1,721,045 research outputs found
Assessment of solar UV exposure in the Italian population
Full text linkSolar ultraviolet radiation (UVR) has influenced the evolution
of life on earth and likely caused the development of different skin
pigmentation in humans: those inhabiting low latitudes, with high
UVR intensity, have darker skin pigmentation for protection from
the deleterious effects of UVR, while those in higher latitudes
have developed fair skin to maximize vitamin D production from
much lower ambient UVR. In the last centuries, however, there has been an increase in
human migration from its original areas and human skin
pigmentation is no longer necessarily suited to the environment
where it lives. Dark-skinned populations at low latitudes have
very low incidence of melanoma skin cancer (MSC) and non
melanoma skin cancer (NMSC, such as squamous cell carcinoma,
SCC, and basal cell carcinoma, BCC) but their migration to high
latitudes has seen an increase in the incidence of rickets and
osteomalacia; meanwhile, fair-skinned populations who have
migrated to low latitudes have experienced a rapid rise in the
incidence of MSC and NMSC. Furthermore, changes in habits and
attitudes have meant that many people all over the globe are now
exposed to more, or less, UVR than ever before.
In addition, the documented stratospheric ozone downward
trend due to chlorofluorocarbons (CFCs) has been associated with
an increase of solar ultraviolet radiation B (UVB) at the earth’s
surface, even though UVR changes are also associated with
fluctuations in cloud cover and atmospheric pollution. If ambient
UVR increases, in the absence of changes in personal attitudes
and sun protection, there will be an increase in health diseases due
to excessive UVR exposure. The only positive human benefit from a moderate degree of
solar UVR exposure is the production of vitamin D required for
skeletal health. Recently, there has been a debate within the
scientific community regarding the health duality of UVR.
Various articles have suggested that low vitamin D can be
considered a risk factor for breast, prostate and colon cancers. Kimlin’s research group (Australia) is currently focusing on the
positive and negative effects of UVR on human health in order to
quantify the correct exposure of populations. For such reasons,
evaluation of the personal solar UVR doses on different body
parts and the search for related easy to measure biological
indicators can be helpful in the study of the best levels of
exposure and the understanding of what is still unknown. The purpose of this study was to suggest and test a
methodology for the measuring of personal solar UVR doses and
search for possible biological indicators of its effects. We chose
polysulphone (PS) dosimetry as the main investigative
methodology. Several field experiments were performed, five of
them with groups of volunteers (in vivo) selected among the
Italian population (schoolchildren, sun bathers, vineyard growers,
skiers and hikers), presented and discussed here.
The main result was the data collection of personal UVR
exposures, added to the global dataset as Exposure Ratio (ER)
between the erythemally weighed dose measured by the PS
dosimeter and the corresponding ambient dose on a horizontal
plane measured by a radiometer. Mean (median) values of ER on the chest for schoolchildren,
sun bathers and hikers were respectively 0.07 (0.07), 0.19 (0.19)
and 0.11 (0.07). Since the schoolchildren ER turned out to be the
lowest, we asked whether the dose allowed a sufficient production
of vitamin D, discovering that some children of the sample
showed inadequate modalities of exposure (probably recovered
during the summer months). The study on sun bathers, decided so
as to supply indications on the relationship between the absorbed
doses and the development of the photodermatoses, evidenced that
the latter were not linked to high values of Exposure Ratio but
they rather depended on the genetic characteristics of the
individuals, which probably reacted to the exposure not through
the production of melanin but with an increase in the dilation of
blood vessels, leading to skin reddening.
ER on the forehead for skiers and hikers showed an average
value of 1.01 (1.03) and 0.27 (0.24) respectively, with the difference due to snow albedo. The study on vineyard growers,
carried out in three different seasons (spring, summer and
autumn), supplied an average value of 0.71 (0.69) for the nape and
of 0.46 (0.42) for the arm, with an elevated variability due to the
different atmospheric conditions and to the different duties
between one season and another.
