ISSN:0730-7268    

DOI:10.1002/etc.5620121001

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractAn aquatic hazard assessment was conducted for branched and linear nonionic surfactants using toxicity and biodegradation measurements. Four nonionic alcohol ethoxylate surfactants with different degrees of branching (ranging from 0.1, essentially linear, to 4.0 internal methyl groups per hydrophobe) were evaluated for neat surfactant toxicity, degradation in laboratory sewage treatment units, and aquatic toxicity of treated effluents. Acute testing with neat surfactants showed ranges for EC50s of 1.3 to 11.6 mg/L forDaphnia, 1.6 to 6.1 mg/L forPimephales promelas(fathead minnow), and 1.5 to 11.4 mg/L for Microtox®. Chronic testing of algae showed NOECs of 1 to 10 mg/L and maximum acceptable toxicant concentrations (MATCs) of 0.8 to 14.2 mg/L. Seven‐day chronic estimation tests showed MATCs of 0.6 to 41.4 mg/L forPimephales promelasand 1 to 14 mg/L forDaphnia. Effluents collected from treatment units receiving a 50‐mg/L surfactant feed at 25°C showed no acute toxicity to eitherDaphniaor fathead minnows, with the exception of a unit containing nonylphenol ethoxylate. Chronic effluent toxicity was greatest in effluent from the nonyl‐phenol ethoxylate unit and least in the effluent from the linear alcohol ethoxylate unit. Chronic toxicity of the highly branched C13alcohol ethoxylate effluent was greater than that for the linear alcohol ethoxylate unit e

ISSN:0730-7268    

DOI:10.1002/etc.5620121002

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractLaboratory and field studies were conducted with linear alkylbenzene sulfonate (LAS) to evaluate the use of laboratory‐generated NOECs for protecting aquatic organisms in outdoor experimental streams. Fathead minnows (Pimephales promelas) and freshwater amphipods (Hyalella azteca) were exposed in the laboratory to an environmentally realistic mixture of LAS (average chain length C11 9) for 7 d; fathead minnows were also exposed in a 28‐d study. Calculated NOEC values based on survival and growth ranged from 0.3 to 0.9 mg/L for fathead minnows and from 0.6 to 1.4 mg/L for amphipods. Toxicity of LAS in 4‐, 7‐, and 28‐d exposures of fathead minnows was similar because mortality occurred within the initial 24 h of exposure; mortality was more sensitive than growth as a chronic end point. The addition of 5% sewage effluent to well and stream water had little effect on the bioavailability of LAS; however, total organic carbon levels were low (<3 mg/L) in all treatments. A 45‐d exposure of three outdoor experimental streams to 0.36 mg/L LAS had no effects on survival of fathead minnows or amphipods, dynamics of benthic invertebrates, growth of periphyton, or processing of detrital leaves. Results indicated that the laboratory‐generated NOEC for LAS was protective of experimental stream communities under the studi

ISSN:0730-7268    

DOI:10.1002/etc.5620121003

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractLinear alkylbenzene sulfonate (LAS) biodegrades easily and loses its tensioactive properties quickly through a primary biodegradation process, as many works of literature testify. Many studies have been carried out in laboratories or in pilot plants, whereas few have been undertaken in a wastewater treatment plant (WWTP). In Italy, unlike in other countries, no detailed investigation has been made so far to establish LAS biodegradation in real WWTP conditions. EniChem Augusta (EA) and Consorzio Po‐Sangone (CPS) have worked together for over two years on this problem, taking into consideration the large (flow rate: approximately 400 × 103m3/d) and central active sludge WWTP of the metropolitan area of Torino, north of Italy. Specific LAS data have been obtained, using established HPLC techniques, in influent and effluent streams, in the dissolved (waters) and adsorbed (suspended solids and sludges) phases, to reach a complete mass balance. LAS removal>99% and LAS biodegradation of approximately 85% have been observed. Attention also has been given to LAS intermediates of biodegradation, namely the sulfophenyl carboxylates (SPC), using HPLC and GC‐MS techniques, the latter after derivatization. The SPCs have been found present only in the waters and not in the adsorbed phases (SS and slud

ISSN:0730-7268    

DOI:10.1002/etc.5620121004

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractEffects of the cationic surfactant lauryl trimethyl ammonium chloride (C12‐TMAC) on growth, reproduction, cellulolytic enzyme activity, and larval colonization of Asiatic clams (Cor‐bicula fluminea)were investigated in experimental stream mesocosms. Clams from three different populations and of two known morphotypes were evaluated for growth in two 8‐week experiments in fall 1989 and spring 1990. Growth was impaired at 185 μg TMAC per liter or greater for both seasons and was not morphotype dependent. Mortality, cellulolytic enzyme activity, and adult reproductive condition were not altered up to concentrations of 1153 μg/L. However, larval clam (ped‐iveliger) colonization was affected at concentrations of 43 μg/L. It is not known at this time to what extent the effects on pediveligers would be manifested relative to recruitment to later life stages. These findings were compared to a published safety assessment for mono‐alkyl quanternaries, of which TMAC is a member. The findings reported here do not substantially alter conclusions from previous studies; however, clams appear to be among the more sensitive taxa stud

