Uncertainty of air pollution cost estimates: to what extent does it matter?

How large is the social cost penalty if one makes the wrong choice because of uncertainties in the estimates of the costs and benefits of environmental policy measures? For discrete choices there is no general rule other than the recommendation to always carefully compare costs and benefits when introducing policies for environmental protection. For continuous choices (e.g., the ceiling for the total emissions of a pollutant by an entire sector or region), it is instructive to look at the cost penalty as a function of the error in the incremental damage cost estimate. Using abatement cost curves for NOx, SO2, dioxins, and CO2, this paper evaluates the cost penalty for errors in the following: national emission ceilings for NOx and SO2 in each of 12 countries of Europe, an emission ceiling for dioxins in the UK, and limits for the emission of CO2 in Europe. The cost penalty turns out to be remarkably insensitive to errors. An error by a factor of 3 due to uncertainties in the damage estimates for NOx and SO2 increases the total social cost by at most 20% and in most cases much less. For dioxins, the total social cost is increased by at most 10%. For CO2, several different possible cost curves are examined: for some the sensitivity to uncertainties is greater than for the other pollutants, but even here the penalty is less than 30% and in most cases much less if the true damage costs are twice as high as the ones estimated. The paper also quantifies the benefit of improving the accuracy of damage cost estimates by further research.     

Electric power deregulation: will it mean dirtier air?

When U.S. utility restructuring arrives, it may bring more polluting power production, critics say.     

Does a two-year period of orthokeratology lead to changes in the endothelial morphology of children?

Purpose

To compare changes in endothelial morphology in the central and superior cornea in subjects wearing single-vision spectacles and orthokeratology lenses over two years.

Brominated dibenzo-p-dioxins: a new class of marine toxins?

Levels of polybrominated dibenzo-p-dioxins (PBDDs) were measured in marine fish, mussels, and shellfish. PBDDs were nondetectable in samples from freshwater environments, and their levels were successively higher in samples from the marine environments of the Bothnian Bay and Bothnian Sea, the West Coast of Sweden, and the Baltic Proper. In Baltic Proper littoral fish the levels of PBDDs generally exceeded those of their chlorinated analogues (PCDDs). This is alarming as some Baltic fish species already are contaminated by chlorinated dioxins to such an extent that they cannot be sold on the European market. By comparing spatial trends in PBDD and PCDD distributions, and PBDD patterns in fish, mussels, and algae, we show that the PBDDs are probably produced naturally, and we propose a route for their biosynthesis. We further show that the levels of PBDDs are high (ng/g wet weight) in mussels, and that the levels increase over time. Finally, we discuss the possibility that the PBDDs have adverse biological effects, and that the levels are increasing as a result of global warming and eutrophication.     

Development of new probiotics by strain combinations: is it possible to improve the adhesion to intestinal mucus?

We evaluated the ability of commercial probiotic strains (Lactobacillus rhamnosus GG, L. rhamnosus LC705, Bifidobacterium breve 99, and Propionibacterium freudenreichii ssp. shermanii JS) to adhere alone or in different combinations to immobilized mucus. Probiotic combinations were clearly able to enhance the adhesion of L. rhamnosus GG, L. rhamnosus LC705, and P. freudenreichii ssp. shermanii JS. For L. rhamnosus GG and P. freudenreichii JS, all the combinations significantly improved adhesion to intestinal mucus, from 29.7 to 34.9% and from 1.9 to 2.3%, respectively. The adhesion of L. rhamnosus LC705 was improved from 0 to 46.4%. The adhesion of B. breve 99 was improved only in combination with L. rhamnosus GG and P. freudenreichii JS. Our results suggest that probiotic combinations could increase the beneficial health effects as compared with individual strains. Combinations of probiotic strains may therefore have synergistic adhesion effects, and such combinations also should be assessed in clinical studies.     

Would repeated consumption of sports drinks with different acidulants lead to hedonic adjustment?

Repeated exposure to sports drinks with different acidulants added at equal sour concentrations led to hedonic adjustment when consumers (n = 128) evaluated a Lemon & Lime flavoured sports drink over a period of 14 days. Consumer preferences after repeated exposure could not have been predicted from the initial small sample single exposure consumer taste test. Product exposure and time on trial influenced the preferences of consumers. Products that were initially preferred became less preferred after 14 days. The findings of this study challenge the validity of sensory evaluation test strategies that rely on single exposure testing to predict long term consumer preferences.     

Selenium toxicity to invertebrates: will proposed thresholds for toxicity to fish and birds also protect their prey?

Efforts to manage the environmental risks of selenium (Se) in freshwater ecosystems have focused primarily on fish and birds, with invertebrates most often considered only as dietary sources of Se to higher trophic levels. Relatively little attention has been given to the risk of Se toxicity to invertebrates. Based on a review of 156 aqueous, dietary, or internal Se concentrations associated with toxic effects in 29 macroinvertebrate species, we found that water concentrations associated with acute lethality varied > 1000-fold among taxa, whereas toxic dietary concentrations varied approximately 100-fold and toxic internal concentrations varied about 30-fold. Sublethal effects occurred at approximately 10-fold lower concentrations than lethality. Sublethal effects occurred at 1-30 microg Se/g dry weight in invertebrate tissue, a range that encompasses proposed dietary thresholds for toxicity to fish and water birds, suggesting that Se may cause toxic effects in some invertebrate species at concentrations considered to be "safe" for the organisms consuming them.     

