Nitrogen and Phosphorus in the Finnish Energy System, 1900–2003

In producing power, humans move the nutrients nitrogen (N) and phosphorus (P) from their long‐term geological and biological stocks and release or emit them in soil, water, and the atmosphere. In Finland, peat combustion is an important driver of N and P fluxes from the environment to human economy. The flows of N and P in the Finnish energy system were quantified with partial substance flow analysis, and the driving forces of emissions of nitrogen oxides (NOx) were analyzed using the ImPACT model. In the year 2000 in Finland, 140,000 tonnes of nitrogen entered the energy system, mainly in peat and hard coal. Combustion released an estimated 66,000 tonnes of N as nitrogen oxides (NOx) and nitrous oxides (N2O) and another 74,000 tonnes as elemental N2. Most of the emissions were borne in traffic. At the same time, 6,000 tonnes of P was estimated to enter the Finnish energy system, mostly in peat and wood. Ash was mainly used in earth construction and disposed in landfills; thus negligible levels of P were recycled back to nature. During the twentieth century, fuel‐borne input of N increased 20‐fold, and of P 8‐fold. In 1900–1950, the increasing use of hard coal slowly boosted N input, whereas wood fuels were the main carrier of P. Since 1970, the fluxes have been on the rise. NOx emissions leveled off in the 1980s, though, and then declined in conjunction with improvements in combustion technologies such as NOx removal (de‐NOx) technologies in energy production and catalytic converters in cars.     

The Temporal Evolution of Anthropogenic Phosphorus Consumption in China and Its Environmental Implications

Modern human activities greatly disturb substance flows in nature and senselessly discard massive amounts of precious resources to natural waste reservoirs; phosphorus (P) is a good example of this. In this article, substance flow analysis is employed to quantify and explore the temporal evolution of China's P consumption in main metabolic nodes from 1984 to 2008, and then the environmental implications for P flows into both surface waters and natural soil are investigated. Results show that the metabolic nodes of human life and animal husbandry have demanded increasingly more P inputs, while disseminating more and more P wastes, with the waste recycling ratios of these processes dropping, respectively, from 65.9% and 66.1% in 1984 to 50.7% and 40.6% by 2008. These change traits were closely related to national polices including the Household Contract Responsibility System and the Shopping Basket Program, as well as the policy vacuum existing between China's agricultural and environmental administration departments. To achieve high crop yield, increasingly more inorganic P fertilizers have been utilized in China, but their use efficiency has decreased by 46.3%. From 2003 to 2008, the total P load into surface waters was stabilized at about 900.0 kilotons (kt), while the total P load into natural soil increased by more than 3.8 times to 3,131.3 kt P in 2008. City life and the intensive breeding of crops are identified as the main targets for further pollution control and nutrient recycling in China. Some suggestions for achieving environmentally sound practices and resource sustainability in China are proposed at the end of this article.     

Long-term calorie restriction has minimal impact on brain metabolite and fatty acid profiles in aged rats on a Western-style diet

The effect of long-term calorie restriction (CR) on metabolites, fatty acid profiles and energy substrate transporter expression in the brain was assessed in aged rats. Three groups of male Sprague–Dawley rats were studied: (i) a 2 month old ad libitum-fed (2AL group), (ii) a 19 month old ad libitum-fed (19AL group), and (iii) a 19 month old group subjected to 40% CR from the age of 7.5 to 19 months (19CR group). The diet contained high sucrose and low n-3 polyunsaturated fatty acids (PUFA) so as to imitate a Western-style diet. High resolution magic angle spinning-¹H NMR showed an effect of aging on brain cortex metabolites compared to 2AL rats, the largest differences being for myo-inositol (+251% and +181%), lactate (+203% and +188%), β-hydroxybutyrate (+176% and +618%) and choline (+148% and +120%), in 19AL and 19 CR rats, respectively. However, brain metabolites did not differ between the 19AL and 19CR groups. Cortex fatty acid profiles showed that n-3 PUFA were 35–47% lower but monounsaturated fatty acids were 40–52% higher in 19AL and 19CR rats compared to 2AL rats. Brain microvessel glucose transporter (GLUT1) was 68% higher in 19AL rats than in 2AL rats, while the monocarboxylate transporter, MCT1, was 61% lower in 19CR rats compared to 19AL rats. We conclude that on a high-sucrose, low n-3 PUFA diet, the brain of aged AL rats had higher metabolites and microvessel GLUT1 expression compared to 2AL rats. However, long-term CR in aged rats did not markedly change brain metabolite or fatty acid profile, but did reduce brain microvessel MCT1 expression.     

Testosterone affects hormone-sensitive lipase (HSL) activity and lipid metabolism in the left ventricle

Fatty acids, which are the major cardiac fuel, are derived from lipid droplets stored in cardiomyocytes, among other sources. The heart expresses hormone-sensitive lipase (HSL), which regulates triglycerides (TG) breakdown, and the enzyme is under hormonal control. Evidence obtained from adipose tissue suggests that testosterone regulates HSL activity. To test whether this is also true in the heart, we measured HSL activity in the left ventricle of sedentary male rats that had been treated with testosterone supplementation or orchidectomy with or without testosterone substitution. Left ventricle HSL activity against TG was significantly elevated in intact rats supplemented with testosterone. HSL activity against both TG and diacylglyceride was reduced by orchidectomy, whereas testosterone replacement fully reversed this effect. Moreover, testosterone increased left ventricle free fatty acid levels, caused an inhibitory effect on carbohydrate metabolism in the heart, and elevated left ventricular phosphocreatine and ATP levels as compared to control rats. These data indicate that testosterone is involved in cardiac HSL activity regulation which, in turn, may affect cardiac lipid and carbohydrate metabolism.     

