(AP) In Puget Sound, pollution is forever. That's the message scientists hope residents of Western Washington will remember the next time they flush chemicals down their toilets or curbside drains.

Because the sound is shallow at the northern end like a bathtub, ocean water does not easily come in to flush out pollutants, state scientists told about 400 people at a one-day scientific conference on toxins in the sound. The gathering was organized by People for Puget Sound.

Because of the sound's geography, polychlorinated biphenyls or PCBs are still being found in Chinook salmon caught in its waters, at levels up to six times higher than fish from the Columbia and Sacramento rivers and along the east side of Vancouver Island. PCBs have been banned since the 1970s.

"Once it's here, it stays in the sound," said Sandra O'Neill, a fish contamination expert with the state Department of Fish and Wildlife.

That's just one example of the way Puget Sound is polluted by what consumers flush down drain pipes. Scientists are also finding fish dosed with antidepressants and shellfish tainted with amnesia-causing toxins, researchers said at the Wednesday forum.

"People need to be mad as hell about this situation, but they aren't," said Brad Ack, head of the Puget Sound Action Team, a government agency. "We haven't gotten the message across."

Ack suggested the possibility of requiring consumer warning labels; banning some or all substances like flame retardants that don't break down; and updating sewage treatment plants to trap contaminants like caffeine and prescription drugs.

PCBs, for example, have been cycling through the ecosystem for decades, getting picked up by worms and other mud-dwelling invertebrates, which are eaten by fish that are consumed by larger fish, mammals and birds. The animals die, then decompose and the cycle repeats.

The same thing happens with flame retardants that O'Neill found in herring, lingcod, rockfish and English sole. Researchers reported that chemical flame retardants _ which are still added to electronics, seat cushions and fabrics _ can cause developmental and hormone problems in fish.

Many of the sound's pollutants are ingested by people intentionally, including antidepressants, drugs to curb nicotine addiction, caffeine and hormones. The chemicals then flow to the sea in sewer water. Research shows that some of these chemicals can skew the ratio of female to male fish, or reduce the fertility of male fish.

The situation is troubling, said Edward Furlong of the U.S. Geological Survey in Denver, because exposure for the fish is "constant, direct and unavoidable."