Life Cycle assessment of a plastic packaging recycling system

Goal, Scope and Background.  The object of the study is the Italian system of plastic packaging waste recycling, active until 2001, that collected and mechanically recycled the post-consumer PE and PET liquid containers. The phases of collection, compaction, sorting, reprocessing and refuse disposal were individually analysed and quantified in terms of energy and material consumptions as well as of emissions in the environment. The work is the result of a joint research project with the Italian Consortium for Packaging (CONAI), carried out in co-operation with the main Italian companies active in the field. The main aim was the quantification of the real advantage of plastic container recycling and the definition of criteria, at the same time environmentally compatible and economically sustainable, for their management. Main Features  For each of the unit processes, and in order to increase the data quality, all the data of interest were collected during technical visits to several selected plants active in Italy or deduced by official documents and certificate declarations of the same companies. To allow comparison of resource consumption and environmental pollution from different management scenarios producing different products, thebasket of products method was applied. Results  The results indicates that the production of 1 kg of flakes of recycled PET requires a total amount of gross energy that is in the range of between 42 and 55 MJ, depending on whether the process wastes (mainly coming from sorting and reprocessing activities) were sent or not to the energy recovery. The same quantity of virgin PET requires more than 77 MJ. The energetic (and then environmental) saving is so remarkable, even for PE, being 40–49 MJ for the recycled polymer and about 80 MJ that for the virgin polyolefin. The calculations were made with the reasonable assumption that the final utilisation can use the virgin or the recycled polymer without any difference. Conclusions and Outlook  The analysis defined and verified a suitable tool in the field, based on objective data, for comparing different coherent scenarios of waste management politics. This allows one to propose the extension of the tool under different collection schemes, as well as for different systems of packaging recycling. As an immediate consequence of the success of the present study, the joint-research programme with CONAI has been extended for another three years. The focus will be the Italian system for paper and paperboard recycling and that for all plastic packagings. In parallel, a different study has been scheduled with reference to the integrated solid waste management of the Regione Campania, the largest and most populated area in the South of Italy.     

Economic and environmental assessment of automotive plastic waste end-of-life options: Energy recovery versus chemical recycling

Most automotive plastic waste (APW) is landfilled or used in energy recovery as it is unsuitable for high-quality product mechanical recycling. Chemical recycling via pyrolysis offers a pathway toward closing the material loop by handling this heterogeneous waste and providing feedstock for producing virgin plastics. This study compares chemical recycling and energy recovery scenarios for APW regarding climate change impact and cumulative energy demand (CED), assessing potential environmental advantages. In addition, an economic assessment is conducted. In contrast to other studies, the assessments are based on pyrolysis experiments conducted with an actual waste fraction. Mass balances and product composition are reported. The experimental data is combined with literature data for up- and downstream processes for the assessment. Chemical recycling shows a lower net climate change impact (0.57 to 0.64 kg CO₂e/kg waste input) and CED (3.38 to 4.41 MJ/kg waste input) than energy recovery (climate change impact: 1.17 to 1.25 kg CO₂e/kg waste input; CED: 6.94 to 7.97 MJ/kg waste input), while energy recovery performs better economically (net processing cost of −0.05 to −0.02€/kg waste input) compared to chemical recycling (0.05 to 0.08€/kg waste input). However, chemical recycling keeps carbon in the material cycle contributing to a circular economy and reducing the dependence on fossil feedstocks. Therefore, an increasing circularity of APW through chemical recycling shows a conflict between economic and environmental objectives.     

Incorporating environmental aspects in an inventory routing problem. A case study from the petrochemical industry

Carbon emissions from transport activities in a supply chain are extensively contributing to global warming. However, the focus of literature in the field of sustainable supply chain management is mainly on production processes or network design decisions, considering transportation as a “necessary evil”. Consequently, transport activities are often accounted for in a rather simplified way in the analyses and are rarely analyzed on a high level of detail. Thereby the actual impacts transport processes have on the economic and environmental performance of a company are distorted. Our work focuses solely on the analysis of transport processes and shows the economic and environmental effects of routing decisions in a supply chain with vertical collaboration, for instance through vendor-managed inventory. We propose an Inventory Routing Model and apply it to a case study from the petrochemical industry. The outcome from this detailed transport analysis is then compared with results from former studies, where the main focus was on facility location decisions rather than on transportation decisions. The results point out the importance of detailed transport process analyses in order to get accurate results and suggest a potential for achieving pareto-improvements by reducing at the same time both costs and carbon emissions in a supply chain with vertical collaboration.     

