EPA Standards Research Articles

The Beat

Vol. 117, No. 8 EnvironewsOpen AccessThe Beat Erin E. Dooley Erin E. Dooley Search for more papers by this author Published:1 August 2009https://doi.org/10.1289/ehp.117-a346bAboutSectionsPDF ToolsDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InReddit Hearing Loss Express?Richard Neitzel et al. report in the August 2009 American Journal of Public Health that New York City subways are loud enough to increase the risk for noise-induced hearing loss, an irreversible condition affecting about 250 million people worldwide. Subway platforms were the noisiest of the environments studied, with decibel levels higher than that of a chainsaw, but other forms of mass transit also were loud enough to present a risk of hearing loss with prolonged exposure. The researchers suggest that mass transit riders reduce noise exposure using earplugs or earmuffs—but not headphones or earbuds, since wearers often turn up the music to drown out ambient noise.Cell Phones Banned in French SchoolsThe French government has banned cell phones from primary school grounds and directed manufacturers to offer handsets that allow only text messages and phones that work only with headsets. The decision follows a six-week review of mobile phone use and wireless radiation, including reports of an association between childhood use of cell phones and increased risk of adult cancer published 4 April 2009 by Lennart Hardell et al. ahead of print in a special issue of Pathophysiology. But even these measures are deemed inadequate by advocates seeking a complete ban on mobile phone use by children under age 14 and limits on the power and siting of cell phone masts and towers.Workshops for African Medical Journal EditorsThe African Journal Partnership Project (AJPP), established in 2004 by the National Library of Medicine and the Fogarty International Center, promotes capacity-building efforts for medical journals in Africa. To advance its goals, the AJPP is now planning four train-the-trainer workshops—a September 2009 workshop in Ghana will combine training for editorial and computer support staff; later workshops in Ethiopia, Uganda, and Zambia will focus on scientific writing and reviewing skills. More information about the AJPP is available at http://www.ehponline.org/international/. AJPP member EHP has partnered with Mali Médical since the project’s inception.Cozy Cancer RiskThe EPA’s 2002 National-Scale Air Toxics Assessment, released in June 2009, shows that the polycyclic aromatic hydrocarbons released by wood-burning fireplaces and stoves contribute the most to the cancer risk from breathing Oregon’s air. Oregon ranked third in the nation after New York and California in the number of people living in census tracts with elevated population exposures, but this ranking may be due to Oregon’s unusually thorough documentation of wood stove and fireplace use, which is particularly popular for home heating in the western half of the state. To minimize toxic emissions, the American Lung Association recommends burning only clean, dry, seasoned hardwood and regular maintenance to prevent creosote buildup in flues.CO Damages Fetal Rat Brain CellsIn work published 27 May 2009 in BMC Neuroscience, Ivan A. Lopez et al. found that chronic fetal exposure to 25 ppm carbon monoxide (CO) permanently damaged rat brain cells through oxidative stress, leading to a decrease in proteins essential for proper functioning. The authors say this exposure simulates the potential CO exposure of a human fetus whose mother is a “mild to modest” smoker. Other indoor CO exposure sources include gas appliances, fireplaces, and attached garages. There are no EPA standards for CO in indoor air.Better Oversight for Bottled WaterGiven rising consumption of bottled water, the Government Accountability Office (GAO) evaluated the extent and strength of FDA regulations for this product. In June 2009, the GAO reported that FDA standards generally reflect those of the EPA except in the case of di(2-ethylhexyl) phthalate, a compound used to make plastic bottles, for which the FDA has no standard. The GAO recommended that the FDA issue a standard or publish reasons for not doing so, and that water bottlers provide more labeling information for consumers on the quality and safety of their products. Currently, companies (unlike water utilities) are not required to disclose positive tests for contaminants.FiguresReferencesRelatedDetails Vol. 117, No. 8 August 2009Metrics About Article Metrics Publication History Originally published1 August 2009Published in print1 August 2009 Financial disclosuresPDF download License information EHP is an open-access journal published with support from the National Institute of Environmental Health Sciences, National Institutes of Health. All content is public domain unless otherwise noted. Note to readers with disabilities EHP strives to ensure that all journal content is accessible to all readers. However, some figures and Supplemental Material published in EHP articles may not conform to 508 standards due to the complexity of the information being presented. If you need assistance accessing journal content, please contact [email protected]. Our staff will work with you to assess and meet your accessibility needs within 3 working days.

