Effects Of Linear Alkylbenzene Sulfonate Research Articles

Study of the Effect of the Surfactant Linear Alkylbenzene Sulfonate (LAS) on the Coagulation of Aged Microplastic

Objective: Evaluate the effect of linear alkylbenzene sulfonate (LAS) surfactant on the coagulation of aged microplastic.   Theoretical Framework: Chemical coagulation is one of the steps adopted in water treatment that can help remove microplastics. During coagulation, suspended particles agglomerate, increasing the efficiency of removing these particles in the sedimentation stage. However, when coagulation occurs in the presence of surfactants, evidence points to deficits in removal capacity.   Method: Using Jar Test tests, the optimal parameters for microplastic removal were determined with aluminum sulfate as a coagulating agent in the presence and absence of the surfactant linear alkyl benzene sulfonate (LAS). The LAS concentrations studied were in the range of 20 mg/L to 300 mg/L. Microplastic removal efficiency was evaluated by measuring turbidity.   Results and Discussions: The combination of pH and coagulant concentration values that best suited the system were 5.0 and 4.25 mg/L, respectively. Due to the addition of surfactants, a decrease in removal efficiency was observed, with an average value ranging from 94.79% to 76.50% due to the interaction of polyethylene spheres with the surfactant.   Research Implications: As explained, due to the coexistence of microplastics and surfactants in the aqueous environment, studies that describe chemical coagulation under these conditions have great value for optimizing treatment systems and technologies.   Research Originality/Value: The use of aged microplastics aims to approximate their natural occurrence.

Growth and physiological responses of submerged macrophytes to linear alkylbenzene sulfonate (LAS)

The potential toxic effects of linear alkylbenzene sulfonate (LAS), widely used in commercial detergents and cleaners, on submerged macrophytes remain unclear. We conducted a two-week exposure experiment to investigate LAS toxicity on five submerged macrophytes (four native and one exotic), focusing on their growth and physiological responses. The results showed that lower concentrations of LAS (< 5 mg/L) slightly stimulated the growth of submerged macrophytes, while higher doses inhibited it. Increasing LAS concentration resulted in decreased chlorophyll content, increased MDA content and POD activity, and initially increased SOD and CAT activities before declining. Moreover, Elodea nuttallii required a higher effective concentration for growth compared to native macrophytes. These findings suggest that different species of submerged macrophytes exhibited specific responses to LAS, with high doses (exceeding 5 ∼ 10 mg/L) inhibited plant growth and physiology. However, LAS may promote the dominance of surfactant-tolerant exotic submerged macrophytes in polluted aquatic environments.

Effect of linear alkylbenzene sulfonate on the uptake of microcystins by Brassica oleracea and Solanum tuberosum.

Globally, hypereutrophic conditions in major water reservoirs used for irrigation purposes, promote the co-existence of cyanotoxins and other pollutants such as linear alkylbenzene sulfonate (LAS). LAS is known to alter the permeability of membranes and promote the uptake of other pollutants by plants. In light of the potential human health risks and prevailing hypereutrophic conditions in some catchments in South Africa, we investigated the combined effects of LAS and microcystins (MCs) on food plants when cyanobacteria infested water is used to irrigate terrestrial crops. To understand the potential risks, pot-culture experiments were conducted to assess the effect of LAS on the accumulation of MCs in Brassica oleracea (cabbage) and Solanum tuberosum (potato) plants. The plants were watered with dam water containing 3.48 mg L -1 of the LAS (sodium dodecyl sulfate) and MCs (MC-LR: 10.47 ± 3.879; 6.158 ± 4.127 for MC-RR and 8.160 ± 2.544 for MC-YR μg L -1) for 20 days. The presence of LAS, at environmentally relevant concentrations in the irrigation water, did not enhance the uptake of MCs in the two plants, as demonstrated by statistically insignificant differences in the means of the treatments (with and without LAS). In addition, the presence of LAS, high pH, electrical conductivity (EC), and cyanotoxins in the water did not affect the total chlorophyll or the well-being of the plants. However, in some cases the levels of MCs bioaccumulated by the two plants exceeded the WHO recommended tolerable daily intake (TDI). These findings imply that the tested levels of LAS and MCs did not have any synergic effects on the two plant species, but irrigating food crops with such water still poses a human health risk.

