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The sorption of four endocrine disruptors, bisphenol A (BPA), estrone (E1), 17β-estradiol (E2), and 17α-ethinylestradiol (EE2) in tropical sediment samples was studied in batch mode under different conditions of pH, time, and sediment amount. Data obtained from sorption experiments using the endocrine disruptors (EDs) and sediments containing different amounts of organic matter showed that there was a greater interaction between the EDs and organic matter (OM) present in the sediment, particularly at lower pH values. The pseudosecond order kinetics model successfully explained the interaction between the EDs and the sediment samples. The theoretical and experimentally obtained q e values were similar, and k values were smaller for higher SOM contents. The k F values, obtained from the Freundlich isotherms, varied in the ranges 4.2-7.4×10 −2 (higher OM sediment sample, S 2 ) and 1.7×10 −3 -3.1×10 −2 (lower OM sediment sample, S 1 ), the latter case indicating an interaction with the sediment that increased in the order: EE2>>E2>E1>BPA. These results demonstrate that the availability of endocrine disruptors may be directly related to the presence of organic material in sediment samples. Studies of this kind provide an important means of understanding the mobility, transport, and/or reactivity of this type of emergent contaminant in aquatic systems.

Interações entre substâncias húmicas aquáticas (SHA), de rios tropicais, e dois interferentes endócrinos (IE) foram estudados utilizando sistema de ultrafiltração em fluxo tangencial equipado com membrana de celulose de 1 kDa com a finalidade de separar os IE livres da fração ligada as SHA. A quantificação de 17a-etinilestradiol e bisfenol A foi realizada utilizando cromatógrafo a gás acoplado a espectrômetro de massas (GC-MS). O tempo de equilíbrio entre as SHA e IE foi de aproximadamente 30 min, e as capacidades complexantes do 17a-etinilestradiol e bisfenol A foram em torno de 18,53 e 2,07 mg g -1 de carbono orgânico total (COT), respectivamente. A maior interação das SHA ocorreu para 17a-etinilestradiol, em relação ao bisfenol A, devido a presença de hidrogênio na estrutura do 17a-etinilestradiol, que podem interagir com os grupos oxigenados presentes nas SHA. Os resultados indicam que as SHA podem influenciar fortemente no transporte e reatividade dos interferentes endócrinos presentes em sistemas aquáticos.Interactions between two endocrine disruptors (ED) and aquatic humic substances (AHS) from tropical rivers were studied using an ultrafiltration system equipped with a 1 kDa cut-off cellulose membrane to separate free ED from the fraction bound in the AHS. Quantification of 17a-ethynylestradiol and bisphenol A was performed using gas chromatography-mass spectrometry (GC-MS). The times required for establishment of equilibrium between the AHS and the ED were ca. 30 min, and complexation capacities for 17a-ethynylestradiol and bisphenol A were 18.53 and 2.07 mg g -1 TOC, respectively. The greater interaction of AHS with 17a-ethynylestradiol, compared to bisphenol A, was due to the presence of hydrogen in the structure of 17a-ethynylestradiol, which could interact with ionized oxygenated groups of the AHS. The results indicate that AHS can strongly influence the transport and reactivity of endocrine disruptors in aquatic systems.Keywords: water, pollution, endocrine disruptors, aquatic humic substances, complexation capacity IntroductionPopulation increase, the development of new products, and intensified use of terrestrial and aquatic resources in industry and agriculture have resulted in the introduction into the environment of new compounds that may cause toxicity in humans and animals. Endocrine disruptors (ED) are often found in surface waters and effluents, where they can pose health risks even at low concentrations. In 1996, the European Commission defined this class of compounds as "exogenous substances that cause adverse health effects in the intact organism, or in its descendents, resulting in alterations of endocrine functions". 1,2 ED can block cellular receptor sites or increase the production and/or secretion of hormones, hence interfering in the reproductive systems of living organisms. 3-5 Many Characterization of the Interactions between Endocrine Disruptors and Aquatic Humic Substances J. Braz. Chem. Soc. 1104 compounds are suspected of interfering with the endocrine system, 6 inclu...

Endocrine disruptors (EDs) are widespread in the environment, especially aquatic systems, and cause dangerous effects on wildlife and humans. This work was aimed to assess the capacity of radish (Raphanus sativus L.) and ryegrass (Lolium perenne L.) seedlings to tolerate and remove two combinations of EDs containing bisphenol A (BPA), 17alpha-ethynilestradiol (EE2), and linuron from four aqueous media: distilled water, a solution of natural organic matter (NOM), a lake water and a river water. Seeds of the two species were germinated in each contaminated medium and, at the end of germination, the seedling growth was evaluated by biometric measurements and residual EDs were quantified by chromatographic analysis. Biometric measurements revealed that the phytotoxicity of the two combinations of EDs depended on the medium used. Radish showed a discrete tolerance in distilled water and lake water but was inhibited in the solution of NOM and river water. Ryegrass was negatively affected mainly in river water. The concentration of each ED appeared significantly reduced in all media in the presence of seedlings of both species, but not in the blanks without plants. In 5 days, radish removed up to 88% of BPA, 100% of EE2 and 42% of linuron, and in 6 days ryegrass removed up to 92% of BPA, 74% of EE2 and 16% of linuron. The considerable removal capacity of radish and ryegrass in all media tested encourages the use of phytoremediation to remove EDs from waters.

Abstract:We use a set of three resistive sensors based on undoped multi-walled carbon nanotubes, B-doped multi-walled carbon nanotubes, and N-doped multi-walled carbon nanotubes to study fungal infection in strawberries inoculated with Rhizopus sp. or with Aspergillus sp. section Nigri. We apply tristimulus analysis using the conductance variation of the sensors when exposed to the infected strawberries to distinguish between uninfected strawberries and strawberries infected with Rhizopus sp. or with Aspergillus sp. section Nigri, and to obtain a graphical representation providing a tool for the simple and fast detection and identification of the fungal infection.

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