State of art control of dioxins/unintentional POPs in the secondary copper industry: A review to assist policy making with the implementation of the Stockholm Convention

Article 5 of the Stockholm Convention requires that each Party shall take measures to reduce the releases from anthropogenic sources of unintentional persistent organic pollutants(UPOPs),with the goal of their continuing minimization and,where feasible,their ultimate elimination.A major source of polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs)and other unintentional POPs releases,both in China and worldwide,is the metal industry in particular secondary metal industries such as copper smelting.More than 50%of the global secondary copper production is now in China and high levels of PCDD/Fs are released from these operations with the national inventory of China reporting a total of 1133.8 g toxic equivalents(TEQ)yr1.Consequently the Global Environment Facility(GEF)is supporting the project‘UPOPs Reduction through best available techniques and best environmental practices(BAT/BEP)in the secondary copper production sector’in China compromising>50%of the global secondary copper production.As part of this project,information on relevant UPOPs from the metal industry have been reviewed and is presented here.This information should also be useful for other(developing)countries for controlling UPOPs releases from metal industries.This review and the information it contains provides a robust resource for policy makers,the industry and researchers to improve secondary copper production to BAT/BEP standards in relation to the reduction of PCDD/Fs and other UPOPs release.The contents include the details required to assist the understanding of the formation of chlorinated UPOPs along with their brominated and brominated-chlorinated analogues.It reviews the international sources of information on BAT/BEP,including the integrated approach considered in the European BAT Reference document,and shows how this can be used to achieve an overall reduction of pollutant releases from the industry.The current national standards of PCDD/F limits to air,water and solid residues have been compiled and are also included.Challenges which need to be addressed,such as the current international lack to consider brominated and mixed bromo-chloro PXDD/Fs which might be more environmentally significant than PCDD/Fs in some facilities e are also discussed.The study includes a brief description of the steps China has taken to change the national regulatory framework and to improve the sustainability of its secondary metal industry.The Stockholm Convention BAT/BEP guidelines recommend consideration of integrated pollution prevention and control and sustainable production as general principles which parties may incorporate when applying the BAT/BEP guidelines and guidance.This holistic approach is considered in the current project and in the improvement of the pilot facilities and will also be considered in the replication of experiences in other facilities.Using this approach ensures the implementation of the Stockholm Convention can contribute to integrated pollution prevention and control,the development of a circular economy and consequently to genuinely sustainable development thus contributing to different sustainable development goals(SDGs).It is hoped this approach will be adopted in other developing and transition economies and thus help to achieve improvements of the secondary metal industry globally.

Delphinidin-3-O-sambubioside: a novel xanthine oxidase inhibitor identified from natural anthocyanins

Objectives:This study was conducted to investigate the xanthine oxidase(XO)inhibitory activities of 18 monomeric anthocyanins from berry fruits and roselle,and to illustrate the underlying mechanism of the most active anthocyanin delphinidin-3-O-sambubioside.Materials and Methods:Eighteen monomeric anthocyanins were prepared and purified in our laboratory.The inhibitory properties of anthocyanins were investigated by in vitro inhibitory activity studies and fluorescence quenching studies;the inhibitory mechanism was explored through kinetic studies,fluorescence quenching studies,circular dichroism analysis and computational docking simulations.Results:XO inhibitory activities of anthocyanins were related to the structures of B rings and glycosides.Among all the tested anthocyanins,delphinidin-3-O-sambubioside showed the most potent inhibitory activity with an IC_(50) of 17.1μmol/L,which was comparable to the positive control allopurinol.Spectroscopic results revealed that delphinidin-3-O-sambubioside could spontaneously interact with XO and induce conformational changes.Computational docking study indicated that delphinidin-3-O-sambubioside could bind to XO with a proper orientation,stably formed π-π interactions and hydrogen bonds with key residues,thus preventing the substrate from entering the active pocket.Conclusions:In brief,our study identified delphinidin-3-O-sambubioside as a potent XO inhibitor from natural anthocyanins,which is potentially applicable for prevention and treatment of hyperuricemia.