Effect of linear alkylbenzene sulfonate on the uptake of microcystins by Brassica oleracea and Solanum tuberosum

Background Hypereutrophic conditions in major water reservoirs used for irrigation purposes in South Africa promote the co-existence of cyanotoxins and other pollutants such as linear alkylbenzene sulfonate (LAS). LAS is known to alter the permeability of membranes and promote the uptake of other pollutants by plants. In light of the potential human health risks and prevailing hypereutrophic conditions in some catchments in South Africa, we investigated the combined effects of LAS and microcystins (MCs) when cyanobacteria infested water is used to irrigate terrestrial crops. Methods To understand the potential risks, pot-culture experiments were conducted to assess the effect of LAS on the accumulation of MCs in Brassica oleracea (cabbage) and Solanum tuberosum (potato) plants. The plants were watered with dam water containing 3.48 mg L-1 of the LAS (sodium dodecyl sulfate) and MCs (MC-LR: 10.47 ± 3.879; 6.158 ± 4.127 for MC-RR and 8.160 ± 2.544 for MC-YR μg L-1) for 20 days. Results The presence of LAS, at environmentally relevant concentrations in the irrigation water, did not enhance the uptake of MCs in the two plants, as demonstrated by statistically insignificant differences in the means of the treatments (with and without LAS). In addition, the presence of LAS, high pH, electrical conductivity (EC), and cyanotoxins in the water did not affect the total chlorophyll or the well-being of the plants. However, in some cases the levels of MCs bioaccumulated by the two plants exceeded the WHO recommended tolerable daily intake (TDI). Conclusions These findings imply that the tested levels of LAS and MCs did not have any synergic effects on the two plant species, but irrigating food crops with such water still poses a human health risk.

The effect of linear alkylbenzene sulfonate (LAS) on microbial community structure of attached sludge in a down-flow hanging sponge (DHS) reactor treating municipal sewage

The effect of linear alkylbenzene sulfonate (LAS) on microbial community structure of attached sludge in a down-flow hanging sponge (DHS) reactor treating municipal sewage

Effect of linear alkylbenzene sulfonate (LAS) on the coagulation of ZnO nanoparticles in aqueous matrix

Effect of linear alkylbenzene sulfonate (LAS) on the coagulation of ZnO nanoparticles in aqueous matrix

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.

Hepatotoxicity of the anionic surfactant linear alkylbenzene sulphonate (LAS) in bullfrog tadpoles

The liver of anurans play an important role in metabolism, including detoxification, the biotransformation of molecules, and the storage of metabolites. Surfactants are part of domestic and industrial effluents. The effects of linear alkylbenzene sulfonate (LAS) on anuran liver remain unknown, however, some studies have evaluated the effects of LAS on the skin, gills, heart, testes, and liver of fishes. Here, we tested the hypothesis that LAS is hepatotoxic, promoting morphometric alterations in hepatocytes along with inflammation in the tissue, altering hepatic catabolism. We evaluated the effects of a LAS concentration that is considered environmentally safe in Brazilian inland waters on the liver of Lithobates catesbeianus tadpoles, including studies on morphology, morphometry, immunology, and metabolism. LAS exposure promoted enlargement of liver sinusoids and vacuolization of hepatocytes. Exposure to LAS also increased the area of mast cells and melanomacrophages (MMs). Additionally, LAS exposure increased hemosiderin inside MMs, suggesting alterations in the catabolism and storage of iron. Hepatocyte size increased after exposure to LAS, suggesting cytotoxic effects. Integrative analyses (i.e., morphometric, metabolic, and immunological) demonstrated hepatotoxic effects of LAS. These types of studies are key to understanding the negative effects of these substances on tadpole health, as these liver alterations impair anuran homeostasis.

