Exposure of the marine deposit feeder Hydrobia ulvae to sediment spiked with LAS congeners

The lethal and sub-lethal toxicity of LAS congeners to the mollusc gastropod Hydrobia ulvae were assessed in spiked sediment bioassays. This complements the little knowledge available to date on mixture effects in the sediment compartment. The LAS homologues joint effect was concentration additive (∑TU_i = 0.8-1). As opposed to the 10-d LC10 based on the sediment associated LAS concentration (91-330 mg/kg) which was independent of the homologue chain length, the LC10 based on the dissolved LAS fraction (0.804-0.068 mg/L) decreased as the homologue chain length increased from 10 to 13 carbons. The quantitative structure-activity relationship (QSAR) derived from these data was log (1/LC10 (mol/L)) = 0.64 log K_ow + 4.40 (n = 5; r² = 0.76; s = 0.24). It showed an apparent higher toxicity compared to the typical QSAR for polar narcosis in water-only systems probably due to the simultaneous exposure of the snail to LAS through the dissolved and the sediment associated fractions. The egestion rate of the surviving snails recovered after few days' exposure (1-d NOEC: 40-107 mg/kg, 9-d NOEC: 65-190 mg/kg) which suggests that the organisms were able to acclimate to LAS during the exposure.     

Occurrence and fate of linear and branched alkylbenzenesulfonates and their metabolites in surface waters in the Philippines

Laguna de Bay in the Philippines is one of the largest freshwater lakes in Asia and is considered a primary source of drinking water, but also receives daily discharges of effluent from both domestic and industrial activities. Branched alkylbenzenesulfonates (ABS), which were banned in Europe and withdrawn from the market in the U.S. since the mid-1960s, but not in Southeast Asia, and linear alkylbenzenesulfonates (LAS) are anionic surfactants used in detergent formulations and are therefore main components of effluent discharges. The presence of both LAS and ABS in several water streams in the catchment area of Laguna de Bay was determined using liquid chromatography-mass spectrometry (LC-MS). The concentration levels of LAS (1.2-73 and 2.2-102 microg l(-1)) and ABS (1.1-75 and 1-66 microg l(-1)) in some tributaries of Laguna de Bay and its outlet (Pasig River) to Manila Bay were assessed in December 1999 and March 2000, respectively. The LAS/ABS ratio was calculated as an indication of the extent of the distribution and fate of these surfactants in the surface water. The nearer the location to the metropolitan area of Manila, the higher the levels of LAS and ABS detected in the waters. Moreover, the extent of biodegradation was investigated by monitoring their alkyl homologue distribution and the presence of sulfophenylcarboxylate (SPC) metabolites. Similarly, differences in the levels of SPC and the homologues were apparent at the different sampling points. Presumably, even the quite recalcitrant ABS form SPCs under the conditions present in Southeast Asia. Since wastewater treatment facilities are not well established in developing countries like the Philippines, the call for the use of environmentally friendly chemicals is of even higher significance.     

Reduction of aquatic toxicity of linear alkylbenzene sulfonate (LAS) by biodegradation

Partial biodegradation of LAS is shown to significantly reduce the specific toxicity (i.e. per unit weight) of the remaining LAS to Daphnia magna (water fleas) and Pimephales promelas (fathead minnows). This results from the fact that the longer homologs and more terminal isomers, which are the more toxic, are also the more rapidly degraded under bacterial action. The acute aquatic LC₅₀ of LAS may range from 0.5 to 50 mg/l depending mainly upon the chain length of the particular homolog. A high molecular weight commercial type LAS with LC₅₀ around 2 mg/l before biodegradation may show Daphnia LC₅₀'s of 30–40 mg/l. for the LAS remaining after 80–85% degradation.A further contribution to this toxicity reduction may occur if the methylene blue analytical method is used to determine the amount of LAS remaining, since some of the biodegradation intermediates show methylene blue activity but no significant toxicity. For example, sulfophenylundecanoate, a model of early intermediates, shows Daphnia and fathead lc₅₀'s 200 and 75 mg/l., respectively. Sulfophenylbutyrate, modeling somewhat later intermediates, gives lc₅₀ values around 5000–10,000 mg/l. Dialkyl tetralin/indane sulfonates (the major non-linear components in commercial LAS) exhibit 1/2–1/10 the toxicity of the corresponding LAS homologs.These results re-emphasize that analysis simply for methylene blue active substances (MBAS) gives no basis for predicting the aquatic toxicity of an environmental sample. And furthermore, that meaningful water quality criteria and standards cannot be established in terms of MBAS content while based on toxicity studies on intact, undegraded LAS.     

