One of the confounding issues an environmental scientist faces is communicating the concept of size and scope to their audience. If a small amount of pollution is mixed with clean water, the pollution is perceived by the general public as somehow becoming less toxic. In some cases, it is. A drop of ethanol in water will not cause as much damage to the human body as pure ethanol. However, the actual amount of pollution is still in that water. As you learned in the Module 6 Critical Thinking assignment, chemicals exist that can accumulate in an organism each time they come into contact with it.

What if the example chemical ethanol could not be digested or eliminated from the human body? As a person drinks from a glass of water containing a drop of ethanol, that ethanol would stay in the body. Each subsequent drink of water would build up another drop of ethanol. Eventually, those drops of ethanol would add up, poisoning the person as much as if drinking a glass of pure ethanol.

Think of Earth’s hydrologic systems as a human body. Much of our excess stormwater and wastewater that fails to be processed by waste treatment facilities end up in our rivers, streams, and coastal regions. If contaminants within that wastewater do not decompose quickly, and are also easily absorbed by plants and animals who live in that water, the toxic potency of those contaminants will build up over time, possibly causing a plethora of health problems throughout the ocean food web.

Watch the 2-hour video, FRONTLINE:  Poisoned Waters (PBS). Post a minimum of a 250-word summary and personal review, and make any connections with the readings. As you review the video, consider how industrial and agricultural chemicals in the ocean food web parallel the path the DDTs take through the land food web as you learned about in Module 6’s critical thinking activity. Think about what the sources of the pollution were, if more than one polluter involved, and what is meant by “legacy polluters”. Review the essays of other students, post a minimum of two thoughtful comments of approximately a paragraph (a single sentence is not a comment), and reply to any and all comments posted about your own review.