Water, Air and Soil Pollution: Focus

This work presents the first results of a study concerning on-road and in-vehicle exposure to particulate matter in the area of Athens. PM10 concentration measurements were conducted by TSI DustTrak, while driving along routes with different characteristics of traffic density, during September 2003–March 2004. Concurrent measurements of the ultrafine particles (UFPs) number concentration were also conducted, by condensation particle counter during part of the days. Pedestrian exposure to PM10 and UFPs was also studied through stationary measurements on the kerbside of selected roads on November 2003 and February 2004. A major avenue, a heavy-trafficked road across a children hospital and two central roads, one in a residential and one in a commercial area were selected for measurement. The results indicate that every day commuters are exposed to significant concentration levels. Higher exposures were observed in heavy-trafficked areas and during rush hours. Mean PM10 in-vehicle and on-road concentrations ranged from 30–320 μg/m3 and 70–285 μg/m3, respectively. The ultrafine particles number concentrations were in the range of 5.0 × 104–17.3 × 104 particles/cm3 in-vehicle and 3.1 × 104–7.3 × 104 particles/cm3 on the kerbside of a central residential road. Both PM10 and UFPs concentrations presented repeated short-term peak exposures. The results clearly point out the importance of the road microenvironment (in-vehicle and on kerbside) for population exposure in urban areas.

Measurements of TotHg (total mercury) and MeHg (methylmercury) in runoff from the covered catchment G1 and the reference catchment F1 at Lake Gårdsjön, Sweden, have been performed and evaluated. The roof over the covered catchment limits atmospheric deposition input of TotHg and MeHg and a response in runoff concentrations and transport was expected. Based on data from 10 yr of monitoring, no statistically significant change in runoff flux of TotHg or MeHg can be observed. A slight decrease in MeHg output in the covered catchment was observed after 2 yr of the experiment. This can be explained as a temporary effect caused by the roof construction. The main conclusion is that release of TotHg and MeHg from the forest soil is controlled by factors other that wet deposition input, for example the mineralisation of organic matter. Furthermore, there is no indication of a depletion of the Hg pool in the soil. In spring 1999, the reference catchment F1 was affected by forestry machinery significantly disturbing the forest soil layer in a limited area. This caused MeHg concentrations to increase dramatically in runoff and led to an increase of the annual transport by at least a factor of 3. This indicates that forestry and other activities that disturb forest soils may be important for controlling MeHg fluxes to aquatic ecosystems.

Future (24 h later) daily ground level SO2 concentration in Istanbul was modeled and predicted using a new and powerful technique, Artificial Neural Networks (ANN) in the case of meteorological parameters as input variables. Results show that the trend of SO2 from higher values in winter to lower values in spring and summer, and again to higher values towards winter can be correctly represented by the neural networks. The model better predicted the lower SO2 values in spring and summer seasons when compared to higher values in winter season because of the pattern distribution in training data sets. Beside the amount of the database, the more the variation of the values of the parameters in their own ranges, the more the network learns the database. As a result of this study, considerably successful results were obtained when considering the complex and nonlineer structure of the atmosphere, which is the source of the database.

Lượng chất dinh dưỡng dễ hòa tan trên bề mặt bãi đậu xe nhựa đường đã được đo tại bốn vị trí ở khu vực đô thị Phoenix, Arizona, Hoa Kỳ. Sử dụng mô phỏng mưa, các sự kiện mưa ngắn và mạnh đã được tạo ra để mô phỏng dòng chảy 'rửa trôi đầu tiên'. Mẫu được thu thập từ các mảng 0,3 m2 bề mặt nhựa đường tại 8 đến 10 địa điểm trên mỗi bãi đậu xe, trong mùa trước mùa mưa vào tháng 6 đến tháng 7 năm 1998 và được phân tích cho NO3--N hòa tan, NH4+-N, phosphate phản ứng hòa tan (SRP), và carbon hữu cơ hòa tan (DOC). Nồng độ dòng chảy thay đổi đáng kể cho NO3--N và NH4+-N (giữa 0,1 và 115,8 mg L-1) và DOC (26,1 đến 295,7 mg L-1), nhưng ít hơn cho SRP (0,1 đến 1,0 mg L-1), đại diện cho tải trọng bề mặt trung bình lần lượt là 191,3, 532,2 và 1,8 mg m-2. So với dữ liệu tương tự thu thập từ bề mặt đất sa mạc chưa được phát triển bên ngoài thành phố, tải trọng NO3--N và NH4+-N trên bề mặt nhựa đường lớn hơn lần lượt 91 và 13 lần. Ngược lại, tải trọng SRP cho thấy ít sự khác biệt giữa bề mặt nhựa đường và sa mạc. Lưu lượng dinh dưỡng trong dòng chảy từ một cơn bão xảy ra ngay sau các thí nghiệm đã được sử dụng để ước tính ngân sách đầu vào - đầu ra cho 3 bãi đậu xe trong nghiên cứu. Các đầu ra đo lường của DOC và SRP tương tự như những gì được dự đoán bằng cách sử dụng lượng mưa và tải trọng bề mặt xác định qua thực nghiệm, nhưng đối với NH4+-N và đặc biệt là NO3--N, đầu vào mưa ước tính và dòng chảy bề mặt cao hơn đáng kể so với xuất khẩu trong dòng chảy. Điều này cho thấy rằng các bãi đậu xe có thể là những địa điểm quan trọng cho việc tích lũy và lưu trữ tạm thời chất dinh dưỡng trong các vùng đô thị khô cằn.