Evaluation of microbiological and chemical parameters during wastewater Sludge and Sawdust Co-composting

Environmental specialists classified sewage sludge as a hazardous waste because of high organic compounds and pathogenic microorganisms. Therefore sewage sludge should be stabilized before disposal. Composting is an effective and economical method to stabilize sewage sludge. The object of this study is determining the optimum conditions of co- composting of dewatered sewage sludge and sawdust. Pilot scale studywas performed in Isfahan municipal wastewater treatment plant. To perform this study, the dewatered sewage sludge with humidity between 78-82 percent was mixed with sawdust. Turning over did once a week for aeration. Temperature was monitored at different depths daily. Other parameters such as N, C, organic matters, pH, heavy metals, total and fecal Coliform and Salmonella were determined three times a week. The results of this study showed that after about 15th days, temperature of the mixture reached up to 55 oC, and was stabled for fifteen days. Humidity, organic matter, organic carbon and C/N ratio of the mixture decreased during of the study, due to increasing the temperature. Also organic matter and humidity mainly decreased in thermophilic phase. The number of total and fecal coliforms and also Salmonella decreased to A class standards of U.S. EPA at the end of the operation. The result indicated that co-composting of sewage sludge with sawdust is a reliable and simple method to schedule, with high flexibility and low odor production. Organic compounds and pathogenic microorganisms reduced and EPA standards were met during this method. @ JASEM

Nitrous oxide emissions from light duty vehicles

Nitrous oxide (N 2O) emissions measurements were made on light duty gasoline and light duty diesel vehicles during chassis dynamometer testing conducted at the Environment Canada and California Air Resources Board vehicle emissions laboratories between 2001 and 2007. Per phase and composite FTP emission rates were measured. A subset of vehicles was also tested using other driving cycles to characterize emissions as a function of different driving conditions. Vehicles were both new (<6500 km) and in-use (6500–160,000 km) and were tested on low sulfur gasoline (<30 ppm) or low sulfur diesel (<300 ppm). Measurements from selected published studies were combined with these new measurements to give a test fleet of 467 vehicles meeting both US EPA and California criteria pollutant emissions standards between Tier 0 and Tier 2 Bin 3 or SULEV. Aggregate distance-based and fuel-based emission factors for N 2O are reported for each emission standard and for each of the different test cycles. Results show that the distinction between light duty automobile and light duty truck is not significant for any of the emission standards represented by the test fleet and the distinction between new and aged catalyst is significant for vehicles meeting all emission standards but Tier 2. This is likely due to the relatively low mileage accumulated by the Tier 2 vehicles in this study as compared to the durability requirement of the standard. The FTP composite N 2O emission factors for gasoline vehicles meeting emission standards more stringent than Tier 1 are substantially lower than those currently used by both Canada and the US for the 2005 inventories. N 2O emission factors from test cycles other than the FTP illustrate the variability of emission factors as a function of driving conditions. N 2O emission factors are shown to strongly correlate with NMHC/NMOG emission standards and less strongly with NO X and CO emission standards. A review of several published reports on the effect of gasoline sulfur content on N 2O emissions suggests that additional research is needed to adequately quantify the increase in N 2O emissions as a function of fuel sulfur.

The pollution characteristics of odor, volatile organochlorinated compounds and polycyclic aromatic hydrocarbons emitted from plastic waste recycling plants