Toxicity characterization of urban stormwater with bioanalytical tools

Stormwater harvesting has become an attractive alternative strategy to address the rising demand for urban water supply due to limited water sources and population growth. Nevertheless, urban stormwater is also a major source of surface water pollution. Runoff from different urban catchments with source contributions from anthropogenic activities and various land uses causes variable contaminant profiles, thus posing a challenging task for environmental monitoring and risk assessment. A thorough understanding of raw stormwater quality is essential to develop appropriate treatment facilities for potential indirect potable reuse of stormwater. While some of the key chemical components have previously been characterized, only scarce data are available on stormwater toxicity. We benchmarked stormwater samples from urban, residential and industrial sites across various Australian capital cities against samples from the entire water cycle, from sewage to drinking water. Six biological endpoints, targeting groups of chemicals with modes of toxic action of particular relevance for human and environmental health, were investigated: non-specific toxicity (Microtox and combined algae test), the specific modes of action of phytotoxicity (combined algae test), dioxin-like activity (AhR-CAFLUX), and estrogenicity (E-SCREEN), as well as reactive toxicity encompassing genotoxicity (umuC) and oxidative stress (AREc32). Non-specific toxicity was highly variable across sites. The baseline toxicity equivalent concentrations of the most polluted samples were similar to secondary treated effluent from wastewater treatment plants. Phytotoxicity results correlated well with the measured herbicide concentrations at all sites. High estrogenicity was found in two sampling events and could be related to sewage overflow. Genotoxicity, dioxin-like activity, and oxidative stress response were evident in only three of the samples where the stormwater drain was beside a heavy traffic road, confirming that road runoff is the potential source of contaminants, while the bioanalytical equivalent concentrations (BEQ) of these samples were similar to those of raw sewage. This study demonstrates the benefit of bioanalytical tools for screening-level stormwater quality assessment, forming the basis for the evaluation of future stormwater treatment and reuse schemes.     

Influence of the hydrophilic moiety of anionic and nonionic surfactants on their aerobic biodegradation in seawater

The extent and kinetics of the primary biodegradation have been characterized for the most commonly-used surfactants, employing four homologues with the same alkyl chain: dodecyl ethoxy sulfate (C₁₂AES), sodium dodecyl sulfate (SDS), dodecyl alcohol ethoxylate (C₁₂AEO) and dodecyl benzenesulfonate (C₁₂LAS). A brief acclimatization period has been required to enable an effective degradation of C₁₂LAS and C₁₂AES to take place, but this lag phase has not been detected for SDS and C₁₂AEO. Primary biodegradation percentages at the end of these experiments were higher than 99%, showing a fast degradation rate in all cases (average half-life lower than 2 days). The secondary biodegradation of C₁₂LAS was also monitored. C₁₂LAS external isomers, which are predominant, are preferentially degraded by successive β-oxidations, generating significant amounts of external even isomers of sulfophenylcarboxylic acid (SPC) (mainly 2,3ΦC_4,6SPCs). In ontrast, internal isomers are converted into internal odd isomers of SPC (mostly 4,5ΦC_5,7SPCs) by ω-oxidation followed by α-oxidation and/or β-oxidations.     