A plastic property in the change of rat muscle potentials clarified in the presence of neostigmine: a conjecture on the recycling process of ACh]

Released acetylcholine (ACh) is rapidly hydrolyzed, and choline is recaptured and re-used as available ACh for release. This elaborated recycling process of ACh was evaluated in terms of muscle potentials evoked by a set of 10 stimuli in the presence and the absence of neostigmine using Wistar rats anesthetized with urethane. All potentials evoked by a set of 10 stimuli before the injection of neostigmine were similar in amplitude. The first potential recorded 8 min after it was as large as that before it. The second potential was greatly depressed, and others were gradually recovered to the control level. The recovery was attained in the 5th-7th potential in some rats while a slight depression of the 10th potential was still seen in other animals. This time course was a general pattern in the change of muscle potentials evoked by a set of 10 stimuli in the presence of neostigmine. When 10 stimuli were given 9 min after it, all potentials showed rather comparable amplitudes to the control level. Thus, another pattern was found. The two patterns were repeatedly observed within individuals: A striking contrast in the changing pattern was noted between successive two sets of 10 stimuli with an interval of one minute. The former set exerted an influence upon those muscle potentials evoked by the latter one beyond one minute or so, but this effect disappeared during the elapse of two minutes or more. This plastic property and other findings were discussed in conjunction with those evidences recently accumulated on the recycling process of ACh. A conjecture was made on the recycling process of ACh: The process would be activated following impulse transmission, and this activation would be maintained for one minute or so. In that sense, this process would be controlled in a 'short-term memory' manner and endocytosis of synaptic vesicles coupled with their exocytosis should be emphasized. In addition, releasable ACh would be restored during repetitive stimulation even if it was once depleted notably.     

Biological, technical and socioeconomic aspects of the fishing activity in a Brazilian estuary

Technical, biological and socioeconomic factors act as obstacles in the development of fishing activity in the Guaratuba Bay, southern Brazil. Amongst the difficulties registered, the following stand out: there was little variety of fishing gear; the purchasing power of the fishermen was low; there was a lack of regularity in the presence of the target species in the estuary; legislation restricted the use of certain gear at particular times; the size of the individual fish was small when compared to those from the continental shelf. Aquaculture could offer an alternative to the revenue of the fishermen, but cultural tradition and the lack of financial resources make it difficult to introduce aquaculture as an activity for the fishermen. The pessimism encountered in the community indicates that the future of artisanal fishing in this estuary is uncertain.     

Molecular aspects of nitrogen mobilization and recycling in trees

Plants have developed a variety of molecular strategies to use limiting nutrients with a maximum efficiency. N assimilated into biomolecules can be released in the form of ammonium by plant metabolic activities in various physiological processes such as photorespiration, the biosynthesis of phenylpropanoids or the mobilization of stored reserves. Thus, efficient reassimilation mechanisms are required to reincorporate liberated ammonium into metabolism and maintain N plant economy. Although the biochemistry and molecular biology of ammonium recycling in annual herbaceous plants has been previously reported, the recent advances in woody plants need to be reviewed. Moreover, it is important to point out that N recycling is quantitatively massive during some of these metabolic processes in trees, including seed germination, the onset of dormancy and resumption of active growth or the biosynthesis of lignin that takes place during wood formation. Therefore, woody plants constitute an excellent system as a model to study N mobilization and recycling. The aim of this paper is to provide an overview of different physiological processes in woody perennials that challenge the overall plant N economy by releasing important amounts of inorganic N in the form of ammonium.     

The role of seasonality in lettuce consumption: a case study of environmental and social aspects

