Decontamination activity of ryegrass exudates towards bisphenol A in the absence and presence of dissolved natural organic matter.

Bisphenol A (BPA) is an endocrine disruptor compound widespread in terrestrial and aquatic systems of urbanized and industrialized regions. This study evaluated the capacity of ryegrass (Lolium perenne) aqueous exudates to degrade BPA at a concentration of 10 mg L(-1) both in the absence and in the presence of an organic fraction often coexisting with plant exudates, i.e., natural organic matter (NOM), tested at a concentration of 20 mg L(-1). In exudates alone, BPA degradation ceased after one day from the product addition when residual BPA resulted 65% of the initial BPA, whereas in exudates with the addition of NOM the degradation process continued for 4 days when residual BPA resulted 49%. Measurements of peroxidase and laccase activities in exudates suggested a significant involvement of these enzymes in BPA degradation. This finding was further confirmed by the almost complete absence of BPA degradation in aqueous exudates strongly acidified. In some BPA-contaminated exudates, chromatographic analysis revealed the presence of a newly formed compound identified as a BPA oxidation product by Fourier transform - ion cyclotron resonance mass spectrometry analysis. In conclusion, ryegrass exudates possess a relevant decontamination capacity towards BPA which persists and appears to be enhanced by the addition of NOM.

Removal of a combination of endocrine disruptors from aqueous systems by seedlings of radish and ryegrass.

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.

Biodecontamination of aqueous substrates from bisphenol A by ligninolytic fungi.

Bisphenol A (BPA) is an endocrine disruptor compound of health concern in natural systems. In this study, BPA removal from solid and aqueous matrices by ligninolytic fungi was investigated. Three white rot fungi, Trametes versicolor (TRA), Stereum hirsutum (STE) and Pleurotus ostreatus (PLE) were evaluated for their capacity to remove BPA added at concentrations of 4.6 and 46 mg L(-1) from potato dextrose agar (PDA) growth medium and at 4.6 mg L(-1) from aqueous solutions. Further, the inhibition of mycelial growth exerted by BPA was evaluated in the experiments with PDA. Results obtained showed that BPA was toxic for TRA and STE only at the higher concentration in PDA. However, the efficiency of the three fungi for BPA removal was significant at either doses, with TRA showing the maximum removal efficiency. In the experiments in aqueous solutions BPA was removed efficiently only by TRA after 7 days and STE after 10 days.

Removal of bisphenol A by the freshwater green alga Monoraphidium braunii and the role of natural organic matter.

Phytoremediation of waters by aquatic organisms such as algae has been recently explored for the removal of organic pollutants possessing endocrine disrupting capacity. Monoraphidium braunii, a green alga known for rapid growth and good tolerance to different natural organic matter (NOM) qualities, was tested in this study for the ability to tolerate and remove the endocrine disruptor bisphenol A at concentrations of 2, 4 and 10mgL(-1), either in NOM-free or NOM-containing media. NOM at concentrations of 2, 5 and 20mgL(-1) of DOC, was added because it may interfere with xenobiotics and modify their effects, modulate algal growth performances or produce a trade-off of both effects. After 2 and 4 days of algal growth, the cell number and size, the maximum quantum yield of photosystem II in the dark or light adapted state, and the chlorophyll a content were recorded in order to evaluate the algal response to bisphenol A. Moreover, the residual bisphenol A was measured in the algal cultures by chromatographic technique. Results indicated that after 2 and 4 days bisphenol A at the lower concentrations was not toxic for alga, whereas at the highest concentration it reduced algal growth and photosynthetic efficiency. The sole NOM and its combinations with bisphenol A at the lower concentrations increased the cell number and the chlorophyll a content of algae. After 4-day growth, good removal efficiency was exerted by M. braunii at concentrations of 2, 4 and 10mgL(-1) removing, respectively, 39%, 48% and 35% of the initial bisphenol A. Lower removal percentages were found after 2-day growth in the different treatments. NOM at any concentration scarcely influenced the bisphenol A removal. On the basis of data obtained, the use of M. braunii could be reasonably recommended for the phytoremediation of aquatic environments from bisphenol A.