Leisner: "In general, the contamination is getting higher as you get close to cities/industrial used areas. Due to the industry in the past 40-50 years and more and its dust pollution, you can find many heavy metals. But Cadmium and Lead are the most common ones, beside Zinc. But I have to say: Cadmium and Lead are more dangerous than Zinc because Zinc is not toxic for humans."

Leisner: "There are some techniques, but they are all expensive and difficult, also labor-intensive. There is, for example, the method of removing contaminated soil and replace it with clean one. But this is only for small areas, it is not realizable for agricultural fields. Also, the society concentrated much on the contamination of water and the air, but we did not think about the soil in the past. Another method is to pump out the ground water, use a carbon filter and pump it back. But this does not handle the problem with the soil – so your project idea could be a solution in a few years, since there is no adequate solution yet."

Leisner: "Yes, we do – if there are problems of higher concentration of heavy metals we inform the public. We do professional public relation, but it is more about the private citiziens and their garden use than about the agricultural areas and the food. In that case we address the farmers and the chamber of agricultural directly. But when there are problems with the consumer protection, we inform the public, of course. Another point I want to mention now is that there are not only limits for agricultural used areas, there are limits for every place, e.g. for children playgrounds. An interesting fact, not many people know about: There is an information system for substantial soil contamination, not only heavy metals - ( stobo.nrw.de). There is plenty (more than thousands) data about the concentration of different substances in the soil. You can select the city or area you want to know something about and then the substance and the system gives you the required data."

Leisner: "In general: yes! Since there is no suitable solution for the problem of contaminated soil in our area yet, I think you should follow this idea. You need to calculate how much heavy metals the tobacco plant can hyperaccumulate in one season and how long it will take to clean up the soil. Then you should talk to the farmers and chamber of agriculture, if this is realizable. But in my opinion: it is a great idea and I am curious what the progress of the project and the next years will bring in this discussion and the discussion about GMO plants or organism in general."