Applied and Environmental Soil Science
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Open Access journal
ISSN (Print) 1687-7667 - ISSN (Online) 1687-7675
Published by Hindawi [334 journals]
- Influence of Nanolime and Curing Period on Unconfined Compressive Strength
Abstract: This paper presents the improvement of the unconfined compressive strength (UCS) of soil by mixing different percentages of nanolime and 5% lime with soil. The UCS of treated soil increased significantly over curing time with increasing percentage of nanolime. The optimum results were reached at only 0.5% nanolime admixtures which were much higher than 5% lime admixture. This may be due to higher ability of nanolime to flocculate and agglomerate the soil particles compared with the lime. In addition, the lime could fill only the micropores while nanolime could fill the micro- and nanopores as well. The strength gain is inversely proportional to the remolded moisture content and curing period. However, when the content of nanolime used is larger than 0.5%, nanolime particles are not uniformly dispersed. Therefore, a weak area in the form of voids is created, consequently the homogeneous hydrated microstructure cannot be formed, and finally the strength will decrease.
PubDate: Mon, 03 Apr 2017 00:00:00 +000
- Sustainable Management of Calcareous Saline-Sodic Soil in Arid
Environments: The Leaching Process in the Jordan Valley
Abstract: A leaching experiment of calcareous saline-sodic soil was conducted in Jordan Valley and aimed to reduce the soil salinity ≤ 4.0 dS m−1. The quantification of salt removal from the effective root zone was done using three treatment scenarios. Treatment A contained soil amended with gypsum leaching with fresh water (EC = 1.1 dS m−1). Treatments B and C contained nonamended soil, but B was leached with fresh water only while treatment C’s soil was washed with saline agricultural drainage water (EC = 8 dS m−1) at the start of the experiment and continued with fresh water to reach the desired soil salinity. All treatments were able to reduce the soil salinity to the desired level at the end of the experiment; however, there were clear differences in the salt removal efficiencies among the treatments which were attributed to the presence of direct source of calcium ion. The soil amended with gypsum caused a substantial decline in soil salinity and drainage water’s electrical conductivity and drained the water twice as fast as the nonamended soil. It was found that utilizing agricultural drainage water and gypsum as a soil amendment for calcareous saline-sodic soil reclamation can beneficially contribute to sustainable agricultural management in the Jordan Valley.
PubDate: Wed, 01 Mar 2017 08:44:44 +000
- Geotechnologies and Soil Mapping for Delimitation of Management Zones as
an Approach to Precision Viticulture
Abstract: Data of the physical and chemical properties of soils from three vineyards located in Vale dos Vinhedos, Bento Gonçalves, Rio Grande do Sul state, in southern Brazil, were processed. Soil mapping was performed by means of four profiles and the digital elevation model in detailed scale. Then, superficial soils (0–20 cm) were sampled according to a grid pattern. Analysis of variance (ANOVA), kriging, and unsupervised classification methods were applied on physical and chemical data of superficial soils sampled according to grid pattern. This study aimed to compare both methods, the conventional soil mapping and the map produced with superficial soil sampling, about their potential for definition of the management zones, as an approach for precision agriculture. Maps elaborated by conventional soil mapping overlapped partially with the maps derived from superficial sampling, probably due to the specific methodological differences of each case. Anyway, both methods are complementary because of the focus on vertical variability and horizontal variability, respectively. In that sense, slope appears as significant edaphic parameter, due to its control on water circulation in the profile of soil.
PubDate: Thu, 16 Feb 2017 07:18:54 +000
- Spatial Variability and Relationship of Mangrove Soil Organic Matter to
Abstract: Degradation and destruction of mangrove forests in many regions have resulted in the alteration of carbon cycling. Objectives of this study were established to answer the question regarding how much soil organic carbon (SOC) is stored in wetland soils in part of the upper northeastern Gulf of Thailand and to what extent SOC is related to organic matter (OM). A total of 29 soil samples were collected in October 2015. Soil physiochemical analyses followed the standard protocol. Spatial distributions were estimated by a kriging method. Linear regression and coefficient were used to determine the suitable conversion factor for mangrove soils. The results showed that surface soil (0–5 cm) contained higher SOC content as compared to subsurface soil (5–10 cm). Considering a depth of 10 cm, this area had a high potential to sequester carbon with a mean ± standard deviation of %. The spatial variability of OM and SOC revealed that organic matter and carbon decreased with the distance from upstream areas toward the gulf. Based on the assumption that OM is 50% SOC, the conversion factor of 2 is recommended for more accuracy rather than the conventional factor of 1.724.
