STUDIO ECOTOSSICOLOGICO DI ALCUNI AGROFARMACI

Gli agrofarmaci comprendono un'ampia gamma di preparati per la difesa delle piante contro gli attacchi di organismi nocivi, oltre che per il controllo delle erbe infestanti e la regolazione dei processi fisiologici dei vegetali. Le sostanze attive contenute nei prodotti commerciali, ovvero le sostanze che esercitano la loro azione tossica nei confronti delle specie da combattere, possono rivelarsi dannose anche per altri esseri viventi che costituiscono gli organismi essenziali degli ecosistemi. Le norme attualmente in vigore prevedono che l'autorizzazione all'immissione in commercio di un agrofarmaco sia preceduta da una approfondita valutazione del rischio ambientale. Tale valutazione tiene conto delle proprietà fisico-chimiche del prodotto, delle sue proprietà ecotossicologiche, delle quantità e modalità di impiego dei prodotti, della persistenza della sostanza attiva nell'ambiente e della relativa capacità di diffusione. La normativa in vigore, dunque, comporta l'esame delle modalità di distribuzione delle sostanze attive e dei loro prodotti di degradazione e/o metaboliti nei diversi comparti ambientali ed una valutazione dei danni che tali preparati possono determinare sulle popolazioni animali e vegetali "non-bersaglio" (pesci, alghe, uccelli, organismi del suolo, insetti utili, ecc.). In quest’ottica, i test ecotossicologici permettono di definire una relazione causa-effetto, anche se in genere i risultati ottenuti, validi per le condizioni sperimentali utilizzate, non consentono di estendere le conclusioni ad altre specie o a sistemi naturali complessi, dal momento che non possono tenere conto delle complesse interazioni fra biota ed ambiente. Inoltre, poiché organismi differenti evidenziano una diversa sensibilità alle componenti attive ed ai coformulati presenti negli agrofarmaci e nessun biotest è in grado di coprire da solo l’intera varietà di risposte ai diversi tipi ed ai vari intervalli di concentrazione di ciascun xenobiotico, è opportuno implementare test multispecie in cui gli ambiti di sensibilità non si sovrappongano ma, piuttosto, siano complementari. Gli organismi da utilizzare nei test multispecie vengono solitamente scelti in base alla loro rappresentatività (un procariote, un vegetale, un animale superiore) ed in base alle loro relazioni con la catena trofica. Proprio in quest’ambito s’inserisce il nostro lavoro, realizzato con l’obiettivo di valutare la tossicità di quattro agrofarmaci (oxasulfuron, una solfonilurea; imazetapyr, un imidazolinone; dicloran, una nitro anilina; mepanipirim, una anilinopirimidina) e delle miscele dei loro prodotti di degradazione fotochimica, utilizzando tre differenti test di tossicità: il test di tossicità acuta con Daphnia Magna, il test di tossicità acuta con i batteri bioluminescenti della specie Vibrio fischeri (Microtox) e il test di fitotossicità con Lactuca sativa. Fra i quattro agrofarmaci testati il mepanipirin è quello che si è dimostrato maggiormente tossico, in quanto attivo su tutti e tre gli organismi utilizzati

Landslides, floods and sinkholes in a karst environment: the 1–6 September 2014 Gargano event, southern Italy

Abstract. In karst environments, heavy rainfall is known to cause multiple geohydrological hazards, including inundations, flash floods, landslides and sinkholes. We studied a period of intense rainfall from 1 to 6 September 2014 in the Gargano Promontory, a karst area in Puglia, southern Italy. In the period, a sequence of torrential rainfall events caused severe damage and claimed two fatalities. The amount and accuracy of the geographical and temporal information varied for the different hazards. The temporal information was most accurate for the inundation caused by a major river, less accurate for flash floods caused by minor torrents and even less accurate for landslides. For sinkholes, only generic information on the period of occurrence of the failures was available. Our analysis revealed that in the promontory, rainfall-driven hazards occurred in response to extreme meteorological conditions and that the karst landscape responded to the torrential rainfall with a threshold behaviour. We exploited the rainfall and the landslide information to design the new ensemble–non-exceedance probability (E-NEP) algorithm for the quantitative evaluation of the possible occurrence of rainfall-induced landslides and of related geohydrological hazards. The ensemble of the metrics produced by the E-NEP algorithm provided better diagnostics than the single metrics often used for landslide forecasting, including rainfall duration, cumulated rainfall and rainfall intensity. We expect that the E-NEP algorithm will be useful for landslide early warning in karst areas and in other similar environments. We acknowledge that further tests are needed to evaluate the algorithm in different meteorological, geological and physiographical settings

Landslides, floods and sinkholes in a karst environment: the 1–6 September 2014 Gargano event, southern Italy

