Assessing Settleability of Dry and Wet Weather Flows in an Urban Area Serviced by Combined Sewers

Settleability of dry and wet weather flow samples from a combined sewer system was examined by settling column tests, in order to improve understanding of settling processes and obtain information for design of settling tanks. In fact, these tests mimic the actual settling processes and allow evaluating total suspended solids (TSS) removal by settling. Therefore, it is also possible to assess, indirectly, removals of other pollutants, such as heavy metals, which are generally transported by solid particles in sewage. Towards this end, dry and wet weather flow samples were collected in the Liguori Channel catchment and analyzed in the laboratory for Water Supply and Sewerage (Acquedotti e Fognature) of the University of Calabria for TSS concentrations according to the Standard Methods. The settleability study revealed that removals of TSS in dry weather samples (i.e., sanitary sewage) were greater than in wet weather samples (WW), using the same experimental procedures. In particular, 65% of TSS was removed in dry weather samples at a depth of 3?m for a detention time of 40?min; while in wet weather samples the comparable removal efficiency was less than 60%.     

Ion Fluxes with Bulk and Throughfall Deposition along an Urban–Suburban–Rural Gradient

Fluxes of principal anions and cations with bulk and throughfall deposition during the growing period (April–September) were investigated for three years (2001–2003) at three sites differently exposed to the second biggest Lithuanian city – Kaunas. Fluxes of all investigated anions (SO₄ ^2?, NO₃ ^? and Cl^?) and most cations were found to be the highest in suburban area to compare with both – Rural and urban sites. The highest seasonal variability of monthly ion fluxes and the highest differences between throughfall and bulk fluxes (net throughfall) were recorded in suburban area. The highest throughfall enrichment by sulphur was detected in spring and the beginning of summer (April, May) in urban and especially in suburban sites. For nitrogen compounds (NO₃ ^?, NH₄ ⁺) positive net throughfall values were characteristic for urban and suburban sites and negative for rural site almost during the entire growing period. Uptake of NH₄ ⁺ ions was detected to be much higher of that for nitrates in rural area (46% vs. 22%). The most intensive enrichment of throughfall fluxes by K⁺ ions took place during the summer time (May, June, July), however, intensity of potassium leaching at the same amount of precipitation was the highest in suburban area.     

Fine and Coarse Ionic Aerosol Components in Relation to Wet and Dry Deposition

The distribution of acidic andalkaline constituents (SO₄ ^2-,NO₃ ^-, Cl^-, NH₄ ⁺, Na⁺,K⁺, Ca²⁺) between the fine and coarseparticle range has been examined in an urban locationin Thessaloniki, N. Greece over an 8-month period. The chemistry of wet and dry deposition collected overthe same period was also examined. Statisticalassociations between species within each environmentalphase were investigated using correlation analysis.Use of principal component analysis was made toinvestigate compositional similarities betweenaerosol, deposited dust and rain. It was found thatSO₄ followed by NO₃, NH₄ and Caprevailed in fine aerosol. Sulphates and Ca were alsothe prevailing ions in the coarse particle fraction.Wet deposition was found to be the dominant depositionmechanism for all species. The high dry depositionrates observed for Ca and SO₄ suggest that mostof the dry deposited sulphate is in the form ofCaSO₄. Scavenging ratios of ionic speciesassociated with coarse aerosol were higher than thecorresponding ratios for fine particles. Principalcomponent analysis suggested that variations in ioniccomposition of fine aerosol could be interpretedprimarily by gas-to-particle neutralization reactionsinvolving atmospheric ammonia. In contrast, theinteraction between SO₂ and HNO₃ with Cacompounds seems to be the most likely factor that canexplain variations in wet and dry deposition ioniccontents.     

