Ulrik Lohm

The flow of phosphorus in food production and consumption : Linköping, Sweden, 1870-2000

Phosphorus is an important substance for agricultural production of food. Being a limited resource, it is of great interest for regional, as well as global food security. At the same time it presents a pollution problem for the aquatic environment in Sweden since it contributes to eutrophication of surface waters and the Baltic Sea. This study analyses the flow of phosphorus based on consumption and production of food for an average inhabitant of a Swedish city, Linköping, from 1870 until 2000. The study shows the changes in flows within the system of production and consumption of food, as well as between the different processes in this system, such as agriculture, food processing, consumption and waste handling, and output flows to the environment. The main changes in this system over time are a) the increasing flow of phosphorus reaching the consumer and hence the waste handling system, b) the increase in the flow of products from animal production, which mainly causes the increase in (a), and most notably c) the increased input of chemical fertilizer.

Effect of nitrogen and carbon supply on the development of soil organism populations and pine seedlings - microcosm experiment

Series of pots containing Scots pine seedlings and a humus-sand mixture were watered twice weekly for 398 d with different nutrient solutions (control treatment with complete plant nutrient solution less nitrogen; glucose addition; nitrogen addition; glucose and nitrogen addition). Analyses were made of organic and nitrogen contents in the substrate, plant weights and nitrogen contents, nitrogen fixation and respiration rates, abundance, biomass and in some cases species composition of different soil organism populations. The growth rate of pine seedlings was lowest in series supplied with glucose, which is most easily explained by a deficiency of nitrogen due to microbial immobilization. The fungi and yeast were stimulated by addition of an easily available carbon source whereas the bacteria needed both nitrogen and carbon to maintain high biomass. A positive correlation between fungal feeding soil organisms and amount of fungal mycelium was found while a more complex situation prevailed with regard to bacterial numbers and bacterial feeding nematodes. The systems are evaluated in relation to the different treatments and compared with the field situation. (Less)

Impact of microbial-feeding animals on total soil activity and nitrogen dynamics - a soil microcosm experiment

Abstract in Undetermined The long-term impact of microbial-feeding animals on microbial populations was studied in microcosms containing pine seedlings growing in a gamma sterilized humus-sand mixture. Organism communities of diverse complexity were introduced into the microcosms. The two main experimental series contained microorganisms only and microorganisms and microorganism-feeding nematodes, respectively. After 18 months the following analyses were made: soil chemical characteristics, weight and nitrogen content of the seedlings, soil respiration, abundance, biomass, and in some cases, species composition of the different soil organism populations. During the incubation, leaching of nitrogen from the microcosms was measured continuously. The rate of nitrogen leaching from the microcosms increased during the first 6 months. During the remaining 12 months the leaching stabilized at a low rate. Initially, the series with microbial-feeding nematodes had a lower rate of nitrogen loss through leaching compared to the series with only microorganisms added. Towards the end of the experiment the situation was reversed. The pine seedlings showed a very poor growth in all series with no significant differences between the treatments. In the microcosms, bacteria appeared to be the most important microorganism group; fungi, algae and yeasts were present in low amounts. The presence of bacterial feeding nematodes reduced the number of bacteria but did not reduce the soil respiration rate. A significant correlation was obtained between the numbers of nematodes and the respiration rate of the microcosms, which is interpreted as an increased bacterial production rate due to the presence of bacterial-feeding animals. (Less)

GOODS IN THE ANTHROPOSPHERE AS A METAL EMISSION SOURCE A Case Study of Stockholm, Sweden

The aim of this study was to quantify the diffuse emissionsduring use of metal containing goods in the capital of Sweden,Stockholm. The following metals were studied: Cadmium (Cd), Chromium (Cr), Copper (Cu), Lead (Pb), Mercury (Hg), Nickel (Ni) and Zinc (Zn).A major part of the metals are found in a protected environmentwhere degrading processes like corrosion are most limited. However, during the lifetime of some goods the metal release to the environment is significant. The quantitatively most dominant emissions were found for Cu and Zn. The tap water system and roofs/fronts (Cu) represent goods with large exposedareas but with relatively small release rates per unit. In contrast, brake linings, aerial lines and electrical grounding (Cu) and tyres, brake linings and chemicals (Zn) are allgoods with high release rates but mostly limited exposed stocks.High yearly emissions are also found for Pb, ammunition andsinkers dominate the calculated emissions totally. For Cr and Ni, stainless steel represent the major part of the stocks, butcorrosion was estimated to give only a minor contribution to the emissions. Potential emission sources, i.e. stabilisers,pigments and plated goods dominate the exposed Cd stock. Theseemissions were not quantified due to lack of data. Hg is currently phased out, but one major source of emission, i.e. the use of amalgam, will be continuously significant for several decades. The importance of the traffic sector is obvious. The emissionsfrom brake linings (Cu, Zn and Pb), tyres (Zn, Pb, Cr and Ni)and asphalt wear (Cu, Zn, Cr, Ni and Pb) are all of large importance for the total emission from respectively metal.

