FARMINGTON — Germaine Bradley was careful to swirl the small tube holding a sample of water collected from a brook that runs in Brookside Park.
Bradley, a sophomore from Northwest High School in Shiprock, continued to agitate the sample until the water turned from green to purple as he completed a test to determine its alkalinity.
She was one of 30 students who traveled from Shiprock on Thursday to test the levels of chlorine, bromine, acidity or alkalinity, total hardness and ammonia found in local bodies of water.
Earlier in the day, students collected and tested samples from Morgan Lake near the Four Corners Power Plant.
Sophomore Donya Nargo worked alongside juniors Toni Bruce, Chelsea Nathaniel, Leranda Smith and Alyssa Nakai near the shore.
The procedure for testing total hardness, which refers to the level of dissolved mineral content, required the group to fill the sample tube with water then add indicator drops to check if hardness was present.
After adding the drops, the sample turned red so the students added a second solution and counted the number of drops added until the water changed from red to blue.
It took 35 drops for the sample to change color, which caused a debate among the students.
The next test, for ammonia, revealed that the lake carries an "ideal" level, which was a surprising result.
"I think it's like that because we're by the shoreline," Nathaniel said.
Nargo also questioned the ammonia results then wondered if the level would change if the sample was collected from the lake's center or closer to the power plant.
In an interview during lunch at Brookside Park, Nargo said the results her group had collected made her think twice about where residents on and off the reservation receive water and its quality.
"At home we don't drink water from the fountain," she said. "Sometimes when we drink water from the fountain it tastes funny."
She also noticed a difference in appearance between water collected from the San Juan River in Farmington and in Shiprock.
The field trip provided students the opportunity to combine what they learned in class with their own testing, science teacher Michael-Angel Vazquez said.
Vazquez worked with his students to plan the field trip and to select the testing sites.
"We wanted places that were both on and off the reservation," he said. "We wanted to see if there is a clear distinction in quality between places like Farmington, which is a little bit more affluent than places on the reservation where generally there is more poverty present."
Before the trip, the students learned about water contamination, the Navajo Water Project, the Navajo Water Rights Settlement, and the Winters doctrine, a U.S. Supreme Court decision that clarified water rights for American Indian reservations.
As part of the experiment, the class also tested the water from their school's drinking fountain, restrooms and the bottled water delivered to the administrative office.
"The healthiest was the office water and the fountain water was OK," said junior Miranda Smith.
After returning to the classroom, the students will compare their results with their hypotheses then write their reports.Noel Lyn Smith covers the Navajo Nation for The Daily Times. She can be reached at 505-564-4636 and firstname.lastname@example.org. Follow her on Twitter @nsmithdt on Twitter.