Interactions between toxic chemicals and natural environmental factors — A meta-analysis and case studies

The paper addresses problems arising from effects of natural environmental factors on toxicity of pollutants to organisms. Most studies on interactions between toxicants and natural factors, including those completed in the EU project NoMiracle (Novel Methods for Integrated Risk Assessment of Cumulative Stressors in Europe) described herein, showed that effects of toxic chemicals on organisms can differ vastly depending purely on external conditions. We compiled data from 61 studies on effects of temperature, moisture and dissolved oxygen on toxicity of a range of chemicals representing pesticides, polycyclic aromatic hydrocarbons, plant protection products of bacterial origin and trace metals. In 62.3% cases significant interactions (p ≤ 0.05 or less) between natural factors and chemicals were found, reaching 100% for the effect of dissolved oxygen on toxicity of waterborne chemicals. The meta-analysis of the 61 studies showed that the null hypothesis assuming no interactions between toxic chemicals and natural environmental factors should be rejected at p = 2.7 × 10^− 82 (truncated product method probability). In a few cases of more complex experimental designs, also second-order interactions were found, indicating that natural factors can modify interactions among chemicals. Such data emphasize the necessity of including information on natural factors and their variation in time and across geographic regions in ecological risk assessment. This can be done only if appropriate ecotoxicological test designs are used, in which test organisms are exposed to toxicants at a range of environmental conditions. We advocate designing such tests for the second-tier ecological risk assessment procedures.     

Genes and environment - striking the fine balance between sophisticated biomonitoring and true functional environmental genomics

This article provides an overview how the application of the gene profiling (mainly via microarray technology) can be used in different organisms to address issues of environmental importance. Only recently, environmental sciences, including ecotoxicology, and molecular biology have started to mutually fertilize each other. This conceptual blend has enabled the identification of the interaction between molecular events and whole animal and population responses. Likewise, striking the fine balance between biomonitoring and functional environmental genomics will allow legislative and administrative measures to be based on a more robust platform. The application of DNA microarrays to ecotoxicogenomics links ecotoxicological effects of exposure with expression profiles of several thousand genes. The gene expression profiles are altered during toxicity, as either a direct or indirect result of toxicant exposure and the comparison of numerous specific expression profiles facilitates the differentiation between intoxication and true responses to environmental stressors. Furthermore, the application of microarrays provides the means to identify complex pathways and strategies that an exposed organism applies in response to environmental stressors. This review will present evidence that the widespread phenomenon of hormesis has a genetic basis that goes beyond an adaptive response. Some more practical advantages emerge: the toxicological assessment of complex mixtures, such as effluents or sediments, as well as drugs seems feasible, especially when classical ecotoxicological tests have failed. The review of available information demonstrates the advantages of microarray application to environmental issues spanning from bacteria, over algae and spermatophytes, to invertebrates (nematode Caenorhabditis elegans, crustacea Daphnia spp., earthworms), and various fish species. Microarrays have also highlighted why populations of a given species respond differently to similar contaminations. Furthermore, this review points at inherent limits of microarrays which may not yet have been properly addressed, namely epigenetics, which may explain heritable variation observed in natural population that cannot be explained by differences in the DNA sequence. Finally, the review will address promising future molecular biological developments which may supersede the microarray technique.     

Fate and effects of linear alkylbenzene sulphonates (LAS) in the terrestrial environment

Linear alkylbenzene sulphonates (LAS) are a group of anionic surfactants, characterised by having both a hydrophobic and a hydrophilic group. LAS is one of the major ingredients of synthetic detergents and surfactants and is used world-wide for both domestic and industrial applications. LAS is relatively rapidly aerobically degraded, but only very slowly or not at all degraded under anaerobic conditions. Therefore, LAS can be found in very high concentrations in most sewage sludge and enter the soil compartment as a result of sludge application. LAS can be found in elevated concentrations in soil immediately after sludge amendment, but a half-life of approximately 1-3 weeks will generally prevent accumulation in soil and biota. The concentration in soils that have not received sewage sludge recently, is generally less than 1 mg kg-1 and not more than 5 mg LAS kg-1. This is below the lowest concentration of LAS where effects have been observed in the laboratory. The laboratory data is in accordance with field studies using aqueous solutions of the sodium salt of LAS. However, observations of the ecological impact of sewage sludge applications or application of LAS spiked into sludge indicates a lower toxicity of LAS when applied in sludge. On the basis of the information reviewed in this paper, it is concluded that LAS can be found in high concentrations in sewage sludge, but that the relatively rapid aerobic degradation and the reduced bioavailability when applied via sludge, most likely will prevent LAS from posing a threat to terrestrial ecosystems on a long term basis.     