Effect of anionic surfactant inhibition on sewage treatment by a submerged anaerobic membrane bioreactor: Efficiency, sludge activity and methane recovery

The effect of linear alkylbenzene sulfonate (LAS), a typical anionic surfactant, on the sewage treatment by a submerged anaerobic membrane bioreactor (SAnMBR) was investigated by a 243days operation. The changes of treatment efficiency, methane recovery and sludge activity due to the presence of LAS in sewage was studied in detail. Compared with control (96.8% and 2.87L/d), lower COD removal (95.2%) and biogas production rate (2.11L/d) were found at a LAS dosage of 5mg/L. Besides, LAS was removed by adsorption rather than degradation on the sludge (30–70%). Its adsorption can lead to significant loads in sewage sludge, which then decrease the methane production activity. The recovery efficiency of potential bioenergy was decreased by 20% and 26% at LAS of 2.5mg/L and 5.0mg/L, respectively. The results indicated that LAS had a more negative effect on the acetoclastic methanogens than acidogenic microbiota and the LAS inhibition to methanogen activity was responsible for the decrease of SAnMBR performance. Moreover, LAS caused a higher membrane fouling rate than the control experiment due to the microbial self-protection behavior in coping with the LAS in sewage. SAnMBR was hence not suitable to dispose LAS containing sewage with higher concentration.

음식물류 폐기물의 수소 발효 시 linear alkylbenzene sulfonate의 영향

This study examines the effects of linear alkylbenzene sulfonate on hydrogen fermentation of food waste. The hydrogen production rate was similar with different linear alkylbenzen sulfonate (LAS) concentrations. The maximum hydrogen yield increased with increasing LAS concentration. The highest maximum hydrogen yield was <TEX>$0.550{\pm}0.005mol$</TEX> H2/mol hexose at LAS for 5.52 mg/L. But the maximum hydrogen yield decreased above LAS for 11.05 mg/L. The concentration of acetate in control reactor was increased, but it decreased with increasing LAS concentration in other reactors.

Effects of linear alkylbenzene sulfonate (LAS) on the interspecific competition between Microcystis and Scenedesmus

The widespread use of detergents increases the concentration of surfactant in lakes and reservoirs. High surfactant loads produces toxicity to algae; however, the influence of the increasing surfactant on the competition between algae is not clear. In this paper, different amounts of linear alkylbenzene sulfonate (LAS) were added to test the effects of LAS on the competition between Microcystis aeruginosa and Scenedesmus obliquus under eutrophic condition. In single culture, the growth of S. obliquus was promoted under lower LAS concentrations (1 and 20mgL(-1)), but cell density of S. obliquus reduced when treated with higher LAS concentration (100mgL(-1)). The growth of M. aeruginosa was inhibited markedly with 20 and 100mgL(-1) LAS. Compared with single culture, the result was opposite in co-cultures and the cell density of S. obliquus increased significantly when treated with LAS of 1, 20, and 100mgL(-1). The specific growth rates of S. obliquus and M. aeruginosa in both cultures were 0.4-0.5day(-1) and 0.6-0.7day(-1), respectively, except that the specific growth rate of M. aeruginosa in both cultures treated with 100mgL(-1) LAS was about 0.2day(-1). M. aeruginosa dominated over S. obliquus in the co-culture without LAS, while the competition was completely opposite with the addition of 20mgL(-1) LAS. The growth of S. obliquus treated with 20mgL(-1) LAS was not affected significantly in single culture but was promoted by 75% in co-culture. Moreover, the growth of S. obliquus in co-culture treated with 100mgL(-1) LAS was promoted by more than 97%. These results suggested that the increasing LAS would overturn the competition of algae in freshwater ecosystems.

Effects of linear alkylbenzene sulfonate on the growth and toxin production of Microcystis aeruginosa isolated from Lake Dianchi.

The exogenous organic pollutant linear alkylbenzene sulfonate (LAS) pollution and Microcystis bloom are two common phenomena in eutrophic lakes, but the effects of LAS alone on Microcystis remain unclear. In the present study, we investigated the effects of LAS on the growth, photochemical efficiency, and microcystin production of Microcystis aeruginosa in the laboratory. Results showed that low LAS (≤10mg/L) concentrations improved the growth of M. aeruginosa (12days of exposure). High LAS (20mg/L) concentrations inhibited the growth of M. aeruginosa on the first 8days of exposure; afterward, growth progressed. After 12days of exposure, the concentrations of chlorophyll a in algal cells were not significantly affected by any of LAS concentrations (0.05 to 20mg/L) in the present study; by contrast, carotenoid and protein concentrations were significantly inhibited when LAS concentrations reached as high as 20mg/L. After 6 and 12days of exposure, low LAS (≤10mg/L) concentrations enhanced the maximal photochemical efficiency (Fv/Fm) and the maximal electron transport rate (ETRmax) of M. aeruginosa. Furthermore, LAS increased the microcystin production of M. aeruginosa. Extracellular and intracellular microcystin contents were significantly increased after M. aeruginosa was exposed to high LAS concentrations. Our results indicated that LAS in eutrophic lakes may increase the risk of Microcystis bloom and microcystin production.