PubDate: Sun, 29 Jan 2017 07:58:04 +000
- Long and Midterm Effect of Conservation Agriculture on Soil Properties in
Dry Areas of Morocco
Abstract: In Morocco, conservation agriculture, particularly no tillage systems, has become an alternative strategy to mitigate land degradation caused by conventional tillage in semiarid to arid regions. This paper is based on behaviour to tillage treatments of two Vertisols in Morocco. After 11 years of testing, soil organic matter content results showed a significant difference () only at soil surface (0–10 cm) in favour of no tillage and a variation of 30% at this depth. The results obtained after 32 years of testing showed a significant soil profile difference (), up to 40 cm under no tillage compared to conventional tillage, and a variation of 54% at 5–10 cm. For total nitrogen, there was no significant effect between no tillage and conventional tillage at the soil surface after 11 years unlike the result obtained after 32 years. There are no significant differences in bulk density between tillage treatments at soil surface for both sites. The measurement of soil structural stability showed a significant effect () for all three tests and for both sites. This means that no tillage helped Vertisols to resist different climatic constraints, preserving environmental soil quality.
PubDate: Thu, 22 Dec 2016 07:41:42 +000
- Characterization and Classification of Soils of Abobo Area, Western
Abstract: Knowledge of the kinds and properties of soils is critical for making decisions with respect to crop production and other land use types. A field survey and soil morphological description and laboratory analysis were carried out to describe, characterize, and classify the soils of Abobo area, western Ethiopia. Seven representative pedons (A-1 to A-7) were opened and described across the study area. The results revealed variation in morphological, physical, and chemical properties of the soils. The soils are clay loam to clayey in texture with bulk density values ranging from 1.12 to 1.32 g cm−3 and basic infiltration rate varying from slow to moderate (0.4 to 3.3 cm hr−1). They were moderately acidic to neutral in pH (5.5 to 7.1) and had very low to medium organic carbon (OC) (0.27 to 2.98%). Four soil types, Haplic Cambisols, Vertic Luvisols, Mollic Leptosols, and Mollic Vertisols, were identified in the area based on World Reference Base. Generally, the properties of the soils differed along the transect indicating their variation in productive potential and management requirements for specific agricultural use.
PubDate: Mon, 19 Dec 2016 09:39:49 +000
- Assessing Land Suitability for Rainwater Harvesting Using Geospatial
Techniques: A Case Study of Njoro Catchment, Kenya
Abstract: Water demand increases as population increases leading to overexploitation of water resource. Consequently, there is need for improved water resources management complemented with rain water harvesting within the catchments. This study sought to assess land suitability for surface runoff harvesting using geospatial techniques. Land use/land cover maps of the area were derived from Landsat image. Land use and soils data were used in generating curve number map of the catchment. Lineaments greatly affect the storage depending on whether runoff is for surface storage or ground water recharge purposes. As a result, ArcGIS was used in delineating the lineaments from Digital Elevation Model (DEM) of the catchment. Further, using weighted overlay the catchment was grouped into categories of restricted, not suitable, moderately suitable, suitable, or highly suitable. The study found that forest, agriculture, and built-up areas occupied about 39.42%, 36.32%, and 1.35% of catchment area, respectively. A large part of catchment was found to have curve number range of 82–89. About 50% of the catchment was found to fall within suitable and highly suitable categories. This implied that a great potential exists for rain water harvesting within the catchment.
