lundi 31 octobre 2016

91- Urban agriculture -1- The city to the countryside


This summer during my holidays, I spent a lovely few days with my mother in Bordeaux. During one of our rides, by car, I was struck by a small fact, insignificant at first glance that inhabitants of Bordeaux know very well, without paying attention, or at least without seeing its full impact.
I won't use any name, because my goal is just to reflect and to make you reflect with me on a real problem.

Chateau XX, one of the most famous Chateaux of Bordeaux, is entirely contained in the city. Over time, urban and industrial growth making their work of conquest of new territories, this very famous Chateau with all its vineyards, was left entirely in the city, surrounded by housing and industrial areas, and even intersected by roads, with their train of roundabouts, traffic lights and traffic jams.


It's precisely at one of those traffic lights that my eye was attracted by something small, quite insignificant, and very normal in a vineyard in September: the lovely black grapes.
And what did they have then, those grapes, that have since certainly been harvested, so to get my attention?
They were barely a few meters from the road, from my exhaust pipe, and from all exhaust pipes of all cars, trucks and autobuses that pass by this road daily.

And I asked myself the following question: wines of Château XX, true icons of great wines of Bordeaux production, are they sometimes analyzed to know their urban pollutant content?
I refer in particular to hydrocarbon residues, to nitrogen oxides, to fluorinated compounds, and especially to heavy metals, lead, zinc, cadmium or nickel, of which it's known that the risks are far from trivial.

So I went to the biggest bookstore in the city, known for the huge variety of available books. In the city of Bordeaux, in one of the largest libraries of France, books on Bordeaux wines are countless. So I looked for something on this. But nothing. Nothing and nothing, not even a mere mention of a potential problem. Obviously, nobody questions the quality of the wines of Château XX, nor all Grands Crus of Bordeaux.

Then I decided to search the internet what I could find on the subject. Nothing neither. It's true that we can find a few documents showing the production of a pollution by wineries, but nothing on the subject that concerns me.
Suddenly, I had the idea to look if there is something about the risks of pollution in urban gardens. Bingo! There are various publications, and various studies on the subject, especially conducted by universities in the United States, Ukraine and Germany, and which report risks, both of soil pollution (but this one does not theoretically affect the fruit), and air pollution, therefore fruits pollution by atmospheric deposition.

And then it begs the question.


Indeed, grapes are not washed and brushed one by one after the vintage, and atmospheric deposition therefore likely arrive until the barrique. Molecules like nitrogen oxides decompose probably during the winemaking process. But metals no.

Is it a problem? Maybe not, it is possible that metals are at levels low enough so that there is no health risk.
Yet, according to the above links, plants placed within 10 meters of high traffic roads have a high risk of exceeding European standards.
However, the article also states that the plant barriers are among the most effective ways to reduce the polluting effect. It is reasonable to assume that the bulk of the harvest is in very low levels of pollutants. Or, in the case of wine, the grape is not consumed alone, but mixed with millions of others. It is therefore likely that the levels in wine are low.
But apparently not many people concerned did verify, or in any case, to make it public.
It is likely that it does not present a public health problem. This is especially true in this case, since this Chateau charges prices that don't put this potential risk, to the level of risk to the general public (I saw just last week here in Seville, in the shop gourmet of a department store, a bottle of Chateau XX on sale at more than 450 € ...).

But this situation, involuntary on behalf of Castle XX, who only saw the city moving closer over time, without intervene, is common in agriculture. The more the farm is close to the city, the more it is susceptible to it. This is also the case of all "green belts" around cities, whose local farmers often take advantage of the economic windfall that represents the possibility of direct sale of farm products. Many have also converted their production in organic to attract an ever-growing and eager audience of those "authentic" products.

However, this development that seems inevitable, of a progression from cities to the countryside must not make us forget the negative consequences of this conquest: reduction of agricultural land, disappearance of farmers, rural pollution, and obligation to increase productivity to maintain food capacity.


The media, hungry for sensitive subjects, present too often the farmer as the main responsible for the (supposed bad) food quality (increasingly challenged by NGOs with opaque objectives). But should we evade the growing responsibility of urbanization?
Is the farmer responsible for the pollution caused by urban growth? We don't speak of this pollution and its effects on food, then it is, in my opinion, more worrying that the use of pesticides.
The reality on pesticides is made up in order to accuse them, and also their manufacturers and their users. It is fashionable, we distrust everything. Therefore let's provide suspicion to those that want! It's so easy to sell...
The reality of pollution is hidden because there is no one to blame, no scapegoat. In this case, the accusers (the producers of the show and viewers themselves) would find themselves directly on the dock. It's quite difficult to sell ...


But to go further in this reflection, urban agriculture is in full vogue, especially in the environmentalist community.
Projects of gardens and orchards on roofs, in courtyards and on balconies are legion. There we can produce without pesticide, only by organic techniques, fruits and vegetables we are sure they are healthy.
Is that true?
Is urban pollution better for health that residues of synthetic pesticides?

The revegetation of roofs, facades and buildings is excellent for biodiversity, for health of bees and birds, as well as for air quality in large cities, there is no doubt. But to make a supposedly healthy food resources, there is a step that personally I will not cross ...


At least with pesticide residues, there are serious and numerous references, we can always discuss, but which exist. Very long and comprehensive studies are conducted to determine the action on the health and environment of all licensed molecules. Teams to assess the molecules consist of scientists, physicians and agronomists, all highly skilled and controlled. We can trust their conclusions, whatever some think.
Yet some don't hesitate to affirm that the origin of pollutants could be in pesticides (eg permaculture enthusiasts /).
Does anyone know a pesticide containing lead, cadmium or nickel? There are not any. It's so easy to accuse pesticides of anything, and of the rest also...

For industrial and urban pollutants, there are few references and standards are only for heavy metals. Yet some plants, in particular leaf-foods like salads, spinach, cabbage, and other leaf herbs are particularly exposed to any pollutants having a large collecting area, which increasingly is consumed. This is also the case for a food such as peppers, food that weighs little but has a relation weight/surface very unfavorable.

So, my dear urban gardeners, convinced that your fruits and vegetables are healthier than the ones you buy at the supermarket, you have to know that you probably eat a large number of pollutants for which you are laboratory mice yourselves ...


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