The New York State Department of Health has issued a do not drink advisory for Rushville and Middlesex.

The department completed testing on Thursday that showed an elevated level of microcystin, a toxin found in blue-green algae. The toxin came from an algae bloom on Canandaigua Lake.

Because water contaminated with microcystin cannot be purified by boiling, people in Rushville and Middlesex are advised to use an alternate source of water for drinking, cooking, making infant formula, making ice, and preparing food and beverages until further notice.

More than 1,900 bottles of water were delivered to the two communities Thursday night, with an additional nine pallets of water arriving later on. The water was available at both of the villages' fire departments.

The water tested from Rushville's supply showed 0.66 micrograms per liter of microcystin. The U.S. Environmental Protection Agency’s 10-day Health Advisory level for bottle fed infants and children under 6 years old is 0.3 micrograms. The elderly and people with a preexisting liver condition are also at higher risk for microcystin poisoning.

Symptoms of microcystin poisoning include stomach pain, nausea, vomiting, diarrhea, severe headaches, and fever. Exposure to large amounts of microcystin is known to cause liver damage.

The DOH says the issue could take up to 48 hours to fix, with a plan in place to purify the water using chlorine. The public will be notified when the water is safe to drink.