Daily News Archive
From October 16, 2001

Pesticides Contaminate Elementary School Wells

A Carroll County elementary school has found elevated levels of arsenic in one of its wells, with the cause traced to the use of arsenic-based pesticides, reported The Baltimore Sun.

The water of one of Winfield Elementary School's two wells tested arsenic levels at 23 parts per billion (ppb) - well below the current federal standard of 50 ppb, but well above the proposed standard of 10 ppb. There was no arsenic detected in the other well.

The contaminated well was capped, but forced to turn back on within hours to keep up with the demand of the school. They are using a "lead and lag" system, which means that the safe well runs until it can no longer provide enough water for the school, and then the arsenic-contaminated well switches on, pumping water into the holding tank, where it is diluted by water from the safe well. Acting facilities director and construction supervisor Raymond Prokop said that the school system is awaiting cost estimates on drilling a new well.

A 1999 National Academy of Sciences study concluded that the current arsenic standard of 50 ppb "could easily" result in a 1-in-100 risk of cancer, and recommended that the acceptable levels be revised downwards "as promptly as possible." The Clinton administration approved 10 ppb standard is the same standard adopted by the European Union and World Health Organization several years ago, but Bush withdrew the approval.

Arsenic is a known carcinogen. According to the American Journal of Epidemiology for March 1, 2001, a study conducted by National Taiwan University researcher in Taipei reported that exposure to arsenic in drinking water at levels of 10.1 ppb to 50 ppb nearly doubled cancer risk compared to the risk in the general population. Cancer risk elevated to about 8 times higher with arsenic levels between 50 ppb and 100 ppb, and were 15 times higher for people exposed to arsenic levels exceeding 100 ppb.

Arsenic is also an endocrine disruptor, interfering with the action of glucocorticoids, which belong to the same family of steroid hormones as estrogen and testosterone, and are responsible for turning on many genes that may suppress cancer and regulate blood sugar. Science News from March 17, 2001 reported that Alan R. Parrish of Texas A&M University in College station and his team of researchers observed hormone-disrupting effects using arsenic concentrations comparable to 10 ppb in water.

Nothing was said about whether the school intends to halt it's pesticide use and switch to safer alternatives.