Estimates of residual dairy manure nitrogen availability using various techniques

It is common practice to repeatedly apply dairy manure to the same fields. To accurately assess the total plant availability of manure nutrients, it is necessary to account for the nutrients remaining in soil from previous manure applications. A field experiment studying manure nitrogen (N) uptake by corn (Zea mays L.) was conducted from 1998 to 2003 on a Plano silt loam (fine-silty, mixed, mesic, Typic Argiudolls). Plots received two rates of semisolid manure either every year, every 2 yr, or every 3 yr to estimate first-, second-, and third-year dairy manure N residuals. Residual manure N availability was estimated from single and multiple manure applications using (i) the fertilizer N equivalence method, (ii) the apparent recovery (difference) method, (iii) relative effectiveness method, and (iv) recovery of (15)N-labeled manure. Second-year availabilities after a single manure application using the fertilizer equivalence, difference, and relative effectiveness methods were estimated to be 12, 8, and 4% of total manure N applications, respectively. Estimates of third-year availability by these methods were 3, 1, and 5%, respectively. Measurement of (15)N recovered from labeled manure was 6 and 2% in the second and third year, respectively. Fertilizer equivalence, difference, and relative effectiveness methods showed great year to year variability, reducing the confidence in the residual manure N availability estimates by these methods, but using (15)N-labeled manures reduced variability substantially. Based on this and other studies, we suggest that second- and third-year residual N availability from a single application of semisolid dairy manure would be 9 to 12%, and 3 to 5% of the original manure N application, respectively.     

Decommissioning of offshore oil and gas facilities: a comparative assessment of different scenarios

A material and energy flow analysis, with corresponding financial flows, was carried out for different decommissioning scenarios for the different elements of an offshore oil and gas structure. A comparative assessment was made of the non-financial (especially environmental) outcomes of the different scenarios, with the reference scenario being to leave all structures in situ, while other scenarios envisaged leaving them on the seabed or removing them to shore for recycling and disposal. The costs of each scenario, when compared with the reference scenario, give an implicit valuation of the non-financial outcomes (e.g. environmental improvements), should that scenario be adopted by society. The paper concludes that it is not clear that the removal of the topsides and jackets of large steel structures to shore, as currently required by regulations, is environmentally justified; that concrete structures should certainly be left in place; and that leaving footings, cuttings and pipelines in place, with subsequent monitoring, would also be justified unless very large values were placed by society on a clear seabed and trawling access.     

Use of geographic information systems for assessing groundwater pollution potential by pesticides in Central Thailand

This study employed geographic information systems (GIS) technology to evaluate the vulnerability of groundwater to pesticide pollution in Thailand. The study area included three provinces, Kanchana Buri, Ratcha Buri, and Suphan Buri, located in west-central Thailand. Factors used for the vulnerability assessment included soil texture, slope, land use, well depth, and rainfall. These vulnerability factors were reclassified to a common scale, and a weighted average was computed to yield a vulnerability score. Vulnerability factors and weights were assigned considering pesticide concentrations in 90 wells throughout the study area. Well depth was the most significant vulnerability factor. Groundwater vulnerability maps were generated for several pesticides. The eastern, agricultural part of the study area has relatively deep wells and fine soils. Shallow wells are present in the mountainous west; however, fewer pesticides are applied in that region. Consequently, much of the study area had a medium groundwater vulnerability rating, although there were pockets of high vulnerability, for example, in agricultural areas with shallow wells. The groundwater vulnerability maps are effective for identifying locations warranting more detailed groundwater pollution and vulnerability investigations.     

Polybrominated diphenyl ether in the East Asian environment: a critical review

Polybrominated diphenyl ethers (PBDEs) have been extensively used as flame retardants in consumer goods. Sufficient evidence shows that PBDEs have been rapidly accumulating in the environment worldwide. In Asia, deca-bromodiphenyl ether has been produced and used in large quantities, while penta-BDE has largely ceased in the mid-1990s. This paper summarizes and critically reviews the status of PBDE pollution in East Asia, with emphases on the comparisons with Europe and North America and the interpretation of the differences. In general, the concentrations of PBDEs in atmosphere, sludge, human and biological samples of East Asia are comparable to or lower than those in Europe and North America. However, in the sediments of waters near densely populated and heavily industrialized areas, PBDE levels are among the highest ever reported in the literature. In Japan and China, concentrations of PBDEs in sediment cores showed an increasing trend for the past 20-30 years. Also, PBDEs levels in human breast milk in Japan increased about 10-fold in the past 20 years. The presence of PBDEs in fur seal has increased about 150-fold in 1994 than that in 1972. Regional and inter-continental transport cannot be confirmed due to insufficient information. However, the detection of a number of PBDE congeners in a pristine lake on the Qinghai-Tibet Plateau may be an evidence of their long-range transport.     

