C. Camera

E. S. Ferrari

M. Masetti

M. Tiepolo

R. S. Azzoni

S. Stevenazzi

English

Archivio della ricerca - Università degli studi di Napoli Federico II

Geophysical Research AbstractsVol. 21, EGU2019-PREVIEW, 2019EGU General Assembly 2019© Author(s) 2019. CC Attribution 4.0 license.Atmospheric nitrogen depositions in a highly human impacted area.Stefania Stevenazzi (1), Marco Masetti (1), Corrado Camera (1), Massimo Tiepolo (1), Elena Silvia Ferrari (1),and Roberto Sergio Azzoni (2)(1) University of Milan, Department of Earth Sciences "A. Desio", Italy, (2) University of Milan, Department ofEnvironmental Science and Policy, ItalyHuman perturbation of the nitrogen cycle represents one of the major actions that allowed the human popula-tion to expand and grow in the twentieth century. Nowadays, the environmental consequences of excessive reac-tive nitrogen include atmospheric pollution, nutrition unbalance in aquatic and terrestrial ecosystems, surface andgroundwater quality degradation.Nitrogen can enter the water cycle through atmospheric depositions on ground and water surfaces, leakages frompoint and diffuse sources (i.e., sewage treatment plants or sewage systems, fertilizer and manure applications), anderosion processes affecting nitrogen rich soils. However, integrating all nitrogen forms, processes and scales is stilla major challenge for the understanding and the management of the nitrogen cycle.This study aims to evaluate the impacts of atmospheric pollution on terrestrial and groundwater ecosystems, fo-cusing on nitrogen compounds. A monitoring experiment was set up to collect wet atmospheric depositions in ahuman impacted area with multiple land uses, representing different emission sources (i.e., extended urban areaswith residential buildings and industrial activities, high traffic roads and agricultural activities).Wet deposition is measured at 17 sites, homogeneously distributed in the western sector of Lombardy Region(northern Italy), in the surroundings of Milan. Rainfall collection started in February 2017. By the end of 2018,15 precipitation events were monitored and 144 rainwater samples were collected, involving an average of 10sites per event. After collection, samples were analysed for pH, electric conductivity, ammonium, nitrate, nitrite,major cations (calcium, magnesium, sodium, potassium), and major anions (sulphate, chloride, fluoride). Rainfallchemistry was compared to atmospheric pollution, derived from air quality data from ground-based stations andpollutant emissions data provided by the Regional Environmental Agency (ARPA Lombardia).Results show a direct relationship between high levels of air pollutants (e.g., NO2, SO2, NH3) and relatively highcontaminant concentrations (e.g., NO−3 , SO2−4 , NH+4 ) in rainwater samples. Consequently, rainfalls sampled inautumn-winter or during the fertilisation period (April-May) show higher contaminant concentrations respect tothose sampled in spring-summer or before the fertilisation period. In addition, the chemical composition of rainfallsamples reflects local meteorological conditions and local emission sources. In fact, samples collected in urban oragricultural areas show higher concentrations of specific chemical species (e.g., Ca2+, NO−3 , NH+4 ) in comparisonto those collected in rural areas or close to natural environments (i.e., Alps and Como Lake). Such results allowedestimating wet nitrogen depositions, as nitrate and ammonia, in the study area. The average concentrations ofnitrate and ammonia in precipitation during the monitoring period were 5 mg L−1 and 2.5 mg L−1, respectively.Consequently, given an average annual precipitation of about 800 mm for the period 2016-2018, a wet depositionof inorganic nitrogen equal to 9 kg (NO−3 -N) ha−1 yr−1 and 12.4 kg (NH+4 -N) ha−1 yr−1 was estimated. Asleaching of nitrogen compounds from soils generally increases at nitrogen deposition rates higher than 10 kg ha−1yr−1, this study suggests that the nitrogen atmospheric input to soils should not be neglected when evaluating theimpacts of nitrogen sources to terrestrial and aquatic ecosystems.

Atmospheric nitrogen depositions in a highly human impacted area

https://www.iris.unina.it/bitstream/11588/872910/4/EGU2019-abstract_piogge_preview.pdf

Atmospheric nitrogen depositions in a highly human impacted area

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Archivio della ricerca - Università degli studi di Napoli Federico II