The Effect of Precipitation Amount and Atmospheric Concentrations on Wet Deposition Fluxes of Oxidized and Reduced Nitrogen Species in Connecticut

The effects of precipitation amount and atmospheric concentrations of inorganic nitrogen species on precipitationconcentrations and wet fluxes of oxidized and reduced nitrogen inConnecticut were studied for a period of 152 weeks (7 February,1997 through 31 December, 1999). The annual volume weighted mean(VWM) concentration in precipitation of oxidized and reducednitrogen varied with precipitation amount between sites andyears. To investigate the effect of varying precipitation amountand mean monthly temperatures on concentrations of inorganicnitrogen species in precipitation, the precipitation events wereclassified into seven groups and each year was divided into twowarm and cold sampling periods. Increasing precipitation amounthad a substantial decreasing effect on the VWM concentration ofnitrate and ammonium ions in precipitation. The highest VWMconcentrations of oxidized and reduced nitrogen in precipitationwere found in the lower weekly precipitation range of 0 to 0.5 cm. The results of this study indicated that precipitationamount was one of the main factors affecting volume weighted meanconcentrations and fluxes of oxidized and reduced nitrogen. Chemical composition of inorganic nitrogen species in theatmosphere showed that during warm and cold sampling periodsreduced nitrogen was the predominant atmospheric specie, andoxidized nitrogen was the predominant wet specie in precipitationat all sampling sites.     

Seasonal Deposition Fluxes of Polycyclic Aromatic Hydrocarbons (PAHs) in Lake Biwa,Japan

Water, Air, & Soil Pollution - The concentrations of Cd, Cu, Fe, Ni, Pb and Zn in the different parts of six bivalves species were determined. From the study conducted, it was found that the...     

上海农村及郊区土壤中PCBs污染特征及来源研究

2007年3月采集上海市农村及郊区36个表层土壤样品,采用气相色谱法对土壤中的多氯联苯（PCBs）残留进行了分析,揭示了土壤中PCBs的残留水平、分布、组成特征及来源。结果表明,试区土壤中共检出62种PCB,总浓度最高2530ng·kg-1,最低71.7ng·kg-1,平均含量534ng·kg-1。较高污染浓度主要是编号为BS2、SJ6、JS4和FX4的土壤样品,但从整体采样区域来看,其污染可能主要来源于城区污染导致的区域大气沉降或是全球大气传输所致。上海农村及郊区土壤PCBs污染物以Tri-CBs和Tetra-CBs为主,主要以工业Aroclor1242来源为主。相关性分析显示,土壤中PCBs与TOC具有显著相关性,尤其是对于挥发性较强的低氯代PCBs,表明TOC是影响上海市土壤中PCBs持留的重要因素之一。聚类分析显示,部分采样点PCBs污染与工业品使用有关,但可能还存在其他来源。     

Dry and Wet Deposition of Nitrogen Emitted in Buenos Aires City to Waters of de la Plata River

Dry and wet deposition of atmospheric nitrogen species (NO₂ and HNO₃) coming from nitrogen oxides emissions in Buenos Aires city to surface waters of de la Plata River were estimated. Atmospheric dispersion models DAUMOD-RD (v.2) and CALPUFF were applied to area and point sources, respectively. These models were run considering 1 year of hourly meteorological data. Emission information included a typical diurnal variation of area source emissions. Annual atmospheric nitrogen (N–NO₂?+?N–HNO₃) deposition to 1,763 km² of the river was 35,600 kg-N year^?1. Dry deposition processes accounted for 89% of this value. The small contribution of wet deposition was a consequence of the very few cases (5%) of rain events during offshore wind conditions. Monthly dry deposition to 1,763 km² of the river varied from 1,628 kg-N month^?1 in February to 3,799 kg-N month^?1 in December, following the monthly occurrence of offshore winds. Monthly wet deposition varied from 1 kg-N month^?1 in June to 1,162 kg-N month^?1 in February. These results came from the combination of favorable conditions for formation of HNO₃ and the occurrence of precipitation during offshore wind situations. Spatial distribution of annual atmospheric N deposition showed a strong coastal gradient. Deposition values reached a maximum of 137.1 kg-N km^?2 year^?1 near the shoreline, which was reduced to the half at 4 km from the coast.     

