Preparation of SiO_2@Au nanorod array as novel surface enhanced Raman substrate for trace pollutants detection

An effective surface enhanced Raman scattering（SERS） substrate is designed and fabricated by synthesis of Si O2 nanorods array via glancing angle deposition, followed by coating Au nanoparticles onto Si O2 surface in order to create numerous ＂hot spots＂. The detecting sensitivity of such substrate could be optimized by simply adjusting the deposition time of Au. Thus, it can be used for detection of Rhodamine 6G at concentration as low as 10^-9M. Furthermore, our SERS substrate is applied to detect 5 μg/g polychlorinated biphenyls in soil sample, which proves its potential for trace environmental pollutants detection.

Unveiling the existence and ecological hazards of trace organic pollutants in wastewater treatment plant effluents across China

The presence of trace organic pollutants in the effluent of wastewater treatment plants(WWTPs)poses considerable risks to aquatic organisms and human health.A large-scale survey of 302 trace organic pollutants in the effluent of 46 Chinese WWTPs was conducted to gain an improved understanding of their occurrence and ecological risks.The survey data showed that 216 compounds in 11 chemical classes had been detected in effluents.The sum concentrations of the trace contaminants in effluent ranged from 1,392 ng/L to 35,453 ng/L,with the maximum concentration of perfluoroalkyl substances(PFASs)recorded as the highest(30,573 ng/L),which was markedly less than the reported 185,000 ng/L for the 38 American WWTPs.The concentration of bisphenol analogs(BPs)was up to 4,422 ng/L,significantly higher than those reported in France,Germany,Japan,Korea,and the U.S.PFASs and BPs were the major pollutants,accounting for 59%of the total pollution.Additionally,a total of 119 contaminants were found to have ecological risks(RQ>0.01).Among these,23 contaminants(RQ>1.0)warrant higher attention and should be prioritized for removal.This study lists valuable information for controlling contaminants with higher priority in WWTP effluent in China.

Fate and risk assessment of emerging contaminants in reclaimed water production processes

Reclaimed water has been widely applied in irrigation and industrial production.Revealing the behavior of emerging contaminants in the production process of reclaimed water is the first prerequisite for developing relevant water quality standards.This study investigated 43 emerging contaminants,including 22 pharmaceuticals and personal care products(PPCPs),11 organophosphorus flame retardants(OPFRs),and 10 antibiotic resistance genes(ARGs)in 3 reclaimed wastewater treatment plants(RWTPs)in Beijing.The composition profiles and removal efficiencies of these contaminants in RWTPs were determined.The results indicated that the distribution characteristics of the different types of contaminants in the three RWTPs were similar.Caffeine,sul2 and tris(1-chloro-2-propyl)phosphate were the dominant substances in the wastewater,and their highest concentrations were 27104 ng/L,1.4×10^(7) copies/mL and 262 ng/L,respectively.Ofloxacin and sul2 were observed to be the dominant substances in the sludge,and their highest concentrations were 5419 ng/g and 3.7×10^(8) copies/g,respectively.Anaerobic/anoxic/oxic system combined with the membrane bioreactor process achieved a relatively high aqueous removal of PPCPs(87%).ARGs and OPFRs were challenging to remove,with average removal rates of 6.5%and 31%,respectively.Quantitative meta-analysis indicated that tertiary treatment processes performed better in emerging contaminant removal than secondary processes.Diethyltoluamide exhibited the highest mass load discharge,with 33.5 mg/d per 1000 inhabitants.Octocrylene and tris(2-ethylhexyl)phosphate posed high risks(risk quotient>1.0)to aquatic organisms.This study provides essential evidence to screen high priority pollutants and develop corresponding standard in RWTPs.

Large inter annual variation in air quality during the annual festival ‘Diwali' in an Indian megacity

A network of air quality and weather monitoring stations was established under the System of Air Quality Forecasting and Research（SAFAR） project in Delhi. We report observations of ozone（O_3）, nitrogen oxides（NO_x）, carbon monoxide（CO） and particulate matter（PM_2.5and PM_（10）） before, during and after the Diwali in two consecutive years, i.e., November 2010 and October 2011. The Diwali days are characterised by large firework displays throughout India. The observations show that the background concentrations of particulate matter are between 5 and 10 times the permissible limits in Europe and the United States. During the Diwali-2010, the highest observed PM_（10） and PM_2.5mass concentration is as high as2070 μg/m^3 and 1620 μg/m3, respectively（24 hr mean）, which was about 20 and 27 times to National Ambient Air Quality Standards（NAAQS）. For Diwali-2011, the increase in PM_（10） and PM_2.5mass concentrations was much less with their peaks of 600 and of 390 μg/m^3 respectively, as compared to the background concentrations. Contrary to previous reports,firework display was not found to strongly influence the NO_x, and O_3 mixing ratios, with the increase within the observed variability in the background. CO mixing ratios showed an increase. We show that the large difference in 2010 and 2011 pollutant concentrations is controlled by weather parameters.