EHP : The Researcher's Perspective

As many as 70,000 volunteers and rescue workers responded to the 11 September 2001 World Trade Center (WTC) attacks, many toiling for months to clear mountains of debris containing a range of toxic compounds. Health effects seen since that time in WTC responders include respiratory, gastrointestinal, chemosensory, and mental health problems; many of these effects have persisted for years. In this podcast, Philip Landrigan discusses his work with WTC responders as a physician and an epidemiologist and how lessons learned from the WTC cleanup may be applied to other disasters. Landrigan is the chair of the Department of Preventive Medicine and dean for Global Health at Mount Sinai School of Medicine in New York.

Although dispersants have been used to help clean up oil spills since the 1960s, it wasn't until the Deepwater Horizon disaster in the Gulf of Mexico that these chemicals made their way into the public consciousness. Use of dispersants always involves an environmental tradeoff, but the Deepwater Horizon situation presents special considerations because the chemicals are being used a mile underwater for the first time ever. In this podcast, Dana Wetzel discusses the dispersants used in the Deepwater Horizon spill and research needs regarding how these chemicals may affect aquatic species. Wetzel is a senior scientist and program manager at the Mote Marine Laboratory in Sarasota, Florida.

Exposure to certain chemicals or stressors in utero can cause immediate health effects for fetuses and babies including lowered birth weight, birth defects, and impaired neurodevelopment. New lines of research are now showing that prenatal exposures may also contribute to health problems that typically arise later in life—such as obesity, diabetes, cardiovascular disease, cancer, and Parkinson disease—via changes to DNA transcription and the hypothalamic–pituitary–adrenal axis. In this podcast, Deborah Cory-Slechta discusses the phenomenon known as the fetal basis of adult disease. Cory-Slechta is a professor of environmental medicine at the University of Rochester School of Medicine and Dentistry.

In the United States more than 40,000 women die of breast cancer each year, and almost 200,000 women develop the disease. Although survival rates have improved and risk factors have been identified, the causes of breast cancer remain unclear. In 2004 researchers at the National Institute of Environmental Health Sciences (NIEHS) began recruiting sisters of breast cancer patients for a study to explore environmental and genetic factors behind this disease. Now that more than 50,000 women have been recruited, Dale Sandler discusses what comes next for the Sister Study. Sandler is the principal investigator of the Sister Study and chief of the Epidemiology Branch at the NIEHS.

Flame retardants known as polybrominated diphenyl ethers (PBDEs) are added to products such as furniture, car seats, textiles, and electronics. These chemicals improve safety by giving consumers more time to react if a fire breaks out. But now they are also showing up in the food we eat, the dust in our houses, and the bodies of possibly the entire U.S. population; meanwhile, recent evidence suggests the potential for worrisome neurodevelopmental effects. In this podcast, Heather Stapleton discusses what we know about routes of PBDE exposure and how these exposures may affect human health. Stapleton is an assistant professor of environmental chemistry at the Nicholas School of the Environment at Duke University and coauthor of "Metabolism of polybrominated diphenyl ethers (PBDEs) by human hepatocytes in vitro"

In the 1950s biologists began noticing unusual behavior and various reproductive health problems in wild animals. Environmental health analyst Theo Colborn was one of the first to start asking what those trends might mean for humans. In this podcast marking the 40th anniversary of Earth Day, Colborn discusses her research on the endocrine-disrupting effects of chemicals in the Great Lakes ecosystem-research that broke new ground in the field of environmental toxicology. Colborn, co-author of Our Stolen Future, now heads The Endocrine Disruption Exchange in Paonia, Colorado, and is a professor emeritus at the University of Florida in Gainesville.

Every year about 2,000 new chemicals are submitted to the U.S. Environmental Protection Agency (EPA) for safety approval. Figuring out how a chemical might affect human health involves lab studies that can cost millions of dollars and take years to complete. Now a team of researchers at the EPA is working on a way to make the safety testing process more efficient and less expensive. In this podcast, Robert Kavlock describes the EPA ToxCast™ project, which uses existing toxicity knowledge as a blueprint for broad-scale chemical assessment. Kavlock is director of the EPA National Center for Computational Toxicology and coauthor of "In vitro screening of environmental chemicals for targeted testing prioritization: the ToxCast project"

An estimated 1-1.5 million Americans live with autism, a neural disorder characterized by impaired social interaction and communication. Some research suggests environmental factors play a role in autism, while other findings point to a genetic basis. More recently there's been a heated public debate about whether autism is caused by the mercury in vaccines commonly given to children. In this podcast, Irva Hertz-Picciotto discusses the implications of research comparing blood mercury levels of autistic children with those of typically developing children. Hertz-Picciotto is an environmental epidemiologist with the Medical Investigation of Neurodevelopmental Disorders (MIND) Institute at the University of California, Davis, and the first author of "Blood mercury concentrations in CHARGE Study children with and without autism" [EHP 118:161-166 (2010)]

