Linear Alkylbenzene Sulfonate Concentrations Research Articles

Exploring the potential of bacterial-augmented floating treatment wetlands for the remediation of detergent-contaminated water

Due to industrialization and urbanization, the use of detergents inadvertently led to contamination of aquatic environments, thus posing potential threat to aquatic organisms and human health. One of the main components of detergents is linear alkylbenzene sulfonate (LAS), which can cause toxic effects on living organisms, particularly aquatic life in the environment. In this study, floating treatment wetlands (FTWs) mesocosms were developed and augmented with LAS-degrading bacteria. The plant species, Brachiaria mutica (Para grass), was vegetated to establish FTWs and bacterial consortium (1:1:1:1) of Pseudomonas aeruginosa strain PJRS20, Bacillus sp. BRRH60, Acinetobacter sp. strain CYRH21, and Burkholderia phytofirmans Ps.JN was augmented (free or immobilized) in these mesocosms. Results revealed that the FTWs removed LAS from the contaminated water and their augmentation with bacteria slightly increased LAS removal during course of the experiment. Maximum reduction in LAS concentration (94%), chemical oxygen demand (91%), biochemical oxygen demand (93%), and total organic carbon (91%) was observed in the contaminated water having FTWs augmented with bacterial consortium immobilized on polystyrene sheet. This study highlights that the FTWs supported with immobilized bacteria on polystyrene sheets can provide an eco-friendly and sustainable solution for the remediation of LAS-bearing water, especially for developing countries like Pakistan.

Environmental concentrations of anionic surfactants in lake surface microlayers enhance the toxicity of Microcystis blooms: Insight from photosynthesis, interspecies competition, and MC production

Anionic surfactants represented by linear alkylbenzene sulfonate (LAS) exhibit vertical heterogeneity of concentrations in aquatic environments owing to their amphiphilic structure. Field investigations showed that the concentration of anionic surfactants (mainly LAS) in the water surface microlayer (SML) of Lake Taihu reached 580 μg/L, higher than that in the lower layer. Floating Microcystis blooms overlap in space with the high concentration of anionic surfactants in SML. However, few studies have focused on the effects of anionic surfactants (e.g., LAS) on the interspecies competition between toxic and nontoxic Microcystis. In this study, coculture and monoculture experiments were conducted with both toxic and nontoxic Microcystis species to explore how the environmental concentration of LAS regulates the dominance of toxic Microcystis and toxicity from the perspective of photosynthesis, species dominance, and MC production. The results showed that LAS concentrations above 0.267 or 0.431 mg/L (depending on light conditions) selectively promoted the photosynthetic competitive advantage of toxic Microcystis, leading to its higher population proportion in the community. Additionally, LAS concentrations above 0.5 mg/L induced the synthesis and release of microcystins (MCs). The results of chlorophyll fluorescence analysis, electron microscopy and transcriptome sequencing suggested that compared with nontoxic Microcystis, toxic Microcystis can better resist LAS stress by dissipating excess light, maintaining an intact membrane structure and maintaining cellular homeostasis. Transcriptome sequencing revealed that the photosynthetic damage of nontoxic Microcystis might be attributed to the impacts of LAS on the absorption and assimilation of nitrogen, which finally resulted in the degradation of phycobilisomes. This study can provide novel insight for establishing standards and safety management of wastewater discharge.

Biodegradation of Linear Alkylbenzene sulfonate-Anthracene Mixture by a Microbial Consortium isolated from Sediment

