Emissions of speciated volatile organic compounds (VOCs), including mobile source air toxics (MSATs), were measured in vehicle exhaust from three light-duty spark ignition vehicles operating on summer and winter grade gasoline (E0) and ethanol blended (E10 and E85) fuels. Vehicle testing was conducted using a three-phase LA92 driving cycle in a temperature-controlled chassis dynamometer at two ambient temperatures (-7 °C and 24 °C). The cold start phase and cold ambient temperature increased VOC and MSAT emissions dramatically by up to several orders of magnitude compared to emissions during other phases and warm ambient temperature testing, respectively. As a result, calculated ozone formation potentials during the cold starts were significantly higher during cold temperature tests by 7 to 21 times the warm temperature values. The use of E85 fuel generally led to substantial reductions in hydrocarbons and increases in oxygenates such as ethanol and acetaldehyde compared to E0 and E10 fuels. However, the VOC emissions from E0 and E10 fuels were not significantly different. Cold temperature effects on cold start MSAT emissions varied by individual MSAT compound, but were consistent over a range of modern spark ignition vehicles.
The present document describes key discussion points and outcomes of a Society of Toxicology (SOT) Contemporary Concepts in Toxicology (CCT) Workshop, entitled FutureTox III1,2 that was held in Crystal City, Virginia, November 19-20, 2015. The workshop built on the many lessons learned from the first 10 years of TT21 and the first two workshops in the FutureTox series (for summary of FutureTox II see (Knudsen et al., 2015); for summary of FutureTox I see (Rowlands et al., 2014)). FutureTox III was attended in person and via webcast by more than 300 scientists from government research and regulatory agencies, research institutes, academia, and the chemical and pharmaceutical industries in Europe, Canada, and the United States. The meeting materials for FutureTox III, currently available to meeting registrants at http://www.toxicology.org/events/shm/cct/meetings.asp#upcoming-pnl-open, will be open to the public on November 29, 2016. At this workshop, participants reviewed and discussed the state of the science in toxicology and human risk and exposure assessment with a focus on moving TT21 science into the arena of regulatory decision-making.
Regulatory non-clinical safety testing of human pharmaceutical compounds typically requires embryo fetal developmental toxicity (EFDT) testing in two species, (one rodent and one non-rodent, usually the rat and the rabbit). The question has been raised whether under some conditions EFDT testing could be limited to one species, or whether the need for testing in a second species could be decided on a case by case basis. As part of an RIVM/CBG-MEB/HESI/US EPA consortium initiative, we built and queried a database of 379 EFDT studies conducted for marketed and non-marketed pharmaceutical compounds. The animal models (rat and rabbit) were assessed for their potential for adverse developmental and maternal outcomes. The database was analyzed for the prevalence of EFDT incidence and the nature and severity of adverse findings in the two species. Some manifestation of EFDT in either one or both species (rat and rabbit) was demonstrated for 282 compounds (74%), and EFDT was detected in only one species (rat or rabbit) in almost a third (31%, 118 compounds), with approximately 58% rat and 42% rabbit studies identifying an EFDT signal among the 379 compounds tested. For 24 compounds (6%), fetal malformations were observed in one species (rat or rabbit) in the absence of any EFDT in the second species. In general, growth retardation, fetal variations, and malformations were more prominent in the rat, whereas embryo-fetal death was observed more often in the rabbit. Discordance across animal species may be attributed to factors such as maternal toxicity, study design differences, pharmacokinetic differences, and pharmacologic relevance of species. Discussion of the implications of these findings for EFDT testing strategies of pharmaceuticals awaits an accompanying study considering systemic exposure comparison between species. The current analysis based on the nature and severity of EFDT suggests that in general both species are equally sensitive on the basis of an overall EFDT LOAEL comparison, but selective toxicity in one species is not uncommon. Also, there appear to be species differences in the prevalence of various manifestations of EFDT (i.e., embryo-fetal death, growth retardation and dysmorphogenesis) between rat and rabbit, suggesting that the use of both species has a higher probability of detecting developmental toxicants than either one alone.
1-Bromopropane (CASRN 106-94-5): or 1-BP is a volatile organic chemical that is considered moderately persistent in the environment but does not have the potential to bioaccumulate in fish or other animals. The majority of the 1-BP production volume (~ 47%) is used as a vapor degreaser for optics electronics, plastics, and metals. 1-BP also is used as an aerosol solvent in cleaning products, as a spray fixative in arts and crafts, and as a spot cleaner in various industrial/commercial/consumer sectors.
Focus of the Risk Assessment: The assessment will focus on uses of 1-BP in commercial (i.e., vapor degreasing, spray adhesives, and dry cleaning) and consumer applications (i.e., aerosol solvent cleaners and spray adhesives). Given the range of endpoints (i.e., cancer, non-cancer; the latter includes potential effects on the developing fetus), susceptible populations are expected to include adults (including pregnant women) in commercial uses and children (as bystanders) and adults of all ages (including pregnant women) for consumer uses. Thus, the assessment will focus on all humans/lifestages.
