Browsing by Subject "urban agriculture"

Sort by: Order: Results:

Now showing items 1-2 of 2
  • Gelman, Valeria (Helsingfors universitet, 2014)
    The increased rates of population growth and urbanization worldwide raises the question of food security and self-reliance in cities. In view of this situation, in recent years there has been a re-emergence of urban agriculture in its traditional form and in new variations, such as on urban rooftops. A number of rooftop urban farms exist in the world; however, very few studies have been done to establish the quality of crops they produce, specifically concerning the concentrations of contaminants. The main purpose of this study was to investigate levels of contamination in edible plants grown on urban rooftops. I determined concentrations of polycyclic aromatic hydrocarbons (PAH) and trace metals in the biomass of three types of horticultural crops grown in the city of Helsinki, Finland. Lettuce, radish and peas were planted on five rooftops in various areas of Helsinki and control samples were acquired from local food stores and markets. Both groups of crops were analyzed for concentrations of 11 trace elements using the Elan 6000 ICP-MS and 16 PAHs using Shimadzu GC-MS-QP2010 Ultra system with the AOC-20i /AOC-20s autosampler. Additionally, lettuce and pea samples from the roofs were analyzed washed and unwashed to establish levels of particulate contamination on the surface of plants that can be mechanically removed through washing. Results obtained suggest that concentrations of PAHs and trace metals in rooftop vegetables in Helsinki are very low and the differences in their concentrations compared to control (store) samples are insignificant. This demonstrates that the consumption of vegetables produced in uncontaminated soil on urban roofs in Helsinki is safe. All samples showed concentrations well below the safety limits for heavy metals and PAHs established in the European Union (EC, 2006). Finally, there was a difference in concentration of PAHs and trace metals between washed and unwashed samples, however most of the results did not show statistical significance.
  • Jansson, Kristina (Helsingin yliopisto, 2018)
    The Finnish food security is currently good, but Finland must respond to threats linked to natural or man-made disasters, climate change and reliance on imported resources. This master’s thesis examines the potential of urban agriculture (UA) as part of the urban food system. Rooftop data, crop yield statistics and the Finnish Nutrition Recommendations 2014 are used to build a case study in which self-sufficiency percentages, nutritional factors and shading are calculated for the Pasila area in central Helsinki. Calculations based on the total potential green rooftop area and open rooftop farming in Pasila show that 4,51 % of the resident population’s energy needs could be supplied with the potato, or 3,87 % of their protein needs with the green pea. Allocating half of the area to the potato and half to the green pea decreases the self-sufficiency percentages, but results in a more even ratio between energy and protein. Adding kale increases the number of essential vitamins and minerals which can be supplied: 500 g of each of the three plants covers the daily recommended intake for 12 of the 19 vitamins and minerals listed in the Finnish Nutrition Recommendations 2014, compared to zero for the potato only and seven for the combination of the potato and the green pea. In addition to the available area, at least farming methods (e.g. open field, aquaponics and greenhouses), crop yield potential, food choices and food wastage influence the food self-sufficiency potential. In central Helsinki shading may affect as much as half of the rooftop area, which needs to be considered in the choice of plants and architecture; strategies such as placing the tallest building on the northern edge of the area may be beneficial. Though the total self-sufficiency based on open rooftop farming is low, Pasila could be a net producer of potatoes or peas, or grow 46 % of its fresh vegetables measured in weight (kale). Whether UA can contribute to local food security, or food system resilience, may therefore depend on how its objectives are defined: maximum energy and nutrient content, alternative food sources, new opportunities for farmers, wealth retention, or some other indirect mechanism. With the right policies, UA could advance the Ministry of Agriculture and Forestry’s Climate Program by increasing carbon sequestration, reducing food waste and promoting a more plants-based diet. It may also serve the objectives of the Common Agricultural Policy (CAP), including a healthier environment, preserving and creating jobs, protecting local financial interests and contributing to a sound development of our areas