Influences of sediment dessication on phosphorus transformations in an intertidal marsh: formation and release of phosphine

This study investigated the effects of sediment dewatering on the phosphorus transformations concerning about the production and emission of phosphine in the intertidal marsh of the Yangtze Estuary. The concentrations of matrix-bound phosphine ranged from 18.62-72.53 ng kg⁻¹ and 31.14-61.22 ng kg⁻¹ within the August and January exposure incubations, respectively. The responses of matrix-bound phosphine concentrations to sediment dessication demonstrate that the production (or accumulation) of matrix-bound phosphine significantly increased with water loss at the start of the emersion incubations. However, further dehydration inhibited the formation of matrix-bound phosphine in sediments. The significant correlations of matrix-bound phosphine with the organic-P bacteria abundance and alkaline phosphatase activities implicate that the production of matrix-bound phosphine within the dessication incubations was linked closely to the microbial decomposition of organic P. The emissions of phosphine generally decreased with sediment dewatering, with the fluxes of 7.51-96.73 ng m⁻² h⁻¹ and 5.34-77.74 ng m⁻² h⁻¹ over the exposure incubations of both August and January, respectively. Also, it is observed that the releases of phosphine during the entire exposure periods were affected not only by its production but also by sediment water and redox conditions.     

盆栽植物净化甲苯废气

采用动态模拟法模拟盆栽植物对甲苯污染气体的净化,考察吊兰和金绿萝两种盆栽植物在净化甲苯过程中,甲苯入口浓度与植物对甲苯净化速率的关系。结果表明,2种盆栽植物对低浓度甲苯废气具有长期明显的净化效果。在相同条件下,吊兰茎叶和土壤的净化速率优于金绿萝体系。在植物的耐受浓度范围内,2种植物茎叶和土壤的净化速率均随着甲苯入口浓度的升高而增大,且白天的净化速率明显高于黑夜时的净化速率。在实验过程中,吊兰土壤体系的降解率随着甲苯浓度的升高逐渐下降;金绿萝土壤体系的降解率基本不受甲苯入口浓度的影响。吊兰盆栽体系的降解率明显大于金绿萝的降解率。两种植物盆栽体系的降解率随甲苯进口浓度的影响可以忽略。     

Organochlorine pesticides and polychlorinated biphenyls in soils surrounding the Tanggu Chemical Industrial District of Tianjin, China

The spatial distribution of persistent organic pollutants (POPs) was examined in soils surrounding the Tanggu Chemical Industrial District in Tianjin, China. The concentrations of hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs), hexachlorobenzenes (HCBs), and polychlorinated biphenyls (PCBs) were determined in 70 surface soils using accelerated solvent extraction and gas chromatography with electron capture detection. The results showed that the ranges of ∑HCH, ∑DDT, ΣHCB, and ∑PCB concentrations in soils were 2.1–12,549 μg?kg^?1 (average, 965 μg?kg^?1), n.d.–2,033 μg?kg^?1 (average, 88.4 μg?kg^?1), n.d.–1,924 μg?kg^?1 (average, 349 μg?kg^?1), and n.d.–373 μg?kg^?1 (average, 46.2 μg?kg^?1), respectively. Of these, HCHs were the dominant POPs, accounting for 75 % of the total organochlorine pesticide (OCP) residues. Overall, the spatial distribution of OCP concentrations showed a decreasing trend from the center of the Tanggu District to the surrounding areas. Two major pollution sources were Tianjin Dagu Chemical Co., Ltd. in the district center and the Tianjin Chemical Plant in Hangu District. In contrast, PCB concentrations were relatively high in the Haihe estuary to the east and low to the west of the study area. Component analysis of OCPs in these soils showed that they mainly came from industrial point sources. Compared with soils in other regions, soil DDT pollution was at a medium level in the Tanggu Chemical Industrial District, but associated HCH, HCB, and PCB pollution was relatively heavy. By multivariate statistical analyses, Tianjin Dagu Chemical Co., Ltd. was recognized as the main source of POPs, and soil properties were clarified to play an important role on the distribution and composition of POPs, especially the organic carbon content.     

焙烧条件对CuO/ZSM-5催化剂脱硫脱硝性能的影响

以ZSM-5分子筛为载体,通过浸渍法制备10％ CuO/ZSM-5(金属氧化物质量占载体质量)催化剂,以CH4为还原气,考察不同焙烧温度和焙烧时间对催化剂脱硫脱硝性能的影响.XRD和TPR的表征结果显示,最佳焙烧条件为550℃下焙烧4h,在此焙烧条件下,10％ CuO/ZSM-5催化剂达到的最高脱硝脱硫率分别为90.6％和98.8％.     

