典型烧结厂周边土壤多氯联苯的环境污染特征

本文以唐山某典型烧结厂为研究对象,对铁矿石烧结厂排放的烟气及周边土壤样品进行采集,应用同位素稀释高分辨气相色谱-高分辨质谱联用法(HRGC/HRMS)测定了多氯联苯(PCBs)的含量,并研究了PCBs的同类物分布特征.其中烟气样品中类二英PCBs(dl-PCBs)总浓度为1.04—1.77ng·m~(-3),毒性当量值为8.99—19.32pg·WHO-TEQ·m~(-3).烧结厂周边土壤样品中dl-PCBs的总浓度为8.81—403.59pg·g~(-1),毒性当量值为0.05—0.65pg·WHO-TEQ·g~(-1),是背景土壤样品的(0.035pg·WHO-TEQ·g~(-1))的1—19倍.可以看出,该烧结厂周边环境土壤受到了企业所排放PCBs等有毒污染物的影响.大部分土壤样品的同类物分布特征相似;CB-118对土壤dl-PCBs浓度贡献率最大,贡献率为31.74%.CB-101对土壤指示性PCBs浓度贡献率最大,贡献率为52.82%.将土壤样品和烟气样品的同类物分布进行比较发现二者略有不同.尽管都是以低氯代同类物为主,但是烟气样品中最高的同类物是TrCBs,且随着氯代数的增加,浓度呈现明显下降的趋势;而土壤样品PeCBs浓度最高,PeCBs前后都呈现逐级下降的趋势.唐山市此烧结厂周边土壤无论是TEQ值,指示性PCBs总浓度,PCBs总浓度与其它研究相比都处于较高水平.     

南四湖沉积物中二噁英类化合物的分布

用1 3C同位素内标法 ,高分辨率气相色谱 高分辨率质谱对南四湖表层沉积物中 1 7种含 2 3 7 8 氯代二苯并二英 /呋喃 (PCDD/Fs)及 1 2种共平面多氯联苯 (Co PCBs)的含量、同系物异构体的分布特征、沉积通量、毒性当量及来源进行了初步分析 ,并与山东近海 (日照、烟台、青岛 )的测定结果进行比较 .总Co PCBs含量分别为 5 4 4pg·g- 1 dw (南阳湖 )和 41 4pg·g- 1 dw (微山湖 ) .总PCDD/Fs含量分别为 1 0 6 7pg·g- 1 dw (南阳湖 )和1 47 0pg·g- 1 dw (微山湖 ) .两湖含 2 3 7 8 PCDD/Fs异构体对总毒性当量浓度的贡献基本相同 ,即以四—五氯代异构体为主 .PCDD/Fs含量次序为青岛 >日照 >南四湖 >烟台 .南四湖、日照、烟台近海沉积物中的PCDD/Fs对总TEQ (PCDD/F TEQ PCB TEQ)的贡献为68 8%— 93 0 % .南四湖与山东近海沉积物中PCDDs/PCDFs比值和OCDD %∑百分比表明 ,山东省PCDD/Fs的来源较为一致 ,相对恒定 .除河口处外 ,大气沉降应是南四湖及山东近海PCDD/Fs的主要来源 .     

香港海域翡翠贻贝(Perna viridis L.)中多氯联苯的研究

用气相色谱 毛细管双柱 电子捕获检测器研究了香港海域翡翠贻贝中多氯联苯(PCBs)的含量及其分布特征 ,结果表明 ,翡翠贻贝体内PCBs的污染现状与香港周边污染状况相符 ,在香港某些海域中翡翠贻贝体内PCBs有较高的含量 ,特别是靠近香港陆地的海域 ,PCBs总浓度最高达 3 0 3ng·g- 1 (干样 ) .PCBs同系物的分布亦有明显的不同特征 .运用二恶英毒性当量 (TEQ)表征翡翠贻贝中PCBs的毒性 ,TEQ最高值达 4 96ng·kg- 1 ,低于美国FDA允许值     

