The world’s most pervasive groundwater pollution problem – nitrate in drinking water – is under scrutiny in the richest farming region of the United States.
This week, a report for the California Legislature revealed that 250,000 people living in Central California, including four of the top five agricultural counties in the U.S., are currently at risk for nitrate contamination in their drinking water. Many of them are among the poorest Californians.
Nitrate, in this instance, is a byproduct of nitrogen fertilizer. In drinking water, high concentrations of it can interfere with the oxygen-carrying capacity of infants younger than six months, and, if left untreated, may lead to death from “blue baby” syndrome. Some studies suggest that long-term consumption of nitrate in drinking water may increase the risk of Parkinson’s disease, Alzheimer’s disease, and cancer, including non-Hodgkin’s lymphoma.
Europe began tackling the problem in 1991 by designating “vulnerable zones” where the groundwater and streams were polluted with nitrate. Those zones now encompass 40 percent of the landmass in the continent. Today, 27 countries test for nitrate at 31,000 monitoring stations on or near farmland; and, with some overlap, at 27,000 monitoring stations in lakes, streams, and the ocean. Since 1991, reports show, nitrate use has dropped off sharply in Europe.
In the U.S., the United States Geological Survey estimates that as many as 7 percent of private wells and 3 percent of public wells may be contaminated with nitrate, with the highest concentrations found around irrigated farms.
In Central California, according to the state report, cropland is the source of more than 90 percent of the nitrate that winds up in underground basins. Contamination can take a long time: some of the nitrate in well water today comes from fertilizer that was applied a century ago. The report, prepared by the University of California, Davis, recommends charging farmers higher fees for fertilizer and using the money raised to help rural communities pay for expensive water treatment systems.
Taking a more stringent approach, in a first for the U.S., a regional water board on California’s Central Coast voted unanimously on March 15 to require 3,000 vegetable and berry farmers to test their private wells for nitrate. If the farmers wish, they can form coalitions of like operations and choose one well for testing among them, but they must report the results to the board.
“It’s historic,” said Jeff Young, chairman of the Central Coast board. “It’s going to increase the requirements on irrigated farming. There’s going to be more accountability as to the use of fertilizers and pesticides. The problems took decades to create, but the time has come now to begin to clean up these important public resources, the groundwater and the streams.”
The California Farm Bureau is expected to appeal the decision to the State Water Resources Control Board, which oversees the regional agencies.
Most of the nation’s lettuce, broccoli, and strawberries come from the agricultural valleys of the Central Coast. Vegetable and berry farms from Monterey to Santa Barbara, an area that includes the Salinas Valley, the nation’s Salad Bowl, bring in $7 billion in gross revenues per year. A board report states that farmers in this area have been over-fertilizing their irrigated crops — by nearly 40 percent for the past decade alone — sending 75,000 tons of nitrate into local rivers and groundwater basins every year. Studies show that 120 public wells and probably thousands of private wells are contaminated with unsafe levels of nitrate because of the farmers’ wasteful ways.
The Central Coast Regional Water Quality Control Board, which has the authority to regulate polluters, will review the test results for the private wells; and farmers with 500 acres or more will face an approximate deadline of 2015 to stop over-fertilizing. The rules also tighten pesticide use on the largest farms.
“It’s our most important order of the past generation,” said Roger Briggs, the board’s executive director. “Usually, when we have some regulatory action, there’s one significant problem like a gas station cleanup or a few wells that are threatened. But in this case, we’ve got all these different facets – riparian and aquatic habitats with toxicity, destruction of vegetation along creeks, and thousands of wells that are not just threatened but are actually degraded. It’s big.”
California water officials first brought the nitrate problem to the attention of the Legislature in 1988. Today, Central Valley dairy farmers are required to test their wells for nitrate (the nitrate there mostly leaching from manure), but the rule does not apply to farmers with irrigated fields. Beginning in 2004, Central Coast farmers were given five years to voluntarily monitor their fertilizer use, but the underground water quality did not improve, according to board reports.
“There’s a fear I think amongst growers that if they do throttle back on fertilizer, their yield will suffer,” said Briggs. “They may see that as a bit of a gamble. It’s a strong cultural norm, and it’s not easy to sway or change that norm.”
The new Central Coast rules require farmers with 500 acres or more of irrigated cropland to test their wells for nitrate once a year; smaller farmers would have to test them only once. The idea is that the farmers would pump and fertilize, effectively treating the groundwater by letting the crops take up the nitrate in it. It’s a cleanup effort that will require many decades.
For their part, over three years of hearings, the farmers told the board they objected to being portrayed as evil polluters and held accountable for nitrates that have been in the groundwater for a long time. They favored shifting the responsibility for groundwater monitoring to farm coalitions run by consulting firms. These firms would have gathered data from public, not private wells.
Norm Groot, executive director of the Monterey County Farm Bureau and a director of Farmers for Water Quality, said the rules ignore the impacts of septic systems, urban runoff, and old military bases in the region. With modern techniques, he said, farmers have dramatically reduced the amount of fertilizer they use.
“There is no science to say that a farmer is a direct contributor to the water directly below him,” Groot said. “We accept some of the responsibility, but we are not willing to take full responsibility. To skewer ag completely for that really isn’t fair.”
At the same time, a coalition of environmentalist groups, including the Environmental Defense Center, Sierra Club, and Monterey Coastkeeper, favored an earlier board proposal that would have required all farmers, regardless of the size of their operations, to test their wells annually and stop over-fertilizing within six years.
“I no longer have confidence that we will be targeting the right people,” said Steve Shimek, the Coastkeeper executive director, noting that even small farms can be big polluters. “The trajectory of this process has been to make the rules weaker and weaker. Agriculture has tremendous political power, and it has been getting away with polluting California’s water for decades.”