无机碳对浮游藻类生长和群落结构的影响

采用水族箱生态模拟方法,利用碳酸钠和碳酸氢钠作为碱度调节剂设置不同碱度水平,研究了氮磷营养相对充足的试验水体中藻类各相关指标对无机碳的响应,并对试验过程中所测得的理化指标和生物指标进行统计分析.研究表明:富营养水体无机碳含量与藻类叶绿素水平存在着正相关关系;适当增加水体中的无机碳浓度能够改变蓝、绿藻门种类比例;当碱度水平达到一定程度时,铜绿微囊藻可以逐渐成为优势种,并从体系中上升,演替成为水华.     

Deliberative public participation and hexachlorobenzene stockpiles

This paper is concerned with the quality of citizen involvement in relation to the governance of industrial risks. Specifically, it explores the hexachlorobenzene (HCB) case relative to best practice public participation, which is consistent with deliberative democratic theory. The case could be judged a public participation failure given that the community committee in combination with the corporate sponsor was unable to agree on a mutually acceptable technological pathway. This stalemate might have been attributable in part to the time spent on the task of review. A diligent participation working party could have created a much more effective public participation plan, grounded in the core values of professional public participation practice.     

Effects of a herbicide-insecticide mixture in freshwater microcosms: risk assessment and ecological effect chain

Effects of chronic application of a mixture of the herbicide atrazine and the insecticide lindane were studied in indoor freshwater plankton-dominated microcosms. The macroinvertebrate community was seriously affected at all but the lowest treatment levels, the zooplankton community at the three highest treatment levels, with crustaceans, caddisflies and dipterans being the most sensitive groups. Increased abundance of the phytoplankton taxa Cyclotella sp. was found at the highest treatment level. Threshold levels for lindane, both at population and community level, corresponded well with those reported in the literature. Atrazine produced fewer effects than expected, probably due to decreased grazer stress on the algae as a result of the lindane application. The safety factors set by the Uniform Principles for individual compounds were also found to ensure protection against chronic exposure to a mixture of a herbicide and insecticide at community level, though not always at the population level.     

Changes in cell-type composition in digestive gland of slugs and its influence in biomarkers following transplantation between a relatively unpolluted and a chronically metal-polluted site

Changes in cell-type composition (CCTC) is a general phenomenon that takes place in the digestive gland epithelium of stressed molluscs. The aim of the present work was to determine whether CCTC is a reversible process in the digestive gland of sentinel slugs chronically exposed to metal pollution and how CCTC affects metal accumulation parameters and different cell and tissue biomarkers of exposure and effect. Slugs (Arion ater) from an abandoned zinc mine were transferred to a relatively unpolluted site and the other way around for 3, 10 and 28 d. The volume density of black silver deposits (Vv_BSD) after autometallography, and metallothionein (MT) levels were used as biomarkers of exposure to metals and CCTC and lysosomal responses were selected as effect biomarkers. Results indicated that slugs were sensitive to recent metal pollution; however, slugs chronically exposed to metals presented some characteristic features and were less responsive to pollution cessation without signs of CCTC reversal.     

Evaluation of the community multiscale air quality (CMAQ) model version 4.5: Sensitivities impacting model performance; Part II—particulate matter

This paper is Part II in a pair of papers that examines the results of the Community Multiscale Air Quality (CMAQ) model version 4.5 (v4.5) and discusses the potential explanations for the model performance characteristics seen. The focus of this paper is on fine particulate matter (PM_2.5) and its chemical composition. Improvements made to the dry deposition velocity and cloud treatment in CMAQ v4.5 addressing compensating errors in 36-km simulations improved particulate sulfate (SO₄²⁻) predictions. Large overpredictions of particulate nitrate (NO₃⁻) and ammonium (NH₄⁺) in the fall are likely due to a gross overestimation of seasonal ammonia (NH₃) emissions. Carbonaceous aerosol concentrations are substantially underpredicted during the late spring and summer months, most likely due, in part, to a lack of some secondary organic aerosol (SOA) formation pathways in the model. Comparisons of CMAQ PM_2.5 predictions with observed PM_2.5 mass show mixed seasonal performance. Spring and summer show the best overall performance, while performance in the winter and fall is relatively poor, with significant overpredictions of total PM_2.5 mass in those seasons. The model biases in PM_2.5 mass cannot be explained by summing the model biases for the major inorganic ions plus carbon. Errors in the prediction of other unspeciated PM_2.5 (PM_Other) are largely to blame for the errors in total PM_2.5 mass predictions, and efforts are underway to identify the cause of these errors.     

