Abbandono del territorio e dissesto idrogeologico in Appennino bolognese: analisi delle dinamiche e degli interventi di gestione idraulico-forestale

The abandonment of less productive fields and agro-forest activities has occured in the last decades, interesting large mountain areas in all mediterranean basin. Until the fifties, agricultural practices dealt mainly with soil surface and surface runoff control systems. However, the apparent sustainability of soil use results often in contrast with historical documents, witnessing heavy hydrogeological instability, in naturally fragile areas. The research focused on the dynamics and effects of post-coltural land abandonment in a critical mountain area of the Reno River. The Reno River rappresents a typical Tuscan-Emilian Apennines Watershed where soil erosion occurs under very different conditions depending on interactions between land use, climate, geomorphology and lithology. Landslides are largely rappresented, due to the diffusion of clay hill slopes. Recent researches suggest that climatic variability will increase as a consequence of global climate change, resulting in greater frequency and intensity of extreme weather events, which could increase rates of erosion, landslides reactivations and diffusion of calanchive basins. As far as hill slopes are concerned, instability is today basically due to intrinsic factors, as the Apennine range is a rather young formation, in geological terms, and is mainly formed by sedimentary rocks with high occurrence of clays. Therefore landslides and rockfalls are very frequent, while surface soil erosion is generally low and anyway concentrated in the low Apennine, where intensive farming is still economically worth. The study, supported by GIS use, analyses the main fisical characteristics of the area and the historical changes of land use, and focalizes the dynamics of spontaneous reafforestation. Futhermore, the research studies the results of soil bioengineering and surface water control solutions for the restablishment of landslides occured in the last period. Infact soil bioengineering has been recently used in different situations in order to consolidate slopes and hillsides and prevent erosion; when applied, it gave good results, both in terms of engineering efficiency and vegetational development, expecially if combined with a good hydraulic control, thus proving to be an actual alternative to other techniques with heavier environmental impacts. Research into the specific site features and the use of proper plant species is vital to the success of bioengineering works.

Emerging contaminants in agricultural ecosystems: impact of selected pharmaceutical on water and soil ecology and pratical implications

Pharmaceuticals are useful tools to prevent and treat human and animal diseases. Following administration, a significant fraction of pharmaceuticals is excreted unaltered into faeces and urine and may enter the aquatic ecosystem and agricultural soil through irrigation with recycled water, constituting a significant source of emerging contaminants into the environment. Understanding major factors influencing their environmental fate is consequently needed to value the risk, reduce contamination, and set up bioremediation technologies. The antiviral drug Tamiflu (oseltamivir carboxylate, OC) has received recent attention due to the potential use as a first line defence against H5N1 and H1N1 influenza viruses. Research has shown that OC is not removed during conventional wastewater treatments, thus having the potential to enter surface water bodies. A series of laboratory experiments investigated the fate and the removal of OC in surface water systems in Italy and Japan and in a municipal wastewater treatment plant. A preliminary laboratory study investigated the persistence of the active antiviral drug in water samples from an irrigation canal in northern Italy (Canale Emiliano Romagnolo). After an initial rapid decrease, OC concentration slowly decreased during the remaining incubation period. Approximately 65% of the initial OC amount remained in water at the end of the 36-day incubation period. A negligible amount of OC was lost both from sterilized water and from sterilized water/sediment samples, suggesting a significant role of microbial degradation. Stimulating microbial processes by the addition of sediments resulted in reduced OC persistence. Presence of OC (1.5 μg mL-1) did not significantly affect the metabolic potential of the water microbial population, that was estimated by glyphosate and metolachlor mineralization. In contrast, OC caused an initial transient decrease in the size of the indigenous microbial population of water samples. A second laboratory study focused on basic processes governing the environmental fate of OC in surface water from two contrasting aquatic ecosystems of northern Italy, the River Po and the Venice Lagoon. Results of this study confirmed the potential of OC to persist in surface water. However, the addition of 5% of sediments resulted in rapid OC degradation. The estimated half-life of OC in water/sediment of the River Po was 15 days. After three weeks of incubation at 20 °C, more than 8% of 14C-OC evolved as 14CO2 from water/sediment samples of the River Po and Venice Lagoon. OC was moderately retained onto coarse sediments from the two sites. In water/sediment samples of the River Po and Venice Lagoon treated with 14C-OC, more than 30% of the 14C-residues remained water-extractable after three weeks of incubation. The low affinity of OC to sediments suggests that the presence of sediments would not reduce its bioavailability to microbial degradation. Another series of laboratory experiments investigated the fate and the removal of OC in two surface water ecosystems of Japan and in the municipal wastewater treatment plant of the city of Bologna, in Northern Italy. The persistence of OC in surface water ranged from non-detectable degradation to a half-life of 53 days. After 40 days, less than 3% of radiolabeled OC evolved as 14CO2. The presence of sediments (5%) led to a significant increase of OC degradation and of mineralization rates. A more intense mineralization was observed in samples of the wastewater treatment plant when applying a long incubation period (40 days). More precisely, 76% and 37% of the initial radioactivity applied as 14C-OC was recovered as 14CO2 from samples of the biological tank and effluent water, respectively. Two bacterial strains growing on OC as sole carbon source were isolated and used for its removal from synthetic medium and environmental samples, including surface water and wastewater. Inoculation of water and wastewater samples with the two OC-degrading strains showed that mineralization of OC was significantly higher in both inoculated water and wastewater, than in uninoculated controls. Denaturing gradient gel electrophoresis and quantitative PCR analysis showed that OC would not affect the microbial population of surface water and wastewater. The capacity of the ligninolytic fungus Phanerochaete chrysosporium to degrade a wide variety of environmentally persistent xenobiotics has been largely reported in literature. In a series of laboratory experiments, the efficiency of a formulation using P. chrysosporium was evaluated for the removal of selected pharmaceuticals from wastewater samples. Addition of the fungus to samples of the wastewater treatment plant of Bologna significantly increased (P < 0.05) the removal of OC and three antibiotics, erythromycin, sulfamethoxazole, and ciprofloxacin. Similar effects were also observed in effluent water. OC was the most persistent of the four pharmaceuticals. After 30 days of incubation, approximately two times more OC was removed in bioremediated samples than in controls. The highest removal efficiency of the formulation was observed with the antibiotic ciprofloxacin. The studies included environmental aspects of soil contamination with two emerging veterinary contaminants, such as doramectin and oxibendazole, wich are common parasitic treatments in cattle farms.