Wet and Dry Deposition of Sulphur at the Site Melpitz in East Germany. In memorium dedicated to Wolfgang Rolle

Sulphur concentrations in precipitation as sulphate and in air as sulphur dioxide were determined from October 1991 (May 1992), respectively, to December 1995. The total sulphur deposition was calculated from sum of the wet and dry deposition, using the concentration of sulphate and precipitation volume and the concentration and deposition velocity of sulphur dioxide, determined with the micrometeorological gradient method. The concentration of sulphur in precipitation decreased over the period by about 40% and in air about 70%. The wet deposition decreased over the period by about 30%. However there was no decrease in dry deposition despite the reduction in SO₂ concentrations because the deposition velocity varied from 0.16 cm s^-1 to 0.37 cm s^-1 during the period. Therefore no trend was observed in the total sulphur deposition.     

Potential Use of Newly Isolated Bacterial Strain Ochrobactrum anthropi in Bioremediation of Polychlorinated Biphenyls

The effects of urbanization on runoff pollutant concentrations and pollutant loading were studied in three urban catchments of varying imperviousness and land use type in the city of Lahti, Finland. Imperviousness of the catchments were 19 % (“Low”), 62 % (“Intermediate”) and 89 % (“High”). During the 2-year study period, runoff quantity was measured continuously and samples were taken for water quality analysis. Besides imperviousness, land use type strongly affected pollutant concentrations: differences in total phosphorus (tot-P), Al, Cr, Zn and Pb concentrations were observed especially between the city centre catchments (High and Intermediate) and the residential catchment (Low), while total suspended solids (TSS), total nitrogen (tot-N), Mn, Co, Ni and Cu concentrations increased with increasing imperviousness. As for pollutant loads, imperviousness was strongly related to TSS, tot-P, Al, Mn, Zn, Cr, Co, Ni and Cu export. The effects of urbanization on runoff quality were season dependent: urbanization increased runoff volumes and, hence, pollutant loads, especially during warm seasons. Still, highest pollutant export in the catchments occurred during spring. Nevertheless, the warm period produced comparable loads to spring at the city centre catchments. Pollutant concentrations, especially in the city centre catchments, exceeded thresholds set for surface waters, indicating a need for runoff treatment in water quality protection.     

UN ECE ICP Materials: Dose-Response Functions on Dry and Wet Acid Deposition Effects After 8 Years of Exposure

The main results of the International Co-operative Programme on Effects on Materials, including Historic and Cultural Monuments (ICP Materials) within the United Nations Economic Commission for Europe (UN ECE) are summarised. The 8-year field exposure programme involves 39 test sites in 12 European countries and in the United States and Canada. Dose-response functions (DRF) expressing the effect of dry and wet deposition as individual terms have been obtained for a wide range of materials including bronze, copper, weathering steel, zinc, aluminium, nickel, tin, stone materials, paint coatings and glass materials. The DRF's includes parameters that are easily available on different geographical scales and can be used for mapping areas of increased corrosion rates and for calculation of costs.     

Ozone and Nitrogen Dioxide Levels Monitored in an Urban Area (Ciudad Real) in central-southern Spain

This work describes the evolution of NO₂ and O₃ levels from January to December of 2007, covering the four seasonal periods in the urban air of Ciudad Real in the central-southern Spain. The measurements were carried out by means of passive samplers (Radiello® samplers). Eleven samples were collected weekly, placed at different monitoring site locations. The data indicate that the mean levels obtained during this period for O₃ and NO₂ were 38.5?±?3.5 and 20.8?±?3.8 μg/m³, respectively. These measurements were compared with other studies in Ciudad Real. Meteorological conditions (temperature, pressure, humidity relative, wind speed and direction) were also investigated.     

Atmospheric Wet Deposition of Total Phosphorus in New Jersey

Wet deposition of total phosphorus has been measured as part of the New Jersey Atmospheric Deposition Network (NJADN). Precipitation samples were collected in 1999—2001, using automated wet-only precipitation collectors at four sites in New Jersey, representing different land-use regimes. Total phosphorus volume-weighted mean concentrations (VWM) and the wet depositional fluxes were estimated on seasonal and annual timescales. VWM concentrations (± standard error) of total phosphorus ranged from 4.1 ± 0.80 to 15 ± 8.8 μg L^-1 at all sites and were of similar magnitude across the region. The wet deposition flux estimates ranged from 3.9 to 14 mg m^-2 y^-1. VWM concentrations and fluxes were similar to those measured at other locations in the eastern United States.     