Aqueous phase adsorption of three textile dyes onto a granular activated carbon produced from acid activation of almond shells is presented. Primarily, the sorption of three basic dyes, methylene blue, rhodamine b, and malachite green oxalate were studied. Four models, the Freundlich, the Langmuir, the Redlich-Peterson, and the Toth isotherms were compared for their quality of fit to the single-solute sorption data. Next, sorption of the three likely binary systems was examined. Four bi-solute models, the extended Langmuir with and without an interaction term, the extended Redlich-Peterson with an interaction term, and the empirical extended Freundlich model were used to predict sorption in the binary systems. Nonlinearly determined constants of the corresponding single-solute isotherms were used in the binary models to compare with experimental binary sorption data. For the single-solute system, the three-parameter models of the Redlich-Peterson and the Toth isotherms outperformed the Langmuir and Freundlich models. The empirical extended Freundlich model produced the closest comparison to the binary data in each system. In general, the nonlinear method provided a simple and computationally effective technique of producing optimal fitting parameters for the bi-solute sorption models.

Kalymnos is one of the largest islands of the Dodecanese, a rather dense island complex situated at the southeast corner of Europe. The development potential of the area is large. A serious restrictive factor, though, is fresh water availability. The latter has declined in the last few years, due to increase in population and in per capita water demand. As a result, the already stressed groundwater resources have been overexploited, and salinization of many coastal aquifers has already taken place. Since water import from other areas is not a sustainable solution, optimization of the management of local water resources is necessary. This paper deals with both sides of the water balance of Kalymnos. First an estimate of the evolution of water demand is discussed. The use of a GIS tool, in order to estimate renewable water resources at the hydrologic basin scale, is presented next. Conjunctive use of surface and ground water resources, including traditional rainwater collection, is proposed. Water resources development in the hydrologic basin of Vathy, which is one of the largest of the island, is discussed in more detail.

High concentration of Hg, less volatile PCB congeners and p,p′-DDE in Arctic charr from an arctic lake was mainly causedby biomagnification in the food chain where cannibalism was thedriving force. We suggest that low sediment fluxes of Hg, low net production of methyl mercury, and short food chains excludingpiscivory explain the low levels of Hg in the invertebrate feeding fish population in five European high mountain lakes.Concentrations of less volatile PCB congeners in insectivorous fish populations from the European high mountain lakes were mainly influenced by fish age and atmospheric deposition, indicated by the sediment inventory. Atmospheric deposition influenced by local sources may explain the higher concentrationsof pesticides (p,p′-DDT, p,p′-DDE and γ-HCH) observedin fish from the Pyrenees compared to the other sites. Theconcentrations of Hg and organochlorines did not exceedthe guidelines for fish consumption, except for Hg levelsin the oldest fish from the arctic lake.

Critical load exceedances have been used as an effects-related parameter for guiding international air emission control negotiations. High-resolution critical load data are combined with low-resolution deposition data.This article shows that doing so systematicallyunderestimates `true' critical load exceedances as obtainedfrom combining critical load and deposition data of identicalhigh spatial resolution. 95th percentile critical loadexceedances in EMEP grids based on high resolution depositiondata are 60 and 150% higher (mean values for nutrientnitrogen and acidity, respectively) than critical loadexceedances based on the low resolution EMEP depositionmodel. The latter are used in international negotiations. Differences in individual EMEP grid squares vary betweeninsignificantly different from zero and 340%, depending onregional deposition and critical load characteristics andcritical load types (nutrient nitrogen versus acidity).Exceedances based on high-resolution deposition values arealso compared to EMEP grid averages of these values forforests only. This comparison excludes the effect ofsystematically higher depositions to forests. Still, thescale difference of (averaged, low-resolution) deposition and(high-resolution) critical loads data yields underestimatesof the 95th percentiles by on average ca. 20%.These systematic errors due to the scale dependence should beborne in mind when interpreting effects of internationalemission control measures.