Characterization of polychlorinated dibenzo-p-dioxins and dibenzofurans in different particle size fractions of marine sediments

The distribution of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) was examined according to particle size in marine sediments, with a particular focus on fine particulates. Samples from different coastal sites were fractionated into five size groups (<2, 2-5, 5-10, 10-20, and 20-63 microm diameter) by gravitational split-flow thin fractionation. Despite the different size profiles and PCDD/F contents of the sediments at each site, PCDD/F levels in fractionations tended to increase as the particle size decreased; the PCDD/F levels in the finest particles were up to 16 times higher than in the coarsest particles, which was associated with their organic carbon contents. Log normalization showed high levels of PCDD/Fs in the fine silt particles (2-10 microm), which are consumable by aquatic biota. Because of the different toxicity and bioavailability of PCDD/Fs in different sediment particle sizes, it is important to study particle actions to understand their effects on the aquatic ecosystem.     

Forms and distribution of selenium at different depths and among particle size fractions of three Taiwan soils

The bioavailability of selenium in soils for plants depends more on its forms than on its total concentration. The purpose of the present study was to examine the solid-phase forms of selenium at different depths of three soil series representing major farming soil groups in Taiwan as well as the amounts of selenium in sand, silt and clay fractions of the soils. The study was conducted by means of sequential extraction to obtain the amounts of selenium and the distribution of various solid-phase forms of selenium at different depths of Pinchen (121 degrees 11(')E, 24 degrees 55(')N), Toulun-Sheto (120 degrees 55(')E, 24 degrees 50(')N), and Chunliao (120 degrees 25(')E, 23 degrees 57(')N) soil series. The amounts of metal oxide-bound form of selenium in the three soil series were the largest, with those of Pinchen and Toulun-Sheto soil series exceeding 50% of the total amounts of selenium and that of Chunliao soil series maintained at 30-40%. In the Pinchen and Toulun-Sheto soil series, the amounts of selenium in clay fractions were the largest, with a significant difference between the clays with and without metal oxides and organic matter removed. The amounts of selenium remained high in silt and/or sand fractions of the Chunliao soil series with metal oxides and organic matter removed. Metal oxide and organic matter contents of the three soil series mainly affect the amounts of various solid-phase forms of selenium and their distribution in different depths and particle size fractions of the soils. This observation of selenium associated with soil constituents was in good agreement with the results of the adsorption of selenite and selenate by the three soil series.     

The influences of ambient particle composition and size on particle infiltration in Los Angeles, CA, residences

Particle infiltration is a key determinant of the indoor concentrations of ambient particles. Few studies have examined the influence of particle composition on infiltration, particularly in areas with high concentrations of volatile particles, such as ammonium nitrate (NH4NO3). A comprehensive indoor monitoring study was conducted in 17 Los Angeles-area homes. As part of this study, indoor/outdoor concentration ratios during overnight (nonindoor source) periods were used to estimate the fraction of ambient particles remaining airborne indoors, or the particle infiltration factor (FINF), for fine particles (PM2.5), its nonvolatile (i.e., black carbon [BC]) and volatile (i.e., nitrate [NO3-]) components, and particle sizes ranging between 0.02 and 10 microm. FINF was highest for BC (median = 0.84) and lowest for NO3- (median = 0.18). The low FINF for NO3- was likely because of volatilization of NO3- particles once indoors, in addition to depositional losses upon building entry. The FINF for PM2.5 (median = 0.48) fell between those for BC and NO3-, reflecting the contributions of both particle components to PM25. FINF varied with particle size, air-exchange rate, and outdoor NO3- concentrations. The FINF for particles between 0.7 and 2 microm in size was considerably lower during periods of high as compared with low outdoor NO3- concentrations, suggesting that outdoor NO3- particles were of this size. This study demonstrates that infiltration of PM2.5 varies by particle component and is lowest for volatile species, such as NH4NO3. Our results suggest that volatile particle components may influence the ability for outdoor PM concentrations to represent indoor and, thus, personal exposures to particles of ambient origin, because volatilization of these particles causes the composition of PM2.5 to differ indoors and outdoors. Consequently, particle composition likely influences observed epidemiologic relationships based on outdoor PM concentrations, especially in areas with high concentrations of NH4NO3 and other volatile particles.     

