely associated with a downward trend in annual snowfall. Estimated chloride inputs averaged 195 metric tons per year, while the average output was 270 metric tons per year. In contrast, estimated storage was only 107 metric tons. The estimated mean residence time in groundwater was 1.27 years. This short residence time indicates that efforts to reduce inputs will manifest as decreased concentrations in streamflow on a management-relevant time scale of several years. The coupled mass balance model yielded insights into internal watershed dynamics that would not be possible from simple input/output analysis; such models can be useful tools for gaining insight into small watershed hydrology and pollutant transport. Full article

Urban lakes are essential for ecological balance and urban development. This study developed a comprehensive framework to evaluate the ecosystem health of urban lakes in China. Nineteen representative lakes from four lake zones were examined using three decades of remote-sensing data combined with hydrological, water-quality, and aquatic–biological investigations. An extended DPSIR model guided the selection of 52 indicators, and a hierarchical weighting scheme was used: the analytic hierarchy process determined criterion-level weights, while principal component analysis with Softmax normalization was used for indicator-level weights. The established index system was applied to Xuanwu Lake and Erhai Lake, and an obstacle-degree model was used to identify key ecological constraints from 2010 to 2020. Results showed that urban lakes in the Yunnan–Guizhou Plateau and Eastern Plain zones were mainly constrained by eutrophication and intensive urbanization, with state- and impact-related indicators contributing most to the health index. The framework captured the decline of Xuanwu Lake, driven by poor water exchange and external nutrient loading, and its subsequent improvement following governance interventions, as well as the post-2014 degradation of Erhai Lake driven by climate-induced hydrological stress and non-point source pollution, providing a practical tool for diagnosing constraints and supporting adaptive, region-specific lake management. Full article

Landscape spatial patterns are critical drivers of ecological processes, including nutrient cycling from terrestrial to aquatic systems, which ultimately modulate microorganism biodiversity. The emergence of robust spatial analysis tools now makes it possible to disentangle these complex relationships through controlled scenario generation. This study assesses the influence of land use and land cover (LULC) configuration on the export of total nitrogen (TN) and total phosphorus (TP) in an anthropogenically impacted river basin. We characterized the baseline landscape and generated synthetic LULC scenarios using the rflsgen (version 1.2.2) R package. Landscape metrics were calculated with landscape metrics, and nutrient export was modeled with the Nutrient Delivery Ratio (NDR) module of InVEST. The results demonstrate that spatial arrangement of the landscape is a key determinant of nutrient dynamics. Agriculture and urban areas have the greatest impact on nutrient export. Nutrient delivery is maximized when these LULC classes are configured in large, compact, and simply-shaped patches with high connectivity, which facilitates efficient hydrological transport. Conversely, fragmented natural grasslands and aggregated forests with regular shapes are associated with lower nutrient export, highlighting their role as nutrient sinks. This integrative methodology provides a novel framework for reproducible spatial experiments, offering evidence-based insights for land-use planning aiming to mitigate eutrophication and enhance ecosystem health. Full article

Nitrogen eutrophication represents a significant environmental challenge in Chinese aquatic ecosystems, exacerbated by rapid agricultural intensification, industrial expansion, and urban development. This review consolidates existing knowledge on the drivers and impacts of nitrogen pollution in Chinese aquatic ecosystems, with a focus on environments such as lakes, rivers, and coastal waters. The primary sources of nitrogen enrichment are excessive fertilizer application, livestock manure discharge, industrial emissions, and untreated industrial and municipal wastewater. These inputs have led to severe ecological consequences, including harmful algal blooms, hypoxia, loss of biodiversity, and deteriorating water quality, threatening ecosystem health and human well-being. The review also examines mitigation strategies implemented in China, encompassing regulatory policies such as the “Zero Growth” fertilizer initiative, as well as technological advancements in wastewater treatment and sustainable farming practices. Case studies highlighting successful interventions, such as lake restoration projects and integrated watershed management, demonstrate the potential for effective nitrogen control. However, persistent challenges remain, including uneven policy enforcement, insufficient public awareness, and gaps in scientific understanding of nitrogen cycling dynamics. This review aims to inform future efforts toward achieving sustainable nitrogen management in China by synthesizing current research and identifying key knowledge gaps. Addressing these issues is crucial for safeguarding China’s aquatic ecosystems and promoting global nutrient stewardship. Full article