PubDate: Thu, 08 Dec 2016 15:12:45 +000
- Potential of Using Nanocarbons to Stabilize Weak Soils
Abstract: Soil stabilization, using a variety of stabilizers, is a common method used by engineers and designers to enhance the properties of soil. The use of nanomaterials for soil stabilization is one of the most active research areas that also encompass a number of disciplines, including civil engineering and construction materials. Soils improved by nanomaterials could provide a novel, smart, and eco- and environment-friendly construction material for sustainability. In this case, carbon nanomaterials (CNMs) have become candidates for numerous applications in civil engineering. The main objective of this paper is to explore improvements in the physical properties of UKM residual soil using small amounts (0.05, 0.075, 0.1, and 0.2%) of nanocarbons, that is, carbon nanotube (multiwall carbon nanotube (MWCNTs)) and carbon nanofibers (CNFs). The parameters investigated in this study include Atterberg’s limits, optimum water content, maximum dry density, specific gravity, pH, and hydraulic conductivity. Nanocarbons increased the pH values from 3.93 to 4.16. Furthermore, the hydraulic conductivity values of the stabilized fine-grained soil samples containing MWCNTs decreased from m/s to m/s and, in the reinforcement sample by CNFs, the hydraulic conductivity value decreased to m/s. Small amount of nanocarbons (MWCNTs and CNFs) decreased the optimum moisture content, increased maximum dry density, reduced the plasticity index, and also had a significant effect on its hydraulic conductivity.
PubDate: Thu, 17 Nov 2016 11:20:36 +000
- Vertical Phosphorus Migration in a Biosolids-Amended Sandy Loam Soil in
Laboratory Settings: Concentrations in Soils and Leachates
Abstract: The impacts of biosolids land application on soil phosphorus and subsequent vertical migration to tile drainage were assessed in a laboratory setup. Soil, representing typical “nonresponse” Ontario soil as specified by Ontario Ministry of Agriculture, Food, and Rural Affairs (OMAFRA), was amended with anaerobically digested biosolids at a rate of 8 Mg ha−1 (dry weight). Over five months, these amended soil samples from two different depths were sequentially fractionated to determine various inorganic and organic phosphorus pools in order to evaluate phosphorus vertical migration within a soil profile. Soil leachate was analyzed for soluble reactive phosphorus. The results indicated that biosolids application did not significantly affect phosphorus concentrations in soil and did not cause phosphorus vertical migration. The concentrations of soluble reactive phosphorus also were not significantly affected by biosolids.
PubDate: Wed, 16 Nov 2016 11:13:04 +000
- Composition of Trace Metals in Dust Samples Collected from Selected High
Schools in Pretoria, South Africa
Abstract: Potential health risks associated with trace metal pollution have necessitated the importance of monitoring their levels in the environment. The present study investigated the concentrations and compositions of trace metals in dust samples collected from classrooms and playing ground from the selected high schools In Pretoria. Schools were selected from Pretoria based on factors such as proximity to high traffic ways, industrial areas, and residential areas. Thirty-two dust samples were collected from inside and outside the classrooms, where learners often stay during recess period. The dust samples were analysed for trace metal concentrations using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The composition of the elements showed that the concentrations of Zn were more than all other elements except from one of the schools. There were significant differences in the concentrations of trace metals from the schools (). Regular cleaning, proximity to busy road, and well maintained gardens seem to have positive effects on the concentrations of trace metals recorded from the classrooms dust. The result further revealed a positive correlation for elements such as Pb, Cu, Zn, Mn, and Sb, indicating that the dust might have a common source.
PubDate: Wed, 16 Nov 2016 09:11:32 +000
- Trace Metal Contamination Characteristics and Health Risks Assessment of
Abstract: The purpose of this study was to investigate and quantify trace metal concentrations in Commelina africana L. and psammitic sandflats from an intertidal coastal ecosystem in Niger Delta, Nigeria, and to evaluate their spatial distribution, degree of contamination, and source apportionment. The environmental risks associated with soil contamination were elaborately assessed using potential ecological risk index, sediment quality guidelines, and enrichment relative to background levels. The mean concentrations of Cd, Cr, Ni, Pb, and Zn in sandflat soil samples are , , , , and mg/kg, respectively. Metal levels indicate strong variability with sampling sites. The order of trace metal concentrations in the Commelina africana L. samples is . The concentrations varied with the sample locations; and the levels of Pb (0.05 to 0.08 mg/kg) at all locations are found to be significantly below permissible level of 0.3 mg/kg. Potential sources of metal loadings may be associated with localised or diffused anthropogenic activities. The average carcinogenic risks are below threshold values, and the sandflat soils are not considered to pose significant health effects to children and adult males and females. However, the carcinogenicity and noncarcinogenicity risks ranking decrease following the order . Comparatively, the hazard quotient and hazard index indicate that the psammitic sandflats might pose a health risk to children in future.