Chemical composition of aerosol size fractions at a coastal site in southwestern Italy: seasonal variability and transport influence

The present study focuses on the elemental characterization of fine and coarse particles collected at a coastal site of southwestern Italy, in a suburban area of the Calabria region. A chemical tracer analysis was carried out to identify the major emission sources influencing on the atmospheric aerosol levels. Size-resolved particulate samples were collected during three 2-week seasonal sampling campaigns: autumn (19 October to 2 November 2003), winter (19 January to 2 February 2004) and spring (26 April to 10 May 2004). Ambient concentrations of selected elements (Fe, Mn, Mg, Ca, V, Cu, Cr, Ni, Zn, Pb, and Cd) associated to fine and coarse size fractions were determined using atomic absorption spectrometry (AAS). The enrichment factor method was applied, suggesting a prevailing anthropogenic component for all the detected elements, with Fe, Mg, Mn, and Ca as exceptions. Trajectory sector analysis was used in order to discriminate the influence of different air mass origins and paths. Long-range transport from both the continental Europe and the Saharan region proved to be the main influencing factors. African dust outbreaks, whose occurrence frequency was greater during the autumn and spring seasonal monitoring periods, gave rise to a total of eight exceedances of the European Commission (EC) PM10 daily limit value as well as an increase in values of the crustal-derived elements (Fe, Mg, and Ca). Long-range transport from the heavily industrialized area of Central/Eastern Europe contributed to the high levels of Zn, Cd, and Pb that were recorded during the winter sampling campaign. Seasonal trend and comparison with measurements previously performed across the Mediterranean basin were also presented and discussed.     

Biological activity in metal-contaminated calcareous agricultural soils: the role of the organic matter composition and the particle size distribution

Organic matter (OM) plays a key role in microbial response to soil metal contamination, yet little is known about how the composition of the OM affects this response in Mediterranean calcareous agricultural soils. A set of Mediterranean soils, with different contents and compositions of OM and carbonate and fine mineral fractions, was spiked with a mixture of Cd, Cu, Pb, and Zn and incubated for 12 months for aging. Microbial (Biolog Ecoplates) and enzyme activities (dehydrogenase, DHA; β-galactosidase, BGAL; phosphatase, PHOS; and urease, URE) were assessed and related to metal availability and soil physicochemical parameters. All enzyme activities decreased significantly with metal contamination: 36–68 % (DHA), 24–85 % (BGAL), 22–72 % (PHOS), and 14–84 % (URE) inhibitions. Similarly, catabolic activity was negatively affected, especially phenol catabolism (～86 % compared to 25–55 % inhibition for the rest of the substrates). Catabolic and DHA activities were negatively correlated with ethylenediaminetetraacetic acid (EDTA)-extractable Cd and Pb, but positively with CaCl₂, NaNO₃, and DTPA-extractable Cu and Zn. Soluble OM (water- and hot-water-soluble organic C) was positively related to enzyme and catabolic activities. Recalcitrant OM and fine mineral fractions were positively related to BGAL and PHOS. Conversely, catabolic activity was negatively related to clay and positively to silt and labile OM. Results indicate that the microbial response to metal contamination is highly affected by texture and OM composition.     

Occurrence of estrogenic effects in sewage and industrial wastewaters in Beijing, China

Estrogenic potencies of the effluents or water samples from wastewater treatment plants (WWTPs), industries and hospitals and some receiving rivers in Beijing city were estimated by using a human estrogen receptor recombinant yeast assay. Estrogenic activity of industrial wastewaters was found to range from 0.1 to 13.3 ng EEQ/L and decreased to the range of 0.03-1.6 ng EEQ/L after treatment. Estrogenic activity in WWTP influent ranged from 0.3 to 1.7 ng EEQ/L and decreased to the range of 0.05-0.5 ng EEQ/L after treatment. In the receiving river waters, the estrogenic effect range was 0.1-4.7 ng EEQ/L. These data suggest that treated industrial effluents and WWTP effluents of concern are not the only source of estrogenic pollution in surface waters in Beijing city. EEQ levels in Beijing river water are likely attributable to untreated municipal and industrial wastewaters discharged directly into the river.     

Ultraviolet disinfection of fecal coliform in municipal wastewater: effects of particle size.

