Abstract  Alcohol ethoxylates (AEs) are an important group of nonionic surfactants. Commercial AEs consist of a mixture of several homologues of varying carbon chain length (Cx) and degree of ethoxylation (EOy). The major disposal route of AE is down the drain to municipal wastewater treatment plants that discharge into receiving surface waters. Sorption of AE homologues onto activated sludge and river water solids is an important factor in assessing exposure of AE in the environment. This study presents the experimental determination of sorption coefficients for a wide array of AE homologues including five alcohols under environmentally relevant conditions and combines these data with literature data to generate a predictive model for the sorption of AEs in the environment. These results demonstrate that sorption can be effectively modeled using a log Kd vs. Cx and EOy predictive equation having the form log Kd = 0.331C - 0.00897EO - 1.126(R2 = 0.64).

Abstract  Repeat applications of an artificial monolayer to the interfacial boundary layer of large agricultural water storages during periods of high evaporative demand remains the most commercially feasible water conservation strategy. However, the interfacial boundary layer (or microlayer) is ecologically distinct from subsurface water, and repeat monolayer applications may adversely affect microlayer processes. In this study, the natural cleansing mechanisms operating within the microlayer were investigated to compare the biodegradability of two fatty alcohol (C16OH and C18OH) and one glycol ether (C18E1) monolayer compound. The C16OH and C18OH compounds were more susceptible to microbial degradation, but the C18E1 compound was most susceptible to indirect photodegradation. On clean water the surface pressure and evaporation reduction achieved with a compressed C18E1 monolayer was superior to the C18OH monolayer, but on brown water the surface pressure dropped rapidly. These results suggest artificial monolayers are readily degraded by the synergy between photo and microbial degradation. The residence time of C18OH and C18E1 monolayers on clear water is sufficient for cost-effective water conservation. However, the susceptibility of C18E1 to photodegradation indicates the application of this monolayer to brown water may not be cost-effective.

Abstract  SIDS INITIAL ASSESSMENT: There is need for further work. SHORT SUMMARY OF THE REASONS WHICH SUPPORT THE RECOMMENDATION: The substance is firmly bound to sediments, and therefore anaerobic biodegradation can be an important factor. A 21-day test in daphnids indicated that the substance may be toxic at a range of between 1 and 3mg/l. FURTHER WORK RECOMMENDED: Determination of anaerobic biodegradability. Depending on the results of this test, it may be considered whether or not long-term fish toxicity testing is required.

Abstract  The examination of a number of potential and currently used carrier fluids for invert emulsion drilling fluids in the ECETOC screening test revealed clear differences with respect to their easy anaerobic biodegradability. Fatty acid- and alcohol-based ester oils exhibited excellent anaerobic degradation to the gaseous final end products of the methanogenic degradation pathway, methane and carbon dioxide. Mineral oils, dialkyl ethers, alpha-olefins, polyalphaolefins, linear alkylbenzenes and an acetal-derivative were not or only slowly degraded. Although the poor degradation results obtained in the stringent ECETOC screening test may not be regarded as final proof of anaerobic recalcitrance, nevertheless, these results were found to be in line with the present understanding of the structural requirements for anaerobic biodegradability of chemicals. The validity of the conclusions drawn is corroborated by published results on the anaerobic biodegradation behaviour of ester oils, mineral oils and alkylbenzenes in marine sediments.

Abstract  A standardized, feasible test system for assessing the environmental behavior of chemicals in ecotoxicological terms and for setting up priority lists was described earlier. 14C chemicals were used in environmentally relevant concentrations. The bioaccumulation potential of chemicals was determined from tests with algae and fish; mammalian retention and elimination were investigated in a test with rats. Information about biodegradability, metabolism, accumulation, and bound residues was provided by the activated sludge test, while the possibility of photomineralization of the organic compounds was studied by irradiation with uv light of wavelength above 290 nm. The presentation of the data is by ranking in tables: they are either ranked in order of decreasing accumulation in the algae, fish, rat, and activated sludge tests (lipophilic substances such as hexachlorobenzene, chlorinated biphenyls, aldrin, etc., displaying the highest accumulation, are on top of the lists); or they are ranked in order of increasing degradability in the activated sludge and photomineralization tests (the most persistent chemicals thus again are on the top of the list). The data obtained from the accumulation tests are correlated with respective physicochemical properties of the chemicals and the results of the tests are compared with one another for ecotoxicological profile assessment.

Abstract  A test system is described for assessing the mineralization of 14C-radiolabeled compounds to carbon dioxide (CO2) and methane (CH4) under anaerobic conditions. Environmentally realistic concentrations of test chemicals were incubated with anaerobic digester sludge in sealed vessels at 35 °C. The headspace of these vessels was continuously purged with nitrogen, which was passed through a series of potassium hydroxide (KOH) scrubbers to trap 14CO2. This effluent gas was mixed with oxygen and passed through a combustion tube containing cupric oxide at 800 °C to convert 14CH4 to 14CO2, which was subsequently trapped in a second series of KOH traps. Trapping efficiency was 97.1 ± 5% for 14CO2 and 108 ± 13% for 14CH4. The system was used to evaluate the mineralization of several organic chemicals including glucose, palmitic acid, hexadecanol, and two surfactants, alkyl ethoxylate sulfate (AES) and alkyl sulfate (AS), in anaerobic digester sludge. Total yields of 14CH4 and 14CO2 from these compounds exceeded 80%, and the total mass balances generally exceeded 95%. Mineralization of hexadecanol was described by a simple first-order production equation, while that of the other compounds was best described by a three-half-order model. This system provided excellent recovery of radioactive gases and consequently excellent mass balances. Given the reproduction of in situ condition and the realistic ratio of test material to biomass, the test system also generated relevant kinetic data. It, therefore, has application for demonstrating the significance of biodegradation as a removal mechanism during anaerobic digestion as well as determining the completeness of anaerobic biodegradation.