PubDate: Tue, 18 Oct 2016 14:28:10 +000
- Manganese Fractionation in Soils after Application of Municipal Solid
Wastes Compost in Two Consecutive Years
Abstract: In order to study the effect of Tehran municipal solid wastes compost on manganese accumulation in soil and to determine its concentration in any readily available plant forms (exchangeable and carbonates-bonded), Mn-oxides bonded fraction, organic matter bonded fraction, and residual fraction in a calcareous soil, a factorial experiment based on completely randomized block design (RCBD) was conducted in research field of Shahed university at different levels of municipal solid wastes compost (0, 15, 30, and 60 ton/ha) as first factor and application times (one- or two-year compost application) as second factor in three replications. Results showed that, by increasing compost level, total Mn concentration, DTPA-extractable concentration, and amounts existing in all five fractions were increased, so lowest and highest amounts of Mn were observed in control and 60 ton/ha compost application. Based on results from Mn fractionation using Tessier consecutive extraction method, Mn fractions in all samples were in the following order: residual > Fe-Mn oxides > carbonates-bonded > organic matter-bonded ≫ exchangeable fractions in which residual fraction (RE) at first and second year was dominant rather than other fractions by 34.28–43.04 and 34.28–49.48 percent, respectively. Mn concentration in Fe-Mn oxides-bonded fraction at both years was considerable. Mn amounts in Fe-Mn oxides- bonded, application times were decreased.
PubDate: Mon, 10 Oct 2016 12:33:49 +000
- Potential for Lead Release from Lead-Immobilized Animal Manure Compost in
Rhizosphere Soil of Shooting Range
Abstract: This study aimed to clarify the magnitude of lead release from lead-sorbed animal manure compost (AMC) in rhizosphere soil compared with nonplanted soil of shooting range. The presence of buckwheat caused reduction in rhizosphere soil pH and enhancement in the level of water-soluble organic carbon compared with those of nonplanted soil. In addition, the presence of buckwheat altered the lead phases and increased the relative amount of the soluble exchangeable fraction, resulting in increase in the CaCl2-soluble lead level. In contrast, the presence of Guinea grass did not change the lead bioavailability or phases compared with nonplanted soil. Lead release tests in solution showed that between solution pH 5 and solution pH 7 the amount of lead released from the compost was higher in the rhizosphere soil of buckwheat than in nonplanted soil, whereas there was no significant difference between the rhizosphere soil of Guinea grass and nonplanted soil. These results suggest that the increase in the quantity of exchangeable lead resulting from the rhizosphere effect induces lead immobilized by the AMC to be remobilized. Therefore, AMC should be applied to soils that contain plants that are unable to alter the lead phases in the shooting range soil. Efforts should be particularly made to ensure that lead cannot be transformed to the exchangeable phase.
PubDate: Thu, 08 Sep 2016 07:25:43 +000
- Variability of Soil Micronutrients Concentration along the Slopes of Mount
Abstract: Soil micronutrients are important elements for plant growth despite being required in small quantities. Deficiency of micronutrients can result in severe crop failure while excess levels can lead to health hazards; therefore, investigating their status in agricultural land is crucial. Fifty plots were established along an altitudinal gradient from 680 to 1696 m a.s.l. on the slopes of Mount Kilimanjaro, Tanzania. Soils were sampled at the top- (0–20 cm) and subsoils (21–50 cm) in four locations within each plot. Fourier Transform Mid-Infrared (FT-MIR) spectroscopy and wet chemistry were used for soil analysis. Results indicated that the mean concentrations of the micronutrients in the topsoil were Fe (mgkg−1), Mn (mgkg−1), Zn ( mgkg−1), B (mgkg−1), and Cu (mgkg−1). Variations of the micronutrients were not statistically different by elevation (df = 41, ) and by soil depth (df = 49, ). Correlations among micronutrients were significant for Fe versus Mn (, ), B versus Zn (, ), B versus Cu (, ), and Cu versus Zn (, ). The correlated micronutrients implied that they were affected by similar factors. Soil pH correlated positively with B, Fe, and Mn and negatively with Cu and Zn, hence probably influencing their availability. Therefore, the need for sustaining micronutrient at sufficient levels is crucial. Management interventions may include moderating soil pH by reducing acidity through liming in the higher elevations and incorporation of organic matter in the lowlands.