Linear alkylbenzene sulfonate and anthracene are chemical compounds which form pollutant mixtures with high toxic potential, causing damage to ecosystems. The process known as biodegradation is an effective, low-cost process carried out by microbial populations that reduces the toxic effect of linear alkylbenzene sulfonate and anthracene. In the present study, biodegradation was determined at different concentrations of linear alkylbenzene sulfonate, anthracene and the mixture of both compounds. The resulting reduction in toxicity produced by the mixture, the compounds separately and their biodegradation intermediaries was assessed using a microbial model. The ISO 9439 system was used to assess the biodegradation effect of a microbial consortium isolated from polluted sediment on 5, 10 and 20 mg/l of linear alkylbenzene sulfonate and the same concentrations of anthracene. Toxicity was determined by measuring inhibition of Bacillus cereus dehydrogenase activity produced by 0.25 ml aliquots of the linear alkylbenzene sulfonate, anthracene and the mixture of both compounds before and after they had been subjected to the biodegradation test. After 11 days, the linear alkylbenzene sulfonate -anthracene mixture was biodegraded to a greater degree than the compounds individually (3057.36 μmol CO2), but at a concentration of 20 mg/l of both compounds, a marked inhibition of biodegradation was observed. A reduction in toxicity produced by the biodegradation of linear alkylbenzene sulfonate and its mixture with anthracene at 5 and 10 mg/l respectively was observed.

Spatial modeling framework for aquatic exposure assessments of chemicals disposed down the drain: Case studies for China and Japan.

A modeling framework was created for the development of spatially explicit aquatic exposure models for any region or country of interest for chemicals disposed of down the drain. The framework relies on globally available data sets for river flow and population, and locally available data sets for wastewater treatment infrastructure and domestic water use, and leverages the iSTREEM® chemical routing algorithm. The framework was applied to China and Japan as case study countries. Spatially explicit population data were obtained from WorldPop. River flows covering the spatial extent of the two countries were derived from a high-resolution surface runoff gridded data set that was based on the Curve Number approach and combined with the hydrology network for catchments and rivers from HydroBASINS and HydroSHEDS data sets. Publicly available data from government sources were used for estimating per capita water use and wastewater treatment infrastructure. To demonstrate the framework, the China model was used to predict the levels of the antifungal agent climbazole in rivers across the country, and the Japan model was used to predict river concentrations of linear alkylbenzene sulfonate. For both chemicals, the comparison of measured to modeled values showed good agreement, using linear regression analysis (R2 ≥ 0.96). The framework presented in this study provides a systematic and robust approach to develop spatially resolved exposure models that can be extrapolated to any country or region, allowing more accurate risk assessment of chemicals disposed down the drain by leveraging concentration distributions generated by the model. Integr Environ Assess Manag 2022;18:722-733. © 2021 SETAC.

Study of the pollution by surfactants in a river of a high Andean micro basin

The surfactants linear alkylbenzene sulfonate (LAS), is used in large quantities in modern society, and wastewater containing it can contaminate groundwaters through runoff and sewers. The study aimed to determine the level of LAS in the Huatanay river; in Cusco city, Peru. Water samples were taken from nine points along the river, in the rainy and dry season in 2018. LAS surfactants were determined spectrometrically using methylene blue as indicator; dissolved oxygen (DO) and conductivity were also determined; both were correlated through Pearson coefficient at 5% significance, and analyzed in triplicate. The concentration of LAS in the dry season varied between 0.01 to 23.17 mg/L and in rains from 0.09 to 1.47 mg/L; the DO level shows values between 0.11 to 5.04 mg O2/L, and the conductivity varied from 777.7 to 2688.9 µS/cm. In conclusion, high levels of LAS considerably decrease the DO and increase the conductivity.

Comparison of the Efficiency of Ultraviolet/Ultrasonic (UV/US) and Ultraviolet/Zinc Oxide (UV/ZnO) Technologies as Advanced Oxidation Processes in the Removal of Linear Alkylbenzene Sulfonate (LAS), an Anionic Detergent, from Aqueous Media