Plastic waste treatment trends toward recycling in many countries; however, the melting process in the facilities which adopt material recycling method for treating plastic waste may emit toxicants and cause sensory annoyance. The objectives of this study were to analyze the pollution characteristics of the emissions from the plastic waste recycling plants, particularly in harmful volatile organochlorinated compounds, polycyclic aromatic hydrocarbons (PAHs), odor levels and critical odorants. Ten large recycling plants were selected for analysis of odor concentration (OC), volatile organic compounds (VOCs) and PAHs inside and outside the plants using olfactometry, gas chromatography–mass spectrometry and high performance liquid chromatography–fluorescence detector, respectively. The olfactometric results showed that the melting processes used for treating polyethylene/polypropylene (PE/PP) and polyvinyl chloride (PVC) plastic waste significantly produced malodor, and the odor levels at downwind boundaries were 100–229 OC, which all exceeded Taiwan’s EPA standard of 50 OC. Toluene, ethylbenzene, 4-methyl-2-pentanone, methyl methacrylate and acrolein accounted for most odors compared to numerous VOCs. Sixteen organochlorinated compounds were measured in the ambient air emitted from the PVC plastic waste recycling plant and total concentrations were 245–553 μg m −3; most were vinyl chloride, chloroform and trichloroethylene. Concentrations of PAHs inside the PE/PP plant were 8.97–252.16 ng m −3, in which the maximum level were 20-fold higher than the levels detected from boundaries. Most of these recycling plants simply used filter to treat the melting fumes, and this could not efficiently eliminate the gaseous compounds and malodor. Improved exhaust air pollution control were strongly recommended in these industries.

A note on the 2008 EU standards for particulate matter

In the spring of 2008, the EU decided on the future PM regulations. In this note we first compare existing regulations for PM10 with updated regulations for PM10; then we discuss the decisions on PM2.5; and finally we compare the new EU regulations with US EPA standards for PM2.5. The conclusions are that PM10 regulations have been somewhat relaxed despite the fact that the numerical values of the Limit Values have not changed; that the annual PM2.5 Limit Value is at the upper end of exposure response curves from major epidemiological studies, and hence not protective of public health as major adverse effects on health have been observed at levels well below the adopted PM2.5 limit value; that the newly introduced instrument of the ‘exposure concentration obligation’ is unlikely to improve this; that the US EPA National Ambient Air Quality Standards for PM2.5 are lower than the EU limit values; and that, contrary to what is often suggested, the EU requirements for assessing compliance with the Limit Value for PM2.5 are not more stringent than the US EPA requirements for assessing compliance with the annual and 24 h PM2.5 National Ambient Air Quality Standards.

New EPA standards would cut amount of lead in the air, but not enough to protect the public

New EPA standards would cut amount of lead in the air, but not enough to protect the public

Uranium in Drinking Water: Low Dose Acts as Endocrine Mimic

Uranium, the heaviest naturally occurring element, is well known as a radioactive toxicant capable of damaging the kidneys and DNA. A new study has shown for the first time that uranium also acts as an estrogen mimic in mice at concentrations below the U.S. EPA’s safety limit of 30 μg/L in drinking water [EHP 115:1711–1716; Raymond-Whish et al.]. Other metals, including arsenic, cadmium, lead, and mercury, also are known estrogen mimics. The researchers manipulated the reproductive status of female mice in several ways. They exposed one group of immature female mice to uranium as they matured, a second group of mature female mice to uranium at environmentally relevant concentrations for 30 days prior to breeding and through gestation, and a third group of female mice to uranium immediately after their ovaries were removed. In a fourth group, they removed the ovaries of female mice, then exposed subgroups of this cohort to either uranium or the synthethic estrogen diethylstilbestrol (DES) alone or in combination with the antiestrogen ICI 182,780. All uranium exposures were via the mice’s drinking water at concentrations of 0.5 μg/L–60.0 mg/L. Uranium had estrogen-like effects at varying dose ranges throughout the suite of experiments. In the first group, exposure resulted in fewer primary and more secondary ovarian follicles among adult females. In the second group, female pups of exposed dams had significantly fewer small primary ovarian follicles. The researchers conjecture that this primary-to-secondary follicle ratio may lead to fewer ovulated eggs and early-onset menopause. In the ovariectomized mice, the researchers found higher uterine weights and accelerated vaginal opening (indicators of earlier puberty onset). In addition, estrogenic activity was blocked in the mice exposed to ICI 182,780 after DES or uranium exposure. The current study is of immediate relevance to the Navajo Nation of Arizona and New Mexico, where many rural Navajo water supplies currently contain uranium at concentrations exceeding the U.S. EPA standard. The uranium boom of the 1950s and 1960s left thousands of abandoned mine sites and derelict milling operations on Navajo lands. Uranium mining has been banned there, but there are active efforts to revive uranium mining in the Navajo town of Crownpoint, New Mexico. The findings may also soon apply to other populations living amid the uranium boom now under way in central Colorado, Canada, Australia, and elsewhere.

