4-hours resolution data to study PM10 in a “hot spot” area in Europe

Nowadays, high-time resolved aerosol studies are mandatory to better understand atmospheric processes, such as formation, removal, transport, deposition or chemical reactions. This work focuses on PM10 physical and chemical characterisation with high-time resolution: elements (from Na to Pb), ions and OC/EC fractions concentration were determined during two weeks in summer and two in winter 2006 with 4-hours resolution. Further measurements aimed at hourly elemental characterisation of fine and coarse fractions and at the determination of particles number concentration in the 0.25-32 microm size range in 31 bins. The chemical mass closure was carried out in both seasons, enhancing intra-day differences in PM10 composition. In Milan, the highest contribution came from organic matter (34% and 33% in summer and winter, respectively); other important contributors were secondary inorganic compounds (16% and 24% in summer and winter, respectively) and, in summer, crustal matter (14%). Temporal trends showed strong variations in PM10 composition during contiguous time-slots and diurnal variations in different components contribution were identified. Moreover, peculiar phenomena, which would have hardly been detected with 24-hours samplings, were evidenced. Particles removal due to precipitations, aerosol local production and long range transport were studied in detail.     

Arsenic concentration and speciation of the marine hyperaccumulator whelk Buccinum undatum collected in coastal waters of Northern Britain

European whelks (Buccinum undatum) have shown to accumulate high levels of arsenic. Since the accumulation process is not well understood it is necessary to gain information about the geographical variability of the arsenic concentration in them. Here we show that the mean arsenic concentrations of the whelks are site specific and vary by a factor of 3.5 in ten different geographical locations. At fishing grounds where whelks exhibited low arsenic concentrations the arsenic concentration increased linearly with size, whereas the whelks with high arsenic levels from a different location showed no correlation. Although the overall arsenic concentration in the whelks differed between 45 and 655 mg kg(-1) d.w., the inorganic arsenic concentration did not exceed 0.4 mg kg(-1) d.w. The main arsenic compound is arsenobetaine, which is widely considered as non-toxic. The exposure to toxic inorganic arsenic when eating whelks cannot be estimated from their size or their total arsenic concentration.     

Loggerhead turtle (<Emphasis Type="Italic">Caretta caretta</Emphasis>) matrilines in the Mediterranean: further evidence of genetic diversity and connectivity

We re-sequenced 815 bp of the mtDNA of loggerhead turtles from a population nesting in Calabria (southern Italy), which was found recently. Non-invasive sampling was applied and information on deposition date and place was used to avoid possible resampling of nesting females. Among 38 nests laid by independent females, we found the common haplotype CC-A2.1 (57.9%) and two other haplotypes which have never been described in Mediterranean nesting grounds, CC-A20.1 (36.8%) and CC-A31.1 (5.3%). Calabria harbors the highest intra-population diversity among 11 Mediterranean nesting populations. Our findings narrow the gap between haplotypes recorded in feeding grounds and those found in nesting grounds. Analyses of population structure show a strong maternal isolation, with Calabria and east Turkey displaying far more diversity than expected considering their census size. These observations suggest that recurrent female founder effects from sources yet to be identified in the Atlantic or in the Mediterranean may have shaped the pattern of mtDNA diversity in this latter basin. Our results provide evidence that the Ionian Calabrian sites should be protected because of the high diversity found there. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Regional risk assessment for contaminated sites part 2: ranking of potentially contaminated sites

Environmental risks are traditionally assessed and presented in non spatial ways although the heterogeneity of the contaminants spatial distributions, the spatial positions and relations between receptors and stressors, as well as the spatial distribution of the variables involved in the risk assessment, strongly influence exposure estimations and hence risks. Taking into account spatial variability is increasingly being recognized as a further and essential step in sound exposure and risk assessment. To address this issue an innovative methodology which integrates spatial analysis and a relative risk approach was developed. The purpose of this methodology is to prioritize sites at regional scale where a preliminary site investigation may be required. The methodology aimed at supporting the inventory of contaminated sites was implemented within the spatial decision support sYstem for Regional rIsk Assessment of DEgraded land, SYRIADE, and was applied to the case-study of the Upper Silesia region (Poland). The developed methodology and tool are both flexible and easy to adapt to different regional contexts, allowing the user to introduce the regional relevant parameters identified on the basis of user expertise and regional data availability. Moreover, the used GIS functionalities, integrated with mathematical approaches, allow to take into consideration, all at once, the multiplicity of sources and impacted receptors within the region of concern, to assess the risks posed by all contaminated sites in the region and, finally, to provide a risk-based ranking of the potentially contaminated sites.     

