Monthly Archives: December 2016

Development and evaluation of a lightweight sensor system for aerial emission sampling from open area sources (Abstract)

A new sensor system for mobile and aerial emission sampling was developed for open area pollutant sources, such as prescribed forest burns. The sensor system, termed “Kolibri”, consists of multiple low-cost air quality sensors measuring CO2, CO, samplers for particulate matter with diameter of 2.5 µm or less (PM2.5), and volatile organic compounds (VOCs).

KZRV ( 16V898000 )

Dated: DEC 12, 2016 KZRV, L.P. (KZRV) is recalling certain model year 2016-2017 Venom and Durango Gold toyhaulers and fifth wheel trailers manufactured January 11, 2016, to December 2, 2016. The affected vehicles have r…

DRV ( 16V896000 )

Dated: DEC 12, 2016 DRV Suites (DRV) is recalling certain model year 2017 Full House recreational trailers, models JX450, LX410, LX450 and LX455, manufactured August 29, 2016, to November 30, 2016. The affected vehicles…

MERCEDES BENZ ( 16V899000 )

Dated: DEC 12, 2016 Mercedes-Benz USA, LLC. (MBUSA) is recalling certain model year 2013-2015 SL550, 2013-2014 SL63 AMG, 2014-2016 E350, 2014 E350 Cabriolet, E350 Coupe, 2014-2015 S550, 2015 E350 Bluetec, 2015-2016 E400,…

Small Satellite Deployed From the Space Station

A satellite is ejected from the Japan Aerospace Exploration Agency (JAXA) Small Satellite Orbital Deployer on the International Space Station on Dec. 19, 2016. The satellite is actually two small satellites that, once at a safe distance from the station, separated from each other, but were still connected by a 100-meter-long Kevlar tether.

Dose and Effect Thresholds for Early Key Events in a Mode of PPARa-Mediated Action

ABSTRACT Strategies for predicting adverse health outcomes of environmental chemicals are centered on early key events in toxicity pathways. However, quantitative relationships between early molecular changes in a given pathway and later health effects are often poorly defined. The goal of this study was to evaluate short-term key event indicators using qualitative and quantitative methods in an established pathway of mouse liver tumorigenesis mediated by peroxisome proliferator-activated receptor-alpha (PPARα). Male B6C3F1 mice were exposed for 7 days to di(2-ethylhexyl) phthalate (DEHP), di-n-octyl phthalate (DNOP), and n-butyl benzyl phthalate (BBP), which vary in PPARα activity and liver tumorigenicity. Each phthalate increased expression of select PPARα target genes at 7 days, while only DEHP significantly increased liver cell proliferation labeling index (LI). Transcriptional benchmark dose (BMDT) estimates for dose-related genomic markers stratified phthalates according to hypothetical tumorigenic potencies, unlike BMDs for non-genomic endpoints (liver weights or proliferation). The 7-day BMDT values for Acot1 as a surrogate measure for PPARα activation were 29, 370, and 676 mg/kg-d for DEHP, DNOP, and BBP, respectively, distinguishing DEHP (liver tumor BMD of 35 mg/kg-d) from non-tumorigenic DNOP and BBP. Effect thresholds were generated using linear regression of DEHP effects at 7 days and 2-year tumor incidence values to anchor early response molecular indicators and phenotypic tumor outcomes. Thresholds varied widely by marker, from 2-fold (Pdk4 and proliferation LI) to 30-fold (Acot1) induction to reach hypothetical tumorigenic expression levels. These findings highlight key issues in defining thresholds for biological adversity based on molecular changes.

MicroRNA Biomarkers of Toxicity in Biological Matrices

Biomarker measurements that reliably correlate with tissue injury and can be measured from sampling accessible biofluids offer enormous benefits in terms of cost, time, and convenience when assessing environmental and drug-induced toxicity in model systems or human cohorts. MicroRNAs (miRNAs) have emerged in recent years as a promising new type of biomarker for monitoring toxicity. Recent enthusiasm for miRNA biomarker research has been fueled by discoveries that certain miRNA species are cell-type specific and released during injury, thus raising the possibility of using biofluid-based miRNAs as a “liquid biopsy” that may be obtained by sampling extracellular fluids. As biomarkers, miRNAs demonstrate improved stability as compared to many protein markers and sequences are largely conserved across species, simplifying analytical techniques. Recent efforts have sought to identify miRNAs that are released into accessible biofluids following xenobiotic exposure, using compounds that target specific organs. While still early in the discovery phase, miRNA biomarkers will have an increasingly important role in the assessment of adverse effects of both environmental chemicals and pharmaceutical drugs. Here, we review the current findings of biofluid-based miRNAs, as well as highlight technical challenges in assessing toxicologic pathology using these biomarkers.

