Warnings about eating fish have extended into the Neuse River from its tributaries because state officials are concerned about contamination with industrial chemicals.

People should limit consumption of catfish and carp from Walnut Creek and Rocky Branch and from the Neuse River just below Crabtree Creek, eating no more than one meal per month of catches from the waterways because the fish may contain high levels of PCBs, the advisory said.

The contamination was detected as a follow-up to an investigation of environmental contamination from Ward Transformer, which was found to be widespread.

But health officials cannot say specifically where this contamination came from because of the distance downstream and length of time PCBs can remain in the environment.

Dr. Ricky Langley, a physician with the state Division of Public Health, said PCB levels were elevated, but not high enough to advise against eating fish.

People should limit consumption of other species of fish from Rocky Branch and Walnut Creek to one meal per week. The stretch of the Neuse under advisory is from just below Crabtree Creek to Auburn-Knightdale Road.

Langley said long-term exposure to elevated levels of PCBs may increase risk of cancers and weaken the immune system. The contaminant is also linked to neurological problems in children.

Ward Transformer built and reconditioned transformers near Raleigh-Durham International Airport from 1964 through 2005. The company's methods of handling PCB-laced oil drained from the transformers led to widespread contamination of the site and nearby creeks. Fish consumption advisories have already been posted on Lake Crabtree, Brier Creek upstream of Lake Crabtree and Crabtree Creek upstream and downstream of the lake to the Neuse.