A handful of riders on this week’s RAGBRAI trek are filling test tubes along the way. The group is part of IOWATER, volunteers who test the quality of water in Iowa lakes and streams. Lynette Seigley of Iowa City, the RAGBRAI team’s co-captain, says they’ll test 24 different streams along the ride’s route through northern Iowa. They’re looking at the chemistry of the water, the clarity of the water, and the kind of bugs that live in the stream to get an idea of the over-all quality of the water in the streams.Seigley says one site in northwest Iowa had relatively high nitrate levels, but over-all, the test results have been pretty good. They’re taking into account that the dry weather in some regions affects the quality of the water. They’ll test sites in Rock Falls and Charles City tonight. On Sunday, streams in or near Sioux Center, Granville and Marcus were tested. On Monday, tests were conducted near Cherokee, Rembrandt, Ayrshire and Emmetsburg. On Tuesday, tests were conducted near Fenton and Titonka. Today, tests will be done near Rock Falls and Charles City. On Thursday, tests will be done near Tripoli and Sumner. On Friday, tests will be done near Quasqueton and Central City and on Saturday, a test will be conducted near Anamosa.