EPA has made many recent advances in high throughput bioactivity testing. However, concurrent advances in rapid, quantitative prediction of human and ecological exposures have been lacking, despite the clear importance of both measures for a risk-based approach to prioritizing and screening chemicals. A recent report by the National Research Council of the National Academies, Exposure Science in the 21st Century: A Vision and a Strategy (NRC 2012) laid out a number of applications in chemical evaluation of both toxicity and risk in critical need of quantitative exposure predictions, including screening and prioritization of chemicals for targeted toxicity testing, focused exposure assessments or monitoring studies, and quantification of population vulnerability. Despite these significant needs, for the majority of chemicals (e.g. non-pesticide environmental compounds) there are no or limited estimates of exposure. For example, exposure estimates exist for only 7% of the ToxCast Phase II chemical list. In addition, the data required for generating exposure estimates for large numbers of chemicals is severely lacking (Egeghy et al. 2012).
Watershed Management Optimization Support Tool (WMOST) is a software application designed tofacilitate integrated water resources management across wet and dry climate regions. It allows waterresources managers and planners to screen a wide range of practices across their watershed or jurisdictionfor cost-effectiveness and environmental and economic sustainability. WMOST allows users to select up to 15stormwater management practices, including traditional grey infrastructure, green infrastructure, and otherlow impact development practices.
The role of coastal wetlands in ameliorating the plight of climate change is well documented. Per unit area, coastal wetlands are among the largest natural carbon sinks, taking up abundant carbon dioxide (CO2) and emitting minimal methane (CH4). While the role of coastal marsh vegetation in mediating CO2 and CH4 flux dynamics has been well-studied, less is known about effects that other biotic drivers, including marsh invertebrates, exert on GHG fluxes. Crabs and mollusks may directly alter soil biogeochemistry and GHG fluxes by bioturbation and deposition of nutrient-rich feces, and indirectly through impacts to vegetation. The objective of this research was to survey GHG fluxes along a gradient of fiddler crab (Uca pugnax) and ribbed mussel (Geukensia demissa) densities. Surveys were performed in a Rhode Island salt marsh at randomly-chosen points in both the Spartina alterniflora-vegetated low marsh and the unvegetated creek bank. During the peak growing season, GHG (CO2 and CH4) fluxes and S. alterniflora, live and dead mussel, and crab burrow densities were measured. GHG fluxes differed substantially between the S. alterniflora marsh and creek bank, with greater CO2 uptake and CH4 emission in the S. alterniflora marsh than along the creek bank. In the S. alterniflora marsh, Spearman’s Correlation Analysis revealed a significant positive correlation between density of dead mussels and CH4 emission. However, none of the measured variables correlated with CH4 fluxes on the creek bank. Though preliminary, results of this experiment underscore both the spatial variability of coastal marsh GHG fluxes and the potential for distinct drivers to mediate fluxes across the marsh landscape.
Occupancy models are used extensively to assess wildlife-habitat associations and to predict species distributions across large geographic regions. Occupancy models were developed as a tool to properly account for imperfect detection of a species. Current guidelines on survey design requirements for occupancy models focus on the number of sample units and the pattern of revisits to a sample unit within a season. We focus on the sampling design or how the sample units are selected in geographic space (e.g., stratified, simple random, unequal probability, etc). In a probability design, each sample unit has a sample weight which quantifies the number of sample units it represents in the finite (oftentimes areal) sampling frame. We demonstrate the importance of including sampling weights in occupancy model estimation when the design is not a simple random sample or equal probability design. We assume a finite areal sampling frame as proposed for a national bat monitoring program. We compare several unequal and equal probability designs and varying sampling intensity within a simulation study. We found the traditional single season occupancy model produced biased estimates of occupancy and lower confidence interval coverage rates compared to occupancy models that accounted for the sampling design. We also discuss how our findings inform the analyses proposed for the nascent North American Bat Monitoring Program and other collaborative synthesis efforts that propose harnessing disparate data sources into a single modeling framework.