Urban industrialization is a major driver of water pollution, particularly through emerging contaminants that pose significant health risks for humans and ecosystems. This critical review focuses on Bangladesh’s Buriganga and Dhaleshwari rivers, which pass through highly industrialized and urban areas, analyzing contaminant types, sources, pathways, and impacts. By synthesizing data from studies published between 2005 and 2024, the paper examines pollutants such as heavy metals (e.g., Cr, Cd, Pb, Ni, Zn, Hg, As, Mn, Cu, Fe) and microplastics in water, sediments, and biota. The Buriganga River shows extreme heavy metal contamination, with surface water Cr concentrations reaching up to 167,160 μg/L, Pb up to 3830 μg/L, and Fe up to 30,000 μg/L, and sediment Cr up to 4249 μg/g, Pb up to 3312 μg/g, and Fe up to 15,435 μg/g. In contrast, the Dhaleshwari River exhibits elevated but comparatively lower heavy metal concentrations in surface water (e.g., Cr up to 3350 μg/L; Cd up to 1890 μg/L; Pb up to 1320 μg/L; Ni up to 1732 μg/L; Fe up to 6040 μg/L) and sediments (Cr up to 282 μg/g; Fe up to 14,375 μg/g). Microplastic contamination in Buriganga is widespread across water, sediments, and biota and dominated by polymers such as polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). Industrial discharges, particularly from the textile, leather, and metal processing industries, are identified as primary sources for heavy metals and microplastics. Additional inputs from domestic waste, agricultural runoff, and municipal sewage intensify pollution, with Cr, Cd, and Pb notably frequently exceeding safety thresholds. Microplastics, originating from municipal waste and atmospheric deposition, persist in these rivers, posing ecological and public health risks. The persistence and bioaccumulation of heavy metals and microplastics threaten aquatic biodiversity by disrupting food chains and pose significant risks to local communities that depend on these rivers for agriculture, fishing, and daily water use. This review highlights the urgent need for comprehensive bioaccumulation studies, long-term monitoring, and enhanced detection techniques to better assess contamination levels. Strengthening environmental regulations, improving waste management, and adopting sustainable industrial practices are critical to mitigating emerging contaminant impacts and safeguarding these vital river ecosystems and public health. Full article

Plasticizers and bisphenols are contaminants of concern in the environment, particularly in aquatic ecosystems. Bivalve molluscs are effective bioindicators due to their benthic nature, their ability to filter water, and their capacity to bioaccumulate persistent pollutants. This study analyzes plasticizers and bisphenols in three native clam species (Ruditapes decussatus, Cerastoderma glaucum, and Polititapes aureus) from two Sicilian lagoons under different levels of anthropogenic pressure: the urbanized Capo Peloro lagoon (Ganzirri Lake) and the less impacted Oliveri–Tindari lagoon. The clams, together with water and sediment samples, were collected in winter 2023. Both groups of clams from the two sampling areas contained phthalates such as DMP, DEP, DiBP, and DEHP, as well as non-phthalate plasticizers such as DEHT, DBA, DEA, and DEHA. The sum of non-phthalate plasticizers (NPPs) was consistently higher than the sum of phthalates in all clam samples, confirming the emerging trend of NPPs. This trend was also observed in the water and sediment samples, regardless of the sampling area. The presence of structural analogues of bisphenol A (BPA) highlights the growing prevalence of BPA-like structures in aquatic environments. Given the increasing evidence of widespread and persistent contamination of aquatic environments by plasticizers and bisphenols, it is evident that these substances pose a significant threat to ecosystems and human health. Full article

With the rapid progression of global industrialization and urbanization, emerging contaminants (ECs) have become pervasive in environmental media, posing considerable risks to ecosystems and human health. While multidisciplinary evidence continues to accumulate regarding their environmental persistence and bioaccumulative hazards, critical knowledge gaps persist in understanding their spatiotemporal distribution, cross-media migration mechanisms, and cascading ecotoxicological consequences. This review systematically investigates the global distribution patterns of ECs in aquatic environments over the past five years and evaluates their potential ecological risks. Furthermore, it examines the performance of various treatment technologies, focusing on economic cost, efficiency, and environmental sustainability. Methodologically aligned with PRISMA 2020 guidelines, this study implements dual independent screening protocols, stringent inclusion–exclusion criteria (n = 327 studies). Key findings reveal the following: (1) Occurrences of ECs show geographical clustering in highly industrialized river basins, particularly in Asia (37.05%), Europe (24.31%), and North America (14.01%), where agricultural pharmaceuticals and fluorinated compounds contribute disproportionately to environmental loading. (2) Complex transboundary pollutant transport through atmospheric deposition and oceanic currents, coupled with compound-specific partitioning behaviors across water–sediment–air interfaces. (3) Emerging hybrid treatment systems (e.g., catalytic membrane bioreactors, plasma-assisted advanced oxidation) achieve > 90% removal for recalcitrant ECs, though requiring 15–40% cost reductions for scalable implementation. This work provides actionable insights for developing adaptive regulatory frameworks and advancing green chemistry principles in environmental engineering practice. Full article