PubDate: Thu, 04 Aug 2016 09:57:29 +000
- Assessing the Suitability and Availability of Land for Agriculture in
Tuban Regency, East Java, Indonesia
Abstract: Indonesian food production depends highly on Java Island, which holds the most fertile soils in the country but had limited area. The objective of the research was to analyse the availability of suitable land for agriculture in Tuban Regency, an agricultural regency in Java Island. Land suitability was evaluated with spatial multicriteria analysis, integrating soil order, land capability, elevation, slope, slope direction, land use/land cover, accessibility, and climate. Land availability was analysed, integrating the forest area status designation and the spatial pattern of regional official land use plan. The results indicated that suitable land for agriculture corresponds to 91% of the total study area, confirming the high soil fertility. Analysis of land availability then indicated that 18% of the area was both suitable and available for agriculture. Considering the actual land utilization, the future development of agriculture in the region has less than 7% of the land area left for agricultural expansion. The overall results showed the importance of looking for land allocated for agriculture outside Java Island to anticipate the need for food of a country with a high population growth rate and also developing planning for food production.
PubDate: Wed, 03 Aug 2016 12:17:28 +000
- Soil Pollution Prevention and Remediation
PubDate: Sun, 17 Jul 2016 06:38:28 +000
- Integrated Approaches to Soil Contamination Monitoring
PubDate: Mon, 27 Jun 2016 11:35:10 +000
- Chemical and Physical Characteristics in Uncultivated Soils with Different
Lithology in Semiarid Mediterranean Clima
Abstract: The aim of this study is to identify the chemical and physical characteristics in uncultivated soils derived from different parent materials under semiarid Mediterranean climatic conditions which favoured the formation of fragile soils. The current work is of great interest in the agriculture and environmental stakeholders for providing a “benchmark” of undisturbed soil quality regarding organic content and nutrients availability. Principal Component Analysis (PCA) was used as the primary tool to demonstrate the soil quality stage, regarding nutrient availability. The statistical analysis revealed that one of the major physicochemical characteristics such as cation exchange capacity (CEC) is controlled exclusively from mineralogy and not from organic matter. Mineralogy and bulk chemical analysis is directly related to soil parent material lithology. The availability of inorganic nutrients (macro- and micronutrients) is low and relatively identical to most of the soils. PCA shows the unusual correlation of K+ with not only illite content but also the OM in soils. The development of soils which are already of low quality in respect of organic content and nutrients is evident in Crete in most of the 54 samples investigated.
PubDate: Mon, 20 Jun 2016 10:58:46 +000
- Previous Crop and Cultivar Effects on Methane Emissions from Drill-Seeded,
Delayed-Flood Rice Grown on a Clay Soil
Abstract: Due to anaerobic conditions that develop in soils under flooded-rice (Oryza sativa L.) production, along with the global extent of rice production, it is estimated that rice cultivation is responsible for 11% of global anthropogenic methane (CH4) emissions. In order to adequately estimate CH4 emissions, it is important to include data representing the range of environmental, climatic, and cultural factors occurring in rice production, particularly from Arkansas, the leading rice-producing state in the US, and from clay soils. The objective of this study was to determine the effects of previous crop (i.e., rice or soybean (Glycine max L.)) and cultivar (i.e., Cheniere (pure-line, semidwarf), CLXL745 (hybrid), and Taggart (pure-line, standard-stature)) on CH4 fluxes and emissions from rice grown on a Sharkey clay (very-fine, smectitic, thermic Chromic Epiaquerts) in eastern Arkansas. Rice following rice as a previous crop generally had greater () fluxes than rice following soybean, resulting in growing season emissions () of 19.6 and 7.0 kg CH4-C ha−1, respectively. The resulting emissions from CLXL745 (10.2 kg CH4-C ha−1) were less () than those from Cheniere or Taggart (15.5 and 14.2 kg CH4-C ha−1, resp.), which did not differ. Results of this study indicate that common Arkansas practices, such as growing rice in rotation with soybean and planting hybrid cultivars, may result in reduced CH4 emissions relative to continuous rice rotations and pure-line cultivars, respectively.
