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141.
采用统计学及质量控制的一些基本理论及方法对污水处理厂的运行数据进行分析,得出城市污水处理厂BOD5、COD、SS、TN、TP等主要出水指标呈正态分布的规律;城市污水BOD5、COD、TN、TP等指标间存在显著线性相关性的结论.研究结论可用于污水处理厂制定经济合理的出水监测方案以及对污水处理厂运行可靠性等进行评估. 相似文献
142.
143.
论我国非煤矿山安全生产标准体系构建思路 总被引:2,自引:3,他引:2
本文分析了我国目前非煤矿山安全生产标准体系建设的现状及存在的主要问题,阐述了建立一套科学、合理、完善的标准化体系对我国非煤矿山安全生产行业的重要意义;并根据非煤矿山安全生产标准体系建设的现状提出了我国非煤矿山安全生产标准体系建设的思路和基本框架,为今后非煤矿山安全生产标准体系建设提供一定基础。 相似文献
144.
Jeanne Clécia Alves Esther Lima de Paiva Raquel Fernanda Milani Eduardo Bearzoti Marcelo Antonio Morgano 《Journal of environmental science and health. Part. B》2017,52(6):418-424
Although fish is a healthy alternative for meat, it can be a vehicle for mercury (Hg), including in its most toxic organic form, methylmercury (MeHg). The objective of the present study was to estimate the risk to human health caused by the consumption of sushi and sashimi as commercialized by Japanese food restaurants in the city of Campinas (SP, Brazil). The total Hg content was determined by atomic absorption spectrometry with thermal decomposition and amalgamation, and the MeHg content calculated considering that 90% of the total Hg is in the organic form. The health risk was estimated from the values for the provisional tolerable weekly ingestion (PTWI) by both adults and children. The mean concentrations for total Hg were: 147.99, 6.13, and 3.42 µg kg?1 in the tuna, kani, and salmon sushi samples, respectively, and 589.09, 85.09, and 11.38 µg kg?1 in the tuna, octopus and salmon sashimi samples, respectively. The tuna samples showed the highest Hg concentrations. One portion of tuna sashimi exceeded the PTWI value for MeHg established for children and adults. The estimate of risk for human health indicated that the level of toxicity depended on the type of fish and size of the portion consumed. 相似文献
145.
细颗粒物(PM2.5)随空调新风进入室内,和室内产生的PM2.5粒子一起作用,导致人体暴露在室内细颗粒物环境中。为保证室内空气品质,最大限度节约空调系统运行能耗,建立了室内PM2.5浓度与CO2体积分数双组分模型,提出了适用于某会议室不同室内外PM2.5源、不同人数以及不同天气状况下的最佳通风策略,利用Simulink对炎热天气室内有无PM2.5散发源、温和天气室内有无PM2.5散发源4种工况下的不同通风方式进行仿真对比。模拟结果表明:炎热天气存在最小新风量,该值由室内人数决定,过滤送风对控制室内PM2.5浓度效果最好;温和天气存在最大新风量,且该值与过滤器效率成正比;在所研究的情况下,温和天气节能潜力比炎热天气大。 相似文献
146.
田湾核电站外围辐射环境监测工作的质量保证 总被引:1,自引:0,他引:1
总结了田湾核电站外围辐射环境监测中的质量保证实施情况,包括:人员培训和考核,仪器设备溯源,样品采集、运输、贮存及生物样品前处理的质控,样品分析和现场监测的质控,数据的记录处理和管理要求等,最后提出几点建议。 相似文献
147.