Levels Of Linear Alkylbenzenesulfonates (LAS) In Sediments Of The Berre Lagoon (FRANCE)

A method is described to extract, concentrate and determine trace levels of linear alkylbenzenesulfonates (LAS) (a major anionic surfactant) from sediment samples. It consists of an ultrasonic extraction, followed by clean up and enrichment with C18 mini-columns cartridges and determination by HPLC. Both efficiency and accuracy of the method are high, i.e. mean recovery of 85% and repeatability of 2.8% relative standard deviation for five-replicate LAS analyses. The spatial distribution of LAS and their composition of homologues in sediments of the Berre lagoon, the widest lagoon of the Mediterranean littoral, have been studied. The levels of total LAS in sediments range from 0.21 to 5.00?mg=g (dry weight). Results show that LAS principally associated with solids in suspension, and originating from industrial and urban wastewaters, are principally discharged into the Arc and Cadière Rivers then decant in the mouths of these rivers. The maximum concentrations have been monitored in three zones of the site: the Bolmon lagoon, the Vaine lagoon and the northeast part of the Berre lagoon. The distribution of the LAS homologues in the sediments is not the same as that of the commercial LAS. A great percentage of C13-LAS has been observed (>50%).     

The combined toxic effects of nonpolar narcotic chemicals to Pseudokirchneriella subcapitata

This paper presents the toxicity data of 10 nonpolar narcotic chemicals on Pseudokirchneriella subcapitata (green algae) assessed by a new algal toxicity testing technique conducted under air-tight environment. Based on DO production, median effective concentration (EC50) varies from 1.73 mg/L (1-octanol) to 8,040 mg/L (2-propanol). The endpoint of algal growth rate reveals similar sensitivity as that from DO production. Compared to literature data, Pseudokirchneriella subcapitata and Nitrosomonas are apparently more sensitive to nonpolar narcotics than other organisms such as minnow, daphnia, and Tetrahymena pyriformis. Furthermore, good correlations between toxic effects observed from Pseudokirchneriella subcapitata and other aquatic organisms were found. Hence, algal toxicity test can be considered as a surrogate test for estimating the toxicity of nonpolar chemicals to fathead minnow, Microtox, activated sludge, Daphina magna, and Tetrahymena pyriformis. The combined effects of 13 binary mixtures of nonpolar chemicals were investigated using both additive-index method and isobologram analysis. Overall speaking, the joint actions between these chemicals are strictly additive. Model analyses indicate that these compounds act on identical reaction sites or receptors, which verify that these chemicals are of the same toxicity mechanism (narcosis).     

The behaviour of linear alkyl benzene sulphonate under direct discharge conditions in Vientiane, Lao PDR

Direct discharge of untreated sewage to surface waters is a common practice in many parts of the world. However, relatively little is known about the behaviour of synthetic organic pollutants under these conditions. This paper describes a sampling campaign designed to track changes in water quality in a surface water system in Vientiane (Lao PDR) receiving significant quantities of untreated waste water. The study was based on following in-channel transport using a fluorescent tracer injected as a pulse, with a focus on the anionic surfactant linear alkylbenzene sulphonate (LAS) and ammonia. Water samples were collected at a number of stations with sampling times estimated to coincide with solute time-of-travel. The reduction in LAS concentration with flow-time could be approximated by first-order kinetics with a half life of about 7 h. Free ammonia concentrations decreased more slowly than LAS and remained above the level believed to be toxic for sensitive aquatic species along the entire channel. Changes in the ratios of LAS alkyl chain homologues to total LAS concentrations suggest a preferential removal of longer chain lengths. The role of biodegradation in the removal of LAS was confirmed by the presence of LAS metabolites (sulphophenylcarboxylates, SPCs) which increased systematically (as a fraction of LAS remaining) with flow-time.     

