Effects of gamma radiation on cork wastewater: Antioxidant activity and toxicity

Abstract

a b s t r a c tA comprehensive assessment of the toxicity and antioxidant activity of cork boiling wastewater and the effects of gamma radiation on these parameters was performed. Antioxidant activity was evaluated using different methodologies as DPPH radical scavenging activity, reducing power and inhibition of b-carotene bleaching. The results have shown that gamma radiation can induce an increase on the antioxidant activity of cork boiling wastewater. Toxicity tests were performed to access the potential added value of the irradiated wastewaters and/or minimization of the impact for discharge in the environment. Two different methods for toxicity evaluation were followed, bacterial growth inhibition test and cytotoxicity assay, in order to predict the behavior of different cells (prokaryotic and eukaryotic) in the presence of cork wastewater. Non-treated cork boiling wastewater seemed to be non-toxic for prokaryotic cells (Pseudomonas fluorescens and Bacillus subtilis) but toxic for eukaryotic cells (A549 human cells and RAW264.7 mouse cells). The gamma radiation treatment at doses of 100 kGy appeared to increase the toxicity of cork compounds for all tested cells, which could be related to a toxic effect of radiolytic products of cork compounds in the wastewaters.

Oxidation of clofibric acid in aqueous solution using a non-thermal plasma discharge or gamma radiation

“…Irradiation experiments of clofibric acid solutions were carried out in an equipment previously described by Madureira et al (2017). The irradiation chamber was a cavity of stainless steel (50 cm depth, 20 cm width and 65 cm height) with four 60 Co sources placed in four channels on the side walls of the chamber.…”

Phenolic Compounds from Irradiated Olive Wastes: Optimization of the Heat-Assisted Extraction Using Response Surface Methodology

“…Ionizing radiation, a clean and environmentally friendly technology, has proven to be capable of improving phenolic extraction and antioxidant activity on industrial wastewater [16], fresh fruits such as cherry tomatoes [17], raspberries [18,19] and strawberries [20], and dried medicinal plants [21]. More recently, the potential of gamma radiation as an enhancer for phenolic compounds extraction and antioxidant capacity has been shown, with the application of low doses (5 kGy), enough to increase the extractability of the main phenolic compounds from olive pomace by 2.4-fold compared to non-irradiated samples [1].…”

The use of gamma radiation for extractability improvement of bioactive compounds in olive oil wastes

“…Recently, the scientific community has aroused considerable interest in the enhancement of beneficial properties by irradiation and in the ionizing radiation effects on bioactive compounds. Our previous studies have reported the use of this technology to improve phenolic content and antioxidant activity on industrial wastewater (Madureira et al, 2017), fresh fruits such as cherry tomatoes (Guerreiro et al, 2016) and raspberries (Cabo Verde et al, 2013), and dry medicinal plants (Pereira et al, 2017a), as well as its efficiency for decomposition of recalcitrant compounds (Madureira et al, 2018).…”