Klumpp A Ansel W Klumpp G Belluzzo N Calatayud V Chaplin N Garrec JP Gutsche HJ Hayes M Hentze HW Kambezidis H Laurent O Peñuelas J Rasmussen S Ribas A Ro-Poulsen H Rossi S Sanz MJ Shang H Sifakis N Vergne P 《Environmental science and pollution research international》2002,9(3):199-203
EuroBionet, the 'European Network for the Assessment of Air Quality by the Use of Bioindicator Plants', is an EU-funded cooperative project currently consisting of public authorities and scientific institutes from 12 cities in 8 countries. In 2000, the bioindicator plants tobacco (Nicotiana tabacum Bel W3), poplar (Populus nigra 'Brandaris'), spiderwort (Tradescantia sp. clone 4430), Italian rye grass (Lolium multiflorum italicum) and curly kale (Brassica oleracea acephala) were exposed to ambient air at 90 monitoring sites according to standardised methods. Visible injuries and growth parameters were assessed and the accumulation of toxic substances in leaves determined. The exposure of tobacco resulted in a gradient with low levels of ozone-induced foliar injury in N and NW Europe, and medium to high values in the southern and central regions. The results of heavy metal and sulphur analyses in rye grass samples generally showed low to very low sulphur and low to medium heavy metal concentrations in leaves. In some cities, however, local hot spots of heavy metal contamination were detected. Analyses of the PAH contents in curly kale leaves gave low to medium values, with locally elevated levels at traffic-exposed sites. 相似文献
148.
页岩气压裂返排液的有效处理是页岩气开发急需解决的关键环保问题之一。针对新页HF-1井页岩气压裂返排液经预氧化结合湿式氧化(PO-WAO)工艺处理的出水COD不达标、含盐量高等技术难题,采用膜蒸馏处理技术对工艺的出水进行深度处理。通过膜蒸馏单因素和正交实验表明料液温度和冷凝温度对膜蒸馏处理效果影响较大,在料液温度、冷凝液温度、真空度、运行时间分别为80℃、8℃、0.090 MPa和60 min的最佳工艺条件下,膜通量可达1.750 L·(m2·h)-1,出水COD浓度为95.8 mg·L-1,出水水质可满足《污水综合排放标准》(GB 8978-1996)中一级排放的要求。膜蒸馏出水中电导率为63 μS·cm-1,氯化钠的质量浓度为1.168 0 mg·L-1,可有效降低处理后的压裂废液对周围土壤的盐碱化伤害。 相似文献
149.
150.
J. S. Gaffney N. A. Marley M. M. Cunningham P. V. Doskey 《Atmospheric environment (Oxford, England : 1994)》1999,33(30):10265
Peroxyacyl nitrates (PANs) were measured using gas chromatography with electron capture detection (GC/ECD) in north central Mexico City during February–March of 1997. Peroxyacetyl nitrate (PAN) was observed to exceed 30 ppb during five days of the study, with peroxypropionyl nitrate (PPN) and peroxybutryl nitrate (PBN) reaching 6 and 1 ppb maximum, respectively. Levels of total PANs typically exceeded 10 ppb during the period of measurement and showed a very strong diurnal variation with PANs maximum during the early afternoon and falling to less than 0.1 ppb during the evening hours. These levels of PANs are the highest reported values in North America (and the world) for an urban center, since levels of approximately 30 ppb were reported during the late 1970s in the Los Angeles area (South Coast Air Basin, Tuazon et al., 1978). Hydrocarbon measurements indicate that the levels of olefins, specifically butenes are significant in Mexico City. A time series taken of source indicator hydrocarbons taken before and during a Mexican National Holiday with reduced automobile traffic clearly show that mobile sources of butenes are as important as liquefied petroleum gas. Observations of 10–40 ppb C methyl-t-butyl ether (MTBE) are consistent with MTBE/gasoline fuel usage as a source of isobutene and formaldehyde. Both these reactive species can lead to increased oxidant and PAN formation. The strong diurnal profiles of PANs are consistent with regional clearing of the Mexico City air basin on a daily basis. Estimates are given using a simple box model calculation for a number of key primary and secondary pollutant emissions from this megacity on an annual basis. These calculations indicate that megacities can be important sources of both primary and secondary pollutants, and that PANs produced in megacity environments are likely to contribute strongly to regional scale ozone and aerosol productions during long range transport. 相似文献