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Bacterial communities were examined in replicate lab-scale activated sludge reactors after a period of several months of enrichment with non-ionic nonylphenol ethoxylate (NPE) surfactants. Four sequential batch reactors were fed with synthetic sewage, two of which received additionally NPE. Small subunit rDNA-derived denaturing gel gradient electrophoresis (DGGE) profiles and 16S rDNA clone libraries were dominated by clones of Gammaproteobacteria class. Sequences of the other codominant rDNA phylotypes observed only in DGGE from NPE-amended reactors were, respectively, associated with the Group III of the Acidobacteria phylum. Intriguingly, 16S rRNA content from abundant Gammaproteobacteria cells was unexpectedly low. In addition to Acidobacteria, rRNA-derived DGGE profiles were dominated by members of the order Burkholderiales (of the Betaproteobacteria) and of the genus Sphingomonas (a member of the Alphaproteobacteria). Specific oligonucleotide probes for the selected ribotypes were designed and applied for quantitative real time polymerase chain reaction and fluorescence in situ hybridization, confirming their dominance in treated reactors. The parallel abundance of unique phylotypes in replicate reactors implies a distinctive selection of dominant organisms, which are better adapted to specialized niches in the highly selective environment.

In the present work we have developed an analytical methodology for the determination of nonylphenol (NP) and nonylphenol mono- and di-ethoxylates (NP1EO and NP2EO) in water samples. The applicability of this methodology was proved by means of the analysis of environmentally relevant aqueous samples from Buenos Aires. This constitutes a starting point for a rigorous assessment of the incidence of NPnEO surfactants in Argentina, as only very few, qualitative or semi-quantitative data on the occurrence of these compounds in local systems were available up to this time. Enrichment of the analytes was carried out by solid-phase extraction on a C-18 sorbent, followed by elution with ethyl acetate. Normal-phase high performance liquid chromatography on an amino-silica column and fluorescence detection at excitation-emission wavelengths of 230-300 nm were employed for separation and quantification of the analytes. Confirmation of peak assignment in selected real samples was performed by off-line coupling HPLC with GC-MS analysis. A non-polar GC capillary column was used, and a characteristic peak pattern was obtained for the alkyl chain isomers of each ethoxylated homologue and NP. GC-MS analyses yielded in all cases purity levels higher than 80% for the HPLC collected fractions. The elevated concentrations found for the estrogenic metabolites of NPnEO are in accordance with an unrestricted use of this class of non-ionic surfactants in the country.

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In Latin America, use of alkylphenol ethoxylates is unrestricted and widespread. However, their environmental incidence is still little studied. In order to investigate the occurrence, distribution and main sources of the endocrine disruptors nonylphenol (NP), nonylphenol mono‐ and di‐ethoxylate (NP1EO, NP2EO), we analyzed water and sediments from thirteen sites in high and low population densities regions of Argentina. Also ten biosolid samples from a municipal sewage treatment plant were analyzed. Ranges for NP were 21–6359 µg kg−1 in sediments, 0.1–6.2 µg L−1 in water and 64–112 mg kg−1 in sludge; for NP1EO were 7–3357 µg kg−1 in sediments, 0.1–9.2 µg L−1 in water and 8–140 mg kg−1 in sludge and for NP2EO were 1–437 µg kg−1 in sediments, 0.1–5.2 µg L−1 in water and 2–23 mg kg−1 in sludge. The highest levels were associated with proximity to industry and sewage effluents discharge. In biosolids we found predominantly NP, followed by NP1EO and NP2EO, consistently with the metabolic potential of engineered systems. Our findings are in agreement with historical reports for Europe and North America, indicating an important incidence of the xenoestrogens also in this important geographical region. Contrasted to guide values, they show a potential threat to the water and terrestrial environments.

Chemical changes in leaf input to forest soils have been reported to affect decay processes. In this work, litter mass loss and decomposition constants (k) during 200 days in solid-state fermentation of the native tree Celtis tala Gill. ex Planch. and the exotic one Ligustrum lucidum Ait. with three common litter saprotrophic basidiomycetes were compared. Alterations in litter quality were characterized by solid-state 13C NMR spectroscopy, pH, soluble sugars, ammonium, proteins, and phenol content determination and were associated with extracellular lignocellulolytic enzyme production. Differences in substrate decomposition related to litter type were observed for Leratiomyces ceres, achieving a higher k in the exotic L. lucidum litter, which might be attributed to the induction of manganese peroxidase activity. Substrate preference for alkyl C and more degradation of lignified compounds were found in such substrates. Although no statistical differences in mass loss were observed for the rest of the fungi assayed, we detected changes in several of the parameters evaluated. This suggests that exotic invasions may alter ecosystem functioning by accelerating decomposition processes through an increased fungal ligninolytic activity.

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