The city of Santa Monica will add chlorine to the Pico-Kenter storm drain during the last half of September to test whether bacteria in the drain water can be killed without harming ocean wildlife where the drain empties into the sea.
"The chlorine will take care of the bacteria, that is pretty certain," said Bob Ghirelli, executive officer for the state regional water quality control board in Los Angeles.
County Department of Health Services tests of water near the drain outlet on Santa Monica beach have occasionally disclosed high counts of coliform bacteria.
"The bacteria are caused by animal-waste runoff," Ghirelli said. "The city wants to assure the people on the beach that whatever bacteria are there will be taken care of."
He said the chlorination project will be monitored to see whether chlorine will evaporate in the drain after it kills the bacteria, and not flow out to sea and harm wildlife, he said.
If some of the chlorine flows into the ocean "it is possible that it could harm some fish," Ghirelli said. "But our biologists have determined that a controlled dosage of chlorine would not have any large-scale impact. There will be extensive monitoring during the chlorination to see what happens."
Carl Byker of Heal the Bay, an environmental group that is concerned about pollutants flowing from the drain into the ocean, called the chlorination experiment a good first step.
"But we are very concerned about any possible effect on marine life," Byker said. "And chlorination only deals with the bacteria problem."
Byker said he remains concerned about toxic wastes in the drain, including last week's three diesel fuel spills that polluted the beach and sea near the drain's outlet.
In a related development, city, state and county inspectors reported a near miss Wednesday in their efforts to catch people who dump toxic wastes into the storm drain.
According to Stan Scholl, Santa Monica general services director, inspectors discovered an oily substance in the gutter and storm drain near 26th Street and Pico Boulevard on Wednesday.
"We did not catch anyone in the act, but it looked like it was dumped there less than an hour before I drove by," Scholl said.
No one has been arrested in connection with Wednesday's discovery, Scholl and Ghirelli said.
Scholl said tests are being run on the oily substance.
"Dumping is a very difficult thing to . . . prove," Ghirelli said. "We almost have to see the dumping or trace it back up the gutter to a particular piece of property to make an arrest."
Ghirelli urged people who witness dumping to contact authorities.
Santa Monica is offering a $3,000 reward for information leading to the arrest and conviction of people who dumped diesel fuel into the storm drain last week, Mayor Christine E. Reed said.