城市污水处理厂的大气污染治理技术

城市污水处理厂在污水处理的过程中会产生一些大气污染。我们应弄清这些污染的成分和来源并加以控制以免形成二次污染,防止给周边环境尤其是居民的居住、工作环境造成影响。介绍近年来国内外学者就城市污水处理厂的大气污染问题的最新研究成果,并调查了青岛市两个典型污水处理厂的大气污染情况,展现了当前城市污水处理厂的大气污染的研究现状。     

生物强化技术处理化纤废水

采用生物强化技术,即利用从废水中分离、筛选出的降解丙烯腈与总氰的特效菌株,使化纤废水加营养盐的培养基中丙烯腈降解率达98．7％,总氰降解率达84％。将分离到的特效菌株进行混合培养,其降解丙烯腈与总氰的最佳体积比为1．0：（1．5～2．0）。使用该技术不必改变化纤废水处理场原有工艺。     

长江口江苏段长江江豚种群监测

长江口江苏段为江阴大桥至长江口北支入海口,受海洋潮汐影响较大,是长江江豚（Neophocaena asiaeorientalis）最下游分布区。为掌握该区域长江江豚种群数量和分布状况,于2023年进行了4次船只目视调查,并于2019年12月—2023年12月采用定点观测、环境DNA（eDNA）监测等方法进行监测。结果显示,2019年12月—2023年12月,累计观测到长江江豚236次,718头次。江阴大桥至崇启大桥,两岸均有长江江豚分布,热点区域为五山江段、常阴沙江段和江阴大桥江段。4次船只目视调查（样线1 274 km）共目击到长江江豚28次,计65头次。长江江豚的遇见率为0.02~0.13头次/km,平均遇见率为0.05头次/km。可见系数法估算结果得到2,5,9,11月该江段种群数量为14.8~64.8头,平均为38.9头。长江江豚冬、春季较为活跃。长江江豚热点区域自然岸线相对较多,人为活动干扰较小。针对长江口江苏段无专门长江江豚保护地,缺乏系统监测与保护措施等问题,提出应完善监测体系、加大保护力度、将长江江豚热点活动区域作为重点监护区以及建立长江江豚自然保护区等建议。     

Tourism’s Impacts on Natural Resources: A Positive Case from China

Tourism development may result in negative impacts on natural resources owing to overuse and mismanagement. However, tourism may also play positive roles in natural resource conservation, which has rarely been verified in practice, although some researchers have demonstrated this in theory. In this article, taking the Jiuzhaigou Biosphere Reserve as a case study area, we conducted an analysis for the environmental impacts from tourism development based on social survey and interpretation of remote sensing images. The results show that the natural environment was not degraded and some indicators are even improving because all the residents have participated in tourism and given up farming and hunting. It is concluded that it is possible to use tourism as a way to balance natural resource conservation and economic development under the preconditions of making effective policies to encourage and help local people participate in tourism business and to benefit from it.     

Comparison of manual and automated chambers for field measurements of N2O,CH4, CO2 fluxes from cultivated land

Chamber techniques can easily be applied to field trials with multiple small plots measuring carbon- and nitrogen-trace gas fluxes. Nevertheless, such chamber measurements are usually made weekly and rarely more frequently than once daily. However, automatic chambers do allow flux measurements on sub-daily time scales. It has been hypothesized that sub-daily measurements provide more reliable results, as diurnal variations are captured better compared to manual measurements. To test this hypothesis we compared automatic and manual measurements of N₂O, CO₂ and CH₄ fluxes from tilled and non-tilled plots of a rice–wheat rotation ecosystem over a non-waterlogged period. Our results suggest that both techniques, i.e., either manual or automatic chambers of N₂O and CO₂ emissions resulted in biased fluxes. The manual measurements were adequate to capture either day-to-day or seasonal dynamics of N₂O, CO₂ and CH₄ exchanges, but overestimated the cumulative N₂O and CO₂ emissions by 18% and 31%, respectively. This was due to neglecting temperature-dependent diurnal variations of C and N trace gas fluxes. However, the automatic measurements underestimated the cumulative emissions of N₂O and CO₂ by 22% and 17%, respectively. This underestimation resulted from chamber effects upon soil moisture during rainfall processes. No significant difference was detected between the two methods in CH₄ exchanges over the non-waterlogged soils. The bias of manual chambers may be significant when pronounced diurnal variations occur. The bias of automatic measurements can only be avoided/minimized if chamber positions are frequently changed and/or if chambers are automatically opened during rainfall events. We therefore recommend using automatic chambers together with continuous measurements of soil chamber moisture to allow for soil moisture correction of fluxes or to correct flux estimates as derived by manual chambers for possible diurnal variations.     

