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961.
This paper investigates the social costs of second-best agricultural greenhouse gas (GHG) mitigation policies. Adjustments along the land use and input intensity margins are represented within a regionalized optimization model of California crop production calibrated to economic and agronomic information. Second-best policies relying on spatially aggregated GHG emission factors lead to small abatement efficiency losses, while policies targeting a single GHG lead to moderate losses. In contrast, policies targeting a single input entail large abatement efficiency losses, which nonetheless can be reduced by combining instruments. 相似文献
962.
从热镀锌厂的酸洗废水和锌灰中回收硫化锌,采用X射线能谱仪(EDS),X射线衍射仪(XRD),傅里叶红外光谱仪(FTIR)和场发射透射电镜(FETEM)表征样品ZnS性质,电感耦合等离子发射体(ICP-OES)分析上清液性质,并研究该反应动力学过程。EDS和ICP分析表明,样品ZnS纯度达到85.45%,其上清液含有高浓度铁,含量为2 g/L,可用于制备复合亚铁絮凝剂,而其他重金属离子浓度均低于电镀废水排放标准。XRD分析表明,样品ZnS是立方晶型,调节pH和采用滴加方式能有效改善样品ZnS的晶型。采用Scherrer公式计算晶体粒径,结果表明,晶粒大小在3~6 nm之间。FTIR分析表明,样品ZnS呈现良好的红外透明性,且温度、pH和滴加方式对样品的红外透光性基本没有影响。FETEM结合XRD图表明,该纳米晶呈片状,近似为球形,呈多层叠加,分散性不明显,有团聚现象。动力学实验表明,逆一级动力学方程适合描述硫化沉淀的反应动力学过程,活化能为39.04 kJ/mol,沉淀过程受化学反应和扩散联合控制。 相似文献
963.
《Journal of environmental science and health. Part. B》2013,48(2):375-384
The uptake of an element by a plant is primarily dependent on the plant species, its inherent controls, and the soil quality. Amaranthus hybridus (green herbs) and Amaranthus dubius (red herbs) were chosen to investigate their response and ability to accumulate and tolerate varying levels of elements in their roots and shoots. Red herbs and green herbs were grown in soil pots contaminated with three mixtures of Cd(II), Ni(II), Pb(II), and Hg(II). Plants in the control treatment were grown in the absence of the heavy metals mixture. The distribution of Cd, Ni, Pb, and Hg in the plants (in roots, stems, and leaves) was determined in two stages. Stage 1, after 5 weeks of plant growth and stage 2, full grown after 10 weeks of growth. In the red herbs the Cd concentration in the leaves at stage 2 was 150 ppm and was present in higher concentrations than Ni, Hg, and Pb. At the highest contamination level, in the green herbs plant, Hg was present in the highest concentration in the root, i.e., 336 ppm at stage 1, while the level in the leaves was 7.12 ppm. Both the green and red herbs species showed an affinity for Ni and Cd with moderate to high levels detected in the leaves, respectively. 相似文献
964.
C. Dasch Houdeshel Christine A. Pomeroy Kevin R. Hultine 《Journal of the American Water Resources Association》2012,48(6):1178-1190
Abstract: Bioretention as sustainable urban stormwater management has gathered much recent attention, and implementation is expanding in mesic locations that receive more than 1,000 mm of annual precipitation. The arid southwestern United States is the fastest growing and most urbanized region in the country. Consequently, there is a need to establish design recommendations for bioretention to control stormwater from expanding urban development in this ecologically sensitive region. Therefore, we review the ecological limits and opportunities for designing bioretention in arid and semiarid regions. We incorporated USEPA Stormwater Management Model (SWMM) simulations to synthesize ecologically based design recommendations for bioretention in arid climates. From our review, an ideal bioretention garden area should be 6 to 8% of the contributing impervious drainage area (depending on region) with two layers of media, a 0.5‐m low‐nutrient topsoil layer above a 0.6‐m porous media layer that acts as temporary storage during a storm event. When planted with the suggested vegetation, this design maximizes stormwater treatment by promoting ecological treatment in the topsoil while promoting infiltration and evapotranspiration of stormwater by deep‐rooted shrubs that require no irrigation after establishment. This synthesis improves water resources management in arid and semiarid regions by introducing a sustainable bioretention design that protects local surface waters while reducing regional water demands for irrigation. 相似文献
965.
园林植物清除细菌能力的研究 总被引:32,自引:0,他引:32
为筛选出除菌能力较强的园林植物,应用撞击平皿法采用内膏蛋白胨琼脂培养基进行样品采集与培养,通过多元素方差分析方法确定测定值的可比条件,对园林植物清除空气中细菌的能力进行比较研究。结果表明,园林植物具有较强的清除细菌能力,其能力大小在不同种类间具一定差异;其中,一串红、接骨木、火炬树、京桃、树锦鸡儿等植物除菌率小于40%,落叶松、圆柏、垂榆、加杨、华北柽柳、鸡冠花、黑心菊等除菌率为40%~80%,油 相似文献
966.
