• Yoram Cohen, CERR Director, Chemical Engineering
• Michael Collins, School of Public Health
• Vijay Dhir, Mechanical and Aerospace Engineering
• L. Donald Duke, School of Public Health
• Menachem Elimelech, Civil & Environmental
• John Froines, School of Public Health
• Robert Gottlieb, Department of Urban Planning
• Tom Harmon, Civil & Environmental
• Shane Que Hee, School of Public Health
• Robert F. Hicks, Chemical Engineering
• William Kastenberg, Nuclear Engineering, UC Berkeley
• John D. Mackenzie, Material Science and Engineering
• David Okrent, Mechanical and Aerospace Engineering
• Julie Roque, Department of Urban Planning
• King-Ning Tu, Material Science and Engineering
• William Yeh, Civil & Environmental Engineering

• Janet Arey, UC Riverside
• Roger Atkinson, UC Riverside
• Ildafonso Cuesta, University of Tarragona
• David Eastmond, UC Riverside
• Francesc Giralt, University of Tarragona
• Jordi Grifoll, University of Tarragona
• Andrew Grosovsky, UC Riverside
• Eric Rahlfing, Sandia National Laboratory
• Gary S. Selwyn, Los Alamos National Laboratory
• Elain Vaughan, UC Irvine

• Eric Bescher, SEAS
• Rob Castro, SEAS
• Ron Faibish, SEAS
• Artemiy Fotinich, SEAS
• Katharine Gabor, PH
• Edward Hong, SEAS
• Chi-Yu Huang, PH
• James Y-J Jeong, SEAS
• Jeng-Dung Jou SEAS
• Harqkyun Kim, SEAS
• Yann Le Gouellec, SEAS
• Cindy Lin, PH
• Antonio Machado, PH
• Alexander Markov, SEAS
• Priti Mehta, SEAS
• Francis Pan, SEAS
• S.S. Park, SEAS
• Susan Pelmulder, SEAS
• Rania Sabty, PH
• Peter Sinsheimer, PPSR
• Zhongbin, Shu, SEAS
• Yung-Hsin Sun, SEAS
• Robert Van de Water, SEAS
• Yuhua Xie, SEAS
• Denise Yaffe, SEAS
• Huaying Yang, SEAS

• Dr. Pao C. Chau, Applied Mechanics and Engineering Sciences Department, University of California, San Diego
• Dr. Dale Hattis, Center for Technology, Environment, and Development, Clark University
• Dr. Hugo Loaiciga, Dept. of Geography & Environmental Studies, University of California, Santa Barbara
• Dr. T. McKone, School of Public Health, University of California, Berkeley
• Dr. Christian Seigneur, Vice President, Atmospheric and Environmental Research, Inc. (AER)
• Dr. Perry McCarty, Civil Engineering Department, Stanford University
• Dr. Tissa Illangasekare, Department of Civil Engineering and Applied Sciences, University of Colorado

Long-Term Risk at RCRA Sites

Professor Okrent and a team consisting of Zhongbin Shu, a PhD candidate, and two undergraduate researchers, Mariam Delacruz of Chemical Engineering, and Raul Krishnaswamy of Microbiology, are examining issues related to how long term risk is being handled in the cleanup of superfund sites, in RCRA hazardous waste repositories and for tailing and other residues of mining. They are currently accumulating a short list of sites where the contents include large quantities of elements such as arsenic, nickel, cadmium, mercury, and /or chromium carcinogens or other persistent contaminants. Of interest already is that some sites pose long term risks from the disintegration of embankments which hold back large quantities of material containing large concentrations of such hazardous metals.

CERR Graduate Research Fellowships

On January 19, 1996, the Center for Environmental Risk Reduction presented the following students with research fellowships:

Harqkyun Kim, Department of Materials Science & Engineering
Priti Mehta, Department of Civil & Environmental Engineering
Chi-Yu Huang, Department of Environmental Health Sciences
Antonio Machado, Department of Environmental Health Sciences

Yann Le Gouellec de Schwarz, Department of Civil & Environmental Engineering
James Yoon-Jae Jeong, Department of Chemical Engineering.

