Background Surfactants are widely used across the globe both in industrial and consumer products; their biodegradation characteristics are therefore of high importance. Upon entering a wastewater treatment plant (WWTP), the majority of surfactants are aerobically mineralized to CO 2 and H 2 O. However, a small fraction is inevitably left non-degraded and adheres to the remaining sludge. This sludge is usually further treated in anaerobic digester tanks. Assessment of existing methods for determining anaerobic biodegradability has led to the development of a new test method, which is in principle based on the method DIN 38414 part 8. This new test, named the anaerobic biodegradation under sludge digester conditions test (abbreviated to AnBUSDiC test) allows for a quantification of the degradation of surfactants under conditions encountered in the anaerobic digester tank of municipal WWTPs. The AnBUSDiC test has several advantages over existing methods. The main advantage is that it is particularly suitable for surfactants, because the two-step design minimizes possible unspecific digester gas formation caused by the surface activity of the test substances, therefore avoiding false positive results. Results In order to further standardize the AnBUSDiC test and gain regulatory acceptance, a ring test was organized involving seven laboratories, and five model surfactants from different surfactant classes (anionic, non-ionic (branched and linear) and amphoteric) plus a positive control, glucose. The AnBUSDiC test produced reliable repeatable results between laboratories; however, some additional modifications were suggested. It was identified that the original test method did not identify a clear endpoint from which a biodegradation value should be taken. It was proposed that a new more concise endpoint be defined in combination with the AnBUSDiC test to allow better comparability between test results. Conclusions The inclusion of a second addition of test substance is a major step forward in the elimination of the variability produced by non-specific gas production. With the exception of one anomalous result for linear alkylbenzene sulfonates, for which an explanation can be provided, the AnBUSDiC method appears to provide overall robust and interpretable results.

A new analytical procedure for the determination of alcohol ethoxylates (AE) in environmental samples such as influents, effluents and sludge from waste water treatment plants (WWTPs) was developed. Although some work had been previously published on the detection of AE in water samples, this is the first paper that deals with AE in sludge. Alcohol ethoxylates were removed from water samples by sorption on polymeric discs followed by extraction with methanol. The methanol extracts were cleaned up with two alumina solid-phase extractions (SPE) at different conditions of solvent polarity, one before and the other after derivatization with naphthoyl chloride. A final polishing step was carried out on a Florisil SPE column. Liquid chromatography/mass spectrometry with electrospray ionization was used to quantify AE as naphthoyl derivatives. The detection limits for AE ethoxymers range from 0.07 to 0.005 μg/L in water samples. The method was applied to an Italian WWTP in order to follow the fate of AE during treatment, AE concentrations of 839 μg/L, 0.46 μg/L and 10.6 mg/kg were respectively found in the inlet, outlet and sludge samples. AE removals of each ethoxymer in the plant were in the range 99.6–100% and no difference was observed between high or low-mole ethoxymers and between AE with odd or even carbon chain lengths. An overall 99.7% removal was also determined on the mass balance of AE in the inlet, the outlet, and sludge of the plant.

To obtain robust data on the toxicity of LAS, tests with the collembolan Folsomia candida L., the oligochaetes Aporrectodea caliginosa Savigny (earthworm) and Enchytraeus crypticus Westheide and Graefe (enchytraeid) were performed in a sandy loam soil. Additionally limited tests with LAS spiked to sewage sludge, and subsequently mixed into soil, were performed. For the endpoint of interest, reproduction in soil, we found an EC10 of 205 mg LAS kg−1 soil [8.6–401] [95% confidence limits] for F. candida and an EC10 of 46 mg LAS kg−1 soil [13–80] for A. caliginosa after 28 days. E. crypticus was not affected by concentrations up to 120 mg LAS kg−1 soil. When adding (low contaminated) non-spiked sludge to soil, high stimulation of reproduction was observed for E. crypticus and A. caliginosa but not for F. candida. We argue that this difference in stimulative response between the tested species is related to the difference in feeding behaviour. Sludge spiked with LAS did not significantly affect the reproduction of F. candida (fertility: number of juvenile offspring) and A. caliginosa (fecundity: number of cocoons) (dose equivalent to 181 g and 91 g LAS kg−1 sludge, respectively). Significantly reduced reproduction was observed for E. crypticus (at 120 mg LAS kg−1 soil + sludge corresponding to 72 g LAS kg−1 sludge) compared to non-spiked sludge. The reproduction by E. crypticus was, however, comparable to the reproduction observed in the control soil without sludge. Compared to LAS directly spiked to soil, the reproductive output of organisms exposed to spiked sludge was either not significantly different (F. candida, E. crypticus) or significantly improved (A. caliginosa). More studies are needed in order to make firm conclusions on the potential effect of artificially contaminated sludge in soil systems.

