LAS VEGAS (AP) - Southern Nevada's top water official is raising concerns about "measurable quantities" of uranium showing up in the Colorado River, the region's primary source for drinking water.

Southern Nevada Water Authority chief Pat Mulroy blames uranium mining, particularly near Moab, Utah.

In a letter Monday to federal Interior Secretary Dirk Kempthorne, Mulroy urges the department to "carefully evaluate" the effect on water quality before authorizing new mining claims near the river.

She says federal law includes strict limits on uranium in drinking water, and says it's expensive and difficult for cities to get it out.

A report this week found southern Nevada tap water continues to meet or exceed all standards set by the federal Safe Drinking Water Act.