Investigation of wind erosion process for estimation, prevention, and control of DSS in Yazd–Ardakan plain

Wind erosion is a phenomenon that is reasonably common in regions where dry winds blow. For the most part, these regions correspond to the dry lands; areas where the soil, generally, is dry and shifting and lacks vegetation for most of the year. The winds are sufficiently strong to lift and move sands and soil particles. The repeated removal of superficial layers by the action of winds can modify the texture of the topsoil, by removing the fine particles and leaving the larger particles. Dust and sandstorm (DSS) is the generic term for a serious environmental phenomenon that involves strong winds that blow a large quantity of dust and fine sand particles away from the ground and carry them over a long distance with significant environmental impacts along the way. In the realm of DSS in Iran country, the people who live in Yazd and Sistan–Baluchestan provinces form a single ecological community due to their geographic proximity and climatic contiguity. The major sources of DSS in the region are believed to be the desert and semidesert areas of the Yazd–Ardakan plain in Yazd province. Both Sistan and Baluchestan are the recipients of this dust. To address the long-range transboundary environmental problem of DSS, a regional cooperation mechanism must be established among the provinces in the region. Yazd–Ardakan plain, with area of about 650,000 ha, is located in the center of Iran, between Yazd and Ardakan cities. The mean annual rainfall is less than 65 mm. Rainfall distribution is a simple modal and more than 70% of it occurs in winter. Plant density varies from 0% to 25%, and Artemisia sieberi is the dominant plant species. The major part of Yazd–Ardakan plain is bare land. According to the recent investigation, more than 20,000-m³ dust with less than 100-μm diameter falls down annually on Yazd city with an area of 7,000 ha. Horizontal visibility is reduced to less than 6 m in stormy days in some parts of Yazd–Ardakan plain. This phenomenon causes car accidents on the main roads of Yazd–Ardakan and can cancel the airplane flights in the stormy days. At present, it is estimated that wind erosion causes more than $6.8 million damages to socioeconomic resources in Yazd plain each year. This paper describes the pattern of occurrence of wind erosion and major contributing factors, summarizes measured rates of wind erosion, outlines the techniques used to mitigate wind erosion hazard, and suggests research priorities. Also, damages of DSS have been estimated and methods for prevention and control are suggested.     

Monitoring of copper level in water and soil samples by using liquid–liquid extraction

A new, simple, sensitive, and selective spectrophotometric method for the determination of copper in water and soil samples has been demonstrated. The method is based on the reaction of Cu(I) with neocuproine (2,9-dimethyl-1, 10-phenanothroline) and extracted with N-phenyl benzimidoylthiourea in chloroform. The value of molar absorptivity of the complex in the term of Cu(I) is 1.45 × 10⁵ L mol^???1 cm^???1 at λ _max 460 nm in chloroform. The detection limit of copper in water and soil is 2 ng mL^???1 and 4 ng g^???1, respectively. The method is free from the interference of the ions commonly found to be associated with the copper determination in water and soil samples. The application of the proposed method has been successfully tested for the determination of copper in different types of water and soil samples.     

CLFUG: A GIS‐scaleable model of pesticide fate in the soil–groundwater system based on clearance and fugacity paradigms

A model of pesticide transport through the soil profile based on clearance and fugacity paradigms is presented, and an example of its application in a GIS environment is shown. A validation of the model at the field plot scale is presented using data obtained at a crop in a semiarid irrigated agricultural basin which was treated with Lindane. The adequacy at the regional scale is tested by inspection of the model predictions and the measured concentrations of the pesticide obtained from a regional phreatimetric net. The clearance concept is used to obtain estimates of the volumes of some environmental phases. These are further used to solve the equations of thermodynamic equilibrium at equal fugacity and obtain concentration estimates. The model closely reproduces the observed percolation trends, and is consistent with the regional pattern of Lindane distribution in groundwater. An application of the model as unitary module for the simulation of non‐point pesticide sources in a raster GIS frame is shown. Its performance (run time, data needed, etc.) is comparable to that of other existing algorithms, and presents some advantages to planners and evaluators of environmental quality in that it incorporates an explicit 2‐D approach and allows the identification of polluted areas downslope with respect to those directly treated with the pesticides. Further, it can be implemented in a variety of GIS and spatial data processors.     