Surfactants are one of the most commonly found xenobiotics in municipal and industrial wastewater. The purpose of this study was to compare ultraviolet/ultrasonic (UV/US) and ultraviolet/zinc oxide (UV/ZnO) processes in the removal of LAS from aqueous media.In this study, a medium-pressure UV lamp (125 W), an ultrasonic device (400 W and 42 kHz), and ZnO nanoparticles (NPs) were used. The concentration of LAS was 0.5, 14, and 21 mg/L in all experiments. Contact time of 8, 16, and 24 minutes, pH of 3, 7, and 11, and NP concentrations of 50, 100, 150 mg/L were selected. Detergent extraction was performed using methylene blue active substances.The results showed that the efficiency of UV/US process in the removal of LAS was 89.35%, while the removal efficiency of UV/ZnO process was 81.27%. In both processes, the rate of detergent removal increased by elongating the contact time from 8 to 24 minutes. The efficiency of UV/US process in LAS removal was greater than that of the UV/ZnO process. The findings showed that the removal efficiency of UV/US process was directly correlated with pH, while it had an inverse correlation with the removal efficiency of UV/ZnO process.

Quantitative determination of linear alkylbenzene sulfonate (LAS) concentration and simultaneous power generation in a microbial fuel cell-based biosensor

Linear alkylbenzene sulfonate (LAS), one of the most widely used synthetic surfactants in laundry detergent industry, is considered a hazardous contaminant in wastewater. In the present study, a microbial fuel cell (MFC) based biosensor is developed to quantitively determine the LAS concentration in wastewater. To do so, the developed MFC is fed with LAS concentration of 60 mg l−1. Finally, a sustained biofilm is formed after almost 34 days and the highest open circuit potential of 425 mV is recorded. The maximum power and current densities of 75 mW m−3 and 663 mA m−3 are obtained, respectively; and the internal resistance of the MFC-based biosensor is calculated to be about 1 kΩ. After 98 h, LAS removal and coulombic efficiency are 90% and 65%, respectively. A linear correlation between the current density and LAS concentration (in the range of 10–120 mg l−1) is obtained. Furthermore, a comprehensive model is used to interpret the output electrical signal of the MFC representing temporal and spatial distributions of different microorganisms as well as the hierarchal processes of the LAS biodegradation. The competition between electrogens and methanogens in the biofilm; and also, the effect of external resistance on electrogen concentration are shown as well. Besides, the MFC-based biosensor desirably performed as a power generator and purifier in addition to being an accurate biosensor.

Evaluation of Parameters in the Removal of Linear Alkylbenzene Sulfonate Anionic Surfactant Using Electrocoagulation

The objective of the present investigation was to construct an electrocoagulation cell in a batch system and to evaluate its capacity to remove the anionic surfactant of the linear alkylbenzene sulfonate (LAS), which is present in gray water determining the effect of the type of electrodes (Al or Fe), distance between electrodes (1, 1.5 and 2 cm) and voltages (10, 15 and 20 V). The experimental tests were carried out for 20 min. The dimensions of the short wave electrolysis cell built in glass were 26 cm long, 7 cm wide and 12 cm high, with 10 electrodes of 12x6 cm supported by a PVC structure. The concentration of LAS in the solution was determined by employing UV-Vis spectrometry applying the Methylene Blue Active Substances (MBAS) method. A higher removal of 65.55% was obtained when aluminum electrodes were used, and 69.11% with iron electrodes a separation of 1.5 cm and a voltage of 20 V, presenting less change in pH, conductivity, and energy consumption when using the Al3 electrode. When evaluating the effect of time at the best experimental configuration (Al, 1.5 cm, 20 V) it was established that the removal efficiency increased to 75.13% in 60 min. Electrocoagulation with aluminum electrodes is presented as an efficient alternative for the removal of LAS in solution.

Degradation of linear alkylbenzene sulfonate (LAS) using TiO2-chitosan composite as a photocatalyst

Linear Alkylbenzene Sulfonate (LAS) is an anionic surfactant that is widely used as an active ingredient in synthetic detergent formulation. Being a component in domestic waste, LAS can potentially be harmful to the environment. In this research, the degradation of LAS using TiO2-chitosan composite as a photocatalyst was investigated. The optimum dose of TiO2-chitosan to be used was determined, and the effect of pH towards the degradation effectiveness was also studied. The results showed that a dose of 1 g/100 mL composite at pH 6 gave an optimum result for the LAS degradation. In this optimum condition, the decrease in LAS concentration was up to 95.20% from its initial concentration.