Epidemiologic studies have shown associations between air pollution concentrations measured at central-site ambient monitors and adverse health outcomes. Using central-site concentrations as exposure surrogates, however, can lead to exposure errors due to time spent in various indoor and outdoor microenvironments (ME) with pollutant concentrations that can be substantially different from central-site concentrations. These exposure errors can introduce bias and incorrect confidence intervals in health effect estimates, which diminish the power of such studies to establish correct conclusions about the exposure and health effects association. The significance of this issue was highlighted in the National Research Council (NRC) Report “Research Priorities for Airborne Particulate Matter”, which recommends that EPA address exposure error in health studies. To address this limitation, we developed MicroTrac, an automated classification model that estimates time of day and duration spent in eight ME (indoors and outdoors at home, work, school; inside vehicles; other locations) from personal global positioning system (GPS) data and geocoded boundaries of buildings (e.g., home, work, school). MicroTrac has several innovative design features: (1) using GPS signal quality to account for GPS signal loss inside certain buildings, (2) spatial buffering of building boundaries to account for the spatial inaccuracy of the GPS device, and (3) temporal buffering of GPS position to account for GPS signal reflections that occur from nearby structures. Disseminating MicroTrac to external researchers will help support additional applications of MicroTrac. To further disseminate MicroTrac, we developed a User Guide and a standalone program that requires no specialized software.
Approximately 500,000 abandoned mines across the U.S. pose a considerable, pervasive risk to human health and the environment. World-wide the problem is even larger. Lime, organic matter, biosolids and other amendments have been used to decrease metal bioavailability in contaminated mine wastes and to promote the development of a mine waste stabilizing plant cover. The demonstrated properties of biochar make it a viable candidate as an amendment for remediating metal contaminated mine soils. In addition to sequestering potentially toxic metals, biochar can also be a source of plant nutrients, used to adjust soil pH, improve soil water holding characteristics, and increase soil carbon content. However, methods are needed for matching biochar beneficial properties with mine waste toxicities and soil health deficiencies. In this presentation we will report on a study in which we used mine soil from an abandoned Cu and Zn mine to develop a three-step procedure for identifying biochars that are most effective at reducing heavy metal bioavailability. Step 1: a slightly acidic extract of the mine spoil soil was produced, representing the potentially available metals, and used to identify metal removal properties of a library of 38 different biochars (e.g., made from a variety of feedstocks and pyrolysis or gasification conditions). Step 2: evaluation of how well these biochars retained (i.e., did not desorb) previously sorbed metals. Step 3: laboratory evaluation of the performance of 1%, 2.5% and 5% biochar additions (by weight) for reduction of mine soil metal bioavailability. Investigation results were used to identify specific biochar(s) and application rate(s) to reduce metal availability and aid in remediation of a specific metal contaminated soil. Results from this study are used to develop a generalized, but directed method for matching biochars to specific metal contaminated soils for the purpose of reducing metal availability.
Students will gather at National Geographic’s headquarters in Washington for an opportunity to speak with a NASA astronaut currently living and working aboard the International Space Station. at noon EDT Thursday, Nov. 3. The 20-minute, Earth-to-space call will air live on NASA Television and the agency’s website.
Biochar can be used as an amendment to remediate metal-contaminated mine spoils for improved site phytostabilization. For successful phytostabilization to occur, biochar amendments must improve mine spoil health with respect to plant rooting plus uptake of water and nutrients. An inappropriate biochar may negatively impact plant growth conditions resulting in poor plant establishment and growth. Matching the appropriate biochar for each mine site requires reconnaissance of spoil chemical and physical conditions and then identifying which properties need rectified to promote plant growth. A rectification hierarchy needs to be established with the primary limiting factor being addressed first, then successive limitations addressed simultaneously or thereafter. We posit that spoils at each site will have a unique chemical, physical, and biological signature that will affect plant growth. For example, some spoils may be extremely acidic, possess phytotoxic concentrations of heavy metals, or have physical conditions that limits water storage and root penetration. Quantifying these and other conditions beforehand allows for the production of designer biochar with specific characteristics tailored for specific plant growth deficiencies within each spoil. Additionally, we recommend the use of proximally located, undisturbed soils to establish spoil remediation targets. In our work, we have developed a decision-tree flow-chart that identifies salient chemical, physical and microbial characteristics needed for plant growth. Combined with our knowledge of site conditions, we can then design a biochar best suited for site-specific remediation. We also propose a framework for monitoring changes in soil conditions and health and plot their progress to gauge their improvement.
This photograph shows the first pass of Echo 1, America’s first communications satellite, over the Goldstone Tracking Station managed by NASA’s Jet Propulsion Laboratory, in Pasadena, California, in the early morning of Aug. 12, 1960. The movement of the antenna, star trails, and Echo 1 (the long streak in the middle) are visible in this image.
Threatened species’ recovery planning is applied globally to stem the current species extinction crisis. Evidence supports a key role of genetic processes, such as inbreeding depression, in determining species viability. We examined whether genetic factors are considered in threatened species recovery planning. We selected ~ 100 Species Recovery Plans from each of Europe, USA, and Australia (n=318), and reviewed three broad categories of genetic data: 1) population-genetic, 2) fitness-related, and 3) life history. We found the host country, taxonomic group to which the species belonged, and some management options to be important predictors of the inclusion of genetic factors. Notably, Species Recovery Plans from the USA were more likely to consider genetic factors, probably due to the legislative requirements. We recommend an international standard, similar to a IUCN Red List framework, of explicitly considering genetic aspects of long-term viability.