Cytotoxic effect of linear alkylbenzene sulfonate on human intestinal Caco-2 cells: associated biomarkers for risk assessment.

Linear alkylbenzene sulfonate (LAS) is a synthetic anionic surfactant widely present in the environment due to its intensive production and use in the detergency field. Admitting that current procedure of risk assessment has limits in providing realistic risk assessment data and predicting the cumulative effect of the toxicant mixtures, the incorporation of information regarding the mode of action and cell response mechanism seems to be a potential solution to overcome these limits. In this regard, we investigated in this study the LAS cytotoxicity on human intestinal Caco-2 cells, trying to unveil the protein actors implicated in the cell response using proteomics approach in order to give a better understanding of the toxicological effect and allow the identification of appropriate biomarkers reflecting the mode of action associated with LAS. As results, we demonstrated that LAS induces a time- and dose-dependent cytotoxicity in Caco-2 cells accompanied by an induction of oxidative stress followed by an excessive increase of intracellular calcium level. Proteomics approach helped in discovering three informative biomarkers of effect associated with LAS cytotoxic effect, reported for the first time: calreticulin, thioredoxin, and heat shock cognate 71 (HSP7C), confirmed by real-time PCR and western blot analysis. These biomarkers could serve for more reliable future risk assessment studies that consider the toxicants mode of action in order to help in the prediction of potential cumulative effects of environmentally coexisting contaminants.

Histopathological changes of gill, liver and kidney in Caspian kutum exposed to Linear Alkylbenzene Sulfonate

The histopathological effects of Linear Alkylbenzene Sulfonate on the gill, liver and kidney tissues of the Caspian kutum, Rutilus frisii kutum were studied. The fish were exposed to three sublethal concentrations of anionic detergent, Linear Alkylbenzene Sulfonate (LAS) for short term intervals (192 h). Gill, liver and kidney samples were collected after 192 h of exposure to LAS and lesions were analyzed by light microscopy. The histological changes to gills were edema, fusion of lamellae and lamellar aneurism. Some alterations like reduction of the interstitial haematopoietic tissue, tubular shrinkage, degeneration in the epithelial cells of renal tubule and necrosis were observed in the kidney. In the liver tissue, hepatocyte degeneration, congestion and dilation of sinusoid and vacuolar degeneration were seen. It seems that sublethal concentration of LAS may affect sever changes to gill, kidney and liver of R. frisii kutum specimens that leads to malfunction of these organs which cause damage to health of the fish .

Influence of linear alkylbenzene sulfonate (LAS) on the structure of Alphaproteobacteria, Actinobacteria, and Acidobacteria communities in a soil microcosm