Fertilizer nitrogen budget in a Scots pine ecosystem attained by using root-isolated plots and15N tracer technique

SummaryThe distribution and quantitative recovery of isotopically labelled fertilizer N was studied in aPinus sylvestris L. stand in central Sweden. The investigation was carried out with root-isolated plots, area 31.2 m2, having a Scots pine aged 120–140 years in the centre of each plot. The fertilizer application rate was 100 kg ammonium nitrate-N per hectare, with either ammonium or nitrate being enriched with15N. The treatments comprised both a single and a split application.The analyses of needle biomass, collected during the first growing season showed that the proportion of labelled N in Ntot was greater in current needles than in older needles. Moreover, the isotopic enrichment was higher in treatments with labelled nitrate than in those with equivalent amount of labelled ammonium.Two growing seasons after fertilization the trees were felled and the distribution of labelled N in the system was determined. The study proved that the greatest proportion of labelled N in Ntot was in the needles and shoots of current and previous years growth. The lowest proportion of labelled N was found in the stem wood and coarse roots.The proportion of labelled N in needles and shoots showed a tendency to increase with height in the crown. As regards bark and wood, the corresponding figures increased from the base to the top of the stem, and was higher in bark than in wood.Between 12 and 28% of the supplied N was recovered in trees, half of which in the needle biomass. In the above-ground parts of the shrub layer 3 to 13% of applied N was recovered. The corresponding recovery figure in the soil varied between 37 and 59% (excluding roots, but including litter and bottom layer). Between 5–8% was recovered in roots <30 mm. On the average, 79% of the supplied N was recovered in the studied part of the system. No significant differences in total15n recovery were found between treatments with ammonium or nitrate source of N, or those with different application techniques.The labelled N not recovered in the investigated part of the system, had presumably been lost by leaching.

Century Perspective of Heavy Metal Use in Urban Areas. : A Case Study in Stockholm

The inflow and stock (amount in use) of heavy metals (cadmium(Cd), chromium (Cr), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni) and zinc (Zn)) in goods in 1995 have been quantifiedin the anthroposphere of Stockholm, Sweden. Statistics on national, regional and local level were used. Contacts were established with representatives from production and constructionin the industrial sector and with authorities. The results show that the stock of Cd is 0,2 kg per capita. For the other heavymetals the corresponding result per capita is: Cr 8, Cu 170, Hg 0,01, Ni 4, Pb 73 and Zn 40 kg. The inflow varies between2–8%of the stock indicating the importance of the stock. The lowestlevels are for Cu and Pb. Heavy metal levels in solid waste are high, between 15–45% of the amount in the inflow (Hg excluded), the lowest values were for Cu and Pb. Thus, recyclingis incomplete. Long life expectancy goods form the majority of the stock but there is a tendency that short life expectancy goods increase their importance in the inflow. Concealedgoods are also more frequent in inflow than in the stock.

Acidification and liming of coniferous forest soil: Long-term effects on turnover rates of carbon and nitrogen during an incubation experiment

Abstract Forest soils from field plots, subjected to long-term acidification by H 2 SO 4 treatment, or to liming, were examined for the effects of treatment on net mineralization and turnover rates of carbon and nitrogen during incubation. The total soil respiration was decreased as a result of acidification, whereas the proportion of labeled C, introduced as 14 C-glucose at start of the incubation, was increased in the CO 2 pool emitted. The accumulation of mineral N (ammonium) was not significantly influenced by acidification, whereas the rate of microbial N turnover, obtained from 15 N-dilution data for the exchangeable NH 4 + fraction, was markedly decreased.

Accumulated Environmental Impact: The Case of Cadmium in Sweden

Abstract In this study, the total flows of cadmium in Sweden in the period 1940–1990 — based on trade statistics, the manufacture of goods and the persistence of products in the environment — have been calculated. The metal industry, the mining of zinc and lead ores and the manufacturing of phosphorus fertilizers have been the dominant sources of industrial cadmium emissions to the environment. The application of fertilizers has led to the depositing of significant amounts of cadmium on agricultural land. Consumption emissions have originated from the use of cadmium in various products, e.g. rechargeable nickel-cadmium batteries, pigments, stabilizers in polyvinyl-chloride plastics and protective plating for metals. The total calculated emissions of cadmium in Sweden, from production and consumption, have, in the past, been approximately 1700 t. The accumulated amount of cadmium used, including cadmium in alloys and as impurities in zinc, is approximately 5000 t. The ‘societal weathering rate’ exceeded the natural rate more than 4 times in 1970, and the present rate (1990) of anthropogenic emissions is still higher than the natural release due to weathering.

Copper Emissions from Fuel Combustion Consumption and Industry in Two Urban Areas 1900–1980

The type of energy system andindustrial structure of urban areas is veryimportant for the total amounts of Cu emitted.The total per capita emission for the New Yorkarea is estimated to be approximately 4 timeslarger than Stockholm municipality between 1900–1980. The latter was mainly the result of largedifferences in energy systems and industrialstructure. Hydro-electric power and non fossilfuels were important energy sources for Stockholmwhile coal was a much more significant fuel forthe New York area. Metal processing hascharacterised the industries of Stockholm whilethe New York area was a national centre forcopper and petroleum refining as well as thechemical industry. In both cases the estimated Cuemissions from fuel combustion and industrydecreased from 1900–1980. But in the case ofconsumption related emissions the time trendsdiffer between the two urban areas. In Stockholmend use was the largest category of Cu emissionsduring the whole time period studied. In the NewYork area consumption related emissions becamethe largest source of Cu emission in the 1950s.

A reconstruction of emission, flow and accumulation of chromium in Sweden 1920-1980

A reconstruction of Cr emissions in Sweden is presented. Estimations of total flows for 1920 in 1980 were based on trade statistics, production of goods and life-length of products in society. A simple model was used to calculate amounts of Cr accumulated in soil and sediment at different times. The importance of production emissions from tanneries and ferrochrome and steel plants is obvious, but, in the future, diffuse emissions of the same magnitude may occur from Cr products within urban areas.