The environmental effects of surfactants have been studied from various perspectives, such as aquatic toxicity and biodegradability. Surfactants exhibit different physiochemical properties depending on their structural characteristics. This review discusses the relationship between surface tension and the interfacial activity of the most widely used surfactants (anionic and nonionic surfactants). This relationship is typically observed when surfactants and test animals used for toxicity test are fixed. First, this review discusses previous studies on the toxicity and surface tension as an interfacial property of surfactants. Then, an effect of water hardness, which is the most influential factor on both the toxicity and interfacial activity of anionic surfactants, is discussed using surface tension as an indicator. Thereafter, the change in the toxicity of anionic surfactants under different conditions are highlighted: different water hardness and adsorbent, primary biodegradation of linear alkylbenzene sulfonate, low water hardness in the presence of fatty acid salts, different water hardness for binary surfactant mixtures. Additionally, the review highlights the relation of toxicity changes and the surface tension change under each condition. This review aims to provide a better understanding of the toxicity of surfactants from the perspective of interfacial activity.

Norovirus (NoV) surveillance has been introduced as a national surveillance measure in many countries to monitor the epidemiology of NoV in a community. However, NoV surveillance in Malaysia is under-reported. This study was aimed to fill this research gap by capturing the prevalence of NoV GI and GII in Malaysia using wastewater-based monitoring. Monthly samples from three regional sewage treatment plants (RSTPs) located in Perak, Penang and Perlis were collected and processed from February 2023 to January 2024. NoV GI and GII were detected and quantified with real-time quantitative PCR. The seasonal distribution was analysed using rainfall data obtained from the Malaysian Meteorology Department. The results showed that NoV GI and GII were detected throughout the year at all RSTPs. NoV GII was identified as the predominant genogroup with detection rate of 94% out of total samples collected. The average viral loading per capita of each RSTP was estimated around 10⁶ genomic copies. Albeit no distinct seasonal correlation with rainfall was observed, two seasons of high viral load of total combined NoV GI and GII, were observed at all RSTPs. The two observed seasons; February–April 2023 and June–September 2023 coincided with the two inter-monsoon seasons in Malaysia.

High-performance liquid chromatography/high-resolution mass spectrometry (LC/HRMS) can be used to perform non-targeted analysis of dissolved organic matter (DOM) in environmental water at the molecular level without specifying target analytes prior to measurement. Pretreatment of samples subjected to LC/HRMS strongly affects the comprehensiveness of the analysis. In this study, the use of freeze-drying, vacuum vortex evaporation, and solid-phase extraction (SPE) for sample pretreatment was investigated as well as direct injection of untreated samples. Organic recovery, anion removal, and detected components were evaluated for Japanese urban river water with a high content of sewage effluent. Among the investigated techniques, SPE effectively removed anions and yielded the largest number of detected DOM components. Using the other three methods resulted in higher recoveries of organic matter than SPE but left residual inorganic ions that inhibited detection. Thus, SPE was determined to be the best single method for non-targeted screening analysis. Considering that some components were only detected using pretreatment methods other than SPE, it is recommended that SPE be combined with other methods to improve the comprehensiveness of the analysis.

On Bengkalis Island, Indonesia, coastal erosion discharges peat into the sea, which then returns to form a peat beach. Groundwater flows from peat cliffs to the sea, generating foam along the shoreline. Peat particles float on the sea surface and are attached to this foam. This study examined water quality, microorganisms, and the foaming properties of groundwater and seawater around the peat beach. High foaming properties of groundwater were observed, along with high dissolved organic carbon and nitrogen concentrations. Microorganisms in the groundwater in the peat beach were diverse, with an increase in actinobacteria, which decompose peat. Experimental data indicated that groundwater’s high foaming properties help float peat particles, affecting their transport. Peat flotation experiments showed increased flotation with higher groundwater concentration. The specific environment of the peat beach, such as neutral pH, may promote peat decomposition, with surfactants generating in the process affecting peat particle behavior. This study suggests that peat decomposition is enhanced on peat beaches where previously discharged peat particles have been deposited along the shoreline.

Possible salt-accumulating plant species were investigated for their potential in phytoremediation of the salinised farmland in the Karakalpakstan region, Uzbekistan, together with its methane fermentation for the post-treatment of biomass. The examined plant species of Amaranthus retroflexus, Atriplex nitens, Bassia scoparia, and Karelina caspia yielded the highest biomass at the end of August, whilst high salt uptake was found during their young stage in spring. Based on the biomass weight per plant, the salt content, and the cultivation density, A. nitens was the most promising species, which might remove the salt from the soil with about 1.8 kg-NaCl equivalent/kg-dry soil in the peak period. The result suggested the consecutive cultivation of the plant species for 3–6 years would rehabilitate the farmland to allow growth of wheat, sunflower, and sorghum. The kinetic model modified from IWA-Anaerobic Digestion Model No.1 (ADM1) showed the above four plant species had a similar biodegradability to that of the ordinary energy crop (Erianthus arundinaceus). The model predicted 60–70% of the biomass chemical oxygen demand (COD) could be converted to methane at an solids retention time (SRT) of about 50–60 days in an anaerobic digester. When the SRT was extended to 200 days, the methane conversion efficiencies were expected to reach about 80%.