Carcinogenicity testing of chemicals with particular reference to organochlorine pesticides.

The organochlorine chemicals comprise a large number of pesticides that are used widely throughout the world. The organochlorine pesticides given in the diet to mice are carcinogenic for the liver. They induce not only carcinomas of the liver, particularly at the higher doses, but also carcinomas and sarcomas in other organs in rats. They cause acute and chronic liver and kidney injury, which interferes with the development of carcinomas and sarcomas in rats. The testing of chemicals for carcinogenicity, with particular reference to organochlorine pesticides, includes discussions on the following topics: classification of hepatic lesions in mice and rats, toxicity versus carcinogenicity in the testing of chemicals, a comparison of carcinomas and cirrhosis of the liver in experimental animals and humans, and the significance of laboratory carcinogenicity findings to human health.     

Georeferenced aquatic fate simulation of cleaning agent and detergent ingredients in the river Rur catchment (Germany)

The Geography-referenced regional exposure assessment tool for European rivers (GREAT-ER) 1.0 was developed in the context of environmental risk assessment of chemicals to calculate the aquatic fate of 'down-the-drain' chemicals in surface waters due to point release. As a follow-up project, the river Rur catchment in Germany was incorporated into the system. This included aspects of data collection, modelling and monitoring. Investigated substances are the four detergent and cleaning agent ingredients boron, linear alkylbenzene sulfonate (LAS), nitrilotriacetate (NTA) and ethylenediaminetetraacetate (EDTA). Results of the catchment's incorporation into the system and a comparison of GREAT-ER simulations with different monitoring results are both given. It is shown that data sets derived from a literature review can be used to calculate concentration profiles that are in the range of measured values. Since the model establishes a causal relationship between emission sites and data on the one hand, and observed concentrations in the receiving surface waters on the other, the simulation results can be used to explain monitoring data.     

Measured concentrations of consumer product chemicals in California house dust: Implications for sources,exposure, and toxicity potential

Household dust is a reservoir of various consumer product chemicals. Thus, characterizing comprehensive chemical profiles of house dust may help improve our understanding of residential chemical exposure. We have previously developed a method for detecting a broad spectrum of chemicals in dust by applying a combination of target, suspect screening, and non-target methods with mass spectrometry preceded by liquid chromatography and gas chromatography. Building upon a previous study that detected 271 compounds in 38 dust samples, we presented concentrations of 144 compounds that were confirmed and quantified by standards in the same set of samples. Ten compounds were measured with median concentrations greater than 10 000 ng/g of dust: cis-hexadec-6-enoic acid, squalene, cholesterol, vitamin E, bis(2-ethylhexyl) phthalate, dioctyl terephthalate, linoleic acid, tricaprylin, tris(1-chloroisopropyl) phosphate, and oxybenzone. We also reviewed in vitro toxicity screening data to identify compounds that were not previously detected in indoor dust but have potential for adverse health effects. Among 119 newly detected compounds, 13 had endocrine-disrupting potential and 7 had neurotoxic potential. Toxicity screening data were not available for eight biocides, which may adversely affect health. Our results strive to provide more comprehensive chemical profiles of house dust and identified information gaps for future health studies.     

