Empirical gas emission and oxidation measurement at cover soil of dumping site: example from Malaysia

Methane (CH₄) is one of the most relevant greenhouse gases and it has a global warming potential 25 times greater than that of carbon dioxide (CO₂), risking human health and the environment. Microbial CH₄ oxidation in landfill cover soils may constitute a means of controlling CH₄ emissions. The study was intended to quantify CH₄ and CO₂ emissions rates at the Sungai Sedu open dumping landfill during the dry season, characterize their spatial and temporal variations, and measure the CH₄ oxidation associated with the landfill cover soil using a homemade static flux chamber. Concentrations of the gases were analyzed by a Micro-GC CP-4900. Two methods, kriging values and inverse distance weighting (IDW), were found almost identical. The findings of the proposed method show that the ratio of CH₄ to CO₂ emissions was 25.4 %, indicating higher CO₂ emissions than CH₄ emissions. Also, the average CH₄ oxidation in the landfill cover soil was 52.5 %. The CH₄ and CO₂ emissions did not show fixed-pattern temporal variation based on daytime measurements. Statistically, a negative relationship was found between CH₄ emissions and oxidation (R ²?=?0.46). It can be concluded that the variation in the CH₄ oxidation was mainly attributed to the properties of the landfill cover soil.     

Heavy metal bioaccumulation and risk assessment for wild and farmed beluga sturgeon caviar

Because of over-exploitation of sturgeon for caviar production, they have been listed worldwide in annex II of the Convention on International Trade in Endangered Species regulations; so caviar production using aquaculture is increasingly seen as a feasible way to reduce overfishing. The accumulation of the nonessential metals As, Ba, Cd, Hg, Pb, and Sn was determined in the caviar of farmed and wild Beluga sturgeon (Huso huso). The levels of As in both and Cd in wild samples were less than 0.01 mg kg^?1 wet weight, and the comparison for all of the metals studied did not show large fluctuations in metal concentrations between farmed and wild caviar samples. The average for each toxic metal was below the permissible limits proposed by the UK’s Ministry of Agriculture, Fisheries and Foods (2000). The maximum allowable daily consumption rate of caviar was calculated; however, the health risks from caviar consumption are uncertain because the amount of caviar consumed by heavy users is not known.     

The effectiveness of digital soil mapping to predict soil properties over low-relief areas

This study investigates the ability of different digital soil mapping (DSM) approaches to predict some of physical and chemical topsoil properties in the Shahrekord plain of Chaharmahal-Va-Bakhtiari province, Iran. According to a semi-detailed soil survey, 120 soil samples were collected from 0 to 30 cm depth with approximate distance of 750 m. Particle size distribution, coarse fragments (CFs), electrical conductivity (EC), pH, organic carbon (OC), and calcium carbonate equivalent (CCE) were determined. Four machine learning techniques, namely, artificial neural networks (ANNs), boosted regression tree (BRT), generalized linear model (GLM), and multiple linear regression (MLR), were used to identify the relationship between soil properties and auxiliary information (terrain attributes, remote sensing indices, geology map, existing soil map, and geomorphology map). Root-mean-square error (RMSE) and mean error (ME) were considered to determine the performance of the models. Among the studied models, GLM showed the highest performance to predict pH, EC, clay, silt, sand, and CCE, whereas the best model is not necessarily able to make accurate estimation. According to RMSE%, DSM has a good efficiency to predict soil properties with low and moderate variabilities. Terrain attributes were the main predictors among different studied auxiliary information. The accuracy of the estimations with more observations is recommended to give a better understanding about the performance of DSM approach over low-relief areas.     

Controlling energy consumption in residential buildings using air infiltration in humid climates

Environment, Development and Sustainability - Given the ever-increasing people’s need for housing, affordable housing and environmental comfort are important, and the use of inactive design...     

Determination of appropriate service quality attributes for household toilets in rural settlements of India based on user perception

In many developing countries, including India, governments have implemented programs for improvement of environment and health in rural settlements through the provision of a subsidized household toilet with specifications selected and benchmarked from the experts’ perspective with only partial consideration of users’ perception. Provision of household toilets with specifications or service quality as perceived by users is a requirement for the sustainability and sustained use of toilet infrastructure. Users do not judge only the overall quality of a service but also base their judgment on a few attributes which are either perceived to be relatively more important or where there is a wider gap between expectation and perception . This paper presents a review of the service quality attributes of the household toilet as found in the relevant literature and provides a step-by-step approach for identifying appropriate attributes based on users’ perspective. While an initial list of attributes was developed based on literature review, initial selection and modifications of the attributes’ definition and units were carried out as per our judgment. This list was further modified through focus groups discussions and incorporating expert opinions. The final list of attributes is selected based on the stated importance level of attributes as perceived by users. The study finds that the attributes prioritized by the users are different from the experts. While government policies emphasize on the construction of toilet, maintenance of toilet is found an important issue for the users.