6th SETAC-Europe Meeting: LCA - Selected Papers uses

Most former methods for the impact assessment of toxic releases in LCA gave a relative yardstick for the potential toxic effect of a substance, with no allowance being made for intermedia transport and degradation. These factors may be of major influence on the degree of (eco)toxic effects to be expected. As part of its work on substance policy, RIVM has developed a computer model calledUniform System for the Evaluation of Substances (USES) to assess, as realistically as possible, the degree to which the no-effect level is transgressed in practice. This model makes allowances for the fate of substances in the environment. An important offspring of the project is not only that substance assessment has been linked to the LCA method, but also that it shows LCA users how they can establish the LCA equivalency factors for the (eco)toxicity of “unknown” substances by themselves, and how they can recalculate the equivalency factors that were reported from the project. This last point is particularly of interest because the new list of equivalency factors suffers from serious uncertainties due to data gaps. Lastly, some future perspectives as to further modelling activities is discussed, in particular with respect to a generic fate model for all emission-related impact types.     

Evaluating Land-Use Impacts: Selection of Surface Area Metrics for Life-Cycle Assessment of Mining

Land use is an increasingly important component of sustainability evaluations, and numerous performance metrics have evolved to meet this need. The selection of appropriate land-use metrics for decision makers, however, remains an ongoing challenge. Additionally, life-cycle practitioners often struggle to provide meaningful impact assessment because of challenges associated with traditional land-use impact metrics. This article is intended to assist decision makers and life-cycle practitioners who wish to more effectively measure and evaluate one aspect of land use: surface area occupation. Existing performance metrics are discussed, and the specific circumstances under which each is appropriate are identified. Building on leading-edge research and analysis in the field of life-cycle impact assessment, a modified methodology for evaluating surface area occupation is proposed. This approach is demonstrated for a series of mining practices including three individual gold mines, a bauxite mine, and a copper mine. The specific data requirements and resulting equivalency factors for each mine are discussed. Results indicate that equivalency factors for gold (average of 700 acre-yr/ton) are expected to be several orders of magnitude higher than for either bauxite (0.004 acre-yr/ ton) or copper (0.03 acre-yr/ton). These dramatic differences in results demonstrate that equivalency factors are appropriate and necessary for including land-use impact potential as part of a life-cycle assessment that includes several different minerals or material requirements.     

Regional scaling and normalization in LCIA

Methodologies for regional scaling and normalization steps in life-cycle impact assessment (LCIA) were developed and applied to two case studies in connection with the equivalency factor type of hazard characterization approach. Regional scaling factors are numerical scores used to indicate ranges of the degree of sensitivity that a particular region has for the selected impact category. These factors were developed to modify and improve the accuracy of partial equivalency factors for five impact categories. Normalization is the process of defining the relative contribution of the characterization scores by impact category to the total impact for the same category. Normalization factors were developed that represent the total, annual, geographically relevant, impact potential (hazard potential from emission loading or resource use) for a given impact category. Global or U.S. data were obtained to develop normalization factors representing 14 impact categories considered to be relevant to three spatial areas: global, state, and facility. The regional scaling and normalization methods improved the ability to evaluate two LCIA case studies in the U.S. and increased the accuracy of conclusions about which alternative processes or individual impact categories had the greatest potential hazard for environmental effects.     

Data-Driven Method to Estimate Nonlinear Chemical Equivalence

There is great need to express the impacts of chemicals found in the environment in terms of effects from alternative chemicals of interest. Methods currently employed in fields such as life-cycle assessment, risk assessment, mixtures toxicology, and pharmacology rely mostly on heuristic arguments to justify the use of linear relationships in the construction of “equivalency factors,” which aim to model these concentration-concentration correlations. However, the use of linear models, even at low concentrations, oversimplifies the nonlinear nature of the concentration-response curve, therefore introducing error into calculations involving these factors. We address this problem by reporting a method to determine a concentration-concentration relationship between two chemicals based on the full extent of experimentally derived concentration-response curves. Although this method can be easily generalized, we develop and illustrate it from the perspective of toxicology, in which we provide equations relating the sigmoid and non-monotone, or “biphasic,” responses typical of the field. The resulting concentration-concentration relationships are manifestly nonlinear for nearly any chemical level, even at the very low concentrations common to environmental measurements. We demonstrate the method using real-world examples of toxicological data which may exhibit sigmoid and biphasic mortality curves. Finally, we use our models to calculate equivalency factors, and show that traditional results are recovered only when the concentration-response curves are “parallel,” which has been noted before, but we make formal here by providing mathematical conditions on the validity of this approach.     

