Issues Concerning Survival of Viruses on Surfaces

Viruses are the causative agents of an estimated 60% of human infections worldwide. The most common viral illnesses are produced by enteric and respiratory viruses. Transmission of these viruses from an infected person or animal to a new host can occur via several routes. Existing studies strongly suggest that contaminated fomites or surfaces play an important role in the spreading of viral diseases. The potential of viral spreading via contaminated surfaces depends particularly on the ability of the virus to maintain infectivity whilst it is in the environment. This is affected by a combination of biological, physical and chemical factors. This review summarises current knowledge about the influence of environmental factors on the survival and spread of viruses via contaminated surfaces.     

Effects of Bacterial, Chemical, Physical and Meteorological Variables on Virus Removal by a Wastewater Treatment Plant

The purpose of wastewater treatment is to minimize chemical and microbial contamination of recipient waters. The present study evaluated the impacts of meteorological variables, such as temperature and rainfall, on the removal of human viruses and indicators by a wastewater treatment plant servicing Pisa, Italy. Data were obtained during four sampling campaigns from 2007 to 2010. Wastewater sewage samples were analyzed for human adenovirus (HAdV) and norovirus using quantitative molecular techniques. In parallel, Escherichia coli, enterococci and somatic coliphages were measured, and meteorological and chemical data were recorded. We detected a continuous presence of HAdV in both influent and effluent samples with an average removal rate of 2.01 log₁₀ Genomic Copies/l. An association between meteorological parameters and viral removal rates was detected only for rainfall and HAdV removal during a specific sampling campaign. No correlation was found between viral data and microbial, chemical and physical ones. Viral removal rates were not strongly influenced by meteorological conditions and were unrelated to other process indicators routinely monitored. Our results suggest that HAdV is a suitable parameter to assess the viral removal efficiency of wastewater treatment plants, particularly in the case of heavy rainfall.     

Atomic absorption spectrometric determination of inorganic and organic arsenic in some marine benthic algae of the southern atlantic coasts

Arsenic in the inorganic and organic forms was analyzed in species of marine macro-algae growing in the South Atlantic Ocean. Species of the genera Lessonia, Gigartina, Adenocystis, Leathesia and Colpomenia were investigated. Arsenic accumulation was found in all species studied. Total As content ranged from 5.3 to 56.9 microg As g(-1) and the levels of the inorganic forms ranged from 0.2 to 2.0 microg As g(-1). The complete analytical procedure was validated against a standard reference material (NBS, SRM 1572, citrus leaves) and the value obtained was in good agreement with the certified value. Some commercial seaweed products were also analyzed.     

Quantification of Human Adenoviruses in European Recreational Waters

The presence of human adenoviruses (HAdV) in recreational water might cause disease in the population upon exposure. HAdV detected by PCR could also serve as indicators of the virological water quality. In order to assess the applicability of HAdV to the evaluation of the faecal contamination in European bathing waters, a real-time quantitative PCR assay was used for the quantification of HAdV in 132 samples collected from 24 different recreational marine and freshwater sites in nine European countries. Selected samples presenting positive nested PCR results for HAdV were analyzed using quantitative PCR and 80 samples from a total of 132 produced quantitative results with mean values of 3.2 × 10² per 100 ml of water, being human adenovirus 41 the most prevalent serotype between the samples where adenovirus was typified. HAdV were quantified in samples from all 15 surveillance laboratories. Statistical analysis showed no homogeneous linear relation between HAdV and E. coli, intestinal enterococci or somatic coliphages concentrations in the tested samples when considering all the data together. Significant correlations between HAdV and at least one of the other indicators were observed only when data from individual laboratories were considered. The quantification of HAdV may provide complementary information in relation to the use of bacterial standards in the control of water quality in bathing water.     

Viral Removal by Wastewater Treatment: Monitoring of Indicators and Pathogens

The discharge of treated civil wastewater into natural waters or their reuse in industry and agriculture involves virological risks for the exposed population. Although European and Italian regulations do not require routine viral analysis of treated wastewater, a better understanding of viral contamination and resistance to treatments is needed to assess and control such risks. To this end, a wastewater treatment plant was monitored by analysing the sewage at the plant entry and exit points in order to quantify the initial presence and eventual reduction of adenovirus, Torque Teno virus, Hepatitis A virus, rotavirus, enterovirus, norovirus genogroups I and II, somatic coliphages, Escherichia coli and enterococci. The results reveal that treated water may still contain infectious human viruses and thereby represent a potential health hazard. No significant correlations were found between bacterial indicators and the viruses considered, confirming their inadequacy for virological risk assessment, while the best indicators for virus inactivation in recycled waters seem to be adenovirus, followed by somatic coliphages.     

A link between lead and cadmium kinetic speciation in seawater and accumulation by the green alga Ulva lactuca

In this work, studies on the bioaccumulation of Cd and Pb by Ulva lactuca at different sites of Gulf San Jorge (Patagonia, Argentina) are presented. Higher values of bioaccumulated Cd were found in Punta Maqueda - a site believed to serve as a control - in comparison to those in Punta Borja, a place highly exposed to urban and industrial activities. Consequently; the labile fractions of Cd and Pb in seawater were determined with a flow injection-preconcentration manifold interfaced to a graphite furnace-atomic absorption spectrometer (FI-GFAAS). The results obtained by kinetic speciation showed that the variable that correctly explains heavy metals accumulation in the alga, is the labile metal fraction in seawater. We propose to use an enhancement ratio - on the basis of the kinetically labile metal fraction - for calculation of the metal accumulated by the alga relative to its environment.     

A survey of some trace elements in seaweeds from Patagonia, Argentina

Cadmium and lead concentrations were determined in some common algal species living in the southernmost coasts of Argentina. Two different sampling areas were chosen: Gulf Nuevo, a locality being influenced by a developing industrial city, and Bay Camarones, a traditional harvest area for seaweed exploitation. Selected species of the genera Lessonia, Macrocystis and Gigartina, all of commercial interest, were collected from the harvest area, and analyses showed low levels of the metals in these species. Accumulation of Pb and Cd was also evident in other common brown seaweeds from the industrial site. Analysis of Al was included in this study due to an aluminum works near one of the sampling sites. High values of this metal ranging between 300 and 3000 mg Al/kg (dry basis) were recorded in the industrialized area. Amongst all of the species studied, Colpomenia sinuosa from Gulf Nuevo exhibited the highest values of aluminum. This preliminary survey showed that, except for Al, the levels of Cd and Pb were lower than those reported in same species of seaweeds from the polluted marine waters of the rest of the world.