The purpose of these fellowships is to encourage and support graduate students who are interested in environmental science, engineering, and policy issues that pertain to the overall theme of environmental risk reduction. The CERR congratulates and welcomes our new graduate student members who were awarded the competitive research fellowships.

Professors Roger Atkinson, Janet Aery, Andrew Grosovsky, Dave Eastmond and their students, Jennifer Sasaki, Punna Pongsaensook, and Krista Dobo from UC Riverside and UCLA Professor Yoram Cohen and his student, Denise Yaffe are evaluating the importance of accounting for nitro-PAHs in assessing the multimedia impact of PAHs. The UCR/UCLA team is focusing on a selected number of PAHs and their nitro-PAHS transformation products. The issue at hand is to determine the level of increased health risk due to the daughter-products (nitro-PAHs) of PAHs. It is important to note that the current regulatory approach to assessing the health risks associated with toxic air pollutants does not consider daughter products. Thus, the UCR/UCLA study should provide needed guidance on the assessment of the environmental impact of toxic air pollutants.

Pollution Prevention: Collaborations and Partnerships

The Center for Pollution Prevention Education and Research Center (PPERC) has joined the Center for Environmental Risk Reduction to become one of the CERR major thrust areas. This combined effort will allow CERR faculty and students to address pollution prevention issues with the added perspective of a complete life-cycle analysis which considers both risk analysis and risk reduction in addition to the common considerations of energy and cost. It is also important to note that despite the prevalence of cost effective and technically sound pollution prevention solutions, social and institutional decision-making factors can create barriers to their implementation. A successful pollution prevention program requires a partnership strategy which includes consumer and labor, as well as industry. This partnership is needed to better understand the range of social, institutional, and industrial decision-making factors that influence pollution prevention outcomes in order to fully explore the opportunities for; as well as the barriers to, pollution prevention. This concept is illustrated in the recent projects: Wet Cleaning Demonstration Project and Safe Cleaning Products for Janitorial Service Work which are described in the pollution prevention and risk reduction section of this newsletter.

Mortality Study to Determine Excess Risk to Chemicals and Radiation at Rockwell/Rocketdyne Facilities

This three-year project is a cohort mortality study designed to determine if there is excess cancer mortality associated with employment and radiation/chemical exposure at Rockwell/Rocketdyne facilities in southern California. The study arises as a result of community concerns that there may be increased risk of cancer among the general population that surrounds the test facilities as well as excess risk among workers over a period of approximately 30 years. A retrospective mortality study using death certificates and retrospective exposure assessment is being conducted by UCLA researchers to determine whether there is increased mortality and whether it can be attributed to specific chemical or radiation exposures. (Hal Morgenstern and John Froines, Advisors; Beate Ritz, Nola Kennedy, and Nani Kadrichu, Researchers)

Replacing Lead with Bismuth in Brass Faucets

Contamination of drinking water can occur as a result of lead leaching from brass faucets and other fixtures. The presence of lead in drinking water creates serious health consequences for children. To address this problem, we are working with a faucet manufacturer to investigate the feasibility of replacing lead with the metal bismuth in brass faucets. A first step in this process has been to determine whether bismuth is a suitable nontoxic alternative, and whether it meets the technological needs of faucet manufacturers. In addition to toxicological and chemical engineering issues, there are policy questions concerning how to meet the regulatory requirements for lead in drinking water once bismuth has been substituted (a small amount of residual lead will be present in the product). This issue concerns the ongoing monitoring of lead in drinking water and what constitutes compliance with the existing California standard. This project will address all three issues: the toxicology of bismuth to ensure that an equally toxic material is not used to replace lead; how to manufacture brass containing bismuth, and whether the resulting product meets the needs of consumers; and how to meet the regulatory requirements of the state of California. (John R. Froines, Advisor; Deborah Campbell, Researcher)

