Early stage of weathering of medieval-like potash–lime model glass: evaluation of key factors

Purpose  

Throughout history, a consequent part of the medieval stained glass windows have been lost, mostly because of deliberate or accidental mechanic destruction during war or revolution, but, in some cases, did not withstand the test of time simply because of their low durability. Indeed, the glasses that remain nowadays are for many in a poor state of conservation and are heavily deteriorated. Under general exposure conditions, stained glass windows undergo different kinds of weathering processes that modify their optical properties, chemistry, and structure: congruent dissolution, leaching, and particle deposition (the combination of those two leading together to the formation of neocrystallisations and eventually crusts). Previous research has studied the weathering forms and the mechanisms from which they are originated, some others identified the main environmental parameters responsible for the deterioration and highlighted that both intrinsic (glass composition) and extrinsic (environmental parameters) factors influence glass degradation. Nevertheless, a clear quantification of the impact of the different deterioration extrinsic factors has not been performed.     

Utilizing a 'systems' approach to improve the management of waste from healthcare facilities: best practice case studies from England and Wales.

Changes in environmental legislation and standards governing healthcare waste, such as the Hazardous Waste Regulations are expected to have a significant impact on healthcare waste quantities and costs in England and Wales. This paper presents findings from two award winning case study organizations, the Cardiff and Vale NHS Trust and the Cornwall NHS Trust on 'systems' they have employed for minimizing waste. The results suggest the need for the development and implementation of a holistic range of systems in order to develop best practice, including waste minimization strategies, key performance indicators, and staff training and awareness. The implications for the sharing of best practice from the two case studies are also discussed.     

Organochlorine pesticides and polychlorinated biphenyls in soil and water samples in the Northeastern part of São Paulo State, Brazil

Detailed analyses of persistent organic pollutants (POPs) such as organochlorine pesticides (OCPs), hexachlorocyclohexane (HCH) isomers (HCHs), dichlorodiphenyltrichloro ethane (DDT) and its metabolites (DDTs) and congeners of polychlorinated biphenyls (PCBs) in soil and surface water from the northeastern São Paulo, Brazil allowed the evaluation of the contamination status, distribution and possible pollution sources. The pesticides and PCBs demonstrated markedly different distributions, reflecting different agricultural, domestic and industrial usage in each region studied. The ranges of HCH, DDT, and PCBs concentrations in the soil samples were 0.05–0.92, 0.12–11.01, 0.02–0.25 ng g⁻¹ dry wt, respectively, and in the surface water samples were 0.02–0.6, 0.02–0.58 and 0.02–0.5 ng l⁻¹, respectively. Overall elevated levels of DDT and PCB were recorded in region 2, a site very close to melting, automotive batteries industries, and agricultural practice regions. High ratios of metabolites of DDT to DDT isomers revealed the recent use of DDT in this environment. The sources of contamination are closely related to human activities, such as domestic and industrial discharge, street runoff, agricultural pesticides and soil erosion, due to deforestation as well as atmospheric transport.     

Mercury distribution in abiotic and biological compartments within several estuarine systems from Argentina: 1980-2005 period

Total mercury contents from both abiotic and biological compartments within several estuaries from Argentina have been studied since the 1980s. The assessment of mercury occurrence in surface sediments, suspended particulate matter and crab and fish species from Mar Chiquita coastal lagoon, Bahía Blanca estuary and Samborombón Bay (in La Plata river estuary) are included in the present study. All samples were analyzed through Cold Vapor-Atomic Absorption Spectroscopy, following internationally standardized methods. In all cases analytical quality was checked against international reference materials. During the 1980s, Hg contents in sediments and SPM, as well as in edible fish species from Bahía Blanca estuary were significantly higher (p<0.01) than those of the 1990s and 2000s, and the large industrial nucleus located in the northern margin of this estuary was elsewhere identified as the main source of this metal. A permanent monitoring program carried out in 1986 and that is being implemented up to the present has demonstrated that Hg concentration values have significantly decreased (p<0.01) compared to the values of the 1980s. Both, Mar Chiquita coastal lagoon and Samborombón Bay have intermediate mercury levels in their biological compartments. In both cases, the possible occurrence of remote sources of this metal was considered. Even though, Hg values as determined in sediments and suspended particulate matter from Samborombón Bay were the highest ones for the whole analyzed period. Both mercury bioaccumulation and biomagnification processes were evaluated in the studied estuaries, as well as the potential qualification of estuarine foodstuffs for human consumption.     

