A KSAT 12 Defenders test of the water in the San Antonio River in three different locations revealed much higher bacteria levels in the river as it flows out of the San Antonio Zoo.
The water quality in the river has been under discussion since some highly publicized remarks made by Dallas Mavericks owner Mark Cuban in 2007.
He trashed the River Walk, the state's top tourist attraction, calling it an "ugly, muddy-watered thing."
Some San Antonians were offended by the remarks, but many took note and started taking measures to clean up the river.
The Defenders took samples of water in the river on Aug. 8, a 100-degree-plus day during a dry period when runoff would not be an issue.
Tests were done on water flowing into the zoo, out of the zoo and at the River Walk. The level of E. coli in the water was measured at a lab certified by the state and was used to determine whether other more harmful microbes are present.
E. coli in the water coming out of the zoo was found to be much higher than it was going in.
- Above the zoo, the E. coli level was 272.
- Coming out of the zoo: 12,600.
- At the River Walk: 1,550.
Visitors to the zoo were stunned at the increase in the level of E. coli in the water coming out of the zoo.
"That is surprising,” said zoo visitor Michael Rodriguez. “I hope it would be kept out of our drinking water."
Jon and Carolyn Rocha were visiting from Fort Worth and are Mavericks fans. They said they believe the tests gave some vindication to Mark Cuban.
The city recognized the problem years ago and began making plans to treat the water coming out of the zoo.
A water treatment plant is now under construction that will use ultraviolet light to kill bacteria in the water as it leaves the zoo.
April Alcoser, Public Works Department spokeswoman, said it should be completed soon.
“The whole purpose of the UV water treatment facility is to disinfect some of the discharge that is coming from the San Antonio Zoo's main outfall,” Alcoser said.
She said 99 percent of the bacteria will be killed and that will mean a cleaner River Walk -- and a quieter Mark Cuban.
"We're expecting that once the treatment facility is in operation, it's going to significantly lower the bacteria levels," Alcoser said.
The bacteria in the water leaving the zoo are caused by the feces of the hundreds and thousands of residents of the zoo and visiting animals such as birds.
The treatment plant should be operational by January.
The Defenders plan to re-test the water to see how well it works.