Wet Cleaning Demonstration Project This demonstration project developed out of an earlier study of the problems associated with perchloroethylene (PERC) use in dry cleaning. Dry cleaners are a major consumer of PERC, a toxic chemical listed by federal and state regulators as a hazardous air pollutant, and as a probable human carcinogen. Because of the prevalence of dry cleaning shops, perc poses a health and environmental risk in nearly every community in the U.S. Until recently, no effective alternative to chemical dry cleaning was available. Now, new technologies such as "wet cleaning" have the potential to significantly reduce or even eliminate the use of dry cleaning chemicals. However, much work is needed to further commercialize this new technology and make wet cleaning a viable and widely available alternative. CERR researchers will conduct a multi-dimensional evaluation of the demonstration shop over a period of one year. The tests will: (1) measure the effectiveness of wet cleaning compared to dry cleaning under market conditions, adding to and complementing the efforts of other wet cleaning studies; (2) measure consumer acceptance of and attitudes toward wet cleaning; (3) measure and compare financial performance of a wet cleaning shop to a typical dry cleaning shop; (4) measure and compare the energy and water use of a wet cleaning shop to a typical dry cleaning shop; and (5) study the job creation potential of wet cleaning. The findings of this research will be used to educate the local dry cleaning industry about wet cleaning alternatives and encourage the use of non-toxic alternatives. (Robert Gottlieb, Advisor; Elizabeth Hill and Peter Sinsheimer, Research Associates)

Safe, Cleaning Products for Janitorial Service Work

Cleaning products used for janitorial service work in commercial establishments such as offices, hotels, restaurants and other buildings represent a potentially significant source of occupational and environmental hazards. However, strategies to identify and prevent such hazards are nearly non-existent. Common risk evaluation procedures have been difficult to design because of the small number of workers exposed to those substances in any particular workplace. However, an analysis of risk across the entire population of service workers or across sites of exposure may reveal a significant source of risk and threat to human health. Exposure issues are compounded by poor training in handling hazardous materials, the lack of basic safety procedures and the limited nature of available information about product hazards and their potential for exposure. This project is designed to explore potential pollution prevention and risk evaluation decision-making models to address the hazards of commercial cleaners impacting both the workplace and the environment. The project will undertake five related tasks: (1) a preliminary quantitative risk assessment of cleaning product hazards; (2) an evaluation of the risk adaptation and risk perception of janitorial service workers, and opportunities for identifying pollution prevention options to reduce risk; (3) an examination of the structure of the janitorial services industry in relation to the barriers and possible entry points for pollution prevention activity; (4) an analysis of the possibilities for pollution prevention-based product substitution, workplace activities and the methods required for evaluating such alternative products and procedures; and (5) the design of a pollution prevention and risk evaluation decision making model. The project will build on existing case studies of commercial cleaners used in janitorial service work, quantitative evaluations of extant risk data on relevant workplace chemicals, and parallel research evaluating risk perception and adaptation in varied sociocultural contexts. Specific case studies will be conducted in collaboration with the City of Santa Monica and major retailers and commercial property owners. (Robert Gottlieb, Elaine Vaughan (UC Irvine), John Froines, Advisors; Andrea Gardner and Nancy Ngugi, Researchers)

Ceramic-Supported Polymeric Membranes

Ceramic membranes are being used in a wide range of separation applications due to their superior physical stability and chemical resistance to industrial solvents. However, the advantages ceramic membranes offer are offset by their low selectivity. Improvements in selectivity are therefore necessary in order to make ceramic membrane-based systems a viable option for applications such as water purification and pollution abatement. In order to improve the selectivity of ceramic membranes, CERR researchers have developed a graft polymerization technique to chemically bond polymer chains onto the surface of microporous ceramic membranes. The goal in grafting a polymer brush layer on the surface of a microporous ceramic membrane is to develop a new hybrid membrane which couples the selectivity of the polymeric surface phasae with the mechanical properties of a ceramic membrane. The selectivity of the resultant ceramic-supported polymeric (CSP) membrane is determined by the configuration of the polymer brush layer and the functionality of the grafted polymer. If the solvent-polymer interactions are weaker than the polymer-polymer interactions, the chains are collapsed against the surface. When the solvent-polymer interactions are stronger than the polymer-polymer interactions, the chains extend away from the surface. In this situation, the selectivity of the membrane is influenced by the solute-polymer interactions. The extent to which the selectivity of the microporous ceramic membrane is altered depends on a number of parameters, such as surface coverage, density and length of the grafted chains and the functionality of the polymeric material. Since the polymer phase is chemically bonded to the ceramic support membrane, the polymer layer can be engineered for optimum selectivity without the structural constraints associated with polymeric membranes. The first generation CSP membranes were developed with the water soluble polymer poly(vinylpyrrolidone) (PVP) with silica disk and tubular a-alumina ceramic supports. Exposure to an aqueous or polar solvent is expected to lead to swelling of the PVP chains away from the pore surface. For solutions consisting of a polar solvent and a non-polar solute, the hydrophilic PVP chains should preferentially allow the passage of solvent and repulsion of the hydrophobic solute. The presence of the grafted polymer should also inhibit adsorption of the solute (i.e. membrane fouling) due to the increased hydrophilicity of the surface. This premise has been investigated with the application of the CSP membranes to the cross-flow filtration of stable oil-in- water emulsions. A sample of the preliminary are presented in Figure 1. In this figure, both the permeability and permeate concentration of a 4100A pore size silica support and silica-PVP CSP membrane are presented. As illustrated, the CSP membrane provides a 25% reduction in the total organic carbon (TOC) level of the permeate stream (feed stream = 41,000 ppmTOC) while maintaining approximately the same permeability of an unmodified support. The current focus is on the development of tubular a-alumina/PVP CSP membranes, since this support geometry is more robust and provides for a more convenient and practical flow configuration. (Yoram Cohen and Harold Monboquette, Advisors; Robert Castro and Jeng-Dung Jou, Research Assistants)

