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101.
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本文以广州市区和电子垃圾拆解区室内灰尘为研究对象,分析不同粒径(50—2000μm)灰尘中溴代阻燃剂(brominated flame retardants, BFRs)的浓度、组成和生物有效性.广州市区灰尘中BFRs以十溴二苯乙烷(decabromodiphenyl ethane, DBDPE)(4930—7280 ng·g~(-1))为主,电子垃圾拆解区以十溴联苯醚(polybrominated diphenyl ether 209, BDE209)(5570—602600 ng·g~(-1))为主.对比研究结果发现,城市灰尘中BFRs的分布无粒径差异,而电子垃圾拆解区最细粒径灰尘中BFRs含量最高.广州市区灰尘中BFRs生物有效性随化合物的lg K_(ow)增加而降低.电子垃圾拆解区灰尘生物有效性显著低于市区灰尘,表明在电子垃圾拆解区灰尘中电子垃圾碎片的存在很大程度上降低了BFRs的生物有效性.人体暴露评估结果显示,广州市区人体暴露风险低于电子垃圾拆解区暴露风险. 相似文献
103.
Xiaobo Liu 《Journal of the Air & Waste Management Association (1995)》2013,63(7):837-843
The U.S. Environmental Protection Agency’s (EPA) Motor Vehicle Emission Simulator (MOVES) is required by the EPA to replace Mobile 6 as an official on-road emission model. Incorporated with annual vehicle mile traveled (VMT) by Highways Performance Monitoring System (HPMS) vehicle class, MOVES allocates VMT from HPMS to MOVES source (vehicle) types and calculates emission burden by MOVES source type. However, the calculated running emission burden by MOVES source type may be deviated from the actual emission burden because of MOVES source population, specifically the population fraction by MOVES source type in HPMS vehicle class. The deviation is also the result of the use of the universal set of parameters, i.e., relative mileage accumulation rate (relativeMAR), packaged in MOVES default database. This paper presents a novel approach by adjusting the relativeMAR to eliminate the impact of MOVES source population on running exhaust emission and to keep start and evaporative emissions unchanged for both MOVES2010b and MOVES2014. Results from MOVES runs using this approach indicated significant improvements on VMT distribution and emission burden estimation for each MOVES source type. The deviation of VMT by MOVES source type is minimized by using this approach from 12% to less than 0.05% for MOVES2010b and from 50% to less than 0.2% for MOVES2014 except for MOVES source type 53. Source type 53 still remains about 30% variation. The improvement of VMT distribution results in the elimination of emission burden deviation for each MOVES source type. For MOVES2010b, the deviation of emission burdens decreases from ?12% for particulate matter less than 2.5 μm (PM2.5) and ?9% for carbon monoxide (CO) to less than 0.002%. For MOVES2014, it drops from 80% for CO and 97% for PM2.5 to 0.006%.Implications: This approach is developed to more accurately estimate the total emission burdens using EPA’s MOVES, both MOVES2010b and MOVES2014, by redistributing vehicle mile traveled (VMT) by Highways Performance Monitoring System (HPMS) class to MOVES source type on the basis of comprehensive traffic study, local link-by-link VMT broken down into MOVES source type. 相似文献
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The biosorption of lead(II) ions in both simulated and real wastewater by spent mushroom Tricholoma lobayense, was studied in this work. The results show a biomass with a high potential for removing lead ions from wastewater. The optimum pH for the adsorption is 4, and the adsorption process is fast. The best sorbent mass of the biomaterial is 5 g/L with an initial lead(II) concentration of 1 mmol/L. The process follows the Langmuir isotherm model, and the biosorption capacity of lead ions reaches to 210 mg/g, which is higher than many biosorbents previously studied. The mechanism of biosorption may be mainly attributed to ion exchange. The FT-IR study identifies the functional groups responsible for this process. A scanning electron microscope showed a significant change of the sorbent surface after the biosorption process. The energy dispersive elemental analysis also confirmed the adsorption of lead(II) ions. 相似文献
106.
Rothenberg SE Feng X Dong B Shang L Yin R Yuan X 《Environmental pollution (Barking, Essex : 1987)》2011,159(5):1283-1289
In China, total Hg (HgT) and methylmercury (MeHg) were quantified in rice grain grown in three sites using water-saving rice cultivation methods, and in one Hg-contaminated site, where rice was grown under flooded conditions. Polished white rice concentrations of HgT (water-saving: 3.3 ± 1.6 ng/g; flooded: 110 ± 9.2 ng/g) and MeHg (water-saving 1.3 ± 0.56 ng/g; flooded: 12 ± 2.4 ng/g) were positively correlated with root-soil HgT and MeHg contents (HgT: r2 = 0.97, MeHg: r2 = 0.87, p < 0.05 for both), which suggested a portion of Hg species in rice grain was derived from the soil, and translocation of Hg species from soil to rice grain was independent of irrigation practices and Hg levels, although other factors may be important. Concentrations of HgT and other trace elements were significantly higher in unmilled brown rice (p < 0.05), while MeHg content was similar (p > 0.20), indicating MeHg infiltrated the endosperm (i.e., white rice) more efficiently than inorganic Hg(II). 相似文献
107.
Tong Chen Xiaodong Li Jianhua Yan Shengyong Lu Kefa Cen 《Atmospheric environment (Oxford, England : 1994)》2011,45(36):6567-6575
Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were determined in fourteen ambient air samples collected in twelve cities of five provinces and one large municipality in China. The PCDD/F concentrations varied from 2.6 to 120 pg m−3 (or from 0.04 to 1.93 pg I-TEQ m−3). Generally, TCDF was the dominant homologue group and as a rule the homologue concentration of PCDF decreased with rising chlorine substitution number of PCDF. In all cases 2,3,4,7,8-PeCDF was the most important contributor to the I-TEQ value, accounting for 35–57% of the total I-TEQ value. Higher PCDD/F levels in ambient air were found during winter. The highest PCDD/F levels were found in Chengdu, Sichuan Province. In general, the PCDD/F levels in this study were in the same range as in other studies in China. 相似文献
108.
漆酶/HBT介质系统对靛蓝染料及废水脱色的初步研究 总被引:8,自引:0,他引:8
以云芝(Trametes versicolor)1126发酵所得漆酶粗酶液与1-羟基苯并三唑(HBT)组成的漆酶/HBT介质系统对靛蓝染料进行脱色实验,分别考察了温度、转速、pH和HBT与漆酶的加入量等条件对靛蓝染料脱色的影响.最终确定的优化脱色条件为:温度60℃,转速200r/min, pH4.5, 100mL靛蓝染料"溶液"中粗酶液和HBT溶液分别加入2mL.以上述脱色条件对靛蓝印染废水进行脱色实验,反应80min,脱色率可达90.1%. 相似文献
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110.
“十四五”时期是我国全面建成小康社会、实现第一个百年奋斗目标之后,乘势而上开启全面建设社会主义现代化国家新征程、向第二个百年奋斗目标进军的第一个五年,我国将进入新发展阶段。通过研究新发展阶段需求,分析生态环境监测存在的问题和短板,指出在职能转变、“减污降碳”、“真、准、全”等方面距离深入治污攻坚要求存在的差距,并以新发展理念为指导,研究提出生态环境监测体系与监测能力现代化建设的内涵实质、重要基础以及关键突破口,为加快构建生态环境监测新发展格局提供参考。 相似文献