Toxic chemical contaminants detected in lichens and mosses in Irati
Toxic chemical contaminants have been detected in lichens and mosses in the Irati Forest. The study concludes that some of these pollutants come from nearby urban centers, others from agricultural burns, and finally, others correspond to pollution caused by pesticides and some electrical insulators that were banned several years ago before they were banned. The study was published in the journal Atmospheric Pollution Research.
Researchers from the University of the Basque Country, the French National Centre for Scientific Research (CNRS) and the University of Navarra have used a species of lichen from Irati (Parmelia sulcata) and a species of moss (Hypnum cupressiforme) as sentinels or biomonitors to determine the organic pollution in the atmosphere. Representative concentrations of various persistent organic compounds have been measured, but it is noted that they are not higher than the concentrations measured at other similar sites.
Persistent organic compounds are toxic and have been studied in this study in three types: PAHs (polycyclic aromatic hydrocarbons) are by-products that are produced especially in combustion processes; PCBs (polychlorinated biphenyls) were used in electrical insulation and are currently banned; and OCPs (organochlorine pesticides) were commonly used in agriculture and are also currently banned.
The results have shown that, in general, PAH concentrations are significantly higher than those of the other two contaminants. The researchers say that pollution that is transported through the atmosphere over long distances should not be underestimated, but the study has shown that urban and agricultural practices that have been around Irati for decades have an impact on air quality.
Researchers have pointed out that some of the pollution may be thought to come and go from urban areas, but the impact of local agriculture is also important to a large extent. Controlled burns continue to occur in some areas around the Pyrenees, where researchers believe many PAHs come from. Thus, in order to reduce the presence of PAH in the atmosphere of the Irati Forest, it is mandatory to control the burns that are made around the forest. On the other hand, traces of pesticides that were used in the past have not been eliminated (OCPs). And as for the PCBs, the researchers suspect that they come from electrical insulators used around the Irabia reservoir. It is likely that the PCBs used in the past have remained there and are still detectable today.
The researchers warn that although the concentrations are not very high, due to their very high toxicity, it is a matter to be monitored to avoid future problems. And they claim that studies like this serve mainly to confirm that these pollutants have a great capacity to reach very distant places from where they have been produced and to accumulate in naturally clean places like Irati. In fact, the jungle of Irati is considered a clean environment, since apart from tourism there is no other human activity than livestock and sustainable agriculture. It is one of the largest preserved protected beech trees in Europe.
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