The study also proposed a methodology combining the use of
colorimetric parameters, skin temperature and additional
information (such as the amount of free radicals in the skin) that
were collected during the experiments. All data were analyzed by
means of well known statistical multivariate approaches, namely
PCA (Principal Component Analysis) and Cluster Analysis, useful
when variables are not only correlated but also numerous. Finally,
to interpret the results, an empirical model for the estimation of
short and long term doses was proposed
Tropical storm impact in Central America
No full textIn this study of tropical storm impacts in Central America, the relationship between physical variables (available in 'real time') and damage is explored, and a simple tool for early approximate evaluation of the impact is developed. Land track and energy dissipation appear as the most interesting parameters that modulate the hurricane impact. Because of the difficulty of attaching a monetary estimate to the damage caused in a large number of cases (as is required in a statistical approach), an 'Impact Index' based on the logarithm of casualties is introduced. Thereafter, within a subset of events in which damage in monetary terms is known, a rough link between damage and the Impact Index is derived. Shortly after a new event, as soon as land track and energy dissipation are known, either by means of an empirical equation or using a contour graph, the Impact Index may be determined. Another empirical equation allows a rough estimate of damage in monetary units, but because this estimate is based on a limited number of cases, it must be treated with caution. The methodology is tested for a small set of independent cases. Vulnerability to tropical cyclones depends not only on natural factors but also on sociopolitical conditions. A coupled sociological and environmental approach is believed to be the best way to improve the early impact estimate methodology
Occupational exposure to solar UV radiation. A short review of relevant papers on the quantification of exposure to solar ultraviolet (UV) radiation of outdoor workers
No full textThis paper intends to be a tentative summary of the state of knowledge on the quantifi cation of occupational exposure to solar ultraviolet (UV) radiation by reviewing the relevant literature. The authors have already published some studies on this topic using polysulphone (PS) dosimetry, providing a signifi cant contribution to the few studies on the quantifi cation of UV exposure for professional outdoor workers in Italy. The paper also highlights the importance of such studies in the Mediterranean area and the Italian territory, with high potential to receive intense solar UV doses through most of the yea
La radiazione solare ultravioletta alle Latitudini del Mediterraneo nel trattamento di acque microbiologicamente contaminate
No full textSi stima che circa un miliardo di persone nel mondo sia costretta a fare uso di acqua biologicamente contaminata, con il rischio di contrarre malattie derivanti da microorganismi patogeni (diarrea, colera, febbre tifoide, epatite A (WHO/UNICEF/WSSCC, 2000; WHO/UNICEF, 2012)). Questo problema è fortemente sentito nei Paesi in via di sviluppo, per i quali sono state studiate da tempo tecniche di trattamento delle acque in grado di eliminare o almeno ridurre il rischio di contaminazione. Tali tecniche vanno dalle operazioni di filtraggio fino al riscaldamento al punto di ebollizione o all'uso del cloro. La clorazione, molto utilizzata anche nei Paesi sviluppati, presenta numerosi svantaggi legati alle caratteristiche del cloro, che ha un costo, è un elemento corrosivo, necessita di attenti dosaggi ed altera il sapore dell’acqua (WHO, 1997).
Dall'inizio degli anni 80 del secolo scorso è stata sviluppata ed adottata con successo una metodologia a basso costo per decontaminare acqua biologicamente infetta, in piccole quantità e con bassi livelli di torbidità, basata sull’utilizzo della radiazione solare. Il metodo, denominato SODIS (SOlar DISinfection), funziona grazie all’azione germicida della radiazione ultravioletta prevalentemente nella banda 320-400 nm (UVA) combinata a quella della componente infrarossa (lunghezza d’onda maggiore di 700 nm) in grado di far aumentare la temperatura dell’acqua (Acra et al, 1984). L’uso simultaneo di entrambe le porzioni dello spettro solare durante l’esposizione produce un effetto sinergico che accresce l’efficienza del processo di decontaminazione (Wegelin et al., 1994; Sommer et al., 1997).
E’ stato verificato che, al di sotto di 35° di latitudine, circa 6 ore di esposizione alla radiazione solare in condizioni di cielo sereno possono disinfettare totalmente acqua poco torbida contenuta in bottiglie di PET (Polietilene Tereftalato, materiale plastico che lascia passare la radiazione UVA, a differenza del vetro (SANDEC, 2002; Wegelin et al., 2001)). Se la temperatura dell’acqua supera i 50°C, basta una sola ora di esposizione al sole (SANDEC, 2002). L’efficienza della disinfezione dipende quindi in maniera cruciale dalla disponibilità di radiazione UV alla superficie, principalmente nella banda UVA, ma l’informazione relativa, a differenza di quella sulla radiazione solare globale (integrata cioè su tutto lo spettro), non è di facile reperimento, in quanto sono poche le stazioni nel mondo che realizzano misure spettrali nell’ultravioletto solare (Pawlat and Stryczewska, 2001). Ci si propone quindi di mostrare l'esistenza e la loro utilità nel contesto suddetto in ambito nazionale, sfruttando i dati spettrali di radiazione solare UV disponibili nelle stazioni di Roma Sapienza ed Aosta ARPA VdA (Diémoz et al, 2011).
L'interesse per questo tipo di analisi nasce dalla considerazione che le regioni mediterranee risultano frequentemente esposte, nei periodi di siccità, a problemi legati all’approvvigionamento di acqua soprattutto per uso agricolo. Nel nostro Paese, inoltre, in agricoltura viene spesso usata acqua potabile, con conseguente consumo di preziose risorse naturali e di energia. Si vogliono quindi ottenere informazioni sulla decontaminazione microbiologica delle acque su scala media (quindi non solo sulla piccola scala rappresentata dalla bottiglia di PET ma anche, ad esempio, in vasche di raccolta di dimensione di qualche metro quadrato) nelle regioni mediterranee. E' evidente che tale problema mostra numerose incognite di tipo pratico alla verifica sperimentale.
In questo contributo si vogliono: 1) fornire valutazioni di carattere generale sulla potenzialità delle dosi solari alle nostre latitudini; 2) illustrare sinteticamente la progettazione sperimentale, che verrà realizzata nei prossimi mesi
- …
