Introduction

Chemical safety is a major priority of EPA and its researchers. Moving toward a safer and more sustainable environment requires producing new and existing chemicals in safer ways and that are nontoxic. It means having the information and methods needed to make better informed, more timely decisions about chemicals. The challenges are formidable:  tens of thousands of chemicals currently are in use and hundreds more are introduced every year. Many of these chemicals have not been evaluated thoroughly for potential risks to human health and the environment. Also, the consequences of use over a chemical’s life cycle (from production to disposal) are not thoroughly evaluated. EPA’s research on chemical safety is geared to meet this challenge.

Using innovative approaches, EPA scientists and their partners are embracing the principles of green chemistry (PDF) (2 pp, 71K, About PDF)—the design of chemical products and processes that reduce or eliminate the use or generation of hazardous substances—to produce safer chemicals. They also are integrating a diversity of scientific disciplines to develop new prediction techniques, pioneering the use of innovative technologies for chemical toxicity testing, and designing tools to advance the management of chemical risks.

Chemical Safety for Sustainability includes research in computational toxicology, nanotechnology, endocrine disrupting chemicals, human health, and pesticides (PDF) (103 pp, 943K, About PDF).

This section highlights some of the many accomplishments that EPA scientists and researchers made in 2010 to advance chemical safety for sustainability, including:  key support to the federal response to the tragic oil spill in the Gulf of Mexico, major accomplishments in the management of chemical risk, achievements from EPA’s high-tech Computational Toxicology Research Program, bringing top scientists together to advance the science of perfluoroalkyl acids (PDF) (53 pp, 1MB, About PDF), the release of two case studies exploring the broad environmental and human health impacts of nanomaterials (PDF) (2 pp, 215K, About PDF), advances in endocrine disruptors research, the understanding of dioxin toxicity, and more.

Crisis Science: All Hands on Deck

EPA scientists provide key support to the federal response to the Deepwater Horison oil spill.

On April 20, 2010 the mobile offshore drilling unit Deepwater Horizon, located some 40 miles off the coast of Louisiana exploded into flames. Eleven crewmembers were killed, 17 were injured, and what would prove to be the worst oil spill in history had begun.

Overnight, EPA staff scientists and engineers became highly sought-after experts to inform and help formulate the oil spill-related activities of the National Response Team, an organization comprised of 16 federal departments and agencies tasked with responding to oil and hazardous substance pollution events. EPA provided full support to the U.S. Coast Guard, which served as the National Incident Commander for the federal response, leading and coordinating emergency and containment activities.

The first priority following the release of oil into the Gulf of Mexico was protecting public health. EPA scientists mobilized to monitor air quality and assess environmental conditions for potential air and water contamination. To provide Gulf Coast residents with the latest information, Agency scientists frequently collected and updated environmental data and posted it on the EPA Web site.

In addition to setting up emergency environmental monitoring operations, EPA researchers developed sampling approaches and Quality Assurance Plans to support data collection and ensure the transfer of reliable information for assessing environmental exposures and effects of the oil spill. Their work provided the Agency with support to identify and evaluate likely exposure pathways through which released and dispersed oil, as well as oil dispersant, could reach people and “ecological receptors” such as plankton, fish, wildlife, and coastal vegetation.  

EPA experts provided science to support Coast Guard decisions on clean up and mitigation activities. A critical priority was to provide information on oil dispersants.

EPA-led studies provided the first comprehensive, standardized toxicology tests, including evaluations of potential endocrine-disrupting activity, on oil dispersants available for use in response to the Deepwater Horizon oil spill.

The tests were conducted to ensure that decisions about dispersant use in the Gulf of Mexico were grounded on the best available science. EPA began its own scientific analysis of eight dispersant products on the National Contingency Plan Product Schedule, a list of dispersants and other mitigating substances and devices that may be used to remove or control oil discharges.

The overall goal of actions taken in response to the unprecedented release of oil into the Gulf of Mexico was to minimize the known threat the released oil posed to the environment. Spill management strategies, practices, and technologies that were implemented include the use of sorbents, floating booms, and skimming operations to mechanically remove oil from the water; burning the oil in place; and applying dispersants.

