It might take many years to reduce all of South County groundwater’s perchlorate levels to the acceptable standard, but the water is vastly cleaner and safer than it was less than 10 years ago due to ongoing cleanup efforts, according to regulators.
The Perchlorate Community Advisory Group held its first meeting in about six months Thursday at the San Martin Lions Club. Community members listened as water regulators showed the last remaining “hotspot” of potentially dangerously high perchlorate concentrations in the groundwater continues to shrink.
The citizens’ board also announced their commitment to continue monitoring the safety of local drinking water – despite the diminishing perchlorate threat – by shifting their focus to keep an eye on other potentially harmful chemicals such as nitrates in the groundwater.
“We have not stopped where we are now,” said PCAG chair and longtime San Martin resident Bob Cerruti, who last week was elected by his peers as the new chair of the group.
“We want to continue monitoring, and we want to see what we can do to continue to make sure the water is as clean and safe as we can for our residents,” Cerruti added.
In 2003, authorities discovered a massive plume of perchlorate in the groundwater basin emanating from a road flares factory owned and operated by Olin Corporation on Tennant Avenue, to areas throughout south Morgan Hill and San Martin.
Authorities believe the perchlorate leached into the groundwater from Olin’s facility for more than 40 years, starting in the 1960s when the factory opened.
Perchlorate occurs naturally, but it can be harmful to humans – especially children and pregnant women – if consumed in higher-than-background quantities.
Olin has been held accountable for the contamination and forced by environmental regulators to clean the chemical out of the groundwater. The corporation was also required to provide bottled “replacement water” to residents with highly contaminated wells.
Dean Thomas, engineering geologist for the Central Coast Regional Water Quality Control Board, gave a presentation Thursday that showed the levels of perchlorate in the South County groundwater basin are steadily on the decline.
In 2004, as many as 188 households hooked up to residential wells in south Morgan Hill and San Martin areas were receiving bottled water, according to Thomas’ report. Today, the number of wells showing potentially harmful perchlorate levels, as established by state and federal regulators, has declined to six.
Of those, three are still using bottled water, and three are using an “ion exchange system” to remove the chemicals from the groundwater, Thomas said.
Olin continues to maintain its own large-scale ion exchange system to clean a large contaminated “hotspot” in the groundwater basin, underground in the area between Fisher and Middle avenues in south Morgan Hill. A pipeline nearly a mile long extracts the contaminated water from the aquifer near Maple Avenue and sends the liquid to the cleanup facility located at the former Olin site.
That system removes the harmful chemicals, and returns the cleaner water back underground, according to authorities.
Thomas told residents at Thursday’s meeting that households can remove perchlorate from their well water through reverse osmosis.
The last meeting of the PCAG before Thursday was in February, and board members said the declining pace of the meetings corresponds to the steady, yet slowing progress. Cerruti noted that while in the first few years of cleanup after the perchlorate was discovered, the decontamination rate was rapid.
But lately, even though progress continues, it has slowed down significantly due to the declining presence of perchlorate in the water, Cerruti said. Also, complicating the effort is the presence of an aquitard – or underground layer of bedrock that exhibits low permeability – in the area of the remaining hotspot.
The cleanup effort has been so successful that even Morgan Hill City staff will recommend removing a 1 percent perchlorate surcharge on City customers’ water bills some time next year, according to City Manager Steve Rymer. The surcharge has been added to water bills since 2003 in order to offset the City’s cost of cleaning perchlorate from City wells. It has fluctuated over the years, reaching 15 percent in 2006, according to Rymer.
In 2004, some thought the cleanup effort could take up to 50 years, and Thomas noted that ion exchange systems can take “decades” to completely clean a groundwater area.
But PCAG members remain excited about the pace. PCAG member Swanee Edwards, who represents the City of Morgan Hill on the board, said regulators have removed about 147 pounds of perchlorate since 2004.
“I would say it’s an unequivocal success, and a beautiful example of grassroots organizing,” said Edwards, who noted the citizens group has stayed intact and devoted to holding Olin accountable without funding and without litigation.
She added that the perchlorate effort and the PCAG’s mission will likely be part of the legacy of longtime San Martin resident Sylvia Hamilton, a founder of PCAG who died in February. Hamilton presided as chair of the last PCAG meeting just a few days before her death and played a major role in “holding Olin’s feet to the fire,” as Cerruti previously commented.
“What (Hamilton) did here was a one-of-a-kind situation,” Edwards said. “She was mad about the spill, she was concerned about her fellow San Martinians but, being unincorporated, what could they do? They couldn’t sue, and the County didn’t seem at the time to take a large interest in what was happening. This stands out as one of her best accomplishments.”
PCAG’s next meeting will take place at an undetermined date in June.
In the future, board members want to use the momentum they’ve established on the perchlorate problem to monitor other potentially harmful elements in local drinking water, such as nitrates and other organic material.
Nitrates are not at a dangerously high level yet in South County, but they could get there if left unchecked, PCAG members said. The main causes of nitrates in drinking water are fertilizer runoff from agricultural operations, leaking septic systems and erosion of natural deposits.
“Nitrates were the No. 1 organic element that needed to be cleaned up in this area before perchlorate came on the horizon,” Cerruti said.
What is perchlorate?
Perchlorate is a naturally occurring and manmade contaminant increasingly found in groundwater, surface water and soil. Most perchlorate manufactured in the U.S. is used as an ingredient in solid fuel for rockets and missiles. In addition, perchlorate-based chemicals are also used in the construction of highway safety flares, fireworks, pyrotechnics, explosives, common batteries, and automobile restraint systems.
Contamination hazards
Perchlorate contamination has been reported in at least 20 states. Perchlorate greatly impacts human health by interfering with iodide uptake into the thyroid gland. In adults, the thyroid gland helps regulate the metabolism by releasing hormones, while in children, the thyroid helps in proper development. Perchlorate is becoming a serious threat to human health and water resources.
Source: The California Department of Toxic Substances Control