PubDate: Sun, 05 Jun 2016 08:44:49 +000
- Integrated Nanozero Valent Iron and Biosurfactant-Aided Remediation of
Abstract: Polychlorobiphenyls (PCBs) have been identified as environmental hazards for years. Due to historical issues, a considerable amount of PCBs was released deep underground in Canada. In this research, a nanoscale zero valent iron- (nZVI-) aided dechlorination followed by biosurfactant enhanced soil washing method was developed to remove PCBs from soil. During nZVI-aided dechlorination, the effects of nZVI dosage, initial pH level, and temperature were evaluated, respectively. Five levels of nZVI dosage and two levels of initial pH were experimented to evaluate the PCB dechlorination rate. Additionally, the temperature changes could positively influence the dechlorination process. In soil washing, the presence of nanoiron particles played a key role in PCB removal. The crude biosurfactant was produced using a bacterial stain isolated from the Atlantic Ocean and was applied for soil washing. The study has led to a promising technology for PCB-contaminated soil remediation.
PubDate: Thu, 19 May 2016 16:33:22 +000
- Diurnal Variation of Soil Heat Flux at an Antarctic Local Area during
Abstract: Soil heat flux () is one term in the energy balance equation, and it can be particularly important in regions with arid, bare, or thinly vegetated soil surfaces. However, in remote areas such as the Antarctic, this measurement is not routinely performed. The analysis of observational data collected by the ETA Project at the Brazilian Antarctic Station from December 2013 to March 2014 showed that, for the total daily energy flux, the surface soil flux heats the deeper soil layers during December and January and acts as a heat source to the outer soil layers during February and March. With regard to daytime energy flux, acts as a source of heat to the deeper layers. During the night-time, the soil is a heat source to the shallower soil layers and represents at least 29% of the net night-time radiation. A relatively simple method—the objective hysteresis method (OHM)—was successfully applied to determine the surface soil heat flux using net radiation observations. A priori, the OHM coefficients obtained in this study may only be used for short-time parameterizations and for filling data gaps at this specific site.
PubDate: Wed, 18 May 2016 07:02:33 +000
- Nutrients Release from a Novel Gel-Based Slow/Controlled Release
Abstract: A novel gel-based slow/controlled release fertilizer (G-CRF) was developed, which was produced by combining various natural, seminatural, and/or synthetic organic macromolecule materials and natural inorganic mineral with conventional NPK fertilizers. Its nutrient release characteristics were studied to compare with conventional fertilizers through the soil column leaching method. The influences of soil factors, including temperature, pH, water, and nutrient contents in the G-CRF on nutrient release, were also investigated through soil-water incubation method. These results indicated that the G-CRF had better effect on controlling release of N, P, and K nutrients, and the effect was more efficient when soil-water content was lower than 45% (w/w), temperature was below 35°C, and soil pH was in the range from weak acid to neutral. In addition, considering the effect of controlling nutrient release and cost of the materials in the G-CRF, it is recommended that the most feasible NPK nutrient contents in the G-CRF ranged from 30 to 35%.
PubDate: Tue, 17 May 2016 06:40:08 +000
- Phytoremediation of Gold Mine Tailings Amended with Iron-Coated and
Uncoated Rice Husk Ash by Vetiver Grass (Vetiveria zizanioides (Linn.)
Abstract: This study was undertaken to determine the effects of rice husk ash (RHA) and iron-coated rice husk ash (Fe-RHA) on phytoavailability of As, Cd, Cr, Cu, Mn, Pb, and Zn to vetiver grass grown in gold mine tailings amended with either RHA or Fe-RHA at 0%, 5%, 10%, and 20% (w/w). The results showed that the RHA amended tailings recorded higher concentration of As in the shoot and the root and higher concentration of Cr and Mn in the root compared to the untreated tailings which was used as a control. The biological accumulation coefficient (BAC) and bioconcentration factor (BCF) values of the vetiver grass for As and Zn increased with RHA application rate but the biological transfer coefficient (BTC) values of As and Zn were decreased. In Fe-RHA amended samples, As concentration in the shoot and root concentrations of Cd and Zn were significantly higher compared to the control. The Fe-RHA treated samples had lower BAC and BTC values for As and Zn than the control. However, the BCF values for those elements were higher than the control. The concentration of Pb was not detected in any of the samples.