Elemental composition of particulate matters around Urmia Lake,Iran

Atmospheric particulate matters and their elements were concurrently measured at two sites located in the north and southeast parts of Urmia Lake from January to September 2013. At both sampling sites, average concentrations of total suspended particulate, particles with the aerodynamic diameter of smaller than 10 µm, smaller than 2.5 µm, and smaller than 1 µm were 260 ± 106, 180 ± 73, 30 ± 8, and 25 ± 7 µg m^?3, respectively. The analyzed water soluble ions accounted for approximately 11%–13% mass concentrations of total suspended particulate and 8%–9% of particles smaller than 10 µm, and the sum of the concentrations of the analyzed elements associated with both ranged from 9 to 41 µg m^?3 (6.5%–9.6% in mass) and 7 to 26 µg m^?3 (5.5%–11.3% in mass), respectively. Thus, particulate matter was composed of a complex mixture of minerals such as halite, quartz, gypsum, hexahydrite, and Bassanite.     

Characterisation of an extracellular polysaccharide produced by Bacillus mucilaginosus MY6-2 and its application in metal biosorption

A novel extracellular bioflocculant from Bacillus mucilaginosus MY6-2 was obtained by alcohol precipitation, dialysis and lyophilisation. The chemical analysis indicated that the bioflocculant was mainly composed of extracellular polysaccharide (named EPS MY6-2). Monosacchride composition result analysed by Gas chromatography indicated that EPS MY6-2 was mainly composed of Man, Glc, Gal, GlcA and GalA. The result of flocculating characteristics indicated that pH, EPS dosage and cation supplement had evident effect on flocculating activity of EPS MY6-2. The biosorption of iron ions from aqueous solution was tested with respect to pH, initial metal ion concentration and EPS dosage. The optimum biosorption conditions were as follows: pH 5.0, initial ion concentration from 200 to 800 mg/L and EPS dosage of 60 mg/L ion solution. The adsorption rates are maintained above 95% under these conditions. The adsorption data provided an excellent fit to both Langmuir and Freundlich isotherms, implying that the binding of the iron ions took place as a monolayer on the surface of the EPS.     

南充农村土壤中有机氯农药残留现状分析

本研究以四川省南充市某农村土壤为研究对象,于2010年和2011年连续两年对土壤中有机氯农药(HCH,DDT)残留情况进行了定点监测。研究结果表明,试区土壤HCHs在2011年基本未检出。两年的DDTs的检出率均为100%。OCPs主要残留物为p,p’-DDE,占残留总量75%以上。不同利用类型土壤中有机氯残留总量排序为:菜地>重点污染场地>基本农田>居民聚集区。所有土壤样品中的HCHs含量均达到国家《土壤环境质量标准》(GB15618-1995)一级标准(<0.05mg/kg),DDTs含量均达到二级标准(<0.50mg/kg)。残留污染较轻。     

中国八角莲属植物的研究进展

八角莲属小檗科八角莲属植物,为我国特有药用植物。近年来,随着经济社会的发展,已有不少研究集中在八角莲的分布与生物生态特征、化学成分、栽培研究、药用价值等方面。八角莲属植物的药效显著、用途很广,对其研究及野生资源采摘越来越多,导致该属植物分布及其数量急剧减少,因此对八角莲属植物的开发利用与保护亟待加强。     

PM2.5污染危害分析及防控措施研究

本文论述了PM2.5对环境的危害,在剖析PM2.5组成与来源的基础上,提出防控PM2.5的政策与技术方面的建议,以期为今后PM2.5的防控工作提供理论基础。