High-frequency measurements reveal spatial and temporal patterns of dissolved organic matter in an urban water conveyance

Stormwater runoff in urban areas can contribute high concentrations of dissolved organic matter (DOM) to receiving waters, potentially causing impairment to the aquatic ecosystem of urban streams and downstream water bodies. Compositional changes in DOM due to storm events in forested, agricultural, and urban landscapes have been well studied, but in situ sensors have not been widely applied to monitor stormwater contributions in urbanized areas, leaving the spatial and temporal characteristics of DOM within these systems poorly understood. We deployed fluorescent DOM (FDOM) sensors at upstream and downstream locations within a study reach to characterize the spatial and temporal changes in DOM quantity and sources within an urban water conveyance that receives stormwater runoff. Baseflow FDOM decreased over the summer season as seasonal flows upstream transported less DOM. FDOM fluctuated diurnally, the amplitude of which also declined as the summer season progressed. During storms, FDOM concentrations were rapidly elevated to values orders of magnitude greater than baseflow measurements, with greater concentrations at the downstream monitoring site, revealing high contributions from stormwater outfalls between the two locations. Observations from custom, in situ fluorometers resembled results obtained using laboratory methods for identifying DOM source material and indicated that DOM transitioned to a more microbially derived composition as the summer season progressed, while stormwater contributions contributed DOM from terrestrial sources. Deployment of a mobile sensing platform during varying flow conditions captured spatial changes in DOM concentration and composition and revealed contributions of DOM from outfalls during stormflows that would have otherwise been unobserved.     

Study of electromagnetic radiation pollution in an Indian city

Electromagnetic radiation emitted by cell phone towers is a form of environmental pollution and is a new health hazard, especially to children and patients. The present studies were taken to estimate the microwave/RF pollution by measuring radiation power densities near schools and hospitals of Chandigarh city in India. The cell phone radiations were measured using a handheld portable power density meter TES 593 and specific absorption rates were estimated from the measured values. These values of electromagnetic radiation in the environment were compared with the levels at which biological system of humans and animals starts getting affected. The values were also compared with the international exposure limits set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). The highest measured power density was 11.48?mW/m(2) which is 1,148% of the biological limit. The results indicated that the exposure levels in the city were below the ICNIRP limit, but much above the biological limit.     

A new method for municipal solid waste incinerator (MSWI) fly ash inertization, based on colloidal silica

Municipal solid waste incineration (MSWI) is a straightforward way to manage waste, however the disposal of process byproducts, mainly bottom and fly ash, is still a problem, because of their hazardous contents. Fly ash is a byproduct of many other processes that involve combustion to produce energy. In this paper we present and discuss a new method for MSWI fly ash inertization, mainly based on the use of colloidal silica as a stabilization agent for metals. In the patented procedure, fly ash of different provenance can be used to produce an inert and non-hazardous material, that can be reused. In fact to make the recovery process more efficient, landfilling should be totally avoided. For this reason, to enhance the possibility of reuse, a washing process, for salts recovery, is proposed as a final step of the inertization procedure. The obtained inert material is called COSMOS (COlloidal Silica Medium to Obtain Safe inert), and it is composed of calcium carbonate, calcium sulfate, silicon oxide and a wide quantity of non-soluble amorphous compounds. COSMOS does not contain any corrosive salts. This makes it extremely interesting for cement industry applications with several other advantages, and environmental benefits. The new proposed inertization procedure appears very promising, because it allows MSWI fly ash to be considered a valuable resource. Thanks to the obtained results, a demonstration project, in the frame of LIFE+, has been funded by the European Commission (LIFE+ 2008 project ENV/IT/000434, ).     

Changing environment and urban identity following open-cast mining and thermic power plant in Turkey: case of Soma

This paper is a summary of a project changed into a book named by “Changing Environment, City and Identity in Soma with the Geographical Evaluations” issued on May 2005. In this research, Soma, which is one of the most remarkable districts in Manisa in the West Anatolia from the point of economical figures, is assessed with its physical environment potential, improving economical activities and changing socio-economical structure. Owing to the open coal basins in the northeast and southwest of the district where lignite is produced and the impact of the thermic power plant near the city centre, Soma has changed on a large scale. This change has introduced some environmental problems into the district such as the devastation of the forestry land; the infertility of farming land; and soil, water and air pollution. Even though the change under discussion has led to many problems to deal with, it has also influenced its socio-economical structure to a large extent and revealed new type of inhabitants having different life expectations and aims. In conclusion, in this article, changing environment and city structure after lignite processing and thermic station establishment in Soma are discussed through the effective geographical factors. The new city profile formed by the local dynamics in question is evaluated according to the data obtained by the studies made in the neighbourhood.     

