- Environment, general 69
- Atmospheric Protection/Air Quality Control/Air Pollution 53
- Ecotoxicology 51
- Environmental Health 49
- Waste Water Technology / Water Pollution Control / Water Management / Aquatic Pollution 48
- Environmental Chemistry 47
- Soil Science & Conservation 10
- Hydrogeology 7
- Water Quality/Water Pollution 7
- Climate Change/Climate Change Impacts 6
- Ecology 6
- Environmental Management 4
- Agriculture 2
- Animal Physiology 2
- Biological and Medical Physics, Biophysics 2
- Environmental Physics 2
- Meteorology 2
- Plant Physiology 2
- Plant Sciences 2
- Animal Systematics/Taxonomy/Biogeography 1