1.Vanillic and syringic acids from biomass burning: Behaviour during Fenton-like oxidation in atmospheric aqueous phase and in the absence of light.
Santos GT1, Santos PS2, Duarte AC1. J Hazard Mater. 2016 Apr 7;313:201-208. doi: 10.1016/j.jhazmat.2016.04.006. [Epub ahead of print]
Biomass combustion is a threat to the environment since it emits to the atmosphere organic compounds, which may react and originate others more aggressive. This work studied the behaviours of vanillic and syringic acids, small aromatic tracers of biomass burning, during Fenton-like oxidation in aqueous phase and absence of light. For both compounds, the extent of oxidation increased with pH decrease from neutral to acid in atmospheric waters, but for vanillic acid the neutral pH was not able of promoting the oxidation. With the oxidation of both acids were formed chromophoric compounds, and the formation rate increased with the degree of electron-donator substituents in benzene ring. The initial and produced compounds were not totally degraded up to 24h of reaction at pH 4.5, suggesting that the night period may be not sufficient for their full degradation in atmospheric waters. The major compounds formed were the 3,4-dihydroxybenzoic acid for vanillic acid, and the 1,4-dihydroxy-2,6-dimethoxybenzene for syringic acid.
2.Ultra-trace graphene oxide in a water environment triggers Parkinson's disease-like symptoms and metabolic disturbance in zebrafish larvae.
Ren C1, Hu X2, Li X3, Zhou Q4. Biomaterials. 2016 Mar 31;93:83-94. doi: 10.1016/j.biomaterials.2016.03.036. [Epub ahead of print]
Over the past decade, the safety of nanomaterials has attracted attention due to their rapid development. The relevant health threat of these materials remains largely unknown, particularly at environmentally or biologically relevant ultra-trace concentrations. To address this, we first found that graphene oxide (GO, a carbon nanomaterial that receives extensive attention across various disciplines) at concentrations of 0.01 μg/L-1 μg/L induced Parkinson's disease-like symptoms in zebrafish larvae. In this model, zebrafish showed a loss of more than 90% of dopamine neurons, a 69-522% increase in Lewy bodies (α-synuclein and ubiquitin) and significantly disturbed locomotive activity. Moreover, it was also shown that GO was able to translocate from the water environment to the brain and localize to the nucleus of the diencephalon, thereby inducing structural and morphological damage in the mitochondria. Cell apoptosis and senescence were triggered via oxidative stress, as shown by the upregulation of caspase 8 and β-galactosidase.
3.Chlorination of oxybenzone: Kinetics, transformation, disinfection byproducts formation, and genotoxicity changes.
Zhang S1, Wang X1, Yang H2, Xie YF3. Chemosphere. 2016 Apr 13;154:521-527. doi: 10.1016/j.chemosphere.2016.03.116. [Epub ahead of print]
UV filters are a kind of emerging contaminant, and their transformation behavior in water treatment processes has aroused great concern. In particular, toxic products might be produced during reaction with disinfectants during the disinfection process. As one of the most widely used UV filters, oxybenzone has received significant attention, because its transformation and toxicity changes during chlorine oxidation are a concern. In our study, the reaction between oxybenzone and chlorine followed pseudo-first-order and second-order kinetics. Three transformation products were detected by LC-MS/MS, and the stability of products followed the order of tri-chloro-methoxyphenoyl > di-chlorinated oxybenzone > mono-chlorinated oxybenzone. Disinfection byproducts (DBPs) including chloroform, trichloroacetic acid, dichloroacetic acid and chloral hydrate were quickly formed, and increased at a slower rate until their concentrations remained constant.
4.Effect of alkyl polyglucoside and nitrilotriacetic acid combined application on lead/pyrene bioavailability and dehydrogenase activity in co-contaminated soils.
Chen T1, Liu X2, Zhang X1, Chen X1, Tao K1, Hu X1. Chemosphere. 2016 Apr 13;154:515-520. doi: 10.1016/j.chemosphere.2016.03.127. [Epub ahead of print]
At present, few research focus on the phytoremediation for organic pollutants and heavy metals enhanced by surfactants and chelate agents in the combined contaminated soils or sediments. In this study, the effect of a novel combined addition of alkyl polyglucoside (APG) and nitrilotriacetic acid (NTA) into pyrene and lead (Pb) co-contaminated soils on bioaccessiblity of pyrene/Pb and dehydrogenase activities (DHA) was studied. Through the comparison of the results with the alone and combined application, synergistic effect on bioaccessiblity of pyrene and Pb was found while APG and NTA was applied together. Results also indicated a significant promotion on the DHA in mixed addition of APG and NTA. In addition, correlation and principal component analysis were performed to better understand the relationship among APG/NTA, bioaccessiblity of pyrene/Pb and the DHA. Results showed that APG and NTA can affect DHA directly by themselves but also can affect DHA indirectly by changing bioaccessible pyrene and exchangeable Pb.