No abstract

Groundwater pollution is one of the most serious environmental problems in the world. Human activities, e.g. industrial, agricultural and household represent a real threat for groundwater quality. In areas where Groundwater constitutes the main drinking water resources, its vulnerability assessment, to delineate areas that are more susceptible to contamination has become an important element for water resource management and land use planning. Hence, maps of groundwater vulnerability to pollution are becoming more in demand because this essential resource for life represents the main source of drinking water in many parts of the world and particularly in northern China where there is insufficient surface water.This study used the ArcGIS 9.2 software and geographical information system (GIS) techniques to apply an EPA model for determining intrinsic vulnerability of groundwater to pollution in Linfen Basin, Shanxi Province, China. The model is called DRASTIC, representing hydrogeological parameters such as Depth to Aquifer, Net Recharge, Aquifer Media, Soil Media, Topography, Impact of vadose Zones, and Hydraulic Conductivity. The DRASTIC model uses environmental parameters to characterize the hydrogeological setting of any area and to evaluate the aquifer vulnerability. The DRASTIC scores obtained from the model vary from 59 to 147, where the higher value implies the relative greater vulnerability. These values were reclassified into three classes: very low, low and moderate vulnerable zones. The moderate vulnerability zones of Linfen Basin are located in the north and southeastern part of the basin. The moderate vulnerable zones cover around 16.38% of the study area. Huozhou City in the north, Yicheng County, Qu Wo County in the south east are concerned by moderate vulnerability zones.The very low vulnerable zones are well distributed and are mainly located in the middle and south parts of the basin. Some very low vulnerable zones can also be seen in the north east and extreme east parts. Very low vulnerable zones cover about 40.13% of the study area. The remaining parts of the Linfen basin are under low vulnerable zones (43.49%) which are located in the west and Middle West parts of the region.The results of this study can be used to determine where communities should undertake aggressive protection of the groundwater. Regional development planners will benefit from knowledge of local sensitive aquifers.

Background Ileus is common after elective colorectal surgery, and is associated with increased adverse events and prolonged hospital stay. The aim was to assess the role of non‐steroidal anti‐inflammatory drugs (NSAIDs) for reducing ileus after surgery. Methods A prospective multicentre cohort study was delivered by an international, student‐ and trainee‐led collaborative group. Adult patients undergoing elective colorectal resection between January and April 2018 were included. The primary outcome was time to gastrointestinal recovery, measured using a composite measure of bowel function and tolerance to oral intake. The impact of NSAIDs was explored using Cox regression analyses, including the results of a centre‐specific survey of compliance to enhanced recovery principles. Secondary safety outcomes included anastomotic leak rate and acute kidney injury. Results A total of 4164 patients were included, with a median age of 68 (i.q.r. 57–75) years (54·9 per cent men). Some 1153 (27·7 per cent) received NSAIDs on postoperative days 1–3, of whom 1061 (92·0 per cent) received non‐selective cyclo‐oxygenase inhibitors. After adjustment for baseline differences, the mean time to gastrointestinal recovery did not differ significantly between patients who received NSAIDs and those who did not (4·6 versus 4·8 days; hazard ratio 1·04, 95 per cent c.i. 0·96 to 1·12; P = 0·360). There were no significant differences in anastomotic leak rate (5·4 versus 4·6 per cent; P = 0·349) or acute kidney injury (14·3 versus 13·8 per cent; P = 0·666) between the groups. Significantly fewer patients receiving NSAIDs required strong opioid analgesia (35·3 versus 56·7 per cent; P < 0·001). Conclusion NSAIDs did not reduce the time for gastrointestinal recovery after colorectal surgery, but they were safe and associated with reduced postoperative opioid requirement.

Groundwater is water present below the surface of the earth in underground streams and aquifers. It is the main source of water supply in arid and semi-arid regions of northwestern China. Studies, in recent years have reported increased cases of aquifer contamination due to different factors such as rapid urbanization and industrialization. Using DRASTIC model, this study attempts to measure vulnerability of ground water to contamination in the Datong Basin, located in Northern China. To reduce subjectivity, a sensitivity analysis was performed to evaluate the influence of a single parameter on aquifer vulnerability.

The results show that 32.5% of the total study area is under a “highly vulnerable zone”. In addition the most sensitive parameter to contamination is aquifer media (A), followed in importance by hydraulic conductivity (C), topography (T), depth to water (D), soil media (S), and impact of vadose zone (I). Net recharge (R) is the least sensitive parameter to pollution. Aquifer vulnerability maps developed in this study are valuable tools for environmental planning and predictive groundwater management.

This study evaluates land use /land cover changes (LULCC) in Wuhan city, China, between 1987-2006 using satellite imagery data. Spatial and temporal dynamics of LULCC were quantified using three landsat TM images (1987, 1994 and 2006). The maximum likelihood supervised classification algorithm and post classification Change detection technique in GIS were also used. The analysis revealed that forest and urban growth over the study period changed by 15.57% and 8.66% respectively, resulting in a significant decrease in the area of cultivated land (16.88%) and water (7.35%). For the three main towns that make up Wuhan city, Wuchang increased in water, urban and cultivated land, and a decrease in forest cover; Hanyang increased in urban area and decreases in cultivated land, water and forest, while in Hankou, cultivated land and forest increased, urban and water covers decreased. The overall accuracy of the derived LULCC maps ranged from 88% to 92%. The outcomes of this research will benefit society through the creation of reliable land cover information for better decision making. However, to identify how information diffusion and spatial externalities could affect the spatial pattern and composition of land cover over time, agent-based techniques could be more helpful.