- Environment, general 24
- Atmospheric Protection/Air Quality Control/Air Pollution 20
- Ecotoxicology 20
- Environmental Health 19
- Waste Water Technology / Water Pollution Control / Water Management / Aquatic Pollution 19
- Environmental Chemistry 17
- Environmental Management 7
- Ecology 5
- Soil Science & Conservation 4
- Sustainable Development 3
- Waste Management/Waste Technology 3
- Water Quality/Water Pollution 3
- Climate Change/Climate Change Impacts 2
- Economic Geology 2
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- Environmental Engineering/Biotechnology 2
- Hydrogeology 2
- Monitoring/Environmental Analysis 2
- Pollution, general 2