1,721,037 research outputs found
Potential effects of heavy metals on health of north Adriatic sea cetaceans
No full textMarine mammals have proved to be important bioindicators for the medium-long term changes in environments due to their relatively long life and the position on the top of the food chains. The large amount of adipose tissue they possess represents an accumulation compartment for different persistent contaminants. When lipids are re-mobilised, i.e. during cold periods and pregnancy/lactation or following stressing episodes, contaminants can re-enter blood circulation, thus causing secondary intoxication or inducing pathological alterations.
Despite huge literature available on contaminants determination and quantification in different cetacean species, little is known about the pathogenic or pathological effects these levels can induce. No specific reference toxicity threshold exists, and thresholds defined for other mammalian (terrestrial) species are generally used. Cytotoxicity reports concerning in vitro cetacean cells culture, anyway, seem to be in agreement with these threshold.
Most dangerous chemicals are those little or no biodegraded, thus persisting for a long time in the environment and concentrating at various ecosystem levels. These chemicals include heavy metals and metalloids, i.e. mercury, lead, cadmium, copper, arsenic, chromium and nickel, and the great family of organochlorine compounds, i.e. insecticides, dioxins and PCBs.
In present work we report about results obtained from the analysis of tissues of 10 stranded Tursiops truncatus, one Physeter macrocephalus and one Grampus griseus collected in Northern Adriatic Sea. Concerning T3 and T4 quantification, a comparison of data obtained from the same subjects and from different species collected by Haifa University is also presented. Obtained results allowed the definition of body burden level in cetaceans of Northern Adriatic Sea and to evaluate possible toxic effects induced by these levels, with a certain attention to immune system. It was possible to consider that at least in 4 out of 10 dolphins some lymphocytic toxicity, increase in apoptosis, reduction in lymphocytic activity and proliferation could occur, thus inducing a higher sensitivity to infectious diseases in affected animals. Thyroid hormones have also been quantified in the tissues of the two cetaceans population (Northen Adriatic and Israel). Obtained data are to be considered as innovative as regards applied method and species considered
Metalli pesanti nei cetacei dell'Adriatico settentrionale e possibili effetti sub-letali
No full textIl lavoro presenta i risultati delle ricerche effettuate relativamente ai tassi di metalli pesanti in cetacei spiaggiati lungo le coste dell'Adriatico settentrionale e alcune speculazioni relative ai possibili effetti sub-tossici esercitati nei soggetti stessi
Ribaltamento delle ceppaie di castagno - Individuazione delle zone a rischio e proposte selvicolturali
No full textOverage and abandoned chestnut coppice stands show an increasing frequency of uprooting events. The present study shows that these events mainly regard single tall stools located in steep slopes along depressions This situation increases the risk for dam-break and debris flow. Uprooting seems primarily caused by precarious stool static whereby the exaggerated above-ground mass cannot be counteracted by a too small and overage root apparatus. Coppicing or thinning before an age of 30 years old and diversification of the chestnut coppice structures would strongly contribute to reduce the risk of uprooting
ACCUMULATION OF ORGANOTIN COMPOUNDS IN MUSSELS FROM NORTHERN ADRIATIC COASTS.
No full textA rapid method (fused silica capillary GC/MS) was developed for quantitative analysis of organotin compounds in mussel tissues and sediments. Samples were homogenized with n-hexane and organotin compounds were pentylated via the Grignard reaction in ethyl ether. Recoveries of organotin compounds were 85-98% from both mussels and sediments samples. High concentrations of TBT were found in sediments from Ravenna harbour, while levels in mussels were generally lower. These preliminary determinations represent the first comparative monitoring of TBT in both types of samples collected in the marine environment of the Northern Adriatic
Heavy metals in dolphins from the Northern Adriatic Sea and potential subtle toxic effects
No full textEnvironmental pollution represents one of the main threats for marine ecosystems conservation. Top predator are particularly exposed to contaminants and; due to their anatomical and physiological characteristics, cetaceans can reach very high pollutants tissue body burdens (i.e. organochlorine and heavy metals). These marine mammals and are thus considered as good indicators of marine environmental pollution where , and among them heavy metals are one of the major contaminants classes.
Present research reports about theon quantification of heavy metals in tissues of stranded bottlenose dolphins (Tursiops truncatus) from Northern Adriatic Sea and presents show some speculation on possible subtle adverse effects exerted by these levels on the general health of the animals.
Stranded dolphin were collected along Northern Adriatic Sea coasts during a 5 years period and underwent necropsy for the determination of the causes of death. ; during examination, Tissue samples organs were sampled and stored at -20°C until analysis, which was performed with an Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) technique. Quantified metals were Cr, Ni, Cu, Zn, Hg, As, Se, Cd and Pb and data are reported as mg/kg (ppm) on a wet weight basis. When possible, gender and age of the animals were recorded.
All metals were at detectable levels, presenteding a huge variation among animals and tissues. Interestingly, sSome of the most common contaminants for marine environment were detected at low levels, often below limit of quantification, also in accumulation target organs like liver and kidney. Mean heavy metals detected were to be considered as low, but high enough to exert a potential immunotoxic effect on animals, as the levels detected are comparable to those which proved to be active in vitro on lymphocytic cytotoxicity, apoptosis, lymphocytic proliferation and phagocytic activity, as confirmed by some anatomo-pathological observations of lymph node swelling. Some speculation on potential reproductive effect of detected heavy metals levels are also proposed, even if no clear evidence of altered reproductive activity was observed.
