- Ecotoxicology 20
- Environmental Chemistry 16
- Environmental Health 16
- Atmospheric Protection/Air Quality Control/Air Pollution 15
- Waste Water Technology / Water Pollution Control / Water Management / Aquatic Pollution 13
- Environment, general 12
- Monitoring/Environmental Analysis 7
- Soil Science & Conservation 6
- Pollution, general 5
- Ecology 4
- Environmental Management 4
- Climate Change 1
- Climate Change/Climate Change Impacts 1
- Environmental Physics 1
- Geography, general 1
- Nature Conservation 1
- Oceanography 1
- Regional/Spatial Science 1