Probabilistic human health risk assessment of linear alkylbenzene sulfonate (LAS) in water samples from Anzali Wetland, southwest of the Caspian Sea

Linear alkyl benzene Sulfonate (LAS) is a major anionic surfactant utilized in detergents around the world and is subsequently a ubiquitous water contaminant. This paper deals with assessing human health risk due to LAS in Anzali Wetland between different age groups. Water samples were collected from 50 stations in the wetland. LAS concentration was determined by spectrophotometry at 650 nm. The risk quotients (RQ) index was used to assess the human health risk assessment of LAS in the wetland. Based on the results, the health risk index was lower than 0.2 in all stations, indicating that there is no LAS contaminant risk for human health in this wetland. However, due to the presence of the different unregulated discharge of wastewater to the wetland, without strong policies to control and management, the risk of contamination may increase in the future.

Effect of Fine Bubbles on Removal of Linear Alkyl Benzene Sulfonate Surfactant during the Rinsing Stage of Laundry Washing

AbstractThe use of fine bubbles is a promising approach to remove surfactant efficiently during the rinsing process of clothing, to fulfill a requirement. Therefore, the influence of fine bubbles on the removal performance of surfactant from cloth during the rinse process of pulsator washing machine (top loading type) was investigated. The test apparatus was assembled by connecting a microbubble generation tank and a small washing machine with tubes and circulating fine bubble water to a small washing machine. Swatches of cloth with a specified amount of linear alkylbenzene sulfonate (LAS) adsorbed from aqueous solution, were rinsed with tap water, and the LAS concentration in the rinse water was examined with an HPLC system equipped with a high‐precision fluorescence detector. The average bubble diameter of the fine bubble water used was 0.13–1.4 μm. In the rinsing experiment, no difference was found in the final LAS removal efficiency between water with and without bubbles; but the former increased the LAS removal rate during the initial stage of rinsing. This tendency was particularly noticeable when the stirring power of the washing machine was weak. Therefore, it was concluded that the fine bubble effect on the removal of the surfactant is mainly a kinetic effect rather than an equilibrium effect.

Antagonism or synergism? Responses of Hydrocharis dubia (Bl.) Backer to linear alkylbenzene sulfonate, naphthalene and their joint exposure.

The presence of surfactants may affect the bioavailability of polycyclic aromatic hydrocarbons. A hydroponic experiment was conducted to investigate the response of Hydrocharis dubia (Bl.) Backer to different concentrations of linear alkylbenzene sulfonate (LAS), naphthalene (NAP) and their mixture (0.5, 5, 10, and 20mg/L) for 14 days and 28 days. The results showed that LAS had a greater toxic effect on H. dubia growth than NAP at treatment concentrations of 0.5-20mg/L. The combined effect of LAS and NAP was damaging to H. dubia at concentrations of LAS+NAP ≥5+5mg/L. When LAS+NAP ≥10+10mg/L, the underground parts of H. dubia suffered more significant damage than the aboveground parts. Under the treatments with LAS, NAP and their mixture, H. dubia experienced oxidative stress. Soluble proteins and antioxidant enzymes were the main substances protecting H. dubia from LAS stress, and superoxide dismutase (SOD) and peroxidase (POD) were the main protective enzymes. When exposed to NAP, H. dubia growth was stimulated and promoted at the same time. In the short-term treatment (14d), catalase (CAT) activity was sensitive to NAP stimulation, and soluble proteins and SOD were the main protective substances produced. Soluble sugars, SOD and ascorbate peroxidase (APX) played important protective roles during the longer exposure time (28d). The physiological response of H. dubia exposed to the combined toxicants was weaker than the response to exposure to individual toxicants. The responses of SOD and CAT activity were positive in the short term (14d), and these were the main protective enzymes. As the exposure time increased (28d), the plant antioxidant system responded negatively.