From obtained data there seems to be a reduced exposure to heavy metals, even thought a higher susceptibility to infectious diseases can be considered for studied animals
DETERMINAZIONE DI COMPOSTI STANNORGANICI IN TESSUTI DI PESCE MEDIANTE HRGC/MS.
No full textNegli ultimi anni si è assistito ad un notevole aumento della produzione mondiale di composti stannorganici, passando dalle 5 mila tonnellate del 1950 alle oltre 80.000 attuali. Gli impieghi di questi composti chimici sono numerosi e vari: i derivati mono- e dialchilici sono impiegati come stabilizzanti ella produzione di PVC, mentre i composti trialchilici e trifenilici sono impiegati come biocidi in agricoltura e come principi attivi nelle vernici antivegetative. Le proprietà tossiche di questi composti variano a seconda del grado di sostituzione dei gruppi organici legati all'atomo di stagno. In particolare si sono dimostrati esrtremamente tossici per gli organismi acquatici i trialchilici (TBT), poiché tendono ad accumularsi in essi con elevati fattori di concentrazione. In questa ricerca ci si è proposti di valutare l'accumulo di un composto stannorganico, il tributistagno cloruro (TBTC) e di eventuali suoi metaboliti nel rene, fegato, milza e tessuto muscolare di Carpa (Cyprinus carpio L.) mediante gas cromatografia ad alta risoluzione abbinata con spettrometria di massa (HRGC/MS). Per questa analisi ambientale si è messa a punto una tecnica semplice ed efficiente di estrazione, utilizzando della polvere di diatomee purificata (Extrelut) e n-esano tenuti a contatto con i campioni omogeneizzati di organi e tessuti per 5'. L'eluato era successivamente portato a secco mediante un evaporatore rotante in presenza di un flusso di azoto a temperatura ambiente ed infine ripreso con 500 μl di n-esano. La derivatizzazione veniva effettuata con l'aggiunta del reattivo di Grignard (bromuro di pentilmagnesio in etere etilico), eliminandone l'eccesso con l'aggiunta di alcune gocce di acqua distillata e 10 ml di acido solforico 1 M. La fase organica veniva infine concentrata in flusso di azoto e portata a volume finale di 10 μl. La determinazione degli stannorganici è stata effettuata mediante un gascromatografo HP 5890 serie II dotato di colonna capilare (Altech SE 30 m x 0,25 mm); la temperatura del'inietore era 260 °C, quella della colonna era invece fissata con un'isoterma iniziale di 120 °C programmata per un incremento di 10 °C/min sino a 280 °C, e come gas di trasporto è stato utilizzato l'elio con un'elevata velocità lineare in colonna di 25 cm/sec. Per l'analisi sono stati iniettati 2 μl di campione. Come rivelatore è stato utilizzato uno spettrofotometro di massa quadrupolare HP 5989 con le seguenti condizioni operative: energia elettronica 70 eV, temperatura alla sorgente 200 °C ed elettromoltiplicatore 2.200 V. Lo strumento è stato impiegato seguendo la tecnica SIM ("selected ions monitoring"), cioé in selezione degli ioni più caratteristici e significativi derivati dall'analisi degli standard: m/z 301, 303, 305 per i TBT; m/z 315, 317, 319 per i DBT. Per verificare la validità del metodo utilizzato nella determinazione quantitativa in frammentografia di massa, sono state eseguite prove di recupero su campioni lofilizzati non contaminati da stannorganici, cui è stata aggiunta una soluzione 0,01 ng/μl di TBTC e di DBTC ottenendo una percentuale di recupero superiore al 90%. E' risultato che già dopo la prima settimana di somministrazione di TBTC, le carpe dimostravano di accumulare quantità molto elevate (timo 21,18 mg/kg e rene 21,12 mg/kg). Ciò denota come tali sostanze, proprio grazie alla loro lipofilia, siano facilmente assorbite dal pesce. Oltre all'accumulo di TBTC negli organi e tessuti attraverso questa tecnica analitica estremamente sensibile è stato possibile osservare la presenza di un metabolita, il dibutistagno cloruro (DBTC), probabilmente derivato da processo di dealchilazione a livello epatico, come è stato osservato nei mammiferi. Comunque non è stato osservato apprezzabile accumulo nel tessuto muscolare, cioé la parte edibile del pesce, per cui non vi è alcun rischio derivante dal consumo di esso
ACCUMULATION OF ORGANOTIN COMPOUNDS IN MUSSELS COLLECTED FROM NORTHERN ADRIATIC COASTS.
No full textA rapid method was developed for quantitative analysis of organotin compounds in mussels and sediments by fused silica capillary gas chromatography/mass spectrometry (GC/MS). The samples were homogenised with n-hexane and the organotin compounds were pentylated via Grignard reaction with pentylmagnesium bromide in ethyl ether. The mass spectrometer was used in SIM mode (Selected Ion Monitoring) to enable the simultaneous determination of more than twenty compounds. Recoveries of the organotin compounds were about 85-98% form mussel tissues and sediment samples. The detection limits were 0.05-0.08 μg/g in mussel tissues and 0.03-0.06 μg/g in sediments. This technique was developed in response to our need to process large numbers of environmental samples with a minimum time investment
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