This video segment adapted from FRONTLINE: "Poisoned Waters" explains how the Potomac River, like many other rivers, serves as both a drinking water supply and a dumping ground for wastewater. With proper processing, a water recycling system works well. However, water treatment removes only known contaminants; there is a growing concern about "new contaminants," chemicals in the water that are still unregulated but could cause harm to humans and animals. [3:24]

Principles of Macroeconomics 2e covers the scope and sequence of most introductory economics courses. The text includes many current examples, which are handled in a politically equitable way. The outcome is a balanced approach to the theory and application of economics concepts. The second edition has been thoroughly revised to increase clarity, update data and current event impacts, and incorporate the feedback from many reviewers and adopters. Changes made in Principles of Macroeconomics 2e are described in the preface and the transition guide to help instructors transition to the second edition. The first edition of Principles of Macroeconomics by OpenStax is available in web view here.

By the end of this section, you will be able to:

Explain and analyze various arguments that are in support of restricting imports, including the infant industry argument, the anti-dumping argument, the environmental protection argument, the unsafe consumer products argument, and the national interest argument
Explain dumping and race to the bottom
Evaluate the significance of countries’ perceptions on the benefits of growing trade

By the end of this section, you will be able to:

Explain tarrifs as barriers to trade
Identify at least two benefits of reducing barriers to international trade