Environmental Medicine Update

by Marianne Marchese, ND

Environmental Global Health:

The Impact of Chemicals Abroad

Introduction

“Think globally, act locally” is a phrase coined several decades ago. It gave rise to awareness that the world is interconnected and disease can spread easily from one country to another. One country’s health problems affect those outside its borders. Acting locally is a call for people to become active participants, not only to improve health locally but also globally. Global changes can impact health locally as well. This concept is of utter importance in the area of environmental medicine and environmental health. One country chemical emissions affects other countries hundreds to thousands of miles away.

Environmental Impact

Chemicals are usually emitted locally but their impact can be felt globally creating both an ecological and human health risk. There is a global impact of chemicals released into the air. Soil, ground water, and drinking water can be contaminated affecting humans and animals and ecosystems.¹ Food imported into the US from other countries may be contaminated with pesticides that are no longer used in the US due to their adverse health effects. Countries exporting produce to the US are required to adhere to US pesticide tolerance limits, but testing of imported produce is in reality very limited. There is little information on the extent to which these imports may expose US consumers to elevated levels of pesticide residues, relative to domestically grown produce. A recent study looked at pesticide residue that could enter the US if exporters followed originating country requirements but not US pesticide tolerances.² It found that for the top 20 imported produce items, 120 439 kg of pesticides in excess of US tolerances could potentially be imported to the US, in cases where US regulations are more protective than those of originating countries. Based on low level dietary exposures, the selected pesticides in this study are associated with health effects on thirteen organ systems, and several are associated with cancer.²

High-dose exposure to pesticides, such as occupational exposure, has the most harmful effects on humans. Most poisonings and deaths from acute pesticide exposure occur in developing countries, not the US. This is due to many factors, including: developing countries have a higher proportion of the population involved in agriculture, they have poorer pesticide handling practices, they commonly use unsafe equipment (such as leaky backpack sprayers), and they generally employ more toxic pesticides than those used in developed countries.³ They are using highly toxic pesticides that have been banned in US but may be reentering the US through imported produce.

Traveling to other countries for work or vacation may also be a source of exposure to harmful chemicals not used in the US. Air pollution in some countries is significantly higher than in the US. There may not be any regulation of chemicals found in water or used food manufacturing and preparation. Another risk to travelers is the fact that some countries spray them with disinfecting chemicals while on the plane. Many countries have required aircraft disinfection since the early 1930s, treating the landing aircraft with insecticides to minimize the spread of potential disease. The most common product used contains a 2% synthetic pyrethroid insecticide. Pyrethroid can affect the nervous and immune systems, and is suspected to be an endocrine-disrupting chemical.⁴ The World Health Organization (WHO) and most countries and airlines have deemed pyrethroid safe for aircraft disinfection with passengers either on or off the plane. In September 2001, USA Today published an article detailing the use of insecticides on aircraft while traveling to other countries. Six countries required spraying while passengers were still onboard: Grenada, India, Kiribati, Madagascar, Uruguay, and Trinidad and Tobago.⁵ The flight attendant was not even allowed to exit the plane, thus creating an occupational hazard for those who work flights overseas. A recent study investigated the urinary pyrethroid metabolite levels of flight attendants working on US domestic and international commercial aircrafts to assess whether those on disinfected flights have elevated pyrethroid body burden compared with those on planes not treated with pesticides and the US general population. It was concluded that working on commercial aircrafts disinfected by pyrethroids resulted in elevated body burden of 3-PBA, cis– and trans-Cl2CA, two urinary metabolites of pyrethroids.⁴

Pesticides and insecticides are not the only chemicals used locally that are having global effects.

Air pollution is a major threat to every country, as it can negatively affect human health and wildlife ecosystems. WHO estimates more than 2 million people die every year from inhaling tiny particles present in indoor and outdoor air pollution. Dr. Maria Neira, WHO director for Public Health and Environment, has stated, “Across the world, city air is often thick with exhaust fumes, factory smoke or soot from coal burning power plants. In many countries there are no air quality regulations and, where they do exist, national standards and their enforcement vary markedly.” Air pollution can travel from one country to another. Several studies have determined that the air quality over parts of North America is being affected by the pollutants transported from Asia.^6,7 A recent study showed that the trans-Atlantic transport of North African dust by summertime trade winds increases ambient particulate matter (PM) concentrations in Texas above air quality standards.⁸ Due to loosened restrictions on coal plants in Mexico, the airborne pollutants from coal-burning power plants along the US–Mexico border affects air quality and health in the US.⁹ It is clear that one country’s chemical emissions, environmental policies, education, and awareness have global effects.

Solutions

The world’s entire atmosphere is connected, bringing pollutants across borders. Identifying and implementing global solutions is not an easy task, given differing cultures, awareness and education, governments, environmental controls and regulations, and economics.

