No alrets issued so far this season

Past late-season algae blooms in Grand Lake and Shadow Mountain Reservoir have prompted a series of algae tests being conducted in Colorado-Big Thompson Project reservoirs and Grand Lake.

Bi-weekly and weekly sample-taking and testing, amounting to $40,000, is taking place in Grand Lake, Shadow Mountain, Granby, Willow Creek and Windy Gap reservoirs as part of a program funded by six agencies.

Algae blooms develop in water bodies from increased water temperature and nutrient enrichment.

A certain blue-green algae can develop algal toxins, which given sufficient concentration can produce negative health effects from drinking water and some lake recreation.

Some summer residences on Grand Lake utilize lake water for domestic use.

The tests are being performed into October, and if a health concern develops from test results, a Grand County Emergency Algal Toxin Response Plan is already in place, approved by Grand County commissioners last Tuesday.

The plan outlines levels of toxins that exceed safe drinking water values established by the World Health Organization and when it is appropriate to issue drinking water and swimming advisories.

Algae toxin in concentration above 1 migrogram per liter in drinking water can have negative health effects, the Organization states, and concentrations from 2 to 20 migrograms per liter have low to moderate probability of adverse health effects including short and long-term illnesses. Concentrations greater than 20 micrograms per liter pose a risk of acute poisoning. A 132-pound adult is used to establish these values, but with a child, levels affecting health are lower.

Grand County, the Three Lakes Association, the Greater Grand Lake Shoreline Association, the Town of Grand Lake, Northern Colorado Water Conservancy District and the Colorado River Water Conservation District are sharing the costs of the sampling and analyses.

— Tonya Bina can be reached at 887-3334 ext. 19603 or e-mail tbina@grandcountynews.com.