In order to study the feasibility of using mangrove wetland as a facility for sewage treatment and the effects of wastewater discharge on soil and plants of the mangrove ecosystem,the field work was conducted during December 1994 to December 1995 in a mangrove wetland in Futian national nature reserve in Shenzhen. Two parallel elongated sites (sites A and B, each 180m×10m) stretching from land to sea were chosen for study. Since December 1994, Site A was continuously irrigated with municipal sewage every two days,while Site B served as a control. The ecological impact of sewage discharge on the mangrove wetland was assessed by comparing the plant growth, nutrients of soils and vegetation between Site A and Site B. One year later, total-N and NH 4 +-N in the soil increased and EC decreased significantly at Site A. And obvious changes in pH value and other nutrient contents in the soil of Site A could be detected. However, the nutrient contents of the leaves of the dominant plants collected from Site A and B were very close and no significant difference in terms of tree height and diameter and biomass was found between the two sites.