The electrophoretic isolation and partial characterization of three chlorophyll-protein complexes from blue-green algae.

Three chlorophyll-protein complexes have been resolved from blue-green algae using an improved procedure for membrane solubilization and electrophoretic fractionation. One complex has a red absorbance maximum of 676 nm and a molecular weight equivalency of 255 000 +/- 15 000. A second complex has an absorbance maximum of 676 nm, a molecular weight equivalency of 118 000 +/- 8000, and resembles the previously described P-700-chlorophyll a-protein (CPI) of higher plants and algae. The third chlorophyll-protein has a red absorbance maximum of 671 nm and a molecular weight equivalency of 58 000 +/- 5000. Blue-green algal membrane fractions enriched in Photosystem I and heterocyst cells do not contain this third chlorophyll-protein, whereas Photosystem II-enriched membrane fractions and vegetative cells do. A component of the same spectral characteristics and molecular weight equivalency was also observed in chlorophyll b-deficient mutants of barley and maize. It is hypothesized that this third complex is involved in some manner with Photosystem II.     

The minimum significant ratio: a statistical parameter to characterize the reproducibility of potency estimates from concentration-response assays and estimation by replicate-experiment studies

The authors show by illustration that procedures used to validate the reliability of single-concentration high-throughput screens such as the signal window and Z' factor do not ensure sufficient reliability in potency estimates from concentration response assays. They develop the minimum significant ratio as a statistical parameter to characterize the fold change between 2 compounds run in the same experiment that can be considered a real difference and use this parameter to characterize the reliability of the assay. They adapt methods described by Bland and Altman to develop a simple set of 2 experiments to estimate the minimum significant ratio and show that this protocol can identify assays that lack reproducibility. The methods are then extended to validate the equivalency of the same assay run by multiple laboratories.     

Studies of novel bioactive substances in the spent media of cell lines using protein-free culture system]

Many human cell lines have been maintained in fetal bovine serum (FBS)-supplemented medium. These produce and secrete many substances such as transferrin, alpha 1-antitrypsin, alpha 2-macroglobulin, alkaline phosphatase, gamma-glutamyltranspeptidase, creatine kinase, carcino-embryonic antigen, alpha-fetoprotein, and cytokines including colony stimulating factors and transforming growth factors and further they may produce small amounts of unknown substances. Usually, small amounts of substances have to be concentrated as highly as possible for detection, but FBS interferes with procedures. A protein-free culture system in an ideal method for detecting small quantities of substances which originate from cell lines without interference by FBS. Our protein-free culture system can be available in every laboratory since this is not only an economical method, but also an effective method for the saving of purification procedures. Moreover, this is a most suitable method for surveying unknown substances derived from cell lines.     

A Hazard Assessment of Aggregate Exposure to Nonylphenol and Nonylphenol Mono- and Di-ethoxylates in the Aquatic Environment

The most commonly detected environmental metabolites of nonylphenol ethoxylates (NPE) are nonylphenol monoethoxylate (NPE1), nonylphenol diethoxylate (NPE2), nonylphenol ether carboxylates (NPEC), and nonylphenol (NP). Since NPEC have relatively low toxicity, the most relevant NPE metabolites for conducting an aggregate hazard assessment are NP, NPE1, and NPE2. Recent studies support the validity of the U.S. Environmental Protection Agency (2005) chronic water quality criteria (WQC) for NP in freshwater and saltwater environments; thus, these criteria were used as reference values in the aggregate hazard assessment. The toxic equivalency approach was used to assess the aggregate hazard of NP, NPE1, and NPE2. A review of relevant studies indicated that the toxic equivalency factor (TEF) for NPE1 and NPE2 approximated 0.37, which supported the use of the more conservative TEF value of 0.50 used by Environment Canada (2001) for NPE1 and NPE2. The interaction of toxicities between NP, NPE1, and NPE2 is assumed to be additive based on a review of the current literature and the shared mechanism of action of these compounds. The data support previous findings that there is a low likelihood that aggregate NP-equivalent concentrations of NPE and its metabolites in U.S. waters will exceed the national chronic WQC for NP.     

Human Health Damages due to Indoor Sources of Organic Compounds and Radioactivity in Life Cycle Impact Assessment of Dwellings - Part 1: Characterisation Factors (8 pp)

- Part 1: Characterisation factors (DOI: http://dx.doi.org/10.1065/lca2004.12.194.1) Part 2: Damage scores (DOI: http://dx.doi.org/10.1065/lca2004.12.194.2) - Preamble. In this series of two papers, a methodology to calculate damages to human health caused by indoor emissions from building materials is presented and applied. Part 1 presents the theoretical foundation of the indoor emission methodology developed, as well as characterisation factors calculated for 36 organic compounds, radon and gamma radiation. Part 2 calculates damage scores of building materials with the characterisation factors presented in part 1. The relevancy of including indoor air emission in the full damage scores at a material level and a dwelling level is also quantified and discussed. Goal, Scope and Background Methodologies based on life cycle assessment have been developed to calculate the environmental impact of dwellings. Human health damage due to exposure to substances emitted to indoor air are not included in these methodologies. In order to compare this damage with human health damages associated with the rest of the life cycle of the dwelling, a methodology has been developed to calculate damages to human health caused by pollutants emitted from building materials. Methods Fate, exposure and health effects are addressed in the calculation procedure. The methodology is suitable for organic substances, radon and elements emitting gamma radiation. The (Dutch reference) dwelling used in the calculation was divided in three compartments: crawl space, first floor and second floor. Fate factors have been calculated based on indoor and outdoor intake fractions, dose conversion factors or extrapolation from measurements. Effect factors have been calculated based on unit risk factors, (extrapolated) effect doses or linear relationship between dose and cancer cases. Damage factors are based on disability adjusted life years (DALYs). Results and Discussion Characterisation factors have been calculated for 36 organic compounds, radon and gamma radiation emitted by building materials applied in a Dutch reference dwelling. For organic compounds and radon, the characterisation factors of emissions to the second floor are 10–20% higher than the characterisation factors of emissions to the first floor. For the first and second floor, the characterisation factors are dominated by damage to human health as a result of indoor exposure. The relative contribution of carcinogenic and non-carcinogenic effects to the characterisation factors is generally within one order of magnitude, and up to three orders of magnitude for formaldehyde. Conclusion Health effects due to indoor exposure to pollutants emitted from building materials appear to be dominant in the characterisation factors over outdoor exposure to such pollutants. The health effects of emissions of organic compounds and gamma radiation in the crawl space are very small compared to the health effects of emissions into the other compartments. Using the characterisation factors calculated in this study, it is possible to calculate the human health damage due to emissions of substances and radiation emitted to indoor air and compare this damage with damages to human health associated with the rest of the life cycle of the material. This is the subject of part II of this research.     

The Effect of Sample Design in the Discriminant Analysis for Two Groups

This paper shows the effect of sample design on the Discriminant Analysis for two groups by means of a simulation study involving stratified design. Four criteria of discrimination are used and compared. Also, the equivalency between the Multiple Linear Regression using the Generalized Estimating Equations and the Discriminant Analysis for two normal populations from a Complex Design is proved. The results are applied to an epidemiological problem.     

The electrophoretic isolation and partial characterization of three chlorophyll-protein complexes from blue-green algae

Three chlorophyll-protein complexes have been resolved from blue-green algae using an improved procedure for membrane solubilization and electrophoretic fractionation. One complex has a red absorbance maximum of 676 nm and a molecular weight equivalency of 255 000 ± 15 000. A second complex has an absorbance maximum of 676 nm, a molecular weight equivalency of 118 000 ± 8000, and resembles the previously described P-700-chlorophylla-protein (CPI) of higher plants and algae. The third chlorophyll-protein has a red absorbance maximum of 671 nm and a molecular weight equivalency of 58 000 ± 5000. Blue-green algal membrane fractions enriched in Photosystem I and heterocyst cells do not contain this third chlorophyll-protein, whereas Photosystem II-enriched membrane fractions and vegetative cells do. A component of the same spectral characteristics and molecular weight equivalency was also observed in chlorophyll b-deficient mutants of barley and maize. It is hypothesized that this third complex is involved in some manner with Photosystem II.     

Isolation, composition and reactivity of the neutral glycoproteins from human meconiums with specificities of the ABO and Lewis systems.

Blood-group-specific A1, B, AB, H and Lea neutral glycoproteins were isolated from suitable pools of human normal meconiums by a preliminary fractionation with a cationic detergent at pH5 and 9 (borate), followed by ion-exchange and gel chromatography. The ABH materials have sedimentation coefficients of about 10S-11S, whereas the Lea preparation, not strictly homogeneous, shows a coefficient of 7S. From the detailed analytical data collected, the following relations are deduced between these various substances; they all possess a common peptide core; there are stable ratios of N-acetylglucosamine/N-acetylgalactosamine in the B, H and Lea materials and of N-acetylglucosamine/galactose in A, H and Lea materials, from which the numbers of A and B determinants are estimated. In the ABH substances, the ratio of glucosamine to the sum of threonine and serine is stable. Presumably because of genetic factors, the amount of fucose varies among the different glycoproteins, but it is always definitely lower than in the average cyst substances. Various serological tests and precipitin methods were used to measure the potency, purity and integrity of the preparations, including comparisons between A1 and A2 substances from this source. The Leb activity did not appear as high as it is in glycoproteins from adults and a possible interpretation would be the immature Lewis system as observed on erythrocytes; this could explain their very strong inhibiting power towards iso-agglutinins. This family of substances with various specificities has common features with that prepared from ovarian cysts, but differs clearly on some points.     

Mechanisms and rate equations for dissociating systems.

The results presented in the previous paper (Boeker, E.A. (1978), Biochemistry 17 (preceding paper in this issue) indicate that the dissociation of the decamer of arginine decarboxylase of Escherichia coli B is enhanced by Na+ and retarded by H+. In this system, substances which increase the rate of dissociation can be treated kinetically either as substrates or activators, and substances which retard dissociation can be treated as products or inhibitors. In addition, the events needed for dissociation can occur in an ordered or a random sequence, and the dissociation itself, from a decamer to five dimers, can be a sequential or a concerted process. In order to provide a framework for the experimental results, mechanisms for the dissociation of arginine decarboxylase that take all of these factors into account are described. In addition, it is shown that the usual methods of steady-state kinetics can be applied to these systems when true initial rates are measured; rate equations are presented for each mechanism. The results can be used for any dissociating of three or more subunits and will describe the dissociation of a dimer under certain conditions.     

Field Evaluation of Alternative Earthen Final Covers

Five methods to assess percolation rate from alternative earthen final covers (AEFCs) are described in the context of the precision with which the percolation rate can be estimated: trend analysis, tracer methods, water balance method, Darcy's Law calculations, and lysimetry. Trend evaluation of water content data is the least precise method because it cannot be used alone to assess the percolation rate. The precision of percolation rates estimated using tracer methods depends on the tracer concentration, percolation rate, and the sensitivity of the chemical extraction and analysis methods. Percolation rates determined using the water balance method have a precision of approximately 100 mm/yr in humid climates and 50 mm/yr in semiarid and drier climates, which is too large to demonstrate that an AEFC is meeting typical equivalency criterion (30 mm/yr or less). In most cases, the precision will be much poorer. Percolation rates computed using Darcy's Law with measured profiles of water content and matric suction typically have a precision that is about two orders of magnitude (or more) greater than the computed percolation rate. The Darcy's Law method can only be used for performance assessment if the estimated percolation rate is much smaller than the equivalency criterion and preferential flow is not present. Lysimetry provides the most precise estimates of percolation rate, but the precision depends on the method used to measure the collected water. The lysimeter used in the Alternative Cover Assessment Program (ACAP), which is described in this paper, can be used to estimate percolation rates with a precision between 0.00004 to 0.5 mm/yr, depending on the measurement method and the flow rates.     

