The challenge of reducing macroplastic pollution: Testing the effectiveness of a river boom under real environmental conditions.

Improving collection technologies is crucial to develop effective and economically feasible solutions for catching plastic from riverine environments. However, floating booms are being constructed and deployed in river around the world without rigorously testing its effectiveness. In this study, we tested the effectiveness of a boom under realistic conditions for several configurations and treatments (including "C-shape" and "Slash-shape" configurations). For this, we used the same macroplastics that leak out of waste management channels in order to be as realistic as possible. In total we used 52 plastic articles of 13 different polymers. The global effectiveness of the tested C-shape boom was lower than expected under such conditions (around 37 % of retention). The effectiveness of the Slash-shape boom was considerably worst (<10 %). However, the effectiveness varies greatly according to the particular characteristics of the plastic articles (i.e., shape and polymer composition), ranged from 0 to 100 %. For example, the boom could be 100 % effective retaining plastics such as Stylofoam trays and cups, 40-20 % for food-wrappers but 0 % for disposable plates and spoons, straws, monofilament fishing lines, packaging straps, hoses, pipes, elastic bands, etc. It seems that to have a reasonable catch-effectiveness and be cost-efficient, boom designs need to be improved and tested under different environmental conditions before to reach the market. In addition, it is unrealistic to select only high buoyancy plastics for testing them.

UVB (290-315 nm) inactivation of the SARS CoV-2 virus as a function of the standard UV index.

The inactivation time for the SARS CoV-2 virus, mostly by a portion of UVB spectrum (290-315 nm) in sunlight, has been estimated using radiative transfer calculations and a relative wavelength sensitivity virus inactivation action spectrum ALS. The action spectrum is adjusted for the SARS CoV-2 virus using a derived UV dose D90 = 3.2 J/m2 for 90% inactivation to match laboratory results for the inactivation of SARS CoV-2 virus droplets on steel mesh. Estimation of the time for 90% inactivation T90 at a specific geographic location can be simplified using the commonly published or calculated UV index (UVI). The use of UVI has the advantage that information on the amount of ozone, the site altitude, and the degree of cloud cover are built into the published UVI calculation. Simple power-law T90(UVI) = a UVI b fitting equations are derived that provide estimates of T90(UVI) for 270 specific locations. Using the results from the 270 locations, a generalized latitude θ dependence is presented for the coefficients a(θ) and b(θ) that enables T90(θ, UVI) to be estimated for 60°S ≤ θ ≤ 60°N and for noon and 2 h around local solar noon. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11869-021-01099-3.

Ultraviolet Radiation Environment of a Tropical Megacity in Transition: Mexico City 2000-2019.

Tropical regions experience naturally high levels of UV radiation, but urban pollution can reduce these levels substantially. We analyzed 20 years of measurements of the UV index (UVI) at several ground-level locations in the Mexico City Metropolitan Area and compared these data with the UVI values derived from the satellite observations of ozone and clouds (but not local pollution). The ground-based measurements were systematically lower than the satellite-based estimates by ca. 40% in 2000 and 25% in 2019. Calculations with a radiative transfer model using observed concentrations of air pollutants explained well the difference between satellite and ground-based UVI and showed specific contributions from aerosols, O3, NO2, and SO2 in decreasing order of importance. Such large changes in UV radiation between 2000 and 2019 have important implications ranging from human health (skin cancer and cataract induction) to air pollution control (photochemical smog formation).

Climate change and its relationship with non-melanoma skin cancers.

Climate change is affecting both the environment and human behaviour. One significant impact is related to health, as detailed in the IPCC 2014 report. In the present work, and as a contribution to this commemorative special issue to Prof. Dr Jan van der Leun, we present the results of the squamous (SCC) and basal-cell carcinoma (BCC) incidence change in relation to the ambient temperature increase. This increase is produced by global warming, mainly induced by anthropogenic atmospheric emissions of greenhouse gases. We have broadened a previous study conducted by van der Leun et al. (Photochem. Photobiol. Sci., 2008, 7, 730-733), by analysing the effective carcinogenicity of UV dose, for the period 2000-2200 and four climate change scenarios (called RCP2.6, RCP4.5, RCP6.0 and RCP8.5). The corresponding percentage increases of the incidence of SCC for 2100 are 5.8, 10.4, 13.8 and 21.4%, and for 2200 they are 4.3, 12.1, 19.0 and 40.5%. In a similar way, the percentage increases of the incidence of BCC for 2100 are 2.8, 4.9, 6.5 and 9.9% and for 2200 they are 2.0, 5.8, 8.9 and 18.2%. We report the SCC and BCC percentage effective incidence results as a function of time, for the whole 21st century and we extended the analysis to the 22nd century, since people possibly affected (like the Z and T generations, born at the beginning of this century) will have a life expectancy extending up to the final decades of the present century and even to the first ones of the next century.