VASELINE oil intoxication is a known cause of exogenous lipoid pneumonia. 1 Vaseline oil is a mixture of saturated aliphatic (C14-C18) and cyclic hydrocarbons 2 that is insoluble in water and, in the alveolar space, activates an acute inflammatory response with edema and interstitial fibrosis. 3 Because the hydrocarbons cannot be metabolized in humans, the therapy consists of limiting or decreasing the inflammatory reaction by steroids or of removing the hydrocarbons. The success of the two approaches depends on the extent of the intoxication, but unfortunately, no quantitative measurements of hydrocarbons are available in the literature. We report a case in which we quantitatively assessed the hydrocarbon lung concentrations during treatment.

The characterization of alcohol ethoxylates (AE) has been approached in our laboratory for many years. Both Atmospheric Pressure Chemical Ionization (APCI) and Electro Spray Ionization (ESI) Mass Spectrometry techniques have been used with pure mid derivatized AE. The APCI technique revealed the problem of low sensitivity for lower ethoxymers and showed some thermal degradation with some types of derivatized AE. Better results were obtained with LC-MS in ESI mode with non-derivatized AE but free alcohol and low ethoxymers were again lost because of low sensitivity The outcome of all Our approaches to have reliable and accurate EO distributions, was to convert alcohol ethoxylates into alcohol ethoxy sulfates (AFS) followed by LC-MS analysis in ESI negative ion mode. The mass spectra of AS and AES present only R-OSO3- ions and all ethoxymers have almost the same molar response, indicating that their responses do not depend on the number of ethoxy units as in the case of underivatized AE. This fact would exclude the need for correcting the response factors with a calibrated standard. This analytical approach was shown to be very helpful in affording full EO distribution of AE and it was shown to be applicable also to propoxylates and to EO-PO copolymers.

A new analytical method was developed for the routine specific determination of the anionic surfactant Alcohol polyEthoxylate Sulfate (AES) in environmental aqueous samples. An enrichment/fractionation of the target analytes in water samples was performed by solid-phase extraction (SPE) on graphitized carbon black (GCB) (recoveries: 90-103%), followed by hydrolysis/derivatization with fluorescent reagents and separation/detection by reversed-phase high performance liquid chromatography coupled with fluorescence (HPLC-FLD). The developed procedure was applied to the study of the aerobic biodegradation of AES under laboratory conditions and to a ten-month monitoring of AES, as well as of linear alkylbenzene sulfonates (LAS), nonylphenol polyethoxylates (NPE) and alcohol polyethoxylates (AE) surfactants, in the Po river (Northern Italy). The residual concentrations found in the river waters were compared and used for a preliminary estimation of the annual average loads of monitored surfactants in the Adriatic Sea.

The characterization of alcohol ethoxylates (AE) to determine ethylene oxide (EO) adduct distribution has been studied in our laboratory for many years by using high-performance liquid chromatography-mass spectrometry (LC-MS). This paper describes the LC-MS approach being used to analyze both nonderivatized and derivatized AE. We conclude that the best way to determine EO adduct distribution is by first converting the AE to alcohol ethoxy sulfates (AES) and then by using LC-MS with electrospray ionization in the negative ion mode. A convenient laboratory technique for converting small-scale samples of AE to AES has been discovered and is reported herein. Several examples of EO adduct distribution determined by this method are presented for both linear and isomeric AE samples.

Derivatization of a C 12 Φ-methyl ester sulfonic acid by using iodide-trifluoroacetic anhydride in dimethylformamide in a one-step reaction yielded derivatized sulfonic thiotrifluoroacetates. The latter have been analyzed by gas chromatography-mass spectrometry (MS) and liquid chromatography-MS techniques so that, for the first time, the acid composition and the mono sulfonic acid isomer distribution are shown.

Aerobic biodegradation of the 2-butyl-octyl alcohol polyethoxylate (2Bu-C(8)AE) was investigated under laboratory standardized conditions (Organization for Economic Cooperation and Development 301E and 310B screening test protocols) to study the effect of the 2-alkyl chain length on the biodegradation mechanism of monobranched alcohol polyethoxylates (AEs). The 2Bu-C(8)AE was compared with linear and monobranched AEs with short 2-alkyl chains, which were simultaneously tested under the same inoculum conditions. The metabolites identified and the primary biodegradation rate constants obtained indicate that the alkyl chain length of the 2-alkyl substituent is the factor governing the biodegradation pathway of monobranched AEs. Short 2-alkyl substituents (i.e., methyl and ethyl groups) allow the central cleavage mechanism to occur, which leads to the formation of polyethylene glycols, whereas AEs with longer alkyl substituents, such as the 2Bu-C(8)AE, biodegrade through hydrolytic oxidation of the alkyl and polyethoxylic chains, which leads to formation of AE metabolites with carboxylic groups on both the hydrophobic and hydrophilic moieties.

