The latest episode in the American Chemical Society's (ACS') award-winning Global Challenges/Chemistry Solutions podcast series describes research concluding that the number of people without access to flush toilets or other adequate sanitation is almost double the previous estimate.

Based on a report by Jamie Bartram, Ph.D., and colleagues in ACS' journal Environmental Science & Technology, the new podcast is available without charge at iTunes and from http://www.acs.org/globalchallenges.

It may be the 21st century, with all its technological marvels, but 6 out of every 10 people on Earth still do not have access to flush toilets or other adequate sanitation - measures that protect the user and the surrounding community from harmful health effects - according to a new study.

Jamie Bartram and colleagues explain that the current definition of "improved sanitation" focuses on separating humans from human excrement. However, it does not include treating that sewage or other measures to prevent it from contaminating rivers, lakes and oceans. Using that definition, 2010 United Nations estimates concluded that 4.3 billion people had access to improved sanitation and 2.6 billion did not.

The new estimates used what the authors regarded as a more realistic definition from the standpoint of global health, since untreated sewage is a major cause of disease. They refined the definition of "improved sanitation" by discounting sewage systems lacking access to sewage treatment. They concluded that about 60 percent of the world's population does not have access to improved sanitation, up from the previous estimate of 38 percent.