Removal of Organic Contaminants from Water Using Sorbent Resin Beds by Cyclic Adsorption and Regeneration
Compact adsorption units can replace gigantic distillation and extraction towers in the chemical process industries. This according to a recent cover story, "For Your Next Separation Consider Adsorption" in the November 1995 issue of Chemical Engineering.

Today, adsorption separation methods commonly employ a continuous separation of a feed mixture utilizing two or more packed beds where cycles of adsorption and onsite regeneration take place alternatively and sequentially. With new developments in selective sorption resins adsorption processes are ideal for in-plant chemical recovery and recycle. In order to test proposed new resins and adsorption/regeneration processes there is a need for experimental performance data and appropriate models to allow the scale-up of such processes. At the CERR, Dr. Illam Park and M.S. student, Alexander Markov, are evaluating new polymeric resins, having surface areas exceeding that of activated carbon, for use in cyclic adsorption and regeneration processes. The polymeric resins being studied are the high surface are polystyrene-based MN-150 and MN-170 macronet resins recently developed by Purolite, Inc. For water purification. The macronet resins, which have a higher sorption capacity than the presently available commercial polymeric resins, can be easily regenerated in-situ using aliphatic alcohols. In the adsorption step, contaminated water is pumped into one end (feed end) of a resin bed (which has been regenerated in previous cycle). The contaminant in water is captured by adsorption in the bed while purified water is produced at the outlet (product end) and stored in a purified water reservoir. This step is typically terminated before the bed is fully loaded (saturated) with the contaminant, to keep the purity of water at a certain level. Most of the loaded contaminant is purged from the bed in the desorption step during which the stream of alcohol (e.g. methanol) elutes the contaminant from the resin and carries it out of the bed. The spent alcohol may be restored and reused unless the level of contaminant in methanol reaches a critical limit. In the final step, a portion of purified water is use d to displace the alcohol filling the desorbed bed from the previous step. In this way, the bed is completely regenerated and filled with pure water before the oncoming feed step of the next cycle.

Typical breakthrough and regeneration for the removal of benzoic acid are shown in Figure 1. In this illustration benzoic acid is concentrated in methanol by a factor of about sixty. In order to theoretically predict the dynamic behavior of the adsorption/regeneration system, a multiphase mass transfer model capable of accounting for nonlinear adsorption isotherms was developed. The computer simulation based on this model is now being performed interactively on the IBM/SP2 Cluster at UCLA using the numerical software IMSL/MOLCH and the Xgrafix visual aid (from the University of California, Berkeley). As shown in Figure 1, the predictions agree with the experimentally obtained dynamic behavior of the system. Current experimental efforts are focused on obtaining dynamic adsorption/regeneration data over a wide range of conditions in order to test the validity of the simulation in various conditions. Once the model is tuned, simulations of the cyclic process will be carried out for the separation cycle shown in Figure 2. It consists of three steps; (i) adsorption (or feed) step, (ii) desorption (or purge) step, and (iii) rinse step. What size of bed will be required for this purification process? How should we schedule each cyclic step for required water purity or production for a single bed or multiple beds? What is the operating cost versus water purity? These questions can be answered most conveniently by combining a basic experimental data set with a computer model to accurately simulate the adsorption/regeneration unit behavior over many cycles. The approach of using polymeric resins in pollution prevention applications is a developing area and this CERR project will help provide better design tools and data to optimize the design of polymer resin adsorption separation processes. (Dr. Illam Park and Alexander Markov)

