Tests of the raw Lake Erie water near the city of Toledo’s water-intake crib today show a slight decrease in the level of algae toxins in the water since Wednesday.

The tests also show the amount of microcystin in the city’s treated drinking water remains so small that it was undetectable and the city’s water quality dashboard status remains at “watch.” No tests of the city’s treated drinking water this year have registered a detectable amount of the toxin.

The test results from the raw lake water samples today showed 1.1 parts per billion of the toxins, said Stacy Weber, a city spokesman, in a statement. That reading shows lower levels of microcystin than the test results from Wednesday, which revealed 1.3 ppb in the raw lake water.

The water remains safe to drink, city officials said.

City officials detected microcystin in the raw lake water for the first time this year on July 27, when it measured 0.5 ppb. Since then the levels in the raw lake water near Toledo’s intake crib have fluctuated, rising as high as 4.9 ppb on Aug. 12.

Toledo’s treated tap water registered microcystin toxin levels greater than 3 ppb in the early morning hours of Aug. 2, 2014, which prompted officials to issue a do-not-drink order that remained in effect until midmorning Aug. 4.

The highest recorded tap sample was 3.191 ppb on Aug. 2, 2014. The next highest, also that day, was 2.439 ppb.

Though no government standards existed last August, U.S. EPA in May declared it acceptable for people of school-age and older to drink tap water with up to 1.6 parts per billion of microcystin in it. The limit for infants and children younger than 6 years old, pregnant women, nursing mothers, people with liver conditions, and those on dialysis is 0.3 part per billion, the EPA said.

Both numbers are based on 10-day averages and updated a 1998 World Health Organization advisory, which recommended tap water across the world contain no more than 1.0 ppb of the toxin.

First Published September 10, 2015, 9:10 p.m.