Crisis management systems should be assessed and updated in petrochemical industries due to hazards, such as fire and explosion. Successful crisis management systems can protect both personnel and property in the petrochemical industries. The present study aimed to assess crisis management systems of five petrochemical plants in terms of three aspects, including organizational aspects, human aspects, and technical aspects. A questionnaire was designed, encompassing 34 items to cover all three aspects at both management and staff levels. A multi-criteria decision making (MCDM) approach, including the entropy method and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), was used to analyze the collected data. The outcomes of the entropy method indicated that organizational and human aspects had the greatest influence on crisis management systems of the plants with 58% and 49% importance at management and staff levels, respectively. The crisis management systems of the investigated plants were ranked and analyzed using the TOPSIS approach. The findings of this study could assist managers and other decision-makers to address the issues of crisis management systems in petrochemical industries. 相似文献
967.
Hassen Khazri Sihem Ben Hassine Ibtissem Ghorbel–Abid Rafik Kalfat Malika Trabelsi-Ayadi 《Environmental Forensics》2019,20(2):121-128
We investigated the occurrence of three pharmaceutical residues in four wastewater treatment plants (WWTPs) from northern Tunisia. The selected compounds were carbamazepine, naproxen, and ibuprofen; they are among the most commonly prescribed and widely used pharmaceutical agents worldwide. Samples (200?mL) were pre-concentrated using the solid phase extraction (SPE) enrichment procedure and the analysis of the pharmaceuticals was performed with high-performance liquid chromatography (HPLC-UV). The overall procedure provided limits of detection (LOD) lower than 0.5 µg.L?1and recoveries of 78–97%. For the carbamazepine compound, the mean concentrations were 60.58, 93.19, and 132 µg.L?1 for the Bizerte, Jendouba, and Tunis WWTPs, respectively. This pharmaceutical was not detected in the Beja WWTPs. Naproxen and ibuprofens were not detected in the Jendouba WWTP but were found in the three other WWTPs with concentrations ranging from 2.94 to 36.17 µg.L?1 and from 8.02 to 43.22 µg.L?1, respectively. From the obtained data, it seems that these WWTPs are not able to eliminate this kind of micro-pollutants. 相似文献
968.
Soudek P Petrová S Benesová D Kotyza J Vágner M Vanková R Vanek T 《Journal of environmental radioactivity》2010,101(6):446-450
A soil-plant transfer study was performed using soil from a former uranium ore processing factory in South Bohemia. We present the results from greenhouse experiments which include estimates of the time required for phytoremediation. The accumulation of 226Ra by different plant species from a mixture of garden soil and contaminated substrate was extremely variable, ranging from 0.03 to 2.20 Bq 226Ra/g DW. We found differences in accumulation of 226Ra between plants from the same genus and between cultivars of the same plant species. The results of 226Ra accumulation showed a linear relation between concentration of 226Ra in plants and concentration of 226Ra in soil mixtures. On the basis of these results we estimated the time required for phytoremediation, but this appears to be too long for practical purposes. 相似文献
969.
V.N. Jha R.M. Tripathi N.K. Sethy S.K. Sahoo A.K. Shukla V.D. Puranik 《Journal of environmental radioactivity》2010,101(9):717-722
A field study has been conducted to evaluate the 226Ra bioaccumulation among aquatic plants growing in the stream/river adjoining the uranium mining and ore-processing complex at Jaduguda, India. Two types of plant group have been investigated namely free floating algal species submerged into water and plants rooted in stream & riverbed. The highest 226Ra activity concentration (9850 Bq kg−1) was found in filamentous algae growing in the residual water of tailings pond. The concentration ratios of 226Ra in filamentous algae (activity concentration of 226Ra in plant Bq kg−1 fresh weight/activity concentration of 226Ra in water Bq l−1) widely varied i.e. from 1.1 × 103 to 8.6 × 104. Other aquatic plants were also showing wide variability in the 226Ra activity concentration. The ln-transformed filamentous algae 226Ra activity concentration was significantly correlated with that of ln-transformed water concentration (r = 0.89, p < 0.001). There was no correlation between the activity concentrations of 226Ra in stream/riverbed rooted plants and the substrate. For this group, correlation between 226Ra activity concentration and Mn, Fe, Cu concentration in plants were statistically significant. 相似文献
970.
固定化微生物-水生生物强化系统在前置库示范工程中的应用 总被引:3,自引:0,他引:3
在前置库中构建固定化微生物-水生生物强化系统处理太湖入湖河道污水,以减少入湖污染负荷.在驯化期加入复合微生物菌剂30 mg/kg,驯化期后每月投加1次(20 mg/kg),强化微生物的活性.监测期间(5-11月)库水进水ρ(TN)为0.54~1.59 mg/L,ρ(TP)为0.079~0.172 mg/L,ρ(CODMn)为5.41~13.40mg/L,前置库水力停留时间约为9 d,TN,TP和CODMn平均去除率分别为45.0%,42.2%和50.8%.固定化微生物区域微生物数量高于水生植物根际区1~2个数量级,反硝化菌数量达到109,水生植物根区微生物数量也高于示范区自然水体2~3个数量级以上.试验结果表明,固定化微生物-水生生物强化系统具有良好的环境适应能力,治理水体富营养化效果明显,但其在前置库中的长效运行,有待于进一步验证. 相似文献