Short-term accumulative signatures of heavy metals in river bed sediments in the industrial area, Tehran, Iran

In modern civilization, numerous anthropogenic activities release a variety of pollutants into the environment and with anomalous enrichment of heavy metals it causes surface and subsurface contamination. The aquatic sediments provide pertinent tools for the quality assessment of urban and industrial environments in large cities. The present study reveals short-term accumulative trends of heavy metals (Co, Cd, and Pb) in the sand and silt dominated riverbed sediments from Chitgar industrial area (Tehran, Iran) between the period of May 2007 and May 2008. Lead demonstrates highest concentration in residential areas, cadmium in and around industrial areas, whereas cobalt shows least variability. Geo-accumulation index implies moderately to highly polluted sediments with respect to Cd and Pb. With few exceptions, all three metals at different sampling stations display short-term increasing trends, independent of seasonal variability with urban and industrial distends along the river being the chief sources of contamination.     

Integrated physicochemical and biological treatment process for fluoride and phosphorus removal from fertilizer plant wastewater

The phosphate fertilizer industry produces highly hazardous and acidic wastewaters. This study was undertaken to develop an integrated approach for the treatment of wastewaters from the phosphate industry. Effluent samples were collected from a local phosphate fertilizer producer and were characterized by their high fluoride and phosphate content. First, the samples were pretreated by precipitation of phosphate and fluoride ions using hydrated lime. The resulting low- fluoride and phosphorus effluent was then treated with the enhanced biological phosphorus removal (EBPR) process to monitor the simultaneous removal of carbon, nitrogen, and phosphorus. Phosphorus removal included a two-stage anaerobic/aerobic system operating under continuous flow. Pretreated wastewater was added to the activated sludge and operated for 160 days in the reactor. The operating strategy included increasing the organic loading rate (OLR) from 0.3 to 1.2 g chemical oxygen demand (COD)/L.d. The stable and high removal rates of COD, NH4(+)-N, and PO4(3-)-P were then recorded. The mean concentrations of the influent were approximately 3600 mg COD/L, 60 mg N/L, and 14 mg P/L, which corresponded to removal efficiencies of approximately 98%, 86%, and 92%, respectively.     

The dependence of the beta coefficient of REA system with dynamic deadband on atmospheric conditions

We simulated the REA system with dynamic deadband to study numerical value and the effect of atmospheric conditions on the empirical constant beta which relates vertical flux to concentration difference between updrafts and downdrafts. We found that the value of beta depends only weakly on the friction velocity and atmospheric stability. In agreement with previous studies, the median value obtained for a system with dynamic deadband proportional to 0.5 times the running mean of the standard deviation of vertical wind speed was beta=0.42+/-0.03. For a single half-hour measurement one has to consider the large uncertainty of +/-0.2. According to our study, the dynamic deadband enables the use of a constant value of beta in flux calculation.     

Leak detection of hydrogen–natural gas mixtures in pipes using the characteristics method of specified time intervals

This paper presents a technique for detection and location of leaks in a single pipe, by means of transient analysis, of hydrogen–natural gas mixtures flows. The method uses transient pressure waves initiated by the sudden closure of a downstream shut-off valve. The presence of a leak in a pipe partially reflects these pressure waves and allows for the location of the leak. Pressure waves are governed by two coupled non-linear, hyperbolic partial differential equations with pressure dependent coefficients. The fluid pressure and velocity are considered as two principal dependent variables. To determine the leak location, the mathematical formulation has been solved by the characteristics method of specified time intervals. The computed results describe the influence of the leak on pressure time-history and the effect of hydrogen mass fraction in the mixture on the leak discharge behaviour. It was found that transient pressure is much important in the case of hydrogen than that in the case of natural gas.     

Standardising and mapping open-source information for crisis regions: the case of post-conflict Iraq

Painting an accurate picture of the situation on the ground in countries in crisis is vital for the efficiency of humanitarian aid and reconstruction agencies. This study describes a method for standardising and mapping the plethora of open-source information. The test site for the study is post-conflict Iraq. Important information on aid distribution, reconstruction and security in Iraq can be derived from the reports of humanitarian aid agencies and the media, before being formatted, inserted into a database and mapped. The product is a visual, cartographic structure of otherwise random information, showing which organisations are working in the country, which thematic and geographic areas are being prioritized in the field, and which areas most frequently experience security events. This type of mapping not only highlights the overall working environment within different parts of the country, but it may also serve as a decision-making tool for donors and humanitarian aid agencies planning to deploy personnel.     

