美国燃料粮食的爆炸性需求威胁着世界粮食安全和政治稳定

2006年的粮食既已颗粒归仓,现在是盘库和规划未来的时候了。2006年,全球共收获了19亿6700万吨粮食,比估计的消费量20亿4000万吨约少7300万吨。短缺几近4％,创下历史记录。更清醒地看,近7年中的6年里,世界粮食生产一直不敷使用。结果,世界库存的谷物降到只够消费57天,是34年来的最低水平。而上次达到这么低的水平时,小麦和稻谷的价格翻了一番。     

Gas chromatographic and mass spectrometric characterization of terbufos sulfoxide and its hydration product

Abstract

Terbufos sulfoxide is a primary metabolite of the organophosphorus insecticide terbufos. The identification of terbufos sulfoxide was determined by combined gas chromatography/mass spectrometry and the direct probe. Mass spectral data are presented and discussed. The data indicate that thermal degradation occurred in the heated GC column. A hydration product of terbufos sulfoxide was detected and its mass spectral data are discussed.     

Closing Remarks

Considerable attention has been paid in recent years to photochemical smog pollution close to the earth's surface and to stratospheric ozone depletion. There is reason to suspect that the next round of scientific concern will be devoted to the perturbations in the “free troposphere.” Tropospheric ozone has been building up in many regions of the northern hemisphere. Ozone changes in the upper troposphere will exert a considerable impact on global warming. This could affect moisture levels, cloud amount and distribution, precipitation, and atmospheric dynamics on different scales.

This paper analyzes: (1) the physical and chemical processes contributing to changes in tropospheric ozone concentration; (2) the observational evidence of previous ozone change; and (3) results drawn from computer modelling of past and future radiative forcing caused by rising ozone concentrations in the upper troposphere.

The solar and longwave radiative model developed by Wang et al. (1991) was used for calculating the change in radiative forcing to the troposphere-surface system that can be ascribed to changing concentrations in ozone and other greenhouse gases. Nitric oxide emission from aircraft are a prime suspect for the observed increases in upper tropospheric ozone. The inference can be drawn that a radiative forcing of 0.2 to 0.35 Wm^-2 will result from a doubling of aircraft emissions over the next two decades. This will amount to 10 to 25 percent of the radiative forcing attributable to CO₂ alone for the same period. The effect of doubling aircraft emissions will increase as stratospheric ozone concentrations recover from the recent buildup of harmful chlorofluorocarbons. A large fraction of the radiative forcing that occurred during the 1970 to 1990 period can be attributed to increases in tropospheric ozone as opposed to increases in other greenhouse gases.     

Fisheries regulatory regimes and resilience to climate change

Climate change is already producing ecological, social, and economic impacts on fisheries, and these effects are expected to increase in frequency and magnitude in the future. Fisheries governance and regulations can alter socio-ecological resilience to climate change impacts via harvest control rules and incentives driving fisher behavior, yet there are no syntheses or conceptual frameworks for examining how institutions and their regulatory approaches can alter fisheries resilience to climate change. We identify nine key climate resilience criteria for fisheries socio-ecological systems (SES), defining resilience as the ability of the coupled system of interacting social and ecological components (i.e., the SES) to absorb change while avoiding transformation into a different undesirable state. We then evaluate the capacity of four fisheries regulatory systems that vary in their degree of property rights, including open access, limited entry, and two types of rights-based management, to increase or inhibit resilience. Our exploratory assessment of evidence in the literature suggests that these regulatory regimes vary widely in their ability to promote resilient fisheries, with rights-based approaches appearing to offer more resilience benefits in many cases, but detailed characteristics of the regulatory instruments are fundamental.     

The microbiological control of mine waste pollution

The removal of heavy metals and neutralisation of acidity in mine waste waters by algae and bacteria are reviewed. Algal growths in artificial meander systems have been shown to remove significant quantities of heavy metals and fine particulates from mine waste waters. Bacterial systems for the oxidation of ferrous iron and the reduction of sulphate leading to neutralisation of acidity are described. The use of bacterial extracellular polymers in the removal of heavy metals from solution is discussed with reference to its application to acid mine waters. It is concluded that a combination of bacterial and algal systems with process optimisation, including nutrient amendment, may provide suitable treatment for mine waste waters. Metal-resistant bacteria may also be important in reclamation, where it is possible that they can confer some degree of tolerance on the plants used to revegetate metal-contaminated tailings dumps.     

Heavy metal binding by the polymeric organic fractions of sewage sludges

Organic complexes in sewage sludge play an important role in the speciation and transformation of metals into potentially more toxic and bioavailable forms. Two organic fractions, bacterial extracellular polymer and fulvic acid, were extracted from mixed liquor and digested sewage sludge by methods established as the most appropriate. The homogeneity of the extracts was verified using gel permeation chromatography. Conditional stability constants and complexation capacities of the organic fractions from the sludges with copper, cadmium, nickel and zinc have been determined using equilibrium dialysis titration. Organic fractions extracted from digested sludge demonstrated a greater capacity to complex metals over mixed liquor extracts. Copper formed stronger complexes than nickel with the mixed liquor biomass and cadmium exhibited the greatest affinity for digested sludge organic matter.     

Analysis of volatile organic compounds in water,waste water and an industrial effluent

Three analytical methods have been evaluated for the determination of volatile organic compounds in water. These techniques have been subsequently applied to the study of a trade effluent discharge problem.     

Acclimatisation to nitrilotriacetic and in the activated sludge process

The period of acclimatisation prior to the biodegradation of nitrilotriacetic acid in an activated sludge pilot plant was studied in a series of experiments. The effects of low and high influent heavy metals concentrations upon acclimatisation are reported.     

Spatial distribution of mercury in the sediments and riparian environment of the River Yare, Norfolk, UK

Concentrations of total mercury (T-Hg) were determined in sediments and riparian (bankside) soils from the River Yare, Norfolk, UK to assess the current extent of contamination arising from a historical point source discharge. The results demonstrate that the spatial distribution pattern in surficial sediments and soils follows that of a distinct pollution plume with an initial increase 2-3 km downstream from the point source discharge at Whitlingham Sewage Treatment Works (STW) outfall. Average T-Hg concentrations in the surficial sediments ranged from 0.1 to 8.13 mg kg(-1); bankside soil concentrations ranged from 0.1 to 2.63 mg kg(-1). There has been a decline in downstream background sediment concentrations of Hg over time. This is likely to be the result of burial by fresh relatively uncontaminated sediments and possibly in the lower reach as a consequence of the influence of the freshwater-saline interface occurring near Cantley. Channel morphology was also shown to be an important factor in determining the large variations of Hg concentrations between sample points within transects. The predominant source of Hg to the soils appears to be due to dredging and the deposition of sediments during flooding.