Some considerations on the use of simple box models of contaminant fate in soils

A simple box model computing time-averaged concentrations in soil and water of contaminants such as pesticides, following a pulse emission under the assumption of constant removal rates, is presented and evaluated against a benchmark model and some lysimeter experiments representative of different soil and climate settings in Europe. The simple box model allows capturing to some extent the trends of contaminant releases observed from lysimeters or predicted by the benchmark model. This suggests that the correct order of magnitude of environmental concentrations and loads of contaminants can be described as a first approximation by a very simple back-of-the-envelope calculation. In the calculation, the time lag between contaminant application and the start of runoff or leaching should be considered. In the absence of more detailed information, repeating the calculation for the extreme cases of zero and one month lag yields a reasonably realistic range, and the geometric mean of the two is suggested as a first guess estimate. This configures a practical approach for the screening of contaminant losses especially suited for the mapping of predicted environmental concentrations (PECs) for assessment at broad scale (such as continental Europe, a country or a large catchment), where contingent determinants of contaminant fate tend to be averaged out and use of more detailed models usually promises to yield little improvement of PECs.     

Household water insecurity and its cultural dimensions: preliminary results from Newtok,Alaska

Using a relational approach, I examine several cultural dimensions involved in household water access and use in Newtok, Alaska. I describe the patterns that emerge around domestic water access and use, as well as the subjective lived experiences of water insecurity including risk perceptions, and the daily work and hydro-social relationships involved in accessing water from various sources. I found that Newtok residents haul water in limited amounts from a multitude of sources, both treated and untreated, throughout the year. Household water access is tied to hydro-social relationships predicated on sharing and reciprocity, particularly when the primary treated water access point is unavailable. Older boys and young men are primarily responsible for hauling water, and this role appears to be important to male Yupik identity. Many interviewees described preferring to drink untreated water, a practice that appears related to cultural constructions of natural water sources as pure and self-purifying, as well as concerns about the safety of treated water. Concerns related to the health consequences of low water access appear to differ by gender and age, with women and elders expressing greater concern than men. These preliminary results point to the importance of understanding the cultural dimensions involved in household water access and use. I argue that institutional responses to water insecurity need to incorporate such cultural dimensions into solutions aimed at increasing household access to and use of water.     

Two sampling strategies for an overview of pesticide contamination in an agriculture-extensive headwater stream

Two headwaters located in southwest France were monitored for 3 and 2 years (Auvézère and Aixette watershed, respectively) with two sampling strategies: grab and passive sampling with polar organic chemical integrative sampler (POCIS). These watersheds are rural and characterized by agricultural areas with similar breeding practices, except that the Auvézère watershed contains apple production for agricultural diversification and the downstream portion of the Aixette watershed is in a peri-urban area. The agricultural activities of both are extensive, i.e., with limited supply of fertilizer and pesticides. The sampling strategies used here give specific information: grab samples for higher pesticide content and POCIS for contamination background noise and number of compounds found. Agricultural catchments in small headwater streams are characterized by a background noise of pesticide contamination in the range of 20–70 ng/L, but there may also be transient and high-peak pesticide contamination (2000–3000 ng/L) caused by rain events, poor use of pesticides, and/or the small size of the water body. This study demonstrates that between two specific runoff events, contamination was low; hence the importance of passive sampler use. While the peak pesticide concentrations seen here are a toxicity risk for aquatic life, the pesticide background noise of single compounds do not pose obvious acute nor chronic risks; however, this study did not consider the risk from synergistic “cocktail” effects. Proper tools and sampling strategies may link watershed activities (agricultural, non-agricultural) to pesticides detected in the water, and data from both grab and passive samples can contribute to discussions on environmental effects in headwaters, an area of great importance for biodiversity.     

Photocatalytic reduction of carbon dioxide over Cu/TiO<Subscript>2</Subscript> photocatalysts

The photocatalytic reduction of CO₂ with H₂O was investigated using Cu/TiO₂ photocatalysts in aqueous solution. For this purpose, Cu/TiO₂ photocatalysts (with 0.2, 0.9, 2, 4, and 6 wt.% of Cu) have been synthesized via sol-gel method. The photocatalysts were extensively characterized by means of inductively coupled plasma optical emission spectrometry (ICP-OES), N₂ physisorption (BET), XRD, UV-vis DRS, FT-IR, Raman spectroscopy, TEM-EDX, and photoelectrochemical measurements. The as-prepared photocatalysts contain anatase as a major crystalline phase with a crystallite size around 13 nm. By increasing the amount of Cu, specific surface area and band gap energy decreased in addition to the formation of large agglomeration of CuO. Results revealed that the photocatalytic reduction of CO₂ decreased in the presence of Cu/TiO₂ in comparison to pure TiO₂, which might be associated to the formation of CuO phase acting as a recombination center of generated electron-hole pair. Decreasing of photoactivity can also be connected with a very low position of conduction band of photocatalysts with high Cu content, which makes H₂ production necessary for CO₂ reduction more difficult.