Based on their ongoing work to support immediate and near-term remediation efforts, EPA researchers have begun designing sampling and analysis plans that can support long-term assessments of the incident, as well as the efficacy of the remediation and the recovery of the area.

Computational Toxicology Research

EPA scientists pioneer the use of high-tech computer technologies to advance the science of toxicology.

Tens of thousands of chemicals currently are in commerce, and hundreds more are introduced every year. With so many chemicals, the pace and cost of traditional, animal-based toxicity tests have meant that only a small fraction of chemicals have been adequately assessed for potential risk.

EPA’s Computational Toxicology Research Program (CompTox) is working to change that. Together with their partners, CompTox researchers are working to revolutionize how chemicals are assessed for potential toxicity to humans and the environment. The CompTox Research Program conducts innovative research that integrates advances in molecular biology, chemistry, and computer science to more effectively and efficiently rank chemicals based on potential risks.

CompTox accomplishments during 2010 included:

• EPA Screened 1,000 Chemicals Using ToxCast™
  EPA’s ToxCast™ program was launched in 2007 to develop a cost-effective approach for prioritizing the thousands of chemicals that need toxicity testing. ToxCast™ uses advanced science tools to help understand how human body processes are impacted by exposure to chemicals and to determine which exposures are most likely to lead to adverse health effects. ToxCast™ started screening 1,000 chemicals from a broad range of sources including drugs donated from pharmaceutical companies, “green” chemicals and chemicals in cosmetics and other consumer products. 

• International Partnership for Enhancing Chemical Safety Established
  EPA and the European Chemicals Agency (ECHA) forged a partnership in 2010 that will promote enhanced technical cooperation on chemical management activities.
  EPA will provide regulatory data (excluding confidential business information) and research from ToxCast™ to ECHA, and in return, ECHA will share the approaches and chemical data being used under the Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH) law that was enacted by the European Union in June 2007.

• EPA and Partners Collaborated to Improve Chemical Screening
  EPA, the National Institute of Environmental Health Sciences National Toxicology Program (NTP), and the National Institute of Health Chemical Genomics Center (NCGC) welcomed the U.S. Food and Drug Administration (FDA) to the Tox21 collaboration. Tox21 merges federal agency resources (research, funding and testing tools) to develop ways to more effectively predict how chemicals will affect human health and the environment. The collaboration was established in 2008 to develop models that will be able to better predict how chemicals will affect humans.

• EPA Opened Access to Chemical Information
  EPA released the online Toxicity Reference Database (ToxRefDB), a tool that allows scientists and others to search and download thousands of toxicity testing results on hundreds of chemicals. The database includes 30 years and some $2 billion worth of testing results that were previously found primarily as paper documents.

 

Embracing Change: The Next Generation of Risk Assessment

EPA developed new risk assessment practices to match the pace of scientific innovations.

In 1953, James Watson and Francis Crick presented the structure of the DNA helix in a scientific paper. Just 57 years later, scientists are predicting genetic diseases and developing treatment for previously incurable ailments.

There is no doubt that our basic understanding of disease and its causes is changing at an astonishing speed. New findings in microbiology and genetics are announced on an almost daily basis, and while this is excellent news in terms of human and environmental health, it also is important to ensure a framework is in place to interpret these groundbreaking discoveries.

EPA is aware of this need and is leading a collaborative effort among several federal and state agencies to advance the science of risk assessment through greater incorporation of new knowledge in molecular biology. EPA’s Next Generation Risk Assessment (NexGen) was launched in 2010.

New NexGen tools will evaluate toxicity at a molecular level and are intended to support both traditional risk assessment and green chemistry approaches.

The NexGen project is a part of the larger EPA national research effort to develop Chemical Safety for Sustainability (CSS), the science and methods needed to produce safer chemicals using principles of green chemistry. CSS aims to increase our knowledge about the potential health effects of chemicals currently manufactured and to develop improved sustainable management strategies to deal with chemicals that pose risks to humans and wildlife.

