Results of Valeria Gelman's Master's thesis 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.

Valeria Gelmanin pro gradu osoittaa, että Helsingin katoilla puhtaalla kasvualustalla viljeltyjä vihanneksia voi turvallisesti syödä, sillä niistä ei löytynyt merkittäviä määriä saasteita.