LOS ANGELES (KABC) -- Popular sections of the Los Angeles River have high levels of fecal bacteria, according to a new report from Heal the Bay which is warning people about swimming and boating activities on the water.The environmental group examined samples from river recreation zones at the Sepulveda Basin and Elysian Valley areas of the river in summer 2015. Those sections have become popular with kayakers as the overall condition of the river has improved in recent years.The samples tested high for certain types of bacteria, including E. coli and enterococcus. Exposure to that water could potentially cause ear infections, respiratory illness and gastrointestinal illness, the group said."Heal the Bay is thrilled about the energy and excitement around restoring the river, but it's critical that water quality improvements don't get left out of the conversation," Heal the Bay watershed scientist Katherine Pease said.The group advised caution when participating in recreational activities on the river. In particular, it advised not swimming in the water, and especially not putting your head under water.When kayaking and angling, people should avoid contact with the water, especially if they have open wounds or compromised immune systems.If there is contact with the water, the skin should be rinsed off with soap and fresh water afterward.Most of the water - about 16 million gallons a day - that flows through the Los Angeles River is treated wastewater from the city of Los Angeles Tillman Recreation Plant in Van Nuys.That plant is not a source of the bacterial contamination, the group said. The bacteria comes from urban runoff, leaks from wastewater collection systems, failing septic systems and waste from animals and humans.