“Clean drinking water is a matter of utter importance, because it is essential for human life and to support terrestrial and aquatic ecosystems.” The appeal of Pope Francis contained in the Encyclical “Praised Yes”, he has given new impetus to the debate on the protection of watersheds. A question long neglected, in which, as often happens, they ended up prevailing economic interests.
Still the use of chemical agents threatens habitats and balances millennial where biodiversity has been able to develop and show itself in all its beauty. According to the latest National Report on Pesticides in Water by the Italian Higher Institute for Environmental Protection and Research (ISPRA), these poisons contaminate 20% of surface water and 10% underground rivers and lakes in the country. Glyphosate is among the substances that exceed the limits more often in the case of surface water. An insult to nature.
130 thousand tons of plant protection products are used in Italy every year. On the top of that, biocides are used in many sectors of human activity and no information is available on the amount and geographical distribution of the release sources. Contamination due to pesticides is a complex phenomenon. It is difficult to predict it, both because of the large number of substances that are used, and because of the multiple paths they can follow in the environment.
The dossier has been prepared on the basis of data provided by the regions and regional agencies for environmental protection, but it does not cover the situation completely nor homogeneously, especially with regard to the central-southern regions of Italy: we have no information about Molise and Calabria regions, whereas data on groundwater is missing for 5 other regions. In other words, the level of water pollution may be higher than ISPRA reported.
In the 2013-2014 period, 29,220 samples were analyzed for 1,351,718 analytical measures, with a significant increase with respect to the previous biennium. In 2014, in particular, the surveys covered 3,747 sampling points, 14,718 samples, and 365 substances were sought (in 2012 they were 335). 224 different substances were found, a significantly higher number compared to the previous years (175 in 2012). The latter data certifies that the conducted surveys have been more efficient.
Herbicides are still the most frequently found substances, especially due to its direct use on the soil, often concomitant with periods of recurrent rainfalls in early spring, which determine a more rapid transport of surface water and groundwater. The presence of fungicides and insecticides has increased too, especially because of the growing number of demanded substances and because their choice is more targeted to be used on the territory.
Surface water contains pesticides in 63.9% of 1,284 of the controlled monitoring points (in 2012 the percentage was 56.9); as to groundwater, 31.7% of 2,463 points were contaminated (31% in 2012). The overall results indicate widespread contamination, greater in surface water, but high also in groundwater. Pesticides, in fact, are present also in deep aquifers that are naturally protected by low-permeability geologic strata. Surface water in 274 monitoring points (21.3% of the total) revealed concentrations that were higher than environmental quality limits.
The substances that exceeded more frequently are the following: glyphosate and its metabolite AMPA (aminomethylphosphonic acid), metolachlor, tricyclazole, oxadiazon, terbuthylazine and its main metabolite, desethyl-terbuthylazine. Glyphosate and its metabolite AMPA are respectively present in 39.7% and 70.9% of surface water monitoring points and we have to make it clear that there is demand for them in Lombardy and Tuscany, where they are among the main factors responsible for exceeding environmental quality limits. In groundwater, 170 points (6.9% of the total) revealed concentrations above the environmental quality limits.
The most frequent substances found above the limit are the following: bentazone, metalaxyl, terbuthylazine and desethyl-terbuthylazine, atrazine and atrazine-desethyl, oxadixyl, imidacloprid, oxadiazon, bromacile, 2,6-diclorobenzammide, and metolachlor. Also the presence of neonicotinoids is widespread both in surface water and groundwater. Imidacloprid and tiametoxan are the most frequent among them, being the cause of their non-compliance with the quality limits. The neonicotinoid are the most spread class of insecticides used worldwide.
A study conducted on a global level (Task Force on Systemic Pesticides, 2015) shows that the use of these substances is one of the main causes of biodiversity loss and bee die-off. Overall, contamination is wider in the Po-Venetian plain. In the five regions of the area are concentrated little less than 60% of the entire national network of monitoring points.
In some regions, contamination is much more widespread than the national average, concerning more than 70% of surface water points in Veneto, Lombardy, Emilia Romagna regions, with peaks of 90% in Tuscany and 95% in Umbria. In groundwater, contamination levels are especially high in Lombardy (50% of the points), in Friuli (68.6%), in Sicily (76%).
Mixes of substances, containing dozens of different components, were found in water more frequently than in the past. Up to 48 substances were found in a single sample. The toxicity of a mix – ISPRA points out – is always higher than that of the individual components. We must, therefore, take into account the fact that humans and other organisms are often exposed to ‘cocktails’ of chemical substances, whose composition is unknown a priori.
According to ISPRA, we have to take note of these findings, confirmed worldwide, and of the fact that the methods used during the authorization process should undergo critical analysis in order to improve risk estimation. Despite the more cautious and aware purchase of these products that was detected during the research, the level of contamination has not dropped. In the 2003-2014 period, in fact, the percentage of points with polluted surface water increased by about 20%, whereas those with groundwater – by about 10%. The environment is saturated and cannot respond physiologically to contamination anymore, making it increasingly difficult to restore the natural conditions.