Tests of Wells Show High Nitrate Levels : Agua Dulce: Research team says it is too early to sound alarm on potential health hazards.


Nitrate levels do not meet public safety standards in about one fourth of 101 wells tested in Agua Dulce, according to preliminary tests by a team of UC Riverside scientists studying a longstanding and divisive issue in the hilly, rural community.

But the research team, meeting with townspeople last week, said it is far too early to say whether the concentrations of nitrates are high enough to create the potential for “blue baby syndrome,” an occasionally fatal illness in infants caused when the oxygen flow in the blood is impaired.

Nor can anyone yet say, the researchers added, whether the nitrates mostly occur naturally or if septic tanks are their main source and, if so, whether the community of 2,500 residents would have to build a sewer system that many fear could lead to runaway growth.


What is certain is that an ongoing 18-month study into the nitrate contamination in Agua Dulce, which means “fresh water” in Spanish, is reviving old disagreements in the unincorporated community about what problems these inorganic compounds pose, how to resolve them and if nitrates really do exist in large quantities.

In adults, nitrates can produce diarrhea. But if high concentrations of them are traced to septic tanks, it may be a sign that harmful viruses from sewage exist in drinking water, science team said.

State water quality officials initially found high concentrations of nitrates in the area a decade ago. Los Angeles County then conducted a series of studies, but many residents complained that nitrate levels were exaggerated and septic tanks were unfairly blamed.

The latest tests, begun this spring, were ordered by the state Regional Water Quality Control Board. Last Wednesday night, the UC Riverside researchers shared their initial results and promised a thorough investigation.

“We’re not going to leave any stone unturned,” Lanny Lund, a UC Riverside scientist, assured the crowd of about 80 persons at a meeting of the Agua Dulce Town Council.

The researchers also warned the crowd that they would like to test as many as 200 wells, but that many variables will influence their results.


For example, the average nitrate contamination found to date is only about 22.5 parts per million--or half the 45-p.p.m. level set as the state’s public health guideline. Of the 24 wells that did not meet the guideline, the highest reading was at least 170 p.p.m.

But the wells have not been declared off limits, and the research team explained that second readings are needed to confirm the data. In fact, some residents charged that their wells were not properly tested and the results were skewed.

What’s more, the researchers stressed, Agua Dulce’s mountainous, arid terrain could cause extreme variations in what they will learn by the fall of 1993 when their study concludes.

For instance, extremes of water tables--less than 100 feet below ground in some locations, as deep as 300 feet in others--determine the source of the contamination. Ground water closer to the surface may indeed be affected by septic tanks; water farther down may have a natural source of nitrates.

“We have no preconceived notions about what we will find,” said Zbigniew Kabala, UC Riverside professor of soil and environmental sciences, who heads the team. “No matter what we do, there will always be questions and answers.”

That pleased Linda Kirk, chairwoman of the Agua Dulce Water Committee, who doubted previous studies indicating potential problems in the area’s water. “This time,” she said, “they’ve promised us a fair and equitable study.”


Kirk and others in Agua Dulce doggedly cling to their bucolic lifestyle and single-family home sites no smaller than 2 1/2 acres. Many worry that a sewer system would spur unwanted development and impose hookup fees they cannot afford.

Some are reluctant to participate in the study, saying they fear confidentiality could be breached if their wells show high levels of nitrates, thereby lowering property values.

The testing is strictly voluntary, the UC Riverside team said, adding that they hope more residents participate so the goal of 200 wells can be reached.

The people of Agua Dulce have been through it all before, letting government agencies or private researchers test their water over the years--and the results have not always been to their liking.

“Now we’re all getting old together,” Joanne Swanson, an Agua Dulce Town Council member, said of the years of testing. She’s typical of many in this fiercely independent community who have not been easily swayed by earlier water tests showing potential hazards. “We’re not knee-jerk,” she said.

UC Riverside’s researchers said their study--officially called the Sierra Pelona Ground Water Study and financed by $250,000 in state and federal funds--will not only take water samples but do soil analyses to identify the source of nitrate contamination.


Besides septic tanks and natural sources, some believe the problem is caused by fertilizer and animal waste on chicken and pig farms that flourished in the area until the late 1950s.

Homeowner Tom Soper, who serves on study’s technical advisory committee, said after the meeting that the results could take on broader implications. “It’s the only study of its kind right now,” he said, “and it may affect land-use policy in other rural areas without sewers in the county.”