“Local actions, national policies, and international agreements are all needed to curb pollution and reduce its widespread health effects,” said Dr. Michal Krzyzanowski, head of the WHO European Centre for Environment and Health in Bonn, Germany. The US Environmental Protection Agency (EPA) runs a collaborative program with Mexico called Border 2012, to improve the environment and protect the health of the nearly 12 million people living along the border. The binational program focuses on cleaning the air, providing safe drinking water, reducing the risk of exposure to hazardous waste, and ensuring emergency preparedness along the US–Mexico border. Many other countries are working on curbing emissions as well. Even China, known for air pollution and poor environmental regulations, has taken steps in the right direction. In February 2012, China’s Ministry of Environmental Protection (MEP) issued two major new regulations: a revision to the ambient air quality standards to include PM2.5, and a new definition of China’s Air Quality Index. By the end of the year, China had completed and began operating a network of real-time PM2.5 monitors in 74 cities through the country.

Think globally, act locally, sometimes needs to be turned around. Educating people in developing countries on simple steps to decrease environmental pollutants is often a task left up to a small group of concerned individuals. One such group is Naturopaths Without Borders (NWB; www.naturopathswithoutborders.org), a group of physicians and medical students whose mission is to provide naturopathic health care to impoverished communities while empowering those communities through education, supporting growth, and cultivating sustainable resources. In Cap-Haïtien, Haiti, the group is working on environmental concerns as well. One area of education is trying to curb the use of use of hazardous chemicals (hydrochloric acid) for drain cleaner and bleach. There is no safe method of disposal of such toxic chemical cleaners in Haiti. The bottles typically get burned as trash, contributing to poor air quality and health issues. In Haiti, NWB is spreading the word about trying not to drink out of plastic bottles, which end up being burned as trash. It is educating people not to burn plastics and Styrofoam – a difficult task, since there is no alternative method of disposal. There is limited city garbage collection and disposal. These grassroots efforts will hopefully make way for larger governmental regulations.

Summary

It is clear that in this age of technology, the world is interconnected through the Internet. Most people do not consider that the world is also connected through a shared environment, which may affect health locally and globally. Environmental global health includes regulations, policies, research, education, and training directed at health problems related to environmental exposure. The goal of improving health for all people, by reducing global environmental exposures that lead to avoidable disease, needs to be a priority of all humankind.

Notes

1. Huijbregts MA et al. Geographical scenario uncertainty in generic fate and exposure factors of toxic pollutants for life-cycle impact assessment. Chemosphere. 2003;51(6):501–518.

2. Neff RA et al. A comparative study of allowable pesticide residue levels on produce in the United States. Global Health. 2012;8.2 Published online 2012 January 31.doi:10.1186/1744-8603-8-2.

3. Pesticide Health Risks. World Resources Institute. Accessed online Sept 24 2013. http://www.wri.org/publication/content/8437.

4. Wei B, Mohan KR, Weisel CP. Exposure of flight attendants to pyrethroid insecticides on commercial flights: urinary metabolite levels and implications. Int J Hyg Environ Health. 2012;215(4):465–473.

5. Woodyard C. Fumes over planes treated with pesticides. USA Today. 2001;9. Accessed online Sept. 24, 2013. http://usatoday30.usatoday.com/travel/business/2001/2001-09-10-pesticides.htm.

6. Wuebbles DJ, Lei H, Lin J. Intercontinental transport of aerosols and photochemical oxidants from Asia and its consequences. Environ Pollut. 2007 Nov;150(1):65–84.

7. Carmichael GR, et al. Asian aerosols: current and year 2030 distributions and implications to human health and regional climate change. Environ Sci Technol. 2009;1;43(15):5811–5817.

8. Bozlaker A et al. Quantifying the contribution of long-range Saharan dust transport on particulate matter concentrations in Houston, Texas, using detailed elemental analysis. Environ Sci Technol. 2013;47(18):10179–10187.

9. Blackman A et al. Health impact of power-exporting plants in northern Mexico. Energy Policy. 2012;44(C):34–45.

Dr. Marchese is the author of 8 Weeks to Women’s Wellness: The Detoxification Plan for Breast Cancer, Endometriosis, Infertility, and other Women’s Health Conditions. Dr. Marchese graduated from the National College of Naturopathic Medicine. She maintains a private practice in Phoenix, Arizona, and teaches gynecology at Southwest College of Naturopathic Medicine. She was named in Phoenix Magazine‘s 2010 Top Doctor Issue as one of the top naturopathic physicians in Phoenix. Dr. Marchese is a contributing author for the Townsend Letter and lectures on topics related to women’s health and environmental medicine throughout the US and Canada. She is past vice president of the Arizona Naturopathic Medical Association and current member of the board of directors for the Council on Naturopathic Medical Education.