Assessment of Contamination Characteristics in Waters of the Kütahya Plain, Turkey

AbstractThe contamination characteristics of surface water and groundwaters in the Kütahya plain, one of the most important plains in Turkey, are investigated. In this region, waters of the Porsuk river are used by thousands of people in the city of Eskisehir. A total of 44 spring, river and groundwater samples collected from the region were analyzed for their Ag, Al, As, B, Br, Ca, Cd, Cu, Fe, Hg, K, Li, Mg, Na, Ni, P, Pb, S, U and Zn contents. A wastewater treatment plant, solid waste disposal site, industrial areas, agricultural activities and aquifers composed of metalliferous rocks are the main pollutants in the study area. It was determined that various elements in spring, river and groundwaters result in different degrees of contamination. According to EPA (2003) standards, all the waters exceed the maximum contaminant level. These waters are carried by the Porsuk river to the Eskisehir basin, and the resulting situation creates a serious health problem for people who live in the cities of Kütahya and Eskisehir.

Qualitative monitoring of tertiary treated wastewater reuse extensive distribution system: total coliforms number and residual chlorine concentration

During a 5-month summer period, samples of tertiary treated wastewater flowing in an extensive distribution system composed of storage tanks and pipes were collected at 2-week intervals, from 21 different sampling points, including the exit from the wastewater treatment plant (WWTP). The WWTP producing this effluent treated one of the most popular European tourist resorts on the north coast of the island of Crete, at the southernmost point of Greece. The average summer equivalent population treated by the plant exceeded 50,000, falling to under 5,000 in the winter. The samples were analyzed for total coliforms number (TC in cfu / 100 mL) and residual chlorine concentration (RCHL in mg/L). In almost 60% of the samples the TC number was so large that it could be safe to suggest that the WWTP and distribution system failed to reach the EPA standards for wastewater reuse for tree irrigation (faecal coliforms ≤ 200 cfu/100 mL and RCHL < 1 mg/L) due mainly to inflow and septage handling, above designed limits. The licensing operational and reuse standards were set in TC ≤ 500 cfu/100 mL, where 76% of the analyzed samples recorded larger values. It was also estimated that in 14% of the samples the wastewater quality failed to reach even the less strict WHO standards of FC ≤ 1.000 cfu/100 mL. When chlorination was properly adjusted the effluent quality was improved (last three sets of samplings for each collection point), helped by the WWTP inflow decrease. As a result the values recorded in all tanks and collectors were also improved. However, even then, the required licensing standards were randomly and barely achieved. This suggests that specific wastewater quality standard at the exit of a WWTP do not guarantee that the wastewater will still retain these characteristics at its final application point.

Modification of Activated Carbon by Polyaniline for Enhanced Adsorption of Aqueous Arsenate

A raw granular activated carbon (RGAC) is modified by polyaniline to improve arsenate adsorption. It is found that the modification does not change the specific surface area. The content of the aromatic ring structures and nitrogen-containing functional groups on the modified GAC (MGAC) is increased. The surface positive charge density is dramatically increased in acidic solutions. The adsorption of As(V) onto both sorbents is highly pH dependent. The modification broadens the optimal pH range for the arsenate adsorption: pH of 3.0−6.8 and 4.0−6.6 for the MGAC at initial arsenic concentrations of 0.15 and 8.0 mg L-1 vs pH 6.0 and 6.5 for the RGAC at the same concentrations. The maximum adsorption capacity at an optimal pH of 5.5 is enhanced by 84%. The MGAC is able to greatly remove the arsenic at a trace level; the concentration of treated solution is far below the U.S. EPA standard. The presence of humic acid does not have a great impact on the arsenic adsorption dynamics. The modification significantly enhances the adsorption of humic acid onto the carbon. X-ray photoelectron spectroscopy analysis demonstrates that the arsenate is reduced to arsenite during the process. A fixed bed is able to reduce arsenate concentrations ranging from 120 to 1910 ppb to less than 10 ppb. The column adsorption behavior by the MGAC can well be described by a fixed-bed model.

