Effects of treated sewage sludge levels on temporal variations of some soil properties of a Typic Xerofluvent soil in Menemen Plain, Western Anatolia, Turkey

The aim of this study is to determine effects of treated sewage sludge (TSS) levels as an organic matter (OM) resource on temporal variations of some soil properties of a Typic Xerofluvent soil. The experiment was conducted in Menemen Plain, in the Western Anatolia Region of Turkey (latitudes 38 degrees 34'48.22'-38 degrees 34'49.24' N; longitudes 27 degrees 1'23.05-27 degrees 1'24.14' E) in the years of 2003 and 2004. Moist TSS was added to the soil at the rates of 0, 30, 60 and 90 t ha(-1) on May 1, 2003. Peanut (Arachis hypogaea) was planted as first crop. On the other hand, mixture of green barley (Hordeum vulgare) and common vetch (Vicia sativa L.) was planted as second crop. During the experiment, soil samples were taken in five different periods (1st, June 18, 2003; 2nd, November 13, 2003; 3rd, April 30, 2004; 4th, October 10, 2004 and 5th, May 12, 2004). The results showed that increasing TSS application to Typic Xerofluvent soil was significantly increased total salt, OM, total porosity, micro porosity, macro porosity, field capacity, wilting point, available water content, structure stability index and aggregation percentage values of soil when compared with control. Meanwhile, particle density, dry bulk density and nonaggregated silt + clay values of soil decreased. On the other hand, soil reaction (pH), lime content and total silt + clay values of soil did not significantly change. In the course of time, depending on decomposing of TSS organic materials in soil, effect of TSS levels on soil properties decreased particularly in the last periods. For this reason, it can be recommended that 90 t ha(-1) moist TSS can be added once in 2 years for improving soil properties of Typic Xerofluvent soil, which are characterized by low OM content.     

Distribution of vehicular pollutants in street canyons of Varanasi, India: a different case

In present study horizontal and vertical distribution of traffic-related pollutants (CO and SO(2)) within the street canyons in (CO and SO(2)) Varanasi, India was monitored. The results showed that average horizontal profiles of traffic-related pollutant concentrations within street canyon at leeward side were approximately same as that of windward side. However, the vertical concentration of both the pollutants decreases with height above the ground and study indicated that CO and SO(2) concentrations at different heights below the roof showed clear vertical self-gradient. CO and SO(2) concentration decreased with height and the minimum value occurred at the roof. It was concluded from the observed results that pollutants from vehicular exhaust emissions in the street canyon of Varanasi were evenly distributed. This result may be due to the fact that wind vortices are not formed. Therefore, urban planners can use this type of streets so that there is proper ventilation and dispersal of pollutants.     

The Statistical Investigation on Posidonia Oceanica (L.) Delile Meadows in Izmir, Turkey

In this study, variance analysis technique on unbalanced data was examined, and in this sense, Type II (fitting constants) methods were studied. The aim of this study was to show that meaningful evaluations can be performed even in unbalanced conditions and to contribute to the present investigations in biological area. In the implementation part of the study, the juvenile leaf densities of Posidonia oceanica—which is a sea grass that grows in Izmir Bay, and has very important ecological effects—in various regions and in various depths were determined. The results revealed that depth affect number of juvenile leaf (d.f.?=?3, F?=?523.90, R ²?=?0.998, p?F?=?41.53, p?F?=?19.65, p?p?p?p?p?相似文献   

Effects of environmental methylmercury on the health of wild birds, mammals, and fish

Wild piscivorous fish, mammals, and birds may be at risk for elevated dietary methylmercury intake and toxicity. In controlled feeding studies, the consumption of diets that contained Hg (as methylmercury) at environmentally realistic concentrations resulted in a range of toxic effects in fish, birds, and mammals, including behavioral, neurochemical, hormonal, and reproductive changes. Limited field-based studies, especially with certain wild piscivorous bird species, e.g., the common loon, corroborated laboratory-based results, demonstrating significant relations between methylmercury exposure and various indicators of methylmercury toxicity, including reproductive impairment. Potential population effects in fish and wildlife resulting from dietary methylmercury exposure are expected to vary as a function of species life history, as well as regional differences in fish-Hg concentrations, which, in turn, are influenced by differences in Hg deposition and environmental methylation rates. However, population modeling suggests that reductions in Hg emissions could have substantial benefits for some common loon populations that are currently experiencing elevated methylmercury exposure. Predicted benefits would be mediated primarily through improved hatching success and development of hatchlings to maturity as Hg concentrations in prey fish decline. Other piscivorous species may also benefit from decreased Hg exposure but have not been as extensively studied as the common loon.     