PubDate: Tue, 10 May 2016 06:56:12 +000
- Dissolution of Metals from Biosolid-Treated Soils by Organic Acid Mixtures
Abstract: Results for the solubilization of metals from biosolid- (BSL-) treated soils by simulated organic acid-based synthetic root exudates (OA mixtures) of differing composition and concentrations are presented. This study used two BSL-treated Romona soils and a BSL-free Romona soil control that were collected from experimental plots of a long-term BSL land application experiment. Results indicate that the solubility of metals in a BSL-treated soil with 0.01 and 0.1 M OA mixtures was significantly higher than that of 0.001 M concentrations. Differences in composition of OAs caused by BSL treatment and the length of growing periods did not affect the solubility of metals. There were no significant differences in organic composition and metals extracted for plants grown at 2, 4, 8, 12, and 16 weeks. The amount of metals extracted tended to decrease with the increase of the pH. Results of metal dissolution kinetics indicate two-stage metal dissolution. A rapid dissolution of metals occurred in the first 15 minutes. For Cd, Cu, Ni, and Zn, approximately 60–70% of the metals were released in the first 15 minutes while the initial releases for Cr and Pb were approximately 30% of the total. It was then followed by a slow but steady release of additional metals over 48 hours.
PubDate: Thu, 14 Apr 2016 06:12:05 +000
- Oil and Gas Production Wastewater: Soil Contamination and Pollution
Abstract: During oil and natural gas production, so-called “produced water” comprises the largest byproduct stream. In addition, many oil and gas operations are augmented via injection of hydraulic fracturing (HF) fluids into the formation. Both produced water and HF fluids may contain hundreds of individual chemicals, some known to be detrimental to public health and the environment. Oil and gas production wastewater may serve a range of beneficial purposes, particularly in arid regions, if managed correctly. Numerous treatment technologies have been developed that allow for injection, discharge to the land surface, or beneficial reuse. Although many papers have addressed the effects of oil and gas production wastewater (OGPW) on groundwater and surface water quality, significantly less information is available on the effects of these fluids on the soil resource. This review paper compiles fundamental information on numerous chemicals used and produced during oil and gas development and their effects on the soil environment. Additionally, pollution prevention technologies relating to OGPW are presented. An understanding of the effects of OGPW on soil chemical, physical, and biological properties can provide a foundation for effective remediation of OGPW-affected soils; additionally, sustainable reuse of oil and gas water for irrigation and industrial purposes may be enhanced.
PubDate: Sun, 20 Mar 2016 07:59:43 +000
- Long-Term Dynamics of Urban Soil Pollution with Heavy Metals in Moscow
Abstract: Results of 21-year-long (1989–2010) observations of the concentrations and the spatial distribution patterns of nine heavy metals (HMs) in topsoils of the Eastern district of Moscow are presented. The quantitative parameters of soil pollution include the annual increase rates of HM concentrations in several land-use zones. The maps of geochemical anomalies were compiled using the data collected in 1989, 2005, and 2010. The growth of the total volume of industrial and vehicles’ emissions between 1989 and 2005 caused significant deposition of Pb, Zn, Cu, and Cd. The additional input of Cd to the soils is attributed to the application of sewage sludge as fertilizers. The relative increment of concentrations was the highest for Pb, Co, Cu, Ni, and Cr. In 2005–2010, the relative annual increment rate was the highest for Cr, Cd, Co, and Ni, and it increased by an order of magnitude as compared to the previous period. By contrast, Pb and Cu concentrations decreased owing to the soil reclamation, the exclusion of leaded gasoline as a fuel for vehicles and closing some hazardous enterprises. Joint analysis of snow and soil geochemical maps allows identification of the zones of actual, permanent, and relict pollution.