One of the major advantages of NTIA’s surveys on computer and Internet use stems from their very large sample size–approximately 53,000 households representing more than 120,000 people. This allows us to break out results by demographics like age, race, income, and education, as well as by state of residence. Today, we are launching a new feature of our Data Explorer tool enabling users to visualize NTIA’s computer and Internet use data by state, with metrics displayed in a national map.
Figure 1: Internet Use from Any Location by State
Percent of Americans Ages 3+, 1998 & 2015
December 1998 July 2015
Users can easily adjust the map to reflect different datasets, while pressing the “Play” button cycles through datasets to show how the country has changed over time. The map view is available for every metric in Data Explorer, such as use of various devices, locations of Internet use, and online activities.
Geukensia demissa, the ribbed mussel, is a useful indicator of sources of nitrogen input into coastal watersheds as it possesses a slow tissue turnover rate and is a common salt marsh species. During the summer of 2016, we sampled ribbed mussels from three New England sub-watersheds, Ocean Heights and Farm Neck sub-watershed, Massachusetts, and Greenwich Cove watershed, Rhode Island, for their nitrogen and carbon isotope signatures. We found the isotope signatures were consistent with historical isotope data from these three sites. We then determined shell length and condition index of the mussels as well as total suspended solids and particulate organic matter in the water to explain the isotopic signatures. The results provided information that suggests the nitrogen isotopic signatures from the two sub-watersheds in Massachusetts are indicative of a mix of synthetic fertilizer and wastewater. Despite upgrades to the major waste water treatment facility in the Greenwich Cove sub watershed, the mussels still contain a nitrogen isotope signature indicative of wastewater. We plan to investigate the isotope signatures of ribbed mussel food sources in the respective watersheds and the total nitrogen loads of the watersheds to more conclusively explain the isotopic signatures to provide useful information for nutrient management in coastal watersheds.
Healthy seagrass beds were once found throughout the shallow areas of Narragansett Bay, R.I. but have disappeared due to infilling, pollution and disease. In Greenwich Bay, a highly developed embayment within Narragansett Bay, Ruppia maritima has colonized an area on the northern shore historically dominated by Zostera marina. Ruppia is extremely salinity tolerant, and may also be more nutrient tolerant than Zostera. To test this hypothesis 6-week microcosm experiments were conducted in the summers of 2014 and 2015. Microcosms were renewed daily to simulate tidal flushing and the water column was dosed with a 15N tracer for the first week of the experiments. In the 2014 microcosm experiment two salinity (20, 30 ppt) and four nutrient (0, 5, 10, 30 µM inorganic N) levels were used to test the species’ relative tolerance. This experiment yielded structurally significant results for Ruppia but no significant differences were detected for Zostera. In 2015 this experiment was performed for a second time with lower salinity (5, 30 ppt) and higher nutrients (0, 30, 100, 300, 1000 µM inorganic N) in order to determine Zostera’s tolerance to nutrient and salinity stress and confirm the previously observed Ruppia results. Both species had significant structural responses to the nutrient and salinity variables. Isotopic analysis run on above-ground tissue indicated that with increasing nutrient levels δ15N in the seagrass shoots increased, suggesting that nutrients were well incorporated into the plants. Overall both species experienced diminished growth with nutrient increase, however the 2015 structural results show that Zostera was more significantly impacted than Ruppia.
There is growing interest in valuing ecosystem services provided by marsh systems. Ecosystem services represent a flow of benefits to society from the existence or functioning of the marsh. Therefore, to “put a value on” the marsh itself, or estimate a value of the natural capital, the dynamics of the marsh through time matter to its current value. For carbon sequestration and nutrient processing, this means understanding the flow of services as the marsh migrates inland due to sea-level rise. This work will combine an existing marsh migration tool, SLAAM, field observations on a transitioning marsh, and a dynamic economic valuation framework. With this conceptual model, we plan to evaluate interventions to encourage upland marsh migration as compared to the “do-nothing” scenario. There are a number of existing mash ecosystem service valuation tools, but most use a static, or possibly simple linear extrapolation of dynamics through time, to come to conclusions on the possible value of an intervention. We see a need to verify and take into account the time-paths for the purposes of ecosystem service valuation and its application to marsh systems.
Ted Meyer has made art using the body as a starting point since he was a child. Meyer, who has Gaucher’s disease, turned to art to help him get through long hospital stays and to express the distress he felt from the constant pain of his disease….
By: Suzanne B. Schwartz, M.D., M.B.A. October is National Cybersecurity Awareness Month. Proclaimed by President Obama each year, Cybersecurity Awareness Month encourages the public and industry to understand the importance of cybersecurity and to be vigilant when it comes to … Continue reading →