ISSN:0730-7268    

DOI:10.1002/etc.5620121005

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractIn situ toxicity tests were conducted to determine the toxicity of linear alkyl‐ (dodecyl‐) benzenesulfonate (LAS) on a natural periphyton community. Colonized periphyton were exposed to C11 9‐LAS in 21‐d continuous‐flow toxicity studies conducted in the Little Miami River (Ohio) above and below a wastewater treatment plant outfall. The lowest measured first‐effect levels were 3.3 and 16.6 mg/L, respectively, in the two locations, based on reductions in structural and functional community characteristics. The presence of 20 to 30% effluent did not increase the toxicity of LAS. The field‐derived effect levels confirmed the low phytotoxicity observed in most previously conducted laboratory toxicity studies with cultured algae. In addition, the field‐derived effect levels exceeded measured environmental concentrations, which supports the environmental safety of LA

ISSN:0730-7268    

DOI:10.1002/etc.5620121006

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractAlthough a growing number of investigations have dealt with selected aspects of the behavior of surfactants in soil and their effects on various soil properties, systematic approaches like those applied to pesticides or heavy metals are still rare. Considering that soil is exposed to a considerable quantity of surfactants, it would appear necessary to do more intensified research in this field. Based on a comprehensive review of the literature, the author briefly outlines the behavior and fate of surfactants in soil and presents a synopsis from the viewpoint of a pedologist. Even at low concentrations, surfactants seem to alter soil physics, soil chemistry, and soil biology significantly, whereby sorption processes play a dominant role. The report tries to integrate the most important research results in this field and to interpret them against the background of the complex structure of the soil system.

ISSN:0730-7268    

DOI:10.1002/etc.5620121007

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractA range of Organisation for Economic Cooperation and Development (OECD) guideline test systems was used to determine the extent and possible mechanisms of biodegradation of dialkyl sulphosuccinate (DASS, C6/C8). Primary biodegradation of DASS was virtually complete in OECD guideline tests and in simulations of activated sludge sewage treatment systems under both optimal and adverse conditions, and of an anaerobic digester. Ultimate biodegradation increased from about 50% in ready tests to 94% in more powerful inherent tests. [14C]DASS was used to determine the fate of the surfactant in activated sludge and in surface waters. Mechanistic studies were performed to ascertain the biodegradative pathway of [14C]DASS. A putative degradation pathway for DASS is proposed.

ISSN:0730-7268    

DOI:10.1002/etc.5620121008

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractReductive dechlorination of PCBs by Hudson River sediment microorganisms was investigated using individual congeners, 2,3,4,2′,4′,5′‐, 2,4,5,2′,4′,5′‐, 2,3,4,5,6‐, 2,4,2′,4′‐, and 3,4,3′,4′‐chlorobiphenyls (CBPs) in long‐term studies lasting 15 to 20 months. The dechlorination of 2,3, 4,2′,4′,5′‐CBP yielded 2,4,5,2′,4′‐, 2,4,2′,4′‐, 2,4,2′,5′‐, and 2,4,2′‐CBPs; notably absent was 2,2′‐CBP. Yet, the total molar concentration of all congeners decreased with time and at 15 months accounted for only 25% of the initial concentration of the parent compound. 2,3,4,5,6‐CBP produced 2,3,5,6‐, 2,4,6‐, and 2,6‐CBPs. At 15 months the sum of all congeners accounted for only about 50% of the initial amount of the parent congener. On the other hand, 2,4,5,2′,4′,5′‐CBP yielded six daughter products, including 2,2′‐CBP, and did not show any decrease in total molar concentration even at 20 months. 2,4,2′,4′‐CBP did not show any change at 15 months. These results indicate that anaerobic PCB biotransformation may include mechanisms other than dechlorination and that the mechanisms are congener dependent. Biphenyl was detected with 3,4,3′,4′‐CBP, indicating complete dechlorination; however, it accounted for<10% of the total molar loss.14C‐labeled tracer of this congener showed that all

ISSN:0730-7268    

DOI:10.1002/etc.5620121009

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe functional dependencies of equilibrium and nonequilibrium sorption parameters on solute molecular descriptors were analyzed for 29 organic compounds and two soils. Similar correlation patterns were obtained with all three evaluated size/shape descriptors (molecular surface area, van der Waals volume, molecular connectivity). The functional dependencies of equilibrium distribution coefficients on the solute molecular descriptors were analyzed for three systems used as phe‐nomenological models of sorption by soil (octanol, reversed‐phase HPLC packing material [RPLC], polymer). The correlation patterns exhibited by the three models were compared to those reported for the soil systems. The correlation patterns exhibited by the soil data were similar to the patterns exhibited by the polymer systems and dissimilar to those exhibited by the octanol and RPLC systems. In addition, the correlation pattern between the sorption rate coefficient and molecular connectivity was similar to that between polymer‐diffusion coefficients and molecular connectivity. Hence, it appears that the polymer analog may be the most appropriate of the three models for representing both equilibrium and nonequilibrium sorption by soil. Based on these results, the polymer analog is suggested as the phenomenological model of choice for investigating and evaluating the sorption dynamics of low‐polarity organic compounds in soil

ISSN:0730-7268    

DOI:10.1002/etc.5620121010

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY