A Risk-Based Approach to Health Impact Assessment for Input-Output Analysis, Part 1: Methodology (7 pp)

Goal, Scope and Background Incorporation of exposure and risk concepts into life cycle impact assessment (LCIA) is often impaired by the number of sources and the complexity of site-specific impact assessment, especially when input-output (I-O) analysis is used to evaluate upstream processes. This makes it difficult to interpret LCIA outputs, especially in policy contexts. In this study, we develop an LCIA tool which takes into account the geographical variability in both emissions and exposure and which can be applied to all economic sectors in I-O analysis, relying on screening-level risk calculations and methods to estimate population exposure per unit emissions from specific geographic locations. Methods We develop our analytical approach with reference to the case of increasing insulation for new single-family homes in the US. We quantify the public health costs from increasing insulation manufacturing and compare them with the benefits from energy savings, focusing on mortality and morbidity associated with exposure to primary and secondary fine particles (PM2.5) as well as cancer risk associated with exposure to toxic air pollutants. We use OpenLC to estimate the incremental economic outputs induced by increased insulation and reduced fuel consumption and calculate emissions from a sector-specific pollution intensity matrix. We calculate sector-specific intake fractions (dimensionless ratios between the amount of pollutant intake and the amount of a pollutant emitted) using previously-derived regression models and apply these values to the supply chain emissions of fiberglass and fuel sources. We refine the exposure estimates for selected emission sites and pollutants that contribute significantly to total health impacts, running site-specific air dispersion models. We estimate health impacts using concentration-response functions from the published literature and compare the costs and benefits of the program by assigning monetary values to the health risks. In the second part of this paper, we present the results of our case study and consider the implications for incorporating exposure and risk concepts into I-O LCA.     

A Risk-Based Approach to Health Impact Assessment for Input-Output Analysis, Part 2: Case Study of Insulation (8 pp)

Goal, Scope and Background In the first part of this paper, we developed a methodology to incorporate exposure and risk concepts into life cycle impact assessment (LCIA). We argued that both risk assessment and LCIA are needed to consider the impacts of increasing insulation for single-family homes in the US from current practice to the levels recommended by the 2000 International Energy Conservation Codes. In this analysis, we apply our model to the insulation case study and evaluate the benefits and costs of increased insulation for new housing. Results and Discussion The central estimate of impacts from the complete insulation manufacturing supply chain is approximately 14 premature deaths, 400 asthma attacks, and 7000 restricted activity days nationwide for one year of increased fiberglass output. Of the health impacts associated with increased insulation manufacturing, 83% is attributable to the supply chain emissions from the mineral wool industry, which is mostly associated with the direct primary PM2.5 emissions from the industry (98%). Reduced energy consumption leads to 1.2 premature deaths, 33 asthma attacks, and 600 restricted activity days avoided per year, indicating a public health “payback period” on the order of 11 years. Over 90% of these benefits were associated with direct emissions from power plants and residential combustion sources. In total, the net present value of economic benefits over a 50-year period for a single-year cohort of new homes is $190 million with a 5% discount rate, with 49 fewer premature deaths in this period. Conclusion Recommendation and Outlook. We have developed and applied a risk-based model to quantify the public health costs and benefits of increased insulation in new single-family homes in the US, demonstrating positive net economic and public health benefits within the lifetimes of the homes. More broadly, we demonstrated that it is feasible to incorporate exposure and risk concepts into I-O LCA, relying on regression-based intake fractions followed by more refined dispersion modeling. The refinement step is recommended especially if primary PM2.5 is an important source of exposure and if stack heights are relatively low. Where secondary PM2.5 is more important, use of regression-based intake fractions would be sufficient for a reasonable risk approximation. Uncertainties in our risk-based model should be carefully considered; nevertheless, our study can help decision-makers evaluate the costs and benefits of demand-side management policy options from a combined public health and life cycle perspective.     

A New LCA Methodology of Technology Evolution (TE-LCA) and its Application to the Production of Ammonia (1950-2000) (8 pp)

Goal, Scope and Background

This paper presents a new LCA method of technology evolution (TE-LCA), and its application to the production of ammonia, the second largest chemical product in the world, over the last fifty years. The TE-LCA of a chemical process is the procedure in which historical information on a process, mainly the evolution of technical parameters, is translated by simulation to mass and energy balances as a function of time. These mass and energy balances are then transformed into environmental impact indicators using common LCA approaches. Finally, the evolution of environmental impact resulting from the investigated process can be related to its technical and other, i.e. legislative, developments.

Methods

The technological evolution of the production of ammonia was compiled according to three basic sources of information: patents, publications and industry data. From these sources in a first step, the major technological advances of the process were identified as a function of time delivering different process variants that were modelled using the simulation software Aspen Plus®. In a second step, the evolution of environmental regulations is studied. For those energy related emissions that were regulated, e.g. SOx and NOx, it was assumed that threshold values defined in legislation were realized immediately. The aggregation of both steps allows the calculation of the emissions resulting from the production (cradle to gate view) of the investigated chemical as a function of time.

Results and Discussion

The application of the TE-LCA to the production of ammonia revealed when and to which extent technological and legislative developments resulted in the reduction of energy related emissions in the production of this chemical compound. Overall, the reduction of emissions from ammonia production was highly influenced by the technological development and only to a lower extent by environmental regulations.

Conclusion

The results obtained from the TE-LCA method is useful to reveal how the environmental performance of a process developed in the past and to identify the reasons for this development. The investigated case study of ammonia production shows that investment in technological development also paid off in terms of being ahead of tightened environmental legislation that might bear potential cost consequences such as carbon dioxide tax.

Outlook

The presented method can be easily extended by including an economic analysis, which provides additional information on why certain technological developments were enforced and which the economic consequences of changes in environmental legislation were. The new methodology has to be applied to additional case studies, i.e. to other chemical sectors than basic chemicals and to other branches than chemicals. In other chemical sectors, toxic emissions from the production process might have to be considered and trade-offs between these and the overall energy consumption might result.     

Bioaccumulation of Key Metals and Other Contaminants by Seaweeds from the Egyptian Mediterranean Sea Coast in Relation to Human Health Risk

This study examined the bioaccumulation of key metals and other contaminants (SO₄, F, Na, K, Ca, Mg, P, Si, Fe, Mn, Zn, Ni, Co, Cu, and Cd) by seaweeds from the Egyptian Mediterranean Sea coast and their risk to human health. Bioaccumulation factor calculations indicated that S, F, Na, K, Zn, Cu, and Cd had high seaweed uptake and this referred to the potential pollution of the coastal area. Multivariate analysis of the studied contaminants confirmed the bioaccumulation factor results as well as the physiological processes in seaweeds. Human health risk assessment of F, Mn, Zn, Ni, Cu, and Cd was conducted using hazard quotient (HQ) and incremental lifetime cancer risk (ILCR) analyses. The carcinogenic assessment of sediments and ingestion of seaweeds using ILCR calculations revealed that Mn, Ni, and Cd in sediments and F and Zn in seaweeds require remedial action in order to reduce their human health risks. Additionally, HQ calculations for the contaminants in seaweeds and reference to toxicological references values from different agencies revealed that F and Co present high human health risk effects. Consequently, the potential public health risks from dietary exposure to hazardous contaminants in seaweeds must be continually subjected to research, regulation, and debate.     

Risk Analysis,Uncertainty Factors,and the Susceptibilities of Children

This article examines the use of uncertainty factors (UFs) by the Agency for Toxic Substances and Disease Registry (ATSDR) when developing health guidance values known as minimal risk levels (MRLs) in environmental risk analysis as it applies to children. Improvements in the chemical-specific databases often reveal new information and thereby reduce uncertainty or alternatively raise new concerns. As a result, MRLs can and will change. Children, in particular, are not “small adults” and in some instances demonstrate greater risks of exposure to environmental toxicants and greater susceptibility for adverse health effects once exposed. Recent experience with risk analysis for three toxicants (organic mercury, dioxin, and manganese) is recounted to demonstrate how ATSDR has revised MRLs as the emerging science generates greater knowledge and awareness of children's special vulnerabilities to toxic substances in the environment.     

Synthesis and FTIR Conformational Studies of Peptides From the Basic Region of c-Jun: a Critical Analysis on the Basis of CD and NMR Data

Abstract

The peptide (35 residues) corresponding to the basic subdomain (bSD) of c-Jun (residues 252–281) and its fragments NP (N-terminal peptide, 1–19) and CP (C-terminal peptide, 1635) were synthesized in stepwise solid-phase using the tert-butyloxycarbonyl/benzyl strategy. In a previous paper, we have shown that during its binding to the DNA site CRE (cAMP- responsive element) the bSD structure was converted into α-helix from an initial random coil conformation [Krebs, D., Dahmani, B., El Antri, S., Monnot, M., Convert, O., Mauffret, O., Troalen, F. & Fermandjian, S. Eur. J. Biochem. 231, 370–380 (1995)]. Our results suggested both a high flexibility and a helical potential in bSD, these two properties seeming crucial for the accommodation of the basic subdomain of c-Jun to its specific DNA targets. In this work, we assessed the conformational variability of bSD through the study of the secondary structures of its NP and CP fragments in trifluoroethanol (TFE)/²H₂O mixtures, using Fourier transform infrared (FTIR) spectroscopy. The IR results were critically analyzed in light of our previously reported circular dichroism (CD) and NMR data [Krebs, D., Dahmani, B., Monnot, M., Mauffret, O., Troalen, F. & Fermandjian, S. Eur. J. Biochem. 235, 699–712 (1996)]. Upon addition of TFE, the relative areas of the seven components of the amide I band (1700–1620 cm^?1) reflected the conversion of a large amount of random coil conformation into α-helix for the two fragments and bSD. This effect was accompanied by more subtle variations of the less populated structures, in agreement with the results of CD and NMR experiments. The IR results stipulated the conservation of the parent bSD secondary structures in both fragments; however, NP and CP peptides did not display similar random-to-α-helix stabilization pattern upon additions of TFE to aqueous solutions. The profile from CD signal at 222 nm was found sigmoidal for NP and almost linear for CP, while that corresponding to the parent peptide bSD was just in between those of its fragments. Thus, the present study confirms the high flexibility and helix propensity of the c-Jun basic subdomain and suggests that the N- and C-terminal parts of the peptide do not follow the same random-to-helix conversion profile during their complexation with DNA.     

Human Health Risk Assessment of Soils Contaminated with Metal(loid)s by Using DGT Uptake: A Case Study of a Former Korean Metal Refinery Site

The human health risk of soils contaminated with As, Pb, Cu, and Zn was evaluated based on pseudo-total concentrations of metal(loid)s, the physiologically based extraction test (PBET), and diffusive gradients in thin films (DGT). Non-carcinogenic (NCR) and carcinogenic (CR) risks exceeded the U.S. Environmental Protection Agency criteria under both the residential and non-residential scenarios. Human bioavailable concentrations (PBET) were much lower than pseudo-total concentrations. The Hazardous Index of NCR (HI (NCR)) for the PBET in the studied soils was 67% and 94% less than that for pseudo-total concentration, respectively, under the non-residential and residential scenarios. Similarly, CR for the PBET was also 65% and 93% less for the two soils. The concentration of metal(loid)s accumulated in the DGT resin was highly correlated with the PBET-extractable concentration (R² > 0.649). Therefore, for both the CR and HI (NCR), the DGT-calculated risk was linearly related to the PBET-calculated risk for the studied soils under both scenarios. The results suggest that DGT uptake and PBET-extracted concentrations are good surrogates for risk estimation and that both J1 and J2 soils require remediation before their use for residential or non-residential purposes.     

Generation of a 'humanized' hCYP1A1_1A2_Cyp1a1/1a2(-/-)_Ahrd mouse line harboring the poor-affinity aryl hydrocarbon receptor

Herein, we describe generation of the hCYP1A1_1A2_Cyp1a1/1a2(−/−)_Ahr^d mouse line, which carries human functional CYP1A1 and CYP1A2 genes in the absence of mouse Cyp1a1 and Cyp1a2 genes, in a (>99.8%) background of the C57BL/6J genome and harboring the poor-affinity aryl hydrocarbon receptor (AHR) from the DBA/2J mouse. We have characterized this line by comparing it to our previously created hCYP1A1_1A2_Cyp1a1/1a2(−/−)_Ahr^b1 line—which carries the same but has the high-affinity AHR of the C57BL/6J mouse. By quantifying CYP1A1 and CYP1A2 mRNA in liver, lung and kidney of dioxin-treated mice, we show that dose-response curves in hCYP1A1_1A2_Cyp1a1/1a2(−/−)_Ahr^d mice are shifted to the right of those in hCYP1A1_1A2_Cyp1a1/1a2(−/−)_Ahr^b1 mice—similar to, but not as robust as, dose-response curves in DBA/2J versus C57BL/6J mice. This new mouse line is perhaps more relevant than the former to human risk assessment vis-à-vis human CYP1A1 and CYP1A2 substrates, because poor-affinity rather than high-affinity AHR occurs in the vast majority of the human population.     

Analysis of the membrane-associated poly(A)+RNA in the cytoplasm of dormant Artemia cysts by DNA excess hybridization: Evidence for a nuclear origin

Encysted embryos of Artemia contain latent mRNA, to a large extent associated with a fraction of cytoplasmic membranes. The membranes, purified by EDTA treatment and banding in a sucrose gradient at 1.17 g/cm³, include endoplasmic vesicles and mitochondria. The origin of the membrane-associated poly(A)⁺RNA was therefore investigated. In gel electrophoresis poly(A)⁺RNA from the purified membranes of dormant cysts forms two distinct bands at approx. 3·10⁵ and 5·10⁵ Da. Later during development the lighter component decreases. Nuclei from dormant cysts are devoid of poly(A)⁺RNA, while nuclei from developing embryos (50% emergence) contain a predominant poly(A)⁺RNA component of approx. 5·10⁵ Da. ¹²⁵I-labelled preparations of nuclear DNA and of nuclear and membrane-associated poly(A)⁺RNA were used in reassociation and hybridization experiments with excess nuclear DNA. Poly(A)⁺RNA from the membranes of dormant cysts hybridized to nuclear DNA to the same extent as the nuclear poly(A)⁺RNA from developing embryos. The hybridization of labelled, nuclear poly(A)⁺RNA to nuclear DNA was strongly inhibited by unlabelled membrane RNA from either dormant cysts or developing embryos. It is concluded that the stored, membrane-associated poly(A)⁺RNA in dormant cysts is essentially of nuclear origin. The 5·10⁵-Da component is largely homologous with the corresponding component of nuclear poly(A)⁺RNA at later stages.