Hemostatic mechanisms and malignant tumors

The mutual relationships between malignant tumours and mechanisms of blood coagulation are presented in a brief survey. In this connection, the mechanisms of a tumour cell entering the circulation through the vessel well and its leaving into the tissues are discussed, the theory of microtrauma being used for explaining these processes. Subsequently, the alterations to be found in the count and function of thrombocytes after contact with a malignant cell and the impact on this cell by blood platelets are represented. As a third factor the activation of blood coagulation which is exercised by substances with a procoagulatory effect produced by the malignant tissue and the frequently observed thrombosis in the course of neoplastic diseases are dealt with in connection with blood level changes of some coagulation factors. In a fourth section the significance of fibrinolysis, its activation and inhibition as well as the production of fibrinolytic activators by neoplasms are discussed.     

Improving odour assessment in LCA—the odour footprint

Purpose

Odour is an important aspect of systems for human and agricultural waste management and many technologies are developed with the sole purpose of reducing odour. Compared with greenhouse gas assessment and the assessment of toxicity, odour assessment has received little attention in the life cycle assessment (LCA) community. This article aims to redress this.

Methods

Firstly, a framework for the assessment of odour impacts in LCA was developed considering the classical LCA framework of emissions, midpoint and endpoint indicators. This suggested that an odour footprint midpoint indicator was worth striving for. An approach to calculating an areal indicator we call “odour footprint”, which considers the odour detection threshold, the diffusion rate and the kinetics of degradation of odourants, was implemented in MATLAB. We demonstrated the use of the characterisation factors we calculated in a case study based on odour removal technology applied to a pig barn.

Results and discussion

We produced a list of 33 linear characterisation factors based on hydrogen sulphide equivalents, analogous to the linear carbon dioxide equivalency factors in use in carbon footprinting, or the dichlorobenzene equivalency factors developed for assessment of toxic impacts in LCA. Like the latter, this odour footprint method does not take local populations and exposure pathway analysis into account—its intent is not to assess regulatory compliance or detailed design. The case study showed that despite the need for materials and energy, large factor reductions in odour footprint and eutrophication potential were achieved at the cost of a smaller factor increase in greenhouse emissions.

Conclusions

The odour footprint method is proposed as an improvement on the established midpoint method for odour assessment in LCA. Unlike it, the method presented here considers the persistence of odourants. Over time, we hope to increase the number of characterised odourants, enabling analysts to perform simple site-generic LCA on systems with odourant emissions.     

生境等价分析在溢油生态损害评估中的应用

生境等价分析是美国国家大气与海洋局在自然资源损害评估中的常用方法之一,但在我国鲜有应用.本文基于生境等价分析的理论研究,结合我国在溢油事故中的评估实践,将该方法改进后,应用于溢油生态损害评估中生境价值的计算.以我国某海域溢油事故的相关数据资料为依据,运用该方法计算修复受损生境的工程规模,并引入生态服务当量因子对各生境进行转化,最终实现了溢油生态损害评估中生境的价值化.     

Monitoring of Polymorphism – From Detection to Quantification

The polymorphic behavior of organic substances is driven by thermodynamic and kinetic factors. Therefore several solid phases may coexist. Since the properties of the solid state may be extremely relevant for the quality of medicines, the International Conference of Harmonization (ICH) requires a polymorphic study for new active ingredients. The different steps of investigations and the analytical methods which are used during the development phase in order to achieve adequately this challenging task, from detection to quantification are emphasized.