High-Up: A Remote Reservoir of Microbial Extremophiles in Central Andean Wetlands.

The Central Andes region displays unexplored ecosystems of shallow lakes and salt flats at mean altitudes of 3700 m. Being isolated and hostile, these so-called "High-Altitude Andean Lakes" (HAAL) are pristine and have been exposed to little human influence. HAAL proved to be a rich source of microbes showing interesting adaptations to life in extreme settings (poly-extremophiles) such as alkalinity, high concentrations of arsenic and dissolved salts, intense dryness, large daily ambient thermal amplitude, and extreme solar radiation levels. This work reviews HAAL microbiodiversity, taking into account different microbial niches, such as plankton, benthos, microbial mats and microbialites. The modern stromatolites and other microbialites discovered recently at HAAL are highlighted, as they provide unique modern-though quite imperfect-analogs of environments proxy for an earlier time in Earth's history (volcanic setting and profuse hydrothermal activity, low atmospheric O2 pressure, thin ozone layer and high UV exposure). Likewise, we stress the importance of HAAL microbes as model poly-extremophiles in the study of the molecular mechanisms underlying their resistance ability against UV and toxic or deleterious chemicals using genome mining and functional genomics. In future research directions, it will be necessary to exploit the full potential of HAAL poly-extremophiles in terms of their biotechnological applications. Current projects heading this way have yielded detailed molecular information and functional proof on novel extremoenzymes: i.e., DNA repair enzymes and arsenic efflux pumps for which medical and bioremediation applications, respectively, are envisaged. But still, much effort is required to unravel novel functions for this and other molecules that dwell in a unique biological treasure despite its being hidden high up, in the remote Andes.

Proposal for a modification of the UVI risk scale.

The standardisation of UV information to the public through the UV Index (UVI) has been hugely beneficial since its endorsement by multiple international agencies more than 10 years ago. It has now gained widespread acceptance, and UVI values are available throughout the world from satellite instruments, ground-based measurements, and from forecasts based on model calculations. These have been useful for atmospheric scientists, health professionals (skin and eye specialists), and the general public. But the descriptors and health messages associated with the UVI scale are targeted towards European skin types and UV regimes, and are not directly applicable to the population living closer to the equator, especially for those in the high-altitude Altiplano region of South America. This document arose from discussions at the Latin American Society of Photobiology and Photomedicine's Congress, which was held in Arequipa, Peru, in November 2013. A major outcome of the meeting was the Arequipa Accord, which is intended as a unifying document to ensure co-ordination of UV and health research decisions in Latin America. A plank of that agreement was the need to tailor the UVI scale to make it more relevant to the region and its population. Here we make some suggestions to improve the international applicability of the UVI scale.

Atmospheric dust accumulation on native and non-native species: effects on gas exchange parameters.

Plants are continuously exposed to atmospheric particulate matter (dust), and their leaves are the main receptors of deposited dust. The objective of this study was to assess the effects of dust deposition on leaf gas exchange parameters of 17 native and non-native tree and shrub species growing in Gran San Miguel de Tucumán in northwestern Argentina. Maximum assimilation rate (), stomatal conductance (), transpiration rate (), internal CO concentration (), and instantaneous water-use efficiency (WUE) were measured in cleaned leaves (CL) and dusted leaves (DL) of different species on November 2010, July 2011, and September 2011. In almost all studied species, gas exchange parameters were significantly affected by dust deposition. Values for , , and of DL were significantly reduced in 11, 12, and 14 species compared with CL. Morphological leaf traits seem to be related to reduction. Indeed, L. and (Mart. ex DC.) Standl. species with pubescent leaves and thick ribs showed the highest reduction percentages. Contrarily, and WUE were increased in DL but were less responsive to dust deposition than other parameters. Increases of and WUE were significant in 5 and 11 species, respectively. Correlation analyses between /, /, and / pairs showed significant positive linear correlations in CL and DL of many studied species, including small and tall plants. These results suggest that leaf stomatal factors and shade-induced effect by accumulated dust are primarily responsible for the observed reductions in photosynthesis rate of DL.

UV index values and trends in Santiago, Chile (33.5°S) based on ground and satellite data.

