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Surfactants present in natural surface waters negatively affect the self-purification processes of water due to foaming, oxygen deficiency and eutrophication of water reservoirs. Consumed with water, they adversely affect human health. The purpose of the research conducted in the period from 2019 to 2022 was to determine the effectiveness of removing anionic and non-ionic surfactants in the process of artificial infiltration carried out at surface water intakes. The research was carried out on an experimental field installation located at the surface water infiltration intake. The experimental installation consisted of three metering wells (piezometers) located on the way between the infiltration pond and the collecting well. Water samples collected from the pond, from piezometers and from the well allowed to assess the change in concentrations of selected surfactants during the flow of water through the ground from the pond to the well. The analysis of the content of non-ionic surfactants was carried out by the method of iodobismutane determination with the final measurement of bismuth-thiourea (BiAS-thio) absorbance. A simplified method for the determination of anionic surfactants using methylene blue (MBAS) was used to measure the concentration of anionic surfactants. The presented studies carried out during the pandemic in 2019–2022 show a significant increase in the concentration of non-ionic surfactants in water collected from the infiltration pond. The presented research results indicate that artificial infiltration can be treated as a robust and effective barrier eliminating surfactants from treated water before the treatment plant technology. The main effect of surfactant removal occurs in the first section of the ground flow. Interpretation of the results allowed to conclude that the sediment layer at the bottom of the infiltration pond plays a major role in the removal of surfactants. Biodegradation is the main process responsible for the removal of non-ionic and ionic surfactants in the infiltration process. [ABSTRACT FROM AUTHOR]

Terrestrial anionic surfactants (AS) enter the marine environment through coastal region. Despite that, in general limited knowledge is available on the coastal AS transfer pathway. This paper aims to assess the distributions and exchange of AS in the Peninsular Malaysia coastal environments, adjacent to the southern waters of South China Sea and Strait of Malacca. An assessment case study was conducted by a review on the available data from the workgroup that span between the year 2008 and 2019. The findings showed that AS dominated in the sea surface microlayer (SML, 57%) compared to subsurface water (SSW, 43 %). AS were also found to have dominated in fine mode (FM, 71 %) compared to coarse mode (CM, 29 %) atmospheric aerosols. SML AS correspond to the SSW AS (p < 0.01); however, highest enrichment factor (EF) of the SML AS was not consistent with highest SSW AS. Direct AS exchange between SML and FM and CM was not observed. Furthermore, the paper concludes AS mainly located in the SML and FM and could potentially be the main transfer pathway in the coastal environment. [ABSTRACT FROM AUTHOR]

This study determines the levels of surfactants at 12 stations located in the Melaka River Estuary. This river estuary is located within a tourism area of Melaka Historical City. The concentrations of anionic and cationic surfactants in the sea surface microlayer (SML) and sub-surface water (SSW) were determined by using two colorimetric methods, methylene blue active substances (MBASs) and disulphine blue active substances (DBASs), respectively. The results showed that cationic surfactants as DBAS (ranging between 0.19 and 0.25 μmol L−1) dominated the concentrations of surfactants in SML. The enrichment factor (Ef) between MBAS and DBAS in the SML and SSW ranged between 1.0 and 2.0, and 1.0 to 1.4, respectively. There was no significant correlation (p > 0.05) between MBAS and DBAS for both SML and SSW. Nevertheless, there were strong correlations (p < 0.05) between both MBAS and DBAS in the SML and SSW. The results showed the potential contribution of degradation processes of organic substances microorganisms in SSW towards the concentrations of surfactants in SML. Compared to previous studies, tourism-related activities may influence the concentrations of surfactants, especially DBAS, in this river estuary. [ABSTRACT FROM AUTHOR]

Quantitative determination of dodecyl sulfate and dioctyl sulfosuccinate has been performed with methylene blue dye in titration mode. The new approach consists in the titration of surfactant solution by standardized dye solution, simultaneously measuring absorbance at 660 nm with an immersion probe. Due to the formation of sparingly soluble ion pairs, the registered photometric titration curves are dependent on surfactant concentration. The analytical signal is the titrant volume needed to reach a certain absorbance value. The main advantage of the proposed method is that no toxic organic solvent is used. An additional advantage is that the analysis procedure can be carried out using an automatic titrator. The determination range is dependent on the end-point absorbance value. Standard deviation values fall in the range from 2 to 7 %. The method may be useful for routine process control in the surfactant industry. [ABSTRACT FROM AUTHOR]