Suspended solids interfere with the efficiency of disinfection using UV radiation by decreasing the rate of disinfection and inducing tailing. However, conventional measures of solids (total suspended solids, turbidity, and UV transmittance) do not adequately predict the presence or degree of these effects. Bacteria and viruses can become associated with particles in wastewater. A fractionation technique was developed to separate particle-associated bacteria into three fractions, based on particle size. The results show that the degree to which particles interfere with UV disinfection efficiency is dependent on particle size. The small size fraction (< 5 microm) consistently produced a statistically significant faster disinfection rate than the large fraction (> 20 microm), with the unfiltered sample and the medium fraction (particles > 5 microm, but < 20 microm) between the two extremes. Tailing also was observed only in the large fraction. Correlations between the disinfection rate constant and the percentage of large fraction bacteria of a sample were good.     

Distribution, availability, and sources of trace metals in different particle size fractions of urban soils in Hong Kong: Implications for assessing the risk to human health

The concentration and loading distribution of trace metals (Cu, Zn, Pb, Co, Ni, Cr, and Mn) and major elements (Al, Ca, Fe, and Mg) in different particle size fractions (2000-280, 280-100, 100-50, 50-10, 10-2, and <2 μm) of surface soils from highly urbanized areas in Hong Kong were studied. The enrichment of Pb, Cu, and Zn in the urban soils was strongly influenced by anthropogenic activities, and Pb accumulated in fine particles was mainly derived from past vehicular emissions as shown by Pb isotopic signatures. Trace metals primarily accumulated in clay, fine silt, and very fine sand fractions, and might pose potential health risks via the inhalation of resuspended soil particles in the air (PM₁₀ or PM_2.5), and ingestion of adhered soils through the hand-to-mouth pathway. The mobility, bioavailability, and human bioaccessibility of Pb and Zn in bulk soils correlated significantly with metal concentrations in fine silt and/or very fine sand fractions.     

Distribution of polybrominated diphenyl ethers and dust particle size fractions adherent to skin in indoor dust,Pretoria, South Africa

In order to determine human exposure to the indoor toxicant, selection of dust fraction and understanding dust particle size distribution in settled indoor dust are very important. This study examined the influence of dust particle size on the concentration of polybrominated diphenyl ethers (PBDEs) congeners, assessed the distribution of dust particle size and characterized the main indoor emission sources of PBDEs. Accordingly, the concentrations of PBDE congeners determined in different indoor dust fractions were found to be relatively higher in the order of dust particle size: 45–106 μm?>?(<45 μm)?>?106–150 μm. The finding shows arbitrary selection of dust fractions for exposure determination may result in wrong conclusions. Statistically significant moderate correlation between the concentration of Σ₉PBDEs and organic matter content calculated with respect to the total dust mass was also observed (r?=?0.55, p?=?0.001). On average, of total dust particle size <250 μm, 93.4 % (m/m%) of dust fractions was associated with less than 150 μm. Furthermore, of skin adherent dust fractions considered (<150 μm), 86 % (v/v%) is in the range of particle size 9.25–104.7 μm. Electronic materials treated with PBDEs were found the main emission sources of PBDE congeners in indoor environment. Based on concentrations of PBDEs determined and mass of indoor dust observed, 150 μm metallic sieve is adequate for human exposure risk assessment. However, research in this area is very limited and more research is required to generalize the fact.     

生物吸附-膜反应器富集生活污水中碳源物质的特性

设计并构建了生物吸附-微滤膜反应器,利用活性污泥的吸附作用及微滤膜的高效分离作用,处理来自不同生活污水处理厂的进水,分析典型城市污水中碳源物质的形态分布,以及生物吸附-微滤膜反应器对生活污水中含碳物质的富集分离效果。结果表明,生物吸附-微滤膜反应器对胶体COD的去除率较高,为60%~76%,对溶解态COD的去除率较低,为29%~38%;不同HRT对反应器的运行效果影响不大,综合考虑COD富集率及系统运行的经济性,本研究推荐的运行参数为SRT=2 d,HRT=22 min,藉此,生物吸附-膜反应器对碳源物质的富集回收率可达到50.0%左右。     

Content and distribution of forms of organic N in soil and particle size fractions after long-term fertilization