Anaerobic reactor applied to laundry wastewater treatment: Unveiling the microbial community by gene and genome-centric approaches

Gene and genome-centric approaches were applied to investigate the microbial taxonomic and metabolic diversity profiles from a lab-scale anaerobic reactor applied to laundry wastewater treatment with increasing concentrations of linear alkylbenzene sulfonate (LAS). Therefore, metagenomic analysis was carried out with reactor samples collected under three conditions, (i) Stage I, the reactor was fed with synthetic medium, (ii) Stage II, synthetic medium was replaced by diluted laundry wastewater with specific LAS loading rates (SLLRs) of 1.0 ± 0.3 mgLASgTVS−1d−1 and (iii) Stage III, SLLRs increased to 2.7 ± 0.7 mgLASgTVS−1d−1. Shotgun metagenomic sequencing was performed on an Illumina HiSeq 2 × 150 bp platform. Gene-centric analysis of each step of the metabolic pathway (fumarate addition, β-oxidation, ring cleavage and desulfonation) for anaerobic aromatic degradation showed eight over-representative genera (Achromobacter, Pelodictyon, Pseudomonas, Psychrobacter, Rhodococcus, Stenotrophomonas, Sulfurovum and Syntrophobacter), suggesting a microbial core with an important role in LAS biodegradation. Some of these genera were also recovered through a differential binning method, representing fifteen bacterial and one archaeal metagenome-assembled genomes (MAGs). Biodegradation pathway reconstruction of LAS using six MAGs unveiled the syntrophism for complete degradation of the LAS molecule. Only the MAGs with taxonomic annotation for Syntrophobacter showed genetic potential for fumarate addition, whereas in the ring cleavage, there was a predominance of genes in MAGs with taxonomic annotation for Pseudomonas fragi and Rhodococcus. This work represents the first report of genome-centric approach to study biological reactors applied in anionic surfactant degradation, contributing with detailed metabolic information of the key microbial actors in LAS degradation and opening perspectives for future biotechnological strategies aiming at bioaugmentation and/or biostimulation of indigenous microbial populations.

Screening and mutagenesis of high-efficient degrading bacteria of linear alkylbenzene sulfonates.

As a widely used detergent, anionic surfactant linear alkylbenzene sulfonates (LAS) is a common toxic pollutant in wastewater. In this study, Pseudomonas sp. strain H6 was isolated from activated sludge and municipal wastewater, which had good degradation effect on LAS. The results showed that strain H6 could grow with LAS as the sole carbon source. When the concentration of LAS was less than 100mg/L, strain H6 could degrade more than 80% of the LAS within 24h. Meanwhile, the growth of strain H6 increased with the increase of LAS concentration, reaching the maximum growth at the presence of 100mg/L LAS. When the concentration of LAS was over 100mg/L, strain H6's cell growth and degradation of LAS showed a downward trend due to the strong toxicity of LAS, and the degradation rate of LAS almost tended to zero with 500mg/L LAS. Further mutagenesis analysis of strain H6 showed that positive mutation occurred under ultraviolet and nitrite mutagenesis with using ampicillin to increase the screening pressure, and the degradation rate of LAS was 44.91% higher than that of original strain.