Castro, R., H. Monbouquette, and Y. Cohen, "Polyvinvlpyrrolidone-Silica Membranes for the Treatment of Oil-in-Water Emulsions," J. Membrane Science, in press 1996.

Cohen, Y., "Volatile Organic Compounds in the Environment: A Multimedia Perspective," in Volatile Organic Compounds in the Environment, ASTM Special Technical Publication, Wang, W., J. Schnoor, and J. Doi (Eds.), in press 1996.

Cohen, Y. and F. Giralt, "Strategies for Pollution Prevention: Waste Minimization of Source Reduction," Afinidad:Revisita de Química Teórica y Aplicada, in press 1996.

Cohen, Y. and J. Klein, "Removal of Organics from Aqueous Systems," in Novel Adsorbents and their Environmental Applications, AIChE Symp. Series, 91, 72-78, 1995.

Froines, J.R., W.V. Liu, D.H. Wegman, and W.C. Hinds, "Prediction of Blood Lead Levels in Occupationally Exposed Workers Using Toxicokinetic Modeling and Empirically-Derived Size Distribution Data: Regulatory Implications," Occupational Hygiene, 1, 279-292, 1995.

Grifoll, J. and Y. Cohen, "Chemical Movement in the Unsaturated Soil Zone During Rainfall," J. Contaminant Hydrology, in press 1996.

Hsu, K.H., J.R. Froines, and C.J. Chen, "Studies of Arsenic Ingestion from Drinking Water in Northeastern Taiwan: Chemical Spciation and Urinary Metabolites," Proc. of the Third. Annual Conference on Arsenic, W. Chappell, Ed., In Press, 1996. Johnson, P.R., and M. Elimelech, "Dynamics of Colloid Deposition in Porous Media: Blocking Based on Random Sequential Adsorption", Langmuir, Vol. 11, 801-812, 1995.

Kim, H.K. and K.N. Tu, "Rate of Consumption of Cu in a Soldering Reaction Accompanied by Ripening Reaction," Appl. Phys. Lett., 67, 2002-2004, 1995.

Kim, H.K., H.K. Liou, and K.N. Tu, "Morphology of Instabiliity of Wetting Tips of Eutectic SnBi, Eutectic SnPb, and Pure Sn on Cu," J. of Materials Research, 10, 497-504 , 1995.

Kim, H.K., H.K. Liou, and K.N. Tu, "Three-Dimensional Morphology of the Interface between SnPb Solder and Cu Substrate," Appl. Phys. Lett., 66, 2337-2339, 1995.

Kim, H.K., Y. Wang, A. Maheshwari, and K.N. Tu, "Wetting Behavior of Sn-Based Solders on Cu and Pd Surfaces," Proc. of MRS Symp. On Electronic Packaging Materials Science VIII, Vol. 390, 183-188, 1995.

Liu, D., P.R. Johnson, and M. Elimelech, "Colloid Deposition Dynamics in Flow Through Porous Media: Role of Electrolyte Concentration", Environmental Science & Technology, Vol. 29, 3021-3031, 1995.

Okrent, D. and L. Xing, "Future Risk from a Hypothesized RCRA Site Disposing of Carcinogenic Metals, Should a Loss of Societal Memory Occur", J. Hazardous Materials, 38, 363-384, 1993.

Okrent, D., "On Intergenerational Equity and Policies to Guide the Regulation of Wastes Posing Very Long Term Risks", UCLA School of Engineering and Applied Science Report, UCLA-ENG, 22-94, January 1994.

