ironically one of the reasons that sailing is so popular on marapendi is, that it is unsafe to swim, canoe or row in the lake due to water pollution. accelerate development in the east zone of rio de janeiro, and a lack of adequate security in the park have allowed illegal landfills to emerge.

according to the state foundation of environmental engineering, water clarity in the region has decreased by 8.5% in recent years. in addition, lack of proper sewage treatment has caused marapendi and the others in its lake network to feel the effects of 'siltation' - the formation of islands from solid matter, that interrupt water flow and hurt the local ecosystem. as a result of this, the trees and wildlife local to the park are under threat.