By Reggie Ellis
The City of Exeter sent a letter to residents last week announcing that one of its four groundwater wells had a high concentration of a banned pesticide.
However, it has never affected drinking water.
The pesticide, Dibromochloropropane (DBCP), was used primarily to kill parasitic worms in soybean cotton, vineyards, tomatoes and tree fruit crops, according to the California Department of Health Services. People who drink water with high DBCP levels for many years may experience reproductive difficulties and may have an increased risk of cancer.
At the May 27 Exeter City Council meeting, Public Works Director Felix Ortiz said the well has been shut off since November, when the average monthly DBCP levels were above the state's Maximum Contaminant Level (MCL). It was the first time that any Exeter wells had tested for high DBCP levels. California Environmental Protection Agency has set the MCL at 0.2 parts per billion, or a microgram per liter. The city's well tested at 0.33 ppb between August and December 2003 for a sixth-month average of 0.27, well over the MCL.
Ortiz said the well did not affect drinking water because the City combines the water from all four wells prior to pumping it through the city's water lines. The "co-mingling" of city water lowers the pesticide level well below anything harmful to humans.
Ortiz said well E06W would only be used during peak months, such as the dry summer, if the city's other three wells could not keep up with demand. E06W is the well with the second largest capacity, pumping 1,200 gallons per minute. He said a new well is being constructed to avoid using E06W but its capacity will only pump 350 gallons per minute. That well will be operating 24 hours a day.
City Engineer Chuck Sanford said the city would have several options to eliminating the problem. They could use a costly method of treating the water, close off the portions of the well that are highest in pesticide levels or plan to build another well to make up for lost capacity.
"If we dig a new well don't we run the risk of creating the same problem [with pesticide levels]?" Mayor Leon Ooley asked.
"Yes, it could," Sanford replied. "This is also a good well for quantity so you may want to keep it."
Ortiz said the city is continuing to test the well even though it is not in use. He said the city must submit a plan to eliminate or lower DBCP levels by Aug. 15. Consumers wanting more information should contact the City of Exeter at 592-3710 or the State Department of Health Services at 447-3300.