The Potomac is one of the most prominent rivers in the United States, a defining ecological feature of Washington, D.C., at the same time it reveals the city’s history of racial inequality and disenfranchisement. Writer, historian, educator and herbalist Charlotte Taylor Fryar recounts that tale in her ambitious “Potomac Fever,” reviewed in the latest BookShelf by contributing editor Jennifer Weeks, herself a Washington native.

With many states dominated by a few powerful industries — whether oil, mining or agriculture — the influence of campaign dollars can have an outsize effect on legislation, even to the point of corruption, notes the latest Reporter’s Toolbox. So while the U.S. Congress may be languishing, environmental journalists can dig up stories on lobbying at the state level using a powerful data source.

Industry experts and government regulators have long known that radionuclides reside in oil and natural gas. Yet radioactive emissions and waste continue to threaten the lives of workers and community members across the country. Investigative journalist Justin Nobel on the opportunities and urgent need for reporters to drill into a story steeped in questions of accountability, health and justice.