Atrazine, one of the most widely used broadleaf herbicides in the United States, began showing up in Hawai`i water in 1983. It had been used by the sugar industry since 1961 and accounted for up to 50 percent of total herbicide usage in cane fields, according to the Hawaiian Sugar Planters’ Association.
According to a letter November 14, 1983, from Don J. Heinz, director of the HSPA’s experiment station in `Aiea to the director of the state Department of Health, HSPA had recently learned that atrazine had been found in the ground water in areas where it was in use on the continental United States. In response to that, Heinz said, HSPA began tests on water around several O`ahu sites. Attached to Heinz’s letter were results of the testing, which showed levels ranging from 50 to 170 parts per trillion in water at Kunia and Waipahu and at 60 ppt at an O`ahu Sugar Company pump in `Ewa. (The Environmental Protection Agency has established a maximum concentration level of 3 parts per billion for atrazine.)
Also attached to Heinz’s letter was a two-page “Memorandum: Toxicology of Atrazine” that compared the toxicity of atrazine to that of table salt, or sodium chloride, which also was present in the water samples. “It is recognized that the human physiological system does have specially adapted mechanisms to handle NaCl whereas atrazine is obviously not a necessary component in human nutrition,” the memorandum stated. “However, the comparison contributes to the proper significance to attach to this finding. Acutely, salt is more toxic than atrazine even though salt is necessary for proper health.”
Over the next several years, the state and HSPA continued to monitor atrazine in drinking water statewide. Atrazine usage appears to have peaked in 1986, when 388,732 pounds were sold in the state. The following year, 43 water sources (out of 117 tested) had been found to be contaminated with atrazine. Affected wells were on Kaua`i, O`ahu, Maui, and Hawai`i.
With the phase-out of sugar, the use of atrazine in Hawai`i has plummeted. By 1993, atrazine sales in the state had fallen to 259,000; by 1995, Hawai`i sales of the chemical totaled 19,650 pounds. It still is used in macadamia orchards and in other diversified agricultural operations.
Despite the reduced use, atrazine continues to turn up regularly in well water and, in at least one case, has been detected in stream water.
In November 1994, responding to concerns about the stability of atrazine in soil and increasing evidence of its movement through soil to groundwater, the U.S. Environmental Protection Agency initiated a special review of atrazine and two other so-called traizine herbicides: cyanazine and simazine.
The manufacturer of atrazine and simazine, Ciba Crop Protection (a subsidiary of Ciba-Geigy AG), continues to deny that there are any adverse health effects associated with the chemicals, so long as they are used properly.
But other, more disinterested parties dispute the company’s claims. In 1994, the Environmental Working Group, a Washington-based nonprofit research organization, called for a phase-out of the triazine herbicides, claiming that their cancer-causing potential is far greater than what the manufacturers acknowledge.
Since then, research into a class of chemicals that interfere with the functioning of the body’s endocrine system (endocrine disruptors) has identified atrazine as a potent mimic of the hormone estrogen. If this is so, cancer might be just one of several possible outcomes of exposure. Others might involve reproductive or developmental problems. In fact, the very reason that the EPA regulated atrazine in the first place was not because of its suspected cancer-causing potential, but because it was linked with cardiac, kidney, and liver damage.
Some of the heaviest contamination occurs along the Hamakua Coast of the Big Island. The municipal system that supplies the town of Pepe`ekeo has been especially hard hit.
From 1986 through 1990, springs that fed the Pepe`ekeo system contained atrazine at well concentrations ranging from about 1 to 1.5 part per billion. (The federal maximum contaminant level is 3 parts per billion, but the safety of this guideline has been disputed.) Since reaching a high in 1990, levels have tapered off, but continue to hover around the 0.5 ppb mark.
Well water used in the Pepe`ekeo water system had for years contained slightly less atrazine than the springs. However, since 1993, well water concentrations of atrazine have been greater than or roughly equal to concentrations in the springs.
The Hawai`i Department of Water Supply has announced plans to develop a new water source for Pepe`ekeo, “located away from contaminated soil,” at an elevation of 1,300 to 1,500 feet. Some $2 million has been placed in the department’s capital improvement budget to cover the cost of drilling.
Stream water quality is not regularly tested in Hawai`i. One of the few areas where has occurred is the Kaiaka-Waialua Bay area along the north shore of O`ahu. There, under a project financed in part by the U.S. Soil Conservation Service (now known as the Natural Resource Conservation Service) and in part by the state Department of Health, researchers assisted by students have collected samples of stream water and have tested them for the presence of atrazine. Along the Kaukonahua River, atrazine levels were as high as 185 parts per trillion. At the Thompson’s Corner branch of the Paukauila River, the concentration was 96 ppt. Atrazine concentrations at the Anahulu River by the old bridge into Hale`iwa were 50 ppt.
The water-quality sampling was not well received by the West O`ahu Soil and Water Conservation District nor Po-Yung Lai, assistant director of the University of Hawai`i Cooperative Extension Service. In a February 16, 1996, memo to the NRCS, Po-Yung Lai stated that the Kaiaka-Waialua Hydrologic Unit Area project “is intended for information and evaluation and is not for monitoring or research. As such, Dan [Janik, the Extension Service’s water quality agent for O`ahu] will be instructed to terminate any monitoring activities and, instead, to concentrate on the educational activities.”
Volume 6, Number 12 June 1996
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