The conservation group WWF sent a letter to Touch Seang Tana, chairman of Cambodia's Commission to Conserve Mekong River Dolphins and Develop Eco-Tourism, on Tuesday in response to concerns about a recent report on the Mekong River's Irrawaddy dolphin population. The report, released last month, stated that pollution in the Mekong River was in part responsible for the deaths of 88 Irrawaddy dolphins since 2003. It prompted a harsh rebuttal from Touch Seang Tana, who said Tuesday that he had not yet seen the letter.