We report on the surface UV index (UVI) variations in Santiago (Chile) a city with high air pollution and complex surrounding topography. Ground-based UV measurements were continuously carried out between January 1995 and December 2011, by using a multi-channel filter radiometer (PUV-510). Ground-based measurements and satellite-derived data retrieved from the Total Ozone Mapping Spectrometer (TOMS), the Ozone Monitoring Instrument (OMI), and the Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY), were compared. We found that satellite-derived UVI products largely overestimate surface UVI. Our ground-based UVI measurements were significantly lower than TOMS-derived UVI data: (46.1±6.3)% (in the period 1997-2003), and OMI-derived UVI data: (47.0±6.3)% (in the period 2005-2007). Clear-sky SCIAMACHY-derived UVI were found to be also nearly systematically greater than ground-based UVI measurements in the period 2002-2011. An exceptionally long period of clear skies between December 2010 and January 2011 was used to test further satellite-derived UVI data; in the whole period, OMI and SCIAMACHY data were 53.1% and 38.3% greater than our ground-based measurements, respectively. These differences are presumably due to aerosol load associated with the local pollution and the complex topography surrounding Santiago. In addition, linear regression allowed us to estimate trends that we use for forecasting. Methodological details are provided below.

[Ultraviolet radiation impact on seasonal variations of serum 25-hydroxy-vitamin D in healthy young adults in Buenos Aires]. / Variaciones estacionales de 25 (OH) vitamina D en jóvenes sanos y su asociación con la radiación ultravioleta en Buenos Aires.

Exposure to sunlight (ES) is the main source of vitamin D. There are few reports regarding the seasonal variations of serum 25(OH) vitamin D in young adults and its correlation with ultraviolet radiation dose (UVRd). Our aims were to determine 25OHD variations in young adults and assess the correlation between 25OHD levels, dietary calcium intake (DCI) and the UVRd. Eighty two healthy volunteers were prospectively studied: 42 women and 40 men. Serum 25OHD, calcium, phosphorus and magnesium were measured at the end of winter and at the end of summer. ES and UVRd were determined hourly in winter and summer. Seasonal variation in serum 25OHD levels was observed with significantly higher levels in summer in both gender. Serum 25OHD <20 ng/ml was more frequently found in winter (42.6% in women and 50% in men). The ES and UVRd were significantly lower in winter vs. summer. ES and UVRd positively correlated with 25OHD only in winter in both men and women. DCI was lower than recommended and did not correlate with 25OHD levels.

Variaciones estacionales de 25 (OH) vitamina D en jóvenes sanos y su asociación con la radiación ultravioleta en Buenos Aires / Ultraviolet radiation impact on seasonal variations of serum 25-hydroxyvitamin D in healthy young adults in Buenos Aires

El estatus de vitamina D depende principalmente de la exposición solar (ES). Son escasos los informes de las variaciones estacionales de 25(OH)vitamina D, 25OHD, en adultos jóvenes y su relación con la dosis de radiación solar ultravioleta (dRUV). El objetivo de este trabajo fue medir variaciones estacionales de 25OHD en adultos jóvenes estableciendo la correlación con la ingesta dietaria de calcio (IDCa) y la dRUV. Se realizó un estudio prospectivo en individuos sanos: 42 mujeres y 40 varones. Se dosaron a fin de invierno y fin de verano: 25OHD, calcio, fósforo y magnesio. Se evaluó ES y dRUV para cada hora del día en invierno y verano. Se observó una variación estacional de 25OHD con valores significativamente mayores en verano tanto en varones como en mujeres. El 42.6% de las mujeres y el 50.0% de los varones tenían 25OHD <20 ng/ml en invierno. La ES y la dRUV fueron significativamente inferiores en invierno que en verano. Sólo en invierno se halló una correlación positiva entre ES y dRUV con 25OHD en ambos sexos. La IDCa fue insuficiente y no correlacionó con 25OHD.

Exposure to sunlight (ES) is the main source of vitamin D. There are few reports regarding the seasonal variations of serum 25(OH) vitamin D in young adults and its correlation with ultraviolet radiation dose (UVRd). Our aims were to determine 25OHD variations in young adults and assess the correlation between 25OHD levels, dietary calcium intake (DCI) and the UVRd. Eighty two healthy volunteers were prospectively studied: 42 women and 40 men. Serum 25OHD, calcium, phosphorus and magnesium were measured at the end of winter and at the end of summer. ES and UVRd were determined hourly in winter and summer. Seasonal variation in serum 25OHD levels was observed with significantly higher levels in summer in both gender. Serum 25OHD <20 ng/ml was more frequently found in winter (42.6% in women and 50% in men). The ES and UVRd were significantly lower in winter vs. summer. ES and UVRd positively correlated with 25OHD only in winter in both men and women. DCI was lower than recommended and did not correlate with 25OHD levels.