The Clean Development Mechanism and Sustainable Development in China''''s Electricity Sector

1 INTRODUCTIONEnergy and environmental issues in China have receivedsignificant attention in both the peer-reviewed literatureand in international energy and environmental policymaking in the last number of years. China's coal dominatedenergy consumption results in significant regional pollutionproblems, most notably acid rain that affects nearly 1/3rdof China's landmass and air pollution that plagues manyof its major cities. China now ranks as the top emitterof sulphur dioxide (SO2) pol…     

Energy use,blue water footprint,and greenhouse gas emissions for current food consumption patterns and dietary recommendations in the US

This article measures the changes in energy use, blue water footprint, and greenhouse gas (GHG) emissions associated with shifting from current US food consumption patterns to three dietary scenarios, which are based, in part, on the 2010 USDA Dietary Guidelines (US Department of Agriculture and US Department of Health and Human Services in Dietary Guidelines for Americans, 2010, 7th edn, US Government Printing Office, Washington, 2010). Amidst the current overweight and obesity epidemic in the USA, the Dietary Guidelines provide food and beverage recommendations that are intended to help individuals achieve and maintain healthy weight. The three dietary scenarios we examine include (1) reducing Caloric intake levels to achieve “normal” weight without shifting food mix, (2) switching current food mix to USDA recommended food patterns, without reducing Caloric intake, and (3) reducing Caloric intake levels and shifting current food mix to USDA recommended food patterns, which support healthy weight. This study finds that shifting from the current US diet to dietary Scenario 1 decreases energy use, blue water footprint, and GHG emissions by around 9 %, while shifting to dietary Scenario 2 increases energy use by 43 %, blue water footprint by 16 %, and GHG emissions by 11 %. Shifting to dietary Scenario 3, which accounts for both reduced Caloric intake and a shift to the USDA recommended food mix, increases energy use by 38 %, blue water footprint by 10 %, and GHG emissions by 6 %. These perhaps counterintuitive results are primarily due to USDA recommendations for greater Caloric intake of fruits, vegetables, dairy, and fish/seafood, which have relatively high resource use and emissions per Calorie.     

Recent Changes in Stream Flashiness and Flooding,and Effects of Flood Management in North Carolina and Virginia

The southeastern United States has undergone anthropogenic changes in landscape structure, with the potential to increase (e.g., urbanization) and decrease (e.g., reservoir construction) stream flashiness and flooding. Assessment of the outcome of such change can provide insight into the efficacy of current strategies and policies to manage water resources. We (1) examined trends in precipitation, floods, and stream flashiness and (2) assessed the relative influence of land cover and flow‐regulating features (e.g., best management practices and artificial water bodies) on stream flashiness from 1991 to 2013. We found mean annual precipitation decreased, which coincided with decreasing trends in floods. In contrast, stream flashiness, overall, showed an increasing trend during the period of study. However, upon closer examination, 20 watersheds showed stable stream flashiness, whereas 5 increased and 6 decreased in flashiness. Urban watersheds were among those that increased or decreased in flashiness. Watersheds that increased in stream flashiness gained more urban cover, lost more forested cover and had fewer best management practices installed than urban watersheds that decreased in stream flashiness. We found best management practices are more effective than artificial water bodies in regulating flashy floods. Flashiness index is a valuable and straightforward metric to characterize changes in streamflow and help to assess the efficacy of management interventions.     

A review of the drivers of 200 years of wetland degradation in the Mekong Delta of Vietnam

This paper examines the anthropogenic factors that have contributed to wetland loss and degradation in the Mekong Delta, Vietnam from 1816 AD to present. Our analysis is framed over five historical periods and highlights the role that seven drivers of wetland degradation have played in the Mekong Delta, including: resettlement and economic development policies; population growth and urbanization; demand for food and reclaiming wetland for agriculture; construction of canals construction of dykes flood protection systems; expansion of travel systems (waterway and roads); and exploitation of wetland natural resources. Of these, government policies for resettlement and economic development seem to have had the greatest impact on wetland loss and degradation in the Mekong Delta throughout the course of history. As a result of these factors, only 0.068 million hectares of the original 4.0 million hectares of the Mekong Delta currently remains as primary swamp forest ecosystem. History suggests that future management of the Mekong Delta should take a holistic approach that includes a better understanding of the implications of past decisions on wetland loss.