The Chosen ONES: Awards Fund Young Investigators

A major goal of the 2006 NIEHS Strategic Plan encompasses the institute’s desire to “recruit and train the next generation of environmental health scientists.” To begin to achieve that goal, the NIEHS has unveiled a new annual grants program called the Outstanding New Environmental Scientist (ONES) Award. The five-year grants are designed to identify, encourage, inspire, and support outstanding investigators early in their careers, who have not yet received their first R01 grant. The first ONES grants, totaling $3.6 million, were awarded in September 2006 to eight promising young scientists chosen from more than 70 applicants through a rigorous application, review, and interview process. The program is the brainchild of NIEHS director David Schwartz, who has been concerned for some time about the loss of promising young scientific talent from the field for lack of support. “As a faculty member at Duke,” he says, “I found that the individuals who were particularly vulnerable in terms of their career development were those at that transitional stage between mentored and independent research, and that many very bright, creative people simply were not supported in ways that enhanced their career development.” Schwartz says the awards are also intended to help attract innovative young investigators to the NIEHS and the environmental health sciences, as well as to support the institutions that are helping new scientists develop their careers. The program’s long-term impact on the field, in terms of both the science and the scientists, could be significant. “These individuals represent very promising early career trajectories that are likely to have a substantial effect on environmental health sciences, and hopefully will evolve into the leaders in the field in the future,” says Schwartz. To ease that tricky early-career transition, ONES grantees are encouraged to establish and meet annually with an advisory committee comprising senior experts in their disciplines. According to Pat Mastin, chief of the NIEHS Cellular, Organ, and Systems Pathobiology Branch, who helped coordinate the initial ONES process, the grants represent a hybrid between mentored career development awards and independent R01 grants. “We think the young investigators should continue to be mentored,” Mastin says. “So we encouraged them to identify not a specific mentor, but an advisory committee, to give not only scientific advice but also career path advice.” The grantees recognize and appreciate the value of this hybrid approach to mentoring. “It gives us access to people we wouldn’t normally be interacting with,” says ONES grantee Thomas Begley, an assistant professor in the Department of Biomedical Sciences at the University at Albany State University of New York. “Having a mechanism to ensure that will promote good science on my end, and also will help me network with others in the field.” Grantee Patricia Opresko, an assistant professor in the Department of Environmental and Occupational Health at the University of Pittsburgh, agrees. “The grant has funds that will allow the four investigators on my advisory committee to come to Pittsburgh and meet with me once a year to focus on my project and offer their ideas, insight, input, and criticisms,” she says. “It adds an additional layer of mentoring that is really critical for a young investigator’s development.”

Varied forms of palygorskite and sepiolite from different geologic systems

Both palygorskite and sepiolite occur as sheets in tension fracture zones, fault zones, and caves in rock strata, as well as forming strata in alluvial terraces. The sheets of fibrous clays were commonly named mountain leather or mountain cork. The fibrous clays occur in geologic host rock systems of Paleozoic and Mesozoic ages as well as Quaternary age. The analyzed palygorskites represent a continuous series with Al 2O 3 contents ranging from 16.3 wt.% to 4.8 wt.% and (110) XRD peaks from 10.30 Å to 10.57 Å. When less than about 8 wt.% Al 2O 3 is present secondary NIR Mg related OH bands may be observed along with the palygorskite spectra. The analyzed sepiolites have (110) XRD d-values ranging from 12.03 Å to 12.26 Å. The latter is an Fe-sepiolite (xylotile). DTA analyses show that the palygorskite exotherm temperatures form a linear function with the Al 2O 3 contents, from 1045 °C at 16.3 wt.% to 880 °C at 4.8 wt.% Al 2O 3. The fibrous clays can readily adsorb considerable amounts of metals, such as Pb, As, and Cd. The amounts held can be used for determining whether the clays are classified as hazardous materials, on the basis of U.S. EPA and California State standards.