Most of the N in surface soils occurs in organic forms, and when mineralized it plays a key role in soil fertility and plant nutrition. Our objective was to study the effect of long-term applications of organic manure on the content and distribution of forms of organic N in bulk soil and soil particle size fractions to characterize the inherent soil nitrogen fertility. Five treatments were as follows: (1) CK (no fertilizer and no manure added), (2) mineral fertilizer only, (3) straw + NPK, (4) green manure + NPK and (5) pig manure + NPK. Soil particle size fractions (0-2, 2-10, 10-50 and 50-100 microm) were isolated without chemical pretreatment by ultrasonic dispersion in water followed by sedimentation. The content of total N and forms of organic N in the bulk soil increased after long-term fertilization, and the effect varied with fertilizer type. The plot treated with only mineral fertilizer gave the highest NH3-N and the lowest amino sugar-N content in all treatments. The highest content of amino sugar-N and amino acid-N was found in the treatment of pig manure + NPK. The content (g kg(-1) fraction) of hydrolysable N within size fractions was in the order 0-2 > 2-10 > 50-100 > 10-50 microm, but the contribution of different size fraction to hydrolysable N decreased in the sequence 10-50 > 0-2 > 2-10 > 50-100 microm. Most of the applied mineral fertilizer N that remained in soils was distributed in the particle size fraction < 2 microm while most of the remaining N from manure applied with NPK was transferred into amino sugar-N in each size fraction, and amino acid-N in the size fractions > 2 microm during the process of humification.     

不同来源废水COD、TOC与Cl-的关系

通过对含盐化工废水(A)、受潮汐影响的河流水(B)、城市生活污水处理厂排水(C)、采油废水(D)4种不同来源废水进行为期15 d的采样监测,测定了其COD、TOC和Cl-浓度,分析比较了3种废水指标之间的关系,其中COD分别使用重铬酸钾法、氯气校正法和碘化钾碱性高锰酸钾法3种方法进行测定.实验结果表明,4种废水Cl-浓...     

不同来源废水COD、TOC与Cl^-的关系

通过对含盐化工废水（A）、受潮汐影响的河流水（B）、城市生活污水处理厂排水（C）、采油废水（D）4种不同来源废水进行为期15 d的采样监测,测定了其COD、TOC和Cl^-浓度,分析比较了3种废水指标之间的关系,其中COD分别使用重铬酸钾法、氯气校正法和碘化钾碱性高锰酸钾法3种方法进行测定。实验结果表明,4种废水Cl^-浓度差异较大,盐化工废水A（21749 mg/L）〉采油废水D（7013 mg/L）〉受潮汐影响的河流水B（1807 mg/L）〉城市生活污水处理厂排水C（977 mg/L）;在15 d的监测周期内,盐化工废水（A）的TOC波动较大,其余3种废水的TOC浓度基本保持稳定,与Cl^-浓度变化没有直接的关系;4种不同废水的COD与Cl^-浓度之间具有显著的正相关性。通过分析比较表明,碘化钾碱性高锰酸钾法比较适合于盐化工废水（A）和采油废水（D）的测定,氯气校正法比较适合于城市生活污水处理厂排水（C）和采油废水（D）的测定,受潮汐影响的河流水样（B）波动较大,3种方法测得的COD浓度与Cl^-浓度的变化趋势没有显著差异。TOC较适合表征水质有机污染程度。     

Air pollutant emissions associated with forest,grassland, and agricultural burning in Texas

Outdoor fires, such as wildfires and prescribed burns, can emit substantial amounts of particulate matter and other pollutants into the atmosphere. In Texas, an inventory of forest, grassland and agricultural burning activities revealed that fires consumed vegetation on 1.6 and 1.7 million acres of land, in 1996 and 1997, respectively. Emissions from the fires were estimated based on survey and field data on acres burned and land cover and literature data on fuel consumption and emission factors. Fire data were allocated spatially by county and temporally by month. While fire events can cause high transient air pollutant concentrations, for most criteria pollutants, the fire emissions were a relatively small fraction of the annual emission inventory for the State. For fine particulate matter, however, the annual emission estimates were 40,000 tons/yr, which is likely to represent a significant fraction of the State's emission inventory, especially in the counties where the emissions are concentrated.     

