Students conduct 46th annual river testing exercise

Illinois Valley Community College chemistry instructor Larry Ault and natural science lab instructor LeeAnn Johnson guided 26 students in the annual river testing exercise recently.

The group returned to an area on Hogsback Road in north LaSalle. Ault noted it was the 46th test at that site since 1995. The project was initiated a year earlier by Bob Byrne, a chemistry professor at IVCC for 31 years.

Results were above average concerning nitrate and phosphate concentrations but nearly the highest seen in previous years, Ault said, attributing the high phosphate levels to heavy rains and farm planting. Dissolved oxygen levels were good, he added.

An interesting activity took place back at the college, where students observed the hatching of a possible insect larvae or crayfish from a very tiny spherical shell, Ault and Johnson reported.

“Looking through a microscope and displaying the vision on a large screen, one could see eyes, mouthparts, and ferocious-looking claws. The students finally identified it as caddisfly larva,” Ault said. “Think ‘Alien!’ If this caddisfly was six feet tall, it would tear a human being to pieces! The world of the very small macroinvertebrates is a violent world indeed. And they eventually grow up to be many types of flies and insects.”

Ault continued: “Understanding the populations of these little guys help us to understand the health of the river. A lot of water-breathers, like caddisflies, indicate a healthy environment. Lots of air-breathers, such as snails and worms, indicates a polluted system.”

The next river testing event will be in September. IVCC performs two such events each semester with the assistance of biology, chemistry, and geology faculty.