The Niagara County Health Department hasn't given up, but it so far has not been able to find the source of elevated levels of nitrates in this village's water well.
Agricultural fertilizer runoff, regarded as the most likely cause, has been ruled out.
The village closed the reservoir July 11 and has since been purchasing water from the Niagara County Water District exclusively. Previously, the village used the county water as a supplement to its well water.
No permanent decision on the well's future has been made, Village Clerk-Treasurer Rebecca A. Schweigert said Friday.
"We can't make any decisions until we hear from the Health Department," Schweigert said.
The Health Department said high nitrate levels are a danger only to babies in their first six months of life, because older people's digestive systems are developed enough to handle it. But babies could fall victim to methemoglobinemia, or "blue baby syndrome," because of a lack of oxygen in their bloodstreams.
James J. Devald, county environmental health director, said Friday he has a draft report on tests of nine privately owned wells near the village reservoir on Mountain Road in Royalton.
The nine wells, all on Mountain or Mack roads, were tested during August. Devald said none of them exceeded the state regulatory threshold for safe nitrate levels, which is 10 parts per million.
The average was about 6 parts per million, and the results of the samples from the private wells ranged from 0.85 to 9.7.
A routine county drinking water test disclosed a reading of more than 10 in the village water, but it later turned out the results had been read incorrectly and the true figure was 9.9 parts per million. The village closed the well anyway.
Another privately owned well, east of the others, is to be tested this week in an effort to gather more information. Of the nine already tested, only one was being used for drinking water. The others were for farm irrigation or were closed, Devald said.
Devald said the Health Department and Cornell Cooperative Extension examined the farming practices in the area of the well.
"It was their opinion that the elevated nitrate levels should not be considered as caused by agricultural activities," Devald said.
There was some speculation that bird droppings might be to blame, but that has been ruled out, too, Devald said, "Septic systems are a possibility."
Also, Devald said, "There was a mention there were cattle barns in the vicinity."
Middleport's village well has a maximum capacity of 150,000 gallons a day. It supplies 60 percent of the village's water for eight months of the year and 30 percent during the summer months. The county Water District supplies the rest.