Seasonal and spatial variability of polychlorinated biphenyls (PCBs) in vegetation and cow milk from a high altitude pasture in the Italian Alps

The seasonal and spatial variability of polychlorinated biphenyls (PCBs) in vegetation and cow milk was studied in a high altitude pasture in the Alps (1900 m a.s.l.). PCB contamination in vegetation shows a concentration peak in June, which is mainly interpreted as the consequence of a temporary PCB enrichment of the air layer above the ground due to net emission fluxes from the soil. A three compartment dynamic model was developed to test this hypothesis. The North/South enrichment factor in the vegetation was 1.5-1.6 for penta- and hexa-substituted congeners and 1.7 for hepta- and octa-PCBs, according to the effect of temperature on compounds having higher K_oa values. Milk concentrations followed the vegetation seasonal trend. The congener abundance in milk is in agreement with the biotransformation susceptibility, absorption efficiency and residence time of the different congeners in dairy cows.     

Implications of Rural–Urban Migration for Conservation of the Atlantic Forest and Urban Growth in Misiones,Argentina (1970–2030)

Global trends of increasing rural–urban migration and population urbanization could provide opportunities for nature conservation, particularly in regions where deforestation is driven by subsistence agriculture. We analyzed the role of rural population as a driver of deforestation and its contribution to urban population growth from 1970 to the present in the Atlantic Forest of Argentina, a global conservation priority. We created future land-use-cover scenarios based on human demographic parameters and the relationship between rural population and land-cover change between 1970 and 2006. In 2006, native forest covered 50% of the province, but by 2030 all scenarios predicted a decrease that ranged from 18 to 39% forest cover. Between 1970 and 2001, rural migrants represented 20% of urban population growth and are expected to represent less than 10% by 2030. This modeling approach shows how rural–urban migration and land-use planning can favor nature conservation with little impact on urban areas.     

Historical record of mercury contamination in sediments from the Babeni Reservoir in the Olt River,Romania

Background, aim and scope

Mercury (Hg) is a ubiquitous and hazardous contaminant in the aquatic environment showing a strong biomagnification effect along the food chain. The most common transfer path of Hg to humans is contaminated fish consumption. In severely exposed humans, Hg poisoning may lead to damage in the central nervous system. Thus, it is important to examine current and past contamination levels of Hg in aquatic milieu. The Olt River is the largest Romanian tributary of the Danube River. The use of Hg as an electrode in a chlor-alkali plant contributed to the contamination of the aquatic environment in the Rm Valcea region. The purpose of this study was to compare the current state of Hg contamination with the past contamination using a historical record obtained from a dated sediment core from one of the Olt River reservoirs (Babeni) located downstream from the chlor-alkali plant. To our knowledge, no published data on Hg contamination in this region are available. The Babeni Reservoir was selected for this study because it is situated downstream from the chlor-alkali plant, whilst the other reservoirs only retain the pollutants coming from the upstream part of the watershed. Preliminary analyses (unpublished) showed high Hg concentrations in the surface sediment of the Babeni Reservoir. One core was taken in the upstream Valcea Reservoir to provide a local background level of Hg concentrations in sediments.

Results and discussion

Sediment texture was uniform in the cores from both reservoirs. Laminated sediment structure, without any obvious discontinuities, was observed. Hg concentrations in the sediment core from the Valcea Reservoir were low and constant (0.01–0.08 mg/kg). In Babeni Reservoir sediments, Hg concentrations were very high in the deeper core section (up to 45 mg/kg in the longest core) and decreased to lower concentrations toward the top of the cores (1.3–2.4 mg/kg). This decrease probably reflects technological progress in control of emissions from the Hg-cell-based chlor-alkali industry. Two strong peaks could be distinguished in older sediments. The mean rate of sedimentation (5.9 cm/year) was calculated from the depth of the ¹³⁷Cs Chernobyl peak. This was in good agreement with the sedimentation rate estimated at this site from a bathymetric study. Assuming a constant sedimentation rate, the two Hg peaks would reflect two contamination events in 1987 and 1991, respectively. However, it is also possible that the two peaks belong to the same contamination event in 1987 but were separated by a sediment layer richer in sand and silt. This layer had a low Hg concentration, which can be interpreted as a mass deposition event related to a major flood bringing Hg-free sediments.