Spatial and temporal variations and possible sources of dichlorodiphenyltrichloroethane (DDT) and its metabolites in rivers in Tianjin, China

Water, suspended solid (SS) and sediment samples were collected from nine water courses in Tianjin, China and analyzed for dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDXs, including o,p'-,p,p'-DDT, DDD and DDE). The average DDX concentrations in water, SS and sediment were 59+/-30 ng l(-1), 2690+/-1940 ng g(-1)dry wt. and 340+/-930 ng g(-1)dry wt., respectively. Due to the termination of the extensive agricultural application and industrial manufacture, DDXs in river sediment decreased by one order of magnitude since 1970's and low DDT fractions in these sediments were observed. Still, DDXs in the sediments near the outlets of the major manufacturers remained relatively high attributed to the historic input. DDXs in sediment were also positively correlated with organic matter content. Spatial distributions of DDXs in SS and water was different from that in sediment. For SS, a negative correlation between DDX concentration and SS content indicated a dilution effect in many rivers. Dissolved organic carbon content was the major factor affecting DDX concentrations in water phase. Wastewater discharged from dicofol manufacturers and likely illegal agricultural application were the primary reasons causing high DDT (DDE+DDD) ratios in SS and water.     

Comparison of lead residues among avian bones

To determine if significant differences exist in lead (Pb) accumulation in different bones, especially those most often used for bone-Pb studies in wildlife, we compared Pb concentrations in radius, ulna, humerus, femur, and tibia of Common Eider (Somateria mollissima); and radius/ulna (combined), femur, and tibia of American Woodcock (Scolopax minor). There were no significant differences in bone-Pb concentrations among woodcock bones over a wide range of Pb concentrations (3-311 microg/g). In eider, where bone-Pb concentrations were low (<10 microg/g), leg bones had significantly higher Pb concentrations (approximately 30-40%) than wing bones from the same individuals. The variation among individual birds was greater than the variation among different bones within a bird. Based on our findings, we conclude that one type of bone may be substituted for another in bone-Pb studies although the same bone type should be analyzed for all birds within a study, whenever possible.     

Phosphorus supply influences heathland responses to atmospheric nitrogen deposition

On an upland moor dominated by pioneer Calluna vulgaris and with an understorey of mosses and lichens, experimental plots were treated with factorial combinations of nitrogen (N) at +0 and +20kg Nha(-1)yr(-1), and phosphorus (P) at +0 and +5kg Pha(-1)yr(-1). Over the 4-year duration of the experiment, the cover of the Calluna canopy increased in density over time as part of normal phenological development. Moss cover increased initially in response to N addition but then remained static; increases in cover in response to P addition became stronger over time, eventually causing reductions in the cover of the dominant Calluna canopy. Lichen cover virtually disappeared within 4 years in plots receiving +20kg Nha(-1)yr(-1) and also in separate plots receiving +10kg Nha(-1)yr(-1), but this effect was reversed by the addition of P.     

Challenges in quantifying biosphere-atmosphere exchange of nitrogen species

Recent research in nitrogen exchange with the atmosphere has separated research communities according to N form. The integrated perspective needed to quantify the net effect of N on greenhouse-gas balance is being addressed by the NitroEurope Integrated Project (NEU). Recent advances have depended on improved methodologies, while ongoing challenges include gas-aerosol interactions, organic nitrogen and N(2) fluxes. The NEU strategy applies a 3-tier Flux Network together with a Manipulation Network of global-change experiments, linked by common protocols to facilitate model application. Substantial progress has been made in modelling N fluxes, especially for N(2)O, NO and bi-directional NH(3) exchange. Landscape analysis represents an emerging challenge to address the spatial interactions between farms, fields, ecosystems, catchments and air dispersion/deposition. European up-scaling of N fluxes is highly uncertain and a key priority is for better data on agricultural practices. Finally, attention is needed to develop N flux verification procedures to assess compliance with international protocols.     

Effect of Fe (III) on acid degradation of methylparathion

A study was undertaken to determine the transformation kinetic of methylparathion (O, O, -dimethyl O-4 nitrophenylphosphorotioate) in the presence of Fe(III) between pH 2 and 7. The Fe(III) was not electroactive under the conditions used in this study, and polarographic signals were exhibited by methylparathion and main degradation product only. Data suggest that hydrolysis of methylparathion in an acid medium is catalyzed by Fe(III) and the pesticide did not degrade in this medium without this cation. Methylparathion degradation was observed at all the pHs studied and was independent of the predominant chemical form of Fe(III) in the aqueous medium. The reaction was first-order with pH-dependent rate constant (k) values ranging from 3.3 x 10(- 3) h(- 1) to 7.0 x 10(- 3) h(- 1). The k values increased as pH decreased, suggesting that Fe(III) acted as an electrophile in the reaction mechanism.