青岛大气氮湿沉降动态变化

利用雨量器定点采集雨样的方法,研究青岛市城阳区2007-2010年间降水中不同形态氮浓度、氮沉降量的月、季动态变化。结果表明:降水中NH4+-N、NO3--N、DON月均浓度差异较大。DIN浓度在12月-翌年1月份较高,在7-8月份较低,DON浓度表现为11月份最低;NH4+-N、NO3--N、DON月平均浓度分别为1.26,1.11,1.37mg/L,且均存在冬、春季>夏、秋季的特点。NH4+-N和NO3--N沉降量与降水量呈乘幂型正相关,相关系数(r)平均为0.607,DON沉降量与降水量呈线性正相关(r=0.674),且均达到显著水平(P<0.05)。监测期内各形态氮沉降量月份间变化幅度较大,7-8月份的NH4+-N、NO3--N和DON沉降量分别为4.17,3.00,3.26kg/hm2,约占全年相应形态氮沉降量的44.2%,35.6%,48.6%,且各形态氮沉降量均表现为夏季>春季>秋季>冬季。该区域NH4+-N、NO3--N、DON年沉降量依次为10.14,8.72,6.33kg/hm2,分别占DTN沉降量的40.3%,34.7%,25.0%。     

Genetic Analysis of Black Spruce (Picea mariana) Populations from Dry and Wet Areas of a Metal-Contaminated Region in Ontario (Canada)

Genetic variation and genetic structure of black spruce (Picea mariana L.) populations growing in wet land (lowlands) and dry lands (uplands) with different levels of metal contaminations were analyzed using ISSR. Polymorphic loci (P%) ranged from 65% to 90% with a mean of 75%. Nei??s gene diversity (h) varied from 0.264 to 0.359 with a mean of 0.310, and Shannon??s index (I) ranged from 0.381 to 0.524 with a mean of 0.449. The level of genetic variation was higher in populations from wet lands than those from dry lands. Variation within populations accounts for most of total genetic variation. The genetic distance among the black spruce (P. mariana) populations ranged from 0.171 to 0.351. The present study indicates that genetic variation and long-term exposure to metals (more than 30 years) are not associated. Cytological analysis of black spruce seeds from metal-contaminated and -uncontaminated areas showed normal mitotic behavior during prophase, metaphase, anaphase, and telophase.     

Deposition and Emission Fluxes of Acidifying Compounds on the Territory of Belarus

In the paper trends of precipitates acidity, acidifying compounds wet deposition and emission on the territory of Belarus in the last decade are considered. Trend of acidity of precipitates in 90th on the territory of Belarus was detected. But at the same time heterogeneity of measurement sites was revealed. For 90th statistically approved trend of sulphur deposition reduction have been showed. The intensity of deposition of nitrates has great heterogeneity. Levels of deposition of sulphur and nitrogen on the territory of Belarus in the long-term scale as a whole correlate with levels of SO₂ and NO_x emission on territory of Europe. This is due to the fact that peculiarities of geographical situation of Belarus have caused prevalence of transboundary component in structure of atmospheric depositions.     

维生素E和槲皮素对多氯联苯引起的鸡胚肝细胞损伤的缓解作用

利用体外培养的鸡胚肝细胞研究抗氧化剂维生素E(vitamin E)和槲皮素(quercetin)对多氯联苯(polychlorinated biphenyls，PCB)引起的肝细胞损伤的缓解作用。取14d的艾维茵鸡胚的肝脏，用胶原酶消化分离成单个肝细胞并进行培养。实验分对照组、PCB组(剂量为0．01～10μg/mL)、维生素E或槲皮素组(剂量为0．1-10μg／mL)和维生素E或槲皮素 PCB(10μg／mL)组。药物处理48h后用四甲偶氮唑蓝(MTT)法测定肝细胞的存活率。结果显示：在无血清培养液中鸡胚肝细胞呈多角形，成片生长，可存活1周以上。不同剂量的PCB组均可抑制肝细胞的增殖并引起细胞的部分死亡，高于0．1μg/mL的PCB能引起肝细胞明显死亡；维生素E和槲皮素组的肝细胞保持与对照组相似的形态，与PCB共同处理组中0．1μg/mL的维生素E或槲皮素可显著抑制PCB引起的细胞损伤，使细胞保持比较完整的外形，但剂量较低时作用不显著。结果表明离体培养的鸡胚肝细胞可作为肝损伤的细胞模型，PCB对培养的肝细胞的损伤及抗氧化剂维生素E和槲皮素对它的缓解作用提示，PCB对肝细胞的损伤可能是通过诱导细胞膜发生脂质过氧化而导致细胞的死亡。     