Climate change and human skin cancer.

As part of an inventory of potential interactions between effects of ozone depletion and climate change, a possible effect of ambient temperature on sun-induced skin cancers was suggested. Mouse experiments had shown that increased room temperature enhanced ultraviolet (UV) radiation-induced carcinogenesis; the effective UV dose was increased by 3-7% per degrees C. The present investigation was aimed at studying a possible temperature effect on human skin cancer. Existing data on the incidence of human skin cancer were analyzed, as available from two special surveys of non-melanoma skin cancer in the United States. The incidence of non-melanoma skin cancer in the ten regions surveyed not only correlated significantly with the ambient UV dose but also with the average daily maximum temperature in summer. For squamous cell carcinoma the incidence was higher by 5.5% (SE 1.6%) per degrees C and for basal cell carcinoma by 2.9% (SE 1.4%) per degrees C. These values correspond to an increase of the effective UV dose by about 2% per degrees C. Although the precise nature of this correlation with temperature requires further studies, it can be concluded that the temperature rises coming with climate change can indeed amplify the induction of non-melanoma skin cancers by UV radiation in human populations.

Sensitivity of biologically active UV radiation to stratospheric ozone changes: effects of action spectrum shape and wavelength ranges.

Biological action spectra are commonly used to assess health and ecosystem responses to increases in spectral ultraviolet (UV) irradiances resulting from stratospheric ozone (O3) reductions. For each action spectrum, a normalized sensitivity coefficient (the radiation amplification factor [RAF]) can be calculated as the relative increase in biologically active UV irradiance for a given relative decrease in the atmospheric O3 column amount. We use a detailed radiative transfer model to calculate the dependence of RAF on the O3 column amount and the solar zenith angle (and, therefore, implicitly on latitude and season) for several commonly used action spectra. A simple analytical model is used to interpret the results in terms of the semilogarithmic slope of the action spectra in the UV-B and UV-A wavelength ranges. We also show that RAF may be overestimated substantially if the UV-A portion of an action spectrum is significant but is neglected. This is illustrated using several idealized action spectra as well as published action spectra for plant responses to UV irradiation. Generally, if the portion of an action spectrum measured longward of approximately 300 nm spans less than about two orders in magnitude in its sensitivity, significant errors in the estimated RAF may ensue, and the use of this action spectrum in O3-related studies can be compromised.

Solar UVB and plant damage irradiances for different Argentinean regions.

We calculated the integrated UVB and plant damage irradiances for Argentina, a country in the Southern Hemisphere spread over a large latitudinal range. The irradiances were calculated for clear sky days using the Madronich code for the average conditions of the months corresponding to the summer and winter solstices and the fall and spring equinoxes. Ozone, aerosol and ground albedo typical for each region and for each period of the year have been considered. A comparison was made of the behavior of these irradiances at the different locations. A more pronounced time dependence of the plant damage irradiance was obtained because of the fact that the corresponding spectrum is largely concentrated at a small wavelength of the UVB interval. We established a correlation between both irradiances, which can be approximated by a quadratic function. Because the plant damage irradiance is a quantity that is not directly measured by instruments, we showed the utility of the correlation by determining this biological effectiveness from the integrated UVB irradiance measured at the Astronomical Observatory of Rosario, Argentina, on clear sky days of the year 2001, as a characteristic example of the midlatitude near-sea level location of a highly productive agricultural region, which can be extended to other regions of the world. The plant damage results are relative ones (as is the case for the erythemal irradiance). So, they can be used to determine the maximum/minimum and asymmetry ratios, to study the influence of atmospheric variables and to make comparisons with other geographical locations.

Calibration and uncertainty estimation of erythemal radiometers in the argentine ultraviolet monitoring network.

The erythemal radiometers of the Ultraviolet Monitoring Network of the Argentine Servicio Meteorológico Nacional were calibrated in an extensive in situ campaign from October 1998 to April 1999 with Austrian reference instruments. Methods to correct the influence of the location's horizon and long-term detector changes are applied. The different terms that contribute to the measurement uncertainty are analyzed. The expanded uncertainty is estimated to be +/- 10% at 70 degrees solar zenith angle (SZA) and +/-6% for a SZA of <50 degrees. We observed significant changes for some detectors over hours and days, reaching a maximum diurnal drift of +/-5% at a SZA of 70 degrees and a maximum weekly variation of +/-4%.