Globally applicable water quality simulation model for river basin chemical risk assessment

Abstract Many companies around the world need to assess water environmental risks in accordance with sustainable development goals (SDGs) set by the United Nations, environmental, social, and governance (ESG) investment, the Carbon Disclosure Project (CDP) water program, and also their corporate social responsibility (CSR) activities. Although companies have been requested to voluntarily evaluate their water risks and provide information thereon, the water quality risk in river basins is difficult to assess owing to insufficient monitoring information. This paper proposes the National Institute of Advanced Industrial Science and Technology - Standardized Hydrology-based AssessmeNt tool for chemical Exposure Load (AIST-SHANEL) model as a river water quality simulation model that can be employed for chemical risk assessment and evaluation of the effects of use of a company's consumer products on river basins. AIST-SHANEL is the only unsteady analysis model that estimates spatial and temporal chemical concentrations and assesses water quality within river basins by point/non-point emission of chemical substances. To evaluate the efficacy of AIST-SHANEL, a case study focused on the surfactant linear alkylbenzene sulfonate (LAS), found in the detergents of widely used health care products, was conducted. The water risk assessment was performed in three Japanese river basins with different watershed characteristics: Tama River in urban Tokyo with high sewerage penetration rate, Nikko River in urban Nagoya with a low sewerage penetration rate, and the nonurban None River with no sewerage. In Tama River, the LAS river water concentrations were found to be strongly influenced by seasonal variations as well as the flow rate associated with dilution and temperature-induced biodegradation. Their concentrations in Nikko River were strongly affected by flooding, indicating that the influence on their transport through the drainage channel was due more to low sewage levels than temperature-induced biodegradation. In None River, the LAS river water concentrations were only slightly affected by dilution. The river sediment concentrations of LAS in the three river basins showed mild seasonal variations. The 95th percentile of river water concentrations, predicted environmental concentration (PEC), at the most downstream and maximum concentration grids in the three river basins were 4.5 and 51.2 mg/m3 for Tama River, 30 and 58.6 mg/m3 for Nikko River, and 0.15 mg/m3 for None River. Neither of the PECs nor maximum values at these grids exceeded the predicted no-effect concentration (PNEC) of LAS (270 mg/m3), suggesting minimal ecological risk in these river basins over the year for all target river basins due to LAS. Furthermore, we analyzed a scenario in which LAS was substituted with the highly biodegradable alcohol ethoxylates (AE) for corporate self-management measures in Nikko River with only a few sewers, and therefore only a low risk. The AIST-SHANEL model has useful and widespread application with no need for monitoring by companies; as long as the relevant watershed characteristics can be obtained, water risk assessments of chemical substances can be performed for any river basin in the world.

Growth and Physiological Responses in Myriophyllum spicatum L. Exposed to Linear Alkylbenzene Sulfonate.

The exogenous organic pollutant linear alkylbenzene sulfonate (LAS) is frequently detected in water. Myriophyllum spicatum L., a submerged aquatic plant, is a popular choice for phytoremediation. The present study investigated the growth and physiological responses of M. spicatum to different concentrations of LAS (0, 0.1, 0.5, 1, 10, 50, 100, and 500 mg/L) after 14 and 28 d of treatment. After 14 d, higher LAS doses (50-100 mg/L) significantly reduced the growth of M. spicatum compared with controls. Plants died at 500 mg/L LAS. Chlorophyll a and total chlorophyll contents were markedly increased at higher doses of LAS (10-100 mg/L). Significantly enhanced peroxidase (POD) activity was found at 50 mg/L of LAS, and decreased superoxide dismutase (SOD) activity at 100 mg/L of LAS; other indices showed no significant changes under LAS stress. After 28 d, no significant effect was observed on the growth of plants exposed to LAS doses of 0.1 to 100 mg/L, whereas plants died at 500 mg/L LAS. Compared with controls. SOD activity increased significantly at 0.1 mg/L LAS and maintained the same level as controls at higher concentrations. At all LAS exposures, POD activity was higher than that of controls. Other indices for M. spicatum were not remarkably changed at 28 d. Our results indicate that the oxidative damage to M. spicatum caused by LAS stress after 28 d is clearly less than such damage at 14 d. Environ Toxicol Chem 2019;38:2073-2081. © 2019 SETAC.

