Microplastic (MP) pollution has become a significant environmental concern, particularly in freshwater systems. However, little is known about the occurrence and characteristics of MPs in groundwater-fed freshwater sources such as natural springs. In this study, the presence, abundance and characteristics of MPs were investigated in freshwater natural springs across South Africa, representing different land-use types (i.e. rural and peri-urbanl) and spring type (i.e. modified and unmodified). On average, 6 particles per L (± 1.2 SD) of MPs were recorded, ranging between 2 (limit of quantification; LOQ) to 38 particles per L. Land-use and spring type did not show any significant influence on MPs abundance (p > 0.05). Overall, MPs exhibited diverse characteristics. Fibres (67.8%) were the predominant shape, while blue (28.8%) was the most common colour. The dominant size class was 100–250 µm across all springs, while the dominant polymer was polyethylene (PE; 46.8%). Our findings suggests that groundwater-fed water sources like natural springs, regardless of their limited exposure to above ground environment, are equally at risk of MPs contamination, similar to surface freshwater systems. This research provides empirical evidence on MPs contamination and monitoring of remote ecosystems, highlighting the ecological and social risk of MPs pollution in important freshwater resources. The study contributes valuable data for understanding MP dynamics including their densities and sources from groundwater-fed freshwater resources, offering insights into broader environmental pollution to African systems.
Petroleum hydrocarbon pollution in general, and benzene contamination of marine environments in particular, have had devastating effects on human health and bio-ecology. Furthermore, due to the insensitivity of conventional chemical methods in determining the early effects of harmful substance bioactivity at sublethal doses, there is a significant gap in the process of environmental protection and comprehensive planning in dangerous situations. This study systematically evaluates marine algae-based biomonitoring procedures for producing quantitative estimates of benzene-induced genotoxicity in coastal tropical seas and generating environmental health risk assessment models and early-warning systems. Four important macroalgae species (Gracilaria verrucosa, Chaetomorpha crassa, Caulerpa racemosa var. corynephora, and Caulerpa lentillifera) were tested as environmental health bio-sentinels under three environmentally relevant levels of benzene concentrations (83.10–983.49 µg/L) found in Asian coastal waters using exposure tests of 96 h. Alkaline comets were utilized as sensitive molecular sensors for assessing the genotoxic effects, resulting in hypersensitivity and species specificity. G. verrucosa was found to have the highest sensitivity (EC₅₀ = 83.7 µg/L). Probit regression modeling revealed strong dose–response associations (R2 > 0.92), enabling the identification of no-effect and biomonitoring protection limits. The bioassay detected early genotoxic signals at concentrations below established aquatic life protection thresholds, reinforcing its value as a sensitive biomonitoring tool for coastal environments. Its 96-h turnaround time enhances operational efficiency for continuous environmental health surveillance, enabling early-warning detection, supporting regulatory compliance in coastal water-quality management, and contributing to global environmental quality standards and marine health security initiatives.
Comprehensive overview of the marine algae-based biomonitoring protocol for benzene genotoxicity assessment. The workflow illustrates: (1) Selection of four tropical macroalgal species as bio-sentinels, (2) 96-h controlled exposure to environmentally relevant benzene concentrations, (3) DNA damage assessment using alkaline comet assay, (4) Species-specific dose–response relationships with G. verrucosa as the most sensitive indicator (EC₅₀ = 83.7 μg/L), and (5) Application in a four-tier environmental risk framework for coastal water-quality management. This protocol provides a cost-effective early-warning system for petroleum pollution monitoring in tropical marine ecosystems.
Hexafluoropropylene oxide (HFPO) compounds, including hexafluoropropylene oxide dimeric acid (HFPO-DA) and its ammonium salt (GenX), hexafluoropropylene oxide trimer acid (HFPO-TA), and hexafluoropropylene oxide tetrameric acid (HFPO-TeA), have been used as substitutes for phased-out legacy per- and polyfluoroalkyl substances (PFAS). Due to their extreme chemical stability, high water solubility, and persistence, these compounds have increasingly been detected in various water bodies, raising significant environmental and public health concerns. This review focuses on studies published between 2021 and 2025, summarizing the current knowledge on the removal efficiencies of various treatment technologies, including adsorption, ion exchange resins, membrane filtration, electrochemical oxidation, and advanced oxidation processes specifically targeting HFPO compounds. The main mechanisms governing their removal are hydrophobic interactions, ion exchange, and radical-induced degradation. However, the short-chain length and ether-linked structures of HFPOs limit the effectiveness of many conventional treatment methods. Recent research has placed particular emphasis on degradation-based approaches, which can achieve high removal or partial defluorination under optimized laboratory or pilot conditions. However, such outcomes often require high energy input and may generate transformation products, limiting their direct field applicability. At the same time, several engineered adsorbents and ion-exchange materials have demonstrated removal rates of 99% or higher in clean matrices, highlighting that no single strategy is universally superior. Overall, integrated treatment approaches that combine adsorption, separation, and degradation are increasingly recognized as necessary to achieve effective and sustainable remediation of HFPO-contaminated water,
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