Future Redistribution of Cadmium to Arable Swedish Soils: A Substance Stock Analysis

This article describes a stock-based methodology designed to analyze the redistribution of substance stocks to environmental compartments. The methodology is then applied to investigate the requirements and possibilities for avoiding undesired future accumulation of cadmium in Swedish arable soils. A prospective decomposition analysis of human cadmium mobilization is thus performed to estimate the potential amounts that can end up in arable soils through different flows from the cadmium stocks identified. The requirements for cadmium abatement to achieve prescribed goals for accumulation limits are determined and compared with past and current achievements and with the varying qualities of possible abatement methods.
A stock-based methodology adds some important information to traditional scenario techniques based on substance flow analysis. The most obvious is that the fact that stocks are limited actually matters for long-term accumulation of cadmium in arable land. The methodology may also contribute certain indicators, for instance, on abatement requirements, which could serve as a complement to regulation and local quality measures on specific flows at an aggregated policy level. The stock perspective also sheds new light on actions such as increased recycling.
Concerning the specific example used in the study, it is possible to achieve a future addition of cadmium in Swedish agricultural soils that is significantly lower than in the past, although the amount depends to a large degree on activities and policies outside Sweden. Considerable uncertainty exists regarding future depositions from air, especially that from distributed small-scale emissions from fuel burning and reemission of already deposited cadmium from natural media. Measures must also be taken to guarantee a continued low addition in the form of mineral phosphorus fertilizers.     

Estimation of Copper In‐use Stocks in Nanjing,China

Copper (Cu) is an essential but supply‐restricted resource in China. Characterization of in‐use stocks can provide useful instruction for the future recycling of copper. This article attempts to estimate copper in‐use stocks in a Chinese city. To this purpose, an extensive bottom‐up estimate of copper stocks in use in Nanjing in the year 2009 was conducted. The results are a total stock estimate of 295 gigagrams (Gg) of copper or 46.9 kilograms (kg) of copper per capita for 2009. Infrastructure, equipment, and buildings contain 42.0%, 26.1%, and 28.1% of the total stock, respectively, indicating that these three categories are principal potential reservoirs of a secondary copper resource. The copper in transportation amounts to only about 3.7% of the total amount. The per capita stock was compared with similar studies carried out in other regions of the world, and the results show that the Nanjing level is significantly lower than developed countries. On the whole, our results show that electric power transmission and distribution systems, buildings, household durables, and industrial equipment are the four largest potential reservoirs of copper scrap.     

Investigating Cross‐Sectoral Synergies through Integrated Aquaculture,Fisheries, and Agriculture Phosphorus Assessments: A Case Study of Norway

Future phosphorus (P) scarcity and eutrophication risks demonstrate the need for systems‐wide P assessments. Despite the projected drastic increase in world‐wide fish production, P studies have yet to include the aquaculture and fisheries sectors, thus eliminating the possibility of assessing their relative importance and identifying opportunities for recycling. Using Norway as a case, this study presents the results of a current‐status integrated fisheries, aquaculture, and agriculture P flow analysis and identifies current sectoral linkages as well as potential cross‐sectoral synergies where P use can be optimized. A scenario was developed to shed light on how the projected 2050 fivefold Norwegian aquaculture growth will likely affect P demand and secondary P resources. The results indicate that, contrary to most other countries where agriculture dominates, in Norway, aquaculture and agriculture drive P consumption and losses at similar levels and secondary P recycling, both intra‐ and cross‐sectorally, is far from optimized. The scenario results suggest that the projected aquaculture growth will make the Norwegian aquaculture sector approximately 4 times as P intensive as compared to agriculture, in terms of both imported P and losses. This will create not only future environmental challenges, but also opportunities for cross‐sectoral P recycling that could help alleviate the mineral P demands of agriculture. Near‐term policy measures should focus on utilizing domestic fish scrap for animal husbandry and/or fish feed production. Long‐term efforts should focus on improving technology and environmental systems analysis methods to enable P recovery from aquaculture production and manure distribution in animal husbandry.     

Reverse Problem Formulation for Integrating Process Discharges with Watersheds and Drainage Systems

This work introduces a new approach to integrating the discharges of industrial processes with macroscopic watershed systems. The key concept is that environmental quality models (such as material flow analysis) can be inverted and included in an optimization formulation that seeks to determine the maximum allowable target for the process discharges while meeting the overall environmental requirements of the watershed. Because of its holistic nature, this approach simultaneously considers the effects of the inputs and outputs to the watershed (e.g., agricultural, residential, wastewater treatment plants, industrial, and so on) and the various physical, chemical, and biological phenomena occurring within the watershed. An optimization formulation is developed to systematically represent the reverse problem formulation. To illustrate the effectiveness of this approach, a case study is solved to manage phosphorus in Bahr El‐Baqar drainage system leading to Lake Manzala in Egypt. The key environmental and economic aspects are addressed and used to screen plant location and discharges.