DDT is unique among the "dirty dozen" compounds banned under the Stockholm Convention on Persistent Organic Pollutants because specific exceptions are made for the indoor spraying of DDT to control the mosquitoes that spread malaria. DDT is a cheap, effective weapon against the spread of this disease, which infects nearly 250 million people each year and kills nearly 1 million. However, little is known about the long-term human health effects of exposure to DDT in the context of indoor spraying. In this podcast, Brenda Eskenazi describes research issues surrounding the use of DDT to control disease vectors. Eskenazi is a member of the DDT Expert Group of the Stockholm Convention, and is the Maxwell Professor of Maternal and Child Health and Epidemiology and director of the Center for Children's Environmental Health Research at the University of California, Berkeley. She also is the first author of "The Pine River Statement: human health consequences of DDT use" [EHP 117:1359-1367 (2009)]

Industrial-scale farms known as concentrated animal feeding operations (CAFOs) have become an increasing focal point for environmental health research because of their emissions and concerns they may contribute to antibiotic resistance, adverse community impacts, and zoonotic disease outbreaks. They are also a source of political controversy in states including North Carolina and Missouri where government agencies are grappling with decisions about CAFO monitoring and permitting. In this podcast, Peter Thorne describes some of the health concerns surrounding these facilities. Thorne, director of the NIEHS-funded Environmental Health Sciences Research Center at the University of Iowa, is the lead author of an EHP mini-monograph on environmental health effects of CAFOs [EHP 115:296–320 (2007)].

A number of recent studies have reported finding measurable levels of persistent organic pollutants in human milk, and many daily activities expose nursing women to toxic chemicals that can end up in their milk. Although many of these chemicals can cause adverse health effects in humans, studies consistently conclude that, overall, the benefits of breastfeeding outweigh the potential toxicity threats posed to nursing children. In this podcast, Lynn R. Goldman discusses why breastfeeding is still the optimal method of infant feeding despite the presence of pollutants in human milk, and describes precautions that mothers can take to protect their milk. Goldman is a principal investigator for the Johns Hopkins University Center for the National Children's Study and a coauthor of "Global screening of human cord blood proteomes for biomarkers of toxic exposure and effect" [EHP 117:832-838 (2009)].

Heat waves kill more people in the United States each year than any other natural hazard, and many regions worldwide are experiencing more frequent and more severe heat waves. But not all people and not all places have the same vulnerability to heat-related health effects. Identifying those who are more vulnerable will be critical to effective public health interventions. In this podcast, Colleen Reid discusses an innovative method for mapping the sections of urban areas across the United States where residents are more likely to suffer heat-related health effects. Reid is the lead author of "Mapping community determinants of heat vulnerability" [EHP 117:1730-1736 (2009)] and a PhD candidate at the University of California, Berkeley.

The many adverse health effects caused by chronic arsenic exposure are a concern for the hundreds of millions of people worldwide whose drinking water contains elevated levels of this naturally occurring element. A new rodent study suggests arsenic may also contribute to immune suppression. In this podcast, Josh Hamilton describes the potential implications of this finding for human health, including the possibility that arsenic exposure could help explain why certain populations have been hit harder by pandemic novel H1N1 flu. Hamilton is the senior author of "Low-dose arsenic compromises the immune response to influenza A infection in vivo" [doi:10.1289/ehp.0900911] and a senior scientist at the Bay Paul Center for Comparative Molecular Biology and Evolution, part of the Marine Biological Laboratory in Woods Hole, Massachusetts.

Although childhood leukemia is the most common childhood cancer, little is known about its causes. Incidence of acute lymphocytic leukemia, the most common childhood leukemia, is highest in industrialized countries and rose significantly between 1975 and 2004, suggesting environmental agents may play some role. In this podcast, Mary H. Ward explores the idea that polychlorinated biphenyls (PCBs) could be one such agent. Ward is the lead author of "Residential exposure to polychlorinated biphenyls and organochlorine pesticides and risk of childhood leukemia" [EHP 117:1007-1013 (2009)] and a senior investigator in the Division of Cancer Epidemiology and Genetics at the National Cancer Institute in Bethesda, Maryland.

The global population is undergoing sweeping changes that are shifting the balance toward an older and more urbanized population that experiences more chronic disease and a greater gap between rich and poor. In this podcast, Kenneth Olden tells what these changes mean in terms of public health challenges and how he believes we must prepare to meet these challenges. Olden was director of the NIEHS and the National Toxicology Program from 1991 to 2005. He served as NIEHS director emeritus and continued his research activities at the institute until 2008, when he left to help establish a new school of public health at the Hunter College campus of the City University of New York.