Biochemical Effects of six Ti02 and four Ce02 Nanomaterials in HepG2 cells

Abstract The potential mammalian hepatotoxicity of nanomaterials were explored in dose-response and structure-activity studies with human hepatic HepG2 cells exposed to between 10 and 1000 ug/ml of six different TiO2 and four CeO2 nanomaterials for 3 days. Various biochemical parameters were then evaluated to study cytotoxicity, cell growth, hepatic function and oxidative stress. Few indications of cytotoxicity were observed between 10 and 100 ug/ml. In the 300 to 1000 ug/ml exposure range a moderate to substantial degree of cytotoxicity was observed. The percent of lactic dehydrogenase released from cells was the most sensitive cytotoxicity parameter. There were four major biochemical effects observed. By far decreased activities of glucose 6-phosphate dehydrogenase was the major finding of this enzymatic study with some significant decreases observed at 10 ug/ml. In the range of 100 to 1000 ug/ml, the activities of superoxide dismutase, glutathione reductase and glutathione peroxidase were decreased by many nanomaterials. There are six factors that contribute to substantial oxidative stress in cultured hepatocytes (decreased GSH content, and reduced G6PDH, GRD, GPX, SOD and altered catalase activities). Cytotoxicity per se did not seem to fully explain the patterns of biological responses observed. With respect to structure-activity, nanomaterials of CeO2 were more effective than TiO2 in reducing glutathione reductase and SOD activities. The nanomaterials labeled D (TiO2 from Alfa Aesar, 22 nm dry primary particle size) and M (CeO2 from NanoAmor, 8 nm) were particularly biologically active compared to other nanomaterials of the same chemical composition. Nanomaterials with 99.9% chemical identity can be surprising different in their biological effects.

Linking ecosystem service supply to stakeholder concerns on both land and sea: An example from Guánica Bay watershed, Puerto Rico

Policies to protect coastal resources may lead to greater social, economic, and ecological returns when they consider potential co-benefits and trade-offs on land. In Guánica Bay watershed, Puerto Rico, a watershed management plan is being implemented to restore declining quality of coral reefs due to sediment and nutrient runoff. However, recent stakeholder workshops indicated uncertainty about benefits for the local community. A total of 19 metrics were identified to capture stakeholder concerns, including 15 terrestrial ecosystem services in the watershed and 4 metrics in the coastal zone. Ecosystem service production functions were applied to quantify and map ecosystem service supply in 1) the Guánica Bay watershed and 2) a highly engineered upper multi-watershed area connected to the lower watershed via a series of reservoirs and tunnels. These two watersheds were compared to other watersheds in Puerto Rico. Relative to other watersheds, the Upper Guánica watershed had high air pollutant removal rates, forest habitat area, biodiversity of charismatic and endangered species, but low farmland quality and low sediment retention. The Lower Guánica watershed had high rates of denitrification and high levels of marine-based recreational and fishing opportunities compared to other watersheds, but moderate to low air pollutant removal, soil carbon content, sediment and nutrient retention, and terrestrial biodiversity. Our results suggest that actions in the watershed to protect coral reefs may lead to improvements in other ecosystem services that stakeholders care about on land. Considering benefits from both coastal and terrestrial ecosystems in making coastal management decisions may ultimately lead to a greater return on investment and greater stakeholder acceptance, while still achieving conservation goals.