Linear alkylbenzene sulfonate (LAS) is the most used anionic surfactant in a worldwide scale and is considered a high-priority pollutant. LAS is regarded as a readily biodegradable product under aerobic conditions in aqueous media and is mostly removed in wastewater treatment plants, but an important fraction (20-25%) is immobilized in sewage sludge and persists under anoxic conditions. Due to the application of the sludge as a fertilizer, LAS reaches agricultural soil, and therefore, microbial toxicity tests have been widely used to evaluate the influence of LAS on soil microbial ecology. However, molecular-based community-level analyses have been seldom applied in studies regarding the effects of LAS on natural or engineered systems, and, to our knowledge, there are no reports of their use for such appraisals in agricultural soil. In this study, a microcosm system is used to evaluate the effects of a commercial mixture of LAS on the community structure of Alphaproteobacteria, Actinobacteria, and Acidobacteria in an agricultural soil. The microcosms consisted of agricultural soil columns (800 g) fed with sterile water (8 ml h(-1)) added of different concentration of LAS (10 or 50 mg l(-1)) for periods of time up to 21 days. Sterile water was added to control columns for comparison. The structures of Alphaproteobacteria, Actinobacteria, and Acidobacteria communities were analyzed by a cultivation independent method (temperature gradient gel electrophoresis (TGGE) separation of polymerase chain reaction (PCR)-amplified partial 16S rRNA genes). Relevant populations were identified by subsequent reamplification, DNA sequencing, and database comparisons. Cluster analysis of the TGGE fingerprints taking into consideration both the number of bands and their relative intensities revealed that the structure of the Alphaproteobacteria community was significantly changed in the presence of LAS, at both concentrations tested. The average number of bands was significantly lower in the microcosms receiving 50 mg l(-1) LAS and in the lower portion of soil cores. The clear differentiation of the samples of the upper portion of the soil columns amended with LAS was specifically related to the presence and intensity of a distinctive major band (named band class 7). There was a statistically significant positive correlation between the concentrations of LAS detected in soil portions taken from LAS 10 mg l(-1) and LAS 50 mg l(-1) microcosms and the relative intensity of band class 7 in the corresponding TGGE profiles. Prevalent Alphaproteobacteria populations in the soil microcosms had close similarity (>99%) to cultivated species affiliated to genera of the Rhizobiaceae, Methylocystaceae, Hyphomicrobiaceae, Rhodospirillaceae, Brucellaceae, Bradyrhizobiaceae, and Caulobacteraceae families. The population represented by band class 7 was found closely related to the genus Phenylobacterium (Caulobacteraceae). According to cluster analysis of TGGE profiles, the structure of both Actinobacteria and Acidobacteria communities in the soil microcosms was remarkably stable in the presence of LAS at the two concentrations tested, as most bands were universally present in all samples and displayed fairly similar relative intensities. Previous studies by others authors, based on biological and chemical tests, concluded that LAS toxicity was not an important microbial selection factor in sludge amended soil, while work based on the use of molecular fingerprinting to evaluate the impact of LAS in aqueous media and marine sediments showed that concentrations as low as 1 mg l(-1) significantly influence the development of the bacterial community structure. Although TGGE is not a strictly quantitative method due to the bias introduced by the PCR reaction, changes of band intensity through experiments are a consequence of a change in the relative abundance of the corresponding populations in the community and can be used as a semiquantitative measure of bacterial diversity. Our results evidence that the Phenylobacterium population represented by band class 7 was favored by the presence of increasing concentrations of LAS in the soil and turned into a dominant population, suggesting its possible ability to use LAS in soil as a source of nutrients. As studies with pure cultures are required to confirm the ability of this population to degrade LAS, isolation strategies are currently under development in our laboratory. The weak effect of LAS on the structure of Actinobacteria and Acidobacteria communities is particularly interesting, as to our knowledge, there are no previous reports regarding the effects of LAS on these bacterial groups in soil. CONCLUSIONS, RECOMMENDATIONS, AND PERSPECTIVES: The Phenylobacterium-related alphaproteobacterial population identified in this work was selectively enriched in LAS polluted soil and is a plausible candidate to play a relevant role in the biotransformation of the surfactant under the conditions tested. The surfactant had no remarkable effects on the Actinobacteria and Acidobacteria fingerprints in soil, even when present at concentrations widely exceeding those reached in soil immediately after sludge application. TGGE fingerprinting provides a reliable and low time-consuming method for the monitoring of the bacterial community structure and dynamics, and we recommend its integration with the biological and chemical analyses usually applied in risk assessment of LAS in the environment.

Effects of Linear Alkylbenzene Sulfonate on the Sorption of Brij 30 and Brij 35 onto Aquifer Sand

Surfactant sorption is of considerable importance to environmental applications, including surfactant flushing to mobilize hydrophobic contaminants; effects of surfactants on the transport of dissolved contaminants, microorganisms, and colloids through porous media; and bioremediation of hydrophobic organic compounds, as well as understanding the fate and transport of surfactants as environmental contaminants themselves. Although most sorption studies consider pure surfactants, commercial detergent formulations typically consist of mixtures of nonionic and anionic surfactants. In this study, the effects of varying concentrations of the anionic surfactant linear alkylbenzene sulfonate (LAS) on micelle formation and sorption behavior of the two commonly used nonionic surfactants Brij 30 and Brij 35 onto aquifer sand were examined. A strong linear relationship was observed between the critical micelle concentration (CMC) of the Brij surfactants and the concentration of LAS in the mixture, with the CMC decreasing with increasing concentration of LAS. The relative change in CMC as a function of the LAS concentration was identical forthe two Brij surfactants, indicating that LAS interacted with their common alkyl chains. Sorption isotherms were developed for Brij 30 and Brij 35 present as single surfactants in an aqueous solution as well as when present with LAS. Although LAS had minor effects on the maximum sorption plateaus of the Brij surfactants, Brij sorption at was significantly enhanced as a function of the LAS concentration for Brij aqueous concentrations below the CMC. Application of a multi-interaction isotherm model indicated that the formation of surface aggregates (e.g., hemimicelles) decreased with increasing LAS concentration. Overall, these results provide insight into the complex sorption behavior of surfactant mixtures.