Urban river ecosystems are increasingly threatened by anthropogenic activities, with wastewater discharge being a significant contributor. The complex nature and diverse sources of wastewater pose challenges in assessing its impact on water quality and ecological health. This study investigated the distribution, toxicity, and ecological effects of organic pollutants in an urban river system during the dry season. A comprehensive analysis was conducted of 16 phthalate esters (PAEs), 16 polycyclic aromatic hydrocarbons (PAHs), and 8 antibiotics, with a focus on several key pollutants. The results revealed distinct pollutant profiles: Dibutyl phthalate (DBP), Dimethyl phthalate (DEHP), and Diisobutyl phthalate (DIBP) were the predominant PAEs, while Chrysene was the most abundant PAH. Among antibiotics, Oxytetracycline and Norfloxacin were the dominant compounds. Wastewater treatment plant (WWTP) effluents significantly altered the composition of organic pollutants in receiving waters. Although dilution reduced the concentrations of some pollutants, certain organic compounds were detected for the first time downstream of the WWTP, and some specific compounds exhibited increased concentrations. Toxicity prediction using the Concentration Addition (CA) model identified DBP as the primary contributor to overall toxicity, accounting for the highest toxic load among all detected pollutants. Furthermore, WWTP effluents induced significant shifts in microbial community structure downstream, with incomplete recovery to upstream conditions. Integrated analysis of 16S rRNA gene sequencing, water quality assessment, and toxicity prediction elucidated the multifaceted impacts of pollution sources on aquatic ecosystems. This study provides critical insights into the composition, spatial distribution, and toxicity characteristics of organic pollutants in urban rivers, as well as their effects on bacterial community structure. The findings offer a scientific foundation for urban river water quality management and ecological protection strategies. Full article

Anthropogenic pollution of watersheds significantly threatens aquatic ecosystems, biodiversity, and human health. The present review examines the primary sources of contamination in river catchments, including industrial effluents, agricultural runoff, and urban wastewater discharge. The presence of pollutants degrades water quality, disrupting aquatic habitats and leading to adverse outcomes, including biodiversity loss, eutrophication, and declining fish populations. It also focuses on strategic mitigation approaches, including implementing stricter waste management regulations, adopting sustainable agricultural practices, improving wastewater treatment infrastructure, and public education initiatives. The article summarizes several biotechnological techniques developed to decrease the impact of farming activities on water quality. It also emphasises directions that could be followed concerning specific water chemical indicators, such as the residual quantity of heavy metals. Emphasis is placed on the need for integrated policy frameworks and cross-sector collaboration to safeguard freshwater systems and ensure long-term environmental sustainability. Full article

Tyre wear particles (TWPs), generated from tyre-road abrasion, are a pervasive and under-regulated environmental pollutant, accounting for a significant share of global microplastic contamination. Recent estimates indicate that 1.3 million metric tons of TWPs are released annually in Europe, dispersing via atmospheric transport, stormwater runoff, and sedimentation to contaminate air, water, and soil. TWPs are composed of synthetic rubber polymers, reinforcing fillers, and chemical additives, including heavy metals such as zinc (Zn) and copper (Cu) and organic compounds like polycyclic aromatic hydrocarbons (PAHs) and N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD). These constituents confer persistence and bioaccumulative potential. While TWP toxicity in aquatic systems is well-documented, its ecological impacts on terrestrial environments, particularly in agricultural soils, remain less understood despite global soil loading rates exceeding 6.1 million metric tons annually. This review synthesizes global research on TWP sources, environmental fate, and ecotoxicological effects, with a focus on soil–plant systems. TWPs have been shown to alter key soil properties, including a 25% reduction in porosity and a 20–35% decrease in organic matter decomposition, disrupt microbial communities (with a 40–60% reduction in nitrogen-fixing bacteria), and induce phytotoxicity through both physical blockage of roots and Zn-induced oxidative stress. Human exposure occurs through inhalation (estimated at 3200 particles per day in urban areas), ingestion, and dermal contact, with epidemiological evidence linking TWPs to increased risks of respiratory, cardiovascular, and developmental disorders. Emerging remediation strategies are critically evaluated across three tiers: (1) source reduction using advanced tyre materials (up to 40% wear reduction in laboratory tests); (2) environmental interception through bioengineered filtration systems (60–80% capture efficiency in pilot trials); and (3) contaminant degradation via novel bioremediation techniques (up to 85% removal in recent studies). Key research gaps remain, including the need for long-term field studies, standardized mitigation protocols, and integrated risk assessments. This review emphasizes the importance of interdisciplinary collaboration in addressing TWP pollution and offers guidance on sustainable solutions to protect ecosystems and public health through science-driven policy recommendations. Full article