Sensitivity of ozone to summertime climate in the eastern USA: A modeling case study

The goal of this modeling study is to determine how concentrations of ozone respond to changes in climate over the eastern USA. The sensitivities of average ozone concentrations to temperature, wind speed, absolute humidity, mixing height, cloud liquid water content and optical depth, cloudy area, precipitation rate, and precipitating area extent are investigated individually. The simulation period consists of July 12–21, 2001, during which an ozone episode occurred over the Southeast. The ozone metrics used include daily maximum 8 h average O 3 concentration and number of grid cells exceeding the US EPA ambient air-quality standard. The meteorological factor that had the largest impact on both ozone metrics was temperature, which increased daily maximum 8 h average O 3 by 0.34 ppb K −1 on average over the simulation domain. Absolute humidity had a smaller but appreciable effect on daily maximum 8 h average O 3 (−0.025 ppb for each percent increase in absolute humidity). While domain-average responses to changes in wind speed, mixing height, cloud liquid water content, and optical depth were rather small, these factors did have appreciable local effects in many areas. Temperature also had the largest effect on air-quality standard exceedances; a 2.5 K temperature increase led to a 30% increase in the area exceeding the EPA standard. Wind speed and mixing height also had appreciable effects on ozone air-quality standard exceedances.

Arsenic Removal in Drinking Water Sources by Reverse Osmosis Units in Real Life Scenarios

P-226 Abstract: Ingested inorganic arsenic (InAs) causes cancer of the skin, bladder, and lung, and millions of people in the US and worldwide are exposed to drinking water containing this known carcinogen. A new US regulatory standard for drinking water InAs in public water of 10-ug/L has recently taken effect, but this does not apply to private domestic wells. According to the USGS, 15% of the US population (approximately 45 million people) receive drinking water from private domestic wells. Reverse osmosis water filtration units are commonly used by owners of private domestic wells to reduce arsenic concentrations, but may not always reduce arsenic concentrations to safe levels. Several reports have evaluated the effectiveness of reverse osmosis filtration units in laboratory settings. However, because of poor maintenance, improper use, limited lifespan, or other issues, the effectiveness of these filters in real-life situations may differ from that in laboratory testing. In this study, we evaluated the effectiveness of RO filters in removing arsenic in actual use residential settings. Wells were randomly selected; a sample was collected at a source before reverse osmosis filtration, usually a hose next to the home. Another sample was collected at the subject's primary drinking water source after being run through reverse osmosis filtration under normal use conditions, in most homes this was the faucet in the kitchen. Instrumental analysis was performed by automated flow injection using borohydride reduction and continuous arsine detection by atomic fluorescence spectroscopy (AFS). In this study, pre- and postfiltration arsenic concentrations were measured in 19 homes using reverse osmosis units to filter domestic well water with high arsenic concentrations. Our analysis of pre- and postfiltrations arsenic levels for each filter are being finalized and will be presented at the conference. However, preliminary data suggest that while RO systems in several homes remove a substantial fraction of arsenic in the source water, arsenic levels in some homes were not be reduced to levels which meet US regulatory standards. And, in a few homes, post filtration arsenic levels remain at levels near those associated with increased of cancer in some studies. Although this data may not be generalizable to all reverse osmosis units in actual use, these data provide evidence that a substantial fraction may not be reducing arsenic concentrations to safe levels. This a public health concern because many individuals in this area rely solely on private well water for drinking, and maybe be unknowingly at risk of exposures at levels above EPA standard.

Assessment and Control of Metals Exposures in the Residential Environment During the Early Stages of Life

