State water quality expert Dr. David Ting will explain the
recent state-established public health goal (PHG) for perchlorate
in drinking water to the City Council and the public Wednesday
night.
State water quality expert Dr. David Ting will explain the recent state-established public health goal (PHG) for perchlorate in drinking water to the City Council and the public Wednesday night.
Ting, the senior toxicologist for the California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment (OEHHA), is the primary author of the state report that set 6 parts per billion as the PHG.
Council will also be asked to approve leasing a perchlorate treatment plant for the Nordstrom well, getting ahead of an expected water shortage during hot weather and the well’s history of occasionally testing above 4 ppb.
The public health goal was announced in March by OEHHA and is 2 parts per billion above the 4 ppb previously used as an “action level.”
A PHG is based upon scientific research and public health considerations, disregarding whether the level is technically or economically possible to achieve under normal circumstances. The PHG must be set first and is the basis on which drinking water standards will be set by the Department of Health Services. Those standards will include technical and economic considerations.
Six ppb is 2 ppb higher than the level currently used by the state as an “action level,” the point at which water providers must notify their customers of the chemical’s presence. It is not the level at which they must stop serving the water – 50 ppb – though the City of Morgan Hill shuts down its wells when they test higher than 4.0 ppb. The State of California was waiting for the PHG to be set before establishing drinking water standards.
Ting first explained his findings at a meeting of the Central Coast Regional Water Quality Control Board in March. Olin Corp., is the company whose safety flare manufacturing plant on Tennant Avenue in Morgan Hill was responsible for perchlorate invading the South Valley underground aquifer.
The chemical, over the 40 years the plant was in operation, caused a plume of perchlorate stretching from Tennant Avenue south through the eastern part of San Martin and reaching some wells in north Gilroy.
Perchlorate is also found in private and municipal wells north and east of the Tennant site, causing the City of Morgan Hill to lease a perchlorate treatment plant for its Nordstrom well, ensuring sufficient water supplies during the hot summer months. The plant operated from June 1 through Oct. 31. Olin has, so far, refused to take responsibility for the pollution north of Tennant, saying the aquifer flows south and southeast.
On April 14 the council approved leasing a perchlorate treatment plant from U.S. Filter for $158,082 beginning May 1 and extending through September. The March hot spell increased water use by 25 percent, said Jim Ashcraft, public works director told the council.
The cost could be higher if the amount of water treated is higher than predicted. U.S. Filter will charge $231 per acre foot.
The Regional Board, however, has asked for studies on the northeast flow, admitting that there could be reasons why Olin’s perchlorate ended up at East Dunne and Murphy, site of the Nordstrom well.
While the city has asked Olin to pay these perchlorate removal costs and has a reasonable expectation that it will in the end, at the moment, the city is paying the costs itself. In order to cover the in creased costs, the city has added a perchlorate surcharge to water bills. Council said that, when Olin reimburses the city for the costs, water users will receive a rebate.
Ashcraft said the city will continue to test its well water down to 4 ppb, regardless of the state’s PHG.
“We’ll test down to the detection limit approved by DHS (Department of Health Services), which is 4 ppb,” Ashcraft said.
• On the council’s consent calendar (items approved without public discussion unless requested) is a request to authorize dedicating the new police facility at 16200 Vineyard Blvd. in the name of former Chief of Police John R. Moreno.