南四湖沉积物中二(口恶)英类化合物的分布

用13C同位素内标法,高分辨率气相色谱-高分辨率质谱对南四湖表层沉积物中17种含2,3,7,8-氯代二苯并二NB12E英/呋喃(PCDD/Fs)及12种共平面多氯联苯(Co-PCBs)的含量、同系物异构体的分布特征、沉积通量、毒性当量及来源进行了初步分析,并与山东近海(日照、烟台、青岛)的测定结果进行比较.总Co-PCBs含量分别为54.4pg·g-1dw(南阳湖)和41.4pg·g-1dw(微山湖).总PCDD/Fs含量分别为106.7pg·g-1 dw(南阳湖)和147.0pg·g-1 dw(微山湖).两湖含2,3,7,8-PCDD/Fs异构体对总毒性当量浓度的贡献基本相同,即以四-五氯代异构体为主.PCDD/Fs含量次序为青岛＞日照＞南四湖＞烟台.南四湖、日照、烟台近海沉积物中的PCDD/Fs对总TEQ(PCDD/F-TEQ+PCB-TEQ)的贡献为68.8%-93.0%.南四湖与山东近海沉积物中PCDDs/PCDFs比值和OCDD%∑百分比表明,山东省PCDD/Fs的来源较为一致,相对恒定.除河口处外,大气沉降应是南四湖及山东近海PCDD/Fs的主要来源.     

烧结厂烟尘和静电除尘器灰尘中二噁英的分布特征

研究了烧结厂烟道烟尘和静电除尘器灰尘中二噁英的浓度和分布特征.结果显示,烧结台车机头烟道烟尘和机尾烟道烟尘中二噁英的总含量分别为867.49±215.41和170.35±51.12 pg·Nm-3,毒性当量分别36.53±4.47和9.13±2.40pg WHO-TEQ·Nm-3;机头静电除尘器灰尘和机尾静电除尘器灰尘的总含量分别为2423.59±100.01和157.29±36.83 pg·g-1 dw,毒性当量分别71.67±0.62和7.50±1.08 pg WHO-TEQ·g-1 dw.烧结中二噁英的分布以PCDFs为主,而且PCDFs各同系物的浓度与Cl原子取代数目呈负相关(r2=0.98).在WHO-TEQs中2,3,4,7,8-PeCDF的贡献最大,占总TEQ值的45%左右.     

高分辨率气相色谱/高分辨率质谱同位素内标法测定烟气样品中的多氯萘

多氯萘(PCNs)同二噁英(PCDD/Fs)和类二噁英多氯联苯(PCBs)类似,在烟气中的含量处于痕量水平,一般都在pg·m-3以下,因此分析方法要求有较高的灵敏度和选择性.以国内外的研究方法和参考文献为基础,建立了同位素内标稀释高分辨气相色谱/高分辨率质谱联用对垃圾焚烧发电厂的烟气样品中的PCNs进行分析.结果表明,该方法对17种氯取代位的PCNs单体的空白干扰在N.D.—2.1 pg之间;方法检出限范围为2.8—9.1 pg·nm-3,线性范围为0.40—240 pg·μL-1;空白加标实验中目标化合物的回收率为84.62%—116.21%,提取内标回收率为40.41%—75.79%,采样内标的回收率为88.92%—89.89%.实际烟气样品测得17种PCNs的同系物浓度分布在8.79—509 pg·nm-3之间,PCN-6的含量最高,PCNs-31S含量最低,相对标准偏差在4.43%—14.44%.该分析方法具有较高的准确性和可靠性,适用于烟气样品中多氯萘物质的测定.     

典型灌区稻田多氯联苯残留特征及生态风险评估

以南方典型小灌区的两块稻田为试验小区,采用GC-ECD对其田间水体和土壤中EPA优控14种多氯联苯（PCBs）进行了检测和定量分析。结果表明,14种PCBs同系物有不同程度检出,优势残留物主要以3氯和5氯取代PCBs为主,水和土壤占PCBs总量的88.24%、90.13%。水中∑PCBs质量浓度为24.09～310.34ng·L^-1,其中地表水均值为245.84ng·L^-1,地下水均值为96.46ng·L^-1;土壤中∑PCBs质量分数为10.01～54.63ng·g^-1,均值为33.92ng·g^-1。稻田地表水中的PCBs质量浓度远高于地下水,垂向迁移明显但速度较慢;稻田地表及地下水中PCBs质量浓度有随时间衰减的趋势,可能与水稻的生育周期有关;淹灌处理稻田PCBs质量分数高于节水灌溉。研究区毒性当量TEQ在2.65×10^-2～7.54×10^-2pg·g^-1之间,生态风险处于中等水平。地表及地下水均遭到污染,再加上PCBs具有生态累积效应,危害不容忽视。     

