Edible Production on Rooftop Gardens in Paris? Assessment of Heavy Metal Contamination in Vegetables Growing on Recycled Organic Wastes Substrates in 5 Experimental Roofgardens
The growing proportion of humans living in cities has led to urban sprawl and thus to the increasing need for space dedicated to food production within cities. Rooftops offer a high potential in terms of available space, sun exposure and consumer proximity. However, urban agriculture raises many questions about health risks associated with production in high traffic areas. 4 experimental roofgardens installed in different peri-urban zones of Paris were investigated in this work using a mixture of topsoil, green waste compost and coffee grounds with mycelium as growing substrates. Trace metal (TM) concentrations (Pb, Cd, Hg, Cu and Zn) were measured in five growing crops (tomato, parsley, salad, carrot and strawberry) of these roofgardens. TM’s levels were below the health-based guidance values (EU standards) for virtually all fruits and vegetables. TM’s concentration varied by crop type i.e. parsley and salad contained higher level compared to tomato, strawberry and carrot. Atmospheric fallout seemed to be the major source of TM’s in crops especially in the case of parsley. Significant difference was observed between TM’s level in washed and unwashed vegetables dealing with the importance of consumer good practice like as washing and peeling before consumption.
Keywords— Urban Agriculture, Roofgarden, trace metal, growing crops, atmospheric fallout.