Marine pollution Soil pollution 7 Marine ecology 5 Food resources 4 Land resources 4 Oil pollution of the sea 4 Wasteland reclamation 4 Energy resources 3 Forest resources 3 Heavy metals 3 Natural disasters 3 Natural resources 3 Non renewable resources 3 Nuclear pollution 3 Oil pollution 3 Radiation pollution 3 Renewable resources 3 Waste disposal in the ocean 3 Climate change 2 Climatic change 2 Coastal zone management 2 Disaster management 2 Environment 2 Environmental degradation 2 Environmental toxicology 2 Factory and trade waste 2 Global warming 2 Human population 2 Mineral resources 2 Noise pollution 2