不同水源灌溉的农田表层土壤中多氯联苯和多溴联苯醚的浓度分布特征

本工作主要关注北京郊区污水河、地下水及混合水源灌溉的3块农田的表层土壤中,26种多氯联苯(PCBs)和14种多溴联苯醚(PBDEs)的浓度分布特征,并对目标污染物各单体浓度之间的相关性进行了统计学分析.结果显示,所有供试表层土壤样品中共检出26种PCBs(∑26PCBs),浓度水平范围为130—1.93×103ng.kg-1干重.检出的PCBs种类包括12种共平面多氯联苯异构体(15.6—433 ng.kg-1干重),6种指示型多氯联苯异构体(50.7—452 ng.kg-1干重)和其它8种多氯联苯同系物(52.1—1.15×103ng.kg-1干重).同时还检出14种多溴联苯醚同系物(∑14PBDEs),浓度水平范围为1.81—14.4μg.kg-1干重,其中十溴联苯醚(BDE-209)为最主要的组分,约占总组分94%以上.污水河河水和地下水混合灌溉的农田中PCBs和PBDEs的浓度大于地下水灌溉农田中的含量.此外,在所有样品中发现高氯代的多氯联苯同系物(氯原子数≥4)浓度之间存在显著的相关性,可能与灌溉水源和土壤对高氯代联苯的强保留等因素有关.     

苏南城市群河流表层沉积物中二噁英和共平面多氯联苯的浓度水平、来源和生态风险

对25个苏南城市群河流表层沉积物中二噁英及17个样品中共平面多氯联苯的监测表明,PCDD/Fs和dl-PCBs中位值分别为6.61 ng WHO1998TEQ·kg-1和1.43 ng WHO1998TEQ·kg-1,均处于我国和亚洲河流表层沉积物的中等水平.PCDD/Fs和dl-PCBs含量水平与经济发展水平和工业规模呈现正相关.开发区新建企业是PCDD/Fs的新排放源之一.统计分析表明,南通PCDD/Fs的排放以燃煤和农药五氯酚的使用为主,无锡来源于农业活动和少量工业污染源,苏州则受到目前工业排放源的影响,3个城市的PCBs主要来源于历史上PCBs工业品的使用.96%的采样点总毒性当量浓度(TEQ)超过加拿大沉积物质量指导值(ISQGs),88%的采样点超过美国EPA ISQGs,表明苏南城市群表层沉积物PCDD/Fs和dl-PCBs具有一定生态风险.     

生活垃圾焚烧厂烟气中二■英的分布及净化特征

以广州市某大型生活垃圾焚烧发电厂的3台焚烧炉(750 t·d~(-1))为对象,研究了焚烧烟气净化前后二■英类同系物的分布特征及其污染控制效果.结果表明,采用"半干法脱酸+活性炭+布袋除尘"烟气净化工艺对二■英的去除率能达到97.3%—99.4%.焚烧烟气中二■英类同系物的分布特征表明,生活垃圾焚烧发电过程中二■英主要在烟气换热过程合成.烟气净化过程中,活性炭喷射+布袋除尘净化系统对二■英类同系物的去除效率存在一个优先级关系,即PCDDs〉PCDFs且高氯代PCDFs〉低氯代PCDFs.净化后的烟气中二■英类同系物2,3,4,7,8-PeCDF的质量浓度与对应的二■英当量浓度的相关性最高,相关系数R~2为0.959,可以考虑将2,3,4,7,8-PeCDF作为二■英的快速应急检测的指示物.     

Applications of chitosan in food,pharmaceuticals, medicine,cosmetics, agriculture,textiles, pulp and paper,biotechnology, and environmental chemistry

Environmental Chemistry Letters - Chitosan is a biopolymer obtained from chitin, one of the most abundant and renewable materials on Earth. Chitin is a primary component of cell walls in fungi, the...     

Fragmentation of Phragmites Habitats, Minimum Viable Population Size, Habitat Suitability, and Local Extinction of Moths, Midges, Flies, Aphids, and Birds

Results from populations of insects and birds inhabiting Phragmites habitats were used to analyze effects of fragmentation. Flush-crash cycles of the stem-boring moth Archanara geminipuncta (Lepidoptera, Noctuidae) showed regionally concurrent, local extinctions despite an originally enormous population size (more than 180,000 adults), emphasizing the importance of metapopulation dynamics. Further, A. geminipuncta could be considered a keystone species, since shoot damage facilitated more than twenty species of herbivores, saprovores (of the caterpillars' feces), and their parasitoids. The gall midge Lasioptera arundinis could survive only in side shoots induced by shoot damage of A. geminipuncta .
Small Phragmites stands had thinner shoots (due to a water or nutrient deficiency) and shoots with more leaves (due to a better light supply) than large stands, thereby influencing species-specific demands for habitat suitability and nutritiousness of reed tissue. In other words significance of habitat fragmentation could not be assessed by area alone. For example, two chloropid flies depending on thin, yellowish shoots survived only in small habitats or in the unmown edges of large habitats.
Local persistence of Phragmites herbivores depended on much larger population sizes than could be expected from a population size sufficient to maintain genetic variation. At least 11,000 adults of the gall midge Giraudiella inclusa (or more than 84,000 galls) were necessary to avoid local extinction.
With regard to conservation management of reed habitats, nature reserves should consist of old and unmown reeds, have fewer disturbed (particularly, fewer mown) habitat edges, measure more than two hectares (priority should go to the largest remaining fragments), and be surrounded by nearby reed habitats providing reservoir populations and diverse shoot types.     

