Biomedical subjects

Ad M J Ragas

Publications and source records attributed to Ad M J Ragas.

6 recordsLinked to original sources

PubMed2006

Is cumulative fossil energy demand a useful indicator for the environmental performance of products?

The appropriateness of the fossil Cumulative Energy Demand (CED) as an indicator for the environmental performance of products and processes is explored with a regression analysis between the environmental life-cycle impacts and fossil CEDs of 1218 products, divided into the product categories "energy production", "material production", "transport", and "waste treatment". Our results show that, for all product groups but waste treatment, the fossil CED correlates well with most impact categories, such as global warming, resource depletion, acidification, eutrophication, tropospheric ozone formation, ozone depletion, and human toxicity (explained variance between 46% and 100%). We conclude that the use of fossil fuels is an important driver of several environmental impacts and thereby indicative for many environmental problems. It maytherefore serve as a screening indicatorfor environmental performance. However, the usefulness of fossil CED as a stand-alone indicator for environmental impact is limited by the large uncertainty in the product-specific fossil CED-based impact scores (larger than a factor of 10 for the majority of the impact categories; 95% confidence interval). A major reason for this high uncertainty is nonfossil energy related emissions and land use, such as landfill leachates, radionuclide emissions, and land use in agriculture and forestry.

Agriculture↗

PubMed2006

Development and implementation of a right-to-know web site that presents estimated cancer risks for air emissions of large industrial facilities.

A publicly accessible web site was developed that provides environmental information on air emissions of local facilities in 3 regions in the Netherlands. Compared with other environmental right-to-know initiatives, the main innovative aspect of this web site is the presentation of emissions data in terms of estimated increased cancer risk. The basic idea is that this type of information will help people 1) to put the health effects of air emissions of the selected facilities into perspective and 2) to form a personal opinion about the acceptability of these risks. In the 1st 5 months, the web site was visited more than 77,000 times, with more than 33,000 visits in the 1st month (March 2004). The web site triggered a discussion on the accessibility and presentation of environmental risk information in The Netherlands, which even reached the Dutch parliament. To improve and maintain this type of right-to-know initiative, it is important that 1) responsible authorities establish and maintain a detailed and up-to-date database of national, regional, and local emissions data, 2) the initiative is implemented in a legal framework or adopted by an independent body, and 3) more knowledge becomes available about the understanding and effects of environmental risk information on the general public.

Air Pollutants↗

PubMed2005

Spatial variability and uncertainty in ecological risk assessment: a case study on the potential risk of cadmium for the little owl in a Dutch river flood plain.

This paper outlines a procedure that quantifies the impact of different sources of spatial variability and uncertainty on ecological risk estimates. The procedure is illustrated in a case study that estimates the risks of cadmium for a little owl (Athene noctua vidalli) living in a Dutch river flood plain along the river Rhine. A geographical information system (GIS) was used to quantify spatial variability in contaminant concentrations and habitats. It was combined with an exposure and effect model that uses Monte Carlo simulation to quantify parameter uncertainty. Spatial model uncertainty was assessed by the application of two different spatial interpolation methods (classification and kriging) and foraging ranges. The results of the case study show that parameter uncertainty is the main type of uncertainty influencing the risk estimate, and to a lesser extent spatial variability, while spatial model uncertainty was of minor importance. Compared to the deterministically calculated hazard index for the little owl (0.9), inclusion of spatial variability resulted in a median hazard index that can vary between 0.8 and 1.4. It is concluded that a single estimator for a whole flood plain may over- or underestimate risks for specific parts within the flood plain. Further research that expands the procedure presented in this paper is necessary to improve the incorporation of spatial factors in ecological risk assessment.

Animals↗

PubMed2005

Human-toxicological effect and damage factors of carcinogenic and noncarcinogenic chemicals for life cycle impact assessment.

Chemical fate, effect, and damage should be accounted for in the analysis of human health impacts by toxic chemicals in life-cycle assessment (LCA). The goal of this article is to present a new method to derive human damage and effect factors of toxic pollutants, starting from a lognormal dose-response function. Human damage factors are expressed as disability-adjusted life years (DALYs). Human effect factors contain a disease-specific and a substance-specific component. The disease-specific component depends on the probability of disease occurrence and the distribution of sensitivities in the human population. The substance-specific component, equal to the inverse of the ED50, represents the toxic potency of a substance. The new method has been applied to calculate combined human damage and effect factors for 1,192 substances. The total range of 7 to 9 orders of magnitude between the substances is dominated by the range in toxic potencies. For the combined factors, the typical uncertainty, represented by the square root of the ratio of the 97.5th and 2.5th percentile, is a factor of 25 for carcinogenic effects and a factor of 125 for noncarcinogenic effects. The interspecies conversion factor, the (non)cancer effect conversion factor, and the average noncancer damage factor dominate the overall uncertainty.

Animals↗

PubMed2003

Evaluating uncertainty in environmental life-cycle assessment. A case study comparing two insulation options for a Dutch one-family dwelling.

The evaluation of uncertainty is relatively new in environmental life-cycle assessment (LCA). It provides useful information to assess the reliability of LCA-based decisions and to guide future research toward reducing uncertainty. Most uncertainty studies in LCA quantify only one type of uncertainty, i.e., uncertainty due to input data (parameter uncertainty). However, LCA outcomes can also be uncertain due to normative choices (scenario uncertainty) and the mathematical models involved (model uncertainty). The present paper outlines a new methodology that quantifies parameter, scenario, and model uncertainty simultaneously in environmental life-cycle assessment. The procedure is illustrated in a case study that compares two insulation options for a Dutch one-family dwelling. Parameter uncertainty was quantified by means of Monte Carlo simulation. Scenario and model uncertainty were quantified by resampling different decision scenarios and model formulations, respectively. Although scenario and model uncertainty were not quantified comprehensively, the results indicate that both types of uncertainty influence the case study outcomes. This stresses the importance of quantifying parameter, scenario, and model uncertainty simultaneously. The two insulation options studied were found to have significantly different impact scores for global warming, stratospheric ozone depletion, and eutrophication. The thickest insulation option has the lowest impact on global warming and eutrophication, and the highest impact on stratospheric ozone depletion.

Air Pollution, Indoor↗

PubMed2003

Prediction of ecological no-effect concentrations for initial risk assessment: combining substance-specific data and database information.

A new method is proposed to derive predicted no-effect concentrations (PNECs) for initial risk assessments for aquatic ecosystems from a limited set of single-species toxicity data. The method includes three steps. First, acute toxicity data are divided by an acute-to-chronic assessment factor to obtain chronic toxicity data. Subsequently, chronic toxicity data are averaged to obtain an average hazardous concentration (HC50). Finally, the HC50 is divided by an interspecies assessment factor to obtain a PNEC. Both assessment factors are derived as probability distributions from an extensive ecotoxicological database. The interspecies assessment factor is combined with substance-specific toxicity data using Bayesian statistics. The proposed method optimizes the use of the available ecotoxicological information and it produces an uncertainty estimate of the PNEC. Sample calculations indicate that the proposed method may provide a good alternative for currently applied methods for initial risk assessment, particularly if few toxicity data are available.

Animals↗