Modeling the plant–soil interaction in presence of heavy metal pollution and acidity variations

On a mathematical interaction model, developed to model metal uptake by plants and the effects on their growth, we introduce a modification which considers also effects on variations of acidity in soil. The model relates the dynamics of the uptake of metals from soil to plants and also variations of uptake according to the acidity level. Two types of relationships are considered: total and available metal content. We suppose simple mathematical assumptions in order to get as simple as possible expressions with the aim of being easily tested in experimental problems. This work introduces modifications to two versions of the model: on the one hand, the expression of the relationship between the metal in soil and the concentration of the metal in plants and, on the other hand, the relationship between the metal in the soil and total amount of the metal in plants. The fine difference of both versions is fundamental at the moment to consider the tolerance and capacity of accumulation of pollutants in the biomass from the soil.     

Microbiological and physical–chemical water quality of the rice fields in Sinos River’s basin, Southern Brazil

In this study, we evaluate spatial and temporal variations of the water’s quality used in rice fields. Every 15 days during the different phases of cultivation of the rice—vegetative, reproductive, and maturity—samples were collected from the main irrigation channel, from the surface water in the field, and from the excess-water drainage channel. The differences in the values of 13 variables were analyzed by the analysis of variance system and by the Principal Component Analysis (PCA) technique. The results demonstrate that the values observed for the presence of total coliforms, heat-tolerant coliforms, and pH were higher in the irrigation water and that the calcium and magnesium components were greater in the drainage water. The PCA results indicate that three groups of variance exist and that these three account for 77 % of the observed variances. The first principal component, (39 % of the variances), includes the variables pH, phosphorus, potassium, carbon, and turbidity; the second (28.1 %), calcium, magnesium, and conductivity; while the third accounts for only 9.9 % of the variation and incorporates the variable biological thermotolerant coliforms. The spatial pattern resulting from the distribution of the sampling locations as regards the first two principal components indicates a difference between the irrigation and drainage waters. The variables of the first and third items (except for the turbidity in the second component) reach higher values in the irrigation water, while the variables associated with the second component have higher values in the drainage water. The information provided is important for the analysis of the influence exercised by plantation management decisions on the microbiological, physical, and chemical quality of the water. The results confirm the ability of paddy rice field to filter out some of the chemicals and coliforms from the irrigation water as it passes through the agro ecosystem.     

Simultaneous derivatization and extraction of nitrophenols in soil and rain samples using modified hollow-fiber liquid-phase microextraction followed by gas chromatography–mass spectrometry

A simple and sensitive method based on a modified hollow-fiber liquid-phase microextraction followed by gas chromatography–mass spectrometry has been successfully developed for the extraction and simultaneous derivatization of some nitrophenols (NPs) in soil and rain samples. Microwave-assisted solvent extraction was used for the extraction of NPs from the soil, while the rain sample was directly applied to the previously mentioned method. Briefly, in this method, the analytes were extracted from aqueous samples into a thin layer of organic solvent (dodecane?+?10 % tri-n-octylphosphine oxide) sustained in the pores of a porous hollow fiber. Then, they were back-extracted using a small volume of organic acceptor solution (25 μl; 10 mg/L N-methyl-N-(trimethylsilyl)trifluoroacetamide, as derivatization reagent, in acetonitrile) that was located inside the lumen of the hollow fiber. Under the optimized extraction conditions, enrichment factors of 255 to 280 and limits of detection of 0.1 to 0.2 μg/L (S/N?=?3) with dynamic linear ranges of 1–100 μg/L were obtained for the analytes. The accuracy of the approach was tested by the relative recovery experiments on spiked samples, with results ranging from 93 to 113 %. The method was shown to be rapid, cost-effective, and potentially interesting for screening purposes.     