Selection and evaluation of adsorbents for the removal of anionic surfactants from laundry rinsing water

Low-cost adsorbents were tested to remove anionic surfactants from laundry rinsing water to allow re-use of water. Adsorbents were selected corresponding to the different surfactant adsorption mechanisms. Equilibrium adsorption studies of linear alkyl benzene sulfonate (LAS) show that ionic interaction results in a high maximum adsorption capacity on positively charged adsorbents of 0.6-1.7 gLAS/g. Non-ionic interactions, such as hydrophobic interactions of LAS with non-ionic resins or activated carbons, result in a lower adsorption capacity of 0.02-0.6 gLAS/g. Negatively charged materials, such as cation exchange resins or bentonite clay, have negligible adsorption capacities for LAS. Similar results are obtained for alpha olefin sulfonate (AOS). Cost comparison of different adsorbents shows that an inorganic anion exchange material (layered double hydroxide) and activated carbons are the most cost-effective materials in terms of the amount of surfactant adsorbed per dollar worth of adsorbent.     

Effect of linear alkylbenzene sulphonates (LAS) on the anaerobic digestion of sewage sludge

Batch anaerobic biodegradation tests with different alkylbenzene sulphonates (LAS) at increasing concentrations were performed in order to investigate the effect of LAS homologues on the anaerobic digestion process of sewage sludge. Addition of LAS homologues to the anaerobic digesters increased the biogas production at surfactant concentrations 5-10 g/kg dry sludge and gave rise to a partial or total inhibition of the methanogenic activity at higher surfactant loads. Therefore, at the usual LAS concentration range in sewage sludge, no adverse effects on the anaerobic digesters functioning of a wastewater treatment plant (WWTP) can be expected. The increase of biogas production at low surfactant concentrations was attributed to an increase of the bioavailability and subsequent biodegradation of organic pollutants associated with the sludge, promoted by the surfactant adsorption at the solid/liquid interface. When the available surfactant fraction in the aqueous phase instead of the nominal surfactant concentration was used to evaluate the toxicity of LAS homologues, a highly significant relationship between toxicity and alkyl chain length was obtained. Taking into account the homologue distribution of commercial LAS in the liquid phase of the anaerobic digesters of a WWTP, an EC(50) value of 14 mg/L can be considered for LAS toxicity on the anaerobic microorganisms.     

动物蛋白类混凝士发泡剂的制备与发泡性能测试

以氢氧化钠、盐酸和人发为主要原料制备XK型动物蛋白混凝土发泡剂,以十二烷基苯磺酸钠(LAS)、十二烷基硫酸钠(SDS)和明胶3种稳泡剂对合成发泡剂进行复配改性,并对复配发泡剂的稳泡性能进行了分析研究。结果表明,这3种稳泡剂能不同程度提高合成发泡剂的泡沫稳定性,其中以LAS与明胶复配的改性作用最好。     

Effect of laundry activities on in-stream concentrations of linear alkylbenzene sulfonate in a small rural South African river

In many parts of the world clothes are washed near to or in rivers and streams. Little information is available on resulting concentrations of detergent ingredients or on any potential effects caused. In this study, the fate of a commonly used anionic surfactant, linear alkylbenzene sulphonate (LAS) was investigated in a reach of the Balfour River (Eastern Cape Province, South Africa) which was regularly used as a site for laundry activity. Samples of river water were collected upstream of the main washing site and at a number of locations downstream on several occasions in winter and summer. Sediment samples were also collected and analysed. In addition, a household survey was conducted to ascertain the amount of detergent used and the distribution of washing practices. The results of the survey suggested that the use of riverside locations for laundry activities was seasonal. Most washing tended to be done at home during the winter with riverside sites used more frequently during the summer months. The monitoring data showed that LAS concentrations in water were very variable. They were occasionally high in the immediate vicinity of the laundry site (up to 342 µg L^− 1) but were generally very low (< 11 µg L^− 1) at downstream monitoring stations, suggesting that LAS was rapidly dissipated by a combination of degradation, hydrodynamic dispersion and dilution. Concentrations in the immediate vicinity of the washing site were lower than expected on the basis of the household survey because most waste water was disposed of on the river bank rather than directly in the river. No ecological effects are expected from LAS emissions at this site.