海水及浓海水吸收二氧化硫

采用鼓泡法研究了海水及浓海水对二氧化硫的吸收效果,并考察了吸收液温度、气体流量、盐度及碱度等因素的影响.结果表明,相同条件下,浓海水对二氧化硫的吸收能力较海水明显提高,且温度越高浓海水优势越明显,气体流量为200 mL/min,二氧化硫浓度为3 140 mg/m3,25℃时,浓海水的穿透时间较原海水延长20 min,60℃时则延长30 min.相同碱度条件下,盐度的增加对海水吸收二氧化硫无明显影响;而在相同盐度条件下,碱度的增加可显著提高海水吸收二氧化硫的能力.     

Comparing the Adoption of Contaminated Land Remediation Technologies in the United States,United Kingdom,and China

In many locations across the world, land contamination poses a serious threat to human health and the wider environment. For instance, a report published on April 17, 2014, revealed that China now has 16.1 percent of its land contaminated by various organic and inorganic contaminants, posing a range of challenges from human health risk to food security. The innovation and adoption of suitable remediation technologies is critical for solving land contamination issues. However, little is known about the pattern of remediation technology adoption, as well as its determining factors. This study uses a questionnaire survey in the United States, United Kingdom, and China to examine the spatial variation of remediation technology adoption. It further explores the temporal trend of remediation technology adoption using secondary data from the U.S. Superfund program. The study identified significant differences in remediation technology adoption among these countries, which are attributed to the different environmental, social, economic, and regulatory contexts. It is argued that the full implications of remediation technology adoption to sustainable development should be further studied, and policy instruments should be designed accordingly to promote those remediation technologies that align the best with long‐term sustainability. Technology developers may also use these implications to adjust their research and development priorities. © 2014 Wiley Periodicals, Inc.     

Annual input fluxes of heavy metals in agricultural soil of Hainan Island,China

The accumulation of heavy metals in farmland has become an important issue related to food security and environmental risk. The annual inputs of heavy metals (As, Cd, Hg, Pb, Cr, Cu, and Zn) to agricultural soil for a full year in Hainan Island have been studied. Three fluxes through the cultivated horizon were considered: (1) atmospheric depositions, (2) fertilization, and (3) irrigation water. The corresponding samples were collected and analyzed on a large regional scale. The total input fluxes show obvious spatial variability among different regions. The inventory of heavy metal inputs to agricultural land demonstrates that agricultural soil is potentially at risk of heavy metal accumulation from irrigation water. The potential at risk of heavy metal accumulation from atmospheric deposition and fertilizer is relatively low compared to irrigation. The results indicate that Hg is the element of prior concern for agricultural soil, followed by Cd and As, and other heavy metal elements represent little threat to the environment in the study area. This work provides baseline information to develop policies to control and reduce toxic elements accumulated in agricultural soil.     

Ni2＋对活性污泥活性及群落多样性的影响

通过检测活性污泥的电子传递体系活性以及生物多样性,研究Ni2＋对活性污泥微生物活性及群落多样性的影响。结果表明：与对照系统相比,5mg／L的Ni2＋对2,3,5-lriphenylteItrazoliumchloride（TTC．ETS）活性未产生显著的影响;但当Ni2＋的浓度进一步增大到10、20和40mg／L后,其对序批式反应器内活性污泥TTC—ETS活性的抑制率分别达到（36．794-11．14）％、（55．88±13．90）％和（70．97±6．78）％。低浓度Ni2＋．能增强活性污泥微生物对碳源的利用,但高于10mg／L的Ni2＋则显著抑制了活性污泥微生物对碳源的利用。各个SBR系统中微生物群落最常见的物种相近,物种丰富度和均一性则均有所不同,其中群落物种丰富度随着Ni2＋浓度的增加而逐渐减小。TTC—ETS活性、平均每孔颜色变化率、Shan—liOn指数和Simpson指数,与Ni2＋的胁迫浓度之间的显著相关性表明,它们均可有效地表征Ni2＋胁迫对活性污泥微生物活性及群落多样性的影响程度。     

Resilience: A New Consideration for Environmental Remediation in an Era of Climate Change

There has been a growing movement within the environmental industry to develop more sustainable approaches in environmental remediation. These have generally included carbon footprint analysis, life cycle assessment, and best management practices to reduce the overall net environmental, social, and economic impacts of investigation and remediation activities. One of the foundational reasons net environmental impacts are currently evaluated is to identify and, subsequently, reduce contributions to climate change, primarily greenhouse gas emissions. While this trend toward sustainability and reduction in impact to the global environment is both important and admirable, the approach to remediation design and long‐term planning now needs to evolve further to better incorporate climate resilience into sustainable remediation design and implementation: designing remediation solutions that account for the projected impacts of climate change, as well as have the capacity to adapt to changing conditions. As a global population, we are now beyond the point of being able to prevent climate change and instead need to plan for adapting to it. In remediation, the effects of climate change create both risks and opportunities which should be considered during remedial design and long‐term planning. Responsible parties may see the push for—and management of—these considerations through their internal corporate risk management. The authors of this paper propose a simple framework for climate adaptation and resilience evaluations and plan development for remediation projects. ©2015 Wiley Periodicals, Inc.