Assessment of elemental composition and properties of copper smelter-affected dust and its nano- and micron size fractions

A comprehensive approach has been developed to the assessment of composition and properties of atmospherically deposited dust in the area affected by a copper smelter. The approach is based on the analysis of initial dust samples, dynamic leaching of water soluble fractions in a rotating coiled column (RCC) followed by the determination of recovered elements and characterization of size, morphology and elemental composition of nano-, submicron, and micron par ticles of dust separated using field-flow fractionation in a RCC. Three separated size fractions of dust (<0.2, 0.2–2, and >2 μm) were characterized by static light scattering and scanning electron microscopy, whereupon the fractions were analyzed by ICP-AES and ICP-MS (after digestion). It has been evaluated that toxic elements, which are characteristics for copper smelter emissions (As, Cu, Zn), are accumulated in fraction >2 μm. At the same time, up to 2.4, 3.1, 8.2, 6.7 g/kg of As, Cu, Zn, Pb, correspondently, were found in nanoparticles (<0.2 μm). It has been also shown that some trace elements (Sn, Sb, Ag, Bi, and Tl) are accumulated in fraction <0.2, and their content in this fraction may be one order of magnitude higher than that in the fraction >2 μm, or the bulk sample. It may be assumed that Sn, Sb, Ag, Bi, Tl compounds are adsorbed onto the finest dust particles as compared to As, Cu, Zn compounds, which are directly emitted from the copper smelter as microparticles.

     

城市污水中有关新型微污染物PPCPs归趋研究的进展

药品和个人护理用品 (PPCPs) 是最近十年引起关注的新型有机微量污染物,其引起的环境安全风险受到人们越来越多的关注。一些研究发现,城市污水处理厂出水中存在着一定浓度的PPCPs,城市污水排放是PPCPs进入环境的一条重要途径。从城市污水中PPCPs的分析方法、迁移转化和减量化技术研究等三个方面综述了有关PPCPs在城市污水中归趋的研究进展,介绍了我国城市污水中PPCPs的研究现状;并对在我国进行相关研究提出了建议,以期推动相关研究的开展。     

北京城区夏季PM2.5及不同组分化学和生物成分分析

为了解北京城区夏季大气颗粒物PM2.5及其不同组分的化学、生物污染特征,于2014年5月末连续采样一个月,采样后超声洗脱并冷冻干燥得到PM2.5颗粒物,在PM2.5颗粒物的基础上制备PM2.5水溶性组分和PM2.5单纯颗粒物,进而对PM2.5颗粒物及另外两种组分样品中的化学及生物成分进行分析测定。结果表明,8种水溶性离子总质量占PM2.5各样品的质量分数依次为67.71%,33.37%,0.09%（依次为PM2.5水溶性组分、PM2.5颗粒物、PM2.5单纯颗粒物,下述数据也按此顺序描述）;16种“酸提”元素总质量占PM2.5各样品的质量分数依次为4.84%,1.86%,0.78%;各样品中内毒素含量分别为0.054 7 EU·mg-1,0.433 3 EU·mg-1,0.041 9 EU·mg-1;PM2.5颗粒物可以检测到细菌16S rDNA、真菌18S rDNA,拷贝量分别为（2.6±1.0）×108个·g-1、（4.3±0.9）×108个·g-1。     

Kinetic aspects and identification of by-products during the ozonation of bitertanol in agricultural wastewaters

The degradation of bitertanol by ozone treatment is investigated. Solutions of bitertanol (8.4 μg mL^?1) were prepared either by dissolution of the standard or by dilution of Gaucho Blé seed loading solution and then ozonated under different conditions. Evolution of the concentrations of bitertanol and its ozonation by-products in both solutions was monitored by HPLC–UV as a function of the treatment time for a concentration of 100 g m^?3 of ozone in the inlet gas. Bitertanol degradation was found to follow a pseudo-first order reaction in both cases. However, the rate of the reaction in diluted seed loading solution was much lower (0.19 vs. 0.27 min^?1 in standard solution) and was close to the reaction rate observed in the presence of a radical scavenger, tert-butanol (0.11 min^?1). Thus, it may be suggested that additives present in the seed loading solution may play the role of radical scavengers. Study of ozone concentration in the inlet gas (from 25 to 100 g m^?3) showed that ozone degradation is also a first-order reaction with respect to ozone. Four ozonation by-products were highlighted, collected and identified by HPLC coupled with an ion trap mass spectrometer using positive electrospray ionization mode. A degradation pathway of bitertanol was finally proposed.