Silvia Izquierdo, Associated Press
Paratriathletes swim in the waters of Copacabana Beach during a training session, in Rio de Janeiro, Brazil, Friday, July 31, 2015. The Brazilian government's data on water pollution in Rio de Janeiro show water near where triathletes are preparing to compete this weekend is "unfit" for swimming.

RIO DE JANEIRO — The Brazilian government's most recent data on water pollution in Rio de Janeiro show that water near where triathletes are preparing to compete this weekend is "unfit" for swimming.

The designation, based on fecal coliform bacteria levels, is available on the website of the Rio de Janeiro environmental agency.

The most recent pollution reading at Copacabana Beach was taken from a sample this past Monday. An Olympic qualifier and Paratriathlon event begins Saturday, and several athletes were already getting into the water Friday morning.

The Rio environmental agency didn't respond to requests for comment about whether they have carried out more recent testing this week.

Teams gathered on Copacabana Beach said the International Triathlon Union (ITU) gave them guarantees the water was safe in the areas where the parathletes trained.

"The information we have is that it's safe to swim," said Amanda Duke, team manager for the U.S. paratriathlon team.

Athletes said that the conditions of the water appeared better than they were expecting. But water experts and the government's own pollution monitoring officials all note that sewage pollution typically isn't something that can be seen by the naked eye.

The ITU said it's not doing its own tests on the water, but has requested specific information from local authorities about the water quality.

On Thursday, The Associated Press released the results of a five-month investigation into Rio's waters. It showed that Olympic venues are rife with disease-causing viruses and bacteria.

The AP study showed that the spot where athletes were entering the water on Copacabana Beach on Friday had a minimal reading of over 2 million human adenovirus per liter — that's 2,000 times the reading that water experts in the U.S. say would be considering highly alarming if seen on beaches in the U.S. or Europe.

Human adenovirus multiply in the intestinal and respiratory tracts of people. These are viruses that are known to cause respiratory and digestive illnesses, including explosive diarrhea and vomiting, but can also lead to more serious heart, brain and other diseases.

The Rio de Janeiro state government and the state environmental agency in press releases blasted the AP report on Thursday as being alarmist and said it was unfair to judge Rio's waters based on viral counts, limits of which are not designated in Brazilian legislation, nor in that of the U.S. or the EU. The agency also questioned the qualifications of the laboratory where the AP samples were analyzed.

David Zee, an oceanography professor at Rio de Janeiro's state university who has long researched pollution in Guanabara Bay, rejected the government's response, saying that in Brazil "it's natural that the authorities react saying that 'everything is fine,' but everything is not fine.

He added that the AP testing "was done in a trustworthy lab."

But the area that was ruled unfit by the Rio environmental agency for swimming earlier this week was based levels of fecal coliforms, which are single-celled organisms that live in the intestines of humans and animals. Fecal coliforms can suggest the presence of cholera, dysentery, hepatitis A and typhoid.

The site ruled unfit for swimming has also been labeled as off limits on at least eight previous occasions this year.

Associated Press writer Jenny Barchfield contributed to this report. Follow Brad Brooks on Twitter: www.twitter.com/bradleybrooks