PHYTOREMEDIATION OF THREE ENDOCRINE DISRUPTORS IN NATURAL AND NOM-ENRICHED WATERS Bruno Barboza Cunha1,2*, C. Eliana Gattullo3, André Henrique Rosa2, Elisabetta Loffredo3 1
Department of Analytical Chemistry, Institute of Chemistry, São Paulo State University (UNESP), AraraquaraSP, Brazil; 2Department of Environmental Engineering, São Paulo State University (UNESP), Sorocaba-SP, Brazil; 3Dipartimento di Biologia e Chimica Agro-forestale ed Ambientale, University of Bari, Bari, Italy.
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[email protected] Keywords: phytoremediation, endocrine disruptors, radish.
Abstract Phytoremediation is a promising technology for the decontamination of water from endocrine disruptors (EDs), even if information about its application in natural waters are still scarce. In this study, the phytoremediation of the EDs bisphenol A, linuron and 17α-ethynilestradiol was investigated during the germination of radish in four different media: bidistilled water, dissolved natural organic matter and two freshwaters collected in Southern Italy. In water, seedlings were not intoxicated by the ED mix and removed a great amount of each product. In the other three media, seedlings were slightly inhibited by the ED mix but maintained the same efficiency of phytoremediation showed in water samples. Results of this study encourage the use of phytoremediation for the detoxification of aquatic systems. Introduction Endocrine disruptors are exogenous substances that act like hormones in the endocrine system of animals and disrupt the physiologic function of endogenous hormones. They are sometimes also referred to as hormonally active agents, endocrine disrupting chemicals, or endocrine disrupting compounds1,2,3. Among EDs, the xenoestrogens bisphenol A (BPA) and 17α-ethynilestradiol (EE2) are used, respectively, in the production of epoxy resins and polycarbonates, and as contraceptive oral pills, whereas linuron (LIN) is one of the most common phenylurea herbicides. These three EDs are conveyed to aquatic systems by various natural or anthropogenic mechanisms reaching concentrations ranging from some µg L-1 to mg L-1 4,5. In order to remove these contaminants from the environment, efficient and sustainable technologies are required. Phytoremediation is one of the most promising techniques which uses plants to uptake, transform or stabilize pollutants present in sediments, soils and waters. Recent studies demonstrated the feasibility to apply this technology for the decontamination of simple aqueous systems polluted by EDs6,7. Few information are reported in the literature about the use of phytoremediation in real and more complex aquatic systems, where microorganisms, organic matter content and other contaminants could affect the removal efficiency of plants. On these bases, the aim of this work was to investigate the ability of radish (RA, Raphanus sativus) to remove BPA, LIN and EE2 from different real aquatic
systems. Materials and Methods Phytoremediation was tested in the following media: bidistilled water (control), aqueous solution of 20 mg L-1 of Suwanne River NOM obtained by the International Humic Substances Society (IHSS) and two freshwaters collected in Puglia (Italy), one from Sassano Lake (SL) and the other from Morelli River (MR). Twenty seeds of RA were placed on a cotton gauze covering glass pots containing 50 mL of the above mentioned liquid matrices, or the same added with a mix of BPA, LIN and EE2 at the concentrations of 1.0 mg L-1 of BPA and LIN, and 0.1 mg L-1 of EE2. All media were added with 1.5% methanol in order to increase EE2 and LIN solubility. A blank without seeds was performed for each medium in order to assess the degradation of EDs in absence of plants. The germination was performed in a Phytotron growth chamber at 21±1°C in the dark for 6 days. At the end of germination, seedling fresh weight was measured in order to establish ED phytotoxicity. The final amount of BPA, LIN and EE2 in the medium was determined by high performance liquid chromatography (HPLC) using a diode array detector (DAD) at 210 nm wavelength. Previously, samples were extracted and concentrated by solid phase extraction (SPE) by using C18 cartridges. All treatments were replicated 4 times. Data were referred to water treatment and statistically analyzed by one-way analysis of variance (ANOVA) and the least significant difference test (LSD). Results and Discussion In the absence of EDs, seedlings fresh weight decreased significantly with respect to the control only in MR, probably because of its high salinity. In the presence of ED mix, the fresh weight decreased in all media with the exception of water treatment. The percentage of ED removal, calculated by the difference between residual ED in the blanks and that measured at the end of germination in any media, is reported in Figure 1.
Figure 1 Removal of BPA, LIN and EE2 by Radish in four different media.
No significant reduction of each ED was observed in each blank, whereas a considerable decrease was measured in all media in the presence of plants. Radish removed from water 80% of BPA, 35% of LIN and reduced EE2 to undetectable level. A similar high removal efficiency was observed also in the other media despite the general reduction of plant biomass, with the only exception of MR where the BPA removal was slightly lower (53%, P ≤ 0.05). Radish removal efficiency was calculated also in terms of mass (µg) of ED removed per gram of fresh biomass. In water, RA removed 37 µg g-1 BPA, 18 µg g-1 LIN and 5 µg g-1 EE2. In NOM and SL, RA efficiency was not significantly different with respect to water, but in MR it was strongly higher, exactly 143 µg g-1 BPA, 150 µg g-1 LIN and 33 µg g-1 EE2. Results obtained suggest that radish is able to remove effectively the EDs in different conditions of salinity, pH and organic carbon content. Conclusions Although a certain phytotoxicity was observed in the treatments with NOM and both freshwaters added with EDs, radish germinating seeds showed a great ability to remove BPA, LIN and EE2 from different media. Therefore this study confirms the great potential of phytoremediation as an environmental-friendly technology able to remove EDs from real aqueous systems. Acknowledgements This study was financed by University of Bari, Italy and by Fundação de Amparo à Pesquisa do Estado de São Paulo- FAPESP (2009/13817-0). References 1
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