Land use and land cover changes driven by urbanization and agricultural expansion have increasingly degraded the ecological health of stream ecosystems across watersheds. In Republic of Korea, the Ministry of Environment has designated riparian zones to protect water quality and preserve aquatic ecosystems and continues to implement policies for their management. Given the long-term nature of riparian zone management, providing robust scientific evidence to justify and refine these policies is imperative. In this study, we quantitatively evaluated the role of riparian vegetation on water quality and aquatic ecosystems by using Bayesian Networks. Scenarios were designed to compare the individual effects of riparian vegetation and combined effects of urban and agricultural land use changes. The results indicated that riparian vegetation positively influenced water quality and the benthic macroinvertebrate index at the sub-watershed scale. When riparian vegetation and land use factors were jointly adjusted, scenarios with high riparian vegetation coverage showed improved probabilities of good BMI scores—24.3% under highly agricultural conditions and 27.4% under highly urbanized conditions—highlighting a substantial vegetation effect, particularly in urban areas. This study provides a scientific basis for guiding future riparian restoration and management efforts. Full article

Urban streams undergo significant ecological alterations due to urbanization, including hydrological changes, water contamination, and biodiversity loss. This research employs a combination of satellite and drone imagery alongside traditional chemical and geophysical methods, facilitating a multi-dimensional assessment of Almyros and Gazanos urban stream health in Heraklion (Crete, Greece). The satellite imagery, obtained from the Copernicus program, allows for monitoring land use and impervious surface density around the streams, while drone surveys capture high-resolution images and calculate various water quality indices. In addition, chemical analyses of water samples for pollutants, as well as geophysical measurements using spectral induced polarization (SIP) and electromagnetic scanning (GEM-2), provide insight into the integrity of aquatic and riparian ecosystems. The study reflects on the different types of anthropogenic pressure faced by these two ecosystems. Almyros stream exhibits signs of eutrophication, characterized by elevated levels of chlorophyll and the presence of algal blooms, possibly due to runoff from adjacent agricultural activities. Conversely, the Gazanos stream shows signs of pollution mostly related to urbanization. The findings emphasize that both streams are under increasing anthropogenic pressure, thus highlighting the importance of employing comprehensive methods for effective stream management and policy implementation. This study ultimately advocates for ongoing monitoring initiatives that embrace technological advancements to safeguard urban water ecosystems. Full article

The accumulation of antibiotic resistance genes (ARGs) in aquatic systems jeopardizes public health and ecological environments. This study investigates ARGs dissemination in freshwater and seawater, focusing on the sources, prevalence and influencing factors. In freshwater, ARGs primarily originate from medical/pharmaceutical wastewaters, industrial operations, agriculture, and livestock sectors. By contrast, in addition to the above sources, seawater is contaminated by mariculture and terrestrial runoff. Comparative analysis indicates that fresh water hosts multidrug resistance, bacitracin resistance, sulfonamides, aminoglycosides, and beta-lactams, whereas seawater exhibits a wider range of ARGs encompassing sulfonamides, tetracyclines, aminoglycosides, beta-lactams, quinolones, macrolides, and chloramphenicol resistance genes. There was a stronger correlation between antibiotics and ARGs in seawater than in freshwater, especially in farmed waters. Human activities significantly contribute to ARGs pollution in both freshwater and seawater. Urbanization influences ARGs pollution in freshwater, while offshore distance and coastal economic development dictate ARGs selection pressure in seawater. This study shed lights on the current ARGs pollutant status in marine and freshwater ecosystems in China, providing a scientific foundation for water health preservation and ecosystem safeguarding measures. Full article