Dry Deposition to the Forest Canopy and Surrogate Surfaces in Two Mediterranean Holm Oak Forests in Montseny (NE Spain)

The fluxes recovered from washing branches and surrogatesurfaces were compared for two holm oak (Quercus ilex L.)forests in the Montseny mountains (NE Spain) differentiallyexposed to pollution. For 5 periods in May and June 1996 afterexposures ranging between 68–189 hr, 6 metacrylate plates and 8branches were extracted with distilled water. Also, a sequentialwashing of branches was undertaken, with 5 min separationsbetween the 3 initial washes, one hour between the 3rd and the4th, and 6 hr between the 4th and the last one. The compositionwas analysed for PO₄ ^3-, SO₄ ^2-,NO₃ ^-, Cl, F, NH₄ ⁺,Ca²⁺, Mg²⁺, Na⁺, K⁺, Cu, Pb, Mn, Co, Ni and Zn. The applied techniques were consistent in that dry deposition would accountfor the throughfall fluxes of NO₃ ^-, Cl^-,Cu and Zn. Potassium and Mn would derive mostly from leaching and their fluxes were strongly related with the holm oak flower growth. ForMg²⁺ and SO₄ ^2- either leaching or impaction of small particles or gases (for SO₄ ^2-) could account forthe recovered fluxes. Also for Na⁺ and Ca²⁺ the experiments did not produce conclusive results. Ammonium, F, Pb,Co, and Na were under the detection limit of analyticaltechniques in the plate-wash. The exposed site presented higherleaf-wash and plate-wash fluxes for all elements. This wasattributed to its higher exposure to pollutants, and forleaching-derived elements, to its higher site fertility.     

Survey of polychlorinated dibenzo-p-dioxins (PCDDs), Polychlorinated Dibenzo-p-furans (PCDFs), polychlorinated biphenyls (PCBs), and mineral components in Italian citrus cold-pressed essential oils

Investigation of PCDDs, PCDFs, PCBs, Al, As, Pb, Ba, Co, Cu, Cr, Fe, Mn, Cd, Ag, Sn, Zn, and Hg contents in 60 samples of cold-pressed essential oils produced in Calabria and Sicily in 2003-2005 was carried out. PCDDs, PCDFs, and PCBs were analyzed by HRGC-HRMS techniques using U.S. EPA 1613/94 and U.S. EPA 1668/A (1999) analytical methods. Mineral components were determined through GFAAS techniques; Hg content was determined by FI-M/H-AAS. The results of this study showed that essential oil contamination was due to a widespread pollution, typical background of rural areas, with relatively higher concentrations of PCDDs compared to PCDFs and little presence of PeCDF. Congeners OCDD, HpCDF, and OCDF were found at high concentrations. Regarding mineral components, mean values of Cr, Fe, and Ni were in agreement with data reported in the literature. Concentrations of As and Pb were below the maximum limits accepted by the current legislation. Finally, none of the samples analyzed were contaminated with Hg.     

Modeling Effects of Changing Deposition and Forestry on Nitrogen Fluxes in a Northern River Basin

The application of a new, spatial nitrogen leaching/retention model N_EXRET to the Oulujoki river basin (22800 km²) in Finland is discussed. The model utilizes remote sensing-based land use and forest classification and evaluated export coefficients obtained from detailed small catchment studies. The present and future N depositions were estimated with the regional deposition model DAIQUIRI. Based on source apportionment, N deposition, forestry and agriculture each contribute 16–17% of the total export, with pronounced variation between the different sub-basins. The effect of changing forestry and deposition on N fluxes is assessed by using N deposition scenarios based on recent international emission reduction agreements.