PubDate: Sun, 06 Mar 2016 07:20:49 +000
- Using Cosmic-Ray Neutron Probes to Monitor Landscape Scale Soil Water
Content in Mixed Land Use Agricultural Systems
Abstract: With an ever-increasing demand for natural resources and the societal need to understand and predict natural disasters, soil water content (SWC) observations remain a critical variable to monitor in order to optimally allocate resources, establish early warning systems, and improve weather forecasts. However, routine agricultural production practices of soil cultivation, planting, and harvest make the operation and maintenance of direct contact point sensors for long-term monitoring challenging. In this work, we explore the use of the newly established Cosmic-Ray Neutron Probe (CRNP) and method to monitor landscape average SWC in a mixed agricultural land use system in northeast Austria. The calibrated CRNP landscape SWC values compare well against an independent in situ SWC probe network (MAE = 0.0286 m3/m3) given the challenge of continuous in situ monitoring from probes across a heterogeneous agricultural landscape. The ability of the CRNP to provide real-time and accurate landscape SWC measurements makes it an ideal method for establishing long-term monitoring sites in agricultural ecosystems to aid in agricultural water and nutrient management decisions at the small tract of land scale as well as aiding in management decisions at larger scales.
PubDate: Mon, 29 Feb 2016 09:24:10 +000
- Combining Geoelectrical Measurements and CO2 Analyses to Monitor the
Enhanced Bioremediation of Hydrocarbon-Contaminated Soils: A Field
Abstract: Hydrocarbon-contaminated aquifers can be successfully remediated through enhanced biodegradation. However, in situ monitoring of the treatment by piezometers is expensive and invasive and might be insufficient as the information provided is restricted to vertical profiles at discrete locations. An alternative method was tested in order to improve the robustness of the monitoring. Geophysical methods, electrical resistivity (ER) and induced polarization (IP), were combined with gas analyses, CO2 concentration, and its carbon isotopic ratio, to develop a less invasive methodology for monitoring enhanced biodegradation of hydrocarbons. The field implementation of this monitoring methodology, which lasted from February 2014 until June 2015, was carried out at a BTEX-polluted site under aerobic biotreatment. Geophysical monitoring shows a more conductive and chargeable area which corresponds to the contaminated zone. In this area, high CO2 emissions have been measured with an isotopic signature demonstrating that the main source of CO2 on this site is the biodegradation of hydrocarbon fuels. Besides, the evolution of geochemical and geophysical data over a year seems to show the seasonal variation of bacterial activity. Combining geophysics with gas analyses is thus promising to provide a new methodology for in situ monitoring.
PubDate: Wed, 17 Feb 2016 11:35:56 +000
- Transport Processes in Porous Media by Self-Potential Method
Abstract: A controlled diffusion/infiltration column experimental activity was carried out with the aim of monitoring the leakage of a salty water plume by time-lapse self-potential (SP) measurements. In particular, three tracer tests with different NaCl concentrations (6.00, 1.00, and 0.25 g L−1) were performed and all the measured SP signals showed a sharp reduction corresponding to the arrival of saline front with negative electrical potential values (− mV, − mV, and − mV) which decrease with increasing volume of tracer introduced into the column. Then, measured self-potential values were converted into salt concentration ones by the Planck-Henderson equation and sand diffusion and longitudinal dispersivity () values were estimated by modelling the transport equations in the COMSOL Multiphysics environment. Finally, the results show that measured and estimated NaCl concentrations are well correlated.
PubDate: Tue, 26 Jan 2016 14:16:38 +000
- A Rationale for Pollutograph Evaluation in Ungauged Areas, Using Daily
Rainfall Patterns: Case Studies of the Apulian Region in Southern Italy
Abstract: In the context of the implementation of sustainable water treatment technologies for soil pollution prevention, a methodology that try to overcome the lack of runoff quality data in Puglia (Southern Italy) is firstly tackled in this paper. It provides a tool to obtain total suspended solid (TSS) pollutographs in areas without availability of monitoring campaigns. The proposed procedure is based on the relationship between rainfall characteristics and pollutant wash-off. In particular, starting from the evaluation of the observed regional rainfall patterns by using a rainfall generator model, the storm water management model (SWMM) was applied on five case studies located in different climatic subareas. The quantity SWMM parameters were evaluated starting from the drainage network and catchments characteristics, while the quality parameters were obtained from results of a monitoring campaign conducted for quality model calibration and validation with reference to the pollutograph’s shape and the peak-time. The research yields a procedure useful to evaluate the first flush phenomenon in ungauged sites and, in particular, it provides interesting information for designing efficient and sustainable drainage systems for first flush treatment and diffuse pollution treatment.
PubDate: Sun, 24 Jan 2016 08:40:09 +000