Assessment of wetland soil degradation in the Pearl River Estuary based on pollution pressure and degradation characteristics

The comprehensive evaluation of wetland soil quality is of great significance to the optimization management of wetland soil ecosystem and the implementation of restoration measures. Considering the present status of wetlands in the Pearl River Estuary and the model of PSR (pressure-state-response) together , nine pressure indicators were selected from the social and pollution factors, eleven state indicators were selected from biological and biotic aspects and three response indicators were selected from education, management and research; and the degradation evaluation index system of wetland soils of the Pearl River Estuary was constructed. The degradation index (DI) and comprehensive health index (CHI) of each sampling site were calculated by using the data normalization method. Then, the degradation of three typical samples in the study area was analyzed by using YAAHP V3 software. Our results showed that the comprehensive health index (CHI) of most wetlands in the Pearl River Estuary was 6.73-37.52, indicating that the soil generally presented subhealth status. More serious soil degradation were observed, which was driven by the main pollution degradation in Panyu District, compared with Nansha District driven by reclamation, and wetland soil degradation degree of three typical sites followed the order of 11st hongqili wetland (0.4818) > Panyu foreign trade port wetland (0.3426) >Fifth ditch wetland(0.1756). Generally, the soil quality in the Pearl River estuary wetland is not optimistic, estuarine wetland conservation and management work should focus on soil pollution control and reducing the reclamation rate.