Anatomy of a domino accident: Roots,triggers and lessons learnt

On July 24th, 2010, several explosions and fires devastated a hydrocarbon processing plant in Kharg Island, Iran. Four workers were killed and many others were severely injured. The plant became out of service for 80 days. The way the accident happened and its sequence was representing as a domino accident. In this paper, events leading up to the disaster have been analyzed in details. Graphic presentation techniques such as Fish Bone Analysis and Event Sequence Diagram (ESD) have been utilized to enhance the understanding of the accident mechanism. Finally major lessons learnt from this domino accident have been addressed.     

Soil organic carbon sequestration as affected by afforestation: the Darab Kola forest (north of Iran) case study

Following the ratification of the Kyoto Protocol, afforestation of formerly arable lands and/or degraded areas has been acknowledged as a land-use change contributing to the mitigation of increasing atmospheric CO(2) concentration in the atmosphere. In the present work, we study the soil organic carbon sequestration (SOCS) in 21 year old stands of maple (Acer velutinum Bioss.), oak (Quercus castaneifolia C.A. Mey.), and red pine (Pinus brutia Ten.) in the Darab Kola region, north of Iran. Soil samples were collected at four different depths (0-10, 10-20, 20-30, and 30-40 cm), and characterized with respect to bulk density, water content, electrical conductivity, pH, texture, lime content, total organic C, total N, and earthworm density and biomass. Data showed that afforested stands significantly affected soil characteristics, also raising SOCS phenomena, with values of 163.3, 120.6, and 102.1 Mg C ha(-1) for red pine, oak and maple stands, respectively, vs. 83.0 Mg C ha(-1) for the control region. Even if the dynamics of organic matter (OM) in soil is very complex and affected by several pedo-climatic factors, a stepwise regression method indicates that SOCS values in the studied area could be predicted using the following parameters, i.e., sand, clay, lime, and total N contents, and C/N ratio. In particular, although the chemical and physical stabilization capacity of organic C by soil is believed to be mainly governed by clay content, regression analysis showed a positive correlation between SOCS and sand (R = 0.86(**)), whereas a negative correlation with clay (R = -0.77(**)) was observed, thus suggesting that most of this organic C occurs as particulate OM instead of mineral-associated OM. Although the proposed models do not take into account possible changes due to natural and anthropogenic processes, they represent a simple way that could be used to evaluate and/or monitor the potential of each forest plantation in immobilizing organic C in soil (thus reducing atmospheric C concentration), as well as to select more appropriate species during forestation plan management at least in the north of Iran.     

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.     

Geostatistical Analysis of Spatial and Temporal Variations of Groundwater Level

Groundwater and water resources management plays a key role in conserving the sustainable conditions in arid and semi-arid regions. Applying management tools which can reveal the critical and hot conditions seems necessary due to some limitations such as labor and funding. In this study, spatial and temporal analysis of monthly groundwater level fluctuations of 39 piezometric wells monitored during 12 years was carried out. Geostatistics which has been introduced as a management and decision tool by many researchers has been applied to reveal the spatial and temporal structure of groundwater level fluctuation. Results showed that a strong spatial and temporal structure existed for groundwater level fluctuations due to very low nugget effects. Spatial analysis showed a strong structure of groundwater level drop across the study area and temporal analysis showed that groundwater level fluctuations have temporal structure. On average, the range of variograms for spatial and temporal analysis was about 9.7 km and 7.2 months, respectively. Ordinary and universal kriging methods with cross-validation were applied to assess the accuracy of the chosen variograms in estimation of the groundwater level drop and groundwater level fluctuations for spatial and temporal scales, respectively. Results of ordinary and universal krigings revealed that groundwater level drop and groundwater level fluctuations were underestimated by 3% and 6% for spatial and temporal analysis, respectively, which are very low and acceptable errors and support the unbiasedness hypothesis of kriging. Although, our results demonstrated that spatial structure was a little bit stronger than temporal structure, however, estimation of groundwater level drop and groundwater level fluctuations could be performed with low uncertainty in both space and time scales. Moreover, the results showed that kriging is a beneficial and capable tool for detecting those critical regions where need more attentions for sustainable use of groundwater. Regions in which were detected as critical areas need to be much more managed for using the current water resources efficiently. Conducting water harvesting systems especially in critical and hot areas in order to recharge the groundwater, and altering the current cropping pattern to another one that need less water requirement and applying modern irrigation techniques are highly recommended; otherwise, it is most likely that in a few years no more crop would be cultivated.     

From socioeconomic disparity to environmental injustice: the relationship between housing unit density and community green space in a medium city in Pakistan

Rapid urbanisation, lack of proactive planning and improper allocation of resources may result in socio-economic disparity among and within cities, causing social unrest and environmental injustice in the neighbourhoods. This study aims to examine whether the planning standards for housing schemes in Pakistan are able to maintain equitable access to green spaces within the cities. Ten residential sites in Sheikhupura city with different housing unit sizes and densities were selected for the study. The supply of urban green infrastructure in housing scheme has been assessed: (i) by comparing the percentage of green spaces, including community parks and open spaces and street landscape; and (ii) by calculating per dwelling unit and per capita share of green spaces. These indicators have been studied against the housing density and population density of the schemes by applying correlation and linear regression models. The results show that all the housing schemes plans provide for similar amounts of green space as a percentage of total area. The per capita share of green spaces is very low in high-density areas, but interestingly, the street landscape has a higher potential to contribute to the overall landscape in high-density neighbourhoods, compensating for low per capita green space. Housing unit density and population density must be incorporated in planning standards so planners can effectively devise a mix of community parks, street landscape and private green spaces to help maintain per capita green spaces, and hence environmental resource equality in different parts of the city.     

Factors affecting polycyclic aromatic hydrocarbon biodegradation by Aspergillus flavus

This study investigated the ability of fungi isolated from highly contaminated soil to biodegrade polycyclic aromatic hydrocarbon (PAH) compounds, as well as the effect of several parameters on the biodegradation ability of these fungi. The isolated fungi were identified using ITS rDNA sequencing and tested using 2,6‐dichlorophinolendophenol to determine their preliminary ability to degrade crude oil. The top‐performing fungi, Aspergillus flavus and Aspergillus fumigatus, were selected to test their ability to biodegrade PAH compounds as single isolates. After 15 days of incubation, A. flavus degraded 82.7% of the total PAH compounds, with the complete degradation of six compounds, whereas A. fumigatus degraded 68.9% of the total PAHs, with four aromatic compounds completely degraded. We also tested whether different temperatures, pH, and nitrogen sources influenced the growth of A. flavus and the degradation rate. The degradation process was optimal at a temperature of 30°C, pH of 5.5, and with nitrogen in the form of yeast extract. Finally, the ability of the fungal candidate, A. flavus, to degrade PAH compounds under these optimum conditions was studied. The results showed that 95.87% of the total PAHs, including 11 aromatic compounds, were completely degraded after 15 days of incubation. This suggests that A. flavus is a potential microorganism for the degradation of PAH compounds in aqueous cultures.     

Wheat productivity responses in the rice-based system under different no-till techniques and nitrogen sources

Environmental Science and Pollution Research - No-till wheat is gaining popularity in rice-based cropping system as it provides a better chance for timely planting of wheat, management of crop...