Effect of Linear Alkylbenzene Sulfonate on Mortality, Hatching Rate of Eggs and Abnormality of Catfish (Pangasius hypophthalmus Sauvage) Larvae

&lt;p&gt;Linear alkylbenzene sulfonate (LAS) surfactant in the water can affecting fish in all developmental stages.  This study was aimed to observe the effect of LAS on mortality, hatching rate of eggs, and abnormality of patin catfish (&lt;em&gt;Pangasius hypophthalmus&lt;/em&gt; Sauvage) larvae.   Fertilized eggs were incubated in water containing LAS at the dosages of 0.0, 0.5, 1.5, 3.0, 9.0, and 18.0 mg/L.  Eggs mortality was observed every 6 hours until larvae hatched (24 hours).  The results of study showed that the exposure of 18.0 mg LAS per liter water could put to death all the fertilized eggs and larvae be abnormal.  The exposure of LAS at concentration of 9.0 mg/L could kill 98% of eggs and hatching rate was only 2%.  The abnormality in larvae was bending in the body and tails.&lt;/p&gt; &lt;p&gt;Keywords: patin catfish, &lt;em&gt;Pangasius&lt;/em&gt;, Linear Alkylbenzene Sulfonate, LAS, abnormality&lt;/p&gt; &lt;p&gt; &lt;/p&gt; &lt;p&gt;ABSTRAK&lt;/p&gt; &lt;p&gt;Surfaktan &lt;em&gt;Linear Alkylbenzene Sulfonate&lt;/em&gt; (LAS) yang masuk ke dalam perairan sangat berpengaruh terhadap ikan dari stadia awal hidup ikan sampai dewasa. Penelitian ini bertujuan untuk mengetahui pengaruh LAS terhadap mortalitas, daya tetas telur dan abnormalitas larva ikan patin (&lt;em&gt;Pangasius hypophthalmus&lt;/em&gt; Sauvage).  Telur ikan patin yang telah dibuahi di rendam dalam air yang mengandung LAS dengan konsentrasi 0,0; 0,5; 1,5; 3,0; 9,0 dan 18,0 mg/L.  Mortalitas telur dicatat setiap 6 jam sampai menetas (24 jam).  Hasil penelitian menunjukkan bahwa konsentrasi LAS sebesar 18,0 mg/L dapat mengakibatkan mortalitas telur dan abnormalitas pada larva secara total.  Konsentrasi LAS sebesar 9,0 mg/L dapat mematikan telur hingga 98% dan hanya menghasilkan daya tetas sebanyak 2%. Abnormalitas pada larva berupa pembengkokan pada tubuh dan ekor.&lt;/p&gt; &lt;p&gt;Kata kunci: ikan patin, &lt;em&gt;Pangasius&lt;/em&gt;, &lt;em&gt;Linear Alkylbenzene Sulfonate&lt;/em&gt;, LAS dan abnormalitas&lt;/p&gt;

Effects of Linear Alkylbenzene Sulfonates (LASs) in Sewage Sludge–Amended Soils on Nutrient Contents of Broccoli Plants

Sewage sludge is used in agriculture as a fertilizer and an organic amendment to improve physical and chemical soil properties. However, sludge contains organic compounds, such as surfactants, which may be toxic in the soil–plant system. The effects on plants of linear alkylbenzene sulfonates (LAS), a group of anionic surfactants that are widely used in detergent products, have not been well defined. In this experiment, the effect of differently treated sewage sludge containing LAS on the macronutrient and sodium contents of different parts of broccoli plants (Brassica oleracea L. var. botrytis subvar. cymosa Lam.) was studied in a field experiment. Fertilizer treatments were un‐composted sewage sludge (UCSS), composted sewage sludge (CSS), and a control without fertilization (NF). The LAS levels were established across all fertilizer treatments by addition of 0, 15, or 30 g LAS m−2 (LAS0, LAS15, and LAS30, respectively). In general, the macronutrient contents in shoots, leaves, and edible parts of broccoli were higher in plants cultivated without fertilization but with LAS. In most cases, the LAS application increased the nitrogen, phosphorus, and sodium contents of the different plant parts, whereas calcium and magnesium concentrations were reduced.

