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Students Recognized at the Carolinas Regional Chapter of SETAC

We’re proud to share with you that two of our trainees received awards at the Carolinas SETAC (Society of Environmental Toxicology and Chemistry) in March.

Mariah Arnold, PhD candidate in Dr. Richard Di Giulio’s lab, won 3rd place in the Student Platform Presentation for her talk entitled “Selenium toxicity and bioaccumulation in fish associated with mountaintop removal coal mining effluent”. Her talk discussed her research in West Virginia involving the collection of native fish species to look at tissue compartment specific accumulation and speciation of selenium. She also mentioned a biofilm project in which biofilms placed in creeks and rivers in West Virginia are brought back to the lab and fed to fish in order to understand the trophic transfer of selenium and other contaminants of concern. Click below to read her abstract.

Abstract – Mariah Arnold

Mountaintop removal (MTR) coal mining activities in the Appalachian Coal Region (ACR) of the U.S. has significantly altered water chemistry in streams draining such operations. One of the major contaminants of concern is selenium (Se), a known avian and fish teratogen. Native fish were collected via electroshocking during 4 separate sampling events in April-July, 2011-2012. Collections took place at three sites; from a section of the Mud River, WV that drains the MTR-coal mining impacted main stem (MR7), sites on the un-impacted Left Fork of the Mud River (LFMR) as well as the newly impacted Big Ugly Creek (BU). LFMR and BU creek chub (Semotilus atromaculatus) fillets averaged similar concentrations of Se (2.01±0.3 and 1.68±0.5 mg/kg dw respectively) while MR7 creek chub fillets were significantly higher (6.20±1.4 mg Se/kg dw) (α=0.05 by Student’s t-test). Green sunfish (Lepomis cyanellus) fillets showed a similar pattern of higher Se concentrations in MR7 samples compared to BU and LFMR samples. Ovary and liver tissues from MR7 creek chubs also contained higher levels of Se (8.40-26.17 mg/kg dw) compared to the same tissues in creek chubs from LFMR (4.88-8.56 mg/kg dw). BU fish contained similarly low ovary and liver Se concentrations. Adult female fathead minnows (Pimephales promelas) fed on biofilms grown at sites in MR7 for two weeks contained qualitatively higher Se concentrations in liver and ovary tissues compared to fathead minnows fed on LFMR biofilms. Future experiments will increase limited sample sizes and will be combined with X-ray absorption near edge spectroscopy analysis to better understand how Se speciation changes can impact uptake and bioavailability in impacted aquatic systems.

Dan Brown, also a PhD candidate in the Di Giulio lab, won 1st place in the Student Poster Presentations for his poster entitled “Sublethal embryonic exposure to complex PAH mixtures alters later life behavior and swimming performance in Fundulus heteroclitus”. Click below to read Dan’s abstract.

Abstract – Dan Brown

Polycyclic aromatic hydrocarbons (PAHs) are important environmental contaminants in many aquatic systems. Acute embryonic exposure to PAHs is known to cause cardiac teratogenesis in fish, and research has shown that early life exposure to some types of hydrocarbons causes heart alterations and decreased swimming capacity in fish. A population of Atlantic killifish inhabits a Superfund site (Atlantic Wood Industries, Norfolk, VA—AW) that is heavily contaminated with a mixture of PAHs from former creosote operations. This population has developed resistance to the acute toxicity and teratogenic effects caused by the chemical mixture in sediment from the site. While studies have examined heart alterations and decreased swimming capacity in fish following exposure to PAHs, little is known about the impacts of more subtle, early life exposures, which are arguably more broadly applicable to environmental contamination scenarios. This study examined the later life consequences of early life exposure to sublethal concentrations of PAH mixtures in both the adapted and unadapted Atlantic killifish. Atlantic killifish from King’s Creek (non-polluted reference site) and the AW site were manually spawned and eggs were screened for development at 24 hours post fertilization (hpf). Screened eggs from both populations were then exposed to sublethal dilutions (0.1% and 1.0%) of Elizabeth River sediment extract (ERSE), from the AW site, as determined by dose response studies. Following exposure, embryos were screened for cardiac abnormalities at 144 hpf. Cardiac abnormalities were elevated in the King’s Creek 1.0% exposure, but were not present in the 0.1% exposure. Atlantic Wood fish had no observable cardiac deformities at both the 0.1% and 1.0% exposures. Ten embryos were randomly selected from all treatment groups and preserved for histology. The surviving embryos were returned to the incubator, hatched at day 14 pf, and reared in a flow-through system. Juvenile killifish were evaluated for startle habituation and diving/exploring behavior at 2 months post hatch (ph). King’s Creek killifish exposed to 1.0% ERSE were hyperactive in startle response testing relative to control killifish and demonstrated reduced exploring behavior in the dive test. Following behavioral testing, 5 juveniles were randomly sacrificed from each treatment group for histological assessment. The remaining juveniles were raised to 5 months ph and tested for critical swimming capacity (Ucrit), and dissolved oxygen consumption following 10-minute exercise bouts. P42-ES10356.