WS4-04 Abstract: Metals such as lead, arsenic, and cadmium are common contaminants at many hazardous waste sites and may pose a particular risk to young children due to differences in behavior and their increased susceptibility for neurodevelopmental impairment. Few studies have collected systematic data on concurrent exposure to multiple metals during the early stages of life or accounted for potential interactions. We conducted a longitudinal, multimedia exposure assessment study at the Tar Creek Superfund Site, a mining-related hazardous waster site contaminated by metals in mining tailings and populated by many residents of Native American descent. The objective was to evaluate the relationship between exposures to metals in the residential environment and biomarkers of absorbed metals dose at various stages of development to characterize pathways and sources of exposure. The residential environments of 50 children under 1 year of age were inspected and sampled twice at 6-month intervals. Thirty-six percent of homes lived within the Superfund site boundaries and 14% lived in 2 high-risk towns. From each home, we collected samples of respirable, airborne particles (PM2.5), house dust, drinking water, yard soil, and food to be analyzed for lead, zinc, arsenic, iron, cadmium, copper, and manganese. Metal concentrations in ambient air were assessed at 3 fixed sites and a cascade impactor was used to separate <37 μm fraction into smaller-sized particles. Although ambient air concentrations for PM10 and PM2.5 were less than the EPA standards, metals concentrations in smaller (0.1–1.0 μm) particles were approximately 3 times higher than average (<37 μm) -sized particles. In addition to the thousands of tons of mine tailings piles scattered throughout the area, the “chat,” or the smaller particles of mine tailings, has been used as gravel base for roads, parking lots, and concrete slabs in new home construction. Based on the results of an interview, 20% of residents responded that chat had been used in the foundations of their homes, 26% reported knowing of chat used in neighborhood roads, and over 40% said that chat was used in their home's driveway. This information will be used to design, implement, and evaluate a culturally based risk assessment and nutritional, behavioral, and environmental intervention strategy to reduce children's potential in-home exposures. Results from this research can be used to better understand multimedia exposure pathways and to develop practical approaches for studying complex metals mixtures in the residential environment.

Simulation of Children Exposure to NO2 and PM10 in Bologna, Italy

MS8-07 Introduction: Personal exposures studies enable to identify high-exposed population members and major contributions to personal exposures. The study focused on exposures of school children, which have increasing importance in public health evaluations due to their susceptibility and their importance in environment-induced reductions in quality of life. Material and Methods: We simulated exposure to NO2 and PM10 of 333 children attending 2 primary schools in a densely populated and traffic-dominated area in Bologna. Time-weighted annual mean personal exposures were estimated on the basis of residential indoor, school indoor, outdoor, and traffic concentrations. Exposure was derived by typical hourly concentration profiles in each microenvironment for 3 typical days: schooling and weekend days during the school year and summer days using time activity data from existing children surveys. The reference period for the simulations was June, 1, 2004, to May, 31, 2005. The infiltration factors were derived from the EXPOLIS study. Results: Simulated outdoor concentrations were higher than the experimental ones for approximately 30% for NO2 and for approximately 10% for PM10. Children's NO2 and PM10 mean exposures were, respectively, approximately 50% and 40% lower than monitoring station annual means. Mean NO2 personal exposures in a typical winter school day were approximately 20% higher than exposures in a typical weekend winter day and approximately 30% higher than in a typical summer day. Similar results were found for PM10 with the percentages equal to 40% and 50%, respectively. The exposure variability among the children was quite high: some children were exposed approximately at 2 times higher levels than the less-exposed children. Home and school indoor concentrations are the main determinants of the total exposures. Discussion and Conclusions: The AQ model used to estimate outdoor concentrations performed well in simulating annual averages. Local experimental data on personal exposures and measurements of infiltration factors, indoor sources, and in-traffic exposures are needed to evaluate the model performances. Exposure simulations will be applied in the near future to estimate reduction in children exposure due to traffic periodic limitations adopted by local authorities because of frequent violations of the air pollution limit values. centrations for PM10 and PM2.5 were less than the EPA standards, metals concentrations in smaller (0.1–1.0 μm) particles were approximately 3 times higher than average (<37 μm) -sized particles. In addition to the thousands of tons of mine tailings piles scattered throughout the area, the “chat,” or the smaller particles of mine tailings, has been used as gravel base for roads, parking lots, and concrete slabs in new home construction. Based on the results of an interview, 20% of residents responded that chat had been used in the foundations of their homes, 26% reported knowing of chat used in neighborhood roads, and over 40% said that chat was used in their home's driveway. This information will be used to design, implement, and evaluate a culturally based risk assessment and nutritional, behavioral, and environmental intervention strategy to reduce children's potential in-home exposures. Results from this research can be used to better understand multimedia exposure pathways and to develop practical approaches for studying complex metals mixtures in the residential environment.

