University of Texas
30 March 2015
22 June 2015
13 December 2015
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Science in the News
Latest on-line papers from the SEGH journal: Environmental Geochemistry and Health
- Pollution profiles and risk assessment of PBDEs and phenolic brominated flame retardants in water environments within a typical electronic waste dismantling region 2014-12-14
The aim of this study was to assess the pollution profiles of various typical brominated flame retardants in water and surface sediment near a typical electronic waste dismantling region in southern China. We found that polybrominated diphenyl ethers (PBDEs), 2,4,6-tribromophenol (TBP), pentabromophenol (PeBP), tetrabromobisphenol A (TBBPA), and bisphenol A (BPA) were ubiquitous in the water and sediment samples collected in the study region. In water, ÎŁ19PBDEs (sum of all 20 PBDE congeners studied except BDE-209, which was below the detection limit) levels ranged from 0.31 to 8.9Â ĂÂ 102Â ngÂ Lâ1. TBP, PeBP, TBBPA, and BPA concentrations in the water samples ranged from not being detectable (ndâunder the detection limit) to 3.2Â ĂÂ 102 (TBP), from nd to 37 (PeBP), from nd to 9.2Â ĂÂ 102 (TBBPA) and from ndâ8.6Â ĂÂ 102 ng Lâ1 (BPA). In sediment, ÎŁ19PBDEs ranged from nd to 5.6Â ĂÂ 103 ngÂ gâ1, while BDE-209 was the predominant congener, with a range of nd to 3.5Â ĂÂ 103 ngÂ gâ1. Tri- to hepta-BDE concentrations were significantly (pÂ <Â 0.01) correlated with each other, except for BDE-71 and BDE-183, and octa- to nona-BDEs concentrations were significantly (pÂ <Â 0.05) correlated with each other, except for BDE-208. BDE-209 was not significantly correlated with tri- to nona-BDEs. Risk assessments indicated that the water and sediment across the sampling sites posed no estrogenic risk. However, different eco-toxicity risk degrees at three trophic levels did exist at most sampling sites.
- Particle size distribution and air pollution patterns in three urban environments in Xiâan, China 2014-12-13
Three urban environments, office, apartment and restaurant, were selected to investigate the indoor and outdoor air quality as an inter-comparison in which CO2, particulate matter (PM) concentration and particle size ranging were concerned. In this investigation, CO2 level in the apartment (623Â ppm) was the highest among the indoor environments and indoor levels were always higher than outdoor levels. The PM10 (333Â Â”g/m3), PM2.5 (213Â Â”g/m3), PM1 (148Â Â”g/m3) concentrations in the office were 10â50Â % higher than in the restaurant and apartment, and the three indoor PM10 levels all exceeded the China standard of 150Â Â”g/m3. Particles ranging from 0.3 to 0.4Â Â”m, 0.4 to 0.5Â Â”m and 0.5 to 0.65Â Â”m make largest contribution to particle mass in indoor air, and fine particles number concentrations were much higher than outdoor levels. Outdoor air pollution is mainly affected by heavy traffic, while indoor air pollution has various sources. Particularly, office environment was mainly affected by outdoor sources like soil dust and traffic emission; apartment particles were mainly caused by human activities; restaurant indoor air quality was affected by multiple sources among which cooking-generated fine particles and the human steam are main factors.
- Comparison of physical and chemical properties of ambient aerosols during the 2009 haze and non-haze periods in Southeast Asia 2014-12-13
Recurrent smoke-haze episodes that occur in Southeast Asia (SEA) are of much concern because of their environmental and health impacts. These haze episodes are mainly caused by uncontrolled biomass and peat burning in Indonesia. Airborne particulate matter (PM) samples were collected in the southwest coast of Singapore from 16 August to 9 November in 2009 to assess the impact of smoke-haze episodes on the air quality due to the long-range transport of biomass and peat burning emissions. The physical and chemical characteristics of PM were investigated during pre-haze, smoke-haze, and post-haze periods. Days with PM2.5 mass concentrations of â„35Â ÎŒgÂ mâ3 were considered as smoke-haze events. Using this criterion, out of the total 82 sampling days, nine smoke-haze events were identified. The origin of air masses during smoke-haze episodes was studied on the basis of HYSPLIT backward air trajectory analysis for 4Â days. In terms of the physical properties of PM, higher particle surface area concentrations and particle gravimetric mass concentrations were observed during the smoke-haze period, but there was no consistent pattern for particle number concentrations during the haze period as compared to the non-haze period except that there was a significant increase at about 08:00, which could be attributed to the entrainment of PM from aloft after the breakdown of the nocturnal inversion layer. As for the chemical characteristics of PM, among the six key inorganic water-soluble ions (Clâ, NO3 â, nss-SO4 2â, Na+, NH4 +, and nss-K+) measured in this study, NO3 â, nss-SO4 2â, and NH4 + showed a significant increase in their concentrations during the smoke-haze period together with nss-K+. These observations suggest that the increased atmospheric loading of PM with higher surface area and increased concentrations of optically active secondary inorganic aerosols [(NH4)2SO4 or NH4HSO4 and NH4NO3] resulted in the atmospheric visibility reduction in SEA due to the advection of biomass and peat burning emissions.