New Training Opportunities – Deadline extended to April 1st!

Interested in gaining some research experience with Duke’s Superfund Center? We have opportunities for you! Through our Research Experience for Undergraduates (REU) Program, you can apply to work with any of our 4 projects and 3 of our cores (Analytical Chemistry Core, Neural and Behavioral Toxicity Assessment Core, and Research Translation Core).

Contrary to the name of the program, you don’t need to be an undergraduate student. This opportunity is open to undergraduate and Master’s students.

Visit this page to learn more about the research opportunities available and how to apply. The deadline for applications is ~~March 15,~~ April 1st, 2013.

Spring Symposium – How Epigenomic Effects Mediate Persisting Actions of Developmental Toxicants

Friday, March 1

8:15am – 3:00 pm

*A light breakfast and lunch will be provided*

You are invited to join us for our spring symposium on the relationship between epigenomics and developmental toxicants. Epigenomics has been defined as “the study of the complete set of epigenetic modifications on the genetic material of a cell” (Wikipedia) and, thus, understanding how those genetic modifications interact with actions of toxic substances on development is critical.

The symposium is being held at the Doris Duke Garden Center at Duke University. To register for this free, public event by February 25th, please RSVP by email to eve.marion@duke.edu.

View the agenda here.

Hidden Dangers in Baby Products…

Many of the products we buy to protect our kids may be exposing them to risks…and it’s incredibly difficult to avoid

You may know that one of the research projects here at Duke deals with flame retardants, but do you know what they’ve been finding? The cover story for the Fall 2012 issue of Dukenvironment focuses on Dr. Heather Stapleton and her research on flame retardants. Read about the work her lab is doing to better understand the dangers of flame retardants in baby products, how flame retardants are (not) regulated, and how flame retardants may affect our health here.

Superfund Annual Meeting – 25th Anniversary of the Superfund Research Program

Dates: Sunday, October 21st through Wednesday, October 24th

The agenda, registration, abstract submission, and travel information can be found here.

July 25th, 2012 – Dr. Stapleton’s Testimony on Flame Retardants

On July 24th, Dr. Heather Stapleton provided expert testimony before the U.S. Senate Committee on the Environment and Public Works. Dr. Stapleton was part of a larger panel including Hannah Pingree, former Speaker of the Maine House of Representatives; Marshall Moore, Great Lakes Solutions, a Chemtura Business; William Rawson, Latham & Watkins LLP; and Tony Stefani, San Francisco Firefighters Cancer Prevention Foundation.

More information on the panel and an archived webcast can be found by clicking here.

You can also read Dr. Stapleton’s oral and written testimony.

Duke Students Receive Awards at NC Society of Toxicology Meeting

Congratulations to two of our PhD students, Max Leung and Xinyu (Candy) Yang, who both won awards at this year’s Spring NC SOT meeting. Max won the 1st place platform presentation award for his talk entitled “Later-life effects of mitochondrial DNA damage during development in the whole organism model Caenorhabditis elegans” and Candy won the 1st place poster presentation award for her poster entitled “Mechanism of silver nanoparticle toxicity is dependent on dissolved silver and surface coating in Caenorhabditis elegans.” The theme of the meeting was “TT21C: Network Biology and Toxicity Pathways.”

March 20th, 2012 – Slotkin Testimony Successful

Arysta LifeScience made the decision to halt the manufacture of MIDAS (methyl iodide) in the US. Methyl iodide is commonly used as a pesticide on strawberries. Dr. Ted Slotkin, one of our lead researchers, was involved in this process by providing expert testimony on the health effects of methyl iodide. Read more about the case, Arysta’s decision, and watch Dr. Slotkin’s testimony here.

May 17, 2011: CBS News – Hidden dangers in baby products?

Read the story here.

May 14, 2010: Dr. Slotkin SRP Research Brief: Childhood Exposures to Pesticides May Contribute to Obesity and Diabetes in Adults.

Read the research brief here.

September 17, 2008: Dr. Slotkin, EPA, and Chlorpyrifos

Dr. Ted Slotkin has submitted comments to a U.S. Environmental Protection Agency’s Scientific Advisory Panel regarding the Agency’s re-evaluation of the toxicity of the pesticide chlorpyrifos. Chlorpyrifos, a neurodevelopmental toxicant, remains one of the most widely used organophosphate pesticides, despite a long history of documented human and ecological risks from exposure through food, drinking water, and residential and occupational applications. Dr. Slotkin’s comments addressed recent epidemiological studies, mechanisms of toxicity, and routes of administration in animal studies. Read more here.