Pelmulder, S., W.W.G. Yeh, and W.E. Kastenberg, "Regional Scale Effects of Aquifer Parameters on Exposure," Proc. of the 22nd Annual Conf. of the Water Resources Planning and Management Division, ASCE, Cambridge, Massachusetts, May 7-11, 836-839, 1995.

Pelmulder, S.D., W.W-G. Yeh, and W.E. Kastenberg, "Regional Scale Framework for Modeling Water Resources and Health Risk Problems," Water Resources Research, In press, 1995.

Ryan, J.N., and M. Elimelech, "Colloid Mobilization and Transport in Groundwater", Colloids and Surfaces A, Vol. 107, 1-56, 1996.

Song, L. and M. Elimelech, "Particle Deposition onto a Permeable Surface in Laminar Flow" Journal of Colloid and Interface Science, Vol. 173, 165-180, 1995.

Song, L. and M. Elimelech, "Theory of Concentration Polarization in Crossflow Filtration", Journal of The Chemical Society, Faraday Transactions , Vol. 91, 3389-3398, 1995.

Stein, E., A. Winer, and Y. Cohen, "Mercury in the Environment," Critical Reviews in Environmental Science, 26, 1-43, 1996.

Sun, Y.H. and W.W-G. Yeh, "Mixed Integer Nonlinear Optimization of Soil Vapor Extraction Systems," Proc. of the 22nd Annual Conf. of the Water Resources Planning and Management Division, ASCE, Cambridge, Massachusetts, May 7-11, 883-886, 1995.

Sun, Y.H., M.W. Daver, and W.W-G. Yeh,, "Soil Vapor Extraction System Design by Combinatorial Optimization," Water Resources Research, in press 1996.

Wang, Y. and K.N. Tu, "Ultrafast Intermetallic Compound Formation in a Bulk Diffusion Couple of Eutectic SnPb and Pd where the Intermetallic is not a Diffusion Barrier," Appl. Phys. Lett., 67, 1069-1071, 1995.

Wang, Y. , H.K. Kim, H.K. Liou, and K.N. Tu, "Rapid Soldering Reactions of Eutectic SnBi and Eutectic SnPb Solders on Pd Surfaces," Scripta Metallurgica and Materials, 32, 2087-2092, 1995.

Wilson, P.M., D.K. La, and J.R. Froines, "Hemoglobin and DNA adduct formation in Fischer rats exposed to 2,4 and 2,6-toluene diamine," Archives of Toxicology, in press 1996.

Zhu, X., and M. Elimelech, "Fouling of Reverse Osmosis Membranes by Aluminum Oxide Colloids, "Journal of Environmental Engineering, ASCE., Volume 121, 884-892, 1995.

Zio, E., G.E. Apostolakis, and D. Okrent, "Toward a Quantitative Treatment of Model Uncertainty in the Performance Assessment of High-Level Radioactive Waste Repositories," Proc., Int. Conf. Radioactive Waste'95, Tucson, February 1995.

Zio, E., G.E. Apostolakis, and D. Okrent, "On the Use of Expert Opinion in the Assessment of Model Uncertainty," Proc. Int. Conf. on Radioactive Waste Management and Environmental Remediation, Berlin, September 1995.

Books and Environmental Volumes

Cohen, T., R. Sabty, and J.R. Froines, "Substituting for Lead: The Radiator Repair Industry, Reducing Toxics: A New Approach to Policy and Industrial Decisionmaking, R. Gottlieb, Ed., Chp. 10, 332-358, 1995.

Cohen, Y. and R.W. Peters, Novel Adsorbents and their Environmental Applications, AIChE Symposium Series, Volume 91, 1995, American Institute of Chemical Engineering, New York.

Elimelech, M., J. Gregory, X. Jia, and R. A. Williams , "Particle Deposition and Aggregation: Measurement, Modeling, and Simulation", Butterworth-Heinemann, Oxford, 1995.

Froines, J.R., R. Gottlieb, M. Smith, and P. Yates, "Disassociating Toxics Policies: Occupational Risk and Product Hazards," Reducing Toxics: A New Approach to Policy and Industrial Decisionmaking, R. Gottlieb, Ed., Chp. 4, 95-123, 1995.

"Reducing Toxics: A New Approach to Policy and Industrial Decision-Making." Robert Gottlieb, Ed., Island Press, 1995.