Abstract  SIDS dossiers already existed for 1-Dodecanol (CAS 112-53-8) and 1-Octadecanol (CAS 112-92-5) (published in 1998 and 1995 respectively); the present document updates and extends the earlier ones; brings in new information, and therefore replaces it. No conclusions drawn in the earlier review are amended. Available data for these substances are compiled in SIDS dossiers related to each CAS number. The reliability of each data point has been considered during this period of review, in accordance with the guidance of the Fraunhofer Institut für Toxikologie und Aerosolforschung. The following standard reliability codes, defined by Klimisch et al. (1997)1, apply, in accordance with the SIDS guidance: (1) Valid without restriction (2) Valid with restrictions (3) Invalid (4) Not assignable. Results considered to be Invalid are not used in the discussions or conclusions in this report. However, results which are of Non-assignable reliability may be fully valid, although insufficient details were available to be sure of this; therefore reliability (4) results are used in this report. The reliability code of each data point is given. Key studies are flagged in the SIDS dossiers. These are studies with the highest reliability/adequacy. If several studies showed comparable reliability/ adequacy, the study with the lowest LC/LD/EC50 or NOEC/ NOAEL has been indicated as the key study. For some endpoints, fully reliable results are not available and it has been necessary to use a weight of evidence including results of studies of non-assignable reliability. In such cases the results are identified as key studies as they are of high importance to the data set. For transparency, some study summaries in the SIDS dossier have been transferred from the previously published version of IUCLID or from the previous SIDS submission. In some cases, it has not been possible to retrieve the original literature/study reports using the reported citation or as a result of literature searching. In some cases, change of business ownership meant that internal study reports cited in previous summaries could not be accessed. In some other cases, e.g. certain non-SIDS endpoints, and in areas where a very large amount of literature has been published, it was not considered necessary to pursue all individual published sources due to weight of evidence of more reliable results. In all cases, reliability (4) applies, because the original documentation has not been reviewed in the development of the dossier. Such results are clearly identified in the SIDS dossier and more details are given therein.

Abstract  The recently developed technique of aerosol chemical ionization mass spectrometry is used to study the reaction of ozone with particles consisting of unsaturated organic molecules, including oleic acid, linoleic acid, oleyl alcohol, and 1-octadecene. The reactive uptake coefficients, gamma, for polydisperse aerosols with mean diameters of 800 nm are determined from the rates of loss of the particle species to be (7.5 +/- 1.2) x 10(-4) for oleic acid, (1.1 +/- 0.2) x 10(-3) for linoleic acid, (7.5 +/- 1.3) x 10(-4) for oleyl alcohol, and (2.4 +/- 0.4) x 10(-4) for 1-octadecene. The ozonolysis products of oleic acid particles are studied in detail with simultaneous detection of the four primary products: nonanal, nonanoic acid, 9-oxononanoic acid, and azelaic acid. All four products are found to exist in the reacted particles, though nonanal is also detected in the gas phase indicating that it partially evaporates. The yield of azelaic acid is determined to be 0.12 +/- 0.04, and the yields of nonanal and 9-oxononanoic acid are found to be larger than the yields of the other products suggesting the existence of secondary reactions involving the Criegee intermediates. A fifth product, 9-oxooctadecanoic acid, is detected with a small yield (similar to0.02) and is believed to result from different secondary reactions. Implications of these results for the alteration of chemical and physical properties of aerosols as they are aged in the atmosphere are discussed.

Abstract  The anaerobic degradation of fatty alcohol polyglycol ethers was studied in a model sludge digester employing stearyl alcohol ethoxylate which was super(14)C-labelled either in the alkyl or in the heptaglycol chain. After 4-weeks' incubation of the super(14)C-compounds at 35 degree C in the presence of raw sludge as additional digestible substrate more than 80% of the initial radioactivity was found as methane and carbon dioxide. In addition, the major part of radioactivity in the digested sludge, corresponding to nearly 10% of added super(14)C, was attributable to biomass so that ultimate degradation of the two model surfactants amounted to more than 90%. Analysis of the small fraction of radiolabelled metabolites in the sludge supernatant allowed conclusions with regard to the anaerobic degradation route of linear alcohol ethoxylates. After primary biodegradation of the surfactant molecule by scission into the alkyl and poly(ethylene glycol) moieties the further biodegradation of the latter seems to proceed as under aerobic conditions, i.e. via oxidative or hydrolytic depolymerization steps. Eventually, ultimate biodegradation of the obtained monomers (C sub(2)-units) leads to the formation of the gaseous end products.(DBO)