Mangroves should not be used as sewage disposal sites. It is killing them mangroves grow in highly saline, coastal waters, representing a very unique ecosystem. According to an estimate, a mangrove forest supports 100 species of plants and about 500 species of animals, birds and fish. These forests also act as filters for nutrients from water; the fine soil sediments act as sinks for a variety of effluents. Thus these forests have long been used as convenient sites for sewage disposal. It was believed to be good for their growth.

A study by Catherine Lovelock of the University of Queensland, Australia, and her colleagues shows that nutrients from the effluents, in fact, contribute to mangrove tree deaths. Excessive nutrients promote excessive growth of the plant