Section 3.17 mentions that arsenic poisons human cells because it halts the production of ATP. This happens because the structure of arsenic atoms closely resembles that of phosphorus atoms—so close, in fact, that arsenic can take the place of phosphorus in chemical reactions. Why would the substitution of arsenic atoms for phosphorus atoms prevent the formation of ATP?

Transcribed Image Text:

FOCUS ON OUR ENVIRONMENT 3.17 A Way with Arsenic The element arsenic is a powerful poison. When arsenic atoms enter cells, they disrupt the Krebs cycle and electron transport chain. ATP production stops cold, and the affected cell then dies. This effect has made arsenic a useful ingredient (in carefully regulated amounts) in some anticancer drugs, wood preservatives, and insecticides. On the other hand, murderers have used killer doses of arsenic to dispatch their victims for thousands of years. More often, people are exposed to low doses of arsenic in tainted food, water, or industrial emissions. Arsenic occurs naturally in soil and rock in many areas of the world, including parts of the western United States and in Bangladesh, where some 19 million people drink arsenic- laced well water. With enough exposure, arsenic can cause cancer, disfiguring skin disorders, and severe damage to many internal organs. Dr. Abul Hussam, a chemist at George Mason University in Virginia, was born in Bangladesh. When he learned that his own family's well was contaminated with naturally occurring arsenic, he and his brothers built a device that costs about $35 and that can filter the arsenic from roughly 130 gallons of water per day-enough to meet the needs of several families (Figure 3.29). In 2008 the National Academy of Engineering awarded Dr. Hussam a $1 million prize for his work. He pledged $250,000 to help fund more arsenic research. Nearly all the remaining prize money will go to buy filters for poor Bangladeshi families. Because arsenic is a problem in the United States as well, the Environmental Protection Agency recently announced it will sponsor research on improved technologies for limiting arsenic pollution of water and soil. MEWNAL FILTER WO FILTER Figure 3.29 Dr. Abul Hussam's low-cost water filtering device effectively removes arsenic from drinking water. George Mason University