Washington Middle School student Maria Garcia said she hears some people speak about how "bad and gross" the stream water is in the Ala Wai Canal.

Garcia said she was happy to participate in a science project that gathered water samples from the mouth of the Ala Wai Canal, although the test results will not be known immediately.

"I liked the way we got to test the water around our district," she said.

About 130 students from Washington Middle School participated in education sessions about stream and ocean pollution yesterday as part of the fifth annual World Water Monitoring Day. Organizers said more than 120,000 people in 81 countries monitored their local waterways last year.

The city, along with the U.S. Army Corps of Engineers, helped organize the event, with technical assistance and donations from engineers with the Hawaii Water Environment Association.

City Storm Water Quality Branch spokeswoman Iwalani Sato said the event provides students an opportunity to learn about how pollution affects streams and the ocean.

"If we’re preparing them right, then we’re going to prepare them to be the next generation of stewards," Sato said.

"Education is the key to preventing pollution."

Sato said a major source of pollution is storm water, including debris from homes and commercial areas.

She said testing has indicated in the past that Makiki Steam and Ala Wai Canal have a high level of pollutants, including phosphates and nitrates found in fertilizers.

But Sato said the pollutants can be reduced with education and preventive measures.

She said illegal dumping into streams can sometimes contribute to flooding, especially during the rainy season.

Sato said she recently received complaints about illegal dumping of trash into Makiki Stream near King Street.

Washington Middle School students plan to do a volunteer cleanup, as part of an Adopt-the-Stream project, she said.

During the field project yesterday, students used water kits to test for the presence of a number of pollutants at Makiki Stream and the Ala Wai Canal, including nitrates.

School teacher Harvey Llantero said the hands-on approach to learning how to conduct water tests provides students with a "launching point" for their future school and science fair projects.

"Their interest is very high," he said.

Eighth-grader Mahealani Wilson said she was happy with the way students worked together to gather test results.

"We got a lot accomplished. … I’m really glad about what we did today," she said.