Developing a gene biomarker at the tipping point of adaptive and adverse responses in human bronchial epithelial cells

Determining mechanism-based biomarkers that distinguish adaptive and adverse cellular processes is critical to understanding the health effects of environmental exposures. Shifting from in vivo, low-throughput toxicity studies to high-throughput screening (HTS) paradigms and risk assessment based on in vitro and in silico testing requires utilizing toxicity pathway information to distinguish adverse outcomes from recoverable adaptive events. Little work has focused on oxidative stresses in human airway for the purposes of predicting adverse responses. We hypothesize that early gene expression-mediated molecular changes could be used to delineate adaptive and adverse responses to environmentally-based perturbations. Here, we examined cellular responses of the tracheobronchial airway to zinc (Zn) exposure, a model oxidant. Lung derived, BEAS-2B cells exposed to 2–10 µM Zn2+ elicited concentration- and time-dependent cytotoxicity. Normal, adaptive, and cytotoxic Zn2+ exposure conditions were determined with traditional apical endpoints, and differences in global gene expression around the tipping point of the responses were used to delineate underlying molecular mechanisms. Bioinformatic analyses of differentially expressed genes indicate early enrichment of stress signaling pathways, including those mediated by the transcription factors p53 and NRF2. After 4 h, 154 genes were differentially expressed (p<0.01) between the adaptive and cytotoxic Zn2+ concentrations. Nearly 40% of the biomarker genes were related to the p53 signaling pathway with 30 genes identified as likely direct targets using a database of p53 ChIP-seq studies. Despite similar p53 activation profiles, these data revealed widespread dampening of p53 and NRF2-related genes as early as 4 h after exposure at higher, unrecoverable Zn2+ exposures. Thus, in our model early increased activation of stress response pathways indicated a recoverable adaptive event. Overall, this study highlights the importance of characterizing molecular mechanisms around the tipping point of adverse responses to better inform HTS paradigms.

Role of complex organic arsenicals in food in aggregate exposure to arsenic

For much of the world’s population, food is the major source of exposure to arsenic. Exposure to this non-essential metalloid at relatively low levels has been linked to a wide range of adverse health effects. Thus, evaluating foods as sources of exposure to arsenic is important in assessing risk and developing strategies that protect public health. Although most emphasis has been placed on inorganic arsenic as human carcinogen and toxicant, an array of arsenic-containing species are found in plants and animals used as foods. Here, we evaluate the contribution of complex organic arsenicals (arsenosugars, arsenolipids, and trimethylarsonium compounds) that are found in foods and consider their origins, metabolism, and potential toxicity. Commonalities in the metabolism of arsenosugars and arsenolipids lead to production of dimethylated arsenicals which are known to exert many toxic effects. Evaluating foods as sources of exposure to these complex organic arsenicals and understanding the formation of reactive metabolites may be critical in assessing their contribution to aggregate exposure to arsenic.

Mercury Emissions Capture Efficiency with Activated Carbon Injection at a Russian Coal-Fired Thermal Power Plant

This EPA-led project, conducted in collaboration with UNEP, the Swedish Environmental Institute and various Russian Institutes, that demonstrates that the mercury emission control efficiencies of activated carbon injection technologies applied at a Russian power plant burning Russian coals are similar to those found at U.S. plants burning US coals. (The US funding was from funds provided to the EPA by the Department of State pursuant to the Bio-Chemical Redirect Program which engages former Russian (and other former Soviet) weapons scientists in research projects with US collaborators.)

GULF STREAM ( 16V894000 )

Dated: DEC 09, 2016 Gulf Stream Coach, Inc. (Gulf Stream) is recalling certain model year 2017 B Touring Cruiser motorhomes, model 5210, manufactured May 16, 2016 to July 15, 2016. The Certification label on the affecte…

RANGE ROVER ( 16V889000 )

Dated: DEC 09, 2016 Jaguar Land Rover North America, LLC (Land Rover) is recalling certain model year 2016-2017 Land Rover Discovery Sport vehicles manufactured May 30, 2016, to August 24, 2016, and 2016-2017 Range Rover…

LAND ROVER ( 16V889000 )

Dated: DEC 09, 2016 Jaguar Land Rover North America, LLC (Land Rover) is recalling certain model year 2016-2017 Land Rover Discovery Sport vehicles manufactured May 30, 2016, to August 24, 2016, and 2016-2017 Range Rover…

THOR ( 16V893000 )

Dated: DEC 09, 2016 Thor Motor Coach (TMC) is recalling certain model year 2016-2017 Outlaw motorhomes, models 37BG, 37LS, 37RB, 38RE and 38RF, manufactured January 13, 2016, to December 8, 2016. The affected vehicles h…