- Geochemistry 6
- Atmospheric Protection/Air Quality Control/Air Pollution 5
- Ecotoxicology 5
- Environment, general 5
- Environmental Chemistry 5
- Environmental Health 5
- Waste Water Technology / Water Pollution Control / Water Management / Aquatic Pollution 5
- Biogeosciences 2
- Earth Sciences, general 2
- Environmental Science and Engineering 2
- Geology 2
- Hydrology/Water Resources 2
- Nuclear Energy 2
- Nuclear Physics, Heavy Ions, Hadrons 2
- Particle Acceleration and Detection, Beam Physics 2
- Terrestrial Pollution 2
- Agriculture 1
- Chemistry/Food Science, general 1
- Ecology 1
- Engineering, general 1