Investigation of Sunlight/Radiation Effects on Crude Oil Slick Adsorption by Avicennia marina's Pneumatophores

摘要

This work was aimed to extract and find the sunlight effects, as the main driver of evaporation which cause loosing the significant oil mass weight during the first hours of spill, on the immediate oil adsorption in the intertidal ecosystems. The research was carried out in the subtropical coastline of the north Persian Gulf which had been subjected to enormous oil spill accidents. Also the selected species are one of the most important intertidal ecosystems' plants that are substantial role in interface of fresh water and saline water. Factorial experiments were designed for some scenarios to find interaction of sunlight effects and other variations such as salinity, EC, pH, DO, Temperature etc. Extraction methods were examined and the optimum of the selected. Retention time or contact time in experiments and extraction time due to Soxhlet method were determined during several test. Multivariate statistical analysis and QA/QC methods were implemented for more accuracy. A drastic reduction of the oil adsorption by the out layer of Avicennia marina's Pneumatophores is achieved in absence of sun light. Additionally the proposed method for crude oil extraction was some time consumer but cheaper than other equipped laboratory methods. The results demonstrated that that the field studies are some destructive but efficient methods for reliable determination of oil content residuals in the Mangroves' tissues after a complete tidal wave which is carrying the oil slick toward the coastlines. The results led us to concentrate on the oil spills in the winter which may cause more short term adsorption and consequently more damages in the coastal valuable habitats. Pneumatophores as one of main and dens tissues of Mangroves can absorb more oil from weathered oil slick which is arrived to the intertidal habitats. The capacity of oil trap in the Pneumatophore area physically may cause more damages in bivalves, benthic and invertebrate fauna. Radiation at winter in the field study area is important but not significantly.