There is a general paucity of literature data dealing with surfactants monitoring in sediments using specific methodologies. The only surfactants for which a consistent data set already exists are Linear Alkylbenzene Sulphonate (LAS) and Nonyl Phenol Ethoxylate (NPE). Concentrations of LAS and NPE, have in fact been monitored in both fresh wafer and marine sediments and were generally found to range from 0 to 5.0 mg/kg. Higher levels were reported only for some sediments collected close to untreated or inadequately treated sewage effluent discharges. This paper reviews the existing monitoring data for these surfactants in sediments and also reports the preliminary results of a recent monitoring programme carried out on the bottom sediments of the main watercourse in Italy, the river Po, using HPLC methodologies. For the first rime, attention has been focused not only on LAS but also on Alcohol Ethoxylate (AE). To our knowledge this is the first example of a concentration-specific estimate of AE in sediments. These results will be discussed and compared with the limited toxicity information which is available on benthic organisms.

Two model compounds, representing the main classes of iso‐branching present in commercial LAS, have been synthesized, namely the sodium salt of the 2‐phenyl, 5‐methyl undecane sulphonic acid (iso‐LAS I) and 6‐phenyl, 6‐methyl undecane sulphonic acid (iso‐LAS II). The biodegradability of iso‐LAS I and iso‐LAS II was determined in the OECD 301 E screening test and the OECD 303 A continuous activated sludge (CAS) test. Linear C12 LAS was included in these test as a control. Primary and ultimate biodegradation were measured by applying specific HPLC analyses to the determination of the residual intact material and biodegradation intermediates, the sulphophenyl carboxylates (SPC). Complete primary biodegradation of iso‐LAS I and iso‐LAS II was observed; in the CAS test their ultimate biodegradation reached 75 to 90% as compared to a value of 99% observed for C12 LAS. The predominate SPC intermediates, SPC I and SPC II, were derived from the biodegradation of iso‐LAS I and iso‐LAS II, respectively. Their structures were determined by NMR. SPC I is a diastereoisomer mixture at the same 50: 50 ratio as that of iso‐LAS I. These results demonstrate that the iso‐branching components of commercial LAS should be efficiently removed and extensively mineralized, as LAS itself, in biological sewage treatment plants.

Two important commercial surfactants, linear alkylbenzene sulphonate (LAS) and alcohol ethoxylate (AE), were tested for their biodegradation in confirmatory continuous activated sludge (GAS) systems, according to the simulation OECD 303 A method. Two commercial LAS products, produced from two C-10-C-13 alkyl chain LABs of our production, the first using HF and the other AlCl3 as catalyst, and one commercial AE derivative, obtained from C-12-C-15 alkyl chain oxo-alcohol of our production and with an average ethoxylation degree of 7 were examined. The innovative aspect of such a biodegradation study consists in the application of specific analytical methodologies, using high performance liquid chromatography (HPLC) as final detection technique, to determine the residual amount of the surfactants (in case of LAS also of the biodegradation intermediates) in effluents and sludges of the CAS tests in addition to DOC (Dissolved Organic Carbon) measurements. This allows to get a specific assessment of the degree of the primary and ultimate biodegradation of LAS which can be attained when it is disposed in sewage treatment plants. The results obtained by HPLC for the primary biodegradation are > 99% for the three studied species. The ultimate biodegradation rates determined by HPLC are with 95% (LAS-HF) and 98% (LAS-AlCl3) more than 10% higher than those obtained via DOC determination (84.9 and 85.1%, resp.).

A commercial Linear Alkylbenzene Sulphonate (LAS) of HF-type, with a low content (< 0.5%) of Di Alkyl Tetralin Sulphonates (DA TS) and an iso-branching amount of 6.5 %, was tested in a prolonged batch-biodegradation experiment called living test, where the product, as the only carbon source, was continuously fed by gradual additions for 80 days to a screening biodegradation system. The final organic residue of this prolonged biodegradation test was characterized in detail showing that no accumulation of iso-branching structures had occured. The organic residue is mostly made up of 4 Sulpho Phenyl Carboxylates (SPC) originating from the linear components of LAS.