Background, aim and scope  Considerable debate surrounds the assessment of the environmental impacts and the ethical justification for providing a year-round supply of fresh produce to consumers in the developed countries of northern Europe. Society is seeking environmentally sustainable supply chains which maintain the variety of fresh food on offer throughout the year. This paper compares the environmental impacts of different supply chains providing lettuce all year round to the UK and considers consumers' meanings of—and attitudes to—available options. Lettuce has been selected as a case study as its consumption has grown steadily during the last two decades and the supply chains through cold months are protected cropping in the UK and field cropping in Spain; during warm months, lettuce is sourced from field cropping in the UK. Materials and methods  Data were collected from farms supplying each of these supply chains, and life cycle assessment methodology was used to analyse a range of impacts associated with producing (from plant propagation to harvesting and post-harvest cooling) and delivering 1 kg of lettuce to a UK Regional Distribution Centre (RDC). The downstream stages (i.e. retailing, consumption and waste management) are the same regardless of the origin of the product and were omitted from the comparison. The impacts considered included potential to induce global warming and acidification as well as three inventory indicators (primary energy use, land use and water use). Qualitative data were collected in order to assess the consumer considerations of purchasing lettuce also during winter. Results  Importation of Spanish field-grown lettuce into the UK during winter produced fewer greenhouse gas (GHG) emissions than lettuce produced in UK-protected systems at that time (0.4–0.5 vs. 1.5–3.7 kg CO₂-eq/kg lettuce in RDC). Refrigerated transport to the UK was an important element of the global warming potential associated with Spanish lettuce (42.5% of emissions), whilst energy for heating dominated the results in UK-protected cultivation (84.3% of emissions). Results for acidification were more variable and no overall trends are apparent. Results from qualitative social analysis revealed complex and multidimensional meanings of freshness and suggested that the most striking seasonal variation in vegetable/salad eating was a tendency to consume more salads in the summer and more cooked vegetables in the winter, thus suggesting that in-home consumption alone cannot explain the rise in winter imports of lettuce to the UK. Discussion  UK field-grown lettuce had the lowest overall environmental impact; however, those lettuces are only available in summer, so consumers therefore need to either accept the environmental impacts associated with eating lettuce in the winter or to switch consumption to another food product in the winter. When lettuces were field-grown in Spain and then transported by road to the UK, the overall impacts were similar to the UK field lettuces. The variation within farms of the same country employing different cultivation regimes and practices was bigger than between farms of different countries. Conclusions  This paper has explored the environmental consequences of consuming lettuce year-round in the UK. Whilst recognising the small sample size, the comparative analysis of the different supply chains does suggest that seasonality can be an important variable when defining the best choice of lettuce from an environmental point of view. Recommendations and perspectives  Further studies considering more production sites and product types are required to obtain conclusions whose general validity is clear and for different types of fresh produce. A clear distinction to be made in such studies is whether crops are produced in open fields or under protection. New characterisation methods are needed for environmental impacts derived from the use of key agricultural resources such as land and water. Social studies to investigate consumer preferences and the possibility of moving to more seasonal diets should be an integral part of these studies using samples composed of both urban and rural consumers and using a mixed methodology with both quantitative and qualitative components.

A longitudinal study of environmental mycobacteria on a farm in south-west England

Soil, stream beds and cattle drinking troughs were sampled every 3 months over 3 years. More than 750 putative mycobacteria were isolated and grouped into more than 50 biotypes pending full identification. Samples from woodland and farmed land yielded fewer isolates per site compared with other terrains ( P < 0.05). Some seasonal effects were noted but the greatest difference was between years 1 and 3. This appeared not to be due to differences in temperature, rainfall or experimental procedure, but coincided with the introduction of organic farming practices. In year 3 there was a significant increase in nitrate-reducing slow growers, both pigmented ( P ≤ 0.006) and non-pigmented strains ( P ≤ 0.002), and a shift in biotypes was noted. In contrast, all fast growers declined with time, as did those slow growers unable to reduce nitrate. Changing farming practice may alter the profile of environmental mycobacteria, which has important implications for the immunological priming of humans and animals.     

An experimental study of the plastic responses of Ranunculus peltatus Schrank to four environmental parameters

The impact of four environmental parameters (water depth, type of substratum, current velocity and light intensity), on Ranunculus peltatus morphology and reproduction was tested in four 1 month semi- controlled experiments. Four development stages were underlined from April to August 2001 in R. peltatus: an elongation stage (April–June), a flowering stage (May–June), a fragmentation stage (June–July) and a potential regenerative stage (July–August). Water depth was therefore tested on R. peltatus elongation, type of substratum on R. peltatus elongation and flowering, current velocity on R. peltatus fragmentation and light intensity on its possible regeneration. The maximum development was measured for a 32 cm water depth. Current velocity did not have a significant effect on R. peltatus fragmentation. Regeneration depended strongly on light availability. This stage occurred only for unshaded or 50% shaded plants. Darkness prevented plants from regrowing.     

A physiological model to study iron recycling in macrophages

Following erythrophagocytosis (EP) of senescent red blood cells (RBCs), heme iron is recycled to the plasma by tissue macrophages. This process is critical for mammalian iron homeostasis but remains elusive. We characterized a cellular model using artificially-aged murine RBCs and murine bone marrow-derived macrophages (BMDMs) and study mRNA and protein expression of HO-1, ferroportin and ferritin after EP. In vitro ageing of RBCs was obtained by raising intracellular calcium concentration. These RBCs exhibit several features of erythrocyte senescence including externalization of phosphatidyl-serine, specific binding and phagocytosis by BMDMs. During the first hours of EP, we observed a rapid increase of HO-1 and ferroportin mRNAs and proteins, whereas ferritin protein expression was progressively induced with no major changes in RNA levels. At later stages after EP, a different pattern of expression was observed with a net decrease of ferroportin, a sustained high level of HO-1, and a strong increase in ferritins. Taken together, these results suggest that after EP, iron is rapidly extracted from heme and exported by ferroportin. Surprisingly, the gene expression profile at late stages after EP, which is indicative of iron storage, is reminiscent of what is observed in inflammation. However, phagocytosis of artificially-aged red blood cells seems to repress the proinflammatory response of macrophages.     

