Some of the same pollutants that apparently cause male fish in the Potomac and Shenandoah rivers to exhibit female characteristics may also leave them vulnerable to disease and large-scale fish kills, according to a new study. The study points to a possible link between the occurrence of intersex fish and fish kills in the rivers in recent years.

District police have identified the 11-year-old boy who is believed to have drowned after he fell in the Potomac River as Jorge Castro of Winchester.

The Maryland Department of the Environment says most of the potentially toxic coal ash sludge that spilled from a ruptured pipeline near Luke missed the Potomac River.