Sorption, desorption and mineralisation of the herbicides glyphosate and MCPA in samples from two Danish soil and subsurface profiles

The vertical distribution of the sorption, desorption and mineralisation of glyphosate and MCPA was examined in samples from two contrasting soil and subsurface profiles, obtained from a sandy agricultural site and a non-agricultural clay rich site. The highest mineralisation of [14C-methylen]glyphosate, with 9.3-14.7% degraded to 14CO2 within 3 months was found in the deepest sample from the clay site. In the deeper parts of the sandy profile high sorption and low desorption of glyphosate coincided with no or minor mineralisation indicating a limited glyphosate bioavailability. MCPA was readily mineralised except in the deepest samples from both sites. The highest MCPA mineralisation was detected just below the surface layers with 72% or 44% degraded to 14CO2 at the sandy or the clay sites, respectively. MCPA sorped to a minor extent in all samples and no indications of sorption-controlled mineralisation was revealed. None of the herbicides were mineralised under anoxic conditions.     

Foraging in a tidally structured environment by Red Knots (Calidris canutus): ideal, but not free

Besides the "normal" challenge of obtaining adequate intake rates in a patchy and dangerous world, shorebirds foraging in intertidal habitats face additional environmental hurdles. The tide forces them to commute between a roosting site and feeding grounds, twice a day. Moreover, because intertidal food patches are not all available at the same time, shorebirds should follow itineraries along the best patches available at a given time. Finally, shorebirds need additional energy stores in order to survive unpredictable periods of bad weather, during which food patches are covered by extreme tides. In order to model such tide-specific decisions, we applied stochastic dynamic programming in a spatially explicit context. Two assumptions were varied, leading to four models. First, birds had either perfect (ideal) or no (non-ideal) information about the intake rate at each site. Second, traveling between sites was either for free or incurred time and energy costs (non-free). Predictions were generated for three aspects of foraging: area use, foraging routines, and energy stores. In general, non-ideal foragers should feed most intensely and should maintain low energy stores. If traveling for such birds is free, they should feed at a random site; otherwise, they should feed close to their roost. Ideal foragers should concentrate their feeding around low tide (especially when free) and should maintain larger energy stores (especially when non-free). If traveling for such birds is free, they should feed at the site offering the highest intake rate; otherwise, they should trade off travel costs and intake rate. Models were parameterized for Red Knots (Calidris canutus) living in the Dutch Wadden Sea in late summer, an area for which detailed, spatially explicit data on prey densities and tidal heights are available. Observations of radio-marked knots (area use) and unmarked knots (foraging routines, energy stores) showed the closest match with the ideal/non-free model. We conclude that knots make state-dependent decisions by trading off starvation against foraging-associated risks, including predation. Presumably, knots share public information about resource quality that enables them to behave in a more or less ideal manner. We suggest that our modeling approach may be applicable in other systems where resources fluctuate in space and time.     

Amazonian forest loss and the long reach of China’s influence

This paper explores China’s role in deforestation in Latin America. Brazil’s Amazon region contains vast natural resources including land, timber, minerals and hydroelectric potential. China’s strong economy and large demands relative to domestic supplies of these resources mean that China has become Brazil’s largest trading partner, primarily for natural resources. The paper examines how China influences deforestation in Brazilian Amazonia in a variety of ways, including through the direct influence of Chinese enterprises through land purchases and other mechanisms. This paper finds that the rapid rise in exports of soy and beef products to China are two of the major drivers of Amazonian deforestation in Brazil. The paper further argues that Chinese purchases of agricultural and forest land and Chinese imports of commodities such as timber and aluminum also cause environmental impacts in Amazonia. Chinese financing and investment in Amazonian infrastructure such as railways and mineral processing facilities have additional impacts.