BEATRICE -- If you have plans this weekend to head to Rockford Lake, southeast of Beatrice in Gage County, or Swan Creek Lake No. 5, near Tobias in Saline County, stay out of the water. Officials say water samples showed high levels of a toxin released by blue-green algae, prompting health alerts for both lakes. The levels exceeded the state's threshold. Some types of toxic blue-green algae can produce dangerous toxins. You can still camp, fish and boat on lakes under an alert, but you should not have full-body contact with the water.