Conclusions

Whilst the chlor-alkali plant partly switched to a cleaner technology in 1999, no obvious decrease of Hg concentrations was observed in recent decade. Results from the sediment core reflected the historical trend of Hg release from the chlor-alkali plant, revealed important contamination episodes and confirmed a legacy of contamination of Hg in recent sediments even if the concentrations of Hg decreased toward the surface due to a more efficient emission control.

Recommendations and perspectives

Although the Hg concentrations in Babeni Reservoir sediments were extremely high in the late eighties and they remain one order of magnitude higher in the surface sediments than in sediments from the upstream reservoir, little is known about the transfer of Hg to the biota and human population. Our initial measurements indicate the presence of monomethyl-Hg (MMHg) in pore water, but further studies are necessary to evaluate fluxes of MMHg at the sediment–water interface. Samples of fish and hair from various groups of the local population were recently collected to evaluate the potential hazard of Hg contamination to human health in the Rm Valcea region.

     

Historical record of mercury contamination in sediments from the Babeni Reservoir in the Olt River, Romania

Background, aim and scope  

Mercury (Hg) is a ubiquitous and hazardous contaminant in the aquatic environment showing a strong biomagnification effect along the food chain. The most common transfer path of Hg to humans is contaminated fish consumption. In severely exposed humans, Hg poisoning may lead to damage in the central nervous system. Thus, it is important to examine current and past contamination levels of Hg in aquatic milieu. The Olt River is the largest Romanian tributary of the Danube River. The use of Hg as an electrode in a chlor-alkali plant contributed to the contamination of the aquatic environment in the Rm Valcea region. The purpose of this study was to compare the current state of Hg contamination with the past contamination using a historical record obtained from a dated sediment core from one of the Olt River reservoirs (Babeni) located downstream from the chlor-alkali plant. To our knowledge, no published data on Hg contamination in this region are available. The Babeni Reservoir was selected for this study because it is situated downstream from the chlor-alkali plant, whilst the other reservoirs only retain the pollutants coming from the upstream part of the watershed. Preliminary analyses (unpublished) showed high Hg concentrations in the surface sediment of the Babeni Reservoir. One core was taken in the upstream Valcea Reservoir to provide a local background level of Hg concentrations in sediments.     

Desalinated versus recycled water: public perceptions and profiles of the accepters

Many countries' water resources are limited in both quantity and quality. While engineering solutions can now safely produce recycled and desalinated water from non-potable sources at a relatively low cost, the general public is sceptical about adopting these alternative water sources. Social scientists, policy makers and technical experts need to better understand what is causing this lack of acceptance by the general population and how acceptance levels for recycled and desalinated water can be increased. This study is the first to conduct a comparative analysis of knowledge, perceptions, and acceptability, and determine segments of residents who are more open-minded than the general population toward the use of recycled and desalinated water. The Australian population once perceived desalinated water as environmentally unfriendly, and recycled water as a public health hazard. The general level of knowledge about these two concepts as potential water sources has historically been low. After nearly five years of serious drought, accompanied by severe water restrictions across most of the country, and subsequent media attention on solutions to water scarcity, Australians now show more acceptance of desalinated water for close-to-body uses, and less resistance to recycled water for garden watering and cleaning uses. The types of people likely to be strong accepters of the two alternative water sources are distinctly different groups, and can be reached through different media mixes. This finding has significant implications for policy makers and water practitioners.     

The valuation of historical sites: a case study of Valdivia,Chile

The economic valuation of cultural heritage is an area of increasing interest and an important research topic in the emerging field of cultural economics. Many services and values associated with cultural heritage are not traded in markets, and their estimation requires methods developed for the valuation of non-market goods, such as those used in environmental economics. This paper applies the contingent valuation method with double dichotomous choice to estimate the value of historical sites in the city of Valdivia, Chile. The valuation exercise was implemented by designing a hypothetical guided walking tour to a cluster of historical sites in the city centre, and surveying tourists visiting the city during the summer of 2004. Parametric and non-parametric statistical methods were used to estimate the survival distribution and the mean and median estimates of the willingness-to-pay (WTP). The study emphasizes the importance of explicitly treating heterogeneous preferences and the sensitivity of the survival distribution to the estimation methods used.