2023-10-16 15:59:52
Las lettuces They are recommended to carry a healthy diet and if they are from kilometer 0 are more beneficial for the environment, but are they safe coming from the city? And can they be used for something else?
Answering these questions is what the research group of the Polytechnic University of Madrid (UPM) Prospecting and Environment (AVERAGE), together with researchers from the University of Copenhagen.
Together they have carried out a study in which lettuces were exposed to different degrees of atmospheric pollution in different places in the city of Copenhagen.
According to the results obtained, the evaluation of the health risk derived from the consumption of lettuce grown in a urban environment indicates some safe levels (as long as clean soil is used during planting and the lettuce is washed properly before consumption).
In this research, lettuce was used as potential bioindicators of air pollution in a city.
Furthermore, these vegetables grown in the areas most affected by gas emissions and particulate matter, had higher concentrations of pollutants, so they can serve as a complementary system to the network of fixed stations. Air quality control.
In a previous studythe research team had demonstrated the feasibility of using rapeseed y kale for biomonitorizar air quality. In this new research, some of the pending uncertainties have been addressed, although on this occasion using lettuce as potential bioindicators.
This work arises from the need to respond to two of the challenges that humanity is currently facing: food shortage worldwide and the catmospheric pollution of cities (the WHO estimates that 99% of the population is exposed to pollution levels higher than recommended).
In this work, four objectives were set: evaluate the use of lettuce for measurement of suspended particlescheck the reduction of pollutant concentration in the leaves after washinglove the bioavailability of heavy metals and metalloids analyzed and determine whether lettuces grown in urban areas on a clean substrate They are safe for consumption.
To do this, several lettuce seedlings were placed in different parts of the urban center of Copenhagen (next to a main avenue and in a park) and in the peri-urban area (in an orchard surrounded by a forest, in the garden of a house and next to a highway), as well as a climate chamber to establish reference levels. After a period of exposure of one month and a half, each lettuce was divided into two halves, one of which was washed with distilled water. To determine the concentration of contaminants, two methods were used, a total extraction and another bioaccesible (which simulates the fraction soluble in the gastrointestinal tract and available for absorption), analyzing 24 elements.
Washing the samples managed to reduce the concentration of some elements associated with traffic and other industrial activities by up to 20 times, because these are attached to particles deposited on the surface of the leaves.
The results showed that there was a relationship between the concentration of accumulated elements and the exposure environmentobserving an enrichment of anthropogenic pollutants in the samples located in the center of the city and near transportation routes, as well as an increase in substances typical of marine aerosol at all points since it is a coastal city.
Therefore, lettuces could be used as a affordable add-on system to conventional networks air quality monitoring for the measurement of suspended particles and inorganic contaminants.
In second place, washing the samples managed to reduce up to 20 times the concentration of some elements associated with traffic and to other industrial activities, indicating that these are mainly attached to particles deposited on the surface of the leaves and have not been transferred to plant tissue. Consequently, a measure as simple as washing products grown in urban gardens before consumption can greatly limit the intake of toxic substances.
Human health risk assessment
Thirdly, as the PROMEDIAM research group at the UPM had previously confirmed, the bioaccessible fraction of metals and metalloids was significantly lower than the total content. Therefore, environmental consultants and public administration should consider this parameter during the characterization of a site and the corresponding human health risk assessment with the purpose of Do not overestimate the value of the risk and, in this way, not undertake unnecessary decontamination actions or, if carried out, with lower economic cost and less environmental impact.
Finally, it was verified that the concentrations of the lettuces grown on a clean substrate they did not exceed legal limits established by the European Commission for this type of foods and, furthermore, a estimation of the daily intake of contaminants due to their consumption nor did it exceed the maximum tolerable intake levels recommended by the main health agencies (EFSA and NAM).
Despite this, as highlighted Miguel Izquierdoone of the UPM researchers participating in the study, “to extend these results and guarantee the suitability of foods grown in urban areas that contribute to fight the global food crisis, “The contribution of other agricultural products and in cities with worse air quality indices should be examined.”
Rights: Creative Commons.
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