Pesticide occurrence and aquatic benchmark exceedances in urban surface waters and sediments in three urban areas of California, USA, 2008–2011

Urban pesticide use has a direct impact on surface water quality. To determine the extent of pesticide contamination, the California Department of Pesticide Regulation initiated a multi-area urban monitoring program in 2008. Water and sediment samples were collected at sites unaffected by agricultural inputs in three areas: Sacramento (SAC), San Francisco Bay (SFB), and Orange County (OC). Samples were analyzed for up to 64 pesticides or degradates. Multiple detections were common; 50 % of the water samples contained five or more pesticides. Statewide, the most frequently detected insecticides in water were bifenthrin, imidacloprid, fipronil, fipronil sulfone, fipronil desulfinyl, carbaryl, and malathion. Bifenthrin was the most common contaminant in sediment samples. Key differences by area: OC had more pesticides detected than SAC or SFB with higher concentrations of fipronil, whereas SAC had higher concentrations of bifenthrin. The most frequently detected herbicides were 2,4-D, triclopyr, dicamba, diuron, and pendimethalin. Key differences by area: OC and SFB had higher concentrations of triclopyr, whereas SAC had higher concentrations of 2,4-D and dicamba. Detection frequency, number of pesticides per sample, and pesticide concentration increased during rainstorm events. In water samples, all of the bifenthrin, malathion, fipronil, permethrin, and λ-cyhalothrin detections, and most of the fipronil sulfone and cyfluthrin detections were above their lowest US EPA aquatic benchmark. Diuron was the only herbicide that was detected above its lowest benchmark. Based on the number of pesticides and exceedances of aquatic benchmarks or the high number of sediment toxicity units, pesticides are abundant in California surface waters.     

Delineation of soil and groundwater contamination using geophysical methods at a waste disposal site in Çanakkale, Turkey

Direct current (DC) resistivity, self potential (SP) and very low frequency electromagnetic (VLF-EM) measurements are carried out to detect the spread of groundwater contamination and to locate possible pathways of leachate plumes, that resulted from an open waste disposal site of Canakkale municipality. There is no proper management of the waste disposal site in which industrial and domestic wastes were improperly dumped. Furthermore, because of the dumpsite is being located at the catchment area borders of a small creek and is being topographically at a high elevation relative to the urban area, the groundwater is expected to be hazardously contaminated. Interpretations of DC resistivity geoelectrical data showed a low resistivity zone (<5 ohm-m), which appears to be a zone, that is fully saturated with leachate from an open dumpsite. The VLF-EM and SP method, support the results of geoelectrical method relating a contaminated zone in the survey area. There is a good correlation between the geophysical investigations and the results of previously collected geochemical and hydrochemical measurements.     

Exploring the multiplicity of soil–human interactions: organic carbon content,agro-forest landscapes and the Italian local communities

Environmental Monitoring and Assessment - Marine ecosystems provide many ecosystem goods and services. However, these ecosystems and the benefits they create for humans are subject to competing...     

Assessment of the redistribution of soil carbon using a new index—a case study in the Haihe River Basin,North China

Soil carbon redistribution is an important process in the terrestrial carbon cycle. This study describes a new index, soil carbon redistribution (SCR) index, that can be used to assess long-term soil carbon redistribution at a large watershed scale. The new index is based on the theoretical preconditions that soil carbon redistribution is mainly controlled by vegetation type, precipitation, topography/slope, and soil carbon concentration. The Haihe River Basin served as an example for this analysis. The SCR index was calculated, and a GIS-based map shows its spatial patterns. The results suggested that soil carbon was usually prone to being carried away from mountainous regions with natural vegetation, while it was prone to deposition in the plain and plateau regions with cultivated vegetation. The methods in the paper offer a tool that can be used to quantify the potential risk where soil carbon is prone to being carried away and deposited in a large watershed.     

Genotoxicity screening of the river Rasina in Serbia using the Allium anaphase–telophase test

Evaluation of the presence of genotoxic substances is especially important in rivers that serve as a source of drinking water. Nine water samples collected along the river Rasina in Serbia were analyzed for potential toxic and genotoxic effects using the Allium anaphase-telophase test. Inhibition of root growth relative to the negative control (synthetic water) was observed in all samples. Analysis of the genotoxic potential, through scoring anaphase and telophase aberrations, showed that in seven of the nine samples the level of aberrations was significantly increased relative to the negative control but was lower than that obtained for the positive control (methyl methanesulfonate). Changes in the relation between spindle and chromosome types of aberrations were found in some samples, indicating differences in the potential genotoxic substances present at the analyzed sites. The data, which were obtained from samples collected at the highest level of river water, warn that during periods of low flow the values could reach genotoxic activity. The Allium anaphase-telophase test can be recommended as an monitoring system, that can serve as the first alert for the presence of genotoxic environmental pollutants.     

