En Español

Regulatory officials called Mission Creek a “toxic hot spot” in 1999,  and marked it as one of the bay’s most-polluted spots. But today, no one can say how the little waterway measures up, even as sewage is periodically dumped into it.

That’s because the water isn’t regularly tested and hasn’t been in years, according to Kenya Briggs, a spokesperson for the Public Utility Commission.

The San Francisco Department of Public Health, the San Francisco Public Utilities Commission, and the San Francisco Bay Regional Water Quality Control Board were unable to give Mission Loc@l any water quality information about the creek more recent than 2007.

Mission Creek occupies a three-quarter-mile stretch from AT&T Park to Seventh Street. New public parks and housing  along the creek are attracting a host of visitors, including boaters and water-loving dogs. A handful of  residents also live in houseboats parked on the creek year-round.

Despite the uptick in traffic, and the fact that the PUC occassionally uses the creek to dispose of sewer overflow, the utility is waiting for the results of a two-year recreation study before deciding whether it will test the water, according to Briggs.

“As you know, we now have a kayak launch ramp in the Creek, but we can’t seem to get the PUC to acknowledge that kayaking involves water contact,” houseboat resident Corinne Woods wrote in an email to Mission Loc@l.

In San Francisco, sanitary sewage and street runoff are mixed – called a combined sewer – and fully treated together before being discharged into the bay. It’s the only Bay Area city to go to such lengths to treat its runoff.

Storm debris floating in Mission Creek Tuesday.

Storm debris floating in Mission Creek Tuesday.

However, if water volume is unusually high after heavy rains like the city has experienced this week, some of the excess is discharged after it goes through only a basic filtration to take out most of the sediment and floatable debris. Bacteria and chemical contamination remain.

Roughly 6 percent of this “combined sewer overflow” into waterways is sanitary sewage from buildings; most is storm water, said Briggs.

The city’s permit from the water board to discharge the overflow says that the city may only do so during heavy rains, and it “shall take all reasonable steps to minimize or prevent any discharge or sludge use or disposal in violation of this Order that has a reasonable likelihood of adversely affecting human health or the environment.”

Mission Creek has seven combined sewer discharge points, which were installed in the late 1980s.

The utility does test some San Francisco beaches for bacteria because of its combined sewer overflow, which occurs at several points citywide in addition to Mission Creek. However, the nearest water quality test sites are miles away from the creek, near Candlestick in the south and at Aquatic Park in Fisherman’s Wharf to the north.

As for chemical contaminants, Briggs said that the most recent city monitoring of the creek happened in the 1980s, and PUC staff have no recollection of where that data was kept.

Yet, the creek was considered a “regional toxic hot spot” in 1999 by the San Francisco Bay Regional Water Quality Control Board.

That report put Mission Creek in the bottom ten percent of roughly 100 locations sampled in the San Francisco Bay, according to Wil Bruhns, who directs the toxic limits program for the regional water board. Staff found silver, chromium, mercury, lead, zinc, PCBs and other contaminants.

Furthermore, in 2007 the board listed Mission Creek as an impaired waterway due to the presence of several serious contaminants, including lead, PCBs, ammonia, and polycyclic aromatic hydrocarbons. It’s unclear which data was used to make this determination, and staff at the water board were unable to track down definitively when the most recent tests were conducted on the creek.

The water board considers the contaminants in impaired waterways one by one, looking at a single pollutant over all the waterways at once, and probably won’t be addressing any of the contaminants in Mission Creek this year.

According to a draft document on the water board’s website, the city and the water board corresponded over Mission Creek in 1998; the document refers to a “letter requiring San Francisco to define the extent of the sediment contamination, and determine if the [combined sewer overflows] are continuing to cause the contamination or acting to resuspend contaminated sediments already there.”

The upshot is that the city and the board may have previously determined that the combined sewer overflow did or didn’t contribute to the chemical contamination in the creek. Because Mission Creek is in an industrial area, it’s plausible that runoff does add to chemical pollution, but no one at the PUC or the water board was able to remember the correspondence or give Mission Loc@l the letters or the report referring to them.

In the interim while it conducts the study on recreation, the PUC has set up an email list to warn when combined sewer overflow has happened, but the utility won’t test the water until after October 2011 when the recreation study is complete. The study randomly measures when “specifically to see if people are in contact with the water,” said Briggs.

Houseboat residents suspect toxics remain trapped in the sediment at the bottom of the creek, but many feel the water itself is safe except after the combined sewer overflows. Ginny Stearns, a member of Mission Creek Conservancy, said that a hardy species of sea squirt, Ciona intestinalis, is wiped out after the overflows, but she said it’s unclear why that is or what long-term damage occurs, since the sea squirt does manage to reappear by the summer.

Then again, residents also speak of a time when a nearby paint company would dump its cleanup into the creek, and the entire waterway would turn green or blue with paint. It’s a lot better now, they said.

Houseboat resident Sarah Davis pointed to the abundance of plants and wildlife as evidence that the water can’t be all that bad. Some houseboat residents self-report that they even swim in it, on occasion. Davis said she’s lived on the creek her whole life, and it’s the nicest it’s ever been.

Meanwhile, the PUC is updating the nearby pump station, which should help to reduce the much-bemoaned odor caused by storing whatever’s filtered out of the overflow. These upgrades should be complete sometime mid-year, Briggs said.