| Hainan Dongzhaigang harbour is located in the northeast of Haikou, which belongs to the typical harbour area, It has the most complete, the largest number of species, and the largest mangrove groups, it also has rich tourism resources, biological resources, harbour resources, mineral resources, etc. As a new "business card" of Haikou city, Relevant departments paid a lot of attention on it. But in recent years, as the growth of population, economy, construction industry, the development of tourist attractions, local residents overfishing and fisheries, poultry production activities, reclamation and coastal industry development activities, living sewage and agricultural sewage emissions, the interferenc recent years, as the growth of population, economy, construction industry, the development of tourist attractions, local residents overfishing and fisheries, poultry production activities, reclamation and coastal industry development activities, living sewage and agricultural sewage emissions, the interference of human activities. Such as the increase of tourist number and facilities, and the frequent typhoons, biological invasion, plant diseases, insect pests, and the interference of the natural factors. All above these lead to multiple pressure to the mangrove ecosystem health of Dongzhaigang harbor.(1) The level of soil heavy metal pollution. Cd and Hg is extremely serious in the study area.Cr, Cu and Pb have reached the national secondary standard. From the point of variation coefficient, the northern, central, southern were similar. It is declared that metal pollution range is not big in the study area. Through correlation analysis, found that the correlation coefficient between elements is above 0.5, which shows that pollution of the study area have the same or similar sources(2) The level of soil nutrient pollution. The results of the measurement show that N is almost lower than 30, which is getting in serious lack. Rapidly-available K is more than 200 averagely, which is getting in a state of extremely rich; Most of available P is getting in a state between lack and serious lack. It seems that the soil fertility of the study area is lower than middle levels basically.(3) Water body pollution. Different areas has different,pollution degree. On the whole,wharf is the worst, fishpon is worse than fishpond channels, forest is the smallest among these. Thus it can be seen that water pollution is more serious in where affected a lot by human activity,.(4) The water eutrophication status. Forest ditches is the mild pollution, fish ponds channels belong to the severe pollution; According to the formula 7, all the study areas have been in a state of eutrophication. Terminal area is the worest, protected area which affected by human disturbance seriously.(5) The result of the soil potential ecological pollution index evaluation. The surface soil ecological risk of heavy metals in the study area is mainly originated from the Cd and Hg. Cd has a strong ecological risk between 200-500, Hg is above 300, which reached the highest in 2422.71, it is extremely beyond the scope, both Cr, Cu, and Pb are lower than 40, which belong to light pollution. Cu and As are between 40-80, which belong to the moderate pollution.(6) The results of comprehensive interference intensity evaluation. Comprehensive interference intensity index of the study area was 3.883.And natural interference contribution rate is 46.8%, human interference contribution rate is 53.2%. natural disturbance factors occupied larger proportion. Such as storm, typhoon, biological invasion. Among human factors, fishing and pollution of the environment hold on great proportion. |