In-situ activated nanoparticle as an efficient and recyclable foam stabilizer for enhancing foam separation of LAS

Linear alkylbenzene sulfonate (LAS) is a particular member of the emerging contaminants, because of its increasingly ubiquitous use and tremendous harm to the environment and wastewater treatment plant. Herein, we develop a novel two-stage foam separation to recover LAS (18.7-91.0 mg/L) from laundry wastewater. We first reported the fabrication of activated silica nanoparticle (SNP) via a facile and scalable in-situ approach. To obtain a desirable surface property, the key design element was the utilization of amphoteric surfactant, viz. cocamidopropyl betaine, as the modifier. In the first-stage, activated SNP could serve as an efficient foam stabilizer to improve the foam stability and the interfacial adsorption of LAS. Remarkably, LAS concentration in effluent decreased to very low levels of 1.9-2.9 mg/L with a proper enrichment ratio, and met the emission standard. In the second-stage, we originally adopted the intensification of liquid drainage to selectively recycle activated SNP from LAS. An inclined foam channel (IFC) covered by hydrophobic coating was constructed and the maximum recovery percentage of SNP reached 91.5%, indicating that the activated SNP was recyclable. This work definitely proves that the integration of nanotechnology in foam separation can make wastewater treatment more efficient and less expensive.

Historical analysis of domestic wastewater pollution and its measures in Lake Teganuma basin using surfactant concentrations recorded in sediment core samples

In order to learn whether it is possible to clarify the history of water pollution and its countermeasure from the fluctuation of chemicals accumulated in the sediment core of the lake, concentrations of linear alkylbenzenesulfonates (LAS) in sediment core samples collected from Lake Teganuma, which was severely polluted by domestic wastewater, were determined. The results were compared with concentrations of LAS in the lake water, waters of two large inflowing rivers, and in sewage from the Lake Teganuma basin. Sediment cores collected in 2003 and 2004 recorded the history of domestic wastewater pollution in the basin during the previous 25–35 years. LAS concentrations in the sediment core drastically decreased after the 1990s, and similar reductions of LAS were observed in the river and lake waters. Large amounts of LAS have still been used in the basin during 1980s to 2017, the drastic decrease of LAS concentrations in both the sediment and the river and lake waters is attributable the expansion of sewer system coverage in the basin since 1981. The effect of lake dredging was also estimated by the changes in surfactant concentrations. Thus, historical changes in not only pollution levels but also social factors can be assessed by determining sediment concentrations of chemicals in daily use such as LAS.

Characteristics of River Sites with Elevated Concentrations of Linear Alkylbenzene Sulfonate: Implications for Water Environmental Management for Protection of Aquatic Life

Characteristics of River Sites with Elevated Concentrations of Linear Alkylbenzene Sulfonate: Implications for Water Environmental Management for Protection of Aquatic Life

Evaluation of the anaerobic biodegradation of linear alkylbenzene sulfonates (LAS) using OECD 308 water/sediment systems.

Linear alkylbenzene sulfonates (LAS) are the most widely used anionic surfactants in household detergents and cleaning products. We have evaluated LAS anaerobic degradation in sediments following OECD 308 guidelines. Four different classes of sediments were collected from non-polluted areas and tested to check the influence of: fine and coarse texture, low and high organic carbon content, and freshwater and marine origin. The concentrations of LAS and possible degradation metabolites in sediment and water phases were monitored by high resolution mass spectrometry over an incubation period of 160 days. LAS removal was between 0 and 63%, depending on the sediment used, and it was accompanied by formation of sulfophenyl carboxylic acids (SPCs). The best results were observed for marine sediments having low organic carbon and silt + clay contents (0.5% and 13%, respectively), whereas degradation was negligible in freshwater sediments. The large differences in degradation observed across the sediments tested were attributed to their physicochemical properties influencing LAS bioavailability and the heterogeneity of microbial communities. Further research is also needed to address some shortcomings observed during the application of the OECD 308 and to ensure that test results obtained with these guidelines model anaerobic biodegradation under realistic environmental conditions.