Photocatalytic debromination of preloaded decabromodiphenyl ether on the TiO(2) surface in aqueous system

There have been serious concerns about polybromodiphenyl ethers (PBDEs) in the environment because of their global distribution and bioaccumulation. Owing to strong hydrophobicity of PBDEs, the regular photocatalytic system, in which the substrate is solvated in the bulk solution, is not applicable to the removal of the PBDEs in water. In this work, the photocatalytic reduction degradation of decabromodiphenyl ether (BDE209), the most-used PBDEs, was investigated in aqueous system, by pre-adsorbing it on the surface of photocatalyst. It was found that the preloaded BDE209 underwent efficient reductive debromination in aqueous system under irradiation with wavelength larger than 360 nm in the presence of electron donors such as methanol. Our experiments further show that such a preloaded system exhibits different characteristics from that in the organic solution. The meta-debrominated intermediate is predominant in the present system, while the ortho-debrominated one is the main nona-BDE products in the organic solution. In addition, different from other photocatalytic system, the pH has little effect on the photocatalytic reaction. We propose that these differences are originated from the formation of overlayer of hydrophobic BDE209 to limit the motion of BDE209 and the access of water and H⁺/OH⁻ to the TiO₂ surface.     

The impact of transportation control measures on emission reductions during the 2008 Olympic Games in Beijing,China

Traffic congestion and air pollution were two major challenges for the planners of the 2008 Olympic Games in Beijing. The Beijing municipal government implemented a package of temporary transportation control measures during the event. In this paper, we report the results of a recent research project that investigated the effects of these measures on urban motor vehicle emissions in Beijing. Bottom–up methodology has been used to develop grid-based emission inventories with micro-scale vehicle activities and speed-dependent emission factors. The urban traffic emissions of volatile organic compounds (VOC), carbon monoxide (CO), nitrogen oxides (NO_x) and particulate matter with an aerodynamic diameter of 10 μm or less (PM₁₀) during the 2008 Olympics were reduced by 55.5%, 56.8%, 45.7% and 51.6%, respectively, as compared to the grid-based emission inventory before the Olympics. Emission intensity was derived from curbside air quality monitoring at the North 4th Ring Road site, located about 7 km from the National Stadium. Comparison between the emission intensity before and during the 2008 Olympics shows a reduction of 44.5% and 49.0% in daily CO and NO_x emission from motor vehicles. The results suggest that reasonable traffic system improvement strategies along with vehicle technology improvements can contribute to controlling total motor vehicle emissions in Beijing after the Olympic Games.     

Performance of the emerging biochar on the stabilization of potentially toxic metals in smelter- and mining-contaminated soils

Environmental Science and Pollution Research - Soil potentially toxic metals (PTMs) pollution caused by anthropogenic activities has become serious concern with respect to the crop safety...     

The association between air pollutants and autism spectrum disorders

Autism spectrum disorders are a member of the pervasive developmental disorders (PDDs) that have been increasing dramatically since described by Leo Kanner in 1943. In the past decade, the number of epidemiological publications addressing air pollution exposures and autism has grown correspondingly, but the association is still unclear. Whether air pollutants play a causal role and which substances are related with autism requires further study. We systematically reviewed the literature from 2005 to 2016 in MEDLINE (National Library of Medicine), Web of Science, and PubMed and summarized the association between different air pollutants and autism. Furthermore, we further discussed the exposure time window and potential confounders that should be considered in the association analysis studies. Our objective is to summarize the association between different air pollutants and autism with literature, which has been published since 2005, and explore whether the exposure time window and potential confounders have influence on this association. These results could provide more comprehensive information about the association between air pollutants and autism and be helpful towards further validation study.

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