In karst environments, heavy rainfall is known to cause multiple geohydrological hazards, including inundations, flash floods, landslides and sinkholes. We studied a period of intense rainfall from 1 to 6 September 2014 in the Gargano Promontory, a karst area in Puglia, southern Italy. In the period, a sequence of torrential rainfall events caused severe damage and claimed two fatalities. The amount and accuracy of the geographical and temporal information varied for the different hazards. The temporal information was most accurate for the inundation caused by a major river, less accurate for flash floods caused by minor torrents and even less accurate for landslides. For sinkholes, only generic information on the period of occurrence of the failures was available. Our analysis revealed that in the promontory, rainfall-driven hazards occurred in response to extreme meteorological conditions and that the karst landscape responded to the torrential rainfall with a threshold behaviour. We exploited the rainfall and the landslide information to design the new ensemble-non-exceedance probability (E-NEP) algorithm for the quantitative evaluation of the possible occurrence of rainfall-induced landslides and of related geohydrological hazards. The ensemble of the metrics produced by the E-NEP algorithm provided better diagnostics than the single metrics often used for landslide forecasting, including rainfall duration, cumulated rainfall and rainfall intensity. We expect that the E-NEP algorithm will be useful for landslide early warning in karst areas and in other similar environments. We acknowledge that further tests are needed to evaluate the algorithm in different meteorological, geological and physiographical settings

Nitrate pollution in different hydrogeological zones of the groundwater flow system in the volcanic structure of Mt. Vulture (Basilicata, Southern Italy).

A survey on groundwater quality of Mt. Vulture volcanic structure, undertaken from 2003 to 2005, indicates that nitrate pollution is a serious problem affecting the water resources. The Mt. Vulture, inactive volcano, is located on the northern border of the Basilicata region (southern Italy) and it formed in an area of strong tectonic instability. The analysis of geological, stratigraphical, hydrogeological and hydrochemical data contributes to delineate the groundwater hydrodynamics of Mt. Vulture that represents a huge aquifer characterized by precious mineral waters. The rapid expansion of intensive agricultural activities has greatly increased the use of nitrogen (N) fertilizer. In this study has been reconstructed the map of the nitrate concentrations in groundwater. The comparison between the winter-summer nitrate data and the intrinsic pollution vulnerability map (Spilotro et al., 2004) evidences the determining role in different hydrogeological zones of the groundwater flow system in the seasonal variations of the concentrations and in the total dilution of the pollutant

The effects of nitric oxide on striatal serotoninergic transmission involve multiple targets: an in vivo microdialysis study in the awake rat

The role of endogenous nitric oxide (NO) in N-methyl-D-aspartate (NMDA)-induced modulation of serotonin (5-HT) release in the striatum of freely moving rats has been studied using microdialysis technique. NMDA-induced increase in 5-HT release was significantly inhibited by selective nitric oxide synthase (nNOS) inhibitor S-methylthiocitrulline (S-Me-TC), ONOO- scavenger L-cysteine (L-cys), and guanylate cyclase (GC) inhibitor 1H[1,2,4]oxadiazolo[4,3-a]quinoxalin-l-one (ODQ). These data suggest that modulation of 5-HT levels is linked to the formation of NO produced by NMDA receptor activation and that endogenously produced NO increases 5-FIT concentrations both by stimulating? formation of 3'-5'-cyclic monophosphate (cGMP) and conversion of ONOO-. 2004 Elsevier B.V. (C) All rights reserved

Phytoremediation applications in natural condition and in mesocosm. The uptake of cadmium by Lemna minuta Kunth, a non-native species in Italian watercourses

Metal pollution in water and soil is an environmental and public health issue. Cadmium (Cd) is included in the list of priority hazardous substances in the European Water Framework Directive. Phytoremediation system is a cost-effective, plant-based approach that takes advantage of the ability of plants to concentrate elements and compounds from the environment and to metabolize various molecules in their tissues. We studied the presence and the importance of an invasive species, such as Lemna minuta, in the environment and the effects of Cd pollution on this species. Growth, removal, and tolerance were evaluated for different Cd concentrations and different times of plant exposure. Overall, the results show that L. minuta has a good capacity of growth, metal bioconcentration, and tolerance up to 3 days of exposure at 0.5 and 1.5 mg L−1 of Cd. In particular, L. minuta was able to accumulate Cd up to 3771 mg kg−1 on dry mass basis. We can conclude that L. minuta possesses a great capability of Cd absorption and accumulation, thus supporting a potential use of this species in designing a metal bioremediation system in phytoremediation field

Photochemical transformation and toxicity of dichloran in pure water and water sampled from lake Pamvotis

Photodegradation of dichloran, 2,6-dichloro-4-nitroaniline, a fungicide used to control fungi diseases on fruits and vegetables due to Botrytis, Monilia, Rhizopus, Sclerotinia, has been investigated. In distilled water as well as in the water sampled from the lake Pamvotis (Greece) the fungicide follows a first order reaction kinetics although with different half-lives: 117 and 74 h, respectively. To better understand the ecological behaviour of this chemical, the acute toxicity of photodegradation intermediates has been evaluated on Daphnia magna (freshwater crustacean, water flea), Vibrio fischeri bacteria (Microtox) and Lactuca sativa. The toxicity tests evidenced that the mixture of dichloran by-products was more toxic than the pure active compound