Does the product test really make a difference? Evidence from the launch of a new wine

Although both the concept and the product tests are considered important in predicting the acceptance of new food products into the market, there is scant research in the relevant literature comparing the predictive power of both tests, simultaneously, for the same product. To shed light on this line of research, this study compares the explanatory capacities of concept and product testing in the introduction of a new wine. To achieve this, a structural equation model, integrating sensory benefits, social norms and emotional dimensions with two consumer samples (one for the concept testing and another for the product testing) was proposed and tested. The results obtained showed that the modeĺs explanatory capacity did not increase significantly when the new wine was tested (product testing) in comparison to when only information about the wine was presented (concept testing). In both cases, the variables that explain purchase intention are the same. These results have important practical implications and open new research lines that can contribute to the theories that try to explain the acceptance of new foods.     

Vulnerability of water distribution systems to pathogen intrusion: how effective is a disinfectant residual?

Can the spread of infectious disease through water distribution systems be halted by a disinfectant residual? This question is overdue for an answer. Regulatory agencies and water utilities have long been concerned about accidental intrusions of pathogens into distribution system pipelines (i.e., cross-connections) and are increasingly concerned about deliberate pathogen contamination. Here, a simulation framework is developed and used to assess the vulnerability of a water system to microbiological contamination. The risk of delivering contaminated water to consumers is quantified by a network water quality model that includes disinfectant decay and disinfection kinetics. The framework is applied to two example networks under a worst-case deliberate intrusion scenario. Results show that the risk of consumer exposure is affected by the residual maintenance strategy employed. The common regulation that demands a "detectable" disinfectant residual may not provide effective consumer protection against microbial contamination. A chloramine residual, instead of free chlorine, may significantly weaken this final barrier against pathogen intrusions. Moreover, the addition of a booster station at storage tanks may improve consumer protection without requiring excessive disinfectant.     

Polyphenols in chocolate: is there a contribution to human health?

Recently, polyphenols have gained much more attention, owing to their antioxidant capacity (free radical scavenging and metal chelating) and their possible beneficial implications in human health, such as in the treatment and prevention of cancer, cardiovascular disease, and other pathologies. Cocoa is rich in polyphenols particularly in catechins (flavan-3-ols) and procyanidins. Polyphenol contents of cocoa products such as dark chocolate, milk chocolate and cocoa powder have been published only recently. However, the data vary remarkably due to the quantity of cocoa liquor used in the recipe of the cocoa products but also due to the analytical procedure employed. For example, results obtained by a colourimetric method were 5–7 times higher for the same type of product than results obtained by high performance liquid chromatography (HPLC). In 1994, the per head consumption of chocolate and chocolate confectionery in the European Union ranged from 1.3 kg/year in Portugal to 8.8 kg/year in Germany. In general, consumers in the Northern countries consume on average more than people in the South. Thus, chocolate can be seen as a relevant source for phenolic antioxidants for some European population. However, this alone does not imply, that chocolate could be beneficial to human health. Some epidemiological evidence suggests a beneficial effect to human health by following a polyphenol-rich diet, namely rich in fruits and vegetables and to a less obvious extent an intake of tea and wine having a similar polyphenol composition as cocoa. In many experiments cellular targets have been identified and molecular mechanisms of disease prevention proposed, in particular for the prevention of cancer and cardiovascular diseases as well as for alleviating the response to inflammation reactions. However, it has to be demonstrated, whether polyphenols exert these effects in vivo. One pre-requisite is that the polyphenols are absorbed from the diet. For monomeric flavonoids such as the catechins, there is increasing evidence for their absorption. For complex phenols and tannins (procyanidins) these questions have to be addressed for the future. Some indication for the absorption of procyanidins derive from studies with the human colon cancer cell line Caco-2, believed to be a valuable model for passive intestinal absorption as proposed for polyphenols. However, it has to be clarified which concentration is effective and what concentrations can be expected from food intake. Another open question is related to polyphenol metabolism. For example, much effort has been invested to show antioxidative effects of free unbound polyphenols, especially of catechins and the flavonol quercetin. However, only a very small part can be found in plasma in the free form but conjugated or even metabolised to several phenolic acids and other ring scission products. From the papers reviewed, it is as yet to early to give an answer to the question, whether chocolate and/or other sources rich in catechins and procyanidins are beneficial to human health. Even though some data are promising and justify further research in the field, it has to be shown in future, whether the intake of these functional compounds and/or their sources is related to measurable effects on human health and/or the development of diseases.     

How green is a chemical reaction? Application of LCA to green chemistry

In the present work Life Cycle Assessment (LCA) is used in order to evaluate a chemical reaction from an environmental point of view. The objective is to assess the usefulness of this methodology as an environmental tool to be applied to green chemistry. As an example, two routes of obtaining maleic anhydride are compared using LCA, to ascertain which one is the most environmentally friendly. From the results obtained in this work it can be concluded that LCA seems to be a valuable tool for the environmental assessment of a chemical reaction, because it takes into account all the life cycle stages of the process and discusses the impact of the environmental burdens inventoried according to a diversity of impact categories.