A long term study of small mammal populations in a Brazilian agricultural landscape

Long-term monitoring of small mammal populations is very important to understand the variations in temporal abundance on a large time scale, which are related to ecological, economic and epidemiological phenomena. The aim of this study is to monitor the populations of the marsupials Didelphis aurita and Philander frenatus and the rodents Nectomys squamipes, Akodon cursor and Oligorysomys nigripes in a locality of typical Brazilian rural landscape, Sumidouro Municipality, Rio de Janeiro State, Brazil. A mark-recapture study was conducted during five years. We analyzed the population dynamics, the reproduction and age structure of these species. Both marsupials presented higher population sizes in the end of wet period and beginning of the dry period, which can be explained by the seasonal reproduction which begins in the middle of the dry period and ends in the last months of the wet period. N. squamipes reproduced throughout the year but mostly during rainy periods, due to the close association of this rodent to resources found in the water. Higher survivorship and recruitment rates were in the end of the wet season. The rodent A. cursor had an opportunist reproduction, resulting in high turnover rates. Survivorship increased with the effects of the dry periods. O. nigripes showed a clear annual pattern of population cycle with peaks during the dry season. The rodents did not show potential to present outbreaks and become agricultural pests. The annual population cycles of O. nigripes and the unique peak of A. cursor population during five years highlight attention to their importance as wild reservoirs of the hantavirus disease. Their ecological characteristics associated to their opportunistic behavior make these species prone to be good reservoirs of zoonoses.     

A study of infant mortality and causes of death in a rural north-east Brazilian community

In 1984 a prospective study of 1645 women and 1677 births in a rural community in north-eastern Brazil showed the infant mortality rate to be 65 per 1000 live births. Neonatal, post-neonatal and infant mortality are analysed to determine the most important risk factors for each period. Post-neonatal survival depends largely on factors relating to child care, while neonatal deaths are more likely to be associated with biological factors. The principal cause of death, diarrhoeal disease, was responsible for a third of the deaths.     

Responding to environmental change: plastic responses vary little in a synchronous breeder

The impact of environmental change on animal populations is strongly influenced by the ability of individuals to plastically adjust key life-history events. There is therefore considerable interest in establishing the degree of plasticity in traits and how selection acts on plasticity in natural populations. Breeding time is a key life-history trait that affects fitness and recent studies have found that females vary significantly in their breeding time-environment relationships, with selection often favouring individuals exhibiting stronger plastic responses. In contrast, here, we show that although breeding time in the common guillemot, Uria aalge, is highly plastic at the population level in response to a large-scale environmental cue (the North Atlantic Oscillation, NAO), there is very little between-individual variation-most individuals respond to this climate cue very similarly. We demonstrate strong stabilizing selection against individuals who deviate from the average population-level response to NAO. This species differs significantly from those previously studied in being a colonial breeder, in which reproductive synchrony has a substantial impact on fitness; we suggest that counter selection imposed by a need for synchrony could limit individuals in their response and potential for directional selection to act. This demonstrates the importance of considering the relative costs and benefits of highly plastic responses in assessing the likely response of a population to the environmental change.     

A retrospective mortality study of workers exposed to radon in a Brazilian underground coal mine

Recently a high radon concentration was detected in the underground coal mine of Figueira, located in the south of Brazil. This coal mine has been operating since 1942 without taking cognizance of the high radon environment. In order to assess possible radon-related health effects on the workers, a retrospective (1979-2002) mortality study of 2,856 Brazilian coal miners was conducted, with 2,024 underground workers potentially exposed to radon daughters. Standard mortality ratio (SMR) analysis hints at lower mortality from all causes for both underground (SMR = 88, 95% CI = 78-98) and surface workers (SMR = 96, 95% CI = 80-114). A high statistically significant SMR for lung cancer mortality was observed only in the underground miners (SMR = 173, 95% CI = 102-292), with a statistically significant trend reflecting the duration of underground work. High statistically significant SMRs were observed for pneumonia as a cause of death between both surface (SMR = 304, 95% CI = 126-730) and underground miners (SMR = 253, 95% CI = 140-457). Because mortality from smoking-related cancers other than lung cancer was not found elevated in underground workers and because diesel equipments were not used in this mine, it can be concluded that the enhanced lung cancer mortality observed for underground miners is associated with exposure to radon and radon daughters, rather than other confounding risk factors.