Modification of wood with environmentally friendly chemicals to improve decay resistance

Turkish pine (Pinus brutia Ten.) solid wood was chemically modified to various weight percent gains (WPG) using either acetic, methacrylic, hexanoic and succinic anhydrides. Laboratory soil block decay testing using the brown rot fungus C. puteana and G. trabeum was performed and weight loss calculated. All high degree of modified samples showed good biological resistance and severely reduced degradation. Chemical modification of wood is very important for the prevention of biodeterioration which are environmentally friendly and also not hazardous to human beings.     

Accumulation of Cu,Zn, Cd,and Pb by Scenedesmus obliquus under nongrowth conditions

The aim of this work has been to assess the accumulation of copper, zinc, cadmium and lead by a test alga, Scenedesmus obliquus, under nongrowth conditions. The results provide an evidence that metals can be readily accumulated by algae and that accumulation is a function of the metal-to-algae exposure ratio. When the metals were added in combination in equimolar concentrations, the following order of affinity to algal surface was detected Zn > Cu ? Cd > Pb. However, when EDTA was added to the test water, metal accumulation was greatly retarded. Moreover, when algae loaded with one of the metals were washed with EDTA solution the major part of the accumulated metal was mobilized, indicating that EDTA had stronger metal binding affinity than any ligands liable to exist on algal surface. Metal accumulation by algal cells isolated from a culture in the logarithmic growth phase was of much higher magnitude than that displayed by cells isolated from a culture in the decline phase.     

Environmental Care in Agriculture: A Social Perspective

At its beginning, the European Union’s Common Agricultural Policy (CAP) did not include measures to guide farmers in preserving ecosystems. At the same time, the social context on the 1960s and 1970s did not encourage environmental care to become a priority. Since the 1980s, new social concern expressed alarm over ecology, recognizing that agriculture can pollute. These social changes moved the CAP to add measures that linked agriculture and environment. In order to study if the EU decision-makers have designed a CAP which responds to a new ethic that incorporates environmental care and social demands, two questions rise: whether the social image of agriculture as a polluting activity has changed; and whether farming performs the environmental functions demanded by society. To answer the previous questions, we have reviewed the environmental aspects added to the CAP, then a poll has been conducted and cluster method and classification tree models have been used to group respondents according to their opinions. The results show that the society ascribes great relevance to the environment for the future sustainability of the region, but they are not satisfied with the role of agriculture in producing environmental outputs.     

Deflective effect and the effect of prey detectability on anti-predator function of eyespots

Eyespots (patterns of roughly concentric rings) are often thought to have an anti-predator function. Previous experiments have lent support for the intimidation hypothesis by demonstrating a deterring effect of eyespots, but so far there is little evidence for the deflective effect (direction of attacks toward less vital body parts). We studied predators’ responses towards large and small eyespots and towards prey with no, one, or a pair of eyespots and if this response is influenced by whether or not prey blend into background. In two experiments, we used artificial, triangular prey items and blue tits (Cyanistes caeruleus) as predators. In experiment 1, we found evidence for the deflective effect of small but not large eyespots, independent of whether the prey was presented on a concealing or exposing background. In experiment 2, we found that predators avoided the prey with a pair of small eyespots more than the prey without eyespots, but interestingly, we only found this deterring effect on the concealing background. There was no difference in attacks between the prey with one large and two small or one large and no eyespots. We conclude that deflective function may select for eyespots, and background may influence the deterring function of eyespots.     

Evidence for enhanced dissipation of chlorpyrifos in an agricultural soil inoculated with Serratia rubidaea strain ABS 10

The insecticide ¹⁴C-chlorpyrifos was found mineralized in a Tunisian soil with repeated exposure to it. From this soil, a bacterial strain was isolated that was able to grow in a minimal salt medium (MSM) supplemented with 25 mg L^?1 of chlorpyrifos. It was characterized as Serratia rubidaea strain ABS 10 using morphological and biochemical analyses, as well as 16S rRNA sequencing. In a liquid culture, the S. rubidaea strain ABS 10 was able to dissipate chlorpyrifos almost entirely within 48 h of incubation. Although the S. rubidaea strain ABS 10 was able to grow in an MSM supplemented with chlorpyrifos and dissipate it in a liquid culture, it was not able to mineralize ¹⁴C-chlorpyrifos. Therefore, it can be concluded that the dissipation capability of this bacteria might be attributed to its capacity to adsorb CHL. It can also be ascribed to other reasons such as the formation of biogenic non-extractable residues. In both non-sterile and sterile soil inoculated with S. rubidaea strain ABS 10, chlorpyrifos was more rapidly dissipated than in controls with DT₅₀ of 1.38 and 1.05 days, respectively.