Suspensions of fluor-containing nanoparticles for quantifying β−-emitting radionuclides in non-hazardous media

Nanoparticles containing scintillants were prepared from oil-in-water microemulsions in which styrene-divinylbenzene comprised the oil phase. Primary and secondary fluors [2,5-diphenyloxazole and 1,4-bis(2-methylstyryl) benzene] were dissolved in the oil phase, which was emulsified with dodecyl trimethylammonium bromide or sodium dodecyl sulfate before polymerization by the addition of sodium persulfate. The resulting suspension qualified as non-hazardous waste by testing against US EPA standards for reactivity, pH, ignitability, and toxicity characteristic leaching.14C-glycerol was added to the aqueous nanoparticle suspension and to a conventional organic scintillation cocktail, and the relative efficiency of detection was obtained by liquid scintillation counting. The results were compared with a mathematical model that predicted the effect of particle size and concentration on the probability of an emitted β− particle interacting with a suspended particle. The use of these nanoparticle suspensions represents an opportunity to reduce mixed low-level radioactive hazardous waste generated by liquid scintillation counting.

Vapor Leak Detection for an Underground Storage Tank System

This paper presents a mathematical model for the pressure inside the vapor space of an underground storage tank (UST). Using mass balances based on dispensing activities, vapor recovery, evaporation, leaks, and the safety vent, the model resulted in a system of nonlinear differential equations with unknown parameters, leak rate and evaporation rate. Given the leak rate and evaporation rate, the pressure inside the UST can be obtained by solving the system of differential equations numerically. Given the pressure inside a UST over a period of time, one can find the evaporation and leak rates such that the calculated pressure from our model best fits the given pressure data. This optimal value of leak rate can allow us to determine whether the UST system is leaking and if the leak rate is above the EPA standard. Numerical results and statistical analysis of our model are also presented.

Trace analysis of hydrogen sulfide by monitoring As(III) at a poly( l-lactide) stabilized gold nanoparticles modified electrode

An indirect electrochemical approach for the determination of sulfide by measuring the inhibited oxidation current of As(III) in HCl medium using a poly( l-lactide) stabilized gold nanoparticles modified screen-printed electrode (designated as PLA-Au NP/SPE) is described in this work. The PLA-Au NP/SPE is applied effectively to detect As(III) in HCl medium and can be tolerable from the interference of Cu, Cd, Fe, Zn, Mn and Ni and hence provides a direct and selective detection method for As(III) in natural waters. An substantial decrease in the oxidation peak current of As(III) is observed in the presence of sulfide due to the formation of As 2S 3 complex. Surface analysis by XPS together with electrochemical and Raman spectroscopic characterization were used to elucidate the detection mechanism. Under the optimal experimental conditions, a calibration plot with a wide linear range up to 700 μM was achieved with a detection limit ( S/ N = 3) of 0.04 μM. The sensitivity observed in present study is good enough to detect sulfide at levels lower than the current EPA standard. The proposed electrochemical approach was successfully used for the determination of sulfide in acid rain and hot spring water.

Critical components of odors in evaluating the performance of food waste composting plants

The current Taiwan government policy toward food waste management encourages composting for resource recovery. This study used olfactometry, gas chromatography–mass spectrometry (GC–MS) and gas detector tubes to evaluate the ambient air at three of the largest food waste composting plants in Taiwan. Ambient air inside the plants, at exhaust outlets and plant boundaries was examined to determine the comprehensive odor performance, critical components, and odor elimination efficiencies of various odor control engineering. Analytical results identified 29 compounds, including ammonia, amines, acetic acid, and multiple volatile organic compounds (VOCs) (hydrocarbons, ketones, esters, terpenes and S-compounds) in the odor from food waste composting plants. Concentrations of six components – ammonia, amines, dimethyl sulfide, acetic acid, ethyl benzene and p-Cymene – exceeded human olfactory thresholds. Ammonia, amines, dimethyl sulfide and acetic acid accounted for most odors compared to numerous VOCs. The results also show that the biotrickling filter was better at eliminating the concentrations of odor, NH3, amines, S-compounds and VOCs than the chemical scrubber and biofilters. All levels measured by olfactometry at the boundaries of food waste composting plants (range, 74–115 Odor Concentration (OC)) exceeded Taiwan's EPA standard of 50 OC. This study indicated that the malodor problem continued to be a significant problem for food waste recovery.