Effect of organic and inorganic phosphorus fertilizers on phosphorus availability and its leaching over incubation time

Environmental Science and Pollution Research - The use of organic and inorganic phosphorus (P) fertilizers in agricultural soils is very common, and few studies have been conducted to...     

Laboratory-based assessment on similarities between dynamic behavior of MSW and clay

Journal of Material Cycles and Waste Management - The dynamic response of landfills under seismic loads is greatly dependent on stress–strain cyclic characteristics of municipal solid waste...     

Trace element contaminants in mineral fertilizers used in Iran

The application of mineral fertilizers which have contaminants of trace elements may impose concern regarding the entry and toxic accumulation of these elements in agro-ecosystems. In this study, 57 mineral fertilizers (nitrogen, potassium, phosphate, and compound fertilizers) distributed in Iran were analyzed for their contents of Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn, and Fe. The results revealed that the contents of these trace elements varied considerably depending on the type of the element and the fertilizer. Among these elements, Fe displayed the highest average content, whereas Cd showed the lowest. Generally, the trace element contents in P-containing fertilizers were higher than those in nitrogen and potassium fertilizers. The mean values of trace elements (mg kg^?1) in P-containing fertilizers were 4.0 (Cd), 5.5 (Co), 35.7 (Cr), 24.4 (Cu), 272 (Mn), 14.3 (Ni), 6.0 (Pb), 226 (Zn), and 2532 (Fe). Comparing trace element contents to limit values set by the German Fertilizer Ordinance showed that the mean contents of potentially toxic trace elements, such as Cd and Pb, were lower than their limit values in all groups of fertilizers. On the other hand, while a number of fertilizers contained a high content of some essential trace elements, particularly Fe, they were not labeled as such.     

Colloid-Associated Groundwater Contaminant Transport in Homogeneous Saturated Porous Media: Mathematical and Numerical Modeling

During the past two decades, significant efforts have been made to study contaminant transport in the presence of colloids. Several researchers reported that colloidal particles could enhance the migration of contaminants in groundwater by reducing retardation factor. When the colloidal particles are present in the aquifer, the subsurface system can be considered as a three-phase system with two solid phases and an aqueous phase. The interaction between contaminants, colloids, and solid matrix should be considered in assessing the fate and transport of the contaminant in the groundwater flow system. In this study, a one-dimensional numerical model is developed by employing a fully implicit finite difference method. This model is based on mass balance equations and mass partition mechanisms between the carriers and solid matrix, as well as between the carriers and contaminants in a saturated homogeneous porous medium. This phenomenon is presented by two approaches: equilibrium approach and fully kinetic first-order approach. The formulation of the model can be simplified by employing equilibrium partitioning of particles. However, contaminant transport can be predicted more accurately in realistic situations by kinetic modeling. To test the sensitivity of the model, the effect of the various chemical and physical coefficients on the migration of contaminant was investigated. The results of numerical modeling matched favorably with experimental data reported in the literature.     

The influence of dilute sulfuric acid pretreatment on biogas production from wheat plant

Dilute sulfuric acid pretreatment was used to improve the biomethane production from wheat plant (WP) via mesophilic anaerobic digestion. The pretreatments were performed at 121°C for different time durations of 10, 30, 60, and 120 min. The maximum methane yield of 302.4 mL/g volatile solids (VS) was obtained after the pretreatment for 120 min, which was 15.5% higher than that of the untreated WP. The highest amounts of lignin removal (15.2%) and xylan degradation (91.5%) were also achieved after this pretreatment. The pretreatment for 60 min enhanced the methane yield by 8.9%, while the pretreatments for 10 and 30 min had no positive effects on the methane yield. All of the pretreatments significantly removed the hemicelluloses. Moreover, the qualitative analysis of the untreated and pretreated WP structure showed significant reduction in the crystallinity index accompanied by the destruction of surface layers of WP structure after pretreatment.     

Nitrates leaching from agricultural land in Hamadan, western Iran

Nitrogen (N) is vital for plant and microbial growth and rather large amounts are required by most arable and horticulture plants. High nitrate (NO₃⁻) levels of water supplies have been attributed to leaching from the soil and into water systems. In the arid and semi-arid regions, irrigation water carries NO₃⁻ into groundwater. This study was conducted to investigate NO₃⁻ pollution of groundwater in Hamadan, western Iran. The water samples were mostly taken from domestic and community wells. In this area, the drinking water supply comes mainly from groundwater sources. Nitrate concentrations in the well samples varied from 3 to 252 with the average of 49 mg l⁻¹. Results showed that of 311 wells, 196 (63%) had levels less than 50 mg l⁻¹ and 115 (37%) had levels in excess of the 50 mg l⁻¹ NO₃⁻. Agriculture is the dominant land use in the area and application of N fertilizers clearly has an impact on groundwater. If agricultural losses remain stable, it could be expected that the concentration of NO₃⁻ in groundwater will reach or exceed the international recommendations for drinking water (50 mg l⁻¹) in the future. Irrigation with high NO₃⁻ groundwater can minimise the requirement for N fertilizers. To maintain yield increase and minimise NO₃⁻ pollution of the groundwater, best management practices, for N fertilizer use should be applied and excessive fertilizer application prevented.     

Life‐Cycle Assessment of Construction in a Developing Country

The construction industry plays a great role in a country's or an area's economy. Construction activities also have significant and increasing effects on the environment. Life‐cycle assessment (LCA) is one of the environmental management techniques that can be used to evaluate the environmental burdens of construction. The authors of this study applied the LCA approach and SimaPro 7.1 software within the framework of the International Organization of Standardization's (ISO) 14040 series of standards and analyzed the global warming potential (GWP) and acidification potential (AP) of the materials acquisition and construction phases of the Parand residential apartment complex located in the southwest part of Tehran province, Iran.     

A systematic indoor air quality audit approach for public buildings

Good indoor air quality (IAQ) in buildings provides a comfortable and healthy environment for the occupants to work, learn, study, etc. Therefore, it is important to ascertain the IAQ status in the buildings. This study is aimed to establish and demonstrate the comprehensive IAQ audit approach for public buildings, based on Portugal national laws. Four public buildings in Portugal are used to demonstrate the IAQ audit application. The systematic approach involves the measurement of physical parameters (temperature, relative humidity, and concentration of the suspended particulate matter), monitoring of the concentrations of selected chemical indicators [carbon dioxide (CO₂), carbon monoxide, formaldehyde, ozone, and total volatile organic compounds], and the measurements of biological indicators (bacteria and fungi). In addition, air exchange rates are measured by the concentration decay method using metabolic CO₂ as the tracer gas. The comprehensive audits indicated some situations of common IAQ problems in buildings, namely: (1) insufficient ventilation rate, (2) too high particle concentration; and (3) poor filtration effectiveness and hygienic conditions in most of the air handling units. Accordingly, a set of recommendations for the improvement of IAQ conditions were advised to the building owner/managers.