The distribution of,and relation among,mercury and methylmercury,organic carbon,carbonate, nitrogen and phosphorus,in periphyton of the South Florida ecosystem

Periphyton samples from Water Conservation Areas, Big Cypress National Preserve, and Everglades National Park in south Florida were analyzed for concentrations of total mercury, methylmercury, nitrogen, phosphorus, organic carbon, and inorganic carbon. Concentrations of total mercury in periphyton decrease slightly along a gradient from north‐to‐south. Both total mercury and methylmercury are positively correlated with organic carbon, nitrogen and phosphorus in periphyton. In horizontal sections of periphyton mats, total mercury concentrations tend to be largest at the tops and bottoms of the mats. Methylmercury concentrations tend to be the largest near the bottom of mats. These localized elevated concentrations of methylmercury suggest that there are “hot spots”; of methylmercury in periphyton.     

Lead,cadmium, copper,zinc, iron,and calcium in human hair as a function of gender,age, smoking,and hair dyeing

Hair samples were collected randomly from 110 subjects (55 male and 55 female) ranging in age from (<15–60) years. Each subject was asked to complete a personal questionnaire describing his/her sex, age, general health, smoking, use of hair dyes, occupational area, and living habits. Concentrations of Pb, Cd, Cu, Zn, Fe, and Ca in human hair samples were evaluated using atomic absorption spectrometry. Results indicated that concentrations of Pb, Cd, Cu, and Zn in the hair of smokers were higher than those in the hair of non-smokers, whereas, Fe and Ca concentrations in hair of smokers were lower than those in hair of non-smokers. Moreover, the concentrations of these elements are higher in dyed hair compared with undyed hair.     

Research progress on distribution,sources, identification,toxicity, and biodegradation of microplastics in the ocean,freshwater, and soil environment

• Microplastics are widely found in both aquatic and terrestrial environments. • Cleaning products and discarded plastic waste are primary sources of microplastics. • Microplastics have apparent toxic effects on the growth of fish and soil plants. • Multiple strains of biodegradable microplastics have been isolated. Microplastics (MPs) are distributed in the oceans, freshwater, and soil environment and have become major pollutants. MPs are generally referred to as plastic particles less than 5 mm in diameter. They consist of primary microplastics synthesized in microscopic size manufactured production and secondary microplastics generated by physical and environmental degradation. Plastic particles are long-lived pollutants that are highly resistant to environmental degradation. In this review, the distribution and possible sources of MPs in aquatic and terrestrial environments are described. Moreover, the adverse effects of MPs on natural creatures due to ingestion have been discussed. We also have summarized identification methods based on MPs particle size and chemical bond. To control the pollution of MPs, the biodegradation of MPs under the action of different microbes has also been reviewed in this work. This review will contribute to a better understanding of MPs pollution in the environment, as well as their identification, toxicity, and biodegradation in the ocean, freshwater, and soil, and the assessment and control of microplastics exposure.     

Trends and causes of severity, size, and number of fires in northwestern California, USA