EPA held a NexGen workshop in November 2010, at its research campus in Research Triangle Park, North Carolina, to elicit input from experts on several early-stage health effects assessments, or prototypes. Expert comments were used to refine the prototypes and help identify key points for a subsequent workshop held in February 2011.

The Agency is developing a better idea of how to proceed in the future and how to best adapt modern risk assessment to the ever-evolving science that is behind it.

 

Nanomaterial Case Studies

EPA researchers are leading the effort to study the broad implications of nanotechnology.

EPA is leading scientific efforts to understand the potential risks to humans (PDF) (2 pp, 216K, About PDF), wildlife, and ecosystems (PDF) (2 pp, 212K, About PDF) from exposure to nanomaterials—those having at least one dimension between 1 and 100 nanometers (nm). They often have novel or unique properties that can arise from their small size.

Through innovation and discovery, EPA scientists and their partners are studying the unique properties of nanomaterials, determining their potential impacts, and developing approaches to evaluate any risks. They also are exploring how nanomaterials can be used effectively to clean up contaminants released into the environment (PDF) (2 pp, 215K, About PDF).

In 2010, EPA released two case studies to be used as part of a larger process to identify what is known and, more importantly, what is not yet known that could be of value in assessing the broad implications of certain nanomaterials.

Nanomaterial case studies EPA released in 2010 include:

• Nanomaterial Case Studies:  Nanoscale Titanium Dioxide in Water Treatment and in Topical Sunscreen (Final), released in November 2010, considers two specific applications of nanoscale titanium dioxide (nano-TiO₂):  (1) as an agent for removing arsenic from drinking water, and (2) as an active ingredient in topical sunscreen.
  The intent of these case studies is to characterize the current state of knowledge on the environmental impacts of nano-TiO₂ as used in these two specific applications, as well as areas where information is missing. Note that some information gaps are specific to nano-TiO₂ either as a drinking water treatment agent or as an ingredient in topical sunscreen. Other gaps may pertain more broadly to nano-TiO₂ irrespective of its application, and still other gaps may pertain even more widely to nanomaterials in general. In this way, the case studies are expected to be used in developing research strategies that will support comprehensive environmental assessments of nanomaterials.

• In August 2010, EPA released the External Review Draft of the Nanomaterial Case Study:  Nanoscale Silver in Disinfectant Spray. This case study does not represent a completed or even a preliminary assessment of nano-silver (nano-Ag); rather, it uses a comprehensive environmental assessment that starts with the product life cycle but encompasses fate and transport processes in various environmental media, exposure-dose characterization, and ecological and health effects as well as other direct and indirect ramifications of both primary and secondary substances or stressors associated with a nanoscale silver.

Each chapter in the external draft report includes lists of questions that reflect information gaps in that portion of the document. Some of these knowledge gaps or research needs are specific to the use of nano-Ag in disinfectant spray; others may relate more broadly to nano-Ag irrespective of its application, while still others may apply more widely to nanomaterials in general. Readers are encouraged to consider the questions listed throughout the document and offer specific comments on how individual questions or research needs might be better expressed.

Providing Answers to Chemical Safety Concerns

EPA brought top scientists together to share information about perfluoroalkyl acids.

EPA brought together leading researchers studying perfluoroalkyl acids (PFAAs) (PDF) (53 pp, 1MB, About PDF)—a class of chemicals the Agency has identified as potential threats to human health and the environment—at the 3rd Biennial PFAA Days Workshop, held June 8-10, 2010, at the Agency’s research facilities in Research Triangle Park, North Carolina. The workshop provided an opportunity to share recent findings and to explore potential partnerships.

PFAAs and their derivatives are used in hundreds of consumer applications, including fabric and carpet coatings (offering stain resistance), lubricants, fire-fighting foam, denture cleaners, and personal products such as shampoo.

In 2009, EPA issued provisional health advisories for two of the chemicals—PFOA and perfluorooctane sulfonate (PFOS)—in drinking water and developed action plans to address several other chemicals, including the long-chain PFAAs of new concern.