Assessing heavy metal pollution in the water level fluctuation zone of China’s Three Gorges Reservoir using geochemical and soil microbial approaches

The water level fluctuation zone (WLFZ) in the Three Gorges Reservoir is located in the intersection of terrestrial and aquatic ecosystems, and assessing heavy metal pollution in the drown zone is critical for ecological remediation and water conservation. In this study, soils were collected in June and September 2009 in natural recovery area and revegetation area of the WLFZ, and geochemical approaches including geoaccumulation index (I _geo) and factor analysis and soil microbial community structure were applied to assess the spatial variability and evaluate the influence of revegetation on metals in the WLFZ. Geochemical approaches demonstrated the moderate pollutant of Cd, the slight pollutant of Hg, and four types of pollutant sources including industrial and domestic wastewater, natural rock weathering, traffic exhaust, and crustal materials in the WLFZ. Our results also demonstrated significantly lower concentrations for elements of As, Cd, Pb, Zn, and Mn in the revegetation area. Moreover, soil microbial community structure failed to monitor the heavy metal pollution in such a relatively clean area. Our results suggest that revegetation plays an important role in controlling heavy metal pollution in the WLFZ of the Three Gorges Reservoir, China.     

Allium cepa L. as a bioindicator to measure cytotoxicity of surface water of the Quatorze River,located in Francisco Beltrão,Paraná, Brazil

Due to an increase in water consumption in the industrial sector and within the Brazilian population, surface water that receives wastewater from industries, domestic sewage, agricultural industries, and sewage treatment stations can pollute water bodies when not properly treated. The water quality has been linked to catchment characteristics and intensity of agricultural activities. Thus, the aim of this study was to monitor the cytotoxic potential of the water of the Quatorze River, located in the town of Francisco Beltrão, Paraná, Brazil, along its route in the rural area, using the root meristematic cells of Allium cepa L. as a bioindicator. The results showed that the water at points 2, 3, and 4 were not cytotoxic because the rates of A. cepa cell division were unaltered. Point 1 had presented a mitotic index that was statistically larger than the negative control, indicating that this water contained substances with mitogenic capacity, as demonstrated by elevated values in chemical oxygen demand (COD) and biochemical oxygen demand (BOD). However, the mitotic index values decreased along the route of the river (point 1 to point 4), possibly indicating a mechanism of self-purification, despite having received other sources of pollution. Thus, the results of this study show that the water of the Quatorze River should undergo periodic environmental monitoring at different times of the year, including cytotoxicity analysis, to evaluate the principal sources of contamination to maintain the quality of the river water and, consequently, to maintain human health and equilibrium of the entire ecosystem.     

GC–ECD analysis of S-metolachlor (Dual Gold) in cotton plant and soil in trial field

The analytical method of S-metolachlor residue and its degradation in cotton and soil in trial field were investigated. S-metolachlor EC (96% w/w) was applied as pre-emergence at dosages of 1,500 and 2,250 ml ha(-1) 3 days after sowing of the cottonseeds in the field. The soil and the plant samples were collected at different intervals and the residues of S-metolachlor were analyzed by GC-ECD. The results showed that the degradation of S-metolachlor in cotton leaves in Beijing and Nanjing coincides with C = 0.1113e(-0.1050t) and C = 0.1177e(-0.1580t), respectively; the half-lives were about 6.6 and 4.4 days. The degradation of S-metolachlor in soil in Beijing and Nanjing coincides with C = 1.0621e(-0.0475) (t), and C = 0.9212e(-0.0548) (t), respectively; the half-lives were about 14.6 and 12.6 days,. At harvest time, the S-metolachlor in cotton seeds and soil samples were detected by GC-ECD and confirmed by GC/MS. The results showed that the residues in cottonseeds were lower than the USA EPA's maximum residue limit of 0.1 mg kg(-1) in cottonseed. It could be considered as safe to human beings and environment.