- Ecotoxicology 20
- Environmental Chemistry 18
- Atmospheric Protection/Air Quality Control/Air Pollution 17
- Environmental Health 16
- Waste Water Technology / Water Pollution Control / Water Management / Aquatic Pollution 15
- Environment, general 12
- Monitoring/Environmental Analysis 7
- Soil Science & Conservation 7
- Biochemistry, general 6
- Environmental Management 6
- Biotechnology 5
- Ecology 5
- Nutrition 5
- Oncology 5
- Pollution, general 5
- Environmental Science and Engineering 2
- Freshwater & Marine Ecology 2
- Oceanography 2
- Plant Physiology 2
- Agriculture 1