"They did find that we should be filtering our water in the schools," she said, adding that the band office has agreed to carry out further tests. Roy said the quality of the water source, Mistissini Lake, is very, very good, but down the line in the school the water quality drops noticeably. The students also studied four different types of filtering options, including some traditional methods, such as using moss or a heavy cotton, as well as modern charcoal filters. In their evaluation, the students also took into account cost and environmental impacts of the different filtration methods.