Effect of linear alkylbenzene sulphonate (LAS) on the mineralization, metabolism and uptake of 14C-phenanthrene in a model ecosystem (water–lava–plant–air)

The aim of this work was to evaluate the effect of linear alkylbenzene sulfonate (LAS, 200 mg l −1) on the fate of phenanthrene in a model ecosystem “water–lava–hydrophytes–air”. The experiments were conducted using two closed cultivation chamber systems. Rushes ( Juncus effesus) were selected as a representative hydrophyte. Five hundred micrograms per liter of phenanthrene in a culture solution containing a 14C-activity of 75 μCi per chamber was applied (i) to investigate the degradation of the labeled test substance and the transfer processes within the system; (ii) to determine the mass-balance possible and (iii) to detect the occurrence of volatile test substances, their volatile metabolites and the degradation end-product CO 2 in the gas phase. Most of the applied 14C-activity was found in the plant (41–45%), in which ≈95% was associated with plant roots and ≈5% with shoots. The 14C-activity recovered in the form of VOCs and CO 2 was measured in lava (18–29%, 8–11%), and in the culture solution (10–14% and 1%), respectively. Majority of the applied 14C-activity existed in two forms, i.e. (1) polar metabolites (26%), of which 91% were found in plant roots, and (2) un-extractable residues (23%), most of which were in plant roots (40%) and bounded to lava (58%). The presence of LAS significantly increased the volatilization of phenanthrene and its metabolites, inhibited its mineralization and decreased the level of 14C-activity in lava. Moreover, LAS reduced the phenanthrene level in plant roots.

Effect of linear alkylbenzene sulfonate (LAS) on ion transport and intracellular calcium in kidney distal epithelial cells (A6)

Linear alkylbenzene sulfonate (LAS) is found in near-shore environments receiving wastewater from urban treatment plants in a concentration reported to have physiological and toxic effect on aquatic organisms. The aim of this study was to investigate the effect LAS on ion transport and homeostasis in epithelia cells. A6 cells form a polarised epithelium when grown on permeable supports, actively absorb sodium and secrete chloride. Only the addition of LAS (100 μ m) to the apical solution of A6 epithelia resulted in an increase in the active ion transport measured as short circuit current (SCC) and transepithelial conductance (G t). This increase could not be affected by the sodium channel inhibitor amiloride (100 μ m), indicating that LAS stimulated the chloride secretion. Change in the intracellular calcium concentration (Ca 2+) i was measured in fura-2 loaded A6 cells, since it known that increase in (Ca 2+) i stimulate chloride secretion. LAS induced a concentration-dependent increase in (Ca 2+) i from 5 to 200 μ m, where the half-maximal stimulating concentration on 100 m m resulted in an increase in (Ca 2+) i from 108±15 to 570±26 n m ( n=4; P<0.01). The increase in (Ca 2+) i could be blocked by the calcium chelator ethylenebis(5-oxyethylenenitrilo)tetraacetic acid (EGTA), showing that the effect of LAS was due to influx of extracellular calcium. Furthermore, it was shown that the calcium channel inhibitor verapamil (0.2 m m) abolished the LAS induced increase in (Ca 2+) i and Gt when applied to the apical solution. However, verapamil has no inhibitory effect on these parameters when the non-ionic detergent Triton X-100 (100 μ m) was added to A6 cells. These results indicate that LAS induced a specific activation of calcium channels in the apical membrane of A6 epithelia, leading to increase in (Ca 2+) i and thereby increased chloride secretion as a result of stimulation of calcium-dependent chloride channels in the apical membrane. The change in ion homeostasis is thought to be the fundamental reason to the physiological and toxic effects induced by LAS in marine organism.