Research in the last several years has indicated that fire size and frequency are on the rise in western U.S. forests. Although fire size and frequency are important, they do not necessarily scale with ecosystem effects of fire, as different ecosystems have different ecological and evolutionary relationships with fire. Our study assessed trends and patterns in fire size and frequency from 1910 to 2008 (all fires > 40 ha), and the percentage of high-severity in fires from 1987 to 2008 (all fires > 400 ha) on the four national forests of northwestern California. During 1910-2008, mean and maximum fire size and total annual area burned increased, but we found no temporal trend in the percentage of high-severity fire during 1987-2008. The time series of severity data was strongly influenced by four years with region-wide lightning events that burned huge areas at primarily low-moderate severity. Regional fire rotation reached a high of 974 years in 1984 and fell to 95 years by 2008. The percentage of high-severity fire in conifer-dominated forests was generally higher in areas dominated by smaller-diameter trees than in areas with larger-diameter trees. For Douglas-fir forests, the percentage of high-severity fire did not differ significantly between areas that re-burned and areas that only burned once (10% vs. 9%) when re-burned within 30 years. Percentage of high-severity fire decreased to 5% when intervals between first and second fires were > 30 years. In contrast, in both mixed-conifer and fir/high-elevation conifer forests, the percentage of high-severity fire was less when re-burned within 30 years compared to first-time burned (12% vs. 16% for mixed conifer; 11% vs. 19% for fir/high-elevation conifer). Additionally, the percentage of high-severity fire did not differ whether the re-burn interval was less than or greater than 30 years. Years with larger fires and greatest area burned were produced by region-wide lightning events, and characterized by less winter and spring precipitation than years dominated by smaller human-ignited fires. Overall percentage of high-severity fire was generally less in years characterized by these region-wide lightning events. Our results suggest that, under certain conditions, wildfires could be more extensively used to achieve ecological and management objectives in northwestern California.     

Design,synthesis, antinociceptive,and anti-inflammatory properties of thiazolopyrimidine derivatives

Ten 2-(substituted benzylidene)-7-(4-chlorophenyl)-5-(furan-2-yl)-2H-thiazolo[3,2-a]pyrimidin-3(7H)-one derivatives were synthesized and evaluated. A series of heterocyclic, 2-(substituted benzylidene)-7-(4-chlorophenyl)-5-(furan-2-yl)-2H-thiazolo[3,2-a]pyrimidin-3(7H)-one were synthesized by reaction of 7-(4-chloro phenyl)-5-(furan-2-yl)-2H-thiazolo[3,2-a]pyrimidin-3(7H)-one with appropriately substituted aldehydes in the presence of anhydrous sodium acetate and glacial acetic acid. The antinociceptive activity was evaluated by tail-flick technique, anti-inflammatory activity was evaluated by carrageenan-induced paw edema test and their ulcerogenicity index was determined. The para-substituted methyl, hydroxy, fluoro, chloro, bromo, and nitro derivatives showed significant antinociceptive and anti-inflammatory activities. The detailed synthesis, spectroscopic data, and pharmacological screening of the synthesized compounds were reported.     

Topographically generated fronts,very nearshore oceanography,and the distribution of chlorophyll,detritus, and selected diatom and dinoflagellate taxa

At four sites (Sunset Bay, Miller's Cove, and Shore Acres 43° 20.13 N; 124° 22.40 W, Nellies Cove 42° 44.75 N; 124° 29.75 W) along the Oregon coast, USA, relationships between fronts associated with shore-parallel foam lines and the distributions of chlorophyll, selected phytoplankters, and detritus were investigated. Sampling dates at the study sites were as follows: Sunset Bay, 1 August 1997, 25 June 1999 and 20 July 1999; Miller's Cove, 24 August 2000; Shore Acres, 19 July 1999 and 16 August 2000; Nellies Cove 17 August 2000 and 31 August 2000. Conductivity, temperature and depth data were used to describe the water masses on either side of the fronts, and vertical plankton tows with a 53-m mesh net were used to describe the distribution of selected phytoplankters and detritus. At the cove sites during upwelling, fronts marked the presence of warm water within the bay and cooler water offshore. Chlorophyll a (Chl a) and phytoplankton concentrations were generally lower within the coves than seaward while detritus concentrations were higher. From 3 July 2000 to 15 September 2000, a period when upwelling winds from the north prevail, a time series of samples was collected at Sunset Bay. The front was only present during periods of upwelling favorable winds. During these periods there were significantly higher concentrations of Chl a, Pseudo-nitzschia spp., and Protoperidinium spp. seaward of the front than landward. During downwelling winds the front was absent and there were no significant differences in the concentrations inside and outside the mouth of the bay. At Shore Acres, an exposed, relatively straight stretch of shoreline, the shore-parallel front appears to be formed by boundary mixing. Chl a and phytoplankton from the coastal ocean spread well shoreward of the boundary-mixing front. When present, the front at the mouth of the coves and bay indicated the presence of water masses with distinct physical and biological characteristics, but not at Shore Acres. Alongshore differences in the very nearshore oceanography, by altering the availability of continental shelf phytoplankton production, may affect both the growth rates of intertidal benthic suspension feeders and community structure.Electronic Supplementary Material Supplementary material is available in the online version of this article at .Communicated by J.P. Grassle, New Brunswick