EPA has one of the largest groups of scientists in the world studying PFAAs, providing expertise in many disciplines. More than 60 articles in peer-reviewed publications have been produced by EPA researchers over the past 4 years to improve the understanding of the health and environmental impacts of these chemicals.

EPA research highlights at the workshop included determining where PFAAs go in the environment after they are released. EPA researchers have developed analytical methods that enable scientists and water quality managers to determine if PFAAs are in the environment and at what concentration.

EPA scientists are testing consumer products in 12 categories (PDF) (40 pp, 1.3MB, About PDF) to evaluate whether companies are reducing PFOA content in their products under the program. Preliminary observations show a significant reduction of PFOAs in mill-treated stain-resistant carpeting and some carpet treatment products. Other product categories are showing mixed trends. An interim report will be published in late 2011.

EPA researchers are identifying biological activity on how PFAAs cause reproductive and developmental effects in rodents. Application of biologic methods is needed to understand potential toxic effects. Researchers are examining how PFAAs may interact with nuclear receptors, specific proteins that can alter genetic code and are important to the normal development of an embryo/fetus and maintenance of homeostasis (the body’s ability to regulate biological processes) in adults.

In addition, EPA researchers are exploring whether PFAA exposure plays a role in the incidence of obesity and metabolic syndrome. The chemicals are being studied because of their potential ability to influence energy metabolism (how biological fuels such as fat and sugar are being stored or converted into energy).

EPA Endocrine Disrupter Research

EPA scientists investigate chemicals that may interfere with the endocrine system to advance risk assessment and support efforts to protect human health and the environment.

EPA’s endocrine disruptor research program was established to address the many industrial chemicals and pesticides that may interfere with the normal functioning of human and wildlife endocrine systems. Environmental chemicals that disrupt the endocrine system have the ability to cause a variety of problems with development, behavior, and reproduction (PDF) (120 pp, 319K, About PDF).

EPA research addresses exposures to pesticides, toxic chemicals, and environmental mixtures of chemicals that interfere with the function of the endocrine system. Major accomplishments in during 2010 include:

• Development of a Short-Term Screening Method for Thyroid Toxicants
  EPA endocrine studies on thyroid toxicants provided scientific support to the Agency’s updated policy that incorporates faster, less costly screening studies into decision making. The findings provided support to waiving the requirement for developmental neurotoxicity studies for chemicals with known thyrotoxic properties.
• Development of a New Approach for Testing Environmental Chemicals for Thyroid Hormone Disruption
  EPA scientists developed a new approach for testing environmental chemicals for thyroid hormone disruption using thyroid gland explant cultures from tadpoles of the African clawed frog (Xenopus laevis), an aquatic species commonly used in research.
• A New Approach for Identifying Chemicals That Disrupt Male Reproductive Development (PDF) (8 pp, 262K, About PDF)
  EPA scientists developed a new approach, using a short-term in vivo screening assay,for identifying phthalate esters (chemicals commonly used to make plastics flexible) that disrupt male reproductive development. The assay measures alterations in fetal rat testis endocrine function and gene expression levels after five days of treatment. It is able to predict the adverse effects of the chemicals in long-term, multigenerational studies. The new approach reduces the use of animals, shortens the timeframe for hazard identification, and provides data that are useful for quantitative risk assessments for this class of toxicants.
• Toxicity Testing of Oil Dispersants after BP Spill
  Following the BP spill in the Gulf of Mexico, EPA scientists tested the acute toxicity and endocrine disrupting activity of eight potential oil dispersants. Tests were conducted using sensitive aquatic organisms found in the Gulf such as mysid shrimp (Mysidopsis bahia). Results confirmed that the dispersant used for cleanup, Corexit 9500a, was no more or less toxic that the available alternatives. Some of the dispersants tested contained endocrine-active contaminants; however, results showed that none of the eight dispersants displayed significant endocrine-disrupting activity via the androgen or estrogen signaling pathway. (